SEABANK 3
Preliminary Environmental Information Report Volume I
Prepared for:SSE plcMay 2014
Seabank 3 PEI Report - Preface
May 2014
PREFACE
This document comprises the Volume I of the Preliminary Environmental Information Report
that has been prepared in support of a DCO Application for the construction and operation of
Seabank 3.
The Preliminary Environmental Information Report comprises the following documents:
• The Non Technical Summary;
• Volume I: Preliminary Environmental Information Report;
• Volume II: Technical Appendices; and
• Volume III: Figures.
Figures based on Ordnance Survey® maps in this report have been reproduced under OS
License. © Crown copyright, All rights reserved. 2013. Licence number 0100031673.
Seabank 3 PEI Report - Preface
May 2014
Project Title: Seabank 3
Report Title: Preliminary Environmental Information Report: Volume I
Project No: 47064101
Client Name: SSE
Issued By: URS Infrastructure & Environment UK Limited
Document Production / Approval Record
Issue No: Name Signature Date Position
Prepared by
Natalie Williams Natalie Williams May 2014 Environmental Consultant
Checked by
Neil Titley Neil Titley May 2014 Associate
Approved by
Richard Lowe Richard Lowe May 2014 Technical Director
Document Revision Record
Issue No Date Details of Revisions
1 May 2014 PEI Report
Seabank 3 PEI Report – Glossary
May 2014
Abbreviations
Abbreviation Term
” Inch
°C Celsius
µg/m3 Micrograms per Cubic Metre
AADT Annual Average Daily Traffic
ABI Annual Business Inquiry
AGI Above Ground Installation
AOD Above Ordinance Datum
APFP Applications: Prescribed Forms and Procedure
APHO Association of Public Health Observatories
AQAP Air Quality Action Plan
AQMA Air Quality Management Area
ATC Automatic Traffic Count
AWTS Avon Wildlife Trust Site
BAP Biodiversity Action Plan
BAT Best Available Techniques
BCC Bristol City Council
BCHER Bristol City HER
BDW Boiler Feed Water
bgl Below Ground Level
BGS British Geological Survey
BIS Business Innovation and Skills
BOCC Bird of Conservation Concern
BRE Building Research Establishment
BREF Reference Document
BRERC Bristol Regional Environmental Records Centre
BRO Bristol Records Office
BS British Standard
BTEX Benzene, Toluene, Ethylbenzene and Xylenes
BTO British Trust for Ornithology
CAA Civil Aviation Association
CBR California Bearing Ratio
CCGT Combined Cycle Gas Turbine
CCR Carbon Capture Ready
CCS Carbon Capture and Storage
CCTV Closed Circuit Television
CCW Countryside Council for Wales
CDM Construction Design and Management
Seabank 3 PEI Report – Glossary
May 2014
Abbreviation Term
CEMARS Certified Emissions Management and Reduction Scheme
CEMP Construction Environmental Management Plan
CEMS Continuous Emissions Monitoring System
CFA Continuous Flight Auger
CHP Combined Heat and Power
CIEEM Chartered Institute of Ecology and Environmental Management
CLPVEs Critical Levels Protection of Vegetation and Ecosystems
CLR11 Defra’s Contaminated Land Report 11
CMS Construction Method Statement
CO Carbon Monoxide
CO2 Carbon Dioxide
COMAH Control of Major Accident Hazards
COPA Control of Pollution Act 1974
COSHH Control of Substances Hazardous to Health
CPT Cone Penetration Test
CRoW The Countryside and Rights of Way Act 2000
CRTN Calculation of Road Traffic Noise
CSM Conceptual Site Model
CTMP Construction Traffic Management Plan
CW Chemical Warfare
DAS Design and Access Statement
dB Decibel
DCLG Department for Communities and Local Government
DCMS Demolition and Construction Method Statement
DCO Development Consent Order
DECC Department for Energy and Climate Change
DETR Department for the Environment, Transport and the Regions
DfT Department for Transport
DMRB The Design Manual for Roads and Bridges
DOE Department of the Environment
DPDs Development Plan Documents
DQRA Detailed Quantitative Risk Assessment
EA Environment Agency
EfW Energy from Waste
EH English Heritage
EIA Environmental Impact Assessment
ELVs Emission Limit Values
EMF Electromagnetic Fields
EMR Electricity Market Reform
Seabank 3 PEI Report – Glossary
May 2014
Abbreviation Term
EOH Equivalent Operating Hours
EPC Engineering, Procurement and Construction Contractor
EPUK Environmental Protection UK
EQS Environmental Quality Standards
ES Environmental Statement
FRA Flood Risk Assessment
FTE Full Time Equivalent
FTW Full Time Equivalents
GAC Generic Assessment Criteria
GCC Gloucestershire County Council
GI Ground Investigation
GIS Gas Insulated Switchgear
GPSS Government Pipeline and Storage System
GQRA Generic Quantitative Risk Assessment
GW Gigawatt
GWh/day Gigawatt hour per day
H2 Hydrogen
ha Hectare
HA Highways Agency
HAZOP Hazard and Operability Assessment
HC Hydrocarbons
HDD Horizontal Directional Drilling
HDV Heavy Duty Vehicle
HER Historic Environment Record
HGV Heavy Goods Vehicle
HIA Health Impact Assessment
HPA Health Protection Agency
HRA Habitats Regulations Assessment
HRSG Heat Recovery Steam Generator
Hz Hertz
IAQM Institute of Air Quality Management
IBA Important Bird Area
ICE Institution of Civil Engineers
ICNIRP International Commission on Non-Ionising Radiation Protection
IEA Institute of Environmental Assessment
IED Industrial Emissions Directive
IEEM Institute of Ecology and Environmental Management
IEMA The Institute of Environmental Management and Assessment
IMD Index of Multiple Deprivation
Seabank 3 PEI Report – Glossary
May 2014
Abbreviation Term
IPC Infrastructure Planning Commission
IPPC Integrated Pollution Prevention and Control Directive
IROPI Imperative Reasons of Overriding Public Interest
ISO International (ISO) Standards
IUCN International Union for Conservation of Nature
JSNA Joint Strategic Needs Assessment
kg Kilogram
km Kilometre
kV kilovolt
kWh Kilowatt hour
LCPD Large Combustion Plant Directive
LNG Liquefied Natural Gas
LNR Local Nature Reserves
LSIDB Lower Severn Internal Drainage Board
Lw Sound Power Levels
m Metre
m/s Metres per second
MAGIC Multi-agency Geographic Information for the Countryside
mbars Milibars
mm Millimetre
mm/s Millimetre per second
MMO Marine Management Organisation
MMP Materials Management Plan
MW Megawatt
MWe Megawatt Electrical
NAQS National Air Quality Strategy
NE Natural England
NERC Natural Environment and Rural Communities
NETS National Electricity Transmission System
NG National Grid
ng/m3 Nanograms per cubic metre
NGG National Grid Gas
NH3 Ammonia
NID National Infrastructure Directorate
NNR National Nature Reserve
NO2 Nitrogen Dioxide
NOx Nitrogen
NPPF National Planning Policy Framework
NPS National Policy Statement
Seabank 3 PEI Report – Glossary
May 2014
Abbreviation Term
NR National Rail
NSIP National Significant Infrastructure Project
NTS Non-Technical Summary
NTS National Transmission System
O4B Open4Business
OCGT Open Cycle Gas Turbine
ODPM Office of the Deputy Prime Minister
OHLs Overhead Line
ONS Office for National Statistics
OS Ordinance Survey
PAH Polycyclic Aromatic Hydrocarbons
Pb Lead
PEI Preliminary Environmental Information
PHE Public Health England
PIAs Personal Injury Accidents
PIG Pipeline Inspection Gauge
PINS The Planning Inspectorate
PM10 Particulate Matter
PM2.5 Particulate Matter
PPG Pollution Prevention Guidelines
ppm Parts Per Million
ppv Peak Particle Velocity
PRA Preliminary Risk Assessment
PROW Public Right of Way
PVC Polyvinyl Chloride
RBMP River Basin Management Plans
ROW Right of Way
SAC Special Area Conservation
SDL` Severnside Developments Ltd
SERC Severnside Energy Recovery Centre
SGC South Gloucestershire Council
SGHER South Gloucestershire HER
SINC Site of Importance for Nature Conservation
SITA The Severnside Energy Recovery Centre
SNCI Sites of Nature Conservation Interest
SO2 Sulphur Dioxide
SoCC Statement of Community Consultation
SoS Secretary of State
SPA Special Protection Area
Seabank 3 PEI Report – Glossary
May 2014
Abbreviation Term
SPDs Supplementary Planning Documents
SPGs Supplementary Planning Guidance
SPL Seabank Power Ltd
sq ft Square foot
SSAC Site Specific Assessment Criteria
SSSI Site of Special Scientific Interest
SuDS Sustainable Urban Drainage System techniques
TA Transport Assessment
TPO Tree Preservation Order
TTWA Travel to Work Area
UK BAP UK Biodiversity Action Plan
ULCS Ultra Large Container Ship
UWE University of West of England
UXO Unexploded Ordnance
VOCs Volatile Organic Compounds
WAC Waste Acceptance Criteria
WAP1 Western Approaches Business Park
WeBS Wetland Bird Survey
WebTAG Web-based Transport Analysis Guidance
WFD Water Framework Directive
WHO World Health Organisation
WNS Wildlife Network Site
WSI Written Schemes of Investigation
WTNs Waste Transfer Notes
WWII World War Two
WWTW Waste Water Treatment Works
ZTV Zone of Theoretical Visibility
Seabank 3 PEI Report – Glossary
May 2014
Glossary of Terms
PEI Report Preliminary Environmental Information Report
Ancillary Development
A range of matters including acquisition of land, intrusive works and other connections and agreements (defined by The Planning Act 2008, Section 120).
Associated Development
Development associated with the principal development within the site for which DCO is being sought, such as pipework, control rooms, water supply, storage and purification equipment, gas receiving equipment, grid connection infrastructure and supporting site infrastructure (defined by The Planning Act 2008, Section 120).
Associated Infrastructure
A reference in the PEI Report to Associated Development located outside of the Proposed Development Site (but still within the DCO Site). It includes cooling water pipeline, and electrical and utilities connections.
Black-start The ability to start-up without assistance from the national electricity grid in the event of a total or partial shutdown of the national transmission system.
Carbon Capture Ready (CCR)
A generating station that adheres to the UK CCR Guidance. A generating station that is CCR will have sufficient land adjacent to the generating station to install carbon capture technology at some point in the future, should the technology become viable.
Carbon Capture Storage
Carbon capture and storage (CCS) is the process of capturing waste carbon dioxide (CO2) from a power plant and transporting it to a storage site (an underground reservoir for example).
Combined Cycle Gas Turbines (CCGT)
CCGT is a form of highly efficient energy generation technology that combines a gas-fired turbine with a steam turbine. It captures waste heat from the gas-fired turbine which would otherwise be emitted to atmosphere to drive the steam turbine, hence increasing the electrical efficiency of the plant.
CCR Site This is an area of approximately 6.3ha within the eastern part of the Proposed Development Site which is reserved for the future retrofit of Carbon Capture plant should this ever be required.
CHP Ready A generating station that adheres to the UK CHP Guidance. A generating station that is CHP-R is designed to be ready, with minimum modification, to export heat should the demand become available.
Cooling Water Pipeline
A proposed water supply pipeline that connects the Proposed Development to the Bristol Waste Water Treatment Works.
Cooling Water Pipeline Corridor
A corridor or area within which the proposed cooling water pipeline and enabling and construction works associated with the pipeline will be installed and completed.
DCO Site The application site for which DCO is being sought. It comprises an area of approximately 38ha and constitutes the following two components: The ‘Proposed Development Site’ and ‘Other DCO Land’.
Development Consent Order
A development consent order, when issued, combines the grant of planning permission with a range of other consents that in other circumstances have to be applied for separately, such as listed building consent. All applications for development consent orders will be made to the Planning Inspectorate. The Planning Inspectorate makes a recommendation to the Secretary of State, who in turns determines the application.
Development Parcels Areas of land within the DCO Site that have been designated for different uses within the PEI Report.
Seabank 3 PEI Report – Glossary
May 2014
PEI Report Preliminary Environmental Information Report
Dry-cooling A type of cooling system that uses air to cool the steam exiting a gas turbine.
Electrical Connection The underground or above ground connection of the Proposed Development to Seabank substation that extends approximately 440m across the existing Seabank 1 & 2 site.
Environmental Impact Assessment
A process for determining how a Project may affect the environment. The results of an Environmental Impact Assessment should establish a development’s principal potential effects, their significance and how they interact. This information is summarised in a Preliminary Environmental Information Report or Environmental Statement, depending on what stage the project is at.
Environmental Statement
A report describing the findings and conclusions of the Environmental Impact Assessment process.
Finished Floor Level The finished level of the upper surface of the floor inclusive of all services.
Generating Station Site
The area within the Proposed Development Site where the generation equipment is located.
Heat Recovery Steam Generator
A heat recovery steam generator or HRSG is an energy recovery heat exchanger that recovers heat from a hot gas stream.
Hybrid Cooling System
A cooling system that extracts waste heat to the atmosphere and uses a mixture of air and water to cool the steam exiting the gas turbine.
Multi-shaft A configuration of CCGT that includes two gas turbines and generators (the same number as two single-shaft units), but supplies steam from the HRSG to a separate steam turbine and generator that is common to each train.
Nationally Significant Infrastructure Project
Infrastructure projects which are dealt with by the Planning Inspectorate are known as Nationally Significant Infrastructure Projects (NSIPs). Projects are within the five general fields of energy, transport, water, waste water and waste. Examples include power stations, railways and major roads, reservoirs, harbours, airports, wind farms and sewage treatment works. The thresholds are set out in sections 15-30 of the 2008 Planning Act.
The Proposed Development falls within the definition of a ‘Nationally Significant Infrastructure Project’ (NSIP) under Section 14(1)(a) and Sections 15(2) of the Planning Act 2008 (Ref. 2-1), as it is an onshore generating station within England that will have a generating capacity greater than 50MW gross output.
Open cycle A form of energy generation technology that does not capture waste heat to fire a steam turbine.
Other DCO Land Approximately 19ha of land within the DCO Site that is outside of the Proposed Development Site and contains the proposed electrical and utilities connection and proposed cooling water pipeline corridor.
Peaking Plant Generating plant that is designed to operate for short periods of time and to ‘top up’ the national grid during periods of high demand / peaks.
Planning Inspectorate
The agency responsible for operating the planning process for nationally significant infrastructure projects (NSIPs).
Preliminary Environmental Information (PEI)
PEI is defined in the Infrastructure Planning (Environmental Impact Assessment) Regulations 2009 as “information referred to in Part 1 of Schedule 4 (information for inclusion in environmental statements) which (a) has been compiled by the applicant; and (b) is reasonably required to assess the environmental effects of the development (and of any associated development)”.
Seabank 3 PEI Report – Glossary
May 2014
PEI Report Preliminary Environmental Information Report
Prescribed Persons Includes certain statutory consultees such as the Environment Agency and Natural England, relevant statutory undertakers, relevant local authorities, those with an interest in the land, and those who may be affected by the development.
Proposed Development Site
Part of the DCO Site comprising approximately 19ha situated immediately east of the existing Seabank 1 & 2 station for which DCO is being sought for the Proposed Development. It excludes the Other DCO Land, which contain the proposed cooling water corridor and electrical connection and utilities.
Public Right of Way An access track that is open to everyone including roads, paths or tracks, bridleways and can run through towns, countryside or private property.
Reciprocating Engine A highly efficient internal heat combustion engine which can achieve long-term availability levels and would be used for the Peaking Plant element of the Proposed Development.
Rochdale Envelope An approach that allows a range, or envelope of parameters to be applied for, as described in the Planning Inspectorate’s Advice Note 9.
Scoping A stage which occurs early in the project cycle identifying the key environmental issues and the procedures for determining the extent of and the approach to an EIA.
Scoping Opinion The Planning Inspectorate will consult the relevant consultees on the submitted scoping report, and will provide consolidated written opinion on the procedures for determining the extent of and the approach to an EIA.
Scoping Report A report by the Applicant on the results of the Scoping exercise as detailed above which is submitted to the Planning Inspectorate.
Single-shaft A configuration of CCGT that consists of only one gas turbine, steam turbine, generator and HRSG per CCGT unit, with the gas turbine and steam turbine coupled to the generator.
Supplementary Firing A method of producing additional steam to generate additional electricity for short periods by firing a dedicated gas burner located between the gas turbine and the HRSG.
The Applicant SSE Seabank Land Investments Limited, a wholly owned subsidiary of SSE.
The Proposed Development
The term used to describe the Seabank 3 generating station. It excludes the cooling water pipeline corridor and electrical connection and utilities.
The Proposed Development Site
Approximately 19ha of the DCO Site that consists of the Seabank 3 generating station and CCR Site. It is wholly located within the administrative boundary of South Gloucestershire Council.
Utilities, Services and Landscaping Area
A 6.4ha area reserved for utilities connections, gas reception and landscaping, excluding the electrical connection and cooling water pipeline.
Wet-cooling A cooling system that uses water to cool the steam exiting a gas turbine.
Seabank 3 PEI Report – Volume I: Contents
May 2014
Contents
1. INTRODUCTION .......................................................................................... 1-1
1.1. Background ................................................................................................... 1-1 1.2. The Applicant ................................................................................................ 1-1 1.3. Location of the Proposed Development ......................................................... 1-1 1.4. The Proposed Development………………………….......................... ............. 1-2 1.5. Structure of this PEI Report…………………………………………… ............... 1-3 1.6. The Purpose of the Preliminary Environmental Information (PEI) Report ....... 1-3 1.7. Location of Information within the PEI Report ............................................... 1-4 1.8. Other Required Consents .............................................................................. 1-5 1.9. References ................................................................................................... 1-6
2. THE DEVELOPMENT CONSENT ORDER (DCO) AND EIA PROCESSES ............................................................................................... 2-1
2.1. Introduction .................................................................................................... 2-1 2.2. DCO Process ............................................................................................... 2-1 2.3. EIA Development .......................................................................................... 2-2 2.4. The EIA Scoping Exercise ............................................................................ 2-3 2.5. Non Key Issues ............................................................................................ 2-4 2.6. Preliminary Environmental Information ......................................................... 2-6 2.7. Design Parameters Used within the DCO Application ................................... 2-7 2.8. Consultation ................................................................................................. 2-8 2.9. PEI Report Availability ................................................................................. 2-10 2.9. References .................................................................................................. 2-11
3. THE SITE AND ITS SURROUNDINGS ........................................................ 3-1
3.1. Introduction ................................................................................................... 3-1 3.2. The Proposed Development Site ................................................................... 3-2 3.3. Existing Services with the Proposed Development Site ................................ 3-8 3.4. Proposed Development Site History ............................................................. 3-9 3.5. Area Surrounding the Proposed Development Site .......................................3-11 3.6. Other DCO Land.......................................................................................... 3-12 3.7. Sensitive Receptors in the Vicinity of the Proposed Development Site
and Other DCO Land .................................................................................. 3-18
4. PROJECT DESCRIPTION ........................................................................... 4-1
4.1. Introduction ................................................................................................... 4-1 4.2. Overview ...................................................................................................... 4-1 4.3. Description of the Proposed Development .................................................... 4-2 4.4. Hours of Operation and Shift Pattern ........................................................... 4-28 4.5. Employment ................................................................................................ 4-28 4.6. Nuisance Control ......................................................................................... 4-29 4.7. Operational Waste Streams ......................................................................... 4-29 4.8. Chemical and Utility Usage .......................................................................... 4-30 4.9. Safety and Emergency Planning .................................................................. 4-31 4.10. References .................................................................................................. 4-32
Seabank 3 PEI Report – Volume I: Contents
May 2014
5. ENABLING WORKS AND CONSTRUCTION .............................................. 5-1
5.1. Introduction ................................................................................................... 5-1 5.2. Enabling Works ............................................................................................ 5-1 5.3. Construction Phase ...................................................................................... 5-5 5.4. Operation .....................................................................................................5-19 5.5. Decommissioning ........................................................................................ 5-19 5.5. References .................................................................................................. 5-22
6. PROJECT NEEDS AND ALTERNATIVES ................................................... 6-1
6.1. The Need for the Proposed Development ..................................................... 6-1 6.2. Alternative Sites ............................................................................................ 6-2 6.3. Consideration of Alternative Locations with the Selected Site ....................... 6-3 6.4. Consideration of Alternative Layouts within the Selected Site ....................... 6-4 6.5. Alternative Technologies .............................................................................. 6-7 6.6. Associated Infrastructure .............................................................................6-11 6.7. Conclusions .................................................................................................6-11 6.8. References .................................................................................................. 6-11
7. ASSESSMENT METHODOLOGY ............................................................... 7-1
7.1. Introduction ................................................................................................... 7-1 7.2. EIA Methodology .......................................................................................... 7-1 7.3. Structure of this PEI Report .......................................................................... 7-5 7.4. Structure of PEI Report Chapters ................................................................. 7-7 7.5. Assumptions and Limitations .......................................................................7-14 7.6. References ..................................................................................................7-14
8. PLANNING POLICY CONTEXT ................................................................... 8-1
8.1. Introduction ................................................................................................... 8-1 8.2. The Planning Act and National Policy Statements for Energy ....................... 8-1 8.3. Other Relevant National Policy ..................................................................... 8-3 8.4. Local Planning Policy ................................................................................... 8-4 8.5. References ................................................................................................... 8-6
9. LAND USE, RECREATION AND SOCIO-ECONOMICS .............................. 9-1
9.1. Introduction ................................................................................................... 9-1 9.2. Assessment Methodology and Significance Criteria ..................................... 9-3 9.3. Baseline Conditions ...................................................................................... 9-6 9.4. Development Design and Impact Avoidance ............................................... 9-11 9.5. Potential Effects and Mitigation Measures ...................................................9-11 9.6. Residual Effects .......................................................................................... 9-22 9.7. Cumulative Effects .......................................................................................9-23 9.8. Impacts and Effects yet to be Determined ...................................................9-24 9.9. References ..................................................................................................9-25
Seabank 3 PEI Report – Volume I: Contents
May 2014
10. TRAFFIC AND TRANSPORT .....................................................................10-1
10.1. Introduction ..................................................................................................10-1 10.2. Assessment Methodology and Significance Criteria ....................................10-3 10.3. Baseline Conditions .....................................................................................10-9 10.4. Development Design and Impact Avoidance ............................................. 10-14 10.5. Potential Effects and Mitigation Measures ................................................. 10-15 10.6. Residual Effects ......................................................................................... 10-30 10.7. Cumulative Effects ..................................................................................... 10-30 10.8. Impacts and Effects yet to be Determined ................................................. 10-33 10.9. References ................................................................................................. 10-34
11. AIR QUALITY ..............................................................................................11-1
11.1. Introduction ..................................................................................................11-1 11.2. Assessment Methodology and Significance Criteria .....................................11-5 11.3. Baseline Conditions .................................................................................... 11-23 11.4. Development Design and Impact Avoidance .............................................. 11-34 11.5. Potential Effects and Mitigation Measures ................................................. 11-36 11.6. Residual Effects.......................................................................................... 11-50 11.7. Cumulative Effects ...................................................................................... 11-52 11.8. Impacts and Effects yet to be Determined .................................................. 11-54 11.9. References ................................................................................................. 11-55
12. NOISE AND VIBRATION ............................................................................12-1
12.1. Introduction ...................................................................................................12-1 12.2. Assessment Methodology and Significance Criteria ....................................12-3 12.3. Baseline Conditions ................................................................................... 12-12 12.4. Development Design and Impact Avoidance .............................................. 12-14 12.5. Potential Effects and Mitigation Measures ................................................. 12-15 12.6. Residual Effects.......................................................................................... 12-31 12.7. Cumulative Effects ...................................................................................... 12-32 12.8. Impacts and Effects yet to be Determined ................................................. 12-33 12.9. References ................................................................................................ 12-33
13. GROUND CONDITIONS .............................................................................13-1
13.1. Introduction ...................................................................................................13-1 13.2. Assessment Methodology and Significance Criteria .................................... 13-3 13.3. Baseline Conditions .....................................................................................13-7 13.4. Development Design and Impact Avoidance ............................................. 13-26 13.5. Potential Effects and Mitigation Measures ................................................. 13-26 13.6. Residual Effects.......................................................................................... 13-39 13.7. Cumulative Effects ...................................................................................... 13-41 13.8. Impacts and Effects yet to be Determined .................................................. 13-43 13.9. References ................................................................................................ 13-44
Seabank 3 PEI Report – Volume I: Contents
May 2014
14. FLOOD RISK, HYDROLOGY AND WATER RESOURCES .........................14-1
14.1. Introduction ...................................................................................................14-1 14.2. Assessment Methodology and Significance Criteria ....................................14-4 14.3. Baseline Conditions .....................................................................................14-8 14.4. Development Design and Impact Avoidance ............................................. 14-15 14.5. Potential Effects and Mitigation Measures ................................................. 14-16 14.6. Residual Effects.......................................................................................... 14-28 14.7. Cumulative Effect ...................................................................................... 14-33 14.8. Impacts and Effects yet to be Determined ................................................. 14-35 14.9. References ................................................................................................ 14-36
15. ARCHAEOLOGY AND CULTURAL HERITAGE ........................................15-1
15.1. Introduction .................................................................................................. 15-1 15.2. Assessment Methodology and Significance Criteria ....................................15-3 15.3. Baseline Conditions .....................................................................................15-8 15.4. Development Design and Impact Avoidance ............................................. 15-27 15.5. Potential Effects and Mitigation Measures .................................................. 15-28 15.6. Residual Effects ......................................................................................... 15-33 15.7. Cumulative Effects ..................................................................................... 15-36 15.8. Impacts and Effects yet to be Determined .................................................. 15-37 15.9. References ................................................................................................. 15-37
16. ECOLOGY AND HABITATS ........................................................................16-1
16.1. Introduction ..................................................................................................16-1 16.2. Assessment Methodology and Significance Criteria ....................................16-5 16.3. Baseline Conditions .................................................................................... 16-15 16.4. Development Design and Impact Avoidance .............................................. 16-31 16.5. Potential Effects and Mitigation Measures .................................................. 16-33 16.6. Residual Effects.......................................................................................... 16-46 16.7. Cumulative Effects ...................................................................................... 16-48 16.8. Impacts and Effects yet to be Determined .................................................. 16-50 16.9. References ................................................................................................. 16-52
17. LANDSCAPE AND VISUAL.........................................................................17-1
17.1. Introduction ..................................................................................................17-1 17.2. Assessment Methodology and Significance Criteria ................................... 17-12 17.3. Baseline Conditions .................................................................................... 17-19 17.4. Development Design and Impact Avoidance .............................................. 17-29 17.5. Potential Effects and Mitigation Measures .................................................. 17-30 17.6. Residual Effects.......................................................................................... 17-40 17.7. Cumulative Effects ...................................................................................... 17-42 17.8. Conclusions ................................................................................................ 17-44 17.9. References ................................................................................................. 17-46
Seabank 3 PEI Report – Volume I: Contents
May 2014
18. SUSTAINABILITY AND CLIMATE CHANGE .............................................18-1
18.1. Introduction ..................................................................................................18-1 18.2. Assessment Methodology and Significance Criteria ....................................18-1 18.3. Baseline Conditions .....................................................................................18-2 18.4. Development Design and Impact Avoidance ................................................18-2 18.5. Potential Effects and Mitigation Measures ...................................................18-2 18.6. Residual Effects.......................................................................................... 18-11 18.7. Cumulative Effects ...................................................................................... 18-11 18.8. Impacts and Effects yet to be Determined .................................................. 18-11 18.9. References ................................................................................................. 18-12
19. HEALTH ......................................................................................................19-1
19.1. Introduction ..................................................................................................19-1 19.2. Assessment Methodology and Significance Criteria ....................................19-2 19.3. Baseline Conditions .....................................................................................19-4 19.4. Development Design and Impact Avoidance ...............................................19-8 19.5. Potential Effects and Mitigation Measures ....................................................19-9 19.6. Residual Effects.......................................................................................... 19-17 19.7. Cumulative Effects ...................................................................................... 19-18 19.8. Impacts and Effects yet to be Determined .................................................. 19-19 19.9. References ................................................................................................. 19-19
20. CUMULATIVE EFFECTS ............................................................................20-1
20.1. Introduction .................................................................................................. 20-1 20.2. Legislation and Planning Policy Context ......................................................20-1 20.3. Assessment Methodology ............................................................................20-2 20.4. Combined Effects of Individual Effects - Type 1 ...........................................20-3 20.5. Combined Effects of the Proposed Development with Other
Development Schemes - Type 2 ..................................................................20-4 20.6. References ..................................................................................................20-5
21. RESIDUAL EFFECTS .................................................................................21-1
21.1. Introduction .................................................................................................. 21-1 21.2. Background .................................................................................................21-1 21.3. Summary of Residual Effects .......................................................................21-1 21.4. Summary and Conclusions ..........................................................................21-5
Seabank 3 PEI Report – Volume I: Contents
May 2014
Tables
Table 1-1 Location of Information within the PEI Report
Table 3-1 Historical Map Descriptions of the Proposed Development Site
Table 4-1 Proposed Development Parameters for the Single Shaft Configuration
Table 4-2 Proposed Development Parameters for the Multi Shaft Configuration
Table 4-3 Provision of Employment during Operation
Table 4-4 Expected Waste Streams associated with the Operational Proposed
Development
Table 4-5 Utility Usage
Table 5-1 Indicative Enabling and Construction Programme
Table 5-2 Estimated Plant Type and Equipment during Construction Activities
Table 7-1 Location of Schemes Considered within the Cumulative Effect Assessment
Table 9-1 Relevant Scoping Opinion Responses
Table 9-2 Socio-economic Effects by Geographical Scale
Table 9-3 Qualification Levels of the Working Population (aged 16-64)
Table 9-4 Employment by Occupation, July 2012 to June 2013
Table 9-5 Sector Employment Distribution, 2012
Table 9-6 Net Construction Employment in Bristol TTWA during the Peak Construction
Year
Table 9-7 Net Operation Employment
Table 9-8 Summary of Residual Effects
Table 9-9 Summary of Schemes Relevant to Cumulative Socio-Economic Effects
Table 10-1 Summary of Stakeholders Comments on Traffic and Transport
Table 10-2 Personal Injury Accident Data (01 May 2008 to 30 April 2013)
Table 10-3 Traffic Increase during Land Raising Works Prior to Additional Mitigation
Table 10-4 Traffic Increase during Land Raising Prior to Additional Mitigation – Sensitivity
Test
Table 10-5 Traffic Increase during Main Construction Works Prior to Additional
Mitigation
Table 10-6 Predicted Increase during Construction Phase following Mitigation Measures
Table 10-7 Summary of Residual Effects
Table 10-8 Predicted Cumulative Effects (Total Traffic including HGVs)
Table 11-1 Summary of Consultation Responses Relevant to Air Quality
Table 11-2 Air Quality Strategy Objectives – Protection of Human Health
Table 11-3 Critical Levels for the Protection of Vegetation and Ecosystems
Table 11-4 Alternative Design Schemes for Combustion Plant
Table 11-5 Modelled Stack Release Parameters
Table 11-6 Operational Phase – Potential Human Health Receptors
Table 11-7 Statutory Designated Sites of Ecological Interest within 10km of the Proposed
Development Site
Table 11-8 Descriptors Applied to the Predicted Adverse Effects of Fugitive Emissions of
Particulate Matter
Table 11-9 Determination of Magnitude of Change – Air Quality
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May 2014
Table 11-10 Significance of Effects
Table 11-11 Ambient Data from Local Authority Secondary Sources
Table 11-12 Historic Ambient NO2 Monitoring Data
Table 11-13 Defra Mapped Background Data (1km grid squares)
Table 11-14 Primary Diffusion Tube Monitoring Locations
Table 11-15 Mean monitored Concentrations, 4 June - 30 Sept 2013 (µg/m3)
Table 11-16 Derived Baseline Concentrations (µg/m3)
Table 11-17 Predicted Baseline NOx Concentrations and Nitrogen Deposition Rates
at the Severn Estuary, 2019
Table 11-18 Summary of Construction Phase Dust Effects
Table 12-1 Relevant Scoping Opinion Responses to Noise and Vibration
Table 12-2 Construction Noise Thresholds at nearby Residential Dwellings
Table 12-3 Significance Criteria for Construction Noise
Table 12-4 Guidance Effects of Vibration for Human Response
Table 12-5 Significance Criteria for Operational Noise
Table 12-6 Scheme for Assessment of Changes in Road Traffic Noise Levels
Table 12-7 Free-field Ambient Noise Levels during Good Weather Conditions
Table 12-8 Observations during the Baseline Monitoring
Table 12-9 Threshold Values at Selected Receptors
Table 12-10 Predicted Free-Field Construction Noise Levels
Table 12-11 Difference between Predicted Construction Noise Level and Threshold Value
Table 12-12 Predicted Free-Field Daytime Construction Noise Levels associated with the
Cooling Water Pipeline Construction
Table 12-13 Predicted Noise Increases due to Construction Traffic
Table 12-14 Predicted Operational Noise Levels
Table 12-15 BS 4142 Assessment with 5dB Penalty – Single Shaft Configuration
Table 12-16 BS 4142 Assessment with 5dB Penalty – Multi Shaft Configuration
Table 12-17 Predicted Operational Noise Levels at Chittening Warth prior to Additional
Mitigation
Table 12-18 BS 4142 Assessment with No Penalty – Single Shaft
Table 12-19 BS 4142 Assessment with No Penalty – Multi Shaft
Table 12-20 Predicted Operational Noise Levels at Chittening Warth – with Mitigation
Table 12-21 Summary of Residual Effects
Table 13-1 Relevant Scoping Opinion Responses
Table 13-2 Criteria to determine Magnitude of Change
Table 13-3 Description of Significance of Effects
Table 13-4 Historical Land Use within the Proposed Development Site and Other DCO
Land for Electrical Connection
Table 13-5 Historical Development of Land Surrounding the Proposed Development Site
and Other DCO Land for the Electrical Connection
Table 13-6 Summary of Ground Stability Hazards for the Proposed Development Site and
Electrical Connection
Table 13-7 Summary of Site Geological Strata under the Proposed Development Site
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Table 13-8 Summary of Ground Stability Hazards within the Cooling Water Pipeline
Corridor
Table 13-9 Proposed Development Site Environmental Sensitivity
Table 13-10 Potential Sources, Pathways and Receptors for Consideration during the Site
Preparation and Construction Phases
Table 13-11 Summary of Residual Effects (post-mitigation)
Table 13-12 Construction Phase Cumulative Issues
Table 14-1 Relevant Scoping Opinion Responses
Table 14-2 Derivation of Importance of Water Resource
Table 14-3 Derivation of Magnitude of Change
Table 14-4 Derivation of Effect Significance
Table 14-5 Summary of Site Geological Strata
Table 14-6 Summary of Surface and Groundwater Receptors
Table 14-7 Summary of Risk Posed by all Flood Sources
Table 14-8 Residual Effect Significance for Water Quantity and Quality during
Construction Phase (Temporary)
Table 14-9 Residual Effect Significance for Water Quantity and Quality during Operation
Phase (Permanent)
Table 14-10 Construction Phase Effect on Flood Risk (Temporary)
Table 14-11 Operation Phase Effect on Flood Risk (Permanent)
Table 15-1 Scoping Opinion Responses Relevant to Archaeology and Cultural Heritage
Table 15-2 Criteria for Establishing the Importance of Heritage Assets
Table 15-3 Criteria for Establishing the Magnitude of Change on a Cultural Heritage Asset
Table 15-4 Matrix for Establishing Overall Significance of Effect
Table 15-5 Scheduled Monuments, Registered Parks and Gardens and Grade I and II*
listed buildings within 5km of the DCO Site
Table 15-6 Summary of Cultural Heritage Residual Effects
Table 16-1 Relevant Scoping Opinion Responses
Table 16-2 Valuation of Ecological Receptors
Table 16-3 Magnitude of Change
Table 16-4 Classification of Effects
Table 16-5 Definitions of Effects
Table 16-6 Habitat Potential for Protected Species and Other Fauna within the Proposed
Development Site
Table 16-7 Resource Evaluation
Table 16-8 Value of Ecological Receptors under Future Baseline Conditions
Table 16-9 Summary of Residual Effects
Table 16-10 Proposed Survey Requirements for the Final ES
Table 17-1 Classification of Landscape and Visual Effects
Table 17-2 Description of Landscape and Visual Effects
Table 17-3 Summary of Local Landscape Character
Table 17-4 Visual Receptors and Representative Views
Table 18-1 Total footprint emissions
Table 19-1 Relevant Scoping Opinion Responses
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May 2014
Table 19-2 Scale of Health Effect
Table 19-3 Health indicator data for, England, South Gloucestershire and Bristol
Table 19-4 Life expectancy from birth
Table 19-5 ICNIRP Reference Levels vs Typical Ground-level UK Field Levels from
Overhead Power Lines
Table 19-6 Summary of Residual Effects (post-mitigation)
Table 21-1 Summary of Demolition, Construction and Operational Residual Effects
Plates
Plate 3-1 Photograph 1 from the centre of the Proposed Development Site, facing West
towards Seabank 1 & 2 [Date taken, 01/07/2013]
Plate 3-2 Photograph 2 from the Centre of the Generating Station Site, facing West
towards Seabank 1 & 2 [Date taken, 01/07/2013]
Plate 3-3 Photograph 3 from the Generating Station Site, facing Northeast towards the
redundant railway tracks. [Date taken, 01/07/2013]
Plate 3-4 Photograph 4 from the Generating Station Site, facing Southeast and showing
the existing trees [Date taken, 01/07/2013]
Plate 3-5 Photograph 5 from the CCR Site adjacent to the Red Rhine, facing East [Date
taken, 30/08/2012]
Plate 3-6 Photograph 6 from the Centre of the CCR Site, facing North [Date taken,
30/08/2012]
Plate 3-7 Photograph 7 showing the connection between the Proposed Development
Site and Seabank 1 & 2 [Date Taken 20 February 2013.]
Plate 3-8 Photograph 8 showing the entrance of Seabank 1 & 2 Site [Date Taken 20
February 2013]
Plate 3-9 Photograph 9 of Seabank 400kV Substation [Date Taken 20 February 2013]
Plate 3-10 Photograph 10 showing corner of Chittening Road and Severn Road [Date
Taken 11 November 2013]
Plate 3-11 Photograph 11 showing the corner of Smoke Lane and Chittening Road [Date
Taken 04/09/2013]
Plate 3-12 Photograph 12 showing footpath facing west running adjacent to the railway
[Date Taken 04/09/2013
Plate 3-13 Photograph 13 showing culvert facing south [Date Taken 04/09/2013]
Plate 3-14 Photograph 14 – Facing north across Popular Way East [Date Taken
04/09/2013]
Plate 3-15 Photograph 15 – Facing north from the Bristol WWTW Entrance [Date Taken
04/09/2013]
Plate 4-1 Single and Multi Shaft Arrangements
Plate 5-1 Estimated Personnel Onsite during Construction (Post Enabling Works)
Plate 9-1 Profile of Construction Employment (excluding enabling works)
Plate 10-1 Average Weekday Automatic Traffic Counts Results on the A403
Plate 10-2 Average Weekend Automatic Traffic Counts Results on the A403
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May 2014
Plate 10-3 Traffic Counts Results at the Junction of Severn Road / A403 / Chittening
Road on Wednesday 14 November 2013
Plate 19-1 Source Pathway
Volume II - Appendices
Appendix A – Scoping Report and Scoping Opinion
Appendix B – Electronic Interference Assessment
Appendix C – Construction Environmental Management Plan
Appendix D – Planning Policy
Annex D1 - Socio-economic Legislation and Planning Policy Context
Annex D2 - Planning Policy Legislation and Planning Policy Context
Annex D3 - Air Quality Legislation and Planning Policy Context
Annex D4 - Noise and Vibration Legislation and Planning Policy Context
Annex D5 - Ground Conditions Planning Legislation and Policy Context
Annex D6 - Archaeology Legislation and Planning Policy Context
Annex D7 - Flood Risk, Hydrology and Water Resources Legislation and Planning
Policy Context
Annex D8 - Ecology Legislation and Planning Policy Context
Annex D9 - Landscape and Visual Legislation and Planning Policy Context
Annex D10 - Sustainability Legislation and Planning Policy Context
Appendix E – Traffic and Transport
Annex E1 – Meeting Notes
Annex E2 – Accident Data
Annex E3 – Trip Generation and Distribution
Annex E4 - Contractor Experience
Appendix F – Air Quality
Appendix G – Noise and Vibration
Appendix H – Archaeology
Annex H1 – Baseline Data
Annex H2 – Seabank Geotechnical Monitoring
Annex H3 – Figures
Appendix I – Ground Conditions
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May 2014
Annex I1 – Waste Facilities
Annex I2 – Proposed Development Site Photographs
Annex I3 – Site Photographs of the Other DCO Land
Annex I4 – Phase II Geotechnical and Contamination Assessment
Appendix J – Flood
Annex J1 – Modelling Report
Annex J2 – Cumulative Impacts
Annex J3 – Topographic Data
Annex J4 – Proposed Development
Annex J5 – Sequential Tests
Annex J6 – Runoff Calculations
Annex J7 – Breach Results
Appendix K – Ecology
Annex K1 – HRA
Annex K2 – Phase 1 Habitat Survey Report
Annex K3 – Bat Survey
Annex K4 – Wintering Bird Survey
Annex K5 – Breeding Bird Survey
Annex K6 – Amphibian Survey
Annex K7 – Reptile Survey
Annex K8 – Designated and Non Designated Sites
Annex K9 – Phase I Habitat Survey Report for the Cooling Water Pipeline Corridor
Appendix L – Land and Visual
Annex L1 – Baseline Landscape Character
Annex L2 – Baseline Visual Assessment
Annex L3 – Landscape Impact Assessment
Annex L4 – Landscape Impact Assessment
Appendix M – Climate Change Impact Assessment
Appendix N – CHP Assessment
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May 2014
Figures
Volume III – Figures.
Figure 1-1 Location of the Proposed Development Site
Figure 3-1 DCO Site and Development Land Parcels
Figure 3-2 Aerial Photograph of the Proposed Development Site
Figure 3-3 Location of Existing Services within the Proposed Development Site
Figure 3-4a Aerial View of the DCO Site and its Surrounds (Drawing 1 of 3)
Figure 3-4b Aerial View of the DCO Site and its Surrounds (Drawing 2 of 3)
Figure 3-4c Aerial View of the DCO Site and its Surrounds (Drawing 3 of 3)
Figure 3-5 Environmental Constraints
Figure 4-1a Development Parcels (Drawing 1 of 2)
Figure 4-1b Development Parcels (Drawing 2 of 2)
Figure 4-2 Indicative Maximum Layout of the Proposed Development – Single-Shaft
Configuration
Figure 4-3 Indicative Maximum Layout of the Proposed Development – Multi-Shaft
Configuration
Figure 4-4 Maximum Elevations of the Proposed Development – Single Shaft
Configuration
Figure 4-5 Maximum Elevations of the Proposed Development – Multi-Shaft
Configuration
Figure 4-6 Indicative 3D Visualisations of the Proposed Development Site
Figure 4-7 Access During Operation
Figure 5-1 Extend of Expected Land Raising
Figure 5-2 Laydown and Assess during Construction
Figure 5-3 Trenching Methods
Figure 5-4 Indicative Drawing of an Above Ground Electrical Cable Rack
Figure 5-5 Example Horizontal Directional Drilling (HDD)
Figure 6-1 Preliminary Indicative Layout, Including CCS Technology - April 2012
Figure 6-2 Interim Indicative Layout of the Proposed Development - March 2013
Figure 6-3 Interim Indicative Layout of the Proposed Development - August 2013
Figure 7-1 Cumulative Developments
Figure 10-1 Traffic Survey Locations
Figure 10-2 Crossing Points for the Proposed Route for Cooling Water Pipeline over
Roads and Public Rights of Way
Figure 11-1 Diffusion Tube Monitoring Locations
Figure 11-2 Modelled Mean Annual NOx Process Concentrations
Figure 12-1 Noise Monitoring and Receptor Locations
Figure 13-1 Distances from Seabank Substation
Figure 14-1 Significant Water Features and Catchment Boundary Map
Figure 15-1 Zone of Theoretical Visibility for the Proposed Development Site
Figure 15-2 HER Assets within 1km of the Proposed Development Site
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Figure 15-3a HER Assets within 1km of the Proposed Cooling Water Pipeline Corridor
Figure 15-3b HER Assets within 1km of the Proposed Cooling Water Pipeline Corridor
Figure 15-4 Location of Previous Investigations
Figure 15-5 Location of Previous Geotechnical Investigations
Figure 15-6 Geotechnical Transect from Previous Investigations
Figure 15-7a Geophysical Survey Results (2013)
Figure 15-7b Geophysical Survey Results with Single-Shaft Layout Overlaid
Figure 15-7c Geophysical Survey Results with Multi-Shaft Layout Overlaid
Figure 15-8 Location of Geotechnical Investigations
Figure 15-9 Geotechnical Transect from 2013 Investigations
Figure 15-10 Designated Assets within the 5km Study Area
Figure 15-11 Locations of Potential Below Ground Impacts (Single-Shaft)
Figure 15-12 Locations of Potential Below Ground Impacts (Multi-Shaft)
Figure 15-13a-e Areas of Previous Disturbance within the Other DCO Land
Figure 16-1 Statutory Nature Conservation Sites within 10km
Figure 16-2 Non-Statutory Nature Conservation Sites within 1km
Figure 16-3 Phase I Habitat Map Including BAP Habitats
Figure 17-1 Site Context and Registered Parks and Gardens
Figure 17-2 Topography
Figure 17-3 Site Character
Figure 17-4 Site Character Photographs A&B
Figure 17-5 Site Character Photographs C&D
Figure 17-6 Local Landscape Character Areas
Figure 17-7 Zones of Theoretical Visibility
Figure 17-8 Location of Representative Views and Photomontages
Figure 17-9 Representative Views 1&2
Figure 17-10 Representative Views 3&4
Figure 17-11 Representative Views 5&6
Figure 17-12 Representative Views 7&8
Figure 17-13 Representative Views 9&10
Figure 17-14 Representative View 11
Figure 17-15 Preliminary Landscape and Biodiversity Masterplan
Figure 17-16 Photomontage View 4 – Existing View
Figure 17-17 Photomontage of the Proposed Development from View Point 4, based on
a Single-Shaft configuration in Year 1
Figure 17-18 Photomontage of the Proposed Development from View Point 4, based on
a Single-Shaft configuration in Year 15
Figure 17-19 Photomontage of the Proposed Development from View Point 4, based on
a Multi-Shaft configuration in Year 1
Figure 17-20 Photomontage of the Proposed Development from View Point 4, based on
a Multi-Shaft configuration in Year 15
Figure 17-21 Photomontage View 10 – Existing View
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Figure 17-22 Photomontage of the Proposed Development from View Point 10, based on
a Single-Shaft configuration in Year 1
Figure 17-23 Photomontage of the Proposed Development from View Point 10, based on
a Single-Shaft configuration in Year 15
Figure 17-24 Photomontage of the Proposed Development from View Point 10, based on
a Multi-Shaft configuration in Year 1
Figure 17-25 Photomontage of the Proposed Development from View Point 10, based on
a Multi-Shaft configuration in Year 15
Figure 17-26 Photomontage of View Point 11 – Existing View
Figure 17-27 Photomontage of the Proposed Development from View Point 11, based on
a Single-Shaft configuration in Year 1
Figure 17-28 Photomontage of the Proposed Development from View Point 11, based on
a Single-Shaft configuration in Year 15
Figure 17-29 Photomontage of the Proposed Development from View Point 11, based on
a Multi-Shaft configuration in Year 1
Figure 17-30 Photomontage of the Proposed Development from View Point 11, based on
a Multi-Shaft configuration in Year 15
Seabank 3
PEI Report – Chapter 1 Introduction
1. Introduction
1.1. Background
1.1.1. This ‘Preliminary Environmental Information Report’ (PEI Report) has been prepared on behalf of SSE Seabank Land Investments Limited (the Applicant) in support of a proposed application that will be made to the Secretary of State (for Energy and Climate Change) under Section 37 of the Planning Act 2008 (Ref. 1-1), seeking an ‘Order’ granting Development Consent (a Development Consent Order, or DCO).
1.1.2. The DCO would provide the necessary authorisations and consents for the construction and operation of a generating station of up to 1,400 megawatts net electrical output capacity (MWe) (the ‘Proposed Development’) and associated infrastructure.
1.1.3. The Proposed Development is located on land adjacent to the existing Seabank 1 & 2 generating station in Severnside, Bristol, within the administrative boundary of South Gloucestershire Council (SGC). Elements of the Associated Development, in particular the proposed cooling water pipeline and electrical connection are situated within the administrative boundary of Bristol City Council (BCC).
1.2. The Applicant
1.2.1. The Applicant is SSE Seabank Land Investments Limited (SSE), which is a wholly owned subsidiary of SSE Generation Ltd.
1.2.2. SSE is one of the UK’s leading energy companies and the largest non-nuclear electricity generators, operating a diverse portfolio across the UK and Ireland. SSE is also a 50% shareholder of Seabank Power Ltd, which is the company that currently operates the existing Seabank 1 & 2 generating station.
1.2.3. Details of assets operated by SSE can be found at www.sse.com.
1.3. Location of the Proposed Development
1.3.1. The Proposed Development is known as ‘Seabank 3’ and is located on land immediately adjacent to the existing Seabank 1 & 2 generating station, approximately 5 kilometres (km) northeast of Avonmouth and 10km west of Bristol in an area called Crook’s Marsh in Severnside, as illustrated in Figure 1-1 (Volume III – Figures of this Report).
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PEI Report – Chapter 1 Introduction
1.3.2. The proposed application site to which the DCO Application will apply (referred to in the remainder of this report as the ‘DCO Site’) comprises an area of approximately 38 hectares (ha) and constitutes:
• An area within which the proposed generating station and Carbon Capture Ready (CCR) sites will be situated (referred to together as the ‘Proposed Development Site’). The Proposed Development Site is approximately 19ha and lies wholly within the SGC administrative boundary and is fully owned by the Applicant; and
• Other DCO Land. This includes all Associated Development beyond the Proposed Development Site, which comprises the proposed electrical connection and a cooling water pipeline. This covers approximately 19ha and is the only part of the DCO Site that is situated within the administrative boundary of BCC.
1.3.3. A more comprehensive description of the DCO Site and the terminology mentioned above is presented in Chapter 3: The Site and Its Surroundings of this PEI Report.
1.4. The Proposed Development
1.4.1. The Proposed Development constitutes a generating station with up to 1,400MW net electrical output capacity. This comprises up to two Combined Cycle Gas Turbine (CCGT) units with a total capacity of up to 1,400MWe, plus peaking plant units with a capacity up to 240MWe. The electrical capacity of the CCGTs will be reduced if the peaking plant is built to ensure the total output capacity of the Proposed Development does not exceed 1,400MW.
1.4.2. The Proposed Development will include the installation of a hybrid cooling water system, administrative buildings and associated infrastructure, as well as Associated Development within the Proposed Development Site such as pipework, control rooms, water supply, storage and purification equipment, gas receiving equipment, grid connection infrastructure and supporting site infrastructure. The proposed cooling water pipeline and electrical connection are also Associated Development but referred to hereafter as ‘associated infrastructure’ so to distinguish these from the Proposed Development Site.
1.4.3. A more comprehensive description of the Proposed Development is presented in Chapter 4: Project Description of this PEI Report.
1.4.4. The need for the Proposed Development is outlined in Chapter 6: Project Need and Alternatives of this PEI Report, which also describes the alternatives that have been considered during the evolution of the Proposed Development.
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PEI Report – Chapter 1 Introduction
1.5. Structure of this PEI Report
1.5.1. The following provides a summary of each document that forms the PEI Report:
• PEI Volume I – Main PEI Report: This document is the main body of the PEI Report, divided into a number of background and technical chapters supported with figures and tabular information for clarity of reading.
• PEI Volume II – Technical Appendices: This document comprises survey data, technical reports, and background information supporting the assessments within the PEI Report.
• PEI Volume III – Figures: This document contains the figures referred to in Volume I.
• PEI Non-Technical Summary: This is a separate document providing a concise summary of the Proposed Development and associated infrastructure, alternative designs that were considered, and the environmental effects and mitigation measures in plain, non-technical language.
1.5.2. A list of the PEI Report chapters and Appendices is presented in Chapter 7: Assessment Methodology.
1.6. The Purpose of the Preliminary Environmental Information (PEI) Report
1.6.1. The purpose of this PEI Report is outlined in The Planning Inspectorate Advice Note 7: Environmental Impact Assessment: Screening, Scoping and Preliminary Environmental Information (Version 4) (Ref. 1-2), where it is described as a document to “enable the local community to understand the environmental effects of the proposed development so as to inform their responses regarding the proposed development”.
1.6.2. PEI is defined in the Infrastructure Planning (Environmental Impact Assessment) Regulations 2009 (Ref. 1-3) as “information referred to in Part 1 of Schedule 4 (information for inclusion in environmental statements) which (a) has been compiled by the applicant; and (b) is reasonably required to assess the environmental effects of the development (and of any associated development)”.
1.6.3. In order to enable consultees to develop “an informed view of the project” this report presents preliminary findings of the environmental assessments undertaken to date. This allows consultees the opportunity to comment on the Proposed Development and associated infrastructure, the assessment process and preliminary findings prior to the finalisation of the Environmental Statement
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Seabank 3
PEI Report – Chapter 1 Introduction
(ES). The Applicant is actively seeking the views of consultees on the information contained within this report, and there is opportunity within the process for both the Environmental Impact Assessment (EIA) and the project design to take account of any comments received.
1.6.4. It should be noted that this PEI Report does not constitute a full ES, but rather presents the assessments completed as part of the EIA process to date. The various assessments are at differing stages of completion and any gaps are highlighted where relevant. It is considered that the information presented in this PEI Report is sufficient to enable consultees to develop an informed view of the project. Following the formal consultation process, and once the design is further developed this report will be developed into a final ES taking into consideration comments raised during the consultation.
1.6.5. The information presented in this report depicts the extent of the environmental assessment work undertaken to date based upon the information available. The design will continue to evolve and some baseline data are not yet available, although this is not considered to be material to understanding the potential effects of the Proposed Development and associated infrastructure. As such it is not possible to present a complete impact assessment on each environmental topic, but instead this report depicts what the likely effects are, based upon current information, and what work will be undertaken in the future to complete the individual assessments. Presentation of PEI in this way also allows the EIA process to take account of comments received during the formal consultation process.
1.6.6. Where data are missing or there are assumptions made for this preliminary assessment, this is made clear in the text of the report and the information will be made available in the final ES. The information provided within this report has been compiled in order to seek comments on the Proposed Development and associated infrastructure from the consultees. Comments will be taken into consideration during the final stages of the EIA process and project design.
1.7. Location of Information within the PEI Report
1.7.1. The EIA Regulations (Schedule 4, Part 1) (Ref. 1-3) identify information that is “reasonably required to assess the environmental effects of the development and which the applicant can, having regard in particular to current knowledge and methods of assessment, reasonably be required to compile”. This information together with its location within the PEI Report is presented in Table 1-1.
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Seabank 3 PEI Report – Chapter 1 Introduction
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Table 1-1: Location of Information within the PEI Report
Specified Information (EIA Regulations)
Location Within PEI Report
1 Description of the development, including in particular: -
a) A description of the physical characteristics of the whole development and the land use requirements during the construction and operational phases;
Chapter 4: Project Description
b) A description of the main characteristics of the production processes, for instance, nature and quantity of the materials used; and
Chapter 4: Project Description
c) An estimate, by type and quantity, of expected residues and emissions (water, air and soil pollution, noise, vibration, light, heat, radiation, etc) resulting from the operation of the proposed development.
Chapters 9-19
2 An outline of the main alternatives studied by the applicant and an indication of the main reasons for its choice, taking into account the environmental effects.
Chapter 6: Project Need and Alternatives
3 A description of the aspects of the environment likely to be significantly affected by the development, including, in particular, population, fauna, flora, soil, water, air, climatic factors, material assets, including the architectural and archaeological heritage, landscape and the inter-relationship between the above factors.
Chapters 9-19
4 A description of the likely significant effects of the development on the environment, which should cover the direct effects and any indirect, secondary, cumulative, short, medium and long-term, permanent and temporary, positive and negative effects of the development, resulting from:
Chapters 9-19
a) the existence of the development; Chapters 9-19
b) the use of natural resources; and Chapters 9-19
c) the emission of pollutants, the creation of nuisances and the elimination of waste.
Chapter 11: Air Quality
Chapter 12: Noise and Vibration
5 A description of the measures envisaged to prevent, reduce and where possible, off set any significant adverse effects on the environment.
Chapters 9-19
6 A non-technical summary of the information provided under paragraphs 1 to 5 of this Table.
Non-Technical Summary
7 An indication of any difficulties (technical deficiencies or lack of know-how) encountered by the applicant in compiling the required information.
Chapter 7: Assessment Methodology
1.8. Other Required Consents
1.8.1. The Proposed Development and associated infrastructure will require an
Environmental Permit under the Environmental Permitting (England and Wales)
Regulations 2010, as amended (Ref. 1-4). This Permit will be subject to
determination by the Environment Agency (EA). It is intended that an application
for an Environmental Permit will be submitted to the EA within similar timescales
as the DCO Application, and it is noted that there are overlaps in consideration
between the two consenting regimes. This PEI Report has considered all
potential environmental effects of the Proposed Development and associated
infrastructure (as will the final ES), and will therefore also inform and support the
Environmental Permitting process.
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PEI Report – Chapter 1 Introduction
1.8.2. Additional consents may be required to support the Proposed Development and those that are to be covered by the DCO will be highlighted in the application accordingly.
1.9. References
Ref. 1-1 HMSO, IPC (2008); The Planning Act, Infrastructure Planning Commission (IPC)
Ref. 1-2 Planning Inspectorate (2013); Advice Note 7: Environmental Impact Assessment: Screening, Scoping and Preliminary Environmental Information (Version 4)
Ref. 1-3 HMSO (2009); Infrastructure Planning (Environmental Impact Assessment) Regulations
Ref. 1-4 Environmental Permit under the Environmental Permitting (England and Wales) Regulations 2010
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Seabank 3 PEI Report – Chapter 2 The DCO and EIA Processes
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2. The DCO and EIA Processes
2.1. Introduction
2.1.1. This chapter of the PEI Report outlines the purpose of PEI and the process
involved within the Application.
2.1.2. It also presents a review of the key issues raised by consultees during the
Scoping stage and indicates how and where these issues have been addressed
within this PEI Report.
2.2. DCO Process
2.2.1. The Proposed Development falls within the definition of a ‘Nationally Significant
Infrastructure Project’ (NSIP) under Section 14(1)(a) and Sections 15(2) of the
Planning Act 2008 (Ref. 2-1), as it is an onshore generating station within
England that will have a generating capacity greater than 50MW gross output. As
such there is a requirement to submit an application for development consent for
the Proposed Development to the Planning Inspectorate.
2.2.2. As a NSIP project, the Applicant is required to seek a DCO to build the Proposed
Development, under Section 31 of the Planning Act. The DCO Application will be
prepared in accordance with Section 37 of this Act and secondary legislation,
including The Infrastructure Planning (Environmental Impact Assessment)
Regulations 2009 (as amended) (‘EIA Regulations’) (Ref. 2-2) and Regulation 5
(2)(a) of the Infrastructure Planning (Applications: Prescribed Forms and
Procedure) Regulations 2009 (‘APFP Regulations’) (Ref. 2-3).
2.2.3. The DCO Application will be submitted to the Planning Inspectorate’s National
Infrastructure Directorate who will examine the application and make
recommendations to the Secretary of State, who in turn will determine whether or
not a DCO should be granted for the Proposed Development and associated
infrastructure. Development Consent is granted by means of a parliamentary
‘Order’ (the DCO).
2.2.4. A DCO can grant planning permission and a range of other consents and
authorisations for the ‘Principal Development’ and ‘Associated Development’. The
latter is either to support the construction or operation of or help to address the
impacts of the former, such as the proposed cooling water pipeline for example.
2.2.5. It is currently anticipated that the Application for Development Consent will be
submitted in Quarter 4 (Q4) of 2014, although this may be subject to change.
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2.3. EIA Development
2.3.1. As outlined above the proposals fall within the definition of a NSIP under the
definition of the Planning Act 2008 (Ref 2-1). It is also a ‘Schedule 1’
development under Schedule 1 (2)(a) of the EIA Regulations (Ref. 2-2) as it
constitutes “Thermal power stations and other combustion installations with a
heat output of 300 megawatts or more”. The Proposed Development is therefore
classified as a mandatory EIA development and as such an ES needs to be
prepared to comply with the EIA Regulations.
Legislation and Guidance for EIA and Preparation of an ES
2.3.2. The PEI Report has been (and the final ES will be) prepared in accordance with
applicable legislation, guidance, and case law for the preparation of such
documents as outlined below.
2.3.3. The Planning Act 2008 (Ref. 2-1) enables the Secretary of State to designate
National Policy Statements (NPSs), to set out national policy in relation to
specified descriptions of nationally significant infrastructure development. A
number of NPSs relating to energy infrastructure (including technology specific
NPSs) were designated by the Secretary of State for the Department of Energy
and Climate Change (DECC) in July 2011.
2.3.4. As outlined in Chapter 8: Planning Policy Context, the NPSs that are relevant to
the Proposed Development are the:
• Overarching NPS for Energy (EN-1) (Ref. 2-4);
• Fossil Fuel Electricity Generating Infrastructure NPS (EN-2) (Ref. 2-5);
and
• NPS for Electricity Networks Infrastructure (EN-5) (Ref. 2-6).
2.3.5. In addition to the NPS, particular advice on the EIA process for DCO applications
is provided by several advice notes published by the Planning Inspectorate,
whilst further useful advice is afforded by Planning Practice Guidance (Ref 2-7)
and the guidance contained within the Department for Communities and Local
Government (DCLG) paper ‘Environmental Impact Assessment: A guide to good
practice and procedures, a consultation paper’ (2006) (Ref 2-8).
2.3.6. In preparing this PEI Report (in line with the regulations as it forms part of the EIA
process), reference has been made to the following policies and guidance:
• The Planning Act (2008) (Ref. 2-1);
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• Infrastructure Planning (Environmental Impact Assessment)
Regulations (2009) (Ref. 2-2);
• Planning Inspectorate - Advice Note 3: EIA Consultation and
Notification; July 2013 (Ref. 2-9);
• Planning Inspectorate - Advice Note 7: Environmental Impact
Assessment, Screening and Scoping; July 2013 (Ref. 2-10);
• Planning Inspectorate - Advice Note 9: Rochdale Envelope; July 2013
(Ref. 2-11);
• DECC Overarching NPS for Energy (EN-1) (2011) (Ref. 2-4);
• DECC NPS for Fossil Fuel Electricity Generating Infrastructure (EN-2)
(2011) (Ref. 2-5);
• DECC NPS for Electricity Networks Infrastructure (EN-5) (2011) (Ref.
2-6);
• DCLG Planning Practice Guidance (Ref. 2-7);
• DCLG 2006. Environmental Impact Assessment: A guide to good
practice and procedures (Ref. 2-8);
• Institute of Environmental Management and Assessment (IEMA) 2006.
Guidelines for Environmental Impact Assessment (Ref. 2-12);
• Environment Agency 2002 – Scoping Guidance on the Environmental
Impact Assessment of Projects (Ref. 2-13).
2.4. The EIA Scoping Exercise
2.4.1. Before preparing an EIA, an applicant has the opportunity to ask the Secretary of
State for a formal written opinion on the information to be included in the ES. This
is known as a ‘Scoping Opinion’. By this means key stakeholder engagement and
consultation can begin at an early stage in the process.
2.4.2. EIA scoping refers to the activity of identifying those environmental aspects that
may be significantly affected by the construction and operation of the Proposed
Development and associated infrastructure and how those effects are to be
assessed within the EIA process. In addition, it presents the justification for the
exclusion of those aspects that are considered will be unaffected by the
Proposed Development. In doing so, the potential significance of effects
associated with each environmental aspect becomes more clearly defined,
resulting in the identification of priority issues to be addressed in the EIA. This
process therefore focuses the assessment on the critical issues that require
assessment within the consenting process.
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2.4.3. The issues to be addressed within the ES were identified in the EIA Scoping
Report submitted to the Planning Inspectorate on 12 February 2013 (Ref. 2-14)
together with a request for an EIA Scoping Opinion under Regulation 8(1) of the
EIA Regulations. This Scoping Report was developed following initial consultation
with a number of statutory consultees and was informed by experience from the
Seabank 1 & 2 station. A Scoping Opinion was received on 19 March 2013 (Ref.
2-15). Key issues raised in the Scoping Opinion relevant to the technical
assessments are summarised at the start of each technical chapter in this report
(Chapter 9-19 of this PEI Report) and have been taken into account during the
EIA process and in the completion of this PEI Report.
2.4.4. Formal EIA Scoping Responses received from the Secretary of State on the EIA
Scoping Report are presented in Appendix A, Volume II of this PEI Report.
2.4.5. The topics included within this PEI Report reflect the topics that will be presented
within the final ES. An additional chapter has been included in this report
compared with the suggested structure presented in the Scoping Report following
the response from the Health Protection Agency (HPA), which recommended that
“health impacts are consolidated into a separate chapter of the ES or carried out
as a separate HIA”.
2.4.6. The Scoping Opinion from the Secretary of State also recommends a separate
chapter on Infrastructure and Utilities, to assess the effect of the Proposed
Development on 3rd party assets. The need for a separate chapter has largely
been superseded by design avoidance measures however, which are in-built into
the Proposed Development. Sections 3.3 and 3.6 of Chapter 3: The Site and Its
Surroundings present an overview of the utilities and infrastructure onsite and in
the surrounding area. Sections 5.2 and 5.3 of Chapter 5: Enabling Works and
Construction discuss the diversion of existing infrastructure and services within
the Proposed Development Site and special crossing of any infrastructure and
services required by the proposed cooling water pipeline. Any residual effects on
environmental parameters are discussed within the individual technical chapters.
2.4.7. Where it has not yet been possible to complete an assessment for a topic to date,
the topic is still included in this report, setting out details of what will be assessed
with an initial prediction of the likely effects.
2.5. Non Key Issues
2.5.1. The Scoping process concluded that the following technical topics are not
relevant to the EIA for the Proposed Development and could be scoped-out from
further evaluation. It is therefore intended that these topics will not be assessed
within the ES, though comments on these topics are invited from consultees.
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Aviation
2.5.2. Consultation with the Civil Aviation Association (CAA) during scoping confirmed
that there is no legislative requirement to illuminate structures or obstacles below
150m in height. However, the CAA suggested contacting the surrounding
aerodrome license holders regarding safeguarding. This includes the Bristol
International Airport (Lulsgate) and the former Filton Airport (currently closed but
with emergency helicopters operating out of this site).
2.5.3. Bristol International (Lulsgate) confirmed that the Proposed Development falls
outside the airport’s formally safeguarded area of 15km; therefore it does not
have safeguarding concerns with the Proposed Development.
2.5.4. Emergency helicopter services (Police and Ambulance) agreed that there is no
legal requirement to illuminate the structures for the height of the proposed
stacks (up to 100m at the time of Scoping). However, due to the distance to Filton
Airport, both the Police and Ambulance Air Services consider it to be desirable to
have night time lighting and reasonable visual contrast of the stacks during
daylight hours.
2.5.5. In light of this feedback, the Proposed Development will incorporate low intensity
steady red aviation warning lighting and colour markings positioned as close to
the top of the stacks as practicable. This is further outlined in Chapter 4: Project
Description of this PEI Report and assessed in Chapter 17: Landscape and
Visual.
2.5.6. Bearing this in mind, it is not considered that an aviation assessment is required
for the PEI Report or final ES.
Electronic Interference
2.5.7. The Scoping Opinion from the Secretary of State agreed that Electronic
Interference effects could be scoped out of the EIA, providing that a screening
assessment was undertaken.
2.5.8. A screening assessment by ‘Tom Paxton’ Broadcasting Consultant indicates that
the Severnside area receives its preferred terrestrial signals from the Mendip
transmitter, sited about 34km due south of the Proposed Development Site. It is
therefore predicted that any 'shadow' (on electronic reception) cast by the
Proposed Development will lie to the north, in the direction of Severn Beach
village.
2.5.9. The nearest housing in this direction is almost exactly 1.5km away, at the
southern edge of Severn Beach. At this distance, it is not expected that the
shadows from main structures on Proposed Development Site would reach the
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Severn Beach village, and the stacks should not cause any interference due to
their relatively narrow width (which enables the signal to diffract around these
structures). Tom Paxton Broadcasting Consultant concluded that a full
assessment would not be necessary and the potential effects from electronic
interference can be considered insignificant/negligible.
2.5.10. A copy of the screening assessment is presented in Appendix A, Volume II of this
PEI Report.
Accidental Events/Health and Safety
2.5.11. The majority of emergency response plans and contingency measures will be
dealt with in the construction and Environmental Permits that will be required for
the construction and operation of the Proposed Development and associated
infrastructure. However, the potential for effects of air emissions on human health
are considered as part of the EIA and in this PEI Report.
Soils and Agriculture
2.5.12. The Proposed Development Site is not currently used for agricultural purposes
and lies within a wider employment area which benefits from planning
permissions for warehousing and distribution uses. It also has extant planning
permission for a range of industrial uses (excluding a generating station) as well
as being part of a wider area that has been allocated for a range of employment
uses including energy generation in the SGC Core Strategy (Ref. 2-17). It is
therefore not considered that an assessment of agricultural land use or its
potential for crop production is relevant to the Proposed Development Site.
2.5.13. Furthermore the Agricultural Land Classification Map South West Region (Ref. 2-
19) and Natural England MAGIC map (Post 1988 Agricultural Land Classification)
(Ref. 2-18) both classify the Proposed Development Site as predominantly
industrial use. The nearest agricultural land is classed as Grade 3b (Moderate
Quality) or 4 (Poor Quality); hence it is considered unlikely that the Proposed
Development would represent a significant loss of agricultural land.
2.6. Preliminary Environmental Information
2.6.1. As part of the EIA process, the assessment of the potential environmental effects
on the various potential receptors is on-going. The assessments are at various
stages depending on the information that is currently available and the extent of
any investigations or site surveys that have been undertaken to date. A number
of surveys are either underway or still to be commissioned.
2.6.2. When further data becomes available after the production of this report, it will be
used to further inform the assessments, as they are developed for the final ES.
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The information presented within this report is therefore in the form of initial
findings. This is subject to change should further data become available or upon
receipt of relevant consultation responses and any further changes arising
through the design process.
2.6.3. Each technical assessment that has been carried out highlights any current data
gaps and details the methodology that will be employed following receipt of the
relevant data.
2.6.4. Additional information received, along with the responses from the consultation
process, will be used to inform the design process and the final ES. Any changes
that arise between the production of this PEI Report and the final ES will be
highlighted and clearly explained within the final ES.
2.6.5. In particular, the description of baseline conditions in this PEI Report has been
based on the state of the Proposed Development Site as it was on 01 December
2013, which was valid at the time of drafting this report. The Site has undergone
noticeable change since this date, due to the introduction of a temporary access
route (haul road) for use by SITA to facilitate the construction of the Severnside
Energy Recovery Centre on land immediately west of the Proposed Development
Site, and also the construction of the Spine Access Road and new channel for
the Red Rhine along the northern boundary of the Proposed Development Site
on behalf of Severnside Distribution Land Ltd. A brief description of these other
developments is presented in Chapter 7: Assessment Methodology.
2.6.6. The site description and baseline conditions will be updated for the final ES, to
reflect the state of the Proposed Development Site at the point of submitting the
Application, or at an agreed point in time shortly beforehand. Any changes to the
predicted effects and mitigation measures due to the change in baseline
conditions would also be captured in the final ES.
2.7. Design Parameters Used within the DCO Application
2.7.1. A number of the detailed design aspects of the Proposed Development cannot be
fixed until the contract for the detailed design and construction of the Proposed
Development has been awarded. For example, the scale of the buildings within
the Proposed Development may vary depending upon the contractor appointed
and their specific selection and configuration of the plant and process equipment.
The design of the Proposed Development therefore needs to incorporate a
degree of flexibility to allow for such circumstances.
2.7.2. In order to ensure a robust assessment of the likely significant environmental
effects of the Proposed Development, the EIA will be undertaken adopting the
principles of the ‘Rochdale Envelope’ (Ref. 2-9). This will involve assessing the
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maximum and minimum parameters for the elements where flexibility needs to be
retained. Where this approach is applied to the specific aspects of the EIA this
has been confirmed within the relevant chapters of this PEI Report and will also
be confirmed within the relevant chapters of the ES that will report on the
complete findings of the EIA and form part of the DCO Application.
2.7.3. For the purposes of the assessments within this PEI Report, each chapter has
adopted a reasonable ‘worst-case’ scenario for its assessment. For the majority
of assessments, this worst-case will be based upon the maximum design
parameters, though it is recognised that the final design will be very unlikely to
utilise the maxima for every building as it depends on the plant selected and the
layout; therefore this is considered to be a highly conservative assumption. This
is discussed in Chapter 4: Project Description.
2.8. Consultation
2.8.1. The process of consultation is integral to the DCO Application and EIA processes
and important to the development of a comprehensive and balanced EIA of the
Proposed Development. The views of interested parties including key statutory
and non-statutory consultees serve to focus the environmental studies and to
identify specific issues, which require further investigation. Consultation is also an
on-going process, which enables mitigation measures to be incorporated into the
project design, thereby limiting adverse effects and enhancing benefits.
2.8.2. The Planning Act (Ref. 2-1) requires applicants for Development Consent to carry
out formal (statutory) consultation on their proposals prior to submitting an
application (during the pre-application stage).
2.8.3. Section 42 of the Planning Act requires an applicant to consult with ‘prescribed
persons’, which includes certain statutory consultees such as the EA and Natural
England (NE), relevant statutory undertakers, relevant local authorities, those
with an interest in the land, and those who may be affected by the development.
The PEI is generally provided to the ‘prescribed persons’ as part of the Section
42 consultation.
2.8.4. Section 47 requires an applicant to consult with the local community on the
development. Prior to this, the applicant must agree a Statement of Community
Consultation (SoCC) with the relevant local authority. The SoCC must set out the
proposed community consultation and, once agreed with the relevant local
authority, the SoCC notice must be published in local newspapers circulating
within the vicinity of the DCO Site. The community consultation must then take
place in accordance with the SoCC. It recommends that the PEI is made
available to the community and that it includes a non-technical summary. In
addition, Section 48 of the Act requires the applicant to publicise the proposed
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May 2014 Page 2-9
application in the prescribed manner in a national newspaper, The London
Gazette and local newspapers circulating within the vicinity of the land.
2.8.5. The consultation that the Applicant has undertaken to date and is in the process
of undertaking is summarised below:
• Informal consultation - this has encompassed a number of meetings
with SGC, BCC, NE, EA, Highways Agency (HA), English Heritage and
other relevant authorities and statutory consultees; informal
consultation with the local community within the vicinity of the DCO
Site from June 2013, including a number of public exhibitions; and
informal consultation with the relevant local authorities on the
preparation of the SoCC and the proposed community consultation for
Section 47. Comments received during the informal consultation will be
afforded the same weight as those received during the formal
consultation.
• EIA related consultation - this has taken place alongside the ‘informal
consultation’ and has included initial meetings and discussions with the
technical departments of the relevant local authorities and statutory
consultees mentioned above to inform early environmental assessment
work. Consultation was also undertaken during the preparation of the
EIA Scoping Report to form the basis of the application made to the
Planning Inspectorate for a Scoping Opinion. Further discussions were
held with relevant consultees following receipt of the Scoping Opinion
to inform the preparation of this PEI Report. EIA related consultation
will continue through the formal (statutory) consultation stage.
• Formal (statutory) consultation expected to be held in Spring 2014,
which will comprise:
o Section 42 consultation of ‘prescribed persons’;
o Section 47 consultation of the local community; and
o Section 48 publicity and related notification of those consulted by
the Planning Inspectorate during the EIA scoping process.
2.8.6. This PEI Report forms part of the information that is being provided for the
purposes of the formal (statutory) consultation pursuant to Sections 42, 47 and
48 of the Planning Act. It is intended to inform the ‘prescribed persons’ and local
community on the following:
• The extent of the environmental assessment work performed to date
on the Proposed Development and associated infrastructure;
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• Work that has been completed, or is underway, to address issues
raised during the informal consultation and EIA scoping stages that are
of relevance to the EIA process; and
• Any changes that have been made following the consultation
undertaken.
2.8.7. Responses received to the formal (statutory) consultation will be recorded
alongside those received through the informal consultation. The consultation that
has been undertaken and how this has informed the final design of the Proposed
Development and associated infrastructure will be fully documented within a
Consultation Report that will form part of the DCO Application.
2.8.8. All the information displayed at exhibitions is available via the website:
www.sse.com/seabank3.
2.9. PEI Report Availability
2.9.1. This PEI Report is available for viewing by the general public during normal office
hours at the offices of the Planning Department of SGC and BCC. Comments on
the planning application should be forwarded to the following address:
Jeffrey Penfold
The Planning Inspectorate
Temple Quay House
Temple Quay
Bristol
BS1 6PN
2.9.2. A copy is also being made available to view at the following addresses during a
public consultation period that is expected to be held in Spring 2014:
• Severn Beach Public Library / Post Office;
• Yate Public Library;
• Thornbury Library St Mary Street;
• The Patchway Hub;
• Bristol City Council City Office;
• Bristol City Council Customer Service Centre;
• Avonmouth Public Library;
• Sea Mills Public Library;
• Shirehampton Public Library; and
Seabank 3 PEI Report – Chapter 2 The DCO and EIA Processes
May 2014 Page 2-11
• Hendbury Public Library Crow Lane.
2.9.3. Further copies of all these reports, or further information on the Proposed
Development and associated infrastructure, can be obtained from the Applicant’s
website at: www.sse.com/seabank3
2.9.4. Printed copies of the full PEI Report and Technical Appendices can be
purchased for £350 (PEI Report £150, Technical Appendices £200), and
electronic copies on CD are available for free (or a fee of £5 each if requesting
more than 5 CDs) from:
Jade Fearon
SSE
Community Liaison Officer
FREEPOST SEABANK 3 CONSULTATION
2.10. References
Ref. 2-1. HMSO, IPC (2008); The Planning Act, Infrastructure Planning Commission (IPC)
Ref. 2-2. HMSO (2009); Infrastructure Planning (Environmental Impact Assessment) Regulations
Ref. 2-3. HMSO (2009); Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations
Ref. 2-4. DECC (2011) Overarching NPS for Energy (EN-1)
Ref. 2-5. DECC (2011) NPS for Fossil Fuel Electricity Generating Infrastructure (EN-2)
Ref. 2-6. DECC (2011) NPS for Electricity Networks Infrastructure (EN-5)
Ref. 2-7. DCLG (2014); Planning Practice Guidance. http://planningguidance.planningportal.gov.uk/blog/guidance/
Ref. 2-8. DCLG (2006); Environmental Impact Assessment: A guide to good practice and procedures.
Ref. 2-9. Planning Inspectorate (2013); Advice Note 3: EIA Consultation and Notification
Ref. 2-10. Planning Inspectorate (2013); Advice Note 7: Environmental Impact Assessment: Screening, Scoping and Preliminary Environmental Information (Version 4)
Ref. 2-11. Planning Inspectorate (2013); Advice Note 9: Rochdale Envelope
Ref. 2-12. IEMA (2006); ‘Guidelines for Environmental Impact Assessment’.
Ref. 2-13. Environment Agency (2002) Scoping Guidance on the Environmental Impact Assessment of Projects.
Ref. 2-14. URS Infrastructure & Environment UK Limited on behalf of SSE Generation Ltd (2013); ‘Seabank 3 EIA Scoping Report’.
Ref. 2-15. Planning Inspectorate (2013); ‘Formal Scoping Opinion regarding the Proposed Seabank 3 CCGT’.
Seabank 3 PEI Report – Chapter 2 The DCO and EIA Processes
May 2014 Page 2-12
Ref. 2-16. South Gloucestershire Council (2013) Core Strategy
Ref. 2-17. Natural England (2013) South West Region Agricultural Land Classification
Ref. 2-18. Natural England MAGIC map (2013) (Post 1988 Agricultural Land Classification)
Seabank 3
PEI Report – Chapter 3 The Site and Its Surroundings
3. The Site and its Surroundings
3.1. Introduction
3.1.1. This chapter provides an overview of the DCO Site and its surroundings, based on its status pre-01 December 2013 (as explained in Chapter 2: The DCO and EIA Process). A description of the project is presented in Chapter 4: Project Description.
3.1.2. The DCO Site comprises an area of approximately 38ha and constitutes the following two components:
1. The ‘Proposed Development Site’ - an area of approximately 19ha (illustrated on Figure 3-1, Volume III of this PEI Report) situated immediately east of the existing Seabank 1 & 2 station and wholly located within the administrative boundary of SGC. It is bound by the proposed SITA Severnside Energy Recovery Centre (SERC) to the northwest, beyond which is the Severn Estuary, approximately 400m to the west (an internationally designated Special Area of Conservation, Special Protection Area, Ramsar Site and Site of Special Scientific Interest), the former Terra Nitrogen and ICI site to the north which is now vacant land, an existing roundabout that will form part of the proposed Spine Access Road to the east (beyond which is grass fields), and grass fields and the Avonmouth LNG Storage Facility to the south. The administrative boundary of BCC forms the southern boundary of the Proposed Development Site.
The Proposed Development Site is further split into the following land parcels, as illustrated in Figure 3-1 (Volume III of this PEI Report). The areas overlap slightly, resulting in the sum of the three components being slightly greater than the 19ha Proposed Development Site.
• Generating Station Site: an area of approximately 7.4ha within the western part of the Proposed Development Site, within which the generating station and some Associated Development will be constructed. It excludes the land parcels described below.
• Utilities, Services and Landscaping Area: this is a 6.4ha area reserved for utilities connections, gas reception and landscaping, excluding the electrical connection and cooling water pipeline.
• CCR Site: an area of approximately 6.3ha within the eastern part of the Proposed Development Site which is reserved for the future retrofit of Carbon Capture Storage (CCS) plant should this be required. CCS is not part of this application; however this land will be retained for the installation of post combustion carbon capture,
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PEI Report – Chapter 3 The Site and Its Surroundings
cleaning and compression plant if the technology becomes viable. Should CCS be developed for the generating station at some point in the future, this would be subject to a new planning application. In accordance with the CCR requirements outlined by DECC, this land has been set aside in order to satisfy the Secretary of State that it can be used as and when installing CCS technology. The CCR Site will be used by construction contractors during the construction of the generating station, as described in Chapter 5: Enabling Works and Construction, and reinstated to grassland following its completion.
2. Other DCO Land: This includes all Associated Development (as defined by Section 115(2) of the Planning Act) beyond the Proposed Development Site, which consists of the proposed electrical connection and proposed cooling water pipeline. It covers approximately 19ha and is situated entirely within the administrative boundary of BCC.
3.1.3. The DCO Site and its land parcels outlined above are illustrated in Figure 3-1 (Volume III of this PEI Report). The Proposed Development Site and Other DCO Land are described separately below, in Sections 3.2 and 3.6 respectively.
3.2. The Proposed Development Site
3.2.1. The Proposed Development Site (‘the Site’) is situated within the Severn Estuary, approximately 5km northeast of Avonmouth and 10km west of Bristol in an area called Crook’s Marsh in Severnside, as illustrated in Figure 1-1, Volume III of this PEI Report. It is located entirely within SGC, with its southern boundary forming the administrative boundary with BCC.
3.2.2. The Site covers an area of approximately 19ha and is located on land immediately adjacent to the existing Seabank 1 & 2 CCGT Power Station within a predominantly industrial area. The River Severn lies approximately 400m to the west and the M49 motorway 1km to the east of the Site. The approximate National Grid Reference of the centre of the Proposed Development Site is (x,y) 354300, 182130.
3.2.3. The Proposed Development Site constitutes a relatively flat area of open, uneven grassland ranging in level between 5.5m and 7m above ordnance datum (AOD), with the existing access to the Proposed Development Site via Ableton Lane, from Severn Road.
3.2.4. Figure 3-2 (Volume III of this PEI Report) presents an aerial image of the Proposed Development Site. It shows that the Site is criss-crossed by several rhines (drainage channels) and ditches that flow into the Severn Estuary via the Red Rhine. The Red Rhine is the largest drainage channel within the Proposed
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PEI Report – Chapter 3 The Site and Its Surroundings
Development Site and one of the main rhines in this area, currently running in an east to west direction along the south of the CCR Site, and then through the centre of the Generating Station Site. There are proposals being developed by a third party (Severnside Distribution Land Ltd), which are separate to this Application, to relocate the Red Rhine along the northern edge of the Proposed Development Site under the extant 1957/58 planning consent for this part of Severnside. This is described further in Chapter 7: Assessment Methodology. At the time of writing, this work is expected to be completed in early 2015.
3.2.5. A secondary rhine is currently located to the south of the Proposed Development Site, which serves as a main tributary to the Red Rhine. This runs across land known as ‘Crook’s Marsh’ in a south to north direction, and is hereafter referred to as the ‘Crook’s Marsh Stream’.
3.2.6. Shrub vegetation on the Proposed Development Site is limited and mainly concentrated to the entrance/egress to/from Ableton Lane and along the rhines. There are currently no buildings or structures onsite. Some small mature ash trees are located approximately in the centre of the Generating Station Site adjacent to the northeast bank of the Red Rhine. None of the trees onsite has tree preservation orders (TPOs) and they are considered to be in poor condition (see Chapter 16: Ecology).
3.2.7. There are 5 electricity pylons and associated 400 kilovolt (kV), 132kV and 11kV overhead lines (OHLs) located within the CCR Site. The 11kV and 400kV lines cross the Generation Station Site in the southeast corner. The two 132kV lines have recently been decommissioned by Western Power Distribution.
3.2.8. There are redundant railway tracks immediately north of the Generation Station Site and within the northwest corner of the Proposed Development Site. This former railway line branches off the Severn Beach line and heads via a tunnel under the A403 towards Severnside works, although it is no longer functional. There is a fence line currently separating the redundant railway track from the rest of the Proposed Development Site, as shown in Figure 3-2 (Volume III of this PEI Report). This fence line also acts as a barrier between the Proposed Development Site and the adjacent former Terra Nitrogen and ICI site.
3.2.9. A number of dirt tracks cross the Proposed Development Site currently to provide access to the electricity pylons. These are private tracks and run from Ableton Lane, crossing the Red Rhine to the northern boundary and then along the northern boundary of the Proposed Development Site in a southerly direction.
3.2.10. There is an existing Public Right of Way (PROW) located immediately south of the Proposed Development Site in Crook’s Marsh, which terminates at the southern Site boundary, as illustrated in Figure 3-2 (Volume III of this PEI Report). No PROWs currently cross the Proposed Development Site.
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PEI Report – Chapter 3 The Site and Its Surroundings
3.2.11. The following figures present a series of photographs of the Proposed Development Site and nearby surroundings at the time of drafting this PEI Report (pre-01 December 2013). The existing site conditions are shown to be predominantly open grassland with scattered shrub:
• Plate 3-1 [Photo Number 1] - shows the Red Rhine from the Utilities, Services and Landscaping Area, just south of the CCR Site. This is looking in a westerly direction showing Seabank 1 & 2 in the background and the existing OHLs dissecting the CCR Site.
• Plate 3-2 [Photo Number 2] - taken from the Generating Station Site and showing a closer view of Seabank 1 & 2.
• Plate 3-3 [Photo Number 3] - a photograph facing northeast from the Generating Station Site towards the redundant railway tracks and the former Terra Nitrogen and ICI site.
• Plate 3-4 [Photo Number 4] – shows the existing trees onsite, looking in a southeasterly direction facing towards the CCR Site.
• Plate 3-5 [Photo Number 5] – shows the Red Rhine within the CCR Site, facing south towards the nearby Avonmouth LNG Storage Facility, which is discussed further later in this chapter.
• Plate 3-6 [Photo Number 6] - a photograph taken facing north from the centre of the CCR Site. This shows the existing OHLs which cross the CCR Site in a northeast to southwest direction to Seabank Substation.
3.2.12. The location and direction of where the photographs were taken provided are illustrated in Figure 3-2 (Volume III of this PEI Report).
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Plate 3-1: Photograph 1 from the centre of the Proposed Development Site, facing west towards Seabank 1 & 2 [Date taken, 04/07/2013]
Plate 3-2: Photograph 2 from the Centre of the Generating Station Site, facing West towards Seabank 1 & 2 [Date taken, 01/07/2013]
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Plate 3-3: Photograph 3 from the Generating Station Site, facing Northeast towards the redundant railway tracks. [Date taken, 01/07/2013]
Plate 3-4: Photograph 4 from the Generating Station Site, facing Southeast and showing the existing trees [Date taken, 01/07/2013]
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Plate 3-5: Photograph 5 from the CCR Site adjacent to the Red Rhine, facing East [Date taken, 30/08/2012]
Plate 3-6: Photograph 6 from the Centre of the CCR Site, facing North [Date taken, 30/08/2012]
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3.3. Existing Services within the Proposed Development Site
3.3.1. A number of existing buried and above ground services are present on the Proposed Development Site. A description of these is provided below and is illustrated in Figure 3-3 (Volume III of this PEI Report).
Gas Pipelines
3.3.2. There are two natural gas pipelines currently supplying Seabank 1 & 2, which are partly located within the Proposed Development Site: a 42 inch (”) (1,050mm) diameter gas pipeline owned by Seabank Power Limited, which transports gas from Abson to Severnside (known as the ‘Abson pipeline’); and an 18” (450mm) pipeline owned by National Grid Gas (known as ‘Feeder 14’). Both of these pipelines run beneath the Proposed Development Site adjacent to the southern boundary, as shown in Figure 3-3 (Volume III of this PEI Report).
3.3.3. The Feeder 14 pipeline has an off-take supplying the National Transmission System (NTS) within the Seabank 1 & 2 gas receiving station. National Grid currently provides a gas capacity of 19.1 gigawatt hours per day (GWh/day), which is sufficient to meet the base load fuel demand for Seabank 2 of 18.7 GWh/day (the Abson pipeline can feed Seabank 1). The Feeder 14 line runs from the southeast of the Proposed Development Site along the southern boundary (within the Proposed Development Site) to the Seabank 1 & 2 gas receiving station (see Figure 3-3, Volume III of this PEI Report). It rises above ground as soon as it enters the Seabank 1 & 2 site, before terminating at an Above Ground Installation (AGI) owned by National Grid Gas within the Seabank 1 & 2 station.
3.3.4. The Abson pipeline runs from the southeast corner of the Proposed Development Site and crosses to the southwest corner, before coming above ground in the northeast corner of the existing Seabank 1 & 2 station. This pipeline runs through areas designated for development under this application and will need diverting as part of the Proposed Development, as described in Chapter 5: Enabling Works and Construction.
3.3.5. There is also a third gas pipeline owned by Wales & West Utilities that runs through the southeast boundary of the Generation Station Site in a southeast to northwest direction. This pipeline is located within the Utilities, Services and Landscaping Area and therefore should not require diverting.
Water Pipelines
3.3.6. A 24” (600mm) water main owned by Bristol Water is located within the Proposed Development Site and runs along its southern Site boundary. Bristol Water requires an easement strip of 5m either side of the pipeline, however this will not
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directly impact on the Proposed Development as it is located within the Utilities, Services and Landscaping Area.
3.3.7. A private water pipeline runs also north to south across the Generating Station Site to supply the industrial estate to the derelict Terra Nitrogen and ICI site to the north. This redundant private water pipeline crosses the 24” water main and will require decommissioning or diverting as part of the enabling works for the Proposed Development.
3.3.8. Seabank 1 & 2 is connected to Wessex Water’s Bristol Waste Water Treatment Works (WWTW), which is located approximately 3.5km south of the Proposed Development Site, via two existing pipelines: a 500mm supply pipe and a 350mm return, both of which are maintained and operated by Wessex Water Ltd. These pipelines do not currently extend onto the Proposed Development Site and terminate at a receiving station on the western side of the Seabank 1 & 2 station.
Overhead Electrical Lines (OHLs)
3.3.9. There are currently 400kV, 132kV and 11kV OHLs crossing the CCR Site in an east to west direction, and with five pylons on the CCR Site. Figure 3-3 (Volume III of this PEI Report) illustrates the locations of these OHLs. These lines do not need diverting to enable the Proposed Development, with the exception of the 11kV line, which will be diverted underground as described in Chapter 5: Enabling Works and Construction.
3.4. Proposed Development Site History
3.4.1. The Proposed Development Site has generally remained grassland since the first published map in 1886, with the exception being the addition of field boundaries, hedges, the Red Rhine, a railway track, and more recently, electricity pylons.
3.4.2. Post 1955, a series of ‘works’ were built in the area surrounding the DCO Site under the extant 1957/58 consent, including the introduction of the railway tracks running north to east along the northern boundary of the Proposed Development Site. Chapter 7: Assessment Methodology provides further details on the 1957/58 consent.
3.4.3. Since then, the surrounding area has seen increasing development from a number of industrial tenants. The former Terra Nitrogen and ICI site, which has now been demolished, is shown located along the northern site boundary of the Proposed Development Site. The access road from Ableton Lane that once led through the centre of the Proposed Development Site into the former Terra Nitrogen and ICI site has been terminated at the southern boundary of the Proposed Development Site, along with the PROW that runs through the field to the south.
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3.4.4. No further changes are evident in the local area until the Seabank 1 & 2 power station located immediately southwest of the Proposed Development Site was constructed in approximately 2000 on the site of the former Seabank Gas Works.
3.4.5. As part of the construction of Seabank 1 (the first module), a number of gas and water service pipelines were installed beneath the Proposed Development Site, and in 2006 five electricity pylons were built within the south-eastern corner of the Proposed Development Site.
3.4.6. A more detailed description of the Proposed Development Site’s history is presented in Table 3-1.
Table 3-1: Historical Map Descriptions of the Proposed Development Site
Published Date
Map Scale
Description
1881 1:2,500 The Proposed Development Site comprises a series of undeveloped fields with field boundaries. An unnamed track is mapped across the centre of the Proposed Development Site from southwest to northeast. A second unnamed track runs southeast to northwest along the north western boundary, and a series of drainage ditches cross-cross the Proposed Development Site.
1957/58 Consent
1965 1:10,560 The Proposed Development Site remains largely unchanged until pre 1965 when a drain is developed through the centre of the site running southeast to northwest (the diversion of the Red Rhine).
A rail track has been developed in the northern section of the Proposed Development Site and continues toward the southeast, extending into the CCR Site (it is labelled as dismantled by 1999 mapping).
1970 1:1,250 The square feature along the southern boundary is labelled as Stowick Cottage. The three rectangular features are no longer present. The track running through the centre of the site is labelled Ableton Lane. The remainder of the site is largely unchanged.
1971 – 1972 and 1972 – 1977
1:2,500 A rectangular embankment feature is shown on the southern boundary of the Proposed Development Site in the eastern section which may be associated with the development of a drainage ditch. The feature is not shown on mapping after 1992.
1975 1: 10,000 The drain developed through the centre of the Proposed Development Site is now labelled Red Rhine.
A drain appears to have been developed in line with the proposed route of the electrical connection.
1992 1:2,500 Stowick Cottage is no longer present. The remainder of the Proposed Development Site is largely unchanged.
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2006 1: 10,000 Five pylons are now present on the Proposed Development Site. The remainder of the site is largely unchanged.
3.5. Area Surrounding the Proposed Development Site
3.5.1. Directly to the north of the Proposed Development Site is the former Terra Nitrogen and ICI site, which was most recently used as a fertiliser manufacturing plant. It ceased to operate in 2008 and the majority of the buildings associated with the former use of the site have been demolished; it is now predominantly a cleared and level site of hardstanding and crushed rubble.
3.5.2. The former Terra Nitrogen and ICI site is currently subject to proposals for a separate CCGT power station by Scottish Power for the ‘Avon Power Station’, which forms part of the cumulative assessment of this report, in terms of the potential for cumulative effects when considered with this Proposed Development and associated infrastructure (see Chapter 7: Assessment Methodology).
3.5.3. The land to the east and northeast of the Proposed Development Site was until recently undeveloped fields. This area is being developed by Severnside Distribution Land Ltd for offices and warehousing (referred to as Central Park in Chapter 7: Assessment Methodology) and is currently being raised to provide flood protection.
3.5.4. A roundabout has recently been constructed immediately to the east of the Proposed Development Site, as part of a new distributor road through Central Park. Severnside Distribution Land Ltd is proposing to link this new roundabout to the A403, by creating a new Spine Access Road which will run along the northern perimeter of the Proposed Development Site (as illustrated in Figure 4-3, Figure 4-4, and Figure 4-9, Volume III of this PEI Report). The Spine Access Road is one of the cumulative developments assessed within this PEI Report, as described in Chapter 7: Assessment Methodology.
3.5.5. Beyond Central Park, approximately 1km east of the Proposed Development Site is the M49 motorway. The Avonmouth LNG Storage Facility and Hallen Industrial Estate are situated to the southeast of the Proposed Development Site, and an area of undeveloped grassland known as Crook’s Marsh is situated immediately south of the Proposed Development Site (west of the Avonmouth LNG Storage Facility).
3.5.6. The existing Seabank 1 & 2 generating station is located immediately southwest of the Proposed Development Site, with the site of the consented SITA waste recycling facility (Local Planning Authority reference PT12/1303/MW, currently under construction) to the northwest of the Proposed Development Site. The
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Severn Estuary is approximately 400m west of the nearest point of the Proposed Development Site.
3.5.7. Seabank Substation is located within the Seabank 1 & 2 compound, approximately 350m south of the Proposed Development Site.
3.6. Other DCO Land
3.6.1. The DCO Application will also include Associated Development for works related to the installation of the proposed cooling water pipeline, the electrical connection to Seabank Substation, and towns and foul water connections, which lie outside of the Proposed Development Site. These works will take place in an area defined as Other DCO Land.
3.6.2. The Other DCO Land is located entirely within the administrative boundary of BCC. The approximate National Grid Reference of the most northerly and southerly parts of the Other DCO Land are 35356, 18281 and 35315, 17947, respectively.
3.6.3. The Other DCO Land covers an area of approximately 19ha and connects the Proposed Development to the electrical and water connection points within the Seabank 1 & 2 generating station site and also covers a proposed cooling water pipeline corridor to the Bristol WWTW.
3.6.4. The part of the Other DCO Land for the electrical connection runs from the northwest corner of the Proposed Development Site southwards within the Seabank 1 & 2 site to the Seabank 400kV Gas Insulated Substation (GIS), and is approximately 440m in length and 100m wide. An additional utilities corridor has been included within the DCO Site to incorporate foul water and mains water connections to the Site and includes the northernmost 100m within the Seabank 1 & 2 station, between Severn Road and the Proposed Development Site (as illustrated in Figure 3-1, Volume III of this PEI Report). These parts of the DCO Site are hardstanding and concrete.
3.6.5. The Other DCO Land for the proposed cooling water pipeline corridor runs from the western most point of the Proposed Development Site, around the perimeter of Seabank 1 & 2, in a southward direction to the Bristol WWTW and is approximately 4.5km in length and generally 30m wide.
3.6.6. Due to the length of the proposed cooling water pipeline corridor, the Other DCO Land has been split into three figures: Figures 3-4a, 3-4b, and 3-4c (Volume III of this PEI Report) provide an aerial image of the Other DCO Land. They also show other notable features in the vicinity, including the photograph locations for the photographs presented in Plates 3-7 to 3-15.
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Plate 3-7: Photograph 7 showing the connection between the Proposed Development Site and Seabank 1 & 2 [Date Taken 20 February 2013]
Plate 3-8: Photograph 8 showing the entrance of Seabank 1 & 2 Site [Date Taken 20 February 2013]
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Plate 3-9: Photograph 9 of Seabank 400kV Substation [Date Taken 20 February 2013]
Plate 3-10: Photograph 10 showing corner of Chittening Road and Severn Road [Date Taken 11 November 2013]
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Plate 3-11: Photograph 11 showing the corner of Smoke Lane and Chittening Road [Date Taken 04 September 2013]
Plate 3-12: Photograph 12 showing footpath facing west running adjacent to the railway [Date Taken 04 September 2013]
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Plate 3-13: Photograph 13 showing culvert facing south [Date Taken 04 September 2013]
Plate 3-14: Photograph 14 – Facing north across Popular Way East [Date Taken 04 September 2013]
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Plate 3-15: Photograph 15 – Facing north from the Bristol WWTW Entrance [Date Taken 04 September 2013]
3.6.7. The proposed cooling water pipeline corridor extends from the most westerly point of the Proposed Development Site, around the perimeter (but within) the Seabank 1 & 2 site and then south towards the Seabank Substation (Photograph 8), before turning south to Chittening Road.
3.6.8. The proposed cooling water pipeline corridor follows the route of an internal access road within Seabank 1 & 2, after which it follows a footpath past the Seabank Substation towards Chittening Road.
3.6.9. The proposed cooling water pipeline corridor runs south alongside Chittening Road and includes the grass verges, with the Viridor Resource Recovery Centre and Sevalco W4B sites to the east (Photograph 9). This part of the Other DCO Land is situated on the west side of Chittening Road for the first 100m, before crossing it to the opposite side of the road and continuing south to Chittening Industrial Estate (Photograph 10 & 11). It therefore includes the grass verges either side of Chittening Road, and crosses this road in one location.
3.6.10. Figure 3-4b (Volume III) illustrates the part of the proposed cooling water pipeline corridor in the vicinity of the operational railway line. The proposed cooling water
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pipeline corridor continues south, passing the firefighting training station and includes an existing tarmacked footpath and grass field up to the railway.
3.6.11. The proposed cooling water pipeline corridor crosses under the railway line at grid reference 353087,180906 and turns in a easterly direction adjacent to the railway on grassland for approximately 200m towards an existing distribution centre operated by Honda, as shown on Figure 3-4b (Volume III of this PEI Report). This part of the proposed cooling water pipeline corridor is partly tarmacked and follows the route of an existing footpath that runs adjacent to the railway, with grass verge alongside (Photograph 12).
3.6.12. Figure 3-4c (Volume III) shows the part of the proposed cooling water pipeline corridor between the footpath adjacent to the southern side of the railway and the WWTW. It predominantly follows the existing PROW, which are hard surfaced, or on grass verges alongside the PROW.
3.6.13. Photograph 13 illustrates a culvert, facing south with the existing 300mm and 550mm water pipelines exposed, which the proposed cooling water pipeline corridor crosses.
3.6.14. It then crosses Lawrence Weston Road (Photograph 14), and reaches the Bristol WWTW via a grassed verge, as shown in Photograph 15.
3.6.15. A detailed description of the land use and habitats of the Other DCO Land is presented in Chapter 16: Ecology.
3.6.16. A description of the site history of the Other DCO Land and the surrounding area is presented in Chapter 13: Ground Conditions.
3.7. Sensitive Receptors in the Vicinity of the Proposed Development Site and Other DCO Land
3.7.1. When undertaking an EIA it is important to understand which receptors will be considered as part of the assessment. Key receptors for each topic area have been identified as part of the assessment process and details are included in the relevant chapters. Where distances are quoted here and in following chapters the distance is defined (unless otherwise stated) as the closest point from the site boundary to the location being described).
3.7.2. The area surrounding the Proposed Development to the south and north is occupied by various industrial uses, both large and small, whilst the land to the east and northeast of the Proposed Development Site currently remains undeveloped open fields, although this area is subject to a separate development by Severnside Distribution Land Ltd.
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Nearest Residential Properties
3.7.3. The nearest residential properties to the Proposed Development Site are located approximately 1.5km north of the Proposed Development Site in Severn Beach, and a number of small number of farms located approximately 1.1km southeast.
3.7.4. Other small residential settlements in the vicinity of the Proposed Development Site including Pilning, Hallen, and Easter Compton, approximately 1.5km north, 2km south east, and 2.2km northeast respectively.
3.7.5. The larger communities of Avonmouth and Bristol are located some 5km southwest and 10km east of the Proposed Development Site respectively.
3.7.6. The nearest residential properties to the Other DCO Land are situated approximately 800m east of the proposed cooling water pipeline corridor at its most southern point (near the WWTW). There are no residential properties closer than 800m between the WWTW and Seabank 1 & 2, as shown in Figure 3-5 (Volume III of this PEI Report).
Nature Conservation
3.7.7. A number of conservation designations exist within 2km of the Proposed Development Site of both European and national significance, in particular the Severn Estuary.
3.7.8. The Severn Estuary is located approximately 400m to the west of the Proposed Development Site and is an internationally designated Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar Site and Site of Special Scientific Interest (SSSI) due to both habitat and species assemblages.
3.7.9. The SAC designation is a response to the rich marine and terrestrial habitat and species found within the Severn Estuary and includes the following features:
• Estuaries;
• Tidal rivers;
• Mud flats;
• Sand flats;
• Lagoons (including saltwork basins);
• Salt marshes;
• Salt pastures;
• Salt steppes;
• Reefs;
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• Migratory fish (river and sea lamprey and twaite shad) [see Figure 3-5, Volume III of this PEI Report]; and
• Species of bird/waterfowl/fish.
3.7.10. Further details of the above features are described in Chapter 16: Ecology. It should be noted however that not all of the features for which the Severn Estuary SAC is designated are to be found within close proximity to the Proposed Development Site itself.
Biodiversity Action Plan (BAP) Habitat
3.7.11. The majority of the Proposed Development Site comprises marshy grassland and there are a limited number of areas of scrub and hedgerow, which are designated as a ‘broad habitat’ under the UK Biodiversity Action Plan (UK BAP). The Proposed Development Site is also immediately adjacent to an area designated as Coastal and Floodplain Grazing Marsh, which is a BAP priority habitat, identified as “being the most threatened and requiring conservation action”.
3.7.12. Interconnecting rhines (drainage ditches) on the Proposed Development Site and immediately adjacent have been identified by the Local Wildlife Trust as Sites of Nature Conservation Interest (SNCI). The Red Rhine is the largest drainage channel within the area and running through the Proposed Development Site in an east to west direction.
3.7.13. It should be noted that the proposed water cooling pipeline corridor crosses local rhines, which are designated as SNCI.
Flood Risk
3.7.14. The River Severn is the closest principal watercourse and is located approximately 400m west of the Proposed Development Site. The Proposed Development Site lies entirely within Flood Zone 3a as classified by the EA, and is therefore at risk from coastal flooding in a 1 in 200 year event or from fluvial flooding during a 1 in 100 year event.
Historic Environment
3.7.15. The wider landscape encompassing the DCO Site consists of a combination of open rural landscape, heavy industry, villages, towns and the estuary. The landscape around the DCO Site has been strongly influenced by its past and present industrial land uses.
3.7.16. Three scheduled monuments have been identified within 5km of the Proposed Development Site, and are noted in Chapter 15: Archaeology and Cultural Heritage.
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3.7.17. Fifteen Grade II and fourteen Grade I listed buildings exist within 5km of the Proposed Development Site, whilst thirteen of the Grade II listed buildings are located within 2km. Underground archaeology may be present onsite or in the vicinity of the Proposed Development Site, which is discussed in Chapter 15: Archaeology and Cultural Heritage.
Other Receptors
3.7.18. Other potential sensitive receptors have been identified within 2km of the Proposed Development Site based on a review of available maps, aerial photographs, initial studies, site visits and consultations:
• Fourteen non statutory designated sites for nature conservation within 1km of the Proposed Development Site. All of which are designated as SNCI and two which area also designated as Avon Wildlife Trust Sites (AWTS);
• Ecological receptors (bats and breeding birds);
• Traffic and transport receptors;
• Local PROW (as located in Figure 3-5, Volume III of this PEI Report); and
• Key short, medium and long-distance views into the Proposed Development Site.
3.7.19. Figure 3-5 (Volume III) illustrates the main constraints and environmental receptors within the surrounding area.
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4. Project Description
4.1. Introduction
4.1.1. This chapter of the PEI Report describes the Proposed Development and its associated infrastructure, and is used in subsequent technical chapters to assess the potential effect on the environment and socio-economic conditions.
4.1.2. Chapter 5: Enabling Works and Construction presents a description of the key activities and processes that will be carried out during the enabling works and construction of the Proposed Development.
4.2. Overview
4.2.1. The Applicant is seeking a DCO for the development of a generating station fuelled on natural gas generating up to 1,400MWe net electrical capacity. The generating station will comprise up to two CCGT units with a total capacity of up to 1,400MWe, and gas-fired peaking plant totalling up to 240MWe net electrical capacity. The electrical capacity of the CCGTs will be reduced if the peaking plant is built to ensure the total output capacity of the Proposed Development does not exceed 1,400MW.
4.2.2. This combination of CCGT units and peaking plant is required to be able to effectively respond to national need to meet electricity demand, as discussed in Chapter 6: Project Need and Alternatives of this PEI Report. CCGTs are recognised to be a highly efficient way to generate electricity, while peaking plant can be operated for short durations and started at short notice to rapidly meet fluctuating electrical demand.
4.2.3. The CCGT units consist of a gas turbine, a Heat Recovery Steam Generator (HRSG), a steam turbine, and an electrical generator. Electricity is generated both by the gas turbine and the steam turbine, with the exhaust gases from the gas turbine generating steam through the HRSG to power the steam turbine.
4.2.4. The capacity of the CCGT units will be determined by the specific technology selected through a procurement exercise at the time of construction of the Proposed Development. The inclusion and capacity of the peaking plant is therefore optional and dependent on the output capacity of the CCGT units, as the net electrical capacity of the Proposed Development will not exceed 1,400MWe.
4.2.5. Supporting infrastructure such as cooling water system, water treatment plant and other services are required on the Proposed Development Site, and these are described in more detail later in this chapter.
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4.2.6. The Proposed Development also requires the installation of a new water pipeline to supply water for the cooling water system from Bristol WWTW, towns and foul water connections, and an electrical connection to Seabank Substation. These are considered to be Associated Development and are described further below.
4.2.7. In accordance with the requirements of the National Policy Statement for Fossil Fuel Electricity Generating Infrastructure (NPS EN-2) (Ref. 4-1), the plant is being designed to be both Carbon Capture Ready and Combined Heat and Power (CHP) Ready.
4.2.8. There are some aspects of the Proposed Development design that have yet to be fixed. It will not be possible to fix these elements in advance of a contract being awarded for the detailed design and construction of the Proposed Development. For example, the precise location and scale of the buildings within the Proposed Development may vary depending upon the contractor appointed and their specific selection and configuration of the plant and process equipment. The design of the Proposed Development therefore needs to incorporate a degree of flexibility to allow for such circumstances.
4.2.9. The elements of the Proposed Development where flexibility is required are described in detail below. In order to ensure a robust assessment of the likely significant environmental effects of the Proposed Development, the EIA will be undertaken adopting the principles of the ‘Rochdale Envelope’, as advocated in the Planning Inspectorate’s Advice Note 9 (Ref. 4-2). This will involve assessing the maximum and minimum parameters for the elements where flexibility needs to be retained. Where this approach is applied to the specific aspects of the EIA this has been confirmed within the relevant chapters of this PEI Report and will also be confirmed within the ES, which will report on the complete findings of the EIA and form part of the Application for Development Consent.
4.2.10. Further detail is provided in the following sections.
4.3. Description of the Proposed Development
4.3.1. The NSIP, referred to as the Proposed Development in this PEI Report, has been broken down into land parcels as shown in Figure 4-1a (Volume III of this PEI Report). Figure 4.1b shows the proposed cooling water pipeline corridor that will be constructed as Associated Development to the Proposed Development.
4.3.2. The Proposed Development comprises the following main components:
• Up to two CCGT units, comprising up to two gas turbines, up to two steam turbines, and up to three electricity generators within turbine building(s);
• Up to two HRSG within heat recovery steam generator building(s);
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• Up to two emissions stacks associated with the CCGT units and associated emissions monitoring systems;
• Cooling for the Proposed Development is to be provided by a hybrid cooling water system, supplied with water from Bristol WWTW. The water will be delivered to the Proposed Development Site through a new underground water pipeline which will supply Seabank 1 & 2 as well as the Proposed Development;
• A grid connection to the UK transmission network via an existing sub-station;
• A peaking plant facility fuelled by natural gas and with black start capability on distillate fuel oil, with a net electrical output capacity of up to 240MWe.
4.3.3. In addition, the main plant is supported by additional infrastructure including up to three generator transformers, a water treatment plant, pumps and storage tanks, gas reception facility, and administration and control buildings.
4.3.4. As required by the EU Directive on Geological Storage of Carbon Dioxide (Ref. 4-3) and DECC Guidance on Carbon Capture Readiness (Ref. 4-4), an area has been allocated for potential future use for the retrofitting of carbon capture and compression equipment, should it be required to be installed in the future. This area will be used for temporary contractor’s laydown and facilities during the construction of the Proposed Development.
The Proposed Development
4.3.5. The Proposed Development has been designed to operate independently of the existing Seabank 1 & 2 generating station, however there will be a number of shared services including access roads, cooling water treatment and supply, gas supply and grid connection, and foul water and towns water connections.
4.3.6. The CCGTs will be natural gas fired, with the fuel sourced from the National Grid Gas Transmission Network. The existing Seabank 1 & 2 station is currently supplied by two high pressure natural gas feeds (the Abson pipeline and Feeder 14) that enter the southeast corner of the Proposed Development Site (the Site) and extend through the Proposed Development Site to Seabank 1 & 2. The Abson pipeline will need to be diverted within the Site boundary (parallel to the Feeder 14 pipeline which runs along the southern boundary of the Site) and will be used to supply the gas the Proposed Development via an off-take within the Site. This is discussed in Chapter 5: Enabling Works and Construction.
4.3.7. The use of natural gas means that emissions of sulphur dioxide (SO2) and particulates from the Proposed Development will be negligible. Emissions of
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nitrogen oxides (NOx) will be controlled by primary means and the use of dry low NOx burners operated and controlled through an automated process control system in accordance with Best Available Techniques (BAT). In this way, emissions will be controlled to meet the requirements of the Industrial Emissions Directive (IED) (Ref. 4-5); secondary abatement of emissions to air is not proposed or considered necessary.
4.3.8. The CCGTs and peaking plant will be located in the western half of the Proposed Development Site, within an area defined as the Generating Station Site, which is adjacent to the existing Seabank 1 & 2, as shown in Figure 3-1, Volume III of this PEI Report. This corresponds with development parcels 1, 2 and 3 in Figure 4-1a (Volume III). The eastern area is the area to be retained so that the Proposed Development is Carbon Capture Ready (CCR).
4.3.9. The main structures that form the Proposed Development will comprise:
• One or two turbine buildings with a maximum height of up to 33m above the maximum finished ground level (up to 41.5m AOD following land raising of the ground to a maximum 8.5m AOD, as discussed in Chapter 5: Enabling Works and Construction), along with up to two 90m high exhaust stacks (up to 98.5m AOD);
• One or two HRSG buildings with a maximum height of up to 45m (up to 53.5m AOD);
• Up to two banks of 24 hybrid cooling water systems, each with a maximum diameter of 17.5m and a height of up to 19m (up to 27.5m AOD); and
• The peaking plant, which will have a maximum height of up to 24m (32.5m AOD), along with two exhaust stack 45m in height (up to 53.5m AOD).
4.3.10. There will also be additional ancillary structures onsite of lower height and a smaller footprint than these main buildings to accommodate for example, workshops and offices, which are illustrated in Figures 4-2 to 4-6 (Volume III of the PEI Report) and listed in Tables 4-1 and 4-2.
4.3.11. As the final technology selection has not been made, there are two potential plant configurations that could be utilised for the Proposed Development: single-shaft and multi-shaft. Although they result in the same electrical output, they do result in a slightly different mode of operation and appearance. It is proposed that the ‘Rochdale Envelope’ approach is used to retain the flexibility to build either plant configuration, as discussed in Chapter 2: The DCO and EIA Process. Both configurations have therefore been assessed in this PEI Report and will be
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retained in the assessments presented in the final ES to be submitted with the DCO Application. Whichever configuration gives rise to that worst-case predicted effect has been assessed in the individual technical chapters.
4.3.12. As outlined in the previous paragraph, the key environmental difference between the two configurations is their visual appearance, as a number of buildings are combined for the multi-shaft arrangement and there are differing numbers of generators and transformers, resulting in a slightly smaller footprint for the multi-shat configuration. This is discussed further later in this section.
4.3.13. The Proposed Development will have a design life of 30 years, which may be extended depending on the number of running hours and condition of the plant. The technical assessments have been based on this design life.
4.3.14. The plant will have the ability to operate twenty-four hours per day, seven days per week, if required, although with periodic offline periods for maintenance.
4.3.15. The actual hours of operation of the CCGTs or the peaking plant will be subject to the national demand for electricity and the economic viability of gas-fired generation. It is anticipated that the CCGTs will operate at an average 31% load factor (an average 2,716 hours per year) over the course of its lifetime, with the peaking plant expected to run for short periods of time during high demand. For the purposes of the assessments undertaken in this PEI Report however, it has been conservatively assumed that the CCGTs could operate for up 7,884 hours a hour (90% availability) and the peaking plant up to a maximum 1,500 hours a year (approximately 17% availability).
4.3.16. As discussed above, an area has been reserved for the potential future siting of carbon capture and compression equipment, should it be required at a future date, in order to meet the requirements set out in the EU CCS Directive for Geological Storage of Carbon Dioxide and to demonstrate that the Proposed Development is CCR. The actual design and consenting of CCS technology and infrastructure does not form part of this DCO Application, as it is not currently required to be installed at the Site. Any CCS infrastructure would need to be consented separately at the time it is required in the future. However, in accordance with DECC CCR Guidance requirements, the CCR Site is included within the Proposed Development Site boundary. It is also proposed that this area is utilised for construction and laydown activities, as discussed in Chapter 5: Enabling Works and Construction.
4.3.17. Opportunities for the provision of low-grade steam or waste heat to local third parties are being explored. If feasible this will enable the plant to operate as a CHP plant, which would maximise the use of available heat from the fuel and increase the overall plant thermal efficiency. The feasibility of CHP has been further explored in the CHP-Ready report that has been prepared to accompany
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the DCO Application. This is presented in Appendix N, Volume II of this PEI Report.
Finished Ground Levels
4.3.18. It is expected that the Generating Station Site will need to be raised from current levels in order to manage potential flood risk, as discussed in Chapter 14: Flood Risk, Hydrology and Water Resources.
4.3.19. Hydraulic modelling undertaken to inform the Flood Risk Assessment indicates that the finished floor levels within the Generating Station Site will need to be raised to a minimum of 8.31m AOD to protect from extreme tidal flooding events. The DCO Application therefore includes for the ability raise this part of the Proposed Development Site by up to an average 2.2m to 8.5m AOD, as illustrated in Figure 5-1, Volume III of this PEI Report.
4.3.20. This represents a maximum ground level and incorporates more than the suggested degree of contingency by the Environment Agency. This is to avoid committing to an overly precise figure that a Contractor may be unable to deliver. It is expected that the finished site levels will be less than this to allow the construction Contractor to lay a gravel or concrete platform for construction. Certain infrastructures such as the cooling water system, which are inherently bunded and therefore protected from flooding, could also be constructed at current site levels or lower than this maximum ground height.
4.3.21. Land raising will not be undertaken on the CCR Site or the Utilities, Services and Landscaping Area within the Proposed Development Site. The ‘Other DCO Land’, within which the electrical connection and water pipeline is being constructed (and which lies within BCC’s administrative boundary), will also be retained at current site levels.
4.3.22. It is estimated that up to 158,000m3 of material may be required for land raising, based on the predicted maximum extent of land raising defined above. For the purpose of assessing the effect of road traffic movements, it has been assumed that this material will be imported to Site by HGV over the course of 6 months. The effect of these HGV movements on the road network is discussed in Chapter 10: Traffic and Transport.
Layout Configurations
4.3.23. As discussed above, at this stage in the development of the plant design, it is not possible to define which plant configuration will be required and therefore both options are retained within the DCO Application and assessed within the EIA process.
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4.3.24. A single-shaft configuration consists of only one gas turbine, steam turbine, generator and HRSG per CCGT unit, with the gas turbine and steam turbine coupled to the generator.
4.3.25. The multi-shaft configuration also includes two gas turbines and generators (the same number as two single-shaft units), but supplies steam from the HRSG to a separate steam turbine and generator that is common to each train.
4.3.26. Plate 4-1 presents a schematic diagram to illustrate the differences between these arrangements. The single-shaft arrangement illustrated in Plate 4-1 only includes one CCGT unit. The Proposed Development may therefore contain twice the arrangement shown below should two single-shaft arrangements be built.
Plate 4-1: Single and Multi-shaft Arrangements
* The single-shaft arrangement illustrates one unit only. The Proposed Development will have up to two single-shaft.
4.3.27. Figures 4-2 and Figure 4-3 (Volume III of this PEI Report) illustrate the indicative layouts (based on maximum parameters) for the single-shaft and multi-shaft configurations. The building footprint for the multi-shaft configuration is shown to be slightly less than the single-shaft configuration, and the massing of the turbine and HRSG buildings orientated slightly differently, as described below. Regardless of which design is selected it would be within the development parcels illustrated in Figure 4-1a (Volume III of this PEI Report).
Height and Massing
4.3.28. In accordance with the principles of the Rochdale Envelope, as set out in the Planning Inspectorate Guidance Note 9, the DCO Application defines the maximum and minimum parameters for the Proposed Structures such that the envelope can be defined and adequately assessed.
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4.3.29. In brief, the maximum parameters comprise two CCGT units, two banks of cooling water systems (containing a total 24 cooling water system), and a peaking plant facility plus Associated Development.
4.3.30. The indicative layouts and illustrations show the maximum and minimum footprints and heights of the buildings and structures, as well as the general massing of the Proposed Development. Figure 4-1a (Volume III of this PEI Report) illustrates that there is some flexibility on where individual buildings can be located within a development parcel.
4.3.31. The technical assessments have taken into account the Rochdale Envelope and, where applicable, assessed the worst case parameters for each parameter. To facilitate the stack height determination and undertake the air quality impact assessment however it was necessary to model the stacks and buildings in a specific location, as shown in the layout drawings below. Chapter 11: Air Quality includes a discussion on sensitivity analysis, since small changes in the stack location may be expected at the detailed design stage, however without changing the general massing of the Proposed Development or position of the stacks in relation to the main buildings onsite.
Maximum Parameters
4.3.32. Figures 4-2 and 4-3 (Volume III of this PEI Report) provide an indicative 2-dimensional layout of the Proposed Development based on the maximum building footprints, for the single-shaft and multi-shaft configurations, respectively.
4.3.33. Figures 4-4 and 4-5 (Volume III) illustrates selected cross-sectional drawings showing the maximum building and structure heights for the two configurations.
4.3.34. Irrespective of plant configuration, the tallest structures onsite will be the stacks associated with the CCGT units, which will be 90m high (up to 98.5m AOD, assuming that the finished ground levels are raised to a maximum height of 8.5m AOD as discussed above). The peaking plant stacks will be 45m (up to 53.5m AOD).
4.3.35. The tallest buildings will be the HRSG buildings, which are up to 45m above the finished ground level (up to 53.5m AOD).
4.3.36. The turbine buildings are proposed to be located immediately northwest of the HRSG buildings and will be up to 33m (up to 41.5m AOD) for a single-shaft configuration and up to 35m (up to 43.5m AOD) for a multi-shaft configuration. Further to the northwest, the cooling water systems will be slightly lower, up to 19m in height (up to 27.5m AOD).
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4.3.37. West of the HRSG and turbine buildings, near the southern boundary of the Proposed Development Site, the cooling water backup tank and towns water tank will be up to 28m in height (up to 36.5m AOD).
4.3.38. The structures east of the HRSG buildings are generally lower rise, with the ancillary buildings between 2m and 17m (10.5m AOD to 25.5m AOD). The peaking plant building though is up to 24m (up to 32.5m AOD).
4.3.39. The main massing of the Proposed Development is therefore situated in the centre of the Generating Station Site, with the HRSG buildings and stacks being the most prominent features, along with the peaking plant stacks to the east.
4.3.40. The maximum parameters also include structures to penetrate the ground level to the water table. This is expected to include foundations for the turbine building, HRSG buildings, and cooling water pits.
4.3.41. Figure 4-6 (Volume III of this PEI Report) provide indicative 3D illustrations of the Proposed Development from selected viewpoints, based on the maximum building footprints and heights.
Minimum Parameters
4.3.42. The ‘Rochdale Envelope’ allows a range of parameters to be applied for. A minimum height and footprint for the proposed structures and buildings is therefore discussed in this subsection. The Applicant is not committed to building all the structures and buildings listed in the DCO Application however and has the flexibility to phase the Proposed Development or decide to omit certain features. For example, minimum parameters are provided for the peaking plant, although these are effectively an option, depending on the final choice of CCGT plant, and therefore might never be built.
4.3.43. The stack associated with the CCGT and peaking plant will be 90m high and 45m high respectively (up to 98.5m AOD and 53.5m AOD); no range of parameters is being sought for the stacks to provide certainty of their height and the maximum air quality effects associated with these emission sources.
4.3.44. For the other structures onsite, a height AOD has not been stated since the ground level may not need to be raised to the full 8.5m AOD to satisfy the EA requirements for flood protection.
4.3.45. The HRSG building will be a minimum of 35m above the finished ground level and a minimum footprint of 37m by 25m.
4.3.46. The turbine building is located immediately adjacent to the HRSG building and will be a minimum of 27m above the finished ground level. The turbine auxillary
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building will be a minimum 14m high. These buildings have the greatest physical footprint onsite and are both a minimum of 60m by 33m.
4.3.47. Further to the northwest, the cooling water system will be slightly lower, a minimum of 15m above the finished ground level.
4.3.48. West of the HRSG and turbine buildings, near the southern boundary of the Proposed Development Site on the indicative layout plans, the cooling water backup tank and towns water tank will be a minimum of 16m above the finished ground level.
4.3.49. The structures east of the HRSG buildings are generally low rise, with the ancillary buildings a minimum of approximately 16m above the finished ground level. The peaking plant facility will have a minimum height of 14m.
4.3.50. The main massing of the Proposed Development is therefore situated in the west of the Generating Station Site, with the HRSG buildings and stacks being the most prominent features.
4.3.51. Table 4-1 and 4-2 provide a list of the main structures associated with the Proposed Development and their maximum and minimum parameters for both the single-shaft and multi-shaft configurations, respectively.
Table 4-1: Proposed Development Parameters for the Single-shaft Configuration
Structure Number of units
Maximum Minimum
Height (m)
Length (m)
Width (m)
Height (m)
Length (m)
Width (m)
Turbine Building 2 33 70 37 27 60 33
Turbine Auxiliary Building 2 17 70 37 14 60 33
HRSG Building 2 45 45 30 35 37 25
CCGT Stack 2 90 d8.5 90 d8.5
Peaking Plant building 1 24 77 58 14 59 24
Peaking Plant Stack 2 45 d7 45 d4
Gatehouse 1 4 17 11 3 10 5
Gas Receiving Station 1 2 108 20 2 108 20
Gas Conditioning Compound 1 4 53 18 4 40 14
Hybrid Cooling System 2 19 100 35 15 80 30
Fire Water Tank 1 15 d12 7 d6
Fire Fighting Building 1 5 8 8 4 6 6
Water Treatment Building 1 10 33 14 5 22 8
Demin Water Storage Tank 1 9 d9 6.5 d5
BFW Pump house 2 17 25 24 15 20 18
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Structure Number of units
Maximum Minimum
Height (m)
Length (m)
Width (m)
Height (m)
Length (m)
Width (m)
Chemical Sampling Dosing 2 16.5 25 24 14 20 18
HRSG Auxiliary Building 2 17 25 24 15 20 18
Emergency Diesel Generators 2 3 11 8 3 5 4
Workshop Stores 1 15 36 26 6 26 19
Plant Laydown 1 N/A 34 12 N/A 34 12
Admin Control Building 1 15 48 19 8 24 15
Car Park 1 N/A 50 5 N/A 50 5
GIS and Control Room 1 15 38 14 15 22 14
Distillate Oil Tank 2 12.5 d10 10 d8
Cooling Water Dosing Building 1 4.5 20 10 4.5 15 10
Cooling Water and Towns Water Back Up Tank 2 28 d25 16 d14
Cooling Water Switchgear Building 1 5.6 31 12 3.5 25 8
Transformer compound 2 12 35 24 10 25 20 d=diameter
Table 4-2: Proposed Development Parameters for the Multi-shaft Configuration
Structure Number of units
Maximum Minimum
Height (m)
Length (m)
Width (m)
Height (m)
Length (m)
Width (m)
Turbine Building 1 35 132 60 28 120 58
HRSG Building 2 45 45 30 35 37 25
CCGT Stack 2 90 d8.5 90 d8.5
Peaking Plant building 1 24 77 58 14 59 24
Peaking Plant Stack 2 45 d7 45 d7
Gatehouse 1 4 17 11 3 10 5
Gas Receiving Station 1 2 108 20 2 108 20
Gas Conditioning Compound 1 4 53 18 2 40 14
Hybrid Cooling System 24 19 100 35 15 80 30
Fire Water Tank 1 15 d12 7 d6
Fire Fighting Building 1 5 8 8 4 6 6
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Structure Number of units
Maximum Minimum
Height (m)
Length (m)
Width (m)
Height (m)
Length (m)
Width (m)
Water Treatment Building 1 10 33 14 5 22 8
Water Storage Tank 1 9 d9 6.5 d5
Pump house 2 17 25 24 15 20 18
Chemical Sampling Dosing 1 16.5 25 24 14 20 18
HRSG Auxiliary Building 2 17 25 24 15 20 18
Emergency Diesel Generators 1 3 11 8 3 5 4
Workshop Stores 1 15 36 26 6 26 19
Plant Laydown 1 N/A 34 12 N/A 34 12
Admin Control Building 1 15 49 19 8 24 15
Car Park 1 N/A 50 5 N/A 50 5
GIS and Control Room 1 15 38 14 15 22 14
Distillate Oil Tank 2 12.5 d10 10 d8
Cooling Water Dosing Building 1 4.5 20 10 4.5 15 10
Cooling Water Back Up Tank 2 28 d25 16 d14
Cooling Water Switchgear Building 1 5.6 31 12 3.5 25 8
Transformer compound 3 12 35 24 10 25 20
d=diameter
The Main CCGT Generating Station (Development Parcel 1)
4.3.52. The CCGT operates by combusting natural gas to produce hot gases, which in turn drive a gas turbine. In the gas turbine, gas will be mixed and combusted with compressed air and the hot combustion gases will expand, rotating the turbine blades at high speed. This will drive the generators to produce electricity for export to the national transmission system.
4.3.53. A substantial amount of heat remains in the gas turbine exhaust, which is passed into a HRSG (a type of boiler) to use the heat to produce steam. This in turn is used to drive a steam turbine either connected to the same generator or a separate steam turbine generating module, thereby maximising electricity generation from the fuel being combusted. The exhaust steam from the steam
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turbine is condensed back into water which is returned to the HRSG to continue the process. The waste gases from the HRSG boiler will be released into the atmosphere via an exhaust stack, which will be 90m high (up to 98.5m AOD).
4.3.54. The main difference between open cycle and combined cycle gas turbines (OCGTs and CCGTs respectively) is that CCGT plants use residual heat from the gas turbine exhaust stack to generate steam used in the energy conversion process.
4.3.55. The electrical efficiency of a modern CCGT power station such as this Proposed Development is in the range of about 55-60%, which is considerably higher than that for an OCGT or a conventional coal, oil or gas fired steam turbine generating plant. The Proposed Development is expected to achieve 58% efficiency.
Supplementary Firing
4.3.56. Supplementary firing is a method of producing additional steam to generate additional electricity for short periods by firing a dedicated gas burner located between the gas turbine and the HRSG. Supplementary firing would increase the power output of the CCGT plant by around 0.4%. It does however reduce the efficiency slightly.
4.3.57. At this stage, it is not known if supplementary firing would be designed into the plant, although it is fitted as standard on some CCGT units. It has therefore been included within the Rochdale Envelope assessed for the Proposed Development. It leads to only a marginal increase in the footprint of the HRSG and turbine buildings (of the order of 5m additional length), which has therefore been included in the maximum parameters listed in Table 4-1. It has also been considered prudent to base the assessments on the slightly lower plant efficiency that would result from the inclusion of supplementary firing.
Fuel Type and Source
4.3.58. The fuel source for the turbines will be natural gas, supplied from the UK National Grid Transmission network and in accordance with the gas specification of that network.
4.3.59. The current Seabank 1 & 2 generating station is supplied from two high pressure natural gas feeds from the southeast corner of the Proposed Development. These existing supply pipelines will be used to supply the gas to the Proposed Development Site, though will need to be slightly diverted within Proposed Development Site to accommodate the new plant and a connection taken from it, as discussed in Chapter 5: Enabling Works and Construction.
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Gas Receiving Station
4.3.60. A gas receiving station is required to receive the natural gas fuel from an off take from the Abson pipeline (see Chapter 3: The Site and Its Surroundings), and to depressurise it in advance of using it as fuel in the Proposed development. A pigging facility would be included, which allows a ‘Pipeline Inspection Gauge’ (PIG) to be passed along the pipeline for periodic cleaning and maintenance checks.
4.3.61. The gas receiving station is indicated as being east of the peaking plant facility on the indicative layouts; however it could be located anywhere within the area labelled as Development Parcel 1 or 3 in Figure 4-1a. It would have a maximum height of 2m (10.5m AOD) and a footprint of up to 108m by 20m.
Gas Conditioning Compound
4.3.62. A gas conditioning compound is required to heat, hydrate/dehydrate and filter the gas before it is used as fuel. It would typically be expected to include fuel gas filters, fuel gas heaters, orifice metering skid and gas chromatograph to measure the quality of the incoming gas. In addition it will include the various pipework headers to feed the two CCGT units. All of this equipment will be enclosed within a secure fenced off area, as shown on the indicative layouts.
4.3.63. The compound will be up to 4m height (12.5m AOD) and shall have a footprint of up to 53m by 18m.
Stacks
4.3.64. Combustion gases will be emitted to the atmosphere via two standalone stacks, located adjacent to the HRSG Building within the Generating Station Site. Based on dispersion modelling and an assessment of the potential impacts, the stacks will be 90m (up to 98.5m AOD). This is discussed in more detail in Chapter 11: Air Quality.
4.3.65. The primary release of emissions from the Proposed Development will be the exhaust gases produced from combustion of natural gas in the gas turbine, which will be regulated by the Environment Agency under the Environmental Permit required for the operation of the plant. The key components of the exhaust gases will be water vapour and carbon dioxide (CO2), with traces of oxides of nitrogen (NOx) and carbon monoxide (CO).
4.3.66. Emissions to air from the combustion process will be compliant with emission limits set within the EU Industrial Emissions Directive (IED) (Ref. 4-5), transposed into UK law by the Environmental Permitting Regulations (Ref. 4-6). The design and operation of the Proposed Development will minimise pollutant emissions including NOx through automated control of the combustion conditions.
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4.3.67. Flue gases discharged from the stacks will be monitored by an on-line continuous emissions monitoring system (CEMS), comprising a sampling system, analyser unit and data logger. The gas components measured will be, as a minimum, those stipulated by current legislation. Other gas components may be monitored for the purposes of process control. The components monitored are likely to include:
• NOX concentration;
• CO concentration;
• Oxygen concentration;
• Moisture content;
• Temperature; and
• Gas flow rate.
4.3.68. All of the parameters to be monitored will be documented in the Environmental Permit, and monitoring data will be submitted to the EA to demonstrate continued compliance.
4.3.69. A low intensity multi visual aviation light will be added to the CCGT stacks for use during night time, and colour contrasting visual markers for daylight hours to assist local aviation users.
Emergency Diesel Generators
4.3.70. Up to two emergency diesel generators approximately 1.5MW capacity will be located adjacent to the gas conditioning compound and workshops towards the south of the Proposed Development Site, within the Generating Station Site, for backup power to the onsite administrative buildings should the peaking plant not be built. The capacity of these generators is expected to be relatively small and will only be required as backup during a power failure onsite.
4.3.71. The generators will be supplied by fuel from the bulk distillate storage tanks located in proximity to the generators.
Gatehouse; Workshop, Store and Control Building’s
4.3.72. The gatehouse and main Site access will be located on the northern perimeter of the Proposed Development Site, near the eastern end of the Generating Station Site, with direct access from/to the Spine Access Road (currently under construction).
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4.3.73. The control building, workshop and stores are within the Generation Station Site south of the gatehouse. The existing 11kV line will be used to provide electricity to these structures.
Storage Tanks
4.3.74. A cooling water storage tank and towns water tank are required to provide cooling water supply. The tanks will be up to 25m diameter and up to 28m height (36.5m AOD) and would have the ability to maintain the CCGT units for a few hours in the temporary disruption of a water supply from the Bristol WWTW.
Waste Water Treatment Plant
4.3.75. The waste water treatment plant is indicatively located adjacent to the water storage tanks along the southern boundary of the Proposed Development Site and will be up to 6m in height (14.5m AOD). It is required to treat process water and sewage from the Site prior to discharge via the return water flow to the Bristol WWTW.
Distillate Storage/Offloading
4.3.76. An area for distillate storage and offloading is included in Development Parcel 1, to supply the peaking plant. This is discussed in more detail later in this chapter.
Water Treatment, Demineralised Water Storage Tank
4.3.77. A waste water treatment plant, water treatment plant, and demineralised water storage tank are included in Development Parcel 1 (adjacent to the administrative / control building in Figures 4-2 and 4-3 (Volume III)).
4.3.78. The water treatment plant is designed to purify the boiler feed water, prior to use, and constitutes a building up to 6m height (14.5m AOD) and with a maximum footprint up to 33m by 14m. The boiler feed water is temporarily stored in a tank up to 9m height and 9m diameter.
Fire Fighting and Safety Provisions
4.3.79. The Applicant will include appropriate fire protection based on standard requirements, best practice, its own experience and input from the local Fire Officer and insurers.
4.3.80. During the detailed design phase, a Hazard and Operability (HAZOP) assessment will be carried out by the design engineers to ensure that fire risks are controlled. Where appropriate, buildings will contain firewalls and the main plant building and diesel storage tanks are designed to be physically separate to any adjacent building.
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4.3.81. The fire fighting building and fire/ raw water storage tank are likely to be in close proximity to the workshop, store and control buildings located towards the north of the Site.
4.3.82. As required by relevant legislation, standards and codes of practice, all fire fighting equipment and detection and protection systems will be to the standard necessary to gain the approval from the Applicant’s insurers and the Fire Officer.
4.3.83. The fire protection and detection systems for the Proposed Development may include but not be limited to the following techniques:
• Fire pumps and raw water tank;
• Connection to the existing Seabank 1 & 2 Power Station Site fire water ring main;
• Automatic cut-off valves on all fuel pump lines;
• Smoke/carbon monoxide (CO) detectors;
• Heat, spark and flame detectors at strategic locations;
• Fire hoses, to be stored in trace heated enclosures;
• Fire extinguishers;
• Fire alarms;
• Emergency lighting; and
• Use of fire retardant materials.
The Cooling System (Development Parcel No 2)
4.3.84. There is a requirement for a cooling system to condense the steam used in the power generation process once it has been exhausted through the steam turbine, to allow it to be pumped back to the boiler for re-use.
Cooling Water System
4.3.85. A number of different options have been considered in order to provide adequate cooling for the Proposed Development, including direct wet-cooling technology, hybrid-cooling technology and dry-cooling technology. The alternatives and reasoning for the chosen technology is outlined in Chapter 6: Project Need and Alternatives.
4.3.86. Hybrid-cooling technology has been chosen as the preferred method of cooling for the Proposed Development and the technology that is considered to represent the use of Best Available Techniques (BAT) for the plant. This is essentially a combination of dry-cooling and wet-cooling. Hybrid cooling is more efficient than
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air cooling but has a lower water demand than direct cooling and less visual impact than the use of natural draught cooling water system.
4.3.87. The lower water demand means that a supply of grey water from the Bristol WWTW can be used for supply – as is done for Seabank 1 & 2 – rather than abstracting larger volumes of water directly from the estuary, which was considered but rejected due to the ecological and archaeological sensitivities of the estuary and foreshore. This balance between the efficiency and the water use has therefore been agreed with the EA to represent BAT for the Proposed Development.
4.3.88. Up to two banks each of 12 cells will be installed onsite, resulting in up to 24 cooling water systems. As noted in Tables 4-1 and 4-2, the height of these cooling water systems is up to 19m above ground level (up to 27.5m AOD); noticeably less than the turbine and HRSG buildings.
4.3.89. The maximum flow of water to/from the Proposed Development (excluding Seabank 1 & 2) will be 600m3/hr, or 170kg/s, although once the water is supplied it becomes a closed system and only requires top up for condensation and evaporative losses (which constitutes about 1% of the total flow). Only during specified maintenance purge events and blowdown is the entire volume flushed through the system and recharged.
4.3.90. Water returned to the WWTW is expected to be on average 25-26 degrees Celsius (°C) when the CCGT Plant is in operation, or ambient when the plant is offline.
4.3.91. Due to the water being received from the treated outfall of the WWTW, there may be trace pollutant concentrations in the water up to the permit discharge limits specified for the WWTW outfall. It therefore requires chemical treatment before use in the cooling system, as described below, together with the addition of towns water to potentially dilute the chemical concentrations. The water returned to the WWTW is therefore generally expected to be in a better condition than when received; in a similar way the water from Seabank 1 & 2 is reportedly currently used by the WWTW operator (Wessex Water) to dilute its discharge into the Severn Estuary under its current discharge consent. Processed effluent from the Proposed Development will also be mixed with the cooling water returns and returned to the WWTW.
Cooling Water Dosing System and Chemical Treatment
4.3.92. The water received from the Bristol WWTW will be treated onsite in a water treatment plant within a dosing area. Water treatment chemicals will be added to ensure the water meets design standards for use in the cooling water system, with towns water used to dilute the concentrations, when required. This is a
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separate system to the water treatment for the boiler feed and will be up to 4.5m height (12.5m AOD) and with a maximum footprint of 20m by 10m.
Cooling Water Switchgear Building
4.3.93. The cooling water switchgear building will be up to 5.6m in height (14.1m AOD) and with a maximum footprint of 31m by 12m, located immediately west of the cooling water system in the northwest corner of the Proposed Development Site, adjacent to the dosing system and chemical treatment.
Water Supply Infrastructure (Development Parcel No 6)
Water Supply Pipeline and Infrastructure
4.3.94. The Proposed Development will require a pipeline to supply water for the cooling water system. The proposed pipeline will supply both Seabank 1 & 2 and Proposed Development via a new 800mm diameter polyvinyl chloride (PVC) pipeline entering the southwest corner of the Seabank 1 & 2 station.
4.3.95. The pipeline will split into two lines at this point, a 560mm pipeline supplying Seabank 1 & 2, and a 560mm pipeline to be routed around the western and northern perimeter of the existing Seabank 1 & 2 station (within the existing fence line) to the northwestern corner of the Proposed Development Site, as shown in Figure 4-1a (Volume III). The pipeline will be laid a minimum 1.2-1.5m below ground, as described in Chapter 5: Enabling Works and Construction.
4.3.96. The two existing pipelines between the Bristol WWTW and Seabank 1 & 2 (currently used for supply and return) will both be used as a return line for the existing station and Proposed Development. In this way a single, larger diameter pipeline can be installed and the two existing pipelines utilised to support both power stations.
4.3.97. The return cooling water flow from Seabank 3 will transported within a second pipe up to 560mm diameter that runs around the perimeter of Seabank 1 & 2 along the same route as the feed pipe. It will 'T' into the existing Seabank 1 & 2 pipework just north of the existing station boundary.
4.3.98. The new cooling water pipeline, once outside of the Seabank 1 & 2 fence line, is likely to follow the route of the existing water pipelines which is shown in Figure 3-1, (Volume III of this PEI Report). The proposed pipeline will be laid at a minimum depth of approximately 1.2 - 1.5m below ground level. This route was selected as the preferred option to minimise impacts on existing known environmental sensitivities, to minimise land owner disruption and to minimise construction length. The routing presented in Figure 4-1b (Volume III of this PEI Report) is a routing corridor 30m wide, with some widening to facilitate potential
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minor route variations within that corridor in the event of site specific conditions or sensitivities identified during construction, and to enable laydown areas to be used along the route for stringing of the pipeline prior to installation and the temporary storage of spoil.
Towns Water
4.3.99. The Proposed Development will be supplied by towns water from Bristol Water through an off take from the pipeline currently within the Seabank 1 & 2 site. It is estimated that 25,000m3 of water year will be required each year to fill up the water storage tank, which takes around 12 hours each month.
Peaking Plant with ‘Black Start’ Capability (Development Parcel No 3)
4.3.100. A peaking plant, also known as a ‘fast response generator’ is included as part of the Proposed Development.
4.3.101. A peaking plant is used to quickly increase or ‘top up’ the generating capacity during periods of increased need by the National Grid. It can be fired up at short notice to help cope with periods of high demand or low supply nationally (for example, when the wind is not blowing sufficiently to provide adequate electricity from the increasing number of wind farms in the UK). National Grid and DECC have confirmed a national need for UK fast response capacity (see Chapter 6: Project Need and Alternatives).
4.3.102. It is proposed that up to 240MWe of export capacity is installed as part of the Proposed Development. There are two types of peaking plant engines that could be used – open cycle gas turbines (OCGT) or reciprocating engines. Both are fast response units but each has its own advantages.
4.3.103. At this stage, it is not possible to select a preferred technology for use in the Proposed Development and therefore the choice of technology is being left open at the consenting stage. For the purposes of the PEI Report and the final ES, the worst case potential environmental effect of each technology has been assessed, for example air emissions, noise emissions or building massing.
4.3.104. It is proposed that the peaking plant engines would be housed in up to two buildings, as shown in Figures 4-2 and 4-3 (Volume III of this PEI Report), with the building dimensions sized to accommodate either type of engine. The OCGT are self-contained and do not therefore need to be enclosed within a building envelope, reducing the height and massing of this structure. For the purpose of this PEI Report the worst-case parameters have been assessed within each technical chapter, which in most cases will constitute an enclosed building up to 24m above the finished ground levels.
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4.3.105. The largest commercially available reciprocating engine is of the order of approximately 18MWe, which means up to 13 engines would need to be installed to achieve the 240MWe output. The exhaust flues from each engine would be ducted together into one or two stacks to minimise the visual effects of the reciprocating engines.
4.3.106. The largest commercially available OCGT is of the order of approximately 120MWe. The OCGTs are inherently enclosed within a prefabricated metal structure.
4.3.107. The peaking plant will be limited to a maximum of 1,500 hours per year and will have an efficiency around 40-45%. Based on the maximum permitted availability, the peaking plant would use approximately 24,000m3 of natural gas fuel per year.
4.3.108. The peaking plant would also provide the capability of being able to ‘black start’ the CCGT units without any assistance from the national electricity grid in the event of a total or partial shutdown of the national transmission system. The Proposed Development could then be used to help restart the national transmission system, whereas power stations without black start capability need to draw power from the transmission system to start operation.
4.3.109. A black start event would be an abnormal event, during which time the peaking plant would operate on distillate fuel. Once the CCGT units are operational the peaking plant would switch to natural gas. This process is estimated to take as little as 10 minutes and would therefore be a short-term, infrequent event.
4.3.110. The distillate fuel (for black start) would be stored onsite in up to two above ground bunded tanks within Development Parcel 1, typically cylindrical and each of up to 10m diameter by up to 12.5m height (21.0m AOD).
Utilities, Services and Landscaping Area (Development Parcel No 4)
Utilities and Services
4.3.111. A number of utilities current exist within the Proposed Development Site, which needs to be avoided or diverted.
4.3.112. The Abson gas pipeline, operated by National Grid Gas, which broadly crosses the Proposed Development Site in a southeast to northwest orientation, will need to be realigned as part of the enabling works described in Chapter 5: Enabling Works and Construction.
4.3.113. The diversion will be underground within the Utilities, Services and Landscaping Area, although it is a possibility that the pipeline may be brought above ground within the Site fence line, and will follow the route within the Utilities, Services and Landscaping Area that is south of the Generation Station Site (denoted on
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Figures 4-2 and 4-3 (Volume III of this PEI Report) to Seabank 1 & 2. If the pipe is installed above ground, the diverted gas pipeline will be placed on pipe racks approximately 1m wide and 2m high, as explained in Chapter 5: Enabling Works and Construction.
4.3.114. Subject to confirmatory engineering works being undertaken by National Grid, it is not currently expected that any substantial upgrades will be required to the network to deliver the necessary gas supply to the Proposed Development in addition to Seabank 1 & 2.
4.3.115. There is also an abandoned private water main that runs south-north across the Generating Station Site, which will require decommissioning prior to construction.
4.3.116. Both the diversion of the Abson gas pipeline and decommissioning of the water pipeline are further described in Chapter 5: Enabling Works and Construction.
Landscaping Works
4.3.117. Figure 17-15 (Volume III of this PEI Report) illustrates an indicative landscape masterplan for the Proposed Development, based on the maximum design parameters outlined in Table 4-1. In effect, this represents a worst-case scenario for the availability of areas for landscaping on-site; more land would be available if the final structures are less than the maximum dimensions illustrated above.
4.3.118. An 8m easement will be reserved along the length of the diverted Red Rhine channel, which Severnside Distribution Land Ltd is currently installing, to facilitate maintenance work by the LSIDB. It is intended that this would retained at existing site levels and would mainly comprise grassland, with some ruderal vegetation.
4.3.119. Elsewhere, a mixture of grassland, ruderal vegetation, and trees and shrubs will be planted.
4.3.120. The Utilities, Services and Landscaping Area will also contain the surface water attenuation needed to achieve pre-development greenfield rates for rainfall events up to and including the 1 in 100 year (inclusive of climate change). The surface water runoff generated within the Proposed Development Site will drain via a positive drainage system to an attenuation feature, or multiple features, with total capacity up to an estimated 3,800m2 (assuming an average 1m depth).
4.3.121. Figures 4-2 and 4-3 (Volume III of this PEI Report) show the current preferred layout for the water attenuation, which is a single water body, located between the gas receiving station and CCR Site. A linear water feature may also be incorporated along the southern boundary of the CCR Site adjacent to the PROW, as illustrated in Figure 4-2 and 4-3 (Volume III of this PEI Report) . This is shown in addition to the 3,800m3 requirement on the layout drawings, although
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it could enable the reduction of the size of the water body adjacent to the gas receiving station at the detailed design stage.
Watercourse Diversions (excluding the Red Rhine), Internal Roads and Access
Surface Water Drainage
4.3.122. Internal surface water drains will be required to transport surface water runoff to the proposed attenuation areas prior to discharge from the Site into the Red Rhine (via oil interceptors).
4.3.123. In the event of a fire, the firewater would be directed towards the attenuation pond and an electronic valve would automatically shut off the flow from entering the Red Rhine until it had been tested and deemed acceptable.
4.3.124. The DCO Application does not include the creation of the new Red Rhine channel. This is being undertaken by third party (Severnside Distribution Land Ltd) as part of their works to develop the wider Severnside area under the extant 1957/58 consent. The trenching of the new channel will be undertaken independently of the DCO Application and has been considered as part of the ‘future baseline’ as opposed to being ‘associated development’ to this Proposed Development, as discussed in Chapter 7: Assessment Methodology.
4.3.125. The diversion of the water flow from the existing Red Rhine channel into the new channel does form part of this DCO Application, as well as the diversion of a drainage ditch within the Site from the land to the south known as Crook’s Marsh.
Security Fencing
4.3.126. There will be a fence line around the perimeter of the Generating Station Site installed with closed circuit television (CCTV).
4.3.127. A gatehouse reception will be constructed at the northern perimeter of the Proposed Development Site where traffic will exit to the Spine Access Road, which will be manned 24-hours per day.
4.3.128. In the event that the Spine Access Road is not constructed, the primary access will be through Seabank 1 & 2 site, in the northwest corner of the Proposed Development Site. It is considered unlikely that the Spine Access Road will not be completed however, given that its construction is partly underway and for the purposes of this PEI Report it has been assumed to be in place by the time of construction of the Proposed Development.
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Car Parking and Cycle Storage Facilities
4.3.129. Operations staff will enter the Proposed Development Site via the new Spine Access Road through the main entrance in the centre of the Proposed Development Site. The access points are discussed in more detail later in this chapter.
4.3.130. Car parking facilities will be provided along the northern perimeter, with approximately 4 spaces next to the gatehouse, and remaining 15 behind the control, workshop, store and admin buildings.
Internal Roadways and Footpaths
4.3.131. There will be internal roadways within the Generation Station Site connecting infrastructure and access points.
4.3.132. There will be five vehicular access points to the Proposed Development Site during operation, as illustrated in in Figure 4-7 (Volume III of this PEI Report).
4.3.133. The main operational access route to the Proposed Development Site will be through the northern east perimeter of the Generating Station Site [Access Point 3, Figure 4-7 (Volume III)] via a proposed new Spine Access Road which Severnside Distribution Land Ltd intends to construct under the extant 1957/58 consent (currently under construction).
4.3.134. Secondary access to the road may also be constructed from the south along Ableton Lane [Access Point 5], although this is likely to be pedestrian or emergency vehicle access only.
4.3.135. Secondary access will also exist through the eastern perimeter of the CCR Site from an existing roundabout that will connect to the new Spine Access Road [Access Point 1], as well as at a second point further west along the Spine Access Road adjacent to the main access point [Access Point 2].
4.3.136. Direct access to the Site will also be available from Seabank 1 & 2 via an entrance in the northwest corner of the Proposed Development Site. In the event that the new Spine Access Road is not completed in time, this would be the main access point to the Site [Access Point 4].
4.3.137. As discussed above, an 8m easement will be left along the southern boundary of the diverted Red Rhine within the Proposed Development Site for access for maintenance by the LSIDB.
4.3.138. There are currently no PROWs within the Proposed Development Site, although a PROW currently terminates at the southern boundary of the Proposed Development Site.
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4.3.139. The Proposed Development will incorporate a new 3m wide footpath/ cycle path and 3m wide bridleway running form Ableton Lane, along the Utilities, Services and Landscaping Area in an easterly direction, and terminating at the existing roundabout that lies immediately east of the Proposed Development Site.
Lighting Columns and Lighting
4.3.140. The type, number and location of external lights for the operational phase will be carefully considered to take into account and minimise potential impacts to local residents and wildlife. All lighting will be implemented to minimise disturbance to important ecological receptors. The choice and implementation of lighting will be designed in line with current best practice for the reduction of intrusive light and avoidance of light pollution (e.g. Institution of Lighting Professionals (2011) ‘Guidance Notes for reduction of Intrusive Light GN01’) and seek to result in no significant additional off site light emission from the Proposed Development Site compared to the present situation.
Carbon Capture Readiness Land (Development Parcel No 5)
4.3.141. The potential future need for the installation of CCS technology and transport of CO2 off-site does not form part of this DCO Application. Any such works required for installation of CCS technology at some point in the future would be subject to separate planning consent or DCO consent as appropriate.
4.3.142. For the purposes of this DCO Application and in accordance with UK requirements, CCS will be considered through preparation of a standalone supplementary report to the DCO Application that addresses the requirements of the DECC CCR Guidance (Ref. 4-4).
4.3.143. In accordance with UK CCR requirements, the DCO Application incorporates an area set aside for the potential future installation of Carbon Capture technology. It is recognised that technological progress and developments in the regulatory framework for the use of carbon capture technology are likely to occur within the lifetime of the Proposed Development. Therefore, the design of the new power station has been developed with consideration for the possible future retrofitting of carbon capture technology at some future date.
4.3.144. The CCR requirement means that Applicants must demonstrate that CCS technology (of which there are 3 key types: pre-combustion capture, post-combustion capture and oxy-fuel combustion) has been considered as part of the DCO Application and that there is sufficient land available and remaining available for the future retrofit of that technology in the event that it is commercially proven at some point in the future, i.e. that the Proposed Development is considered Carbon Capture Ready (CCR).
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4.3.145. CCR needs to be demonstrable for all new generating stations with a generating capacity at or over 300MW and of a type covered by the European Union Large Combustion Plant Directive as set out in section 4.7 of the Overarching NPS for Energy (EN-1).
4.3.146. As such, an approximate area of 6.3ha denoted the CCR Site has been reserved to the east of the Generating Station Site (see Figure 3-1, Volume III of this PEI Report) to allow for the potential future provision of CCS technology. Any future installation of carbon capture technology would be subject to a separate formal consent application at the time, since the details associated with any such technology are not yet available. For the purposes of this DCO Application therefore, only a high level evaluation of carbon capture readiness has been undertaken in accordance with the CCR requirements (presented as a separate, standalone report to the final ES).
4.3.147. This CCR Site will be temporarily used for siting of the construction compound and laydown during the generating station construction phase. This area will accommodate construction work force welfare facilities, construction laydown area, security gatehouse, internal roadways and footpaths as well as lighting. This is further discussed in Chapter 5: Enabling Works and Construction.
4.3.148. Post construction, the CCR Site will be reinstated to grassland, with relatively little or no other vegetation, hence returning it to a similar state to its current baseline. The ecological value of this land will be maintained in accordance with the CCR Directive (Ref. 4-3), which states that “the land would not be available for long term mitigation’ and ‘not allowed to become a wildlife reserve through neglect or mismanagement”.
Grid and Utility Connections (Development Parcel No 7)
4.3.149. The Proposed Development will require a connection to the existing Seabank Substation to export the electricity generated by the power station, as described below. The information relating to the proposed grid connection will also be presented in the Grid Connection Statement that will accompany the DCO Application.
Electricity Substation and Grid Connection
4.3.150. The Proposed Development will export electricity to National Electricity Transmission System (NETS) via the existing Seabank 400kV substation. A grid connection agreement for 1,200MWe from 31 October 2019 is already in place with National Grid (the administrating and operating authority of the NETS) and the Applicant is seeking to extend this by an additional 200MW.
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4.3.151. Two separate connection circuits will link the Proposed Development 400kV switchyard to the Seabank Substation.
4.3.152. The electrical connection will extend approximately 440m south of the Proposed Development Site, through existing Seabank 1 & 2 site (within the fence line), to the Seabank Substation.
4.3.153. It is envisaged that the connection would be via above ground cables, on an aerial cable bridge rack approximately 2m above ground to avoid existing equipment within Seabank 1 & 2. However the option for Horizontal Directional Drilling (HDD) beneath the Seabank 1 & 2 infrastructure remains a possibility and has also been assessed in the EIA. Further information on construction methods is provided in Chapter 5: Enabling Works and Construction.
4.3.154. The connection infrastructure that will also be constructed by the Applicant as part of the Proposed Development will comprise the following main elements:
• Up to five generator transformers to step-up the voltage to 400kV;
• 400kV gas-insulated switchgear ("GIS") connecting the output from the generator transformers to the two connection circuits within the Proposed Development Site;
• Two generator connection bays with GIS to connect the 400kV connection circuits with the 400kV substation busbars at Seabank substation; and
• A fibre optic cable that will also be installed with the power cable circuit to carry essential control and protection data as well as telecommunications data to satisfy National Grid requirements.
4.3.155. In parallel with – but separate to - this DCO Application, National Grid is currently proposing the connection of an additional 400kV circuit into Seabank Substation for the network reinforcement required for the proposed Hinkley C nuclear power station, which will include the extension of the existing substation building and associated foundations will accommodate five new bays.
4.3.156. The plans by National Grid are independent from this DCO Application and are not considered ‘Associated Development’ to the Proposed Development. They are discussed in terms of cumulative impacts in each technical assessment where appropriate. Further information is presented in Chapter 7: Assessment Methodology.
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Towns and Foul Water Connections
4.3.157. Development Parcel 7 includes an approximately 100m wide corridor within the northern boundary of the Seabank 1 & 2 site within which to connect the Proposed Development to the towns water and foul water services.
4.3.158. The foul water will be treated onsite in the WWTP and discharged into the return flow pipe with the cooling water to the Bristol WWTW.
Ancillary Development
4.3.159. The Planning Act 2008, Section 120, defines ‘ancillary development’ as a range of matters including acquisition of land, intrusive works and other connections and agreements. These will be considered and documented in the DCO application
4.4. Hours of Operation and Shift Pattern
4.4.1. It is envisaged that plant operation will be a continual process, operating twenty-four hours per day, seven days per week with periodic offline periods for maintenance.
4.4.2. As mentioned previously, the actual running hours will be subject to the electrical demand, however based on current projections it is anticipated that the CCGTs will operate at around a 31% load factor (an average 2,716 hours per year) over the course of the plant lifetime. However, for fuel capacity purposes and conservative assessment purposes, it is assumed that 90% availability is achieved.
4.4.3. The plant will be designed to operate continuously for an expected period of at least 30 years after which on-going operation will be reviewed and if it is not appropriate to continue operation the Proposed Development Site will be decommissioned.
4.5. Employment
4.5.1. It is estimated the Proposed Development if operated independently of Seabank 1 & 2 will provide approximately 40 full time equivalent (FTE) operational jobs, as summarised in Table 4-3. If the Proposed Development was operated in conjunction with Seabank 1 & 2, approximately 22 additional staff would be required.
4.5.2. Given the nature of power station operation, it is likely that the employees will be working in shift patterns, with approximately 4 employees per shift (depending on fuelling operation) and the remainder in normal working hours roles. There would be three shifts per day, with the first shift starting at 06:00 hours.
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Table 4-3: Provision of Employment during Operation Position Number Skill Level
Shift Operative 12 Level of expertise comparable to existing boiler/turbine operators
Maintenance Controller 2 Level of expertise comparable to existing fuel
operatives Operations Technician 12 Degree qualified mechanical engineer
Maintenance Technician 8 Craftsman level
Chemist 2 Commercial position Corporate 4 Assistant level Total 40 -
4.5.3. In addition, temporary and contractor employees associated with fuel deliveries and maintenance activities will be required for the operation of the Proposed Development.
4.6. Nuisance Control
4.6.1. Lighting of the Proposed Development Site is required for security and safety purposes and will meet the reasonable requirements of the local authority to avoid impacts upon local residents and road users. This is discussed further in Chapter 17: Landscape and Visual.
4.6.2. Noise levels will be regulated as defined in Section 72 of the Control of Pollution Act 1974 (amended 1989) (Ref. 4-7) and conform to British Standard ISO 140-4 (1998) and those detailed within any Requirements as part of the DCO. An annual noise survey will be carried out onsite and any noise complaint will be investigated and addressed. This is discussed in more detail in Chapter 12: Noise and Vibration.
4.6.3. As the generating station will be fired on natural gas, the potential for dust emissions during operation will be low. During construction, there is the potential for dust generation from any soil clearance activities and the importation and levelling of material for land raising, for example. Mitigation measures are presented in Chapter 11: Air Quality.
4.7. Operational Waste Streams
4.7.1. This section discusses the potential for operational waste. Construction waste is discussed in Chapter 5: Enabling Works and Construction.
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4.7.2. During the operational phase there is not expected to be any significant waste associated with the Proposed Development. The key waste streams include those outlined in Table 4-4.
4.7.3. Waste water generated from cooling and boiler blowdown is described further in Chapter 14: Flood Risk, Hydrology and Water Resources. During commissioning, boiler acid washes will be required. For the boiler acid washes the volume is effectively the volume of the boiler, plus a rinse. This is estimated at around 1,200m3 of waste liquid during commissioning, which will be neutralised and tankered offsite.
Table 4-4: Expected Waste Streams associated with the Operational Proposed Development Waste Description Quantity (tonnes per
year) Management
Oil from oil/water separators (liquid) 0.5 Recycled
Sludge from oil/water separators (solid) 3 Recycled
Transformer oils 20-30 Recycled Oil filters 1 Special waste landfill Oil contaminated material 2 Special waste landfill Batteries (lead) 0.25 Special waste landfill Fluorescent tubes and lamps 0.4 Special waste landfill Biodegradable wastes (grass etc.) 3 Recycled
Air filters 5 Municipal landfill Sewage sludge 120 Sewage treatment plant Timber (packaging) 7 Recycled Mixed metal waste 5 Recycled Turbine and blade washings 15 Sewage treatment plant Waste oil 5 Recycled
General waste 25 Part recycled at MRF / municipal landfill
Glass 2 Recycled Ion exchange resins 15 (5year cycle) Recycled
4.8. Chemical and Utility Usage
4.8.1. Table 4-5 summarises the anticipated chemical usage during operation.
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Table 4-5: Utility Usage
Utility Consumption Yearly
Units Value
CCGT Cooling Water tonnes 6,000,000
CCGT Electricity (Auxiliaries) kWh (kilowatt hour) 350,000,000
CCGT Diesel (Emergency Generators) m3 20
CCGT Nitrogen m3 4,000
Demineralisation
Scale Inhibitor kg 60,000
Sulphuric Acid kg 280,000
Caustic Soda kg 40,000
Chlorine kg 30,000
Cooling Water System
Glycol kg 60,000
Corrosion Inhibitor kg 15,000
Antibacterial agent kg 3,500
Steam Cycle
Ammonia kg 10
Oxygen Scavenger kg 1,500
Tri Sodium Phosphate kg 30
4.9. Safety and Emergency Planning
4.9.1. The Proposed Development could potentially be operated by the existing Seabank 1 & 2 Operations and Maintenance teams and will utilise external expertise from the equipment vendors and specialist advisors when required.
4.9.2. The Applicant will develop an Emergency Planning and Response Management Plan similar to that used for Seabank 1 & 2 site such that emergency planning and response control measures are implemented to:
• Mitigate the potential effects to persons, environment, assets or company reputation;
• Respond to catastrophic plant and process incidents such as fires, explosions, release of hazardous substances or large releases of energy;
• Respond to external incidents which have the potential to cause incidents described above e.g. nearby facility emergency, flood, malevolent actions, earthquake or aircraft crash; and
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• Communicate with stakeholders such as neighbours, media or regulators.
4.9.3. The Emergency Planning and Response Management Plan will be tailored to the Proposed Development. This Plan is applied at all operational SSE sites and includes any site specific requirements.
4.9.4. Fire safety methods will build upon those methods already practiced at the Seabank 1 & 2 site. Fire safety management is applicable to the entire Generation Station Site and is further addressed in this section.
4.9.5. Measures will be taken to minimise the risk of fire during site enabling, construction, operation and decommissioning. The precise nature of these measures will be determined following detailed engineering. The key potential fire risk aspects of the Proposed Development are:
• Storage of distillate fuel; and
• Storage of flammable consumable materials (e.g. maintenance oil).
4.9.6. Consumable materials will be stored in bunded controlled areas and storage volumes will be minimised where possible. Due consideration will be paid to the appropriate legislation and guidance.
4.10. References
Ref. 4-1 DECC (2011) Overarching NPS for Energy (EN-1) Ref. 4-2 The Planning Inspectorate (2012). Advice Note 9: Rochdale Envelope Ref. 4-3 Official Journal of the European Union (2009) Directive 2009/31/EC of
the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide
Ref. 4-4 DECC (2009); Carbon Capture Readiness (CCR), A guidance note for Section 36 Electricity Act 1989 consent applications
Ref. 4-5 European Commission (2010) Industrial Emissions Directive (IED) Ref. 4-6 The Environmental Permitting (England and Wales) Regulations 2010 Ref. 4-7 HMSO (1974); Control of Pollution Act (amended 1989)
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5. Enabling Works and Construction
5.1. Introduction
5.1.1. This chapter of the PEI Report presents an overview of the enabling works
required for the preparation and construction of the Proposed Development and
associated infrastructure. A description of the operational development is
provided in Chapter 4: Project Description.
5.1.2. Enabling and construction works are anticipated to last approximately 4 ½ years.
An indicative construction programme is presented in Section 5.3.
5.1.3. A Construction Environmental Management Plan (CEMP) will be produced and
implemented prior to the onset of the construction phase to maintain
consideration of environmental effects beyond the consenting stage of the
Proposed Development and associated infrastructure. The appointed
construction contractor will be required to adhere to the CEMP, which will give
due regard to the sensitive environmental receptors as identified within each
technical chapter. A framework for the CEMP is provided in Appendix C, Volume
II of this PEI Report, which will be populated and agreed with SGC and BCC
following receipt of the DCO and prior to enabling works commencing onsite.
5.2. Enabling Works
5.2.1. There are currently no buildings/structures located in the DCO Site, therefore no
demolition works will be required as part of this Proposed Development and
associated infrastructure.
5.2.2. There are a few ash trees and shrubs within the Proposed Development Site,
which will be removed following the appropriate permissions and ecological
checks; the need for compensatory planting at another location has been
assessed as part of this EIA and is discussed in Chapter 16: Ecology.
5.2.3. The disused railway tracks in the northwest corner of the Proposed Development
will also require decommissioning. These abandoned tracks will be dug up and
removed from the Site before any of the following works.
Contractor Laydown/Accommodation
5.2.4. The CCR Site will be levelled and gravelled at the start of the construction
programme in preparation for laydown and Contractor accommodation.
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Diversion of Existing Services within the Proposed Development Site
5.2.5. It will be necessary to divert some of the existing on-site services and utilities in
order to construct the Proposed Development and associated infrastructure,
which are illustrated in Figure 3-3, Volume III of this PEI Report.
Water Main
5.2.6. There is a redundant private water main that runs south-north across the
Generating Station Site which used to serve the former Terra Nitrogen and ICI
site. For a single-shaft generating station this water main would need to be
diverted, as it is currently running below the location in which the HRSGs are
proposed to be located. For a multi-shaft arrangement it may be possible to
construct around this water main and avoid the need for it to be diverted. This
pipeline will be surveyed /located and, either decommissioned in-situ with a new
pipeline installed to divert the flow round the Proposed Development, or a trench
(approximately 3-5m wide) opened to excavate the pipe which will be removed
and decommissioned.
Abson Gas Pipeline
5.2.7. Diversion will be required to the Abson gas pipeline which broadly crosses the
Proposed Development Site in a southeast to northwest orientation.
5.2.8. The National Grid ‘F14 feeder’ does not require diverting and is therefore not
discussed further below.
5.2.9. The Abson gas pipeline runs from the southeast corner of the Proposed
Development Site and crosses to the southwest corner, before rising above
ground in the northeast corner of the Seabank 1 & 2 site. The pipeline transports
gas from Abson to Severnside and runs through areas designated for
development and will require diverting.
5.2.10. It is recorded on the pipeline route map that the pipeline through the Proposed
Development Site was installed by Horizontal Directional Drilling (HDD), in two
drills, to allow it to pass under an existing 24” water main and other buried
services on the site. Based on HDD profile drawings, the gas pipeline will be at a
depth of around 10m across much of the Site.
5.2.11. The Abson pipeline will be surveyed /located and cut in the eastern part of the
Proposed Development Site. New pipe spools will be installed using trenching
techniques to divert the Abson pipeline within the Utilities, Services and
Landscaping Area, as illustrated in Figure 4-1a, Volume III of this PEI Report).
The trench would be approximately 3-5m wide 4m deep, within a 20m
construction corridor. Once within the Site fence line the gas pipeline will either
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continue below ground or will be laid on a pipe rack approximately 2m above
ground level (up to 10.5m AOD). The existing pipeline would be left in-situ
beneath the Proposed Development Site.
Overhead Lines
5.2.12. It will be necessary to divert an 11kV overhead line (OHL) that currently crosses
the eastern edge of the Generating Station Site in a northeast to southwest
direction.
5.2.13. Western Power Distribution will undertake the diversion, installing it underground
through the centre of the Site, most probably alongside one of the internal access
roads. The exact route of the cable will be determined during the detailed design.
5.2.14. The 400kV and 132kV OHLs that cross the Proposed Development Site will not
be diverted.
Diversion of Red Rhine
5.2.15. As mentioned previously within Chapter 4: Project Description, the DCO
Application requires the diversion of the water flow from the existing Red Rhine,
to a new channel located outside along the northern boundary of the Proposed
Development.
5.2.16. The water flow will be diverted using earth bunding within the existing Red Rhine
to allow the flow to move into the dry channel. Only when the new channel has
been stabilised will the existing Red Rhine will be dewatered and filled in.
Land Raising
5.2.17. For flood protection purposes, it is expected that the Generating Station Site will
need to be raised up to 8.31m AOD (an average 2.0m rise in ground level).
However in order to provide sufficient flexibility for the Contractor who may be
unable to guarantee a finished level to this level of precision, the DCO Application
allows for a finished ground level up to 8.5m AOD within the Generating Station
Site, as illustrated in Figure 5-1 (Volume III of this PEI Report). The justification
for this is presented in Chapter 13: Flood Risk, Hydrology and Water Resources.
5.2.18. Other parts of the Proposed Development Site and the Other DCO Land do not
require raising for flood protection.
5.2.19. It is estimated that circa 158,000m3 of material will be required to raise the Site,
depending on whether the entire Generating Station Site is raised to a consistent
8.5m AOD level. It has been assumed that this material will be imported over a 6
month time period (to avoid significant effects on the local road network), and that
all material will be transported to site by road.
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5.2.20. The fill would arrive in loads with a minimum capacity of 10m3, which would result
in approximately 15,800 additional HGVs entering/leaving the Proposed
Development Site per day. The effect of this on traffic flows on the public
highways is discussed in Chapter 10: Traffic and Transport.
5.2.21. This is a worse case assumption; it is expected that the finished site levels will be
less than this elevation to allow the Contractor to lay a 300-550mm gravel or
concrete bed in order to achieve a finished floor level of 8.31m AOD, and certain
infrastructure such as the cooling water system is inherently bunded and could be
constructed at current site levels without the need for any land raising.
5.2.22. It should be noted that if the finished ground level when built is less than 8.5m
AOD, the maximum height of the structures and stacks can also reduce.
5.2.23. The topsoil will be stripped, stockpiled and retained for landscaping prior to land
raising.
Proposed Cooling Water Pipeline
5.2.24. As outlined in Chapter 4: Project Description, a new cooling water pipeline will be
required from the WWTW, approximately 3.5km south of the Site (as the crow
flies). This pipeline will be approximately 4.5km and will be buried a minimum 1.2-
1.5m underground.
5.2.25. For the purposes of the DCO Application the cooling water pipeline is considered
to be Associated Development to the Proposed Development as defined under
Part 3 to the Planning Act 2008. The necessary easements and permissions for
the construction of this pipeline will therefore be sought under the DCO.
5.2.26. It is intended that the water pipeline would be constructed and owned by Wessex
Water. Article 6 of the draft DCO would allow the Applicant to grant or transfer
any of the benefit of the provisions of the DCO to another entity. Any benefits or
rights conferred this way would be subject to all the same liabilities and
obligations as under the DCO.
5.2.27. The indicative routing corridor of the proposed cooling water pipeline is shown in
Figure 4-1a and Figure 4-1b (in Chapter 4: Project Description).
5.2.28. In preparation for laying the cooling water pipeline, the following key pre-
construction processes will be performed:
• Liaison with key local stakeholders and potentially affected landowners;
• Completion of a pre-construction survey to:
o Mark out the pipeline construction corridor, third party services and
the need for any other special crossings; and
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o Provide a photographic record of the entire route including key
operational and environmental features and aspects.
• Completion of additional environmental surveys required (e.g. post
consenting surveys);
• Evaluation and implementation of agreed pre-construction environmental
mitigation measures;
• Marking of all crossing points of buried services and any environmental
resources to be protected;
• Excavation of trial holes along key points of the route to confirm the
suitability of localised underlying ground conditions;
• Establishment of temporary access tracks along the construction working
width (including bridging of existing ditches to provide temporary working
access where required); and
• Implementation of security and health and safety arrangements, such as
the provision of signage and infrastructure.
5.2.29. Once the pre-construction activities have been completed the works required to
install the proposed cooling water pipeline would commence. These are outlined
in section 5.3 of this chapter.
5.3. Construction Phase
5.3.1. Measures for site preparation and construction are necessarily broad at this
stage and may be subject to modification during any future detailed construction
planning. For this reason, the following assessment is based on an envelope of
works and reasonable assumptions for the construction programme and the
collective experience of the EIA and Design Team with similar projects,
particularly in relation to the phasing of the Proposed Development and
associated infrastructure.
5.3.2. Potential construction environmental effects identified within this chapter are
discussed in more detail in each of the corresponding technical chapters (i.e.
Chapters 9 to 19).
Programme of Works
5.3.3. Allowing sufficient time for the granting of DCO consent and to address expected
requirements, it is anticipated that the earliest enabling works would be mid 2015,
with a commissioning date in late 2019. It is the current intention though that the
DCO should allow sufficient flexibility for the construction to start anytime within 7
years of receipt of the Order, which would be anytime between 2015 and 2023.
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The Applicant’s current best estimate though is that it will target a 2021
commissioning date.
5.3.4. The main activities to be undertaken and the approximate duration of the works
are outlined in Table 5-1. Table 5-1 presents an indicative programme for the
construction works; however the actual programme will be subject to contractor
specifications.
5.3.5. Both the enabling works and construction total approximately 4 ½ years
(approximately 54 months), based on the Applicant’s current best estimates.
5.3.6. Enabling works are anticipated to require approximately 17 months and be
complete by 2019. The subsequent construction and commissioning phase will
having an estimated minimum duration of around 37 months, assuming the entire
Proposed Development is built rather than using a phased approach. Depending
on market conditions the Applicant may prefer to construct the Proposed
Development in phases over a longer period of time, or delay the start date in line
with the requirements of the DCO.
5.3.7. Based on current estimates, the peak period of construction is expected to occur
in late 2019, which represents the initial construction of the Generating Station
Site.
5.3.8. A Principal Contractor will be appointed by the Applicant for the works and they
will be held responsible for the implementation of a Construction Method
Statement (CMS) and the CEMP, through which compliance with The
Construction (Design and Management) Regulations (2007) (Ref. 5-1) will be
achieved.
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Table 5-1: Indicative Enabling and Construction Programme
2017 2018 2019 2020 2021
Activity Weeks
EN
AB
LIN
G W
OR
KS
Leveling of CCR Site and preparation for laydown
26
Diversion of existing utilities
26
Diversion of Red Rhine watercourse
26
Preparation and Land Raising
60
CO
NS
TR
UC
TIO
N
Generating Station Site
144
Peaking Plant 12
Cooling Water Pipeline
96
Electrical Grid Connection Infrastructure
4
Landscaping 52
Commissioning 4
Hours of Work
5.3.9. It is anticipated that the core working hours for construction will be as follows:
• 07:00 – 19:00 hours weekdays;
• 07:00 – 13:00 hours Saturday; and
• Working on Sundays and Bank Holidays will be subject to reasonable
notice.
5.3.10. It is likely that some construction activities will be required to be 24 hours during
the peak periods; therefore this has formed the basis of the assessments
contained within this report, unless specified otherwise. Where on-site works are
to be conducted outside the core hours they will comply with any restrictions
agreed with SGC and/or BCC, and in particular regarding control of noise and
traffic.
5.3.11. Some technical chapters assume deliveries outside these hours to present worse
case scenarios.
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Construction Workforce
Proposed Development
5.3.12. It is estimated that during construction, there will be a maximum of 800 personnel
contracted to work onsite on any given day. Plate 5-1 illustrates that the
personnel resource is expected to peak around two years into the construction
schedule, which based on Table 5-1 is envisaged to be during the second to
fourth quarters of 2019.
5.3.13. Chapter 10: Traffic and Transport discusses the transport options available to
employees for travel to and from work.
Plate 5-1: Estimated Personnel Onsite during Construction (Post Enabling Works)
Associated Development Infrastructure
5.3.14. It is expected that approximately 100 additional workers to the numbers
presented above will be required during construction of the cooling water pipeline
and electrical connection.
5.3.15. The construction period for the cooling water pipeline is anticipated to be
throughout 2020 to 2021 and to take approximately 24 months to complete. The
electrical connection will run over a 4 week period within this timeframe.
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5.3.16. Consideration has been given to the types of plant that are likely to be used on-
site during the site preparation and construction phase of the Proposed
Development and associated infrastructure. The plant and equipment associated
with each key element of the construction process is set out in Table 5-2. The
table also includes the maximum number of mobile work plant required at any
one time during the construction programme.
Table 5-2: Estimated Plant Type and Equipment during Construction Activities
Plant
Number of Plant
Proposed Development
Associated Infrastructure
360 Excavator 5 5
Bulldozer 6 1
Dumper 6 3
Paver 8 -
Roller 3 -
Crane 4 -
Compressors 6 1
Cherry Pickers 8 1
Hoists 3 1
Fork Lift Trucks 4 -
Concrete Delivery Trucks 25 -
Concrete Pumps 2 -
Heavy Goods Vehicles (HGVs) (delivering and collecting)
6 4
Piling Rigs 4 -
Generators 5 -
Pumps 2 1
Tipper Wagons - 3
Road Vechles - 1
HDD Drilling rig - 1
Laydown and Contractors Compound Areas
5.3.17. It is proposed that the laydown and contractors compound areas will be located in
an area of approximately 4ha in the eastern side of the Proposed Development
Site. 3ha of this area will be located in the CCR Site (see Figure 5-2, Volume III
of this PEI Report), with the remainder in part of the proposed Utilities, Services
and Landscaping Area.
5.3.18. Construction material for delivery and storage will be located in the northern
border of the CCR Site to avoid material having to pass under the existing
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overhead power lines. The chemical and flammable storage area/ services hub
(power/water/sewage) and secure equipment storage will all be located on the
western side of the CCR Site. The contractor compound, including approximately
40 cabins, will be located in the northeast of the CCR Site. A temporary car park,
with a maximum capacity of approximately 400 spaces, will be located to the
southeast of the CCR Site, with entrance/exit from Access Point’s 1 and 2.
5.3.19. The laydown and contractor areas will be connected with a temporary access
road, as illustrated in Figure 5-2, Volume III of this PEI Report.
5.3.20. The laydown area within the CCR Site will also be used for storing the cooling
water pipeline materials. Additional laydown and spoil material stockpiles could
occur anywhere along the Other DCO Land, adjacent to the proposed pipeline.
5.3.21. Following the end of construction, the laydown and contractor areas on the CCR
Site will be reinstated to grassland using the stored top soil that was stripped at
the start of construction. The ecological value of this land will not be improved as
the EU CCS Directive Guidance (Ref. 5-2) states that “the land would not be
available for long term mitigation’ and ‘not allowed to become a wildlife reserve
through neglect or mismanagement”.
5.3.22. Additional laydown areas required along the cooling water pipeline will be
reinstated as detailed in paragraph 5.3.57.
Transportation of Material and Equipment
5.3.23. Transportation of construction material to and from the DCO Site will be via
existing trunk and local networks (A4 and A403) Deliveries of construction
materials will predominantly be by HGVs.
5.3.24. The peak number of vehicle movements is expected to occur during 2019 for the
purposes of the assessments.
5.3.25. Major plant equipment (abnormal loads) including, for example parts of the boiler
and steelwork associated with the turbines, will be delivered to the Site via routes
identified in Chapter 10: Traffic and Transport. It is not possible at this stage to
identify the exact number and size of such loads, as these will be dependent on
the supplier of the plant, which is yet to be determined. Typically no more than
20-30 abnormal deliveries are required for a project of this nature. Such loads will
be identified in advance to the local authorities, and suitable routes and delivery
times agreed to minimise any potential disruption. It is not envisaged that any
deliveries will require any modifications to public roads and all deliveries will
comply with UK road regulations.
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Traffic Management
5.3.26. Estimated numbers of construction related vehicle journeys for the 37 month
construction period have been calculated based on volumes of estimates
construction material. A full impact assessment of the construction vehicle
movements on the surrounding road network is presented within Chapter 10:
Traffic and Transport.
5.3.27. Unapproved parking on the public roads will not be allowed and the site labour
force will be encouraged to use public transport. Any local traffic management
measures for site access will be agreed in advance of site works commencing
with SGC and BCC.
5.3.28. Primary access and egress during enabling works and construction will be via the
northwest perimeter of the CCR Site, connecting to the proposed new Spine
Access Road (see Figure 5-2, Volume III of the PEI Report), which Severnside
Distribution Land Ltd intends to construct under the extant 1957/58 consent.
5.3.29. Additional vehicular access will be available from the south along Ableton
Lane/Minor’s Lane, as well as through the eastern perimeter of the CCR Site
from an existing roundabout that will connect to the new spine access road
(Figure 5-2, Volume III of the PEI Report).
5.3.30. A secure construction compound will be developed in advance of site works. This
would include site welfare for operatives. Pedestrian, site and traffic management
plans will be drafted and clear routes established so that vehicle routes within the
DCO Site are clear.
5.3.31. It is anticipated that the construction of the Proposed Development would lead to
up to a maximum of 40 HGV deliveries (80 movements) per day during peak
construction.
Piling and Foundations
5.3.32. Certain areas within the Proposed Development Site are expected to require
below ground foundations and piling.
5.3.33. The infrastructure that is likely to require below ground foundations (and their
depth) is, as follows:
• Transformers (1000mm);
• Turbine and HRSG (2000-2500mm);
• Cooling Water Pumping Pits (3000-4000mm) and Pipework (2000mm);
and
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• Water tanks (1000mm)
5.3.34. Where piling is required, Continuous Flight Auger (CFA) / bored piling will be
implemented, which generates less noise than other types of piling (such as
impact or vibro-piling). CFA piling comprises drilling prefabricated piles into the
ground and pumping in concrete as the drill bit is removed.
5.3.35. Groups of piles will be connected by a pile cap (a large concrete block into which
the heads of the piles are embedded) to distribute loads which are larger than
one pile can bear.
Cooling Water Pipeline
5.3.36. As part of the Associated Development Infrastructure a new cooling water supply
pipeline will need to be installed for the Proposed Development Site. Ultimately,
water will be supplied from and returned to the Bristol WWTW, although the
supply and return pipelines will be routed via the existing Seabank 1 & 2 facilities.
5.3.37. A feasibility assessment was carried out to determine the preferred route,
configuration and diameter of the supply and return pipelines. It is currently
anticipated that as part of the associated infrastructure a new single 800mm
diameter pipeline will be required between Seabank 3 and the Bristol WWTW.
This pipeline will follow the route of the existing supply and return water pipeline
shown on Figure 1-2 (Volume III of this PEI Report). There will also be new
cooling water supply and return lines installed to connect the Proposed
Development to Seabank 1 & 2. It is anticipated that these will run around the
inside perimeter of the existing site.
5.3.38. The following information outlines the likely construction methods for the cooling
water pipeline, although Wessex Water will be undertaking the detailed design
study and installation of the proposed pipelines.
Trench Excavation
5.3.39. Trenching techniques will be used to install the new cooling water supply pipeline
underground to a depth of approximately 2 - 4m. The cooling water pipeline will
be laid within a the proposed cooling water pipeline corridor within the Other DCO
Land; an approximate 10m standoff distance from the existing Wessex Water
pipelines is required.
5.3.40. Figure 5-3 (Volume III of this PEI Report) illustrates the trenching methods likely
to be used.
5.3.41. The width of trenches will depend upon the location of the stretch of excavation.
For a length through fields the trenches would be between approximately 3m and
5m. For excavation in roads, the trenches would be sheeted (a vertical cut each
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side of the trench with support from steel sheets) to allow a trench width of 1-
1.5m.
5.3.42. A construction corridor of 20m will be established within the Other DCO Land to
allow areas for soil piles, laydown, and vehicle access.
5.3.43. Excavated materials will be stored adjacent to the trench to enable it to be used
for restoration of the site following the laying of the pipeline.
Lowering and Laying
5.3.44. Prior to lowering-in, the trench will be prepared to accept the pipe. Surface rocks
or debris that could damage the pipe coating will be removed from the trench.
Suitable selected material, imported fill or packers will be carefully placed in the
trench bottom prior to the pipe laying process. The excavated pipeline trench will
be checked to ensure that the pipe will be laid with the correct cover and that the
pipe will not be damaged during installation.
Special Crossings
Streams and Ditches
5.3.45. Crossing of streams, ditches and rivers will either be by boring/drilling under the
watercourse or by open trenching (using either a wet or dry technique) if
necessary. The choice of method will depend upon several considerations
including the size, nature and location of the watercourse.
5.3.46. For the dry technique upstream and downstream temporary dams of steel sheet
piling or “sandbags” will be formed and the flow piped or pumped around the
temporary obstruction formed by the coffer dams. The pipe trench will then be
excavated in the dry and the pipeline constructed in the normal way. Afterwards
the temporary dams and appurtenant work will be removed and the bed and
banks reinstated to their original condition.
Road Crossings
5.3.47. There are expected to be around six crossings at the roads listed below:
• Severn Road
• Chittening Road
• Washingpool Lane
• Mooreend Farm Avenue
• Poplar Way E; and
• Lawrence Western Road.
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5.3.48. At road crossings the cooling water pipeline will be sheet trenched to a depth of
1m using sheet trenching to minimise the width of the trench, as described
above.
Railway Crossing
5.3.49. The cooling water pipeline between the Bristol WWTW and Seabank 1 & 2
crosses underneath an existing railway track at grid reference 353071, 180910
(x,y) and will need to be bored or drilled sing HDD under the embankment. After
consultation with Network Rail, it was established that monitoring would be
undertaken within 3m (at a 45 degree angle) either side of the track, before,
during (drilling only) and after works have been completed.
5.3.50. A steel pipeline sleeve is also required with 10m clearance from the crossing
either side of the track to safeguard the pipeline from water damage. With the
sleeve the pipeline will be approximately 900mm in diameter and must be
trenched at least 4.3m below the sleeper.
Utilities
5.3.51. The cooling water pipeline also crosses a number of utility services and pipelines.
A detailed utilities search will be undertaken before construction.
5.3.52. Five of these crossings are with Government Pipeline and Storage System
(GPSS) pipelines. Details of each of these crossings are as follows:
• Crossings 1 to 3 are located on the Hallen to Avonmouth (HA) line (ST
530 858 0928):
o HA1 is located on the north side of the railway at a measured depth
of 1.5-1.8m depth (varies) with an estimated 12-20” diameter;
o HA2 is located beneath GPPS(1) at an estimated depth of 2m; and
o HA3 is an abandoned pipeline located on the south side of the
railway, approximately 6-10” diameter.
• Crossings 4 and 5 are located on the Chittening to Berwick Wood (CB)
line (ST 534 6581828). CB4 and CB5 are both approximately 1.8m in
depth and run parallel to one another.
5.3.53. The cooling water pipeline would need to be a minimum of 600mm beneath the
base of each of the above pipelines, so an estimated minimum depth of 2.9-3.2m
is required at these crossings (taking into account the pipeline depth and pipe). It
is intended that the new pipeline will be installed at approximately 4m depth at
these locations.
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Bedding and Backfill
5.3.54. The pipelines will be laid on granular bedding material, covered in selected fill,
and then excavated backfill. The exact design/ structure of the bedding and
backfill will be determined by the current use (i.e. highway, sewers etc.) and soil
type. Backfilling will occur in reverse sequence of removal to help ensure layers
are maintained where possible.
5.3.55. Where possible and subject to soil quality tests, excess spoil that is not required
for backfilling the trench (because the space is filled by the pipeline) will be used
as part of the land raising on the Proposed Development Site. This should avoid
the need for offsite disposal of any excess material.
Leak Testing
5.3.56. There will then be a requirement to hydrostatically test the pipeline. The pipeline
will be filled with water via the Bristol WWTW and pressure tested for leaks.
5.3.57. A pressurised pump and mobile test cabin will be sited at safe proximity from the
pipeline. Test instrumentation and the pressurising pump will be connected up to
the test head. The pipeline will be brought up to the test pressure and then
maintained for an estimated 24 hours. On acceptance of the test the pressure will
be reduced in a safe and controlled manner down to the static head pressure for
dewatering.
Clean Up and Restoration
5.3.58. Following completion of testing, reinstatement of the construction corridor will be
undertaken by a specialist crew which will aim to return the ground to its original
condition. Residual construction debris, including all temporary fencing, will be
removed from all construction sites.
5.3.59. Topsoil will be replaced to return the depth over the working width to the original
levels. The reinstatement of cultivated or grassed areas will only be carried out
when weather and ground conditions are suitable.
5.3.60. Disturbed areas in natural habitat areas will be seeded with a mixture of native
plant species to facilitate re-vegetation. Hedgerows disturbed by construction
activity will be re-instated, but tree planting will not be undertaken along the
pipeline route within woodland areas. Due to the possible interference of roots
with the integrity of the pipeline, there are restrictions on tree species and
planting distances from the pipeline.
5.3.61. These aspects are discussed further in Chapter 16: Ecology and Chapter 17:
Landscape and Visual Assessment.
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Electrical Connection
5.3.62. Another part of the Associated Infrastructure is the electrical connection between
the Proposed Development and Seabank Substation. It is envisaged that the
cabling would be above ground, on an aerial cable bridge rack, however the
option for HDD beneath the Seabank 1 & 2 infrastructure remains a possibility.
The following two sections outline both of these methods.
5.3.63. Where electrical connections are installed above ground, they will be placed in a
rack inside a waterproof casing to protect against water damage and is therefore
not vulnerable to flood risk.
Cable Racks
5.3.64. The aerial cable bridge racks will be approximately 600mm wide and a height of
up to 3m, with 1.2m wide supports every 5-10m. Cable bridges may be needed to
lift the cable rack over equipment within the Seabank 1 & 2 site, which may lead
to the height increasing at specific locations.
5.3.65. The supports will be installed with approximately 1m deep foundations with a
construction corridor of approximately 20m. Figure 5-4, Volume III of this PEI
Report illustrates a typical electrical cable rack.
Horizontal Directional Drilling (HDD)
5.3.66. If required, HDD would utilise a drilling technique to lay the cable underneath
Seabank 1 & 2 site with minimal disturbance. The normal course taken by the
drilling operation is described in the following:
1. Planning, preliminary survey
2. Selecting the drilling units and drilling tools
3. Pilot bore and detection
4. Backreaming(s) or upsizing bore(s); and
5. Pulling in the pipe.
5.3.67. Figure 5-5 (Volume III of this PEI Report) illustrates a typical example of HDD.
Construction Method Statement (CMS)
5.3.68. The Principal Contractor will be appointed by the developer to develop and
implement a Construction Method Statement (CMS) through which mitigation and
compliance with The Construction (Design and Management) Regulations 2007
(Ref. 5-1) will be achieved.
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5.3.69. The CMS will outline the different procedures to be undertaken in order to
complete the various works. Individual trade contracts will incorporate
requirements for environmental control, based on good working practice, such as
careful programming, resource conservation, adhering to health and safety
regulations and quality procedures. In this way those involved with the
construction phase, including trade contractors and site management, will be
committed to adopting the agreed best practice and environmentally sound
methods.
5.3.70. The CMS will be prepared in consultation with SGC and BCC at least 28 days
prior to the commencement of on-site works.
5.3.71. The CMS will include the following items:
• The updated construction programme;
• A broad plan of the construction works, highlighting the various stages
and their context within the project, including a full schedule of materials
and manpower resources, as well as plant and equipment schedules;
• Detailed site layout arrangements (including requirements for temporary
works), plans for storage, accommodation, vehicular movements,
delivery and access;
• Prohibited or restricted operations (locations, hours, etc.);
• Details of operations that are likely to result in disturbance, with an
indication of the expected duration of each phase with key dates,
including a procedure for prior notification of SBC and BCC and relevant
statutory and non-statutory (including neighbours) parties so that local
arrangements can be agreed;
• Details of utilities diversion;
• Site working hours;
• A procedure to ensure communication is maintained with SBC and BCC
and the local community to provide information on any operations likely
to cause disturbance (e.g. through meetings and newsletters);
• Provisions for affected parties to register complaints and the procedures
for responding to complaints;
• Provisions for reporting to the Applicant and SBC and BCC;
• Details of access and egress and proposed routes for HGVs; and
• Details of construction traffic (including parking and access
requirements) and changes to access and temporary road or footpath
closure (if required).
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5.3.72. The CMS will be produced following receipt of the DCO (for example, as part a
Requirement attached to the DCO) and will identify all the procedures to be
adhered to throughout construction.
5.3.73. Individual trade contracts will incorporate environmental control, health and safety
regulations, and current guidance. This will ensure that construction activities are
sustainable and that all contractors involved with the enabling, preparation and
construction stages are committed to agreed best practice and meet all relevant
environmental legislation including: Control of Pollution Act 1974 (COPA) (Ref. 5-
3), Environment Act 1995 (Ref. 5-4), Hazardous Waste Regulations 2005 (Ref. 5-
5), and the Duty of Care Regulations 1991) (Ref. 5-6). Records will be kept and
updated regularly ensuring that all waste transferred or disposed of has been
correctly processed with evidence of signed Waste Transfer Notes (WTNs) that
will be kept on-site for inspection whenever requested. Furthermore all enabling,
preparation and construction works will adhere to the CDM Regulations (2007)
(Ref. 5-1).
Construction Environmental Management Plan (CEMP)
5.3.74. The commitments made within the CMS and ES will be incorporated into a
CEMP, which will include roles and responsibilities, detail on control measures
and activities to be undertaken to minimise environmental effects, and monitoring
and record-keeping requirements. The CEMP will describe the specific mitigation
measures to be followed to reduce nuisance effects from:
• Use of land for temporary laydown areas, accommodation, etc. It is
currently anticipated that the land to the east of the scheme reserved for
CCS will be used for laydown areas during construction;
• Enabling, preparation and construction traffic (including parking and
access requirements);
• Changes to access and temporary road or footpath closure (if required);
• Noise and vibration;
• Utilities diversion;
• Dust generation;
• Soil removal; and
• Waste generation.
5.3.75. Typical mitigation measures included in the CEMP will include the following:
• Restricted working hours and a procedure for consenting exceptions;
• A Commissioning Plan; and
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May 2014 Page 5-19
• A Risk Management Plan.
5.3.76. A commitment will be made to periodically review the CEMP and undertake
regular environmental audits of its implementation during the construction phase
of the Proposed Development and associated infrastructure.
5.3.77. A framework for the CEMP which will be developed following receipt of the DCO
is provided in Technical Appendix C, Volume II of this PE Report.
Waste
5.3.78. Small amounts of waste will be generated during the construction programme.
The main sources of waste within the construction process are anticipated to
include:
• Packaging – plastics, pallets, expanded foams etc;
• Waste materials generated from inaccurate ordering, poor usage, badly
stored materials, poor handling, spillage etc; and
• Liquid wastes, other than surface water run-off and foul drainage, such
as waste oils and chemicals.
5.3.79. Any waste will be carefully managed and cleared to prevent nuisances such as
litter, dust, odour and pests, and to maintain a “clean” working and site
environment, for the benefit of all parties.
5.3.80. Contaminants found within the excavated material will be evaluated through site-
specific chemical test data, including Waste Acceptance Criteria (WAC) and
disposed of in accordance with relevant legislation.
5.3.81. During the construction phase, requirements for the management of waste will be
communicated to all contractors and sub-contractors to ensure that waste is
managed in accordance with the waste hierarchy and relevant statutory controls.
These measures will be controlled through the CEMP in consultation with the
relevant authorities.
5.3.82. A Site Waste Management Plan will be produced for the Proposed Development
post consent and prior to commencement of site works.
5.4. Operation
5.4.1. The operation of the Proposed Development is discussed in Chapter 4: Project
Description.
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5.5. Decommissioning
5.5.1. It is envisaged that the plant will have a design life of at least 30 years, although
the operational life may be extended. After this time on-going operation will be
reviewed and if it is not appropriate to continue operation the site will be
decommissioned.
5.5.2. At the end of its operating life, the plant and all equipment will be shutdown and
removed from the Proposed Development Site. Prior to removing the plant and
equipment, all residues and operating chemicals would be cleaned out from the
plant and disposed of in an appropriate manner.
5.5.3. The fuel storage areas will be sealed to contain any leaks or spillages. It is
therefore highly unlikely that the Proposed Development will create any new
areas of ground contamination. Once the plant and equipment have been
removed to ground level, it is expected that the hardstanding and sealed
concrete areas will be left in place. Any areas of the plant which are below
ground level will be backfilled to ground level to leave a levelled area.
5.5.4. The decommissioning and demolition of the Proposed Development would be
considered at the detailed design stage as required by the Construction Design
and Management (CDM) Regulations.
5.5.5. A Decommissioning Plan will be produced and agreed with the EA as part of the
environmental permitting process.
5.5.6. The following measures will be employed in the Design of Works to manage
(including elimination) SHE risks decommissioning stage. Particular attention will
be given to avoid use of deleterious materials and the contamination of ground
due to material/chemical storages and plant operations.
Avoidance of Deleterious Materials
5.5.7. The Prohibited Materials will not be allowed within the Works, including all
elements of Plant.
5.5.8. Where a material is recognised as posing a risk to the health of either or both
personnel and environment, however is not a Prohibited Material, it’s use in the
Works shall be subject to detailed risk assessment.
5.5.9. The following materials are prohibited and the Contractor will be instructed to
avoid their use within the Works;
• Asbestos or asbestos-containing materials;
• Naturally occurring aggregates for use in reinforced concrete which do
not comply with the relevant standards;
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May 2014 Page 5-21
• Cast iron piping materials for any oil service;
• PCBs;
• CFC’s or other ozone depleting substances, except in applications where
their use is accepted and cannot be avoided, subject to Project Manager
acceptance;
• Carcinogenic materials;
• Materials known in the construction industry at the time of use to be
deleterious to health or the environment when used or incorporated in
such Work;
• Material which is known to or is reasonable believed to cause failures in
buildings;
• Material which is accepted as being or is believed to be deleterious via:
a. becoming deleterious when used in a particular situation or in
combination with another material(s);
b. becoming deleterious without a level of maintenance higher than that
expected in a plant of comparable type; and
c. being damaged by or causing damage to any structure in which it is
incorporated or affixed.
• Tropical hardwood which is not obtained from a source accredited in the
Good Wood Guide published by Friends of the Earth.
• Materials which are not in accordance with recommendations within a
booklet entitled “Good Practice in the Selection of Construction
Materials” written by Ove Arup & Partners and sponsored by the British
Property Federation & British Council for Offices, any Statutory
requirements, British Standards, Codes of Practice or good building
practice.”
Above the Ground Storages/silos for Chemical Storages
5.5.10. All chemicals including fuel for diesel generators will be stored in above the
ground silos. The silos will be required to comply with the relevant British
Standards and good industry practice. All Silos will be provided with the
containment measures as per HSE guidelines. All additional measures (other
than robust design), such as containment, emergency response, arrangements
for offsite transport and treatment/disposal, will be in place to avoid any ground
contamination form chemicals.
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Segregation of Dirty/Clean Water
5.5.11. Run-off or spillages from designated 'dirty' areas and process water discharges
will be segregated from clean works area and surface water runoff and be
separately contained for disposal offsite via road tanker. Contaminated water
containment systems will accommodate all additional loading from fire water
systems. All contaminated water resulting from normal, abnormal or emergency
Plant conditions shall be contained and either reused in the plant or transported
off site for treatment or safe disposal.
5.6. References
Ref. 5-1 HMSO (2007); The Construction (Design and Management) Regulations
Ref. 5-2 DECC (2009) Carbon Capture Readiness (CCR) A guidance note for Section 36 Electricity Act 1989 consent applications
Ref. 5-3 HMSO (1974); Control of Pollution Act (amended 1989)
Ref. 5-4 HMSO (1995); The Environment Act
Ref. 5-5 HMSO (2005); Hazardous Waste (England and Wales) Regulations
Ref. 5-6 HMSO (1991);The Environmental Protection (Duty of Care) Regulations
Seabank 3 PEI Report – Chapter 6 Project Need and Alternatives
May 2014 Page 6-1
6. Project Need and Alternatives
6.1. The Need for the Proposed Development
6.1.1. The Energy White Paper ‘Meeting the Energy Challenge’, published in 2007 by
the Department for Trade and Industry, formed the basis of the Energy Act 2008
(Ref. 6-1) and sets out the Government’s plans for tackling climate change by
reducing carbon emissions whilst ensuring the availability of secure, clean,
affordable energy.
6.1.2. The White Paper and the Overarching NPS for Energy (EN-1) (Ref. 6-2) both
emphasise the importance of a diverse mix of energy generating technologies,
including renewables, nuclear and fossil fuels, to avoid over-dependence on a
single fuel type and thereby ensure security of supply.
6.1.3. Changes to the current mix of energy generating plant will occur as a large
number of existing oil, coal and nuclear power stations close over the next 10-15
years due to the requirements of the European Large Combustion Plant Directive
and/or as plants reach the end of their operational lives. Projections quoted in the
Energy NPS indicate 22 gigawatts (GW) of electricity generating capacity will
close over this period. This creates a significant need for new major energy
infrastructure.
6.1.4. The long lead-in for new nuclear power stations means that new fossil fuel and
renewable generating capacity will also need to be progressed to meet demand.
6.1.5. Renewable energy is important to achieve the UK’s targets for reductions in
carbon emissions but the Energy NPS also emphasises the on-going requirement
for fossil fuel power stations as they offer more flexibility in response to changes
in energy demand compared to many renewable energy technologies.
6.1.6. Gas-fired generation contributes to the objective of reducing carbon dioxide
(CO2) emissions, as generating electricity from natural gas is more efficient than
other fossil fuels such as coal, resulting in significantly lower CO2 emissions per
MW compared to alternative fossil fuel power stations.
6.1.7. The recent draft Electricity Market Reform (EMR) Delivery Plan by the DECC
(Ref. 6-3) also outlines a greater need for flexible capacity in gas-fired generation
to ensure supply can meet demand at all times. DECC indicates an expected
requirement for up to 23GW of peaking plant by 2030 to support the provision of
renewable power generation such as wind power.
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6.2. Alternative Sites
6.2.1. The Applicant continuously considers potential sites for new power generation
development. In addition to the Proposed Development Site at Severnside, the
Applicant has considered a number of other sites in the UK for new gas fired
generating stations, several of which may lead to further DCO Applications.
6.2.2. A range of factors are considered in the selection and prioritisation of generating
station development sites, many of which relate to the commercial viability of
development. These include:
• Availability and suitability of sufficient land (not only for the power
generation technology but also for potential future CCS technology and
laydown areas for construction);
• Site sensitivity in terms of proximity to sensitive receptors such as
residential areas or designated ecological receptors;
• Site constraints including topography and ground conditions;
• Distance to electricity grid connection and gas supply connection and
location on the grid network, along with the cost of connection; and
• Accessibility.
6.2.3. The Proposed Development Site was selected primarily because of its proximity
to Seabank 1 & 2, which the Applicant already has a stake in, and the opportunity
this brings to utilise the existing gas, water and electricity infrastructure, avoiding
the need for significant additional infrastructure beyond that already planned. The
ability to avoid having to construct a cross country gas pipeline and overhead
electricity lines represents a significant cost saving, minimisation of
environmental effects, and a noticeable reduction in project risk.
6.2.4. The Proposed Development Site also has excellent road links with easy
accessibility to the M49, M5 and M4, as well as the potential access to a pool of
existing skilled labour at Seabank 1 & 2 for operations and maintenance should
the two sites ever be merged.
6.2.5. The Proposed Development Site is part of the Severnside area, which is
allocated by the SGC Core Strategy (Ref. 6-4) for employment uses based on
extensive opportunities for storage and distribution development. Its industrial
setting also means there are relatively few sensitive receptors in the immediate
surrounds, with the nearest residential dwellings comprising a few scattered farm
dwellings approximately 1.1km southeast of the Proposed Development Site.
6.2.6. It is important to note the Applicant has already secured a 1,200MW grid
connection agreement with National Grid from 2019 for the Proposed
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Development and is currently negotiating an extension to this, which would
increase it to 1,400MWe.
6.2.7. Further justification for the need for the Proposed Development and choice of site
is presented in the Planning Statement, which has been submitted as a
supporting document to the DCO Application.
Do Nothing Alternative
6.2.8. It is considered that the ‘Do Nothing’ scenario is not appropriate given the
established need for new energy generation in the UK (outlined in Overarching
NPS for Energy EN-1, Ref. 6-2). Furthermore the allocation of the Severnside
area for distribution and other extensive employment uses, including energy
generation, in the SGC Core Strategy underlines the importance of providing new
generating capacity at the Proposed Development Site. A key disadvantage of
the ‘Do Nothing’ scenario would be the lack of additional investment in the local
economy and failure to contribute to the energy need outlined above.
6.3. Consideration of Alternative Locations within the Selected Site
6.3.1. There are relatively few options available in relation to the specific location of
plant given the constraining size and shape of the Proposed Development Site.
The preferred location of the Generating Station Site, adopted for the concept
design to date and as assessed in this PEI Report, is in the western part of the
Proposed Development Site, adjacent to the Seabank 1 & 2 site.
6.3.2. The principal reason for locating the Generating Station Site and its components
adjacent to Seabank 1 & 2 is that it enables the electrical cables and cooling
water pipeline to be routed through the existing generating station, the option of
an access point connecting the two stations, and for the two sites to be operated
as a common station should Seabank Power Ltd (current operators of Seabank 1
& 2) choose to invest in the Proposed Development at any point in the future.
There is also no immediate requirement to divert overhead lines, which are
present on the CCR Site.
6.3.3. In terms of plant layout, as a Main Contractor has not yet been selected for the
construction of the Proposed Development, the concept design has been
developed to allow for a range of technologies and plant layouts. The objective of
this is to ensure a number of potential contractors could tender for and ultimately
construct the Proposed Development utilising their preferred technology and
plant layout. Maximum and minimum parameters have therefore been defined
(see Chapter 4: Project Description) and assessed within this PEI Report utilising
a ‘Rochdale Envelope’ approach (see Chapter 2: The DCO and EIA Process).
Information received during the preliminary design work and from other CCGT
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plants constructed elsewhere in the UK or overseas, has been utilised to
establish the maximum and minimum parameters required for each element of
the plant.
6.3.4. The development parcels have been ‘fixed’ in terms of location for the purposes
of this PEI Report, with the buildings retaining more ‘flexibility’ in their layout
within the ‘Rochdale Envelope’.
6.4. Consideration of Alternative Layouts within the Selected Site
6.4.1. Prior to publishing the Scoping Report the Applicant investigated various options
in terms of the design layout and installed capacity of the Proposed
Development. The feasibility and design options study considered the following
options for the Proposed Development Site:
• A 400MW CCGT generating station on a minimum plot area of 7ha;
• A 800-850MW CCGT generating station on a site of 14-18ha; and
• Up to a 1,400MW CCGT power station on an area of around 19ha (the
chosen scheme, albeit on a larger footprint to include peaking plant and
an area designated for CCS).
6.4.2. The 400MW and 800-850MW alternatives were abandoned in favour of the larger
electricity output achieved by the chosen scheme in order to maximise the
generating potential of the Proposed Development Site.
6.4.3. The subsequent layout of the chosen scheme was influenced by the dimensions
of the key elements of plant and equipment that need to be housed within the
main buildings and by the engineering requirements needed for the CCGT Plant
to operate in the most efficient manner.
6.4.4. The following considerations were taken into account during the layout design:
• Utilities and services corridor: The inclusion of a services corridor
along the southern boundary of the Proposed Development Site,
following the existing line of Feeder 14 gas pipeline, to accommodate
existing, relocated, and future pipelines, within a reserved area free from
buildings and structures. If CCS is ever to be implemented then the
services corridor would also provide a route for power plant
interconnecting ductwork.
• Cooling system: This is located at the western end of the Generating
Station Site, mimicking the general visual massing of Seabank 1 & 2 with
cooling water system in the west of the existing station. This is also
deemed the optimum site location when considering prevailing wind
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direction (west to southwest) to prevent screening by the higher
structures onsite, thus it will aid the cooling effect in the cooling water
system.
• Switchyard: The 400kV switchyard has been located near to southwest
boundary, close to the exit point to Seabank 1 & 2, in line with the cable
route to the Seabank 400kV substation.
• Peaking Plant: The peaking plant units were originally located closer to
the main boilers and stacks, however preliminary air dispersion modelling
demonstrated that the stack heights and air quality impacts could be
reduced slightly by moving these units further east within the Generating
Station Site, geographically separating them from the HRSG building.
6.4.5. In addition to engineering requirements, environmental effects have been
considered throughout the design process. These include the orientation of the
power block buildings to screen the stacks, and keeping a distance from public
roads to reduce the visual impact. Space has also been incorporated for
landscaping, water attenuation ponds, and ecological habitat mitigation in the
latest design.
6.4.6. Figures 6-1 to 6-3 (Volume III of this PEI Report) illustrate some of the key
changes to the Proposed Development throughout the project evolution, based
on the single shaft layout:
• Figure 6-1 (Volume III of this PEI Report) illustrates the layout of the
Proposed Development for the initial concept produced in April 2012,
which comprised two 600MW CCGT units. It shows the turbine and
HRSG buildings at the westernmost end of the Site, with the cooling
water system to the east. No peaking plant is included at this stage of the
design.
• Figure 6-2 (Volume III of this PEI Report) illustrates an interim layout in
March 2013. Five options were considered at this stage; some options
had the cooling water system located west of the turbine and HRSG
buildings, whilst others retained the cooling water system to the east of
these buildings. They also tested different orientations for the turbine and
HRSG buildings. The option that is illustrated in Figure 6-2 (Volume III)
shows the cooling water system now located in the west of the Site and
incorporates peaking plant immediately east of the turbine and HRSG
buildings.
• Figure 6-3 (Volume III of this PEI Report) presents an amended layout in
August 2013. The cooling water system is still shown in the western side
of the Site, aligned slightly differently but still northwest to southeast. The
turbine and HRSG buildings have been expanded slightly to incorporate
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May 2014 Page 6-6
the maximum design parameter from a range of potential Contractors
and achieve up to 1,400MW. The peaking plant has been moved away
from the turbine and HRSG buildings to the eastern part of the
Generating Station Site; preliminary air quality modelling showed that the
peaking plant stack heights would have had to be similar in height to the
main stacks if they were retained in their previous location.
• Figure 4-2 and Figure 4-3 (Volume III of this PEI Report) illustrate the
final layout utilised for this PEI Report. The cooling water systems have
been reoriented, so they are now aligned southwest to northeast. This
enabled the other main structures onsite to move west slightly away from
the narrowest part of the Site, which in turn allowed a new landscaping
area for trees and vegetation between the northern facades of these
buildings and the 8m easement along the Red Rhine. This also removed
the need for the retaining wall along this 8m easement shown on earlier
iterations, and provides some vegetation screening for views from users
of the Access Spine Road.
The peaking plant is now shown as enclosed within a building, for design
consistency with the other buildings onsite (although depending on the
technology selected there is the possibility that these may not require to
be enclosed, as discussed later in this chapter). They have also been
moved slightly, to avoid a clearance area beneath the 400kV OHL.
There is a new area of landscaping between the Generating Station Site
and the CCR Site, to breakup long distance views from the east, and
which is shown to include a rainfall runoff attenuation pond. And finally,
the proposed PROW, which previously dissected the Generation Station
Site and CCR Site, is now shown as being routed along the length of the
CCR Site, around the southern boundary of the Proposed Development
Site to the existing roundabout that currently lies immediately to the east
of the Site.
6.4.7. In order to ensure the CCR Site was of sufficient size, some preliminary layouts
show the CCS technology superimposed (although it was never intended that this
would form part of the DCO Application).
Stack and Building Heights
6.4.8. In order to allow for further project evolution and development, and to provide
sufficient flexibility in the final design, maximum dimensions are set out in
Chapter 4: Project Description. This approach enables the EIA to be undertaken
on the maximum or worst case basis, and provides the flexibility needed within
the DCO Application to enable a range of equipment supplier and Contractors to
be considered.
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6.4.9. The stack height has been informed by air dispersion modelling, technical
feasibility studies and the informal consultation process, and has been fixed at
90m above the finished ground level for the purposes of this PEI Report (the
equivalent of 98.5m AOD assuming the finished ground level is built to its
maximum 8.5m AOD, as discussed in Chapter 5: Enabling Works and
Construction). This is a reduction of 10m from the EIA Scoping Report, which
suggested the main stacks would be up to 100m above the finished ground level.
6.5. Alternative Technologies
6.5.1. Throughout the design process consideration has been made to alternative
technologies, design options and plant layout. These decisions have, where
relevant and possible, been informed by environmental appraisal work and the
design has evolved through a continuous process of environmental assessment
and design development.
6.5.2. Aspects where options have been considered and these are now ‘fixed’ include
the method of cooling, which is discussed further below.
6.5.3. There are also a number of aspects of the design where options remain
available. Some of these aspects will have a final option determined at the time of
the application, though others are likely to retain options within the final DCO
Application. The selection of specific options, along with any project evolution of
the concept design, will be informed, where appropriate by the EIA work, on-
going discussions with potential bidders for the construction of the plant and the
feedback received through the consultation process.
Cooling Units
6.5.4. A cooling system is required to enable the Proposed Development to condense
the steam used in the power generation process once it has been exhausted
through the steam turbine, and before it is returned to the boiler for re-use.
6.5.5. At the outset of the scheme, three types of cooling methods were available:
• Direct wet-cooling technology: This consists of high efficiency water-
cooled condensers. It requires the abstraction of large quantities of water
from an accessible water source and the discharge of warmer water back
into the water source after it has been used for cooling. This method of
cooling requires the construction of an intake and outfall structure within
an appropriate controlled water body, such as a main river or estuary.
The main advantage of this cooling method is that it uses a colder
cooling medium (river water as opposed to air) and avoids the electrical
consumption of the fans used in air cooled condensers, thereby
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improving the thermal efficiency of the fuel used. However, the
abstraction and discharge of water can only be undertaken in locations
and in a way that would not give rise to significant impacts on the water
body and the environment.
• Hybrid-cooling technology: This is essentially a combination of dry-
cooling and wet-cooling. Water must still be abstracted from a controlled
water source but by using a bank of low height cooling cells a smaller
volume of water needs to be abstracted than for direct water cooling, and
the temperature of the returned water is also lower. However, the use of
cooling cells can give rise to visible water plume emissions to air under
certain meteorological conditions and also results in a marginally lower
plant thermal efficiency than direct water cooling.
• Dry-cooling technology: This consists of a system of air-cooled
condenser fans situated in fan banks. The steam is condensed directly
by air in a heat exchanger (the air cooled condenser) and the
condensate is returned to the steam cycle in a closed loop. The air flow
is induced solely by mechanical draft from the fans. This cooling method
requires electrical energy to operate the fans, and therefore results in
reduced electrical output to the national transmission system. This
therefore increases fuel consumption and the emission of exhausts
gases for each megawatt of electricity produced, thereby reducing the
thermal efficiency of the system. However, the advantages of air cooled
condensers are that they require no cooling water abstraction, treatment
or discharge of cooling water and do not give rise to any visible plumes.
6.5.6. A feasibility assessment concluded that there are no fundamental reasons that
would technically prevent the adoption of direct sea water cooling for the
Proposed Development, and plant output would increase by approximately 1%. It
was however anticipated that there would be the potential for significant effects
on the environment, shipping and navigation, as well as substantial design and
construction challenges associated with extracting water from the Severn
Estuary, due to its high tidal range.
6.5.7. The full Best Available Techniques (BAT) justification will be presented with the
DCO Application. Preliminary discussions with the EA indicate that they concur
with the view that hybrid cooling water systems represent BAT for this installation,
due to a combination of technical and environmental challenges including the
effect on the ecologically sensitive marine environment that could arise from the
need to abstract and, in particular, discharge cooling water into the estuary.
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Grid Connection
6.5.8. There are a number of options available for a Grid Connection which are
currently being evaluated, as outlined in Chapter 4: Project Description, and this
work is likely to be on-going when the final DCO Application is submitted. This
includes the option of underground cabling, which will be installed using HDD
beneath the Seabank 1 & 2 generating station, or an above ground cable rack
routed through the Seabank 1 & 2 station. The option of overhead lines was
dismissed for the Proposed Development.
CCGT Configuration
6.5.9. Another area where the design has evolved since the submission of the Scoping
Report and the informal consultation is regarding the configuration of the
generating station, as detailed below.
6.5.10. A number of alternative layouts have been considered for the Generating Station
Site, mainly in response to engineering requirements as outlined above. The two
remaining options include a multi-shaft and single-shaft CCGT as illustrated in
Figure 4-2 and Figure 4-3, Volume III of this PEI.
6.5.11. The single-shaft design provides more flexibility than if the gas and steam
turbines had their own generators, although the multi-shaft design enables two or
more gas turbines to operate in conjunction with a single steam turbine, which
can be more economical than having a separate steam turbine for each single
shaft unit.
6.5.12. At this stage, the configuration design will be left open to allow for flexibility in the
DCO Application. The single-shaft design is generally considered to be the ‘worst
case’ for the purposes of the technical assessments, as this layout has a slightly
larger footprint than the multi-shaft option.
Fast Response Generator / Peaking Plant
6.5.13. The Proposed Development includes the option of a peaking plant / fast
response generator up to 240MWe net, as set out in Chapter 4: Project
Description.
6.5.14. Different options were considered for the peaking plant including gas turbines
and reciprocating engines operating in open cycle mode as this offers the ability
to respond to changes in demand quicker than units operating in combined cycle.
6.5.15. Reciprocating engines generally have a smaller electrical output, typically up to
18MW capacity. Operating a number of these engines in concert provides greater
flexibility to respond to grid demand, however using larger gas turbines could
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provide the same capability with fewer moving parts. The optimum configuration
has not yet been determined and may consist of a combination of these
technologies.
6.5.16. Preliminary air dispersion modelling demonstrated that the effect of having 13
reciprocating engines up to 240MWe was similar (within 1% of one another) to
two OCGTs up to 240MWe, provided the emissions associated with the former
are ducted together into two separate stacks (see Chapter 11: Air Quality). It was
decided therefore to retain the flexibility in the DCO Application for either
technology, with the footprint of the peaking plant units enlarged slightly so that it
can incorporate either option.
6.5.17. At this stage of the project it has not been determined whether or not the peaking
plant will be enclosed in a building. Reciprocating engines require an enclosure
and would therefore be covered by a building; this represents the maximum
design parameters because it requires a noticeably larger and taller structure to
house these machines. OCGTs are inherently enclosed and protected from the
weather and do not require an additional enclosure or building. Given that this
would substantially reduce the footprint and height of the peaking plant, it has not
been ruled out at this PEI stage.
6.5.18. The predicted effect associated with the atmospheric emissions is presented in
Chapter 11: Air Quality of this PEI Report.
Solar PV
6.5.19. Solar PV does not form part of the Proposed Development, however it was
considered as a means to supplement the energy requirements for the DCO Site
activities.
6.5.20. Roof mounted solar panels on the buildings within the Proposed Development
were discounted due to economic reasons; greater carbon savings can be
achieved by diverting the money on improving plant efficiency rather than
installing solar PV. This would negate the purpose of installing solar PV on the
site.
6.5.21. Ground based solar PV is still being investigated for the CCR Site, but does not
form part of the Proposed Development. The Applicant is committed to exploring
opportunities for this technology with local solar PV installation companies, which
if successful would be subject to a separate consenting process with SGC. The
CCR Site offers numerous benefits for solar generating facilities, such as the
existing electrical infrastructure being in place.
6.5.22. Any development on the CCR Site would need to avoid enhancing the ecological
value of this land (in accordance with NPS for Energy EN-1) (Ref. 6-2) to allow
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the CCR Site to be made available should the Proposed Development be
required to install carbon capture technology. Carbon Capture would require a
separate DCO Application however, and therefore an investor would have
sufficient notice to decommission any development and vacate this land.
6.6. Associated Infrastructure
6.6.1. The scoping report (Ref. 6-5) presented a large indicative study corridor for a new
pipeline to supply cooling water and the electrical connection to Seabank
Substation. This corridor was approximately 1km wide, stretching from the M49 in
the east to Chittening Road.
6.6.2. Through the design process, identification of sensitive locations, and consultation
with BCC, it was decided that the route of the new cooling water pipeline should
follow the route of the existing two pipelines that currently supply/return cooling
water to Seabank 1 & 2. Most importantly, this would avoid sensitive ecological
receptors, namely a SNIC to the east of the cooling water pipeline.
6.6.3. The electrical connection corridor was also necessarily broad at the Scoping
stage, but is now restricted wholly within the Seabank 1 & 2 site, therefore
minimising any environmental impacts to undeveloped land.
6.7. Conclusions
6.7.1. Through analysis of site context, the Applicant’s development brief and
environmental considerations, a number of alternative designs have been
considered. The design was an iterative process whereby analysis of alternatives
was interpreted and proposals were made in order to address the concerns of
consultees and mitigate potentially adverse effects. Whilst the site strategy has
remained in line with the development brief, the detailed design has evolved
throughout the design and consultation process.
6.7.2. This process ultimately led to the present use, scale and form of the Proposed
Development, which is described further in Chapter 4: Project Description.
6.8. References
Ref. 6-1 HMSO (2008); Energy Act
Ref. 6-2 DECC (2011) Overarching NPS for Energy (EN-1)
Ref. 6-3 DECC (2013) Electricity Market Reform (EMR) Draft Delivery Plan
Ref. 6-4 South Gloucestershire Council (2013) Core Strategy
Ref. 6-5 URS (2012) Seabank 3 Scoping Report
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7. Assessment Methodology
7.1. Introduction
7.1.1. This chapter of the PEI Report sets out the overall approach to the preparation of
the EIA and in particular the statutory requirements as outlined in the EIA
Regulations.
7.2. EIA Methodology
7.2.1. The EIA process as reported in this PEI Report has been prepared taking into
account or having had regard to:
• Consultation with statutory and non-statutory consultees to understand
the environmental and socio-economic issues concerning the
development of the DCO Site, in particular any development constraints
and opportunities;
• EIA scoping to agree and determine the subject matter of the EIA and to
identify potentially significant issues;
• Local, regional and national planning policies, guidelines and legislation
relevant to the EIA;
• Establishment and definition of the baseline conditions;
• Effects significance criteria, using published criteria where available;
• Identification of sensitive receptors;
• Design review and assessment of alternatives;
• Review of secondary information, previous environmental studies, and
publicly-available information and databases;
• Expert opinion;
• Physical surveys and monitoring;
• Desk-top studies;
• Monitoring and modelling (for example of the noise, air quality and visual
environments); and
• Reference to current best practice and guidance in relation to the
sustainability of the Proposed Development and associated
infrastructure.
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Baseline Conditions
7.2.2. In order to assess the potential effect of the Proposed Development and
associated infrastructure, it is necessary to determine the baseline conditions.
The baseline conditions are typically the current environmental and socio-
economic conditions of the DCO Site (at the time of writing the PEI Report). In
the context of the EIA for the Proposed Development Site, the existing baseline
scenario consists mainly of open grassland, crossed by a number of rhines
(drainage channels), including the Red Rhine.
7.2.3. Baseline conditions have been determined using the results of onsite surveys
and investigations or desk based data searches, or a combination of these, as
appropriate.
7.2.4. The technical chapters of this PEI Report (Chapters 9 to 19) describe as
necessary their spatial scope including their rationale for determining the specific
area within which the assessment is focussed. The study areas are a function of
the nature of the impacts and the locations of potentially affected environmental
resources or receptors.
7.2.5. The approach to assessment has been to assess the environmental impacts of
the Proposed Development at key stages in its construction and operation, and,
where possible, the decommissioning phase.
7.2.6. The 'current baseline year' is taken as 2013 (pre 01 December 2013) since this is
the period in which the baseline work for the PEI Report was undertaken.
7.2.7. The Proposed Development Site has undergone noticeable change since this
date, due to being used from mid-December 2013 by SITA for access to the
Severnside Energy Recovery Centre (which is currently under construction on
land immediately west of the Proposed Development Site) and the construction of
the Spine Access Road and new channel for the Red Rhine along the northern
boundary of the Proposed Development Site on behalf of Severnside Distribution
Land Ltd. A brief description of these other developments is presented later in
this chapter.
7.2.8. The baseline conditions onsite are therefore dynamic and will be changing week-
to-week from mid-December 2013 to the expected date of submission of this PEI
Report.
7.2.9. The description of baseline conditions will be updated for the final ES, to reflect
the state of the Proposed Development Site at the point of submitting the
Application, or at an agreed point in time shortly beforehand. Any changes to the
predicted effects and mitigation measures due to the change in baseline
conditions would also be captured in the final ES.
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7.2.10. For the purpose of this PEI Report, a ‘future baseline’ scenario has been
assumed, which takes account of the fact that the Severnside Energy Recovery
Centre, a new Red Rhine channel, and the Spine Access Road will be built by the
time enabling works start for the Proposed Development; all three of these
developments are currently under construction.
Significance Criteria
7.2.11. The significance of effects is evaluated with reference to definitive standards,
accepted criteria, and legislation where available. Where it has not been possible
to quantify effects, qualitative assessments have been carried out, based on
expert knowledge and professional judgment. Where uncertainty exists, this has
been noted in the relevant assessment chapter.
7.2.12. The significance criteria generally lead to a common outcome of classifying the
significance of effects as major, moderate, minor or negligible. Effects are also
described according to whether they are considered to be adverse, neutral or
beneficial. Methodologies and criteria definitions necessarily differ between the
different technical studies, but where possible the same language is used, such
that the significance of the residual effects can be compared.
7.2.13. Specific significance criteria for each technical discipline have been developed,
giving due regard to the following:
• Extent and magnitude of the effect;
• Duration of the effect (whether short, medium or long-term);
• Nature of the effect (whether direct or indirect, reversible or irreversible);
• Whether the effect occurs in isolation, is cumulative or interactive;
• Performance against any relevant environmental quality standards;
• Sensitivity of the receptor; and
• Compatibility with environmental policies.
7.2.14. Each of the technical chapters provides details of the significance criteria used for
quantifying residual effects, including data sources and justifications.
7.2.15. In order to provide a consistent approach across the different technical disciplines
addressed within the PEI Report, the following terminology has been used
throughout the PEI Report to define residual effects (i.e. effects post the
application of mitigation measures):
• Adverse - Detrimental or negative effects to an environmental/socio-
economic resource or receptor; or
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• Negligible - Imperceptible effects to an environmental/socio-economic
resource or receptor; or
• Beneficial - Advantageous or positive effect to an environmental /socio-
economic resource or receptor.
7.2.16. Where adverse or beneficial effects have been identified these have been
assessed against the following scale:
• Negligible
• Minor;
• Moderate; and
• Major.
7.2.17. For avoidance of doubt, moderate and major residual effects are considered
‘significant’ in terms of the EIA Regulations (Ref. 7-1). Negligible and minor
effects are not significant.
7.2.18. In the context of the Proposed Development, short to medium-term effects are
generally considered to be those associated with the construction phase; long-
term effects are those associated with the completed and operational Proposed
Development and associated infrastructure. Local effects are defined as those
affecting the DCO Site and neighbouring receptors, while effects upon receptors
in SGC and BCC (or similar scale, even if they occur across other local authority
boundaries) are considered to be at a district or regional level. Effects on different
parts of the country, or England as a whole, are considered national. Beneficial
and adverse, short and long-term (temporary and permanent), direct and indirect,
and cumulative effects have also been considered within the EIA. Where there
are no predicted effects, this is stated in the technical assessments.
7.2.19. The relationship between the sensitivity of receptors and the likely magnitude of
change caused by the effect allows the relative significance of predicted effects
on the landscape to be defined. Table 7-1 below provides a typical matrix used
by several technical assessments to describe this relationship, and so allows a
relative level of significance of any predicted effect to be categorised.
Table 7-1: Matrix Defining the Significance of Effects
Magnitude of Change
Sensitivity of Receptor
High Medium Low Very Low
High Major Major Moderate Minor
Medium Major Moderate Minor Negligible
Low Moderate Minor Negligible Negligible
Very Low Minor Negligible Negligible Negligible
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7.2.20. Where there are deviations away from the matrix as presented above, this will be
highlighted within the chapter and the reason for the variation explained. For
example, Chapter 9: Land Use, Recreation and Socio-economics does not
categorise the magnitude of change or sensitivity of a receptor, and therefore
avoids using the above matrix to determine significance of effects. This can be
justified since aspects such as the labour market and public rights of way do not
lend themselves naturally to being categorised in the manner described above.
7.2.21. Each technical chapter sets out specific measures which have been incorporated
into the design of the Proposed Development and associated infrastructure to
avoid or minimise impacts. Any mitigation measures that are to be implemented
that are considered to be standard or common throughout the construction or
power industries are also described. These include compliance with Best Practice
guidance documents (e.g. EA pollution prevention guidelines). The initial impact
assessment is undertaken giving consideration to measures already being
implemented or to be implemented as standard; for example preliminary
atmospheric dispersion modelling has determined the stack heights assessed in
this PEI Report.
7.2.22. Due to the current stage of the design process it has not been possible to specify
all measures adopted to date within this PEI Report, however any assumptions
made regarding avoidance or mitigation measures within the preliminary
assessment are summarised within the chapters.
7.2.23. Once the likely effects have been identified and quantified, consideration is given
to any additional mitigation (over and above anything identified within design
process) that may be required to mitigate any significant effects identified.
7.2.24. Finally, the residual effects once mitigation has been implemented are assessed
and presented. These residual effects are also summarised in Chapter 21:
Residual Effects.
7.3. Structure of this PEI Report
7.3.1. As discussed within Chapter 1: Introduction, this PEI Report consists of three
volumes and a Non-Technical Summary.
7.3.2. Volume I (this volume) forms the main body of the PEI Report, detailing the
results of environmental investigations, potential effects arising, and the proposed
mitigation measures. The PEI Report also identifies opportunities for social and
economic benefit and environmental enhancement. It is divided into a number of
background and technical chapters supported with figures and tabular
information.
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7.3.3. Each topic has been assigned a separate technical chapter in the PEI Report as
follows:
• Land Use, Recreation and Socio-Economics;
• Traffic and Transport;
• Air Quality;
• Noise and Vibration;
• Ground Conditions;
• Water Resources and Flood Risk;
• Cultural Heritage and Archaeology;
• Ecology;
• Landscape and Visual Impact Assessment;
• Sustainability; and
• Health.
7.3.4. In addition to the above, the following chapters are provided as part of this PEI
Report:
• Introduction;
• The DCO and EIA Process
• The Site and Its Surroundings;
• Project Description;
• Enabling Works and Construction;
• Project Need and Alternatives;
• Assessment Methodology;
• Planning Policy Context;
• Cumulative Effects
• Residual Effects; and
• Glossary of Terms.
7.3.5. Volume II Technical Appendices of this PEI Report comprises background data,
technical reports, tables, figures and surveys. The appendices provided are as
follows:
• Appendix A: EIA Scoping and Scoping Opinions;
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• Appendix B: Electronic Interference Screening Assessment;
• Appendix C: Construction Environmental Management Plan;
• Appendix D: Planning Policy;
• Appendix E: Traffic and Transport;
• Appendix F: Air Quality
• Appendix G: Noise and Vibration
• Appendix H: Archaeology
• Appendix I: Ground Conditions
• Appendix J: Flood Risk, Hydrology and Water Resources
• Appendix K: Ecology
• Appendix L: Landscape and Visual Assessment
• Appendix M: Sustainability
• Appendix N: CHP Assessment
7.3.6. Volume III of this PEI Report presents the figures referred to in this report
(Volume I).
7.3.7. The PEI Report Non-Technical Summary is presented as a separate document,
providing a concise description of Volumes I to III, including the Proposed
Development and associated infrastructure, alternatives considered, potential
environmental effects, and mitigation measures. The Non-Technical Summary is
designed to give information on the DCO Application to a wide and non-technical
audience and to assist interested parties with their familiarisation of the Proposed
Development and associated infrastructure.
7.4. Structure of PEI Report Chapters
7.4.1. The technical chapters of this PEI Report follow a common structure and format.
Within each chapter the assessment has been structured in the following way:
Introduction
7.4.2. This section describes the format of the assessment presented within the chapter
and identifies the author, as well as outlining the consultation responses relevant
to the assessment received to date. It also includes a brief summary of legislation
and applicable policies and plans relevant to the Proposed Development.
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Assessment Methodology and Significance Criteria
7.4.3. This section describes the approach taken to the assessment including the
surveys/studies and research undertaken to determine the baseline conditions
and the procedure followed to assess the effects of the Proposed Development
and associated infrastructure. Topic-specific effect significance criteria and the
standards/guidance from which they are derived are explained and definitions of
minor, moderate, and major (adverse or beneficial) and negligible effects is
provided.
Baseline Conditions
7.4.4. As discussed earlier in this chapter, the environmental conditions that currently
exist on the DCO Site (the ‘baseline conditions’) are considered and presented
within this section of each technical chapter. For all issues, the EIA baseline has
been taken as the conditions on-site prior to 01 December 2013, unless
otherwise stated. Further reference is made to aspects of the baseline that may
be sensitive to the Proposed Development and associated infrastructure, i.e.
sensitive receptors such as residential dwellings.
7.4.5. Where relevant the technical chapters present and discuss a Future Baseline
scenario. A number of other schemes are currently being progressed by third
parties onsite and adjacent to the Proposed Development Site, which will change
the baseline conditions between the submission of this PEI Report and the ES.
This includes the development of the Severnside Energy Recovery Centre to the
west of the Proposed Development Site which will use the Proposed
Development Site for the creation of a new spine road along the northern
perimeter of the Proposed Development Site, and the excavation of a new
drainage channel for the Red Rhine within the northern perimeter of the
Proposed Development Site. These projects are discussed in more detail in the
subsection ‘Cumulative Effects’.
Development Design and Impact Avoidance
7.4.6. The EIA and design process is iterative and a number of mitigation measures
have been embedded into the Proposed Development as a result of preliminary
studies or to minimise adverse effects and maximise opportunities for beneficial
effects. This section is intended to outline the design measures prior to
presenting the assessment of effects. For example, the Proposed Development
incorporates two 90m stacks for the CCGT units and two 45m stacks for the
peaking plant; these stack heights were determined through extensive
atmospheric dispersion modelling tests to achieve an acceptable effect on air
quality; this mitigation is incorporated into the description of the Proposed
Development presented in Chapter 4: Project Description.
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Potential Effects and Mitigation Measures
7.4.7. This section identifies the potential effects resulting from the Proposed
Development and associated infrastructure and considers effects during
construction and once it is completed and operational. The effects of the
Proposed Development and associated infrastructure are defined against the
existing baseline. This section also describes the mitigation measures that the
Applicant will implement to reduce adverse effects and enhance beneficial effects
relevant to the Proposed Development and associated infrastructure.
7.4.8. The various technical chapters also consider the inter-relationship of effects in
this section, also sometimes referred to as in-combination effects (effects caused
by two or more impacts of the Proposed Development in combination). In
particular these are considered in the chapters that focus on specific receptors,
such as Chapter 16: Ecology, which considers the in-combination effects of
noise, air quality, habitat loss, disturbance etc. on ecological receptors, or
Chapter 11: Air Quality for example, which may consider the effect of the stack
emissions and additional road traffic emissions together at a particular receptor.
Residual Effects
7.4.9. This section assigns significance to those effects of the Proposed Development
and associated infrastructure which remain once mitigation measures are in
place for both the construction and operational phases. It is only those residual
effects that are ‘moderate’ or ‘major’ in this PEI Report which are considered
‘significant’ in terms of the EIA Regulations.
Cumulative Effects
7.4.10. As required by the EIA Regulations (Ref. 7-1), it is important to consider the
potential for cumulative effects of the Proposed Development and associated
infrastructure when considered along with other developments planned or
consented in the vicinity of the DCO Site. Existing schemes such as Seabank 1 &
2 form part of the baseline conditions described above.
7.4.11. The assessment of cumulative effects has been based upon the information
available at the time of writing and currently available assessment techniques.
7.4.12. The schemes included within the cumulative effect assessment have been
identified in consultation with SGC and BCC, and comprise those within a 6km
radius of the Proposed Development Site and which are more than 1ha in size
(and therefore of sufficient proximity and scale to potentially lead to cumulative
effects).
7.4.13. A list of development schemes consented for planning, under construction or at
pre-planning submission stage that have been included within the cumulative
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effect assessment is provided below. The locations of these cumulative schemes
are illustrated in Figure 7-1 (Volume III of this PEI Report).
1. Avon Power Station (Scottish Power) Pre-application. A proposed
CCGT power station on the former Terra Nitrogen and ICI site in
Severnside. This has not yet reached the EIA Scoping stage and
therefore information on this scheme is sparse, limited to a preliminary
application site boundary and suggestions that it would comprise
900MWe of CCGT.
2. Severnside Energy Recovery Centre (SITA) – PT09/5982/FMW:
Granted. Development of an Energy Recovery Centre (called SERC).
The application was granted on appeal in 2011. Construction works have
begun onsite and SITA will use the Proposed Development Site for
laydown, access, and other activities associated with the construction
works.
3. Bottom Ash Facility (SITA) – APP/P0119/A/10/2140199: Granted.
Bottom Ash Facility and associated Railhead which will serve the
consented Severnside Energy Recovery Centre (SERC).
4. Spine Access Road (Severnside Distribution Land Ltd) –
PT12/1207/MW: Granted. A road linking the adjacent SERC with the
A403 (via a new 3-arm roundabout to be constructed on the A403).
Permission was granted by SGC for the access road under reference
PT09/5982/FMW, and a further application was granted planning
permission for the re-alignment of the original planned and approved
road under reference. Severnside Distribution Land Ltd intends to extend
this new Spine Access Road around the northern perimeter of the
Proposed Development Site, under the extant 1957/58 consent (which is
discussed further in bullet point 15). Construction works started in winter
2013/14.
5. Anaerobic Digestion Facility (New Earth Solution) – PT12/1015/MW:
Granted. Change of use of agricultural land to anaerobic digestion
facility including weighbridges, reception building, biofilter, digestion and
storage tanks and associated plant and infrastructure. This is currently
under construction and due to open in 2014.
6. Resource Recovery Centre (VIRIDOR) – 09/04470/F: Granted. The
construction and operation of a Resource Recovery Centre including a
materials recycling facility, associated office, visitor centre and energy
from waste and bottom ash facility, with new access road and
weighbridge facilities, associated landscaping and surface water
attenuation features.
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7. Deep-sea Container Terminal (Bristol Port Company) - 08/03387/K:
Granted. Construction of a deep-sea container terminal on the site of a
former oil terminal at Avonmouth to accommodate the existing large
container ships and future generations of Ultra Large Container Ships
(ULCS).
8. Biomass Plant (Helius Energy) – 09/00506/K: Deemed Planning
Permission Granted - Construction of Biomass fuel store and biomass
fired electricity generating plant, capable of generating approximately
100MW of electricity.
9. Bristol Resource Recovery Centre (Cyclamax) Plot M2, Merebank
Estate, Kingsweston Lane - 11/01773/F: Granted. Proposed Bristol
Resource Recovery Centre to consist of: a 100,000 tonnes per annum
batch oxidation gasification facility; a 80,000 tonnes per annum materials
recycling facility to process source segregated recyclable materials; an
end of life plastics to fuel conversion facility; a vehicle depot for waste
collection vehicles; and a temporary refuse derived fuel production facility
to be located within the proposed gasification building.
10. W4B, Former Columbian Chemicals (Sevalco), Severn Road -
09/03235/F: Granted on appeal. Redevelopment of part of existing
industrial site for a Bio-fuel energy plant together with ancillary access
roads, parking facilities and landscaping.
11. Unit and Service Centre (Asda), Former Rhodia Works, St. Andrews
Road - 12/03149/F: Granted. Redevelopment of the former Rhodia
chemical works to provide a chilled distribution unit (Use Class B8) and
an ancillary service centre (Use Class B2).
12. Rockingham Park (Terramond Ltd), – 11/05157/P: Granted. Outline
planning application for industrial redevelopment, comprising B1(b),
B1(c) and B8 uses.
13. Biomass Renewable Energy Plant (E.ON), Portbury Docks –
09/00506/K: Granted. An application to build a biomass-fired renewable
energy plant as a means of increasing electricity generation derived from
non-fossil fuels. The proposed plant would be located at the Royal
Portbury Dock, within the Port of Bristol and would be developed on a
plot of land approximately 5ha in size, leased to E.ON by The Bristol Port
Company.
14. Hinkley Point C Connection (National Grid) – DCO Application, not
yet submitted. A new 400kV connection between Bridgwater, Somerset
and Seabank Substation, north of Avonmouth. It is proposed to extend
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the existing Seabank electricity substation compound and substation
building to accommodate additional electrical plant and equipment. It
includes an OHL across the River Avon to the west of the existing 132kV
OHL and then follows the edge of Avonmouth village (travelling through
the Avonmouth Docks complex) before heading through the centre of the
industrial area and connecting into Seabank substation. An off spur of
the assessment corridor crosses the DCO Site, as illustrated in Figure 7-
1 (Volume III of this PEI Report), although it is understood this is required
for access near Poplar Roundabout rather than any works to OHLs.
15. The 1957 Consent – SG 4244: Granted. Planning permission was
granted on 27 November 1957 for a variety of uses on approximately
1,060ha of land, with an additional 10ha added by a 1958 consent, which
remains extant for future development. Approximately 405ha is approved
for industrial use – for the construction and operation of factories for the
production of chemical and allied products (including non-ferrous metals)
and for the development of offices, warehouses, canteens, clubs,
hostels, training establishments, sports pavilions and playing fields etc.
This includes the Proposed Development Site (but not the Other DCO
Land). A peripheral 220ha, mainly in the eastern portion of the consented
area, allows for the development of offices, warehouses, canteens,
clubs, hostels, training establishments, sports pavilions and playing fields
etc. A further 445ha of land extending from the coastline into the Severn
Estuary was originally approved for the construction and operation of any
buildings structures or engineering works expedient to the construction
and operation of the factories, though this was later rescinded through a
Section 106 agreement with ICI accompanying the granting of planning
permission for the development of the first phase of the Western
Approaches Business Park (P94/400/8). This agreement included the
setting aside of 38ha of land for ecology enhancements and the creation
of a number of green corridors within the 1957-58 consented land.
Developments being built under this extant planning permission include,
but are not limited to, the following:
• Spine Access Road. Severnside Distribution Land Ltd intends to extend
the new spine access road mentioned in point 4 above around the
northern perimeter of the Proposed Development Site. Enabling work
has begun on this project.
• Diversion of the Red Rhine. Severnside Distribution Land Ltd also
intends to create a new drainage channel or rhine along the northern
boundary of the Proposed Development Site under this extant consent
and with permission from the Lower Severn Internal Drainage Board. The
Red Rhine will be diverted into this new channel as part of the enabling
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works for the Proposed Development. The creation of this new channel
commenced in winter 2013/14.
• Central Park. A 240ha (600 acre) warehouse and distribution park
development, which is strategically located within the region and
designed to be the South West’s largest distribution park, capable of
accommodating units of over 850,000 square foot (sq ft). The land for
Central Park is currently being raised to protect against flood risk.
7.4.14. The need for offsite gas enforcement or cross-country pipelines has been
discounted and is not considered further in this PEI Report. National Grid’s
Strategic Options Report (November 2013) identified ten options to meet the
need case. It concluded that the optimal solution was to modify a compressor
station in Wiltshire, most likely the Lockerley and Aylesbury Compression and
Flow stations. This is currently considered the best technical solution, least cost
and most environmentally considerate option; it also requires no additional
landtake. These upgrade works would be within existing stations and therefore
not likely to give rise to cumulative effects, especially as works will be within the
existing development boundary and are located over 100km from the Proposed
Development Site. The report concluded that there should be no need for any
new cross country gas pipelines in response to the Proposed Development. The
upgrade works have therefore been scoped out of the cumulative effect
assessment.
7.4.15. The CCS has not been included as a cumulative scheme. As discussed in
Chapter 4: Project Description, an area has been reserved for the potential future
siting of carbon capture and compression equipment, should it be required at a
future date in order to meet the requirements set out in the EU CCS Directive for
Geological Storage of Carbon Dioxide and to demonstrate that the Proposed
Development is CCR. The actual design and consenting of CCS technology and
infrastructure does not form part of this DCO Application, as it is not currently
required to be installed at the Site (nor does the technology actually exist at the
present time). Any CCS infrastructure would need to be consented separately at
the time it is required in the future. However, in accordance with DECC CCR
Guidance requirements, the CCR Site is included within the Proposed
Development Site boundary and the baseline conditions are described to enable
an assessment of the use of this part of the Site for construction compound,
parking and laydown, as described in Chapter 5: Enabling Works and
Construction.
7.4.16. Details of cumulative effects are provided in each of the technical chapters of the
PEI Report. A summary of the effects is provided in Chapter 20: Cumulative
Effects of this PEI Report.
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Impacts and Effects yet to be Determined
7.4.17. This section of the technical chapters provides a brief description of any
information not yet provided in the PEI Report which is intended to be included in
the final ES. This includes any survey data not yet collected and any impacts or
effects yet to be assessed.
7.4.18. Where there are no impacts and effects yet to be determined, this is noted. It is
recognised however, that the scheme design may be subject to change prior to
submission of the final DCO Application, following receipt of comments on this
PEI Report. Any changes that lead to differing or new impacts and effects will be
highlighted within the final ES, along with the reasons for the change.
7.5. Assumptions and Limitations
7.5.1. A number of general assumptions have been made during the EIA, which are set
out below. Assumptions specific to certain environmental aspects are discussed
in the relevant PEI Report chapters:
• Information provided by third parties, including publicly available
information and databases is correct at the time of publication;
• The construction programme associated with the Proposed Development
and associated infrastructure is indicative at this stage;
• Baseline conditions are accurate at the time of the physical surveys,
which were undertaken prior to 01 December 2013, but, due to the
dynamic nature of the environment, conditions will change prior to or
during the construction phase and on completion and operation of the
DCO Site. In particular, at the time of writing SITA and Severnside
Distribution Land Ltd have begun works on the SERC, Red Rhine
diversion and new Spine Access Road, which are all expected to
substantially change the baseline conditions within the Proposed
Development Site;
• Further intrusive on site work may be required in respect of ground
conditions, geotechnical and sub-surface archaeological remains
following receipt of planning permission so as to finalise substructure
construction methods; and
• The assessment of cumulative effects has been reliant on the availability
of information relating to all of the identified cumulative schemes
(whether submitted for planning, consented or under construction).
7.6. References
Ref. 7-1 HMSO (2009); Infrastructure Planning (Environmental Impact Assessment) Regulations
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PEI Report – Chapter 8 Planning Policy Context
8. Planning Policy Context
8.1. Introduction
8.1.1. This chapter outlines the overarching planning policy context for the Proposed Development, providing an overview of the relevant planning and energy policy framework which are material to the DCO Application.
8.1.2. This includes the relevant requirements of the National Policy Statements (NPSs), in accordance with which the National Infrastructure Directorate of the Planning Inspectorate is required to examine, and the Secretary of State (SoS) for Energy and Climate Change is required to determine, the DCO Application.
8.1.3. A more detailed review of legislative and policy matters will be provided in a Planning Statement that will form part of the DCO Application. A summary of the specific national and local planning polices relevant to each technical chapter is provided within Appendix D, Volume II of this PEI Report, along with any legislative requirements that need to be taken into account by the Proposed Development.
8.2. The Planning Act and National Policy Statements for Energy
8.2.1. The Planning Act 2008 (as amended) (Ref. 8-1) establishes a regime for grating DCOs for NSIPs and provides for the Government to produce NPSs. Responsibility for receiving and examining DCO applications lies with the Planning Inspectorate, which will make a recommendation to the relevant SoS.
8.2.2. The Planning Act 2008 enables the SoS to designate a statement as a NPS, if it sets out national policy in relation to specified descriptions of nationally significant infrastructure development. A number of NPSs relating to energy infrastructure (including technology specific NPSs) were designated by the SoS for the Department of Energy and Climate Change (DECC) in July 2011.
8.2.3. The Proposed Development will produce up to 1,400MWe net from combusting natural gas (using some distillate fuel in the case of a black start event), and therefore exceeds the 50MWe criterion set out in the Planning Act and NPSs for NSIPs. As such, the designated NPSs listed below are considered relevant to the determination of this DCO Application.
• Overarching NPS for Energy EN-1 (Ref. 8-2): This document sets out national policy for energy infrastructure as defined by the Planning Act and provides an umbrella document under which all other energy NPSs sit. The policies within this NPS, in combination with policies set out in relevant technology specific energy NPSs, provide the primary basis for
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PEI Report – Chapter 8 Planning Policy Context
decisions by the SoS for Energy and Climate Change (the Secretary of State) and set out the need for new energy infrastructure.
• NPS for Fossil Fuel Electricity Generating Infrastructure (EN-2) (Ref. 8-3): This sets out policies specific to the determination of applications for fossil fuel electricity generating infrastructure.
• NPS for Electricity Networks Infrastructure (EN-5) (Ref. 8.4): This sets out the policies specific to the determination of applications for above ground electricity lines whose nominal voltage is expected to be 132kV or above.
8.2.4. Part 3 of EN-1 defines and sets out the ‘need’ that exists for nationally significant energy infrastructure. Paragraph 3.1.1 states that the UK needs all the types of energy infrastructure covered by the NPS in order to achieve energy security at the same time as dramatically reducing greenhouse gas emissions. Paragraph 3.1.2 of the NPS goes on to state that it is for industry to propose new energy infrastructure and the Government does not consider it appropriate for planning policy to set targets for or limits on different technologies.
8.2.5. Notably, paragraph 3.1.3 of the NPS stresses that the SoS should assess applications for Development Consent for the types of infrastructure covered by the energy NPSs on the basis that the Government has demonstrated that there is a need for those types of infrastructure. Paragraph 3.1.4 of the NPS continues that the SoS should give substantial weight to the contribution that projects would make towards satisfying this need. As such, the ‘need’ for energy infrastructure is not open to debate or interpretation.
8.2.6. In making decisions on NSIPs, the SoS must also have regard to any local impact report submitted by a relevant local authority, any relevant matters prescribed in regulations and other matters that the SoS thinks are both important and relevant to his/her decision. Other matters that may be considered both important and relevant may include local development plan documents (DPDs). The NPSs provide guidance on assessment principles and identify a number of generic impacts relating to energy infrastructure that applicants should consider in preparing their application and which the SoS should have regard to in determining applications.
8.2.7. The SoS is required to determine applications for Development Consent in accordance with the relevant NPSs unless this would:
• Lead to the UK being in breach of its international obligations;
• Be in breach of any statutory duty that applies to the SoS;
• Be unlawful by virtue of any enactment;
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PEI Report – Chapter 8 Planning Policy Context
• Result in adverse impacts from the development outweighing the
benefits; or
• Result in any condition prescribed for deciding an application otherwise than in accordance with a national policy statement being met.
8.2.8. The energy NPSs also provide guidance on the principles to be applied in assessing applications for Development Consent and identify a number of generic and technology specific impacts relating to energy infrastructure that applicants should consider in preparing their applications and which the SoS should have regard to in making decisions.
8.2.9. The scope of the EIA undertaken will address the requirements set out in the energy NPSs EN-1 (Ref 7-1), EN-2 (Ref 7-2) and EN-5 (Ref 7-3). In particular, the scope will take account of EN-1 Part 4 ‘Assessment Principles’ and Part 5 ‘Generic Impacts’ and EN-2 Part 2 ‘Assessment and technology-specific information’. In relation to EN-2 Part 2 the relevant matters will be considered in the EIA on a topic-by-topic basis, which will include specifying what is required in terms of an ‘applicant’s assessment’ and ‘decision making’ and 'mitigation'.
8.2.10. The requirements of the NPSs, as well as local planning policies, are considered in detail in each of the specialist assessment chapters contained in this PEI Report, with an overview of the specific policies presented in Appendix D, Volume II of this report. The final ES to be submitted with the DCO Application will include a record of how relevant NPS policy requirements have been considered and will provide information needed to determine the application in accordance with the NPSs.
8.2.11. The need for the Proposed Development is discussed in Chapter 6: Project Need and Alternatives of this PEI Report. Compliance with planning policy will also be considered within the DCO Application Supporting Statement, submitted with the DCO Application.
8.3. Other Relevant National Policy
8.3.1. NPS EN-1 states that consideration may be given to planning policy outside the NPSs where it is important and relevant to the SoS’s decision. NPS EN-1 states in paragraph 4.1.5 that where there is any conflict between an NPS and another policy document, the NPS shall prevail for the purposes of determination of an application for a DCO by the SoS.
8.3.2. Other national planning policies have been considered in the preparation of this PEI Report and, where relevant, are described further in each of the topic chapters. National planning policy is predominantly contained in the National Planning Policy Framework (NPPF) (Ref. 8-5). The NPPF does not contain
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specific policies for nationally significant infrastructure projects, but its policies can be relevant to the determination of a DCO Application.
8.3.3. The following National Planning Policy and Guidance are adopted:
• NPPF – sets out national planning policy and how this should be applied.
• NPPF Technical Guidance (Ref. 8-6) – seeks to ensure the effective implementation of the NPPF in areas at risk of flooding and in relation to minerals extraction.
8.4. Local Planning Policy
The Development Plan 8.4.1. The DCO Site boundary includes land within the administrative areas of SGC and
BCC. The adopted Development Plan for the anticipated DCO Site, as defined by Section 38 (6) of the Planning and Compulsory Act 2004 (Ref. 8-7), includes the documents listed below.
Adopted Development Plan – South Gloucestershire Council
8.4.2. The following documents form the Adopted Development Plan for SGC:
• South Gloucestershire Core Strategy 2006 - 2027 (Ref. 8-8).
• South Gloucestershire Local Plan, adopted 2006 (saved policies) (Ref. 8-9).
• West of England Joint Waste Core Strategy, adopted March 2011 (Ref. 8-10).
• South Gloucestershire Minerals and Waste Local Plan, adopted 2002 (saved policies) (Ref. 8-11).
Adopted Development Plan – Bristol City Council
8.4.3. The following documents form the Adopted Development Plan for BCC:
• Bristol Core Strategy, adopted June 2011 (Ref. 8-12).
• Bristol Local Plan, adopted 1997 (saved policies) (Ref. 8-13).
• West of England Joint Waste Core Strategy, March 2011 (Ref. 8-10).
The Emerging Development Plan
8.4.4. SGC and BCC are also in the process of preparing new development plan documents. These emerging development plan documents are listed below.
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PEI Report – Chapter 8 Planning Policy Context
Emerging Development Plan Documents
8.4.5. BCC has drafted the Bristol Site Allocations and Development Management Development Plan Document (Ref. 8-14).
8.4.6. The Bristol Site Allocations and Development Management Policies Publication Version was submitted to the SoS on 12 July 2013 for independent examination.
8.4.7. The policies of this emerging development plan document have not yet been adopted, but could be material to the DCO Application, especially if they have undergone public disclosure.
8.4.8. Whilst not part of the development plan under the Planning and Compulsory Purchase Act 2004, the emerging development plan document has been taken into account in the preparation of this PEI Report and, where relevant, is considered further within each of the topic chapters.
Other Local Policy
8.4.9. Other local policy documents can be taken into account in the determination of the applications for DCO if the SoS considers them important and relevant.
8.4.10. SGC has prepared the Supplementary Planning Documents (SPDs) and Supplementary Planning Guidance (SPGs) listed below, which could be relevant to the consideration of the DCO Application:
• South Gloucestershire Planning Guidance: Biodiversity in the Planning Process (SPG), adopted November 2005 (Ref. 8-15);
• South Gloucestershire Design Guide: Sustainable Drainage Systems (SPG), adopted 2002 (Ref. 8-16);
• South Gloucestershire Planning Guidance: Trees on Development Sites (SPG), adopted November 2005 (Ref. 8-17);
• South Gloucestershire Design Guide: Waste Audits (SPG), adopted July 2002 (Ref. 8-18);
• South Gloucestershire Landscape Character Assessment SPD, adopted July 2005 (Ref. 8-19);
• South Gloucestershire Design Checklist SPD, adopted August 2007 (Ref. 8-20).
8.4.11. SPDs and SPGs adopted by BCC, which may be relevant to the consideration of the DCO Application, include the documents listed below.
• Waste and Recycling: Collection and Storage Facilities – Guidance for developers, owners and occupiers, January 2010 (Ref. 8-21);
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PEI Report – Chapter 8 Planning Policy Context
• Supplementary Planning Document 1: Tall Buildings, adopted January
2005 (Ref. 8-22);
• Supplementary Planning Document 5: Sustainable Building Design and Construction, adopted February 2006 (Ref. 8-23);
• Supplementary Planning Document 7: Archaeology and Development, adopted March 2006 (Ref. 8-24);
• Bristol Local Plan Policy Advice Note 2: Conservation Area Enhancement Statements; November 1993 (Ref. 8-25);
• Bristol Local Plan Policy Advice Note 14: Safety and Security, June 1997 (Ref. 8-26);
• Bristol Local Plan Policy Advice Note 15: Responding to Local Character, March 1998 (Ref. 8-27).
8.5. References
Ref. 8-1 Planning Act 2008 (Great Britain) Ref. 8-2 Department for Energy and Climate Change (2011) Overarching
National Policy Statement for Energy (EN-1) Ref. 8-3 Department for Energy and Climate Change (2011) National Policy
Statement for Fossil Fuel Electricity Generating Infrastructure (EN-2) Ref. 8-4 Department for Energy and Climate Change (2011) National Policy
Statement for Electricity Networks Infrastructure (EN-5) Ref. 8-5 Department for Communities and Local Government (2012) National
Planning Policy Framework Ref. 8-6 Department for Communities and Local Government (2012) Technical
Guidance to the National Planning Policy Framework Ref. 8-7 Planning and Compulsory Purchase Act 2004 (Great Britain) Ref. 8-8 South Gloucestershire Council (2013) South Gloucestershire: Core
Strategy 2006 – 2027, Adopted December 2013 Ref. 8-9 South Gloucestershire Council (2006) South Gloucestershire Local
Plan (saved policies) Ref. 8-10 West of England Partnership (2011) West of England Joint Waste
Core Strategy Ref. 8-11 South Gloucestershire Council (2002) South Gloucestershire Minerals
and Waste Local Plan (saved policies) Ref. 8-12 Bristol City Council (2011) Bristol Core Strategy Ref. 8-13 Bristol City Council (1997) Bristol Local Plan (saved policies) Ref. 8-14 Bristol City Council (2013) Bristol Site Allocations and Development
Management Development Plan Document Publication Version Ref. 8-15 South Gloucestershire Council (2005) South Gloucestershire
Planning Guidance: Biodiversity in the Planning Process, adopted November 2005
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PEI Report – Chapter 8 Planning Policy Context
Ref. 8-16 South Gloucestershire Council (2002) South Gloucestershire Design
Guide: Sustainable Drainage Systems SPG Ref. 8-17 South Gloucestershire Council (2005) South Gloucestershire
Planning Guidance: Trees on Development Sites SPG Ref. 8-18 South Gloucestershire Council (2002) South Gloucestershire Design
Guide: Waste Audits SPG Ref. 8-19 South Gloucestershire Council (2005) South Gloucestershire
Landscape Character Assessment SPD Ref. 8-20 South Gloucestershire Council (2007) South Gloucestershire Design
Checklist SPD Ref. 8-21 Bristol City Council (2010) Waste and Recycling: Collection and
Storage Facilities – Guidance for developers, owners and occupiers Ref. 8-22 Bristol City Council (2005) Supplementary Planning Document 1: Tall
Buildings Ref. 8-23 Bristol City Council (2006) Supplementary Planning Document 5:
Sustainable Building Design and Construction Ref. 8-24 Bristol City Council (2006) Supplementary Planning Document 7:
Archaeology and Development Ref. 8-25 Bristol City Council (1993) Bristol Local Plan Policy Advice Note 2:
Conservation Area Enhancement Statements Ref. 8-26 Bristol City Council (1997) Bristol Local Plan Policy Advice Note 14:
Safety and Security Ref. 8-27 Bristol City Council (1998) Bristol Local Plan Policy Advice Note 15:
Responding to Local Character
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9. Land Use, Recreation and Socio-economics
9.1. Introduction
9.1.1. This chapter of the PEI Report assesses the land use, recreational and socio-
economic effects of the Proposed Development and associated infrastructure. In
particular, this chapter comprises:
• An economic impact assessment, including employment impacts on the
labour market and additional local spending; and
• Consideration of the effect on land use and recreational activity resulting
from the Proposed Development and associated infrastructure.
9.1.2. This chapter describes the assessment methods and significant criteria used;
baseline conditions; potential direct, indirect and induced effects during the
construction, operational and decommissioning phases of the Proposed
Development and associated infrastructure; any mitigation measures to maximise
local regeneration opportunities; and wider land use, recreation and socio-
economic effects.
Consultation
9.1.3. A scoping request was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on the proposed structure,
methodology and content of this chapter and subsequent ES. A summary of
stakeholder comments and how they have been incorporated into this PEI Report
chapter is provided in Table 9-1.
Table 9-1: Relevant Scoping Opinion Responses
Stakeholder Comment Addressed within the Report
Planning Inspectorate
The Applicant should engage with Natural England to determine the potential for impacts associated with diverting a public right of way.
No rights of ways will be permanently diverted. A new public right of way will be created, which is discussed in section 9.5 of this chapter.
The types of jobs generated should be considered in the context of the available workforce in the area, this applies equally to the construction and operational stages.
See section 9.5 of this chapter.
The assessment criteria should be locationally specific and consider the potential significance of the impacts of the proposal within the local and regional context.
See section 9.3 of this chapter.
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Stakeholder Comment Addressed within the Report
Land use both within and outside of the site should be considered within the ES and should include an assessment of whether the proposed power station is likely to result in constraints on adjacent land uses.
See section 9.4 and 9.5.
Details should be provided outlining proposed measures to ensure the safe use of public rights of way during the construction phase of the development.
See section 9.5 of this chapter and Chapter 10: Traffic and Transport
The assessment of the effects of the proposed development on agricultural land should be included within the ES.
As explained in Chapter 2: The DCO and EIA Process, this PEI Report does not assess the Site’s agricultural potential (which is considered to be low).
The effect of atmospheric emissions on surrounding agricultural land is assessed in Chapter 11: Air Quality.
The impacts upon users of the Severn Estuary should be assessed within the ES and should include impacts on both commercial and recreational sailing and fishing.
This comment has been superseded by the decision not to include direct cooling (which would have required a pipeline into the estuary) - see Chapter 6: Project Need and Alternatives. Given there will be no marine effects associated with the Proposed Development this has therefore been scoped out of the assessment.
SGC It is recommended, for clarity and because of the very different issues of land use and socio economics versus recreation (relating to public rights of way and bridleways), that these issues are split into separate sections of the EIA.
Sections 9.4 and 9.5 of this chapter provide separate subheadings for land use and socio economics verses recreation.
The EIA should consider the wider context of proposed access links for horses and other users including the Local Plan LC12 routes and a future link with Minors Lane.
See section and 9.5 of this chapter.
It will also be important to consider whether the proposed development has any bearing on or constraint to adjacent land uses.
See section and 9.5 of this chapter.
BCC No additional comments -
Legislation and Planning Policy Context
9.1.4. A summary of legislation and planning policy relevant to this assessment is
provided in Appendix D: Volume II of this PEI Report.
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9.2. Assessment Methodology and Significance Criteria
9.2.1. This assessment seeks to establish the potential economic and social effects of
the Proposed Development and associated infrastructure and assess these
effects against the current baseline. The effects of the Proposed Development
and associated infrastructure are considered at defined spatial levels according
to the nature of the impact considered. This approach is consistent with the
Department for Business Innovation and Skills (BIS) publication ‘Research to
Improve the Assessment of Additionality’ (Ref. 9-1).
Assessment Methodology
9.2.2. The following assessment seeks to establish the potential economic and social
contributions of the Proposed Development and associated infrastructure, and
assesses the expected effects against the current baseline position. A range of
data sources, including the Office for National Statistics, Nomis, and Annual
Business Inquiry (ABI) have been used to establish the baseline. Other
secondary sources have also been used and guidance taken from HM Treasury’s
Green Book.
9.2.3. The principal economic effect of the Proposed Development is considered
relative to the Travel to Work Area (TTWA) for the DCO Site, which includes
Bristol, South Gloucestershire, and North Somerset in the ‘Bristol TTWA’.
9.2.4. It is anticipated that as the Proposed Development Site is located in South
Gloucestershire and close to Bristol, the project TTWA will fit with that of the
Bristol TTWA. The 2001 Census indicates that 88.2% of workers live inside the
Bristol TTWA whilst 11.8% live outside (Ref. 9-2). The population of Bristol and
South Gloucestershire is therefore considered to be an appropriate study area for
the Proposed Development. This labour market incorporates the population that
may reasonably be expected to travel to, and benefit from, the Proposed
Development.
9.2.5. Impacts on social and community infrastructure vary by geographical impact
areas, according to the latest socio-economic data or policy available.
9.2.6. Table 9-2 presents the different components of the assessment and the
geographical scale at which they are assessed.
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Table 9-2: Socio-economic Effects by Geographical Scale
Effect Geographical Area of Effect
Study Area for this assessment
Employment generation during construction and operation phases (direct, indirect and induced impacts)
Bristol, South Gloucestershire
TTWA
Additional local spending Bristol, South Gloucestershire
TTWA
Changes in land use and effects on PROW Immediate area DCO Site and immediate surrounds
Effects on local tourism and visitor numbers Immediate area DCO Site and immediate surrounds
9.2.7. The scale of significance described below, together with expert judgment has
been used to assess the potential and residual effects of the Proposed
Development and associated infrastructure against the baseline conditions.
9.2.8. The assessment has been based on the maximum design parameters, which
assumes two HRSG and turbine buildings (i.e. two CCGT units) and a peaking
plant facility, with associated development and infrastructure. It is feasible that
the effects assessed in this chapter may be overestimated if the Proposed
Development is not fully built out (e.g. if one CCGT unit is constructed), however
although this might affect the number of jobs and spending created, it is not
expected to change the level of significance that has been assigned to the
residual effects. The employment numbers would also be similar regardless of
whether the maximum and minimum parameters laid out in Chapter 4: Project
Description was implemented.
Significance Criteria
9.2.9. In line with the criteria set out in Chapter 7: Assessment Methodology, effects
have been classified as either:
• Adverse - Detrimental or negative effects to an environmental/socio-
economic resource or receptor; or
• Beneficial - Advantageous or positive effect to an environmental /socio-
economic resource or receptor.
9.2.10. The magnitude of a change caused by an effect is its severity or scale. The
magnitude of a change reflects consideration of information and analysis relating
(dependent on the type of receptor) variously to (where relevant):
• Spatial extent of the effect - Local level (DCO Site or neighbouring
receptors); District level (i.e. within Bristol / South Gloucestershire);
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Regional level (South West England region), National level (UK); or
International level.
• Duration (short to medium term [generally associated with the
construction phase], and long-term effects are those associated with the
completed and operational Proposed Development
• Permanency of the effect – reversible or permanent
9.2.11. For effects described as Beneficial or Adverse, significance levels are defined as:
• Negligible – Imperceptible change, either due to its magnitude, extent or
duration, which is clearly not significant; or
• Minor - Slight, very short or highly localised effect that is not significant;
or
• Moderate - Limited effect (by extent, duration or magnitude) but which
may be considered significant; or
• Major - Considerable effect (by extent, duration or magnitude) of more
than local significance which is clearly significant.
9.2.12. Moderate and major effects are judged to be significant for the purposes of this
assessment and the wider EIA.
9.2.13. The complexity of interactions between these factors when affecting socio-
economic receptors means that it has not been considered appropriate to set out
precise quantitative measures for this chapter. However, the assessment process
has ascertained information in respect to the above factors and professional
judgement has been employed to evaluate the significance of the effects.
Key Parameters for Assessment
9.2.14. This assessment employs the ‘Rochdale Envelope’ approach (as detailed in the
Planning Inspectorate Advice Note 9) and described in Chapter 2: The DCO and
EIA Process.
9.2.15. The variation in building dimensions presented in Chapter 4: Project Description
under the ‘Rochdale Envelope’ principle is an important consideration for this PEI
Report. However it is not considered that the flexibility in building location or
heights and footprints would have a material effect on this assessment. As noted
above, the programme and number of workers would be similar regardless of this
level of flexibility and would not affect the conclusions of this assessment.
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9.3. Baseline Conditions
9.3.1. This section establishes the current baseline with regards to the following
characteristics relevant to the Proposed Development and associated
infrastructure:
• Population;
• Skills and Education;
• Economy;
• Labour Profile;
• Land Use; and
• Tourism.
9.3.2. Potential effects arising from the Proposed Development are assessed relative to
the baseline effect areas set out in Table 9-1 and benchmarked against regional
and national standards where appropriate.
Population
9.3.3. The population of the study area, which comprises Bristol and South
Gloucestershire, increased by 8.7% from 637,500 in 2002 to 698,600 in 2012
(Ref. 9-3). Over the same period the population of South West England
increased by 6.8% and the population of the UK increased by 6.8% (Ref. 9-4).
Skills and Education
9.3.4. The working age population (defined as 16 to 64 by the Office for National
Statistics (ONS)) in the study area is well skilled compared to the rest of South
West England and the UK. In 2012, 38.6% of the study area’s working aged
population had an NVQ4 or higher, compared to 34.1% in South West England
and 34.2% in the UK (Ref. 9-4).
9.3.5. 8.1% of its working age population in the study area is shown to have no
qualifications, compared to 7.0% in South West England and 9.9% in the UK.
9.3.6. Table 9-3 outlines the qualification levels of the study area population, compared
to South West England and the UK.
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Table 9-3: Qualification Levels of the Working Population (aged 16-64)
Qualification Study Area South West England
United Kingdom
NVQ4+ 38.6% 34.1% 34.2%
NVQ3 17.0% 18.8% 17.1%
NVQ2 16.0% 18.2% 16.8%
NVQ1 11.9% 12.9% 12.1%
Other Qualifications 5.4% 4.9% 6.3%
No Qualifications 8.1% 7.0% 9.9%
Source: ONS (2013); Annual Population Survey
Economy
9.3.7. The study area had a working age population of 493,500 between July 2012 to
June 2013, 80.0% of which were economically active (Ref. 9-4). For comparison,
79.0% of the working age population in South West England were economically
active during this same period, whilst the UK had a rate of 77.1% (Ref. 9-4).
9.3.8. The employment rate of the study area was 73.4%, which was lower than South
West England, which had a rate of 74.3%, although higher than the UK’s rate of
71.0% (Ref. 9-4).
9.3.9. The unemployment rate was higher in the study area (8.3%) than either South
West England (6.0%) or the UK (8.0%) (Ref. 9-4).
Labour Profile
9.3.10. The study area has a high proportion of people employed in professional
occupations (23.1%) than in both South West England (18.8%) and UK (19.6%)
(Ref. 9-4). However it also has a slightly lower proportion of people employed as
managers, directors and senior officials (10.0%) than the South West England
(10.3%) or UK averages (10.1%) (Ref. 9-4).
9.3.11. Fewer people are employed in elementary occupations in the study area (10.5%)
when compared to South West England (11.3%) and the UK (10.9%) (Ref. 9-4).
9.3.12. The distribution of employment by occupation is outlined below in Table 9-4
below.
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Table 9-4: Employment by Occupation, July 2012 to June 2013
Occupation Study Area
(%) South
West (%) UK (%)
Managers, directors and senior officials 10.0 10.3 10.1
Professional occupations 23.1 18.8 19.6
Associate prof & tech occupations 14.1 13.7 13.9
Administrative and secretarial occupations 10.5 10.7 10.9
Skilled trades occupations 10.1 12.2 10.6
Caring, leisure and other service occupations 8.1 9.1 9.0
Sales and customer service occupations 8.1 7.7 8.0
Process, plant and machine operatives 5.3 5.7 6.3
Elementary occupations 10.5 11.3 10.9
Source: Annual Population Survey 2013
9.3.13. The work force in the study area are employed across a range of sectors, with
wholesale and retail trade and the repair of motor vehicles employing the
greatest proportion of workers, which is 15.0% (Ref. 9-5). This is slightly less than
the 17.2% in South West England and 16.0% in Great Britain for this sector (Ref.
9-5). The Avonmouth Severnside Outline Development Strategy (Ref. 9-6)
highlights the ‘Distribution and Logistics’ sector as a key sector locally given the
scale of employment it supports.
9.3.14. The study area has a greater proportion of people employed in services (such as
professional, scientific and technical activities) than South West England or Great
Britain. However, it also has a smaller proportion of people employed in
manufacturing and utilities related activities than South West England and Great
Britain. The distribution of employment across sectors is outlined in Table 9-5
below.
9.3.15. Of direct relevance to the Proposed Development, approximately 750 people
(0.2%) of the labour market were employed in electricity, gas, steam and air
conditioning activities (Ref. 9-11). This is half the proportion for this sector
compared to South West England (0.4%) and Great Britain (0.4%) (Ref. 9-5).
However, the energy sector is considered a key sector within the Avonmouth
Severnside Outline Development Strategy (Ref. 9-6) despite its relatively low
share of employment.
9.3.16. The construction sector accounts for 4.4% of employment, in line with the
national average. This accounts for approximately 17,200 people in the local
labour market.
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Table 9-5: Sector Employment Distribution, 2012
Sector Study Area (% of
employment)
South West (%)
Great Britain (%)
Agriculture, forestry and fishing 0.0 1.2 0.8
Mining and quarrying 0.1 0.1 0.2
Manufacturing 7.5 9.8 8.6
Electricity, gas, steam and air conditioning supply
0.2 0.4 0.4
Water supply; sewerage, waste management and remediation activities
0.6 0.8 0.7
Construction 4.4 4.5 4.5
Wholesale and retail trade; repair of motor vehicles and motorcycles
15.0 17.2 16.0
Transportation and storage 4.1 3.6 4.5
Accommodation and food service activities 5.8 8.6 6.8
Information and communication 4.4 2.9 3.9
Financial and insurance activities 6.8 3.6 3.9
Real estate activities 1.5 1.6 1.6
Professional, scientific and technical activities 8.4 6.0 7.5
Administrative and support service activities 9.1 6.3 8.3
Public administration and defence; compulsory social security
6.4 5.1 5.0
Education 9.1 9.8 9.5
Human health and social work activities 13.1 14.2 13.4
Arts, entertainment and recreation 1.8 2.3 2.5
Other service activities 1.8 2.0 1.9
Total 100.0 100.0 100.0
Source: Business Register and Employment Survey 2012
Land Use
9.3.17. Chapter 3: The Site and Its Surroundings provides a description of the land uses
within close proximity to the Proposed Development.
9.3.18. In summary, the Proposed Development Site is predominantly grass fields,
dissected by rhines, located on the periphery of an existing industrial area. The
nearest residential communities include Severn Beach, Hallen, Pilning and
Easter Compton, approximately 1.5km north, 2km south east, 2.2km north east
and 3km east of the Proposed Development Site respectively. Isolated dwellings
are located 1.1km to the east of the Proposed Development Site.
9.3.19. The proposed below ground cooling water pipeline will follow the route of the
existing Wessex Water supply and return pipelines to the Seabank 1 & 2
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generating station, which are beneath or adjacent to a number of PROW and
extends along grass verges and existing hardstanding within the Severnside and
Avonmouth industrial areas to the Bristol WWTW.
Public Rights of Way (PROW)
9.3.20. There are a number of recognised PROW within close proximity to the DCO Site
as illustrated in Figure 3-4a, Figure 4-4b and Figure 3-4c, Volume III of this PEI
Report.
9.3.21. The closest PROW to the Proposed Development Site extends from Minor’s Lane
for approximately 450m, to the west of Minor’s Farm (derelict) and across farm
land, currently ceasing at the southern boundary of the Proposed Development
Site. No PROWs currently exist within the Proposed Development Site itself.
9.3.22. There are also a number of PROWs close to or within the DCO Site. The
proposed cooling water pipeline corridor extends along the route of an existing
PROW alongside the railway track, around St Martin’s Industrial Park and within
close proximity to Moorend Farm Avenue.
Leisure and Recreational Activities
9.3.23. The Proposed Development Site primarily comprises open grass fields dissected
by a network of rhines. It is likely that only limited leisure or recreational activity
such as dog walking, rambling, horse-riding, cycling and jogging takes place in
the vicinity of the Proposed Development. This is because there are no formal
leisure facilities nearby and the nearest settlement is approximately 2.5km away,
which would deter many recreational users. The high concentration of industrial
land uses within the area is also likely to deter leisure users and the M49 creates
a barrier effect from the east.
9.3.24. Open grass fields of similar quality to those near to the DCO Site can be found
closer to local communities. These are therefore more likely to be used for leisure
and recreational uses than those near to the DCO Site.
Tourism
9.3.25. VisitEngland (Ref. 9-7) publishes figures relating to visitor volumes and the value
of the tourism industry on a national, regional and Local Authority level. The
tourism sector in South West England is strong with a total of 19.2 million
domestic overnight trips in South West England, accounting for 20% of all trips in
England and generating £3,606m in tourism spend. In addition, 2.1 million
inbound trips in South West England generated an estimated £902m in spend.
Tourism is also an important part of South Gloucestershire’s economy with 4.6
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million day visits and 1.5 million overnight stays per year generating around £300
million in tourism related spend.
9.3.26. The local area within close proximity to the DCO Site does not have significant
historic features, landscapes or tourism attractions, with the exception of Blaise
Castle Estate - a 650 acre Grade II* registered parkland including children's play
area, museum and castle, which is approximately 4km southeast from the
Proposed Development Site. The Estate is open daily and is free to enter. It
includes the Blaise Castle Museum and Blaise Hamlet which is a National Trust
property, both of which are tourist destinations that attract approximately 530,000
visitors a year (Ref. 9-8).
9.3.27. The Castle Estate is ranked outside the top 20 free visitor attractions in South
West England, all of which attract at least 625,000 visitors a year (Ref. 9-9).
9.3.28. Urban development, woodland, farmland and the M5 and M49 lie between Blaise
Castle and the DCO Site forming significant separation. Neither site is visible
from the other.
9.3.29. There are a significant number of other historical features and tourism attractions
in the study area, given Bristol’s status as one of the UK’s most significant
historic cities. None of these tourism features are within 5km of the Proposed
Development and associated infrastructure however and are unlikely to be
affected by either the construction or operational development. These sites have
not been considered further therefore.
9.4. Development Design and Impact Avoidance
9.4.1. There are limited avoidance measures that have been implemented in the design
of the Proposed Development relevant to land use, recreation and socio-
economics.
9.4.2. The Proposed Development does however incorporate a proposed PROW that
would connect Ableton Lane to the south of the Proposed Development Site to
the existing roundabout that is situated immediately east of the Proposed
Development Site, via a new cycle path, footpath and bridleway that would
extend along the southern boundary of the CCR Site, as illustrated in Figure 4-2
and 4-3 in Volume III of this PEI Report. This is discussed further below.
9.4.3. Additional mitigation measures and industry standard control measures are
discussed in the following section.
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9.5. Potential Effects and Mitigation Measures
9.5.1. This section analyses the scale, duration (e.g. short-term, medium-term or long-
term) and significance of potential socio-economic effects attributed to the
Proposed Development and associated infrastructure against the baseline
established in the previous sections.
9.5.2. This section does not include cumulative schemes; this is addressed in section
9.7.
Construction Employment
9.5.3. The following sub-sections assess the net impact of the Proposed Development
and associated infrastructure in terms of construction jobs on the local and
regional economies of the Bristol TTWA and South West England.
9.5.4. The enabling works and construction period for the DCO Site is expected to last
54 months, as described in Chapter 5: Enabling Works and Construction. This
section focusses on the construction phase (following enabling works), which is
expected to last around 37 months and will result in greater socio-economic
effects than the enabling works.
Direct Construction Employment
9.5.5. The employment resulting from the construction phase has been calculated
based on the construction schedule provided by one of the possible construction
contractors based on work done on a number of previous and similar projects. It
excludes the 17 months of enabling works, which may be undertaken by a
separate Contractor and is expected to employ a smaller number of workers (an
expected 5- 20 workers onsite).
9.5.6. The schedule indicates that the number of construction workers will vary from a
minimum of around 25 in the first month to a peak of 800 in the 25th month of
construction (anticipated to occur in late 2019 based on the current expected
programme), and falling to around 130 in the final month prior to commissioning.
Onsite construction employment is expected to be significantly lower in the first
eight and final three months of construction. The profile of construction
employment (excluding enabling works) is presented in Plate 9-1 below.
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Plate 9-1: Profile of Construction Employment (excluding enabling works)
9.5.7. Based on the peak year of construction (from month 18 to month 29 of the
construction activities, which is expected to coincide with 2019), the expected
average workers per year generated by the Proposed Development construction
phase is 761 gross full time equivalents (FTEs). The average workers per year
generated over the entire 37 month construction period is 411.
9.5.8. Construction of the associated infrastructure related to the Proposed
Development, in particular the proposed cooling water pipeline, would also
generate additional construction employment, although this would be small in
comparison to the above. The construction of the electrical connection and
cooling water pipeline is expected to take approximately two years and would
create an estimated 100 full time equivalent jobs over this relatively short period.
Leakage
9.5.9. Leakage effects are the benefits to those outside the affected area. Analysis
carried out on Census 2001 data indicates that 11.8% of people working in the
Bristol TTWA live outside the TTWA (Ref. 9-2). This represents a ‘low’ level of
leakage as set out by BIS (Ref. 9-8) and implies that the majority of employment
opportunities would go to people living within the target area.
9.5.10. The figures regarding the potential for local employment generation provided in
this chapter are based on construction industry averages, but the final figures
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achieved will be dependent on the selected contractor’s procurement strategy.
The appointment of the main contractor is subject to a competitive bidding
process and the main plant providers may be based outside the UK or choose to
partner with overseas civil contractors.
9.5.11. Considering the contractor appointment process, a medium level of leakage has
been assumed to reflect the possibility for the appointment of a contractor outside
of the Bristol TTWA. BIS guidance shows that a medium level of leakage is 25%
(Ref. 9-1). A 25% discount has therefore been applied to the estimated 761 jobs
that will be created during the peak year of construction of the Proposed
Development. As a result, it is estimated that 190 persons living outside of the
Bristol TTWA and 571 persons living within the Bristol TTWA would be working
on the Proposed Development during the construction period during the peak
year of construction activity.
9.5.12. The same discount was applied to the 100 short term construction jobs
associated with the construction of the cooling water pipeline. It is estimated that
25 persons living outside of the Bristol TTWA and 75 persons living within the
Bristol TTWA would be working on the cooling water pipeline during its two year
construction period.
Existing Employment
9.5.13. There is no existing construction employment onsite and as such there are no
‘deadweight’ effects that need to be considered in this assessment.
Displacement
9.5.14. Displacement measures the extent to which the benefits of a project are offset by
reductions of output or employment elsewhere. Additional demand for labour
cannot simply be treated as a net benefit as it removes workers from other posts
and the net benefit is reduced to the extent that this displacement occurs.
9.5.15. As described in the baseline, it is estimated that there are 17,200 construction
workers in employment within the study area (Ref. 9-5). The number of
construction workers that would be employed during the peak construction year
of the Proposed Development represents 3.3% of the total construction workforce
in the study area. Construction workers typically move between construction
projects when delays occur or to help the workforce meet particular construction
deadlines. Overall it is assumed that due to the flexibility of the labour market,
and the fact that construction workers at the Proposed Development represent a
small proportion of Bristol’s construction labour force, the displacement effects of
the direct construction employment would be low. BIS guidance shows that a low
level of displacement is considered to be 25% or less (Ref. 9 -2).
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9.5.16. Displacement effects during the peak construction year of the Proposed
Development are equivalent to 190 FTEs, of which 143 would be from within the
Bristol TTWA.
9.5.17. Displacement effects during the construction of the proposed cooling water
pipeline are equivalent to 10 FTEs, of which 7.5 would be from within the Bristol
TTWA.
Multiplier Effects
9.5.18. In addition to the direct construction employment generated by the DCO Site
itself there would be an increase in local employment arising from indirect and
induced effects of the construction activity. Employment growth would arise
locally through manufacturing services and suppliers to the construction process
(indirect or supply linkage multipliers). Additionally, part of the income of the
construction workers and suppliers would be spent in the Bristol TTWA,
generating further employment (induced or income multipliers).
9.5.19. The impact of the multiplier depends on the size of the geographical area that is
being considered, the local supply linkages and income leakage from the area.
The BIS guidance provides a ‘ready reckoner’ of composite multipliers – the
combined effect of indirect and induced multipliers. The guidance suggests that
the majority of projects will have ‘average’ linkages based on the scale of its
economy. Therefore, a composite multiplier of 1.5 has been applied to this
assessment (Ref. 9-2).
9.5.20. Multiplier effects during construction of the Proposed Development are equivalent
to 285.5 FTEs, of which 214 would be from the within the Bristol TTWA.
9.5.21. Multiplier effects during construction of the cooling water pipeline are equivalent
to 15 FTEs, of which 11 would be from within the Bristol TTWA.
9.5.22. The multiplier effects generated by the construction of the Proposed
Development and associated infrastructure are greater than the displacement
effects, meaning that the construction phase would provide a net benefit in local
indirect employment.
Net Construction Employment associated with the Construction Phase
9.5.23. Table 9-6 below summarises the temporary employment estimated to be created
by the Proposed Development and associated infrastructure during construction
(taking leakage, displacement and multiplier effects into account).
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Table 9-6: Net Construction Employment in Bristol TTWA during the Peak Construction Year
Predicted impact
Proposed Development Associated Infrastructure:
Cooling Water Pipeline
Bristol TTWA
Outside Bristol TTWA
Total Bristol TTWA
Outside Bristol TTWA
Total
Gross direct employment
571.0 190.0 761.0 30.0 10.0 40.0
Displacement 143.0 47.5.0 190.0 7.5 2.5 10.0
Net direct employment 428.0 143.0 571.0 22.5 7.5 30.0
Indirect & induced employment
214.0 71.5 285.5 11.0 4.0 15.0
Total net employment during peak construction
642.0 214.0 856.0 34.0 11.0 45.0
Source: URS calculations 2013. Note figures do not always add up due to rounding.*average no. of
construction workers per year
9.5.24. The total net additional construction employment created within the Bristol TTWA
by the Proposed Development in the peak year of construction is estimated to be
642 persons per year, with an additional 214 from outside the Bristol TTWA,
creating a total of 856 FTE jobs during the peak construction period, which is
anticipated to occur in 2019.
9.5.25. The total net additional construction employment created within the Bristol TTWA
from the cooling water pipeline is estimated to be 34 persons and an additional
11 persons from outside the Bristol TTWA, creating a total of 45 FTE jobs over its
one to two year construction period.
9.5.26. In the context of the existing construction labour market in the Bristol TTWA, the
direct, indirect and induced employment and expenditure created by the
temporary construction of the Proposed Development and associated
infrastructure are likely to have a moderate beneficial short-term effect on the
Bristol TTWA economy. This is due to the result of the scale of the construction
workforces in relation to the baseline position, representing 3.9% of the current
workforce.
Operational Employment
9.5.27. The following sections assess the net effect of the Proposed Development in
terms of operation jobs on the Bristol TTWA and South West England
economies.
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9.5.28. The associated infrastructure is not expected to generate any additional
operational jobs. Servicing of the cooling water pipeline is expected to be
performed by existing Wessex Water staff.
Direct Operation Employment
9.5.29. The Proposed Development would generate long-term jobs once it begins
operating, currently expected to be from 2021. The effect of leakage, deadweight,
displacement and multiplier effects, during operation is presented below.
Leakage
9.5.30. The leakage effects of the operational phase of the Proposed Development are
expected to be lower than the leakage associated with the construction phase
because the operational employment will not be contracted in the same way as
the construction process. Analysis carried out on Census 2001 data indicates
that 11.8% of people working in the Bristol TTWA live outside the area (Ref. 9-2).
This represents a ‘low’ level of leakage as set out by BIS (Ref. 9-1) and implies
that the majority of employment opportunities would go to people living within the
target area. This been applied to the operational jobs to reflect the level of
leakage from the Bristol TTWA.
Deadweight
9.5.31. There is no existing operational employment onsite and as such there are no
deadweight effects that need to be considered.
Displacement
9.5.32. The displacement effects of the operational phase of the Proposed Development
are expected to be lower than the displacement associated with the construction
phase. This is because the scale of operational employment and its share of the
local workforce is significantly lower when compared to the construction phase,
and it requires specialist staff. Displacement effects have therefore been
assessed as being low (25%). This is the lowest level of displacement
recommended within BIS Guidance which has been used to calculate the net
employment generated by the operation of the Proposed Development (Ref. 9-1).
Multiplier Effects
9.5.33. In addition to the direct operation employment generated by the Proposed
Development itself there would be an increase in local employment arising from
indirect and induced effects of the operation activity. Employment growth would
arise locally through suppliers to the operation process (indirect or supply linkage
multipliers). Additionally, part of the income of the operation workers and
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suppliers would be spent in the Bristol TTWA, generating further employment
(induced or income multipliers).
9.5.34. A composite multiplier of 1.5 has been applied to the assessment (Ref. 9-1).
Net Operation Employment
9.5.35. The Proposed Development is expected to generate 40 gross FTE jobs during
operation, as outlined in Table 4-2 of Chapter 4: Project Description.
9.5.36. In the event that Seabank Power Ltd chooses to invest in and operate the
Proposed Development in conjunction with Seabank 1 & 2 (and the Applicant
agreed), the number of long term jobs would reduce to an estimated 22 gross
FTE. This is due to efficiency savings, such as the requirement to have less
administrative and security staff if the two generating stations are managed as a
single entity.
9.5.37. The Proposed Development does not currently include any provisions for
management or operation by Seabank Power Ltd, however given that this cannot
be ruled out at this stage and it presents a worse-case scenario for the
operational jobs, it is considered prudent to also assess the effects on this basis,
to avoid inadvertently overestimating the job opportunities onsite.
Direct Operation Employment
9.5.38. Table 9-7 below presents the operational employment figures for both scenarios
(single site management by Seabank Power Ltd or independent management by
the Applicant), taking leakage, displacement and multiplier effects into account.
This includes the net employment onsite and offsite, including growth within
suppliers and external businesses that might benefit from the Proposed
Development.
9.5.39. Assuming a leakage of 11.8% outside the Bristol TTWA, a low level of
displacement at 25%, a 1.5 composite multiplier, and taking into account that
there are no ‘deadweight’ effects, it is estimated that the total net employment for
the Proposed Development under the Seabank Power Ltd operation scenario is
25 employees, of which 22 are from the Bristol TTWA. The total net employment
if operated independently is predicted to be 45 employees, of which 40 would be
expected to be from the TTWA.
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Table 9-7: Net Operation Employment
Predicted impact Single Site Management with Seabank 1 & 2
Independently Managed by SSE
Bristol TTWA
Outside Bristol TTWA
Total Bristol TTWA
Outside Bristol TTWA
Total
Gross direct employment 19.5 2.5 22.0 35.0 5.0 40.0
Displacement 5.0 0.5 5.5 9.0 1.0 10.0
Net direct employment 14.5 2.0 16.5 26.5 3.5 30.0
Indirect & induced employment 7.0 1.0 8.0 13.0 2.0 15.0
Total net employment 22.0 3.0 25.0 40.0 5.0 45.0
Source: URS calculations 2013. Note figures do not always add up due to rounding.
9.5.40. The Proposed Development would displace some existing activity in the local
economy. The loss of expenditure and turnover from existing businesses would
be equivalent to 5 FTEs in the Bristol TTWA and 0.5 FTEs outside the Bristol
TTWA, increasing to 9 and 1 if the site is operated as an independent generating
station. This is the total displacement that is predicted would be caused by the
Proposed Development.
9.5.41. The indirect and induced effects from the Proposed Development would generate
an additional 8 employment opportunities, of which 7 would be created in the
Bristol TTWA. This increases to 15 and 13 if it is operated as an independent
site. As such the Proposed Development would make a positive contribution to
Bristol’s wider economy. The employees generated from multiplier effects are
also greater than the loss of employees from displacement.
9.5.42. The Proposed Development is therefore expected to create around 25 net jobs if
it is integrated with Seabank 1 & 2, and 45 net jobs if operated independently,
against a baseline position of 750 people currently employed within the electricity
and energy generation sector in the TTWA. Therefore, the direct, indirect and
induced employment created by the permanent employment of the Proposed
Development is likely to have a minor beneficial long-term effect on the Bristol
TTWA economy.
Land Use and Public Rights of Way (PROW)
9.5.43. The Proposed Development and associated infrastructure may be visible from
some parts of the PROW during the enabling works and construction period,
which could result in effects in terms of visual amenity. This is discussed further
in Chapter 17: Landscape and Visual Assessment.
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9.5.44. The associated infrastructure related to the Proposed Development includes the
installation of a cooling water pipeline running from Seabank 1 & 2 to Bristol
WWTW. The proposed route of the cooling water pipeline runs across existing
PROWs including the long distance footpath, the Severn Way. It will therefore
cause some disruption to this existing PROW during the construction period.
However, any disruption to footpaths will be planned and notified in advance of
works taking place. Alternative routes will be provided during the construction
period wherever possible and once completed the existing PROW will remain in
their current positions. A temporary diversion will be provided for the Severn
Way.
9.5.45. The Proposed Development includes the provision of a new PROW from Albeton
Lane along the southern boundary of the CCR Site and to the existing
roundabout that lies immediately east of the CCR Site that forms the Spine
Access Road. It is envisaged this PROW would be landscaped and shall provide
footpath and cycle provisions, as well as a grass wayleave for bridleway,
meaning the route will contribute towards the aspirations of the South
Gloucestershire Core Strategy.
9.5.46. The South Gloucestershire Core Strategy recognises the Severnside area as a
strategic employment location and safeguards the Proposed Development Site
and surrounding area for extensive employment uses including energy
generation. Bearing in mind the nature of development being encouraged by the
Core Strategy, it is not considered that the Proposed Development would inhibit
future development of adjacent land.
9.5.47. Overall, the Proposed Development and associated infrastructure is considered
to have a long-term minor beneficial effect on land use and PROW. It is
expected that disruption to PROW will result from the proposed cooling water
pipeline construction but this is only temporary in nature and diversions will be
provided where possible. The provision of a new footpath adds value to the
existing infrastructure by providing a link between the PROWs to the north and
south of the Proposed Development Site, opening up these routes for commuting
and an associated increase in usage.
Leisure and Recreation
9.5.48. The baseline identified that current leisure and recreational usage of the DCO
Site is limited due to the quality of the open space and the relatively long distance
between nearby communities and the Proposed Development. Existing leisure
activity at the Proposed Development Site is expected to be nil currently, as it is
private land. It is therefore anticipated that the Proposed Development and
associated infrastructure will have a negligible effect on leisure and recreational
activity. This is due to the anticipated use and quality of the DCO Site for leisure
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and recreational activity and the available of other sites of similar quality within
the local vicinity.
Tourism
9.5.49. The baseline identified the nearby presence of Blaise Castle Estate a tourism
feature that includes the Blaise Castle Museum and Blaise Hamlet.
9.5.50. Although The Castle Estate is considered to be a tourist attraction of local
importance, the existing character of the DCO Site and the surrounding area
means that the Proposed Development and associated infrastructure is only
considered to have a limited impact on tourism during either construction or
operational phases. This is because the Proposed Development is not expected
to change the view from or setting of the Castle (see Chapter 15: Archaeology
and Heritage and Chapter 17: Landscape and Visual) and is located within an
area that already includes other power generating facilities. The effect is
therefore considered to be a negligible long term effect.
Decommissioning
9.5.51. It is envisaged that the plant will have a design life of 30 years and an operating
life beyond this based on the number of operational hours, and decommissioning
would take approximately one year.
9.5.52. During the decommissioning period, the circa 25-45 net permanent jobs created
by the Proposed Development will be lost. Based on the current scale of the local
and regional workforce employed in electricity, gas, steam and air conditioning
activities, the magnitude of this change is considered to be low.
9.5.53. Based on information provided in the baseline regarding the local labour force in
the study area, it is assessed that the local economy has a low sensitivity to the
loss of jobs in electricity, gas, steam and air conditioning activities. This is
because these jobs contribute a low proportion of employment to the study area’s
total workforce and the size of the operational workforce is small.
9.5.54. Therefore, the decommissioning of the Proposed Development would be likely to
have a minor adverse (not significant) effect on the local economy.
9.5.55. The decommissioning phase will result in uncertain effects on the surrounding
land uses and recreation, due to the timescale of decommissioning. The
decommissioning process will be managed so as to minimise disruption and
change experience by surrounding receptors and resources. Therefore it is
assumed that the effect on these aspects will be negligible.
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Mitigation Measures
9.5.56. To maximise the beneficial impacts for the residents of the district, where it is
within the control of the Applicant, there is an aim to source local labour where
practicable (dependant on skills being available locally). It would be appropriate
for the council to work in collaboration with Job Centre Plus and the Applicant to
identify opportunities for local recruitment.
9.5.57. No adverse effects have been identified and as such no mitigation measures are
required. Saying this, the Applicant will still encourage the sourcing of local
labour through active supply chain engagement. A ‘meet the buyer’ day will be
held where the Engineering, Procurement and Construction (EPC) contractor will
liaise with local businesses and suppliers. The Applicant has also created an
Open4Business (O4B) initiative which provides a dedicated web portal offering
visibility of business opportunities to the local community and suppliers, and
allows the Applicant to advertise contractual opportunities on the portal.
9.6. Residual Effects
9.6.1. It is considered that the Proposed Development and associated infrastructure
would have an overall positive economic effect on the Bristol TTWA economy,
through the provision of employment and through associated multiplier effects.
9.6.2. The construction of the Proposed Development would make a positive
contribution to the Bristol TTWA’s economy with 856 net employees expected to
be generated during the peak year of construction activity, of which 642 would be
from the Bristol TTWA. The construction of the cooling water pipeline is expected
to generate an additional 100 net FTE jobs, of which 75 would be in the Bristol
TTWA economy.
9.6.3. The operation of the Proposed Development would make a positive contribution
to the Bristol TTWA’s economy with between 25 and 45 net employees expected
to be generated on and offsite (depending on whether it is operated as a single
site or with Seabank 1 & 2). Of these net employees, the majority is expected to
be from the Bristol TTWA.
9.6.4. The Proposed Development would have a beneficial effect on the Bristol TTWA
economy, through employment opportunities and supply chain benefits to local
businesses. The Proposed Development will also provide additional social
benefits such as the provision of a new PROW.
9.6.5. A summary of the residual socio-economic effects of the Proposed Development
and associated infrastructure is provided in Table 9-8 below.
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Table 9-8: Summary of Residual Effects
Aspect Duration and extent Significance
Employment generation during the construction phase (direct, indirect and induced effects)
Short term; Regional Moderate beneficial
Employment generation during the operational phase
Long term; Regional Minor beneficial
Land use and PROW Long term; Local Minor beneficial
Leisure, Recreation and Tourism
Long term; Local Negligible
Decommissioning Long term; Regional Minor adverse for employment
Negligible for land use, PROW and tourism
9.6.6. As mentioned in the Assessment Methodology section above, the assessment
has been based on the maximum design parameters for the Proposed
Development. It is feasible that the effects may have been overestimated if the
Proposed Development is not built out in full, however this is not expected to
change the level of significance that has been assigned to the residual effects.
9.7. Cumulative Effects
9.7.1. This section assesses the effect of the Proposed Development and associated
infrastructure in combination with the likely effect on the local economy arising
from other developments in the area, as outlined in Chapter 7: Assessment
Methodology.
9.7.2. Table 9-9 lists the cumulative schemes that are either similar in nature or scale to
the Proposed Development or sufficiently close to potentially lead to cumulative
effects. Existing schemes such as Seabank 1 & 2 form part of the baseline and
hence have not been discussed in this section.
Table 9-9: Summary of Schemes Relevant to Cumulative Socio-Economic Effects
Scheme Gross Construction
jobs
Gross Operation jobs
SITA Bottom Ash Facility, Severnside Energy Recovery Centre, Severn Road
200 9
Development of the Severnside Energy Recovery Centre, SITA
Data not provided in the ES
Data not provided in the ES
Helius Energy biomass fuel store and generating plant, Avonmouth Docks
264 40
E.On Climate & Renewables UK Developments Ltd biomass-fired renewable energy plant, Royal Portbury
300 40
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Scheme Gross Construction
jobs
Gross Operation jobs
Dock
Viridor Resource Recovery Centre 200 65
Total 964 171
9.7.3. The above schemes are expected to create an additional 964 construction jobs
and 171 operational jobs, excluding the employment impact of Severnside
Energy Recovery centre for which information is not currently available from its
EIA. Other cumulative developments are presented in Chapter 7: Assessment
Methodology but have not been considered due to their distance from the DCO
Site, scale, or because they are at a preliminary stage of planning (for example
the proposed Avon Power Station).
9.7.4. When combined with the construction jobs resulting from the Proposed
Development and associated infrastructure, there would be a total of
approximately 1,865 short-term construction jobs. Based on the size of the
existing construction workforce in the study area the short-term cumulative
construction jobs would represent approximately 10.8% of this workforce.
Therefore the cumulative construction activities would have a moderate
beneficial effect on the Bristol TTWA and South West economy.
9.7.5. The operational jobs associated with the Proposed Development and the
operational jobs associated with the cumulative developments would create
approximately 196-216 jobs. Considering the size of the existing workforce in the
study area as presented in the baseline, the combined effect of the Proposed
Development with the cumulative schemes in terms of operational jobs would
create a moderate beneficial effect on the Bristol TTWA and South West
economy.
9.7.6. Given the absence of any adverse land use, recreation and leisure, and tourism
effects associated with the Proposed Development, it has not need deemed
necessary to assess the potential cumulative effects associated with these
aspects – any significant cumulative effects would be due to these other
schemes rather than the Proposed Development.
9.8. Impacts and Effects yet to be Determined
9.8.1. There are no impacts and effects yet to be determined, however, the scheme
design may be subject to change prior to submission of the final DCO application.
Any changes that lead to differing or new impacts and effects will be highlighted
within the final ES, along with the reasons for the change.
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9.8.2. It is also possible that the baseline conditions will change between the
preparation of this PEI Report and the final ES; land use, recreation and socio-
economic conditions are dynamic and evolve over time. The Proposed
Development Site is currently subject to excavation, top soil stripping, and
levelling in certain areas in order for third parties to deliver the Spine Access
Road and new channel for the Red Rhine, which are discussed in Chapter 2: The
DCO and EIA Process and Chapter 7: Assessment Methodology. A haul road is
also being constructed through the middle of the Proposed Development Site to
enable access by third party from the roundabout to the east of the Site to the
Severnside Energy Recovery Centre to the west. These works onsite are being
undertaken by other developers, under extant planning permissions and are
separate to the Proposed Development.
9.8.3. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changes
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
9.9. References
Ref. 9-1 Department for Business, Innovation and Skills (BIS), 2009: Research to Improve the Assessment of Additionality.
Ref. 9-2 Census, 2001: Travel to Work Areas.
Ref. 9-3 Office for National Statistics (ONS), 2013; Mid-Year Population Estimate 2012.
Ref. 9-4 ONS, 2013: Annual Population Survey, 2013.
Ref. 9-5 ONS, 2013: Business Register and Employment Survey (BRES) 2012.
Ref. 9-6 WYG and Amion Consulting, 2012 Avonmouth and Severnside Outline Development Strategy, 2012.
Ref. 9-7 UK Tourism Survey and International Passenger Survey (2010). South West of England Regional Summary. Visit England.
Ref. 9-8 Bristol Parks. A Management Plan for Blaise Castle Estate. 2008-2013. Bristol City Council.
Ref. 9-9 Visit England, 2010: Accessed November 2013: www.visitengland.org.
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10. Traffic and Transport
10.1. Introduction
10.1.1. This chapter of the PEI Report assesses the effect of the Proposed Development
and associated infrastructure on the surrounding highway network, public
transport, and local pedestrian and cyclist amenity. It is based on an assessment
of the interaction between future development related movements and existing
patterns of vehicular movements.
10.1.2. It sets out relevant Government policy at national and local level, which has been
considered in respect of the Proposed Development and associated
infrastructure. A description of the baseline conditions is provided, along with
details of the assessment methodology and significance criteria that have been
used to assess the potential effects.
10.1.3. The following effects on users of local roads and the occupiers and users of land
that front the roads have been assessed in this chapter in the following order:
• Severence;
• Driver delay;
• Pedestrian and cyclist delay;
• Pedestrian and cycle amenity;
• Public transport;
• Fear and intimidation; and
• Accidents and safety.
10.1.4. The traffic and transportation assessment is detailed further in a Transport
Assessment (TA), which is presented in Appendix E, Volume II of this PEI Report
and summarised in this chapter.
10.1.5. It has been agreed that a Construction Traffic Management Plan (CTMP) and a
construction workers’ Travel Plan will also be appended to the final ES, although
these have not been prepared as part of this PEI Report, as they will be finalised
following feedback received during the formal consultation process.
Consultation
10.1.6. Table 10-1 summarises the comments received from the HA, SGC and BCC in
their Scoping Responses and following their receipt of the URS ‘Trip Generation
and Distribution report’, which provided additional information on the proposed
methodology and approach for the TA (and which is an annex to the TA for
reference).
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Table 10-1: Summary of Stakeholders Comments on Traffic and Transport
Consultee Key Issues / Comments Raised Location of Information in Chapter
BCC
The Applicant should consider the effect along the A403 from the Proposed Development Site to the M5, junction 18 including roundabouts.
This road link has been included in the TA and this chapter.
Methods of transport should be investigated for bringing materials to the Proposed Development Site, including rail or port.
See sections 10.3 and 10.5 of this chapter
Details of abnormal loads should be provided, as well as a before and after survey of the A403 in the vicinity of the Proposed Development Site in case it is damaged by the construction.
See sections 10.3 and 10.5 of this chapter for information on abnormal loads.
Before and after surveys will be discussed in the CTMP, which will be available as part of the final ES.
SGC The approach proposed is considered acceptable subject to including reference to relevant policies in the South Gloucestershire Local Plan and Core Strategy.
Reference to these policies is included in the TA.
The proposed development affects several promoted recreational routes identified under saved Local Plan policy LC12 Bridleway / Multiuser links.
Attention is required to the part of Ableton Lane that runs around the perimeter of the scrap yard by horses to reach the Minors Lane bridleway.
See section 10.6 of this chapter
Consideration should be given to other significant civil projects in the area that may have a bearing on the availability of workers, such as Hinckley Point and Oldbury Power Station.
See section 10.7.
Consideration within the TA should be made for materials to be brought to the site via rail and hence reducing the impact on the local highway network.
See section 10.5 of this chapter
Consideration must be given to the local public rights of way for commuting.
See section 10.5 of this chapter
A Travel Plan aiming to promote sustainable journeys, outlining all mitigation measures to the site is required. In addition to the Travel Plan, a Construction Traffic Management Plan is required.
Both a Travel Plan and a Construction Travel Plan will be submitted as part of the DCO application with the final ES.
HA Detailed information on staffing numbers, mode share, shift patterns, HGV numbers, HGV arrival/departure profiles, development phases, and Abnormal Indivisible Loads, should be determined at the earliest opportunity [for the construction phase].
See section 10.5 of this chapter and the TA.
The potential for cumulative impact with the potential Avon Power Station should be considered.
See section 10.7 of this chapter
Planning Inspectorate
The ES should consider potential impacts on the local footpaths and any PROW.
See section 10.5 of this chapter
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Consultee Key Issues / Comments Raised Location of Information in Chapter
Potential transport impacts resulting from waste to be removed from the Site during construction should be addressed
See section 10.5 of this chapter
As the delivery of the proposed new spine road is outside the control of the Applicant the ES should include an assessment of potential impacts should it not come forward as planned
See section 10.5 of this chapter
10.1.7. Following receipt of the Scoping Opinion, a series of informal meetings were held
with SGC, BCC and HA in which it has been agreed that the construction phase
is the most critical phase of the development and the effects of the operational
phase may be scoped out of detailed further assessment.
10.1.8. This was agreed on the basis that once the Proposed Development is in
operation, it is estimated that up to a maximum of 40 workers will be present on
Site, which could be reduced to 22 new workers if the Proposed Development is
managed collaboratively alongside Seabank 1 & 2. A total of three shifts would
be in place resulting in an estimated maximum of 13 workers onsite at any one
time, including peak hours. Traffic associated with maintenance and deliveries (of
distillate fuel for example) will be minimal, with up to a maximum 24 two way daily
movements (12 deliveries) expected following a black start event; this is
expected to be an abnormal, infrequent event (e.g. once per annum).
Legislation and Planning Policy Context
10.1.9. There is no legislation or regulations specifically related to traffic and transport.
10.1.10. An overview of the national and local planning policy relevant to this assessment
is provided in the TA, Appendix E, Volume II of this PEI Report, as well as
Appendix D to Chapter 8: Planning Policy Context.
10.2. Assessment Methodology and Significance Criteria
Assessment Methodology
10.2.1. This assessment has been undertaken in accordance with the guidance provided
in the 1993 Institute of Environmental Assessment (IEA) publication Guidance
Notes No. 1: Guidelines for the Environmental Assessment of Road Traffic (Ref.
10-1), hereafter known as the IEMA guidelines.
10.2.2. The following categories of receptors that may be sensitive to changes in
numbers of people movements (sensitive receptors) have been identified:
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• Severence - Severance is the perceived division that can occur within a
community when it becomes separated by a major traffic artery;
• Driver delay - Delays to non-development traffic can occur on the
network due to the additional traffic generated during site enabling and
construction;
• Pedestrian and cyclist delay - Changes in the volume, composition or
speed of traffic may affect the ability of people to cross roads and
therefore lead to greater increases in delay;
• Pedestrian and cycle amenity - Pedestrian and cyclist amenity is defined
as the relative pleasantness of a journey and is considered to be affected
by traffic flow, traffic composition and footway width/separation from
traffic;
• Public transport – The availability of public transport facilities and their
capacity in the area surrounding the Proposed Development Site;
• Fear and intimidation - The scale of fear and intimidation experienced by
pedestrians and cyclists is dependent on the volume of traffic, its HGV
composition, its proximity to people or the lack of protection caused by
factors such as narrow pavement widths; and
• Accidents and safety – The safety of the area is assessed by reviewing
the number of accidents taken place in the area as well as their nature.
10.2.3. The methodology for the TA which this chapter is based on has been agreed with
SGC, BCC and the HA and is outlined below.
Study Area and Data Sources
10.2.4. The scale and extent of the assessment has been defined whilst developing a
gravity model. The gravity model is a model which calculates the relationships
between two places, in this case between workers’ homes and the Proposed
Development Site, depending on travel distance, time and costs. The model has
been used to identify predicted construction workers’ journeys to and from the
Proposed Development Site. The geographical extent of the assessment is
illustrated in Figure 10-1 (Volume III of this PEI Report).
10.2.5. In order to establish traffic volumes on the local network, traffic surveys have
been undertaken. Two separate traffic count surveys were commissioned on the
A403 in November 2013. The details for these surveys are set out below and
also illustrated on Figure 10-1 (Volume III of this PEI Report):
• An Automatic Traffic Count (ATC) located on the A403 just north of the
entrance to the existing Seabank 1 & 2 site. Data was recorded for seven
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days between Thursday 14 November and Wednesday 20 November
2013 (see Location 1 on Figure 10-1, Volume III of this PEI Report); and
• A classified traffic turning count survey at the junction Severn Road /
A403 / Chittening Road undertaken on Wednesday 14 November 2013 for
24 hours (see Location 2 on Figure 10-1, Volume III of this PEI Report).
10.2.6. A range of other existing traffic count data sources have been interrogated to
establish the baseline traffic in the surrounding area. In addition to the locations
where surveys were commissioned in November 2013, previous surveys have
also been completed at the locations set out below:
• Avonmouth Way / McLaren Road / King Road / A403 - Traffic counts
taken from the TA for the Viridor Resource Recovery Centre (Ref. 10-2)
by K&M on 24 February 2009 (see Location 3 on Figure 10-1, Volume III
of this PEI Report);
• A403 (near junction with B4064) towards the junctions with M48 – Data
derived from the Department for Transport’s (DfT’s) traffic count database
2012 (Ref. 10-3) (see Location 4 on Figure 10-1, Volume III of this PEI
Report); and
• Almondsbury Interchange Movement: (westbound), M4/M5, M4
(westbound) Slip to M5 (northbound – data derived from TRADS 2009
(Ref. 10-4) (see Location 5 on Figure 10-1, Volume III of this PEI Report).
10.2.7. The locations set out in Figure 10-1 (Volume III of this PEI Report) have been
selected for assessment. The criteria used for selecting these locations for
assessment is set out below.
• Locations 1 and 2: These survey locations have been selected because
they are close to the DCO Site and on the A403 which is expected to be
used by the construction traffic associated with the Proposed
Development and associated infrastructure ;
• Location 3: Based on the results of the trip distribution analysis it is
predicted that approximately 50-60% of construction workers are
expected to access the DCO Site from the north on the A403.
Consequently this location was included; and
• Locations 4 and 5: The HA, SGC and BCC advised that there may be
limited spare peak hour capacity at the Almondsbury Interchange
(M4/M5), as well as the junctions linking the A403 to the A4 and the M5.
These are junctions with high volumes of traffic, in particular during peak
hours. Location 4 and 5 have therefore been included in the assessment.
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Estimated Construction Worker Numbers
10.2.8. To determine the number of construction workers expected to be required
throughout the construction phase, site specific construction requirements have
been estimated by a specialist potential contractor (who will be one of several
contractors that will be invited to tender for the construction works).
10.2.9. An example of the full construction schedule with associated activities is
presented in Table 5-1 in Chapter 5: Enabling Works and Construction. While this
schedule is inevitably only indicative at this stage, it nevertheless is based on
lessons learned from equivalent CCGT construction projects and therefore is
considered representative of the sort of construction programme that is likely to
occur. The numbers presented in the programme are considered to represent the
worst-case estimates of construction personnel accessing the Site, as it assumes
the Proposed Development would be built in a single phase, and the
assessments presented in this Chapter are therefore based on conservative
estimates.
10.2.10. Based on this information it is currently expected that the peak daily traffic
generation would occur in 2019, when an average of 790 staff may be accessing
the site daily. It was agreed with SGC, BCC and the HA that the expected peak
construction month should be the focus of the assessment.
10.2.11. It is the Applicant’s intention that the Order will allow a 7 year time period in
which to start construction after receipt of the DCO. The peak construction year
may therefore theoretically occur anywhere between 2017 and 2024. Given that
the majority of the cumulative schemes identified in Chapter 7: Assessment
Methodology are expected to be built and operational by 2017 (with the likely
exception of the Hinkey C Connection project and Avon Power Station), it is not
expected that the assessment of 2019 conditions is a limitation to the
assessment, or that a delay to the start of construction would affect the potential
effects or mitigation measures identified in this assessment.
10.2.12. For the future (2019) baseline, it has not been possible to determine the trip
distribution of all the cumulative schemes listed in Chapter 7: Assessment
Methodology from relevant Transport Assessments and their effect on various
junctions / road sections (the cumulative schemes are discussed further in the
last section of this chapter ‘Cumulative Effects Assessment’). To account for this,
relevant growth rates from the traffic model used in the assessment (TEMPro1)
has been applied to all baseline traffic data to forecast traffic flows for 2019. This
1 TEMPro (Trip End Model Presentation Program) is a software developed by the Department for Transport
and is used for transport planning purposes. The forecasts include population, employment, households by car
ownership, trip ends and simple traffic growth factors based on data from the National Transport Model (NTM).
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will result in some double counting but it is considered a robust assumption for
this assessment.
10.2.13. As discussed in Chapter 7: Assessment Methodology, it is envisaged that the
proposed Spine Access Road will be available for use by the time the Proposed
Development is starting to be constructed; its construction is currently underway
and it is forecast for completion in early 2015. However, for the purposes of
presenting a conservative assessment of potential effects, this assessment has
been undertaken without including the benefits associated with this Spine Access
Road (which could relieve pressure on the A403).
10.2.14. It is therefore considered that an assessment of 2019 conditions without the
Spine Access Road represents a robust assessment for the purposes of this PEI
Report.
Significance Criteria
10.2.15. The significance of each effect is considered against the criteria within the IEMA
guidelines where possible. This guideline states that:
“for many effects there are no simple rules or formulae which define the
thresholds of significance and there is, therefore, a need for interpretation and
judgement on the part of the assessor, backed-up by data or quantified
information wherever possible. Such judgements will include the assessment
of the numbers of people experiencing a change in environmental impact as
well as the assessment of the damage to various natural resources.”
(paragraph 4.5)
10.2.16. According to the IEMA guidance, significance falls into two categories: not
significant and significant. The latter corresponds to likely significant effects in
accordance with the EIA regulations (and for the purpose of this PEI Report has
been assumed to correspond with moderate and major effects).
10.2.17. In the absence of established significance criteria for traffic and transport effects,
professional judgement has been used to assess whether the effects on traffic
and transport are considered to be significant, using the IEMA guidelines to
identify the scale and extent of the assessment to be undertaken.
10.2.18. The following rules are provided in the IEMA guidelines as a screening process
to define the scale and extent of a potential effect:
• Rule 1: Include roads where traffic flows are predicted to increase by
more than 30% (or where the numbers of HGVs are predicted to increase
by more than 30%); and
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• Rule 2: Include any specifically sensitive areas (such as junctions with
limited capacity and residential areas) where traffic flows are predicted to
increase by 10% or more, or an absolute increase of 30 or more vehicles,
as defined by the HA. It should therefore be assumed that projected
changes in traffic of less than 10% or 30 vehicles create no discernible
environmental effect.
10.2.19. The IEMA guidelines elaborates on Rule 1 stating that projected changes in
traffic of less than 10% create no discernible environmental impact, given that
daily variations in background traffic flow may fluctuate by this amount, and that a
30% change in traffic flow represents a reasonable threshold for including a
highway link within the assessment.
10.2.20. This guidance is the only published guidance document to set out a methodology
for assessing potentially significant traffic-related environmental effects where a
proposed development is likely to give rise to changes in traffic flows.
10.2.21. After taking into consideration any mitigation measures, residual effects have
been identified as either:
• Adverse – meaning that they produce negative effects to transportation
and access;
• Negligible – meaning that there is no measurable effect; or
• Beneficial – meaning that they produce benefits in terms of transportation
and access.
10.2.22. Where adverse or beneficial effects have been identified these have been
assessed against the following scale:
• Minor – slight, very short or highly localised effect of no significant
consequence;
• Moderate – limited effect (by extent, duration or magnitude) which may be
considered significant; and
• Major – considerable effect (by extent, duration or magnitude) of more
than local significance or in breach of recognised acceptability, legislation,
policy or standards.
Key Parameters for Assessment
10.2.23. This assessment employs the ‘Rochdale Envelope’ approach (as detailed in the
Planning Inspectorate Advice Note 9) and described in Chapter 2: The DCO and
EIA Process.
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10.2.24. The variation in building dimensions presented in Chapter 4: Project Description
under the Rochdale Envelope principle is an important consideration for this PEI
Report. However, in order to ensure a robust assessment has been undertaken,
the maximum parameters have been assessed. This includes the assumption
that the site levels will be raised up to the maximum 8.5m AOD, and that the
Proposed Development would be built in a single phase, which would compress
the construction worker numbers into a shorter time frame.
10.2.25. It is not considered that the flexibility in building location or heights and footprints
would have a material effect on the assessment.
10.2.26. It is intended the DCO Application will enable construction to start within 7 years
of receipt of the DCO. 2019 has been assessed for the peak construction year,
with 2021 as the year of first operation. As explained above, it is not expected
that a delay in the start date of construction would significantly affect the findings
of this assessment.
10.3. Baseline Conditions
Local Road Network
10.3.1. The A403 Severn Road is the main route to the Proposed Development Site and
provides connections with the wider road network. It is a single lane carriageway
that runs from Avonmouth to the south of the proposed Development Site to a
junction with the M48 motorway in the north, located on the east side of the
Severn Bridge. To the south of the Proposed Development Site, the A403 links to
the A4 which continues towards the west and central Bristol, and also provides
access to Junctions 18 and 18a on the M5 and M49.
10.3.2. Due to the industrial nature of the surrounding area, the road network is designed
for HGV use. The speed limit on the A403 is mainly 50 miles per hour.
10.3.3. Based on discussions with the HA, SGC, and BCC, potentially sensitive areas on
the road network that may already experience high volumes of baseline traffic
include the roundabouts connecting the A403 with the A4 and the motorway
network, as well as the Almondsbury Interchange which connects the M4 with the
M5. It is understood that delays on these junctions could have a significant effect
on the surrounding road network.
Railway Services
10.3.4. The nearest railway station is Severn Beach train station which is located
approximately 2.7km from the Proposed Development Site, accessed via the
A403 Severn Road to the north. Services at Severn Beach are all terminating
services from Bristol Temple Meads. The journey between Severn Beach station
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and Bristol Temple Meads is approximately 40 minutes and the frequency of the
train service is two trains between 0700 and 0800 in the morning and then one
train every two hours throughout the day.
10.3.5. A more frequent service is provided from Avonmouth Station, with services every
30 minutes during peak hours of the day. This station is further from the
Proposed Development Site, located approximately 6km to the south and just off
the A403 (St. Andrew’s Road).
10.3.6. The local trains accommodate spaces for bicycles, although some can only
accommodate two bicycles, on a first come first served basis.
10.3.7. The railway stations have limited facilities but are covered by CCTV and both
stations have access to a bus stop outside the station.
Local Bus Services
10.3.8. The bus stop nearest to the Proposed Development Site is located where Severn
Road meets with Ableton Lane in Severn Beach, approximately 2km north of the
entrance to the Proposed Development Site. The bus stop is served by route 625
and provides hourly services to University of West of England (UWE) via Easter
Compton, Cribbs Causeway, Patchway and Bristol Parkway in the southeast
direction, and to Severn Beach Station which is located further along the road in
the north direction. An extensive local and regional bus network can be reached
from Cribbs Causeway bus terminal.
10.3.9. Bus services are also provided from Avonmouth railway station, providing
connections to Shirehampton and Bristol City Centre (Route 41) every 20
minutes.
Walking and Cycling
10.3.10. Footways exist along the eastern side of the A403, for some sections. No street
lighting is provided along the Severn Road section of the A403. Due to the
distances between local transport facilities / residential areas and the Proposed
Development Site, the proportion of staff expected to walk to work in the local
area is not likely to be significant.
10.3.11. National Cycle Network route 41 runs adjacent to the A403, extending towards
Severn Village in the north and towards Avonmouth, Hallen and central Bristol in
the south.
10.3.12. The area of Severnside/ Avonmouth is well covered by public rights of ways,
footpaths, bridleways and byways, as shown in Figure 3-5, Volume III of this PEI
Report.
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Site Access
10.3.13. This section discusses the existing access arrangements to the Proposed
Development Site and future baseline conditions, which assume the Spine
Access Road is in place.
10.3.14. These construction access points are illustrated in Figure 5-3, Volume III of this
PEI Report.
10.3.15. During construction a total of four access points may be utilised, although two of
these would not be available if the Spine Access Road is not built. The first
access point is located in the southeast corner of the Proposed Development
Site, from the existing roundabout that lies immediately east of the Site. An
additional two access points will be located further along the proposed Spine
Access Road that will link the aforementioned roundabout with the A403. A forth
access/egress point is along Ableton Lane, although this would be a secondary
access point and unlikely to be used by HGVs.
10.3.16. The access points for the operational Proposed Development are illustrated in
Figure 4-7, Volume III of this PEI Report.
10.3.17. The primary access point to the operational Site will be from the Spine Access
Road which is located immediately north of the Proposed Development Site, near
the eastern end of the Generating Station Site.
10.3.18. A secondary access point is proposed from the Seabank 1 & 2 site via an
entrance in the northwest corner of the Proposed Development Site. This access
will be used during operation to link the two sites, but would also act as a ‘back
up’ entrance should any issues occur with the Spine Access Road which is
currently not completed.
10.3.19. An additional secondary access point may also be included from Ableton Lane,
although it is not intended that this would be a main access point. It is likely that
this would be maintained for pedestrian access/egress and emergency vehicles.
Baseline Traffic flows
10.3.20. A summary of the traffic count results is provided in Plate 10-1 and Plate 10-2 for
the two traffic counts undertaken in November 2013. Plate 10-1 presents the
results for daily traffic flows on an average weekday and Plate 10-2 presents the
daily results for an average weekend.
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Plate 10-1: Average Weekday Automatic Traffic Counts Results on the A403
10.3.21. There are pronounced peak hours during 07:00-08:00 and 17:00-18:00 during
the average weekday on the A403. HGV movements are generally consistent
throughout the day at approximately 100, with a slight increase between 07:00
and 17:00, peaking between 16:00-17:00.
Plate 10-2: Average Weekend Automatic Traffic Counts Results on the A403
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10.3.22. Plate 10-2 shows a much lower volume and peak in traffic flows during the
weekends than weekdays. The weekend peak is approximately 300 vehicles,
occurring between 12:00 and 13:00. HGV movements remain at approximately
30 throughout the day.
10.3.23. Plate 10-3 illustrates the figures for daily flows on the junctions A403 / Severn
Road (A403) / Chittening Road on Wednesday 14 November 2013.
Plate 10-3: Traffic Counts Results at the Junction of Severn Road / A403 / Chittening
Road on Wednesday 14 November 2013
10.3.24. There are pronounced peak hours on the A403 at the Chittening Road junction
during the AM and PM peak periods of 07:00-09:00 and 17:00-18:00. HGV
movements are generally consistent throughout the day, ranging from
approximately 150 to 200, with its peak between 15:00-16:00. Turning counts
were not undertaken during weekends at this junction. However the results from
the ATC show that the volumes of traffic on the A403 are significantly less during
weekends.
Personal Injury Accidents
10.3.25. Personal Injury Accidents (PIAs) are road traffic accidents where either slight,
serious or fatal injuries to people have been recorded. The data includes
information such as the location of the accident, number of casualties, the modes
of travel involved, age and gender of those involved and the factors contributing
to the accident.
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10.3.26. Data has been collected for the most recent five year period, 01 May 2008 to 30
April 2013 from BCC and SGC. Table 10-2 summaries the accidents at the key
road sections / junctions in the area. The reported incidents are of a type and
quantity that would be expected over a 5 year period, and notably only eight
incidents involved HGVs across the selected road sections / junctions. The
majority of accidents occurred at the Almondsbury Interchange.
10.3.27. A detailed review of the accident descriptions has taken place (additional
information is provided in the TA, Appendix E, Volume II of this PEI Report) and
all accidents have been results of driver error rather than any inherent highway
design issues.
Table 10-2: Personal Injury Accident Data (01 May 2008 to 30 April 2013)
Road Section / Junction Severity – Slight
Severity - Serious
Severity –
Fatal
Number of total
accidents
Including HGVs / LGVs
involved
A403 – between junction with Avonmouth Way (A4) and boarder with SGC
24 3 1 28 0
A403 – between boarder with BCC and junction with the M48
5 1 0 6 0
A403 intersecting with Avonmouth Road
4 2 0 6 0
A403 intersecting with Avonmouth Way
4 0 1 5 0
A403 intersecting with St Andrews Road
1 1 0 2 1 LGV
M49 / M5 8 2 0 10 0
Junction M48 / A403 4 1 0 5 0
Section between Almondsbury Interchange and junction M48 / A403
8 2 0 10
2 LGVs (Slight)
1 HGV (Serious)
Almondsbury Interchange 38 6 0 44 1 LGV (Slight)
7 HGVs (Slight)
10.4. Development Design and Impact Avoidance
10.4.1. There are no specific avoidance measures that have been implemented in the
design of the completed Proposed Development relevant to traffic and transport.
Chapter 5: Enabling Works and Construction does however note that the location
of the contractor compound is on the CCR Site, with the contractor parking
closest to the existing roundabout immediately east of the Proposed
Development Site.
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10.4.2. The scheduled period of land raising has been determined based on preliminary
modelling, to derive the minimum acceptable period whilst avoiding significant
impacts to traffic and transport, air quality, and noise. It has been assumed that
the land raising period would be undertaken over a period of six months; this has
been calculated based on the maximum number of vehicle movements needed to
raise the site to 8.5m AOD distributed over the shortest time period deemed not
cause a significant impact. In reality, the land raising may be extended over a
longer period of time, which would reduce the effect on traffic and transport,
however it was considered prudent to present the worst-case scenario in this
assessment, which is considered to be 6 months.
10.5. Potential Effects and Mitigation Measures
Assessment of Construction Effects
10.5.1. The main construction activities include the site preparation and enabling works
phase and the construction of the Proposed Development; these activities are
discussed below.
Enabling Works
10.5.2. Chapter 13: Flood Risk, Hydrology and Water Resources of this PEI Report
identifies the need to raise the finished floor levels of the structures within the
Generating Station Site by an average of approximately 2.2m, from an average
current level of 6.3m AOD to a maximum 8.5m AOD.
10.5.3. To raise this land to a maximum 8.5m AOD, an estimated 158,000m3 of material
is required, which needs to be brought into the Proposed Development Site.
10.5.4. In reality, the amount of fill required may be up to 30% less than this, should the
cooling water system be bunded rather than raised for example, and when
allowing for a foundation sub-base for buildings. For the purpose of this
assessment however it has been considered robust to use the calculated
maximum value of 158,000m3.
10.5.5. The opportunities available to bring some of the material to Site by rail will be
explored by the Applicant following granting of the DCO, however it is not
currently considered viable. This is because access to rail facilities at the Site is
dependent on a third party development which has not yet proceeded (Ref. 10-5),
as well as it being unfeasible to extend the line into the Site for the construction
period only. For the purposes of the assessment presented in this PEI report
therefore, and to ensure a worst-case assessment of potential traffic impacts is
presented, it has been assumed that all material deliveries will be made by road.
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10.5.6. Furthermore, there may be an opportunity to transport material via the
Avonmouth Port, although this would be subject to further discussions with the
port authority and the chosen contractor. In any event, any such material
imported through the port would have to be offloaded on to HGVs for
transportation to Site and these HGVs would have to travel via the A403. No
discussions with the Port Authority have therefore taken place at this stage, and
by assuming 100% road use at this stage, it should represent the worst case
scenario.
10.5.7. Until the Proposed Development has a DCO and the Applicant further
discussions with Contractors, it is not known where material for land raising will
be sourced from; it is considered most likely that material will be sourced from
local quarries. The nearest quarry with potentially suitable aggregates is
Stancombe Quarry in Flax Bourton, which would be accessed from the A370
south of Bristol via the A4 (Portway).
10.5.8. For the purpose of this assessment it is assumed that all HGVs delivering fill
would access the A403 from the A4 Portway. This is because the junctions
connecting the A403 with the A4 (Portway) and the motorway network have been
identified by the HA as potentially more sensitive than the junctions north of the
Proposed Development Site; hence this assumption is considered to represent
the worst-case scenario for the purposes of this PEI Report. Sensitivity tests have
been undertaken to assess the effect should this traffic be routed via other
directions.
10.5.9. In order to provide a robust assessment the assessment has been based on the
assumption that all deliveries would be 10m3 capacity HGVs. This would result in
up to 15,800 HGV deliveries being required to raise the Generating Station Site
to the maximum 8.5m AOD. In practice, it is expected that each HGV delivery
could transport 15m3 or more of top soil if using larger HGVs, which could in
practice reduce the number of deliveries required by around 5,300 HGVs.
10.5.10. As mentioned above, it has been assumed that the land raising period would be
undertaken over a period of six months and that work would be undertaken on
weekdays only and between 0700 and 1900 hours. The DCO Application
includes 24 hour deliveries, 7 days a week, and therefore in reality night-time and
weekend deliveries will be allowed which would reduce the pressure on the
daytime periods during weekdays. For robustness however, and in case the
Contractor chooses to avoid weekends and night-time delivers, it is assumed that
deliveries would be on weekdays only which would result in approximately 130
deliveries, or 260 two-way daily movements per day over the six month period.
10.5.11. Furthermore, in order to deliver a robust assessment that does not inadvertently
constrain the Contractor, it has been assumed that the material would be brought
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in during a 10 hour period. On average over a 10 hour day, the daily two-way
movements would be approximately 26 movements per hour. As requested by
the HA, measures and/or commitments will be introduced to reduce the effect on
the highway network, such as limiting the number of deliveries during peak hours
and making use of areas within the Proposed Development Site to stockpile
material to avoid deliveries during holiday periods (when local road traffic flows
generally are higher). These measures will be detailed further in the CTMP,
which will be appended to the final ES.
10.5.12. During the enabling works it is assumed that up to 30 workers may access the
site daily. Some trips associated with these workers may occur during peak hours
although it is expected that the shift times would start and finish outside of the
peak hours identified above (0600 or 0700 start, 1900 finish).
10.5.13. An analysis of the potential change in traffic flows on the A403 at the junction
with Chittening Road / Severn Road (Location 2 on Figure 10-1, Volume III of this
PEI Report) and the signalised roundabout (Avonmouth Way / McLaren Road /
King Road / A403, (Location 3 on Figure 10-1, Volume III) is provided in Table
10-3. All traffic associated with the Proposed Development is assumed to pass
through both these locations, despite this being an unrealistic overestimate, in
order to present a conservative assessment as outlined above.
10.5.14. The results are presented for the peak hours prior to any HGV mitigation for both
junctions as well as daily flows for the A403 / Severn Road / Chittening Road
junction. Daily flows are not provided for the Avonmouth Way / McLaren Road /
King Road / A403 junction. Trips associated with the workers accessing the
Proposed Development Site during this phase have been excluded in the
assessment due to the low number discussed above.
Table 10-3: Traffic Increase during Land Raising Works Prior to Additional Mitigation
Location Time period
2019 Base Flows (Growthed to
include cumulative schemes)
Proposed Development Flows
during Land Raising (prior to
mitigation)
% increase (prior to mitigation)
Total Vehicles
HGVs Total
Vehicles HGVs
Total Vehicles
HGVs
A403 / Severn Road / Chittering Road
(Location 2 on Figure 10-1 (Volume III)
AM Peak
(0800-0900) 437 124 26 26 6% 21%
PM Peak
(1700-1800) 371 115 26 26 7% 23%
Daily 11,128 2,927 260 260 2% 9%
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Location Time period
2019 Base Flows (Growthed to
include cumulative schemes)
Proposed Development Flows
during Land Raising (prior to
mitigation)
% increase (prior to mitigation)
Total Vehicles
HGVs Total
Vehicles HGVs
Total Vehicles
HGVs
Avonmouth Way / McLaren Road / King Road / A403
(Location 3 on Figure 10-1 (Volume III)
AM Peak
(0800-0900) 1,996 638 26 26 1% 4%
PM Peak
(1700-1800) 1865 386 26 26 1% 7%
10.5.15. Table 10-3 demonstrates that the predicted maximum increase in percentage
HGVs during the land raise activity is predicted to be 21% in the morning peak
and 23% in the evening peak at the junction A403 / Severn Road / Chittening
Road. The increase in total vehicles at this junction is 6-7%, when taking into
account the large number of light vehicles using these roads.
10.5.16. It should be noted that this level of increase is calculated based on a number of
conservative assumptions outlined above and without assuming any
interventions/mitigation measures, which are discussed later in this chapter.
10.5.17. Despite the conservative assumptions applied to this assessment, the magnitude
of change shown is less than the 30% threshold noted by IEMA for requiring
further consideration. The level of change anticipated is considered to be
negligible.
10.5.18. Furthermore, given the general absence of residential areas along the A403, the
area is not considered sensitive to this level of traffic increase. The residential
settlement of Avonmouth is located south of the roundabout Avonmouth Way /
McLaren Road / King Road / A403. Other nearby residential areas includes
Lawrence Weston, Hallen and Severn Beach. However, the A403 does not run
through any residential settlements.
10.5.19. Sensitivity tests have been undertaken to establish the effect should the HGVs
be routed via the M5 through Junction 19 to the A4 (Location 6 on Figure 10-1,
Volume III of this PEI Report) or via the M48 (Location 4 on Figure 10-1, Volume
III of this PEI Report). The results of these tests are presented in Table 10-4.
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Table 10-4: Traffic Increase during Land Raising Prior to Additional Mitigation – Sensitivity Test
Location Time period
2019 Base Flows (Growthed to
include cumulative schemes)
Proposed Development Flows
during Land Raising (prior to
mitigation)
% increase (prior to mitigation)
Total Vehicles
HGVs Total
Vehicles HGVs
Total Vehicles
HGVs
Traffic towards the A4 from the M5 (north)
Location 6 on Figure 10-1 (Volume III)
AM Peak
(0800-0900) 1,833 338 13 13 1% 4%
PM Peak
(1700-1800) 1,128 363 13 13 1% 4%
Daily 15,726 3,403 130 130 1% 4%
A403 - between B4055 and M48
Location 4 on Figure 10-1 (Volume III)
AM Peak
(0800-0900) 617 96 26 26 4% 27%
PM Peak
(1700-1800) 694 97 26 26 4% 27%
Daily 7,981 1,603 260 260 3% 16%
10.5.20. The HGV increases for this location are 4% for both peaks as well as for daily
flows. For the final sensitivity test, significantly less base flows is seen at this
location compared to the junctions south of the Proposed Development Site and
therefore a higher percentage increase is expected (a 27% increase in HGVs
during peak hours). However, the overall traffic figures are significantly lower for
all scenarios.
Construction Phase
10.5.21. The peak month of construction activity (in terms of traffic generation) is expected
to occur in month 25 of the construction schedule (see Chapter 5: Enabling
Works and Construction), which is currently envisaged to be 2019. Activities likely
to be taking place during this period include the construction of the main plant
buildings, water demineralising treatment plant, gas pressure reducing station,
pipe bridges and cable racking.
10.5.22. The required workforce during the construction period is expected to reach a
peak of approximately 790 construction workers onsite in 2019. This estimate
has been obtained from one of the potential contractors who is likely to be invited
to bid for the construction works and is therefore considered a reasoned
estimation of worker numbers onsite.
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10.5.23. An additional 100 staff are expected to be required to construct the associated
infrastructure, which mainly comprises the proposed cooling water pipeline and
electricity cables, but it is not expected that this will correspond with the peak
month of construction onsite; the cooling water pipeline will be constructed in
2020 and 2021 based on the current programme. Hence, realistically 790
workers are expected to represent the estimated maximum number of workers on
the project in any one month.
10.5.24. Prior to any intervention or management of worker trips, a car/van occupancy
rate of 1.35 has been adopted, resulting in approximately 585 vehicles accessing
the Proposed Development Site daily, if it is conservatively assumed that none of
the workforce travel to Site by other modes. This is the equivalent to 1,171 two
way trips. The car occupancy rate of 1.35 is generally accepted in the
construction industry and indeed a figure that has been used and accepted in the
assessment of other proposals involving the construction of power stations.
10.5.25. A gravity model has been developed to estimate where construction worker
vehicles may travel from and define their route to the Proposed Development
Site. Using employment data from the Office of National Statistics (Ref. 10-6), as
shown in Appendix E, Volume II of this PEI Report, a distribution profile has been
developed based on the number of residents working in the construction sector in
each local authority within defined catchment areas as outlined in this chapter.
10.5.26. The results indicate that a total of 511 vehicles (44%) are expected to access the
Proposed Development Site from the south along the A403 via the A4 and
Hallen, and 660 (56%) are expected to access the Proposed Development Site
from the north via the M48 Junction 1. These figures are expected to reduce
following the introduction of travel plan measures such as shuttle bus services
and car sharing schemes, which are discussed further later in this chapter.
10.5.27. In terms of HGVs, the maximum volume of HGVs on the network is estimated to
peak at 80 two way daily vehicle movements (40 in and 40 out). It is anticipated
that this peak period is likely to also occur within 2019. Outside of this period the
number of two way HGV movements will be an estimated 40 per day (20 in and
20 out).
10.5.28. An assumption that has been applied to the HGV trip distribution during the
construction phase is an even distribution across the network. This is an
approach that has been applied in other Transport Assessments for CCGT power
stations (Ref. 10-7) on the basis that it is not known where material will be
sourced from at this stage. In the case for the Proposed Development Site, it is
therefore assumed that 50% of all HGVs will arrive from north via the M48 and
50% from the south via the A4. Construction material such as steelwork will be
sourced from local suppliers in the Avonmouth / Severnside area where possible;
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the Applicant would propose hosting a series of ‘Meet-the-Buyer’ events to
encourage and identify potential local suppliers.
10.5.29. For the peak hour assessments, the assumptions include:
• The total daily HGV trips are distributed evenly across a 10 hour working
day between 0800 and 1800 Monday to Friday (this is worst-case
designed to coincide with AM and PM peak hour. In reality deliveries will
be allowed 24 hours, 7 days a week and would be schedule to avoid
arrivals in peak hours);
• All HGV trips / deliveries will arrive and depart within the same hour;
• An arrival and departure profile based on other similar sites has been
applied to the construction workers to establish the effects on the road
network during peak hours.
10.5.30. The above has been applied to the assessment to provide a worst-case scenario.
10.5.31. Table 10-5 presents the predicted increase on the local road network during the
main construction works. Daily flows are not provided for the Avonmouth Way /
McLaren Road / King Road / A403 junction and the M4 / M5 to M4 movement on
the Almondsbury Interchange.
Table 10-5: Traffic Increase during Main Construction Works Prior to Additional Mitigation
Road Section / Junction
Time period
2019 base (Growthed traffic flows with
committed developments)
Proposed Development Flows during Construction (prior to mitigation)
% increase (prior to mitigation)
Total Vehicles
HGVs Total
Vehicles HGVs
Total Vehicles
HGVs
A403 just north of junction with existing Seabank access
(Location 1 on Figure 10-1 (Volume III))
AM Peak (0800-0900) 671 125 93 4 14% 3%
PM Peak (1700-1800) 839 112 75 4 9% 4%
Daily 9,905 2,201 551 40 6% 2%
A403 / Severn Road (A403) / Chittening Road
(Location 2 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
439 124 93 4 21% 3%
PM Peak (1700-1800)
372 115 75 4 20% 3%
Daily 11338 2982 551 40 5% 1%
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Road Section / Junction
Time period
2019 base (Growthed traffic flows with
committed developments)
Proposed Development Flows during Construction (prior to mitigation)
% increase (prior to mitigation)
Total Vehicles
HGVs Total
Vehicles HGVs
Total Vehicles
HGVs
A403 (south of junction with M48)
(Location 4 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
627 98 120 4 19% 4%
PM Peak (1700-1800)
709 99 96 4 14% 4%
Daily 8157 1638 700 40 9% 2%
Avonmouth Way / McLaren Road / King Road / A403
(Location 3 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
2090 666 56 4 3% 1%
PM Peak (1700-1800)
1986 407 46 4 2% 1%
Almondsbury Interchange Movement: Southbound, M4/M5, M5 Southbound slip to M4 Westbound
(Location 5 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
238 24 38 1 16% 4%
PM Peak (1700-1800)
301 42 1 1 0% 2%
10.5.32. Table 10-5 shows percentage increases for total vehicle flows during peak hours
of up to 21% predicted along the A403 if no mitigation measures (interventions)
are introduced; the higher increases are partly a reflection of the low baseline
flows however. The total daily increases are significantly lower (between 5% and
9%) at these locations and this suggests that there will be opportunities to
manage movements to reduce these effect during peak hours through the
implementation of a CTMP.
10.5.33. It should be noted that for the traffic effect on the Almondsbury Interchange
(Location 5), only one movement has been assessed reflecting the likely use of
this junction to access the Site, from M5 southbound to M4 westbound.
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10.5.34. As mentioned above, it is likely that the increases presented above are an
overestimate of the actual effect on local traffic flows; in particular, most supliers
of materials will deliberately aim to avoid peak hours. Despite these conservative
assumptions, it is considered that the predicted increase in traffic flow outlined in
Table 10-5 is negligible.
Severance
10.5.35. Severance is the perceived division that can occur within a community when it
becomes separated by a major traffic artery. It may result from the difficulty of
crossing a heavily trafficked existing road for example, or as a result of a physical
barrier created by the road itself.
10.5.36. There are no predictive formulae which give simple relationships between traffic
factors and levels of severance. As detailed above, IEMA guidelines suggest that
only changes in traffic flows of 30% or more are likely to produce changes in
severance on the road network. This threshold is unlikely to be exceeded by
traffic generated by the Proposed Development and associated infrastructure.
Furthermore, given the observed pedestrian and cyclist activity along the study
roads it is considered unlikely that such temporary increases in traffic during
enabling works and the construction phase would result in difficulties for people
to cross the A403.
10.5.37. The predicted increase in total vehicles is expected to be approximately four
vehicles during peak hours along the A403. Furthermore, the implementation of
the CTMP (which will be produced for the final ES) should help site deliveries to
be co-ordinated and managed to minimise disruption to local residents and other
highway users. Therefore the effect of severance during all phases of the
Proposed Development is considered to be negligible.
Driver Delay
10.5.38. Delays to non-development traffic can occur on the network due to the additional
traffic generated during site enabling and construction. The IEMA guidelines note
that these additional delays are only likely to be significant when the traffic on the
network in the study area is already at, or close to, the capacity of the system.
10.5.39. From discussions with SGC, BCC and the HA, it is apparent that there are a
number of junctions where there is limited spare capacity. The junctions identified
are the Almondsbury interchange (junction of M5 and M4) and the A4/A403
signalised roundabout, where junction performance is sensitive to increases in
the number of HGVs.
10.5.40. Driver delay during the peak construction month is not likely to be experienced at
the key junctions on the highway network associated with an increase between
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1% and 4% of HGVs. Therefore the effect of driver delay during the peak month
of traffic generation is considered to be negligible. The effect during other
months and activities is expected to be less and therefore also negligible.
Some driver delay may also occur as a result of the construction of the proposed
cooling water pipeline, although this will be temporary, as it is expected to take a
only few days to trench the pipeline across the affected roads and backfill it. The
affected roads are illustrated in Figure 10-2 (Volume III of this PEI Report).
10.5.41. To minimise delays as far as possible, works will be scheduled during quieter
periods such as weekends where possible and outside of peak hours. To mitigate
significant diversions due to a complete closure of the roads, the pipeline
construction will be staged so that, where ever possible, one lane can be
maintained open, and where necessary, such as at the A403 temporary traffic
lights, the lanes temporarily reinstated to allow access on both lanes during peak
hours.
10.5.42. Taking into account the mitigation measures suggested above and their
temporary nature of this interruption, the effect of the pipeline construction on
driver delay is expected to be negligible.
Abnormal Loads
10.5.43. In addition to the typical HGV deliveries, the delivery of abnormal loads may
result in temporary localised delays which can be managed by implementing the
CTMP. An “abnormal indivisible load” is a load that due to its length, width or
weight cannot be carried without undue expense or risk of damage. These
deliveries therefore require notifications to relevant authorities before being
authorised. The estimated plant type and equipment during Construction
Activities are outlined in in Table 5-2, Chapter 5: Enabling Works and
Construction of this PEI Report.
10.5.44. The CTMP would address temporary road signage requirements, construction
traffic routing and timing. There are anticipated to be only up to 20-30 abnormal
load deliveries during the 37 month construction period (following enabling
works), corresponding with less than 1 a month on average. Delays from
abnormal loads are therefore considered to be negligible.
Pedestrian and Cyclist Delay
10.5.45. Changes in the volume, composition or speed of traffic may affect the ability of
people to cross roads and use them for cycling. There are also potential
pedestrian and cyclist delay should diversion routes be required during the
construction of the proposed cooling water pipeline. In general terms, increases
in traffic levels are likely to lead to greater increases in delay. However, given the
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range of local factors and conditions which can influence pedestrian and cyclist
delay, IEMA does not recommend that thresholds be used as a means to
establish the significance of pedestrian and cyclist delay.
10.5.46. Onsite observations by URS indicated that there is minimal pedestrian and cyclist
activity along the A403. As detailed above, the expected increase even in the
morning peak on a weekday is unlikely to result in difficulties for people to cross
the A403.
10.5.47. Part of the proposed cooling water pipeline corridor runs parallel to an existing
cycle path between Moorend Farm Avenue and the access to the A403, contains
part of a cycle path in the vicinity of the railway, and crosses a cyclepath on
Severn Road. This will require temporary closures to these cycle paths during the
period of works, although a diversionary route will be established and agreed with
BCC in advance of these works commencing.
10.5.48. Taking these factors into consideration, the effect of development generated
traffic on pedestrian and cyclist delay is considered to be negligible.
Pedestrian and Cyclist Amenity
10.5.49. Pedestrian and cyclist amenity is broadly defined as the relative pleasantness of
a journey and is considered to be affected by traffic flow, traffic composition, and
footway width/separation from traffic. The IEMA guidelines note that changes in
pedestrian and cyclist amenity may be considered to be significant where the
traffic flow (or its HGV component) is halved or doubled as a result of
development activity.
10.5.50. As detailed above, taking into account minimal pedestrian and cyclist activity, the
increase in traffic along the A403 is unlikely to affect the pleasantness of
pedestrian and cyclist journeys along the A403. Therefore, the effect of
development related traffic on pedestrian and cyclist amenity is considered to be
negligible.
10.5.51. The construction of the proposed cooling water pipeline will affect some sections
of the PROW and cycle routes, as well as needing to cross beneath the Severn
Beach railway line. Where possible access will be maintained for pedestrians and
cyclists. If at some locations this is not possible, then prior closure notice will be
given and alternative routes identified and signposted. Prior closure notices
normally required 12 weeks of advertising prior to event / closure / diversion.
Given the temporary nature of these closures and the relative low number of
users, these closures are not anticipated to cause a significant impact to
pedestrian and cyclist amenity.
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10.5.52. As part of the operational Proposed Development, the Applicant is committed to
improving the local PROW network and is proposing to create a new PROW from
Ableton Lane within the Proposed Development Site, around the southern
boundary of the CCR Site and connecting to the existing roundabout on the
Spine Access Road to the east of the Site. This will increase the permeability of
the area and also provide improved foot and cycle access to and from the
Proposed Development Site to the A403. This additional permeability of the area
is considered a minor beneficial effect on pedestrian and cyclist amenity.
Public Transport
10.5.53. Potential effects on the bus and rail network of additional patronage could
include:
• Crowding on buses and trains;
• Congestion at bus stops and stations; and
• Congestion on footpaths on routes to bus stops and stations.
10.5.54. The construction workers’ Travel Plan will aim to encourage workers to use public
transport as far as is practical. It is anticipated that sufficient capacity is available
on the existing services as the majority of workers would use services outside of
peak hours where possible due shift staring / finishing times.
10.5.55. Given the variety of public transport options available in the area, combined with
the likelihood that most workers will arrive to site by car, the effect on public
transport services of the construction phase of the Proposed Development Site
and associated infrastructure is expected to be negligible.
Fear and Intimidation
10.5.56. The scale of fear and intimidation experienced by pedestrians and cyclists is
dependent on the volume of traffic, its HGV composition, its proximity to people
or the lack of protection caused by factors such as narrow pavement widths.
However, there are no commonly agreed thresholds by which to determine the
significance of the effect.
10.5.57. The highest estimated percentage increase in HGV traffic resulting from
construction is 21% during peak hour. However, the level of pedestrian and
cyclist activity along the A403 up to the proposed access points is considered
minimal. This also only reflects a 6-7% increase in total flows, and is based on a
series of conservative assumptions that are likely to have overestimated the trip
generation.
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-27
10.5.58. A CTMP will be produced for the final ES that considers construction traffic routes
and timings of traffic movements (e.g. to reduce the risk of vehicles convoying),
to be agreed with the HA, SGC and BCC. Following implementation of the CTMP
it is considered that the scale of fear and intimidation experienced by pedestrians
and cyclist would be negligible.
Accidents and Safety
10.5.59. Due to the numerous local causation factors involved in Personal Injury
Accidents, the IEMA guidelines do not recommend the use of thresholds to
determine significance.
10.5.60. Given that construction is temporary, the changes predicted are temporary, and
the estimated hourly traffic generation is relatively low to the total flows on the
roads. It is therefore considered unlikely that there would be an impact upon road
safety and accident levels due to Proposed Development traffic. As described
earlier in this chapter, the A403 is not considered to be an accident problem area.
10.5.61. The potential effects of abnormal loads on highway safety are considered to be
not significant, given that they will be relatively few in number and will be
managed through appropriate traffic management procedures and following
notification of the appropriate authorities. Furthermore, all abnormal loads will be
escorted and the movement of these vehicles will be programmed to avoid busy
periods.
10.5.62. A potential effect on highway safety relates to the transfer of dirt and debris from
the Proposed Development Site onto the carriageway. Mitigation measures to
minimise this effect are outlined further detail in Chapter 11: Air Quality.
10.5.63. In conclusion, the risk of accidents is considered to be negligible, prior to the
implementation of any mitigation measures.
Assessment of Operational Effects
10.5.64. As agreed with SGC, BCC and the HA, the operational phase has been scoped
out of the traffic and transport assessment. The operational Proposed
Development is estimated to require up to 40 workers on site over three 8 hour
shifts per day (i.e. approximately 13 staff at any one time onsite). This may be
reduced further if the site is managed collaboratively along with Seabank 1 & 2.
10.5.65. Traffic associated with maintenance and deliveries (distillate fuel deliveries for
example) will be minimal, with up to a maximum 24 daily movements (12
deliveries) expected following a black start event (which is likely to be an
infrequent event, perhaps only once per year). It is also expected that these
deliveries would be distributed over a period of several days.
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-28
10.5.66. The effect of traffic flows during operation is therefore predicted to be negligible.
10.5.67. As identified above, the delivery of a new PROW is anticipated to lead to a minor
beneficial effect on pedestrian and cyclist amenity.
Assessment of Decommissioning Effects
10.5.68. It is envisaged that the plant will have a design life of 30 years, with an operating
life possibly beyond this. It is not possible to accurately predict the
decommissioning traffic flows and junction capacities at this point in the future,
however it is anticipated that there would be far fewer vehicle and workers
numbers during decommissioning than in construction. It is also expected that
decommissioning would be relatively short in comparison to the construction
period and therefore only a short-term, temporary effect.
10.5.69. The significance of the effect of decommissioning traffic is therefore anticipated
to be negligible.
Mitigation Measures
10.5.70. The mitigation measures considered for the Proposed Development and
associated infrastructure is principally targeted at reducing cumulative effects.
10.5.71. A CTMP will be produced to accompany the DCO Application to manage HGV
and worker movements associated with the Proposed Development. The plan will
aim to ensure that the number of HGV movements is reduced as far as possible
during periods when traffic on the surrounding road network is busy. This
includes peak hour and shoulder peaks, school holiday times and bank holiday
weekends. Any access route restrictions, where these may be deemed
necessary, will be included in the CTMP.
10.5.72. Storage areas will be provided onsite so night-time and weekends deliveries can
be maximised as far as possible. The noise effects associated with this are
assessed in Chapter 12: Noise and Vibration. This will also apply to the land
raising work during the enabling works phase.
10.5.73. The key mitigation measures likely to be included in the CTMP include:
• Promoting public transport by introducing shuttle bus services between
the DCO Site and Avonmouth Railway station and Bristol Parkway
Railway station (not for public use);
• Introducing a car sharing scheme to increase the car occupancy rate; and
• Promoting cycling, although due to the location of the DCO Site in relation
to the worker catchment area cycling as a mode a transport is likely to be
limited to a very small proportion of staff.
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-29
10.5.74. These mitigation measures are required to mitigate cumulative effects rather than
the effect of the Proposed Development in isolation (which is negligible); however
such measures in the Travel Plan would be expected to reduce the number of
vehicles on the highway network during peak times associated with the Proposed
Development and are therefore discussed here. The figures have been derived
from a model presented in further detail in the TA. The results are presented in
Table 10-6.
Table 10-6: Predicted Increase during Construction Phase following Mitigation Measures
Road Section / Junction
Time period
2019 Base (Growthed traffic
flows with committed
developments)
Proposed Development Flows during construction
(after mitigation)
% increase
(after mitigation)
Total Vehicles
HGVs Total
Vehicles HGVs
Total Vehicles
HGVs
A403 just north of junction with existing Seabank access
(Location 1 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
671 125 53 4 8% 3%
PM Peak (1700-1800)
839 112 43 4 5% 4%
Daily 9,905 2,201 320 40 3% 2%
A403 / Severn Road (A403) / Chittening Road
(Location 2 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
439 124 53 4 12% 3%
PM Peak (1700-1800)
372 115 43 4 12% 3%
Daily 11,338 2,982 320 40 3% 1%
A403 (south of junction with M48)
(Location 4 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
627 98 74 4 12% 4%
PM Peak (1700-1800)
709 99 60 4 8% 4%
Daily 8,157 1,638 439 40 5% 2%
Avonmouth Way / McLaren Road / King Road / A403
(Location 3 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
2,090 666 33 4 2% 1%
PM Peak (1700-1800)
1,986 407 27 4 1% 1%
Almondsbury Interchange Movement: SB, M4/M5, M5 Southbound slip to M4 Westbound
(Location 5 on Figure 10-1 (Volume III))
AM Peak (0800-0900)
238 24 18 1 8% 4%
PM Peak (1700-1800)
301 42 1 1 0% 2%
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May 2014 Page 10-30
10.5.75. Table 10-6 shows the predicted effect on the highway network following the
potential introduction of the mitigation measures. An increase of 12% is expected
in the AM and PM peak on the junction A403 / Severn Road (403) / Chittening
Road (south of proposed access points) and in the AM peak on the A403 towards
the junctions with M48. This is a reduction of between 7% and 9% compared to
the scenario where no mitigation measures have been introduced. Similarly, a
significant reduction is expected on the junction A403 / Severn Road (A403) /
Chittening Road, following the introduction of Travel Plan measures.
10.6. Residual Effects
10.6.1. Despite the combination of conservative assumptions assumed in this
assessment, there are not predicted to be any residual traffic and transport
effects associated with the Proposed Development and associated infrastructure.
10.6.2. Table 10-7 summaries the residual effects during the peak month of the main
construction phase as this represents the worst-case scenario; despite this the
predicted effect is negligible, with the exception of pedestrian and cyclist
amenity which would be minor beneficial because of the proposed provision of
a new PROW. The predicted effect during the remainder of the enabling works,
construction, operational and decommission phases is expected to be less than
this and therefore also negligible.
Table 10-7: Summary of Residual Effects
Potential Effect Mitigation Measures Significance of the Residual Effect
Severance n/a Negligible
Driver Delay Travel Plan measures such as a Shuttle bus services car sharing schemes
Negligible
Pedestrian and Cyclist Delay
n/a Negligible
Pedestrian and Cyclist Amenity
Provision of new PROW Minor beneficial
Fear and intimidation n/a Negligible
Accident and Safety Avoid peak and busy periods where possible. Abnormal loads to be escorted.
Negligible
10.7. Cumulative Effects
10.7.1. A significant number of other schemes are either being developed or planned in
the area. The future baseline is calculated for 2019 as this year is expected to
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-31
experience the month with the highest demand for personnel accessing the
Proposed Development Site during the construction phase.
10.7.2. Transport studies and assessments published for committed nearby
developments have been reviewed and considered for the cumulative effect.
Based on this review it is considered reasonable to assume that all the
cumulative schemes outlined in Chapter 7: Assessment Methodology would be in
operation by 2019, with the exception of Avon Power Station for which an
application has not yet been submitted and Hinkley C Connection Project.
10.7.3. As mentioned above, these cumulative schemes have been included within the
future, 2019 baseline, as well as a growth factor that may have double counted
the effect of some schemes. The predicted effect of Avon Power Station has
been excluded from the assessment because of the uncertainty associated with
this development and whether it will proceed and when. It is expected the
operational traffic associated with Avon Power Station would be of similar scale
to the Proposed Development, with approximately 10 staff expected during each
shift, which should therefore not give rise to any significant cumulative effects
when considered along with the Proposed Development and other schemes in
the area. Should the construction phase overlap with the Proposed Development,
it is envisaged that the Contractors for each development would liaise with one
another to minimise the number of trips during peak hours and disruption to the
local communities. Any application for the Avon Power Station scheme is likely to
be subsequent to the DCO Application for the Proposed Development however,
and therefore a rigorous assessment of cumulative effects during the
construction period would be expected to be undertaken by the Applicant for that
scheme.
10.7.4. The HA and transport officers at SGC and BCC have also raised concerns
regarding the potential transport effect of the construction of Hinkley Point C
nuclear power station; this is a proposed development for a new 3,200MW two
reactor nuclear power station near Bridgwater, Somerset, which is likely to be
under construction in 2019 (pending discharge of conditions). Through
communications with the Hinkley Development Management at West Somerset
Council as well as the Transport Coordinator from the Applicant, it is understood
that Hinkley Point C is expected to complete commissioning of the first unit in
2023, which would mean that the peak construction might occur in 2018.
However, these dates cannot be confirmed at this stage as the financial
commitments have yet to be made. Furthermore, no trip distribution analysis is
available beyond Junction 23 and 24 on the M5 within the study area to allow the
consideration of cumulative effects with the catchment of the Proposed
Development. As the predicted effect of the Proposed Development has been
shown to be negligible, it therefore should not contribute to any cumulative
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-32
effects with Hinkley Point C. It has therefore not been deemed necessary to
assess this scheme further.
10.7.5. In addition, the Hinkley C Connection Project, which is the construction of OHL
from Hinkley C to Seabank Substation and upgrade works at the substation, is
predicted to have a negligible effect on the A403 and other study roads
considered in this assessment. There is not considered to be any potential for
significant cumulative effects therefore arising from the overlap in construction
period between this scheme and the Proposed Development; this will be
reviewed following the submission of the DCO Application for the Hinkley C
Connection Project (expected in Spring 2014).
10.7.6. Table 10-8 presents a summary of the cumulative effects along the A403,
comparing the following scenarios:
• 2013 baseline flows;
• 2019 flows, including background growth and cumulative traffic; and
• 2019 with background growth and cumulative traffic along with peak
construction traffic associated with the Proposed Development.
Table 10-8: Predicted Cumulative Effects (Total Traffic including HGVs)
Road Section / Junction
Time period 2013
Baseline
2019 Baseline
(incl. cumulative schemes)
Increase from 2013
(due to cumulative schemes)
2019 (incl. cumulative schemes) + Proposed
Development (with
mitigation)
Increase from 2013
(due to Proposed
Development and
cumulative schemes)
A403 just north of junction with existing Seabank 1 & 2 access
(Location 1 on Figure 10-1)
AM Peak (0800-0900)
623 671 7.7% 724 16.2%
PM Peak (1700-1800)
777 839 8.0% 882 13.5%
Daily
9,270 9,905 6.9% 10,225 10.3%
A403 / Severn Road (A403) / Chittening Road
(Location 2 on Figure 10-1)
AM Peak (0800-
0900)
359 439 22.2% 492 37.0%
PM Peak (1700-1800)
304 372 22.4% 415 36.5%
Daily
10,611 11,338 6.9% 11,658 9.9%
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-33
10.7.7. The cumulative schemes are predicted to increase traffic flows by approximately
7% to 8% along the A403 just north of the existing junction with Seabank 1 & 2.
The daily increase along A403 / Severn Road (A403) / Chittening Road is
approximately 7% due to these other schemes, although increases to
approximately 22% during the AM and PM peak hours.
10.7.8. When also considering the construction traffic associated with the Proposed
Development, and comparing this against 2013 baseline traffic flows, the daily
increase is in the order of 8-9% along these road links. The effect during peak
hours is larger and is shown to be 16.2% and 13.5% for the AM and PM peak
respectively along the A403 just north of the existing junction with Seabank 1 & 2.
The change along A403 / Severn Road (A403) / Chittening Road is 37.0% during
both peak hours.
10.7.9. The magnitude of change exceeds the 30% threshold suggested by IEMA for
peak hours, however as discussed above the assessment has incorporated a
number of conservative assumptions (which may have led to double counting of
the cumulative schemes) and most importantly, it has been based on the peak
month of construction. The rest of the construction period is expected to lead to
less traffic and deliveries are likely to be timed deliberately to avoid these peak
hours. Any minor adverse effect therefore that may be predicted is expected to
be short-term, with the majority of the construction period negligible.
10.7.10. The cumulative effects during operation are expected to be much less and
therefore negligible.
10.8. Impacts and Effects yet to be Determined
10.8.1. There are no impacts and effects yet to be determined, however, the scheme
design or anticipated peak year of construction may be subject to change prior to
submission of the final DCO application. Any changes that lead to differing or
new impacts and effects will be highlighted within the final ES, along with the
reasons for the change.
10.8.2. It is also likely that the baseline conditions will change between the preparation of
this PEI Report and the final ES. The Proposed Development Site is currently
subject to excavation, top soil stripping, and levelling in certain areas in order for
third parties to deliver the Spine Access Road and new channel for the Red
Rhine, which are discussed in Chapter 2: The DCO and EIA Process and
Chapter 7: Assessment Methodology. A haul road is also being constructed
through the middle of the Proposed Development Site to enable access by third
party from the roundabout to the east of the Site to the Severnside Energy
Recovery Centre to the west. These works onsite are being undertaken by other
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-34
developers, under extant planning permissions and are separate to the Proposed
Development.
10.8.3. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changed
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
10.8.4. The list of cumulative schemes that require consideration in the cumulative effect
assessment is also dynamic and subject to change. The final ES will take
account of changes to the status and nature of these schemes. The aspirational
M49 junction development may also need to be considered if the Planning
Inspectorate is formally notified that it should expect a DCO Application in the
near future.
10.8.5. A CTMP and a construction Travel Plan have not been prepared as part of this
PEI Report but will be appended to the final ES. Where applicable, the findings of
these reports will be summarised in the final ES chapter.
10.8.6. It is anticipated that a detailed assessment of traffic increases on the A4
signalised roundabouts will be included in the final ES and TA, along with
capacity analysis for the following roads and junctions:
• Merge diverge assessment at M48 junction 1;
• A403 Smoke Lane/Poplar Way West priority roundabout;
• A403 St Andrew’s Road/Kings Weston Lane (signalised junction);
• A403 St Andrew’s Road/St George’s Industrial Estate;
• A403/Redwick Road in Pilning; and
• A403 Chittening Road / Severn Road.
10.9. References
Ref 10-1 Institute of Environmental Assessment (IEA) (1993) Guidance Notes
No. 1: Guidelines for the Environmental Assessment of Road Traffic
Ref 10-2 Viridor. Transport Assessment for Viridor Resource Recovery Centre,
Ref 10-3 Department for Transport (DfT) AADF (Annual Average Data Flow)
Database
Ref 10-4 Highways Agency, TRADS database
Ref 10-5 SITA (2012) Environmental Statement Volume 4; Non0Technical
Summary (April 2012) Bottom Ash Recycling Facility & Railhead
Seabank 3 PEI Report – Chapter 10 Traffic and Transport
May 2014 Page 10-35
Ref 10-6 Office for National Statistics. Nomis Data ‘Annual business inquiry
employee analysis SIC’
Ref 10-7 Transport Assessment for Killingholme Power Station, Drakelow CCGT
Power Station and High Marnham CCGT Power Station
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-1
11. Air Quality
11.1. Introduction
11.1.1. The purpose of this chapter is to assess the potential effects of emissions to air
resulting from the construction and operation of the Proposed Development.
11.1.2. It describes the assessment methodology, the baseline conditions at the
Proposed Development Site and its surroundings, any mitigation measures
required to prevent, reduce or offset any significant adverse effects and the likely
residual effects after these measures have been employed.
11.1.3. The assessment considers:
• The present-day and future baseline conditions during construction and
operation;
• The effects of enabling works and construction of the Proposed
Development on air quality for human health and ecosystems, with
respect to associated construction traffic, construction plant emissions
and construction dust;
• The effects of operational process emissions associated with the
Proposed Development on air quality for human health and ecosystems;
and,
• The cumulative effects of emissions associated with the Proposed
Development and other committed developments in the vicinity.
Consultation
11.1.4. A scoping request was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on the proposed structure,
methodology and content of this chapter and subsequent ES.
11.1.5. Table 11-1 provides a summary of stakeholder comments relevant to air quality
and how they have been incorporated into this PEI Report chapter.
Table 11-1: Summary of Consultation Responses Relevant to Air Quality
Consultee Key Issues / comments
Location of
information in
Chapter
Planning Inspectorate
Noting the proximity of the site to the designated Cribbs Causeway Air Quality Management Area (AQMA), it is suggested that changes should be assessed in relation to compliance with European air quality limits and AQMAs.
Section 11.3 and 11.5
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-2
Table 11-1: Summary of Consultation Responses Relevant to Air Quality
Consultee Key Issues / comments
Location of
information in
Chapter
Consider whether use of the 2010 Local Monitoring Data, supplemented by Local Authority diffusion tube sampling and Defra background air quality maps, is sufficiently thorough, accurate, up to date and takes account of other development proposed in the vicinity.
Section 11.2 and 11.3
The ES should clearly explain the relationship between stack heights and dispersion of emissions to air.
Section 11.4 and 11.5
The assessment should take account of both the air emissions from the proposed development and emissions related to increased vehicular movements.
Section 11.5
The impacts on the Severn Estuary should be carefully assessed.
Section 11.5
Air quality and dust emissions should be considered not only on site but also off site, including along access roads, local footpaths and other PROW.
Section 11.5
SGC
It would be prudent to consider monitoring, possibly with automatic analysers, at the point of predicted maximum impact to quantify the impact of the proposed development and other proposed development in the area.
Section 11.2 and 11.3
BCC
It would be prudent at this stage not to rule out ambient monitoring of potential air quality impacts considering the potential cumulative impacts from this and other committed developments in the area.
Section 11.2 and 11.3
EA No written response relevant to air quality. -
Countryside Council for Wales (CCW)
Depending on the quantities and nature of material that may be discharged to air, the restriction of assessment of possible impacts to 10km is not necessarily appropriate for European sites. We recommend that 10km is used as an initial screening distance to determine whether there are any impacts on designated features. If the assessment identifies potential impacts then increasing the search beyond 10km may be pertinent.
Section 11.5
South Wales Fire and Rescue Service
The ES should include information as to the environmental impact of the project on South Wales.
Section 11.5
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May 2014 Page 11-3
11.1.6. Following receipt of the scoping opinion, technical notes on preliminary stack
height determination work and the proposed approach to gathering baseline data
were issued to the EA, SGC and BCC, which led to additional comments being
received on the proposed methodology. Other than SGC recommending that a
suitable bias adjustment should be applied to the primary data collection in this
PEI Report, the suggested approach (outlined in this chapter) was accepted by
the EA, SGC and BCC.
Legislation and Planning Policy Context
11.1.7. A summary of planning policy relevant to this assessment is provided in
Appendix D: Volume II of this PEI Report.
11.1.8. The principal air quality legislation within the United Kingdom is the Air Quality
Standards Regulations 2010 (Ref. 11-1) which transposes the requirements of
the European Ambient Air Quality Directive 2008 (Ref. 11-2) and the 2004 Fourth
Air Quality Daughter Directive (Ref. 11-3).
11.1.9. The Regulations set air quality limits for a number of major air pollutants that
have the potential to impact public health, such as nitrogen dioxide (NO2),
sulphur dioxide (SO2) and particulate matter. Target values for other pollutants
including critical levels for the protection of vegetation and ecosystems are also
included.
11.1.10. The UK Government has produced a National Air Quality Strategy (NAQS) (Ref.
11-4), which contains air quality objectives and timescales to meet the objectives.
These objectives apply to outdoor locations where people are regularly present
and do not apply to occupational, indoor or in-vehicle exposure. It requires Local
Authorities to undertake an assessment of local air quality to establish whether
the objectives are being achieved, and to designate Air Quality Management
Areas (AQMAs) if improvements are necessary to meet the objectives. Where an
AQMA has been designated, the Local Authority must draw up an air quality
action plan (AQAP) describing the measures that will be put in place to assist in
achieving the objectives.
11.1.11. The current objectives and assessment criteria applicable to the protection of
human health and/or local air quality management are presented in Table 11-2.
Concentrations are expressed in micrograms per cubic metre (µg/m3), unless
otherwise stated. This does not apply to workers or commercial/ industrial
premises, which are subject to the Health and Safety limits (which are typically a
factor of 1,000 less rigorous than the Air Quality Strategy objectives and
therefore are not likely to be exceeded by the Proposed Development).
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Table 11-2: Air Quality Strategy Objectives – Protection of Human Health
Pollutant Objective
(µg/m3)
1
Averaging
Period Percentile
Nitrogen Dioxide (NO2) 200 1-hour
99.8th
(18 exceedances/year)
40 Annual Mean
Sulphur Dioxide (SO2)
266 15-minute 99.9
th
(35 exceedances/year)
350 1-hour 99.7
th
(24 exceedances/year)
125 24-hour 99.2
nd
(3 exceedances/year)
Particulate Matter (PM10) 2
50 24-hour 98
th
(7 exceedances/year)
40 Annual Mean
Particulate Matter (PM2.5) 3 25 Annual Mean
Carbon monoxide (CO) 10,000 8-hour 100
th
(0 exceedances/year)
Lead (Pb) 0.25 Annual Mean
1,3 butadiene 2.25 Annual Mean
Benzene 5.0 Annual Mean
Polycyclic Aromatic Hydrocarbons (PAH)
0.25 ng/m3 4
Annual Mean
1 µg/m
3 = micrograms per cubic metre – a microgram is a millionth of a gram.
2 PM10 = Particulate matter with an aerodynamic diameter of less than 10 microns (µm).
3 PM2.5 = Particulate matter with an aerodynamic diameter of less than 2.5µm.
4 ng/m
3 = nanograms per cubic metre – a nanogram is a billionth of a gram.
11.1.12. A number of critical levels have also been developed for the protection of
vegetation and ecosystems (CLPVEs), which are presented in Table 11-3.
Table 11-3: Critical Levels for the Protection of Vegetation and Ecosystems
Pollutant Objective
(µg/m3)
Averaging
period Notes
Oxides of nitrogen (NOx as NO2)
75
*30
Daily mean
Annual mean
-
Sulphur dioxide (SO2) 10
1
*20 2
Annual mean 1 For lichens and bryophytes
2 For all higher plants Ammonia
1 1
3 2
Annual mean
Hydrogen fluoride
(HF)
5
0.5
Daily mean
Weekly mean -
Table Notes: * denotes objective set in Air Quality Standards Regulations 2010
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11.1.13. The EU Industrial Emissions Directive (IED) (Ref. 11-5) replaces seven separate
EU directives, including the Large Combustion Plant Directive (LCPD) and
Integrated Pollution Prevention and Control Directive (IPPC).
11.1.14. The IED provides operational limits and controls to which Large Combustion
Plant such as the Proposed Development must comply, including Emission Limit
Values (ELVs) for pollutant releases to air.
11.1.15. In addition, a Best Available Techniques (BAT) reference document (BREF) is
published for each industrial sector covered by the IED, which details Achievable
Emission Levels associated with the use of BAT (BAT-AELs). The most recently
finalised version of the Large Combustion Plant BREF was published in 2006
(Ref. 11-6) although it is currently undergoing review. It is therefore considered
that the use of the ELVs specified in the IED for Large Combustion plant will
enable a robust assessment to be carried out of the potential impacts of the
Proposed Development.
11.1.16. The Environmental Permitting (England and Wales) (Amended) Regulations
2010 (EPR) (Ref. 11-7) transpose the requirements of the IED into UK legislation.
An Environmental Permit will be required for the operation of the Proposed
Development; this would be determined, granted and regulated by the
Environment Agency.
11.2. Assessment Methodology and Significance Criteria
Overview
11.2.1. This section describes the methods used to assess the significance of effects of
emissions from construction phase activities and operation of the Proposed
Development. Baseline conditions, including air quality sensitive receptors that
may be affected by the construction or operation of the Proposed Development,
are discussed in Section 11.3.
11.2.2. The study area for construction road traffic emission impacts extends up to 1.5km
from the Proposed Development Site with receptors identified along routes to and
from the Site. The assessment of road traffic impacts has been based on
conservative traffic estimates for the construction of the Proposed Development.
Further details of the traffic data utilised in the assessment are presented in
Appendix F, Volume II of this PEI, and Chapter 10: Transport and Access.
11.2.3. Road traffic associated with the operation of the Proposed Development will be
minimal and has been scoped out of the Air Quality Assessment.
11.2.4. The study area for combustion emissions extends up to 10km from the Site, in
order to assess the potential impacts on sensitive human health and ecological
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receptors, in line with EA EPR H1 guidelines (Ref 11-8). However, in practice the
predicted impacts become negligible beyond a distance of around 3km from the
Proposed Development. The assessment of process emissions has been based
on conservative emission parameters and including statutory obligations to meet
the Emission Limit Values (ELVs) specified in the IED for Large Combustion
Plant, in order to predict the worst-case impact. In addition, the assessment has
taken into consideration the sensitivity of predicted results to model input
variables, and to ultimately identify the realistic worst-case results for inclusion in
the assessment. These variables include 5-years’ data from a representative
meteorological station, varying surface roughness and representation of buildings
and structures that could affect dispersion from the source and are discussed in
Appendix F, Volume II of this PEI Report.
Construction Phase
Assessment of Emissions Generated from Construction Site Plant
11.2.5. As described in Chapter 5: Enabling Works and Construction, it is intended that
the DCO will allow construction to start within 7 years of receipt of the Order. It is
anticipated that the enabling works phase for the Proposed Development will last
approximately 17 months, followed by the construction phase being anticipated to
last a total of 37 months. The current estimated completion date is in 2021,
however in order to provide a robust assessment (and taking into account
baseline conditions and emission factors are predicted to improve with time, and
therefore improve baseline conditions) this assessment is based on the earliest
possible operational date, which is 2019.
11.2.6. Emissions to air during construction activities will be associated with on-site
construction vehicles and plant. The screening criterion in the Design Manual for
Roads and Bridge (DMRB) (Ref 11-9), which states that only properties and
habitat sites within 200m of roads should be considered in traffic assessments,
has been applied to determine the potential for impacts from construction plant
on sensitive receptors for the Proposed Development.
Assessment of Dust Emissions Generated During Construction Works
11.2.7. Fugitive emissions of airborne particulate matter can be produced through a wide
range of site preparation and construction activities, including:
• Earthworks, including the handling, working and storage of materials;
• Construction activities; and
• The transfer of dust-making materials from the site onto the local road
networks (“track-out”).
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11.2.8. The Proposed Development is not anticipated to include the requirement for
demolition activities, therefore this scenario is not considered further.
11.2.9. ‘Dust’ is defined in BS 6069:1994 (BSI, 1994) as particulate matter in the size
range 1µm - 75µm in diameter, and is primarily composed of mineral materials
and soil particles. This definition is also referred to in NPPF technical guidance
(Ref 11-10) in the context of dust impacts from mineral extraction operations and
has been adopted in this assessment.
11.2.10. Respirable particulate matter (PM10) is composed of material with an
aerodynamic diameter of less than 10µm in diameter, and includes the size
fractions of greatest concern to impacts on human health. The majority of
construction dust is larger than 10µm in diameter and, therefore, increased levels
of dust in the air do not necessarily equate to an increase in levels of PM10. In
general, construction dusts rarely represent an adverse risk to human health and
are more typically associated with the consequences of material depositing onto
property and potential nuisance. Particulate matter may therefore have an effect
whilst airborne, or as a result of its deposition onto a surface. Consequently the
nature of the impact requiring assessment varies between different types of
receptor.
11.2.11. The occurrence and significance of dust generated by earth moving operations is
difficult to estimate, and depends heavily upon the meteorological and ground
conditions at the time and location of the work, and the nature of the actual
activity being carried out. The Institute of Air Quality Management (IAQM)
Guidance on Construction Impacts (Ref. 11-11) provides a screening
methodology to assess the risks from construction activities of nuisance dust
soiling, harm to ecological receptors and health effects from increased PM10
emissions on sensitive receptors. The assessment undertaken for this chapter is
consistent with the overarching approach to the assessment of the impacts of
construction and the determination of their significance set out in IAQM guidance.
It considers the significance of potential impacts with standard mitigation in place
and recommends mitigation measures appropriate to the identified risks to
receptors.
11.2.12. At present, there are no statutory UK or EU standards relating to the assessment
or control of nuisance dust. The emphasis of the regulation and control of
construction dust should therefore be the adoption of Best Practicable Means of
working on site. Designing around the use of good practice is a process that is
informed by impact assessments with the intention of avoiding the potential for
significant adverse environmental effects at the design stage and through
embedded mitigation where possible.
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11.2.13. Examples of accepted good site practice include guidelines published by the
Building Research Establishment (BRE) (Ref. 11-12), the Greater London
Authority and Considerate Contractor schemes.
11.2.14. A qualitative dust assessment has been undertaken to assess the potential
significance of any effects on sensitive receptors. The steps in the assessment
process are to consider potential sources of emissions on the basis of the three
main activity groupings for this development of earthworks, construction and
track-out. For each activity group the same steps are applied with respect to the
potential impacts at identified receptors, before coming to an overall conclusion
about the likely significance of the effects predicted.
11.2.15. The steps in this assessment are to:
• Identify the nature, duration and the location of activities being carried out;
• Establish the risk of significant effects occurring as a result of these
activities;
• Review the proposed or embedded mitigation measures for good site
practice;
• Identify additional mitigation measures, if necessary, to reduce the risk of
a significant adverse effect occurring at receptors; and,
• Summarise the overall effect of the works with respect to fugitive
emissions of particulate matter and then report the significance of the
effects.
Assessment of Construction Road Traffic
11.2.16. The incomplete combustion of fuel in vehicle engines results in the presence of
hydrocarbons (HC) such as benzene and 1,3-butadiene, as well as the typical
combustion products of CO, PM10, PM2.5 in exhaust emissions. In addition, at the
high temperatures and pressures found within vehicle engines, some of the
nitrogen in the air and the fuel is oxidised to form NOx, mainly in the form of nitric
oxide (NO), which is then converted to NO2 in the atmosphere. NO2 is associated
with adverse effects on human health. Better emission control technology and
fuel specifications are expected to reduce emissions per vehicle in the long term.
Similarly but to a lesser extent, any sulphur in the fuel can be converted to
sulphur dioxide (SO2) that is then released to atmosphere.
11.2.17. Although SO2, CO, benzene and 1,3-butadiene are present in motor vehicle
exhaust emissions, detailed consideration of the associated impacts on local air
quality is not considered relevant in the context of this Proposed Development.
This is because the concentrations of release are not likely to give rise to
significant effects. In particular, no areas within the administrative boundaries of
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May 2014 Page 11-9
SGC or BCC are considered to be at risk of exceeding the relevant objectives for
these species, and the risks to achievement of the relevant air quality objectives
from the Proposed Development are considered negligible. Emissions of SO2,
CO, benzene and 1, 3-butadiene from road traffic are therefore not considered
further within this assessment.
11.2.18. Exhaust emissions from road vehicles may affect the concentrations of principal
pollutants of concern, NO2, PM10 and PM2.5, at sensitive receptors in the vicinity
of the development. Therefore, these pollutants are the focus of the assessment
of the significance of road traffic impacts.
11.2.19. Environmental Protection UK (EPUK) (Ref. 11-13) and the Highways Agency
DMRB guidance set out criteria to establish the need for an air quality
assessment. Both guidance documents consider the changes in traffic
anticipated as a result of development, to identify the need for further evaluation
or assessment. For example, in the DMRB guidance changes in traffic flow of
1,000 AADT (Annual Average Daily Traffic) flow or more, or changes in Heavy
Duty Vehicle (HDV) flows of 200 AADT or more are considered to trigger the
need for further evaluation by quantitative assessment. Where changes in traffic
volumes are less than these criteria, significant changes in air quality are not
expected.
11.2.20. Prior to the construction of the Proposed Development, enabling works will be
undertaken at the Site. The enabling works will include the flood protection
measure to raise sections of the site (the Generating Station Site) by
approximately 2.2m to a maximum of 8.5m AOD. This will involve the importation
of approximately 158,000m3 of material to the Site over the course of 6 months.
During this period, the delivery of material will increase the daily flow of HDVs on
the A403 and A4 by about 342 AADT. During the subsequent 37 month
construction period, the Proposed Development is expected to lead to a
maximum of 80 HDV movements per day.
11.2.21. As such, a screening assessment has been undertaken to estimate the
temporary impact of vehicle movements associated with the land raising on
human receptors. The assessment makes use of the DMRB Screening Method
tool for predicting the quantity of pollutants emitted from vehicle movements.
Vehicle emission rates for 2012 have been used in the tool in combination with
the 2012 background concentration data; this is considered to provide a
conservative estimate of emission rates during the enabling works and
construction phase. The screening assessment has also made use of the NOx to
NO2 conversion spreadsheet updated by Defra since the publication of the
guidance document LAQM.TG(09) (Ref. 11-14), data from Defra pollutant
background maps (Ref. 11-15), URS diffusion tube measurement data, and the
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NO2 with Distance from Road Calculator made available by Defra (Issue 4, Defra,
2011).
11.2.22. The assessment also considers the impact of the construction related vehicle
emissions on the Severn Estuary SPA/SAC/Ramsar and SSSI. Following the
methodology described within the DMRB, the change in annual mean NOX
concentrations and nitrogen deposition rates as a result of construction vehicle
movement emissions has been quantified along a transect across this habitat
site.
Operational Phase
11.2.23. Emissions from the operational Proposed Development have been assessed
following the EPR H1 methodology. Detailed dispersion modelling using the
atmospheric dispersion model ADMS5 has been used to calculate the ground
level concentrations at identified receptors. These concentrations have been
compared with the air quality objectives for each pollutant species. The
assessment has been based on operational design parameters under
consideration for the Proposed Development, as described in Section 11.2.31 to
11.2.37. As mentioned above, the first year of operation of the Proposed
Development is assumed to be 2019 for the purpose of this assessment, which is
the earliest date that the Proposed Development could conceivably start to export
power.
11.2.24. The IED defines ELVs for gas turbines (including CCGTs) for NOX, SO2, CO and
PM10, however emissions of SO2, CO and PM10 from gas-fired plant are at such
low levels that they are considered trivial and, as discussed above, the risk to the
achievement of the CO and SO2 air quality objectives is considered negligible.
These emissions have therefore been screened from further assessment. The
emissions of NO2 have been considered further as there is a potential risk to the
achievement of the objectives identified within the study area.
11.2.25. An assessment of nutrient enrichment (and eutrophication) and acid deposition at
Statutory Habitat sites, featuring sensitive ecological receptors, has been
undertaken following EA guidance AQTAG06 (Ref. 11-16) and using data
obtained from APIS (Ref. 11-17). Non-statutory habitat sites have not been
assessed as the sensitive species present at these receptors and their
associated critical loads for nutrient and acid deposition are not on public records
and no critical levels are available.
Dispersion Model Selection
11.2.26. Dispersion modelling calculates the predicted ground level concentrations arising
from the emissions to atmosphere, based on Gaussian approximation
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techniques. The model employed has been developed for UK regulatory use and
its use in such assessments is approved by the EA.
11.2.27. ADMS5 uses a continuous calculation method to determine the conditions of the
receiving atmosphere based on the Monin-Obukhov length, which represents the
height of the boundary layer and the degree of turbulence within the atmosphere.
This is generally regarded as a more comprehensive modelling approach than
that employed by older models such as ISC, which use discrete approximations
to the atmospheric conditions known as Pasquill stability classes. The degree of
turbulence in the atmosphere affects the rate at which pollutants from point
sources are dispersed in the environment. The more unstable the atmosphere,
for example due to high solar insolation, the greater the degree of mixing. While
this is in principle the desired effect for the release of pollutants through stacks at
elevated heights, this can also lead to localised peak concentrations if the plume
is rapidly brought to ground level.
11.2.28. ADMS5 utilises site-specific hourly sequential meteorological data to enable a
realistic assessment of dispersion from point sources to be conducted for
meteorological conditions that are directly applicable to the site.
11.2.29. Various parameters can affect the degree of dispersion from a source, and these
are accounted for in the modelling scenario where appropriate. The presence of
elevated or complex terrain in the vicinity of the source can affect the flow pattern
of the wind field, which can in turn bring a plume to ground more rapidly.
Buildings of sufficient height located close to the emissions sources can affect
dispersion – inducing downwash in the emitted plume and entraining pollutants
towards ground level.
11.2.30. The detailed model parameters are presented and discussed within Appendix F,
Volume II of this PEI Report. Sensitivity of the predicted concentrations to
variations in these model representations has been undertaken to ensure that the
reported results provide a realistic worst-case assessment. This is again
discussed in Appendix F, Volume II of this PEI Report.
Proposed Development Emission Parameters
11.2.31. Conservative assumptions have been made with regard to operational
parameters, to determine the maximum effects of the operation of the Proposed
Development on sensitive receptors. These assumptions include:
• Maximum potential operational availability for the CCGT units;
• Operation of peaking plant up to 1,500 hours per year at the same time as
the operation of the main units;
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• Maximum emission rates, at IED Emission Limit Values for all combustion
units.
11.2.32. As outlined in Chapter 4: Project Description, the actual hours of operation of the
CCGTs or the peaking plant will be subject to the national demand for electricity
and the economic viability of gas-fired generation, however, it is anticipated that
the CCGTs will operate at an average 31% load factor (an average 2,716 hours
per year) over the course of its lifetime, with the peaking plant expected to run at
a maximum 17% load factor (a maximum 1,500 hours a year).
11.2.33. The existing Seabank 1 & 2 CCGTs have annual average NOx emission
concentrations of approximately half of the IED ELV, and it is considered that the
Proposed Development would operate to a similar level. The above assumptions
of 100% operability and emissions at IED ELVs, should therefore overestimate
the effect on local air quality.
11.2.34. Each CCGT at the Proposed Development will vent to atmosphere via a
dedicated stack. Each peaking plant unit will vent via a dedicated flue, contained
within either individual or common windshields (Ref. 11-18).
11.2.35. As outlined in Chapter 4: Project Description, there are a number of options for
the makeup of the Proposed Development although the overall maximum output
capacity remains fixed at 1,400MWe. Principally these options relate to the
technology selection not being finalised; therefore the two main CCGT units
could be of two different output capacities (700MWe or 580MWe) and could be
constructed in two different configurations (single or multi shaft).
11.2.36. If the lower output capacity units are installed, this allows for the installation of
peaking plant such that the output capacity of the generating station remains at
1,400MWe. At this stage in the project’s development, the Applicant is consulting
on two potential options for the technology of the peaking plant (reciprocating
diesel engines or Open Cycle Gas Turbines (OCGT)) and assessing the impacts
from both options. This provides six potential design configurations for the
Proposed Development that require assessment within this Preliminary
Environmental Information report. The different design schemes configurations
considered within this air quality assessment are detailed in Table 11-4 below.
Table 11-4: Alternative Design Schemes for Combustion Plant
Design
Scheme Units Layout
A 2 x 700 MWe CCGTs (1,400MWe) Single-shaft CCGT
B 2 x 700 MWe CCGTs (1,400MWe) Multi-shaft CCGT
C 2 x 580MWe CCGTs (1,160MWe)
2 x Peaking plant (reciprocating engines) 240MWe Single-shaft CCGT
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Design
Scheme Units Layout
D 2 x 580MWe CCGTs (1,160MWe)
2 x Peaking plant (reciprocating engines) 240MWe Multi-shaft CCGT
E 2 x 580MWe CCGTs (1,160MWe)
2 x Peaking plant (OCGT) 240MWe Single-shaft CCGT
F 2 x 580MWe CCGTs (1,160MWe)
2 x Peaking plant (OCGT) 240MWe Multi-shaft CCGT
11.2.37. The relevant stack and emission parameters for the different units are provided in
Table 11-5.
Table 11-5: Modelled Stack Release Parameters
Parameter
CCGT (single
unit, 700MWe
output)
CCGT (single
unit, 580MWe
output)
Peaking Plant
(Recip
Engines,
240MWe)
Peaking Plant
(OCGT,
240MWe)
Stack Height (m) 90 1
90 45 45
Efflux Velocity (m/s) 22.8 19.6 33.5 34.0
Emission Temperature
(°C) 80 80 371 436
Volumetric Flow (Nm3/hr)
2 3,462,000 2,967,000 1,059,000 832,670
Volumetric Flow at stack
exit parameters (Am3/s)
1,009 865 770 667
Flue Diameter (m) 7.5 7.5 4 5
Assumed maximum
operating hours / year 8,760 8,760 1,500 1,500
NOx ELV (IED, mg/Nm3) 50 50 75.0 51.3
Approximate stack
locations
(354111, 182326)
(354162, 182369)
(354313, 182270)
(354325, 182313)
1 Maximum 98.5m AOD
2 Reference conditions 273K, 0% O2, dry
Sensitive Receptors
Construction Phase
11.2.38. Based on the guidance and assessment criteria presented in Section 11.2, it has
been assumed for the purposes of this assessment that the human health
receptors potentially affected by dust soiling, and short term concentrations of
PM10 generated during construction activities, are limited to those located within
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350m of the nearest construction activity, and/ or within 200m of a public road
used by construction traffic that is within 500m of the construction site entrance,
beyond which distance any track-out would be expected to be minimal.
Ecological receptors have been assumed to be limited to those located within
100m of the nearest construction activity and/ or within 100m of a public road
used by construction traffic that is within 500m of the construction site entrance.
11.2.39. The Proposed Development is located in a predominantly industrial area to the
north of Avonmouth. The nearest receptors that are sensitive to dust soiling and
short term concentrations of PM10 include the neighbouring industrial premises to
the north and south, and the agricultural land to the east. Such receptors are
considered to have a low sensitivity to the effects of dust soiling and increases in
short term emissions of PM10.
11.2.40. The nearest residential receptors to the Proposed Development Site construction
works are Hallen Farm and Stowick Farm, approximately 1.1km from the
Proposed Development Site. The nearest residents to the proposed cooling
water pipeline corridor are approximately 800m from the nearest point of the
corridor. At this distance, the impact of dust soiling and short term concentrations
of PM10 would not be perceptible above background levels. A number of
commercial premises are immediately adjacent to the proposed cooling water
pipeline corridor.
11.2.41. The nearest designated ecological habitat receptor to the Proposed Development
is the Severn Estuary SAC/SPA/Ramsar/SSSI (including Atlantic salt meadows
and transitional communities), which is located approximately 400m from the
Proposed Development Site boundary and 100m from the construction route
(more than 500m from the site entrance). At this distance, the impact of dust
emissions would not be likely to be significant, based on the guidance applied.
11.2.42. Receptors potentially affected by the emissions associated with construction
phase vehicle movements are those located within 200m of a public road used by
construction traffic to access the Site. For this development, it is proposed that
construction vehicles associated with the enabling works will use the A403 and
A4 to the south to access the Site. Sensitive receptors adjacent to this route
include the Severn Estuary to the immediate west of the A403, and residential
properties located on Avonmouth Road (including the AQMA declared by BCC
and designated for NO2) and Portway in Avonmouth to the south of the Site.
Operational Phase
11.2.43. Receptors potentially affected by operational emissions from the Proposed
Development are summarised in Table 11-6 below. The assessment includes the
receptors that are predicted to receive the highest impacts resulting from the
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point source contributions, identified through examination of isopleth figures of
pollutant dispersion. The identified receptors also include designated AQMAs in
the locality.
Table 11-6: Operational Phase – Potential Human Health Receptors
Receptor Sensitive Receptor Type of
Receptor Grid Reference
Distance from
Site (km) and
direction
1 Severn Beach Residential 354400,184150 1.8km north
2 Severn Beach Primary School
School 354190,184690 2.4km north
3 Marsh Common Residential 356500,183400 2.6km northeast
4 Easter Compton Residential 356750,182850 2.7km east
5 Elmore Farm Residential 356000,182300 1.9km east
6 Stowick Farm Residential 354800,180800 1.7km southeast
7 Elmington Manor Farm
Residential 355700,181600 1.8km southeast
8 Berwick Farm Residential 355600,180650 2.3km southeast
9 Hallen Farm Residential 354600,180400 2.0km south
10 Footpaths PROW* 353800,181200 1.0km south
11 Cribbs Causeway AQMA 357760,181425 3.8km east
12 Avonmouth Road/M5 AQMA 352493,177720 4.9km south
*Public Right of Way
11.2.44. Ecological receptors potentially affected by operational emissions include the
Severn Estuary habitat site, of which the most sensitive habitat species type is
listed as Atlantic salt marshes. It is recognised that this most sensitive habitat site
is not located in the immediate vicinity of the Proposed Development site, rather
it is on the Welsh side of the Estuary, however in order to carry out a worst case
assessment, this habitat site has been assumed for the whole of the SSSI.
11.2.45. Statutory designated sites including SSSIs and SACs up to 10km from the
Proposed Development have also been considered, as detailed in Table 11-7
below. No national or local nature reserves have been identified within 2km of the
Proposed Development. The assessment includes the predicted NOX impacts at
the identified ecological receptors and impacts from nutrient nitrogen and acidity
deposition on the Severn Estuary SAC/SPA/Ramsar/SSSI, as this is the
ecological receptor predicted to receive the highest impacts. Details of the sites
and reasons for designations are provided in Chapter 16: Ecology.
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Table 11-7: Statutory Designated Sites of Ecological Interest within 10km of the
Proposed Development Site
Site Distance from Site (km)
and direction Designation
Severn Estuary
(Atlantic salt marshes)
0.4km west (at nearest point)
SAC, SPA, Ramsar site, SSSI
Horseshoe Bend 5.5km south SSSI
Avon Gorge 7.0km south SAC, SSSI
Bushy Close 7.1km northwest SSSI
Gwent Levels – Magor and Undy 7.3km northwest SSSI
River Wye 8.0km north SAC, SSSI
Nedern Brook Wetlands, Caldicot 8.3km northwest SSSI
Weston Big Wood 8.3km southwest SSSI
Ashton Court 9.5km south SSSI
Weston-In-Gordano 9.5km southwest SSSI
Evaluation of Significance
Construction Dust
11.2.46. For potential amenity effects, such those related to dust deposition, the aim is to
bring forward a scheme, to include mitigation measures if necessary, that
minimises the potential for complaints to be generated as a result of the
Proposed Development construction works.
11.2.47. The scale of the risk of adverse effects occurring from each main type of
construction activities, with mitigation in place, is described using the terms high,
medium and low risk. The basis for the choice of descriptor is set out for each
section of the construction works assessment presented below. Experience in the
UK is that good site practice is capable of mitigating the impact of fugitive
emissions of particulate matter effectively, so that in nearly all circumstances,
effects can be controlled to be not significant at the distances identified receptors
are from the Proposed Development site (Ref. 11-11).
11.2.48. Table 11-8 presents the significance criteria for assessing dust effects.
Table 11-8: Descriptors Applied to the Predicted Adverse Effects of Fugitive
Emissions of Particulate Matter
Significance of Effect
at Single Receptor Description
Major A significant effect that is likely to be a material consideration in its own right
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Significance of Effect
at Single Receptor Description
Moderate A significant effect that may be a material consideration in combination with other significant effects, but is unlikely to be a material consideration in its own right.
Minor An effect that is not significant but that may be of local concern.
Negligible An effect that is not significant change.
Operational Emissions
11.2.49. Table 11-9 presents the criteria employed for the determination of the magnitude
of change for gaseous pollutant and PM10 emissions, based on the percentage
increase in pollutant concentrations due to the Proposed Development.
11.2.50. Table 11-10 presents the significance of potential effects, taking into account the
magnitude of change over baseline conditions and the absolute concentration in
relation to air quality objectives. Particular significance should be given to a
change that takes the concentration from below to above the NAQS objective or
vice versa because of the importance ascribed to the objectives in assessing
local air quality.
11.2.51. Table 11-9 has been modified slightly from the criteria presented in the EPUK
guidance to accommodate the terms High to Very Low for magnitude of change
and the terms ‘Major’, ‘Moderate’ and ‘Minor’ in relation to significance of effect,
as described in Chapter 7: Assessment Methodology, to ensure consistency with
other assessment chapters within this report.
Table 11-9: Determination of Magnitude of Change – Air Quality
Magnitude of
change
Annual Mean Process Contribution
Concentration NO2 and PM10 (µg/m³) Days PM10 >50µµµµg/m
3
High Increase/decrease >4 (>10%) Increase/decrease >4
Medium Increase/decrease 2 – 4 (5-10%) Increase/decrease 2 - 4
Low Increase/decrease 0.4 – 2 (1-5%) Increase/decrease 1 - 2
Very Low Increase/decrease < 0.4 (<1%) Increase/decrease <1
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Table 11-10: Significance of Effects
Absolute Concentration (Predicted
Environmental Concentration - PEC) in
Relation to Objective/Limit Value
Change in Concentration
High Medium Low Very Low
Increase with Proposed Development
Above Air Quality Standard or Guideline with the Proposed Development (>40 µg/m
3,
>100%)
Major Adverse
Moderate Adverse
Minor Adverse
Negligible
Just Below Air Quality Standard or Guideline with the Proposed Development (36 - 40 µg/m
3, 90-100%)
Moderate Adverse
Moderate Adverse
Minor Adverse
Negligible
Below Air Quality Standard or Guideline with the Proposed Development (30 - 36 µg/m
3,
75-90%)
Minor Adverse
Minor Adverse
Negligible Negligible
Well Below Air Quality Standard or Guideline with the Proposed Development (<30 µg/m
3,
<75%)
Minor Adverse
Negligible Negligible Negligible
Decrease with Proposed Development
Above Air Quality Standard or Guideline with the Proposed Development (>40 µg/m
3,
>100%)
Major Beneficial
Moderate Beneficial
Minor Beneficial
Negligible
Just Below Air Quality Standard or Guideline with the Proposed Development (36 - 40 µg/m
3, 90-100%)
Moderate Beneficial
Moderate Beneficial
Minor Beneficial
Negligible
Below Air Quality Standard or Guideline with the Proposed Development (30 - 36 µg/m
3,
75-90%)
Minor Beneficial
Minor Beneficial
Negligible Negligible
Well Below Air Quality Standard or Guideline with the Proposed Development (<30 µg/m
3,
<75%)
Minor
Beneficial Negligible Negligible Negligible
11.2.52. The evaluation of significance of the impacts associated with process emissions
has been based on the criteria outlined in the EA EPR H1. This indicates that for
the assessment of point source emissions, long term ground level pollutant
concentrations resulting from point source emissions which are less than 1% of
an NAQS objective can be treated as insignificant (or negligible). Similarly, short
term ground level pollutant concentrations resulting from point source emissions
which are less than 10% of an NAQS objective can also be treated as
insignificant (or negligible). Where emissions are not screened as negligible, the
descriptive terms for the significance of the effect, outlined in Table 11-11, have
been applied.
11.2.53. The significance of effects of point source emissions on ecological receptors,
through deposition of nutrient nitrogen or acidity, has been evaluated using the
EA insignificance criterion of 1% of the long term critical level objective, as
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above, in the absence of any specific guidance. At this stage no evaluation of
contribution to critical loads has been undertaken; the need for this will be
considered following Stage 2 consultation and, if required, included in the final
ES.
Key Parameters for Assessment
Construction Phase
11.2.54. The Rochdale Envelope parameters do not significantly affect the input
parameters utilised in the construction air quality assessment, and
consequentially the outcome of this assessment will not vary under the Envelope
applied. Therefore, no further discussion of the Rochdale Envelope parameters is
provided in relation to construction phase effects and the assessment adopts
conservative (worst case) values where assumptions are necessary.
Operational Phase
11.2.55. The key parameters for the assessment of air quality effects from the Proposed
Development operational phase are considered to be:
• Selection of technology for combustion processes with influence on NOx
emissions to air in particular;
• Building heights and layouts associated with the combustion technology;
and,
• Stack heights.
11.2.56. At this design stage, the specific technology, and hence the final combustion
emission parameters, have not been fixed. The air quality effects have therefore
been based on the maximum (worst-case) parameters. This is discussed in detail
in Appendix F, Volume II of this PEI Report.
11.3. Baseline Conditions
11.3.1. This section discusses the existing conditions and secondary and primary data
collection.
Publicly Available (Secondary) Air Quality Data
11.3.2. Baseline air quality conditions in the vicinity of the Proposed Development Site
have been evaluated through a review of local authority air quality management
reports, Defra published data, and other sources. As previously described, the
key pollutants of concern resulting from construction and operation of the
Proposed Development are NO2, CO, PM10 and PM2.5, therefore the assessment
of baseline conditions considers these pollutants only.
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Local Air Quality Management
11.3.3. The statutory review and assessment of local air quality by SGC in 2010 resulted
in designation of three AQMAs for the potential to exceed the annual NO2 NAQS
objective, of which the closest, Cribbs Causeway adjacent to the M5, is 4km east
of the Proposed Development Site. Revocation of the Cribbs Causeway AQMA
was recommended by SGC in a further assessment undertaken in 2011,
however this was not agreed by Defra and the AQMA designation still currently
stands.
11.3.4. The statutory review and assessment of local air quality within the area by BCC
resulted in the designation of an AQMA for Bristol city centre and main radial
roads for the potential to exceed the annual NO2 and annual PM10 NAQS
objectives, as a precautionary measure. An additional small area, where
Avonmouth Road is crossed by the M5, is in the process of being designated an
AQMA for NO2. The Proposed Development Site is 5km north of Avonmouth
Road AQMA and 7.5km northwest of the Bristol AQMA, along the A38.
11.3.5. Monitoring undertaken by SGC and BCC includes a number of continuous
monitoring stations (including NO2 and PM10) and a network of NO2 diffusion
tubes, covering background sites and also sites representative of exposure for
sensitive receptors. Monitoring data from these automatic and non-automatic
sites in the area are presented in Table 11-11 below for 2012 (the most recent
year’s ratified data available at the time of writing).
Table 11-11: Ambient Data from Local Authority Secondary Sources
Authority Type Location Location
from site
Data
Capture
(%)
2012
NO2
(µg/m3)
2012
PM10
(µg/m3)
2012
SGC Automatic (UB)
Filton – Conygre House
7.3km SE
96.8 20 18
Automatic (R)
Yate – Station Road
16.3km E
90.3 27
24
Diffusion tube (UB)
Severn beach primary school
2.3km N
100 17.6 -
Diffusion tube (RF)
Cribbs Causeway – Blackhorse Hill Hollywood Cottage
3.9km E
100 35.0 -
BCC Diffusion tube (RF)
Avonmouth Rd (in AQMA)
4.9km SW
100 34.7 -
Diffusion tube (RF)
Avonmouth Rd (in AQMA)
4.9km SW
90 34.0 -
Diffusion tube (RF)
Avonmouth Rd (in AQMA)
4.9km SW
100 31.8 -
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Authority Type Location Location
from site
Data
Capture
(%)
2012
NO2
(µg/m3)
2012
PM10
(µg/m3)
2012
Automatic (UB)
St.Pauls AURN (in Bristol AQMA)
10.1km SE
98.6 31.5
Notes: UB =Urban Background, R=Roadside, RF=Roadside Façade
11.3.6. The nearest current automatic monitoring station is located at Filton, 7.3km
southeast of the Proposed Development Site, in an urban location which would
be expected to experience typically higher NO2 contributions from road traffic
than the rural and semi-rural areas likely to be impacted by emissions from the
Proposed Development.
11.3.7. There are no sources of monitored PM10 or PM2.5 data in the Avonmouth area. In
the absence of monitored data, baseline PM10 and PM2.5 conditions are
represented by the Defra background maps (see below).
11.3.8. Historic NO2 monitoring undertaken in 2007 around Seabank 1 & 2 has also been
provided by BCC. This monitoring included a number of diffusion tube sites along
the estuary road to the west of the Proposed Development Site and adjacent to
the Severn Estuary SAC/SPA/Ramsar/SSSI. An automatic monitor was also
located at Almondsbury, an area broadly representative of rural receptors to the
northeast of the Proposed Development. The most recent year’s data (2007)
obtained from this monitoring campaign is provided in Table 11-12.
Table 11-12: Historic Ambient NO2 Monitoring Data
Type Location Grid Ref (x,y) Location
from Site
NO2 (µg/m3)
2007
Diffusion tube Holesmouth, adjacent to fuel depot and rail-line
352107, 180804 2.5km SW 36
Diffusion tube Chittening Warth, background location
353511, 182902 0.8km W 22
Diffusion tube Severn Beach, background location
353710, 183826 1.5km N 24
Automatic (UB) Almondsbury School 360270, 183962 6.4km NE 16.4
11.3.9. The 2007 data from background diffusion tube monitoring locations at Severn
Beach and Chittening Warth, which are only 800m and 1.5km west of the
Proposed Development Site, are higher than the automatic monitoring data but
are likely to have been influenced by the adjacent former ICI/Terra Nitrogen
works that were operational until 2008.
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Defra Published Data
11.3.10. Defra published maps of background air quality concentrations indicate that NOx
and NO2 concentrations within the surrounding area vary considerably depending
on the local contributory sources. For example the area to the north of Seabank 1
& 2, near to the Severn Road, has much higher NOx than the open areas to the
south. The range of concentrations away from the industrial areas at Chittening is
15-17µg/m3. The mapped data has therefore been obtained for the locations of
likely maximum impact from emissions from the Proposed Development and are
shown in Table 11-13. Projected concentrations for 2019 are also provided.
Table 11-13: Defra Mapped Background Data (1km grid squares)
Receptor Grid Ref.
NO2
(µg/m3)
NOx
(µg/m3)
PM10
(µg/m3)
PM2.5
(µg/m3)
2012
Human Health (downwind of Proposed Development)
355500, 182500
16.6 24.1 14.7 9.4
Human Health, Avonmouth AQMA 352500, 178500
26.5 - 18.0 12.5
Severn Estuary SSSI (N of Seabank 1&2)
353500, 183500
23.7 37.7 - -
Severn Estuary SSSI (W of Seabank 1&2)
353500, 182500
14.9 21.3 - -
Severn Estuary SSSI (SW of Seabank 1&2)
352500, 181500
13.8 19.6 - -
2019
Human Health (downwind of Proposed Development)
355500, 182500
13.3 18.7 14.2 8.9
Human Health, Avonmouth AQMA 352500, 177500
21.6 - 16.7 11.1
Severn Estuary SSSI (N of Seabank 1&2)
353500, 183500
20.1 30.7 - -
Severn Estuary SSSI (W of Seabank 1&2)
353500, 182500
12.1 16.9 - -
Severn Estuary SSSI (SW of Seabank 1&2)
352500, 181500
11.4 15.8 - -
Existing Particulate Sources
11.3.11. A background level of dust exists in all urban and rural locations in the UK. Dust
can be generated on a local scale from vehicle movements and from the action of
wind on exposed soils and surfaces. Dust levels can also be affected by long
range transport of dust from distant sources into the local vicinity.
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11.3.12. Receptors currently experience dust deposition at a rate that is determined by the
contributions of local and distant sources. This baseline rate of soiling varies
dependent on prevailing climatic conditions and works being undertaken in the
area. The tolerance of individuals to deposited dust is typically shaped by their
experience of baseline conditions.
11.3.13. Existing local sources of particulate matter include industrial emissions from
nearby facilities, agricultural emissions form the farmland to the east, exhaust
emissions and brake and tyre wear from road vehicles and the long range
transport of material from outside the study area.
Existing and Proposed Industrial Combustion Sources
11.3.14. Existing industrial sources of emissions to air that are likely to have a significant
influence on local air quality include Seabank 1 & 2 to the immediate west of the
Proposed Development. It is considered that emissions from Seabank 1 & 2 have
been taken into consideration in the interpretation of the baseline data, as
discussed in the Section below.
11.3.15. Proposed industrial sources of emissions to air that could influence local air
quality in the vicinity of the Proposed Development have been identified and are
described in Section 11.7 – Cumulative Effects Assessment.
Primary Data Gathering – Diffusion Tube Monitoring
11.3.16. Additional diffusion tube monitoring has been undertaken by the Applicant in the
vicinity of the Proposed Development Site to provide more data on the
background air quality in this location and to supplement the publicly available
data. A total of seven locations were agreed with SGC, BCC and the EA to
monitor concentrations of NO2 and NOX. These locations are described in Table
11-14 and illustrated in Figure 11-1 (Volume III).
Table 11-14: Primary Diffusion Tube Monitoring Locations
Ref. Location Grid Ref. Description Located
1 Seabank 3 354215, 182429 Urban background site, avoiding location downwind of Seabank stacks, >100m from road.
Fence
2 Seabank 1 & 2 353420, 182578 Urban background site, avoiding location downwind of the existing stacks >100m from road.
Fence
3 Severn Way Mobile Phone Mast
353330, 182621 >5m and upwind of road, relevant exposure for SSSI.
Fence/ Lamppost
4 Background location
353718, 183504 Relevant exposure for SSSI, >100m from road, no nearby significant sources.
Fence
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May 2014 Page 11-24
Ref. Location Grid Ref. Description Located
5 Severn Beach Primary School
354192, 184687
Urban background site, duplicate to SGC tube, representative of likely long term maximum impact at SSSI from Proposed Development operations.
Lamppost
6 Marsh Common, Pilning
356509, 183394 >5m from road, relevant exposure for residential receptors.
Lamppost
7 Brook Farm, Vimpenny's Lane
356260, 182060 Residential receptor, >200m from M5 motorway.
Lamppost
11.3.17. Three months of data have been gathered, with the diffusion tubes deployed for a
month at a time, thereby providing three results over the sampling period. The
average diffusion tube results across the three samples are presented in Table
11-15 below. The data has been annualised using data from Bristol St. Pauls,
Chepstow and Newport (June-Sept, 2013) and bias adjusted (Gradko, 09/13).
Table 11-15: Mean monitored Concentrations, 4 June - 30 Sept 2013 (µg/m3)*
Ref. Location Mean NO2
(µg/m3)
Mean NOx
(µg/m3)
1 Seabank 3 (UB) 22.6 23.9
2 Seabank 1 & 2 (UB) 23.3 26.8
2a Seabank 1 & 2 (duplicate) (UB) 22.0 28.1
3 Severn Road Mobile Phone Mast, adjacent to the road (R)
37.7 50.8
4 Background location, adjacent to Severn Estuary SSSI (UB)
19.8 22.1
5 Severn Beach Primary School (UB) 25.4 35.4
6 Marsh Common, Pilning (R) 25.8 33.9
7 Brook Farm, Vimpenny's Lane (UB) 20.3 25.2
* Note – Annualisation factors: NO2 1.37, NOx 1.41
Bias adjustment factor 0.96 (Gradko, 09/13).
11.3.18. The average measured NO2 concentration across all diffusion tubes deployed is
22.7µg/m3 (excluding 1 outlier) which meets the annual mean NAQS objective.
The outlier at Location 3, shows an NO2 concentration of 37.7µg/m3, and is
significantly above the average, however this monitoring location is less than
10m from the A403 (Severn Road) and the railway line, and within 5m of a lay-by
regularly used by HGVs; it is not considered to be a true background location.
The nearest comparable monitoring location away from the roadside is Location
1 at Seabank 1 & 2, 100m from Location 3, which shows considerably lower NO2
and NOx concentrations. This supports the opinion that Location 3 may be
experiencing higher concentrations as a result of road traffic sources and also
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May 2014 Page 11-25
idling vehicles in the lay-by, which were observed during collection and
redeployment of the tubes. The contribution of vehicle emissions to local air
quality conditions drops rapidly with distance from the road (typically to
background levels within 200m of the road source (Ref 11-9)), which is supported
by the diffusion tube data. SGC and BCC have provisionally agreed that Location
3 is not representative of background concentrations.
Derivation of Baselines used in the Assessment
11.3.19. The construction phase and operational phase of the Proposed Development are
anticipated to impact upon different receptor locations, with the construction
impacts concentrated locally to the Site and along the A403 and A4 for
construction traffic; whereas the operational impacts will be dominated by point
source emissions with long term impacts in the prevailing wind direction to the
northeast of the Proposed Development (towards Easter Compton and Marsh
Common) and peak short term impacts occurring locally to the Site. The
background concentrations have been derived for these receptor locations and
phases and are summarised in Table 11-16 below.
NO2 – Human Health Impacts
11.3.20. The baseline data available within the principal study area indicates that annual
mean concentrations of NO2 are typically well below the NAQS objective at
sensitive human health receptor locations. The diffusion tube results (excluding
the outlier) indicate that the background NO2 concentration in the site vicinity is
19-23µg/m3, and this data is supported by the nearest current automatic
monitoring station at Filton (20µg/m3) and historic monitoring. The Defra
background gridded data indicate typically lower background concentrations than
those from the diffusion tubes (around 17µg/m3), as would be expected from data
averaged over a 1km2 scale. The long term NO2 concentration in the study area
at key human health receptor locations is therefore assumed to be 23µg/m3 in
2012 and 18µg/m3 in 2019, for a conservative assessment of annual average
impacts. Short term impacts have been assessed assuming twice the long term
average background concentration in accordance with EA H1 guidance.
11.3.21. The assessment of peak construction traffic effects on the Avonmouth AQMA has
assumed baseline air quality derived from Defra mapping for this location. DMRB
has been used to estimate the NO2 concentration at the façade of the buildings
and therefore to verify the concentration against diffusion tube data. The 2012
value obtained using a Defra background of 28µg/m3 was 35-36µg/m3 which
compares well with the BCC diffusion tube monitoring data of 34-35µg/m3 at
these locations.
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NOX – Ecological Impacts
11.3.22. The construction traffic assessment of effects on the Severn Estuary habitat site
has assumed the background NOx concentrations based on the Defra gridded
data for the grid squares containing this habitat site along Chittening Warth (as
shown in Table 11-13). The marked difference between the baseline
concentrations in areas north and west of the Proposed Development (a
difference of 10µg/m3 NO2) is assumed to be principally the result of road traffic
and existing industrial and commercial sources, including Seabank 1 & 2 and
commercial developments north of the Proposed Development Site; these
sources have therefore been taken into account in the baseline of the air quality
assessment.
11.3.23. Two ecological receptor locations have been assessed for traffic impacts, based
on the higher concentration (north) and lower concentration (southwest) from
Defra gridded baseline data.
11.3.24. The reduction in NO2 concentrations, as the result of anticipated improvements in
UK national vehicle fleet year on year, has been assumed up to the traffic
assessment for peak construction year (2017).
11.3.25. Three ecological receptor locations have been assessed for the assessment of
operational plant emissions, representing locations north, west and southwest of
the Proposed Development Site.
11.3.26. The 2019 baseline NOx concentration has also been used for the point source
assessment as a conservative assumption, although Defra projections indicate
that this concentration should reduce further by the opening operational year of
the generating station.
Particulates
11.3.27. Filton automatic monitoring station, located 7km southeast of the Proposed
Development Site is the nearest automatic monitor to the Proposed Development
and has recorded relatively stable PM10 concentrations for the last five years,
between 17-20µg/m3, which are well below the annual NAQS objective. Defra
gridded data for the potential receptors of emissions from the Proposed
Development indicates that baseline PM10 and PM2.5 are well below their
respective national air quality objectives of 40µg/m3 and 25µg/m3. The Defra
values, as detailed in Table 11-13, have been assumed for assessment of point
source and traffic impacts at the worst case receptors.
11.3.28. Table 11-16 presents a summary of the derived baseline concentrations for each
type of receptor and phase of development used in the assessment.
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Table 11-16: Derived Baseline Concentrations (µg/m3)
Pollutant Receptor Source Baseline Concentration
2012 2019
NO2 Human health – AQMA
Construction traffic 26.5 21.6
NO2 Human health – AQMA
Operation 35.0 35.0
NO2 Human health Operation 23.0 18.1
NOX Ecological - north Operation, Construction traffic
37.7 30.7
NOX Ecological - west Operation, Construction traffic
20.9 16.9
NOX Ecological – south west
Operation, Construction traffic
19.6 15.8
PM10 Human health Construction traffic 18.0 16.7
PM10 Human health Operation 14.7 14.1
PM2.5 Human health Construction traffic 12.5 11.1
PM2.5 Human health Operation 9.4 8.9
Deposited Nitrogen
11.3.29. Based on the above data, the baseline NOx concentrations and nitrogen
deposition rates have been predicted using the DMRB tool at the transect of the
Severn Estuary SPA/SAC/Ramsar/SSSI for each of the two traffic assessment
locations, and are provided in Table 11-17. The baseline data is presented for
2019, the earliest year that the Proposed Development could reasonably be
commissioned.
Table 11-17: Predicted Baseline NOx Concentrations and Nitrogen Deposition Rates
at the Severn Estuary, 2019
Distance from A403 (m)
2019 Annual Mean NOx (µg/m
3)
2019 Nitrogen Deposition Rate (kg N/ha/yr)
North South-west
North (based on maximum)
South-west (based on
mean)
25 44.9 30.0 21.2 10.5
30 43.2 28.3 21.1 10.5
40 40.4 25.5 21.0 10.4
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Distance from A403 (m)
2019 Annual Mean NOx (µg/m
3)
2019 Nitrogen Deposition Rate (kg N/ha/yr)
North South-west
North (based on maximum)
South-west (based on
mean)
50 38.3 23.4 21.0 10.3
75 34.9 20.0 20.9 10.2
100 33.0 18.1 20.8 10.1
Assessment Criteria
30 20 – 30
11.3.30. Baseline NOx conditions at some sections of the Severn Estuary
SPA/SAC/Ramsar/SSSI within 100m of the A403 are predicted to exceed the
CLPVE of 30µg/m3, in 2019.
11.3.31. The maximum nitrogen deposition rate at this habitat site (according to APIS) in
2012 was 24.8kg N/ha/yr and the mean was 12.0kg N/ha/yr. In recognition of the
higher baseline atmospheric NOX and NO2 concentrations at the northern
ecological assessment location, the higher deposition rate has been assumed for
this location. This is a conservative assumption however, as the APIS reported
rate of deposition (which covers the entire area of the SSSI designation) does not
correlate with the Defra ambient data. The APIS rate of nitrogen deposition is
well below the upper critical load threshold for a salt marsh habitat.
11.4. Development Design and Impact Avoidance
IED Emission Limit Value (ELV) Compliance
11.4.1. The Proposed Development has been designed such that process emissions to
air will comply with the ELVs specified in the IED. This will be enforced by the EA
through the Environmental Permit required for the operation of the generating
station.
Stack Height
11.4.2. The stack height has been optimised with consideration given to minimisation of
ground level air quality impacts, and visual impacts of a taller stack. Preliminary
dispersion modelling was undertaken to determine the optimum stack height
range and local residents informally consulted regarding their preference. Further
information on the determination of the stack height is provided in the Appendix
F, Volume II of this PEI Report.
11.4.3. The selected stack height has been incorporated into the plant design and is
based on a specified value of 90m above the finished ground level (up to 98.5m
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May 2014 Page 11-29
AOD) for the CCGT units and 45m (up to 53.5m AOD) for the peaking plant
stacks; therefore if the buildings onsite reduce in size from the maximum
permitted heights and dimensions modelled in this assessment, the stack heights
would remain at 90m and therefore benefit from reduced building effects and
associated increased dispersion.
Stack Locations
11.4.4. The proposed locations of the main CCGT stacks are shown in Table 11-5
above. The exact locations cannot be specified as they are dependent on the
technology configuration selected for the Proposed Development.
11.4.5. The proposed locations of the peaking plant and its stacks were modified during
the design evolution, as outlined in Chapter 6: Project Need and Alternatives,
when preliminary dispersion modelling demonstrated that a lower stack height
and lower offsite effects could be achieved by moving this plant further from the
HRSG buildings.
Visible Plumes
11.4.6. The potential for visible plumes from the CCGT main stacks is considered very
low as a result of the water content and temperature of the flue gas. The Large
Combustion Plant BREF Note (Ref 11-7) states that plume visibility can be
reduced by maintaining stack release temperatures above 80°C, which is the
current design intention for the Proposed Development.
11.4.7. Visible plumes from the proposed hybrid cooling water systems have not been
assessed, as they are not expected to generate a visible plume under most
meteorological conditions. The hybrid cooling water systems are also relatively
low in height – around 19m above the finished ground level. Given the distances
to sensitive receptors the risk of potential nuisance from visible hybrid cooling
water system plumes is considered negligible.
11.5. Potential Effects and Mitigation Measures
Construction Phase
Assessment of Construction Dust
11.5.1. The nearest receptors to the Site boundary are the local industrial properties to
the north and southwest, and the agricultural land to the east. There are no dust
sensitive residential or ecological receptors within 500m of the construction site
boundary, for either the Proposed Development or proposed cooling water
pipeline corridor. There are a number of commercial receptors adjacent to the
proposed cooling water pipeline corridor, such as warehouses and distribution
yards, as well as the Seabank 1 & 2 generating station adjacent to the Proposed
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Development Site; however these are not considered sensitive to construction
dust.
11.5.2. Prior to the main construction works, enabling works will be undertaken, which
will include the ground levelling work, the diversion of utilities, and the land
raising of the Generating Station site.
11.5.3. The potential impacts considered at the sensitive receptor locations are:
• Effects on amenity and property including changes to the rate of
deposition of particulate matter onto surfaces; and
• Changes in 24-hour mean airborne particulate concentrations that might
increase the risk of exposure to PM10 at levels that could exceed the 24-
hour air quality objective.
11.5.4. The significance of impacts on sensitive receptors has been informed by IAQM
Guidance (Ref 11-11). The assessment has assumed that standard construction
dust mitigation measures will be applied onsite, in accordance with the best
practice.
11.5.5. The predicted impacts at the nearest sensitive receptors have been considered
for each of the following activities:
• Earthworks;
• Construction works; and,
• Track-out (the deposition of material on local roads from construction
related vehicle movements).
11.5.6. There are no demolition works anticipated as part of the Proposed Development
scheme.
Earthworks
11.5.7. The earthworks associated with the Proposed Development will entail the storage
and handling of the material imported to Site for the raising of part of the Site for
flood protection, the excavation and handling of material for the diversion of
utilities and the trench for the cooling water pipeline, the earthworks associated
with piling and foundations, and those associated with the final landscaping of the
Site.
11.5.8. Earthworks are generally considered to be a high risk activity with regard to the
generation of dust, due to the mechanical nature of the activities involved and the
manipulation of potentially dusty material. The earthworks undertaken within the
Proposed Development Site boundary will take place within 50m of industrial
receptors and neighbouring agricultural land. The earthworks undertaken for the
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installation of the cooling water pipeline will also take place within 50m of
industrial receptors and neighbouring agricultural land, as well as commercial
premises. Of the receptors in close proximity to the works, the car distribution
yard is considered the most sensitive to such impacts and therefore has been
considered further below.
11.5.9. Industry standard dust and particulate mitigation measures will be applied to
control the release of emissions during the earthworks elements of the enabling
and construction works. Such measures are standard practice on all well
managed construction sites and will be implemented through a CEMP to be
prepared by the appointed construction contractor for the works. They may
include, but would not be limited to the following:
• The resurfacing or refilling of earthworked and exposed areas at the
earliest opportunity;
• The provision of a water supply for dust suppression for use during high
risk earthworks activities;
• Ensuring that the slopes of material stockpiles are no steeper than the
natural angle of repose of the material and maintain a smooth profile; and
• Avoiding the double handling of potentially dusty material.
11.5.10. With the implementation of good site practice and the stringent use of dust
control measures throughout the earthworks elements of the enabling and
construction works, based on the IAQM guidance, it is anticipated that there
would be a small, temporary increase in the rate of dust soiling. For the
installation of the cooling water pipeline close to the car distribution yard for
example, the duration of works is envisaged to be less than 4 weeks. Such an
increase is anticipated to have a temporary, reversible, minor adverse effect on
receptors.
Construction
11.5.11. The construction work activities associated with the Proposed Development will
entail the erection of structures for the Generating Station and Peaking Plant.
The construction of these structures will mainly be undertaken using pre-
fabricated materials and there will be a minimal requirement to cut and grind
construction materials onsite.
11.5.12. Industry standard dust and particulate mitigation measures will be applied to
control the release of emissions during the construction works. Such measures
are standard practice on all well managed construction sites and will be
implemented through the CEMP to be prepared by the appointed construction
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contractor for the works. These may include, but would not be limited to the
following:
• Any onsite cement batching will be undertaken in a designated area that
where possible is shielded and located away from the most sensitive
receptors nearby;
• Locating potentially dust generating activities away from the most
sensitive receptors nearby, where possible; and,
• The provision of a water supply for suppression for use during high risk
construction activities.
11.5.13. With the implementation of good site practice and the stringent use of dust
control measures throughout the construction works, it is anticipated that there
would be a negligible impact on the rate of dust soiling and a negligible impact on
short-term concentrations of PM10 and a negligible effect on receptors.
Track-out
11.5.14. During the construction phase, construction-related vehicle movements will
access and leave the Proposed Development Site via a proposed Spine Access
Road which Severnside Distribution Land Ltd is currently constructing under the
extant 1957/58 consent. The new road will connect to the A403.
11.5.15. Access/ egress for the proposed cooling water pipeline corridor is expected at
several locations along the length of the corridor, for example where the pipeline
crosses a road access will be sought from along the affected road.
11.5.16. Based on IAQM guidance, there is the potential for dust associated with track-out
to impact upon sensitive receptors located within 100m of roads that extend up to
500m from the construction site entrance. Receptors within 100m of the new
Spine Access Road include the surrounding industrial premises and nearby
agricultural land.
11.5.17. Standard dust and particulate mitigation measures, as described within current
construction dust guidance, will be applied to control the release of emissions
from track-out during the enabling and construction works. Such measures are
standard practice on all well managed construction sites and will be implemented
through the CEMP to be prepared by the appointed construction contractor for
the works. These measures may include, but would not be limited to the
following:
• The hard-surfacing and effective cleaning of main onsite haul routes and
the enforcement of appropriate site speed limits;
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• Routinely cleaning sections of the public road network near to the site
entrance, using wet sweeping methods; and
• Covering or sheeting vehicles entering and leaving the site that are
loaded with potentially dusty material.
11.5.18. With the implementation of good site practice and the stringent use of dust
control measures throughout the construction works, it is anticipated that track-
out would have a negligible impact on the rate of dust soiling and a negligible
impact on short-term concentrations of PM10; such an impact is anticipated to
have negligible effect on receptors.
Summary
11.5.19. The predicted impact of enabling and construction activities on nearby receptors
during the construction of the Proposed Development are summarised in Table
11-18. Overall the impact of the Proposed Development would result in
negligible effects or temporary, reversible, minor adverse effects for dust
deposition on sensitive receptors.
Table 11-18: Summary of Construction Phase Dust Effects
Source Effects on Amenity and Property Exposure to PM10 at Levels that could Exceed the 24-hr Mean PM10 Air Quality Objective
Demolition N/A N/A
Earthworks Temporary, Reversible, Minor Adverse
Negligible
Construction Negligible Negligible
Track-out Negligible Negligible
Assessment of Construction Road Traffic
11.5.20. The enabling works associated with raising the level of the Proposed
Development Site will increase HDV movements by up to an estimated 342
vehicles per day. Based on DMRB screening calculations, the predicted impact of
the emissions of these vehicle movements to annual mean NOX concentration
and the nitrogen deposition rate at the Severn Estuary habitat site is summarised
in Table 11-20.
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-34
Table 11-19: Predicted With-Development NOX Concentrations and Nitrogen Deposition Rates
at the Severn Estuary SAC/SPA/Ramsar/SSSI in 2019
Distance
from A403
(m)
Annual
Mean NOx
(µg/m3)
Change in
Annual Mean
NOx (µg/m3)
Significance
of change in
annual mean
NOx
Nitrogen
Deposition
Rate
(kg N/ha/yr)
Change in N-
Deposition
Rate
(kg N/ha/yr)
North of the Proposed Development Site
25 46.3 +1.4
(<5% Increase) Minor adverse 21.2
+0.04 (<1% Increase)
30 44.4 +1.2
(<5% Increase) Minor adverse 21.2
+0.03 (<1% Increase)
40 41.4 +0.9
(<5% Increase) Minor adverse 21.1
+0.03 (<1% Increase)
50 39.1 +0.7
(<5% Increase) Minor adverse 21.0
+0.02 (<1% Increase)
75 35.3 +0.4
(<5% Increase) Minor adverse 20.9
+0.01 (<1% Increase)
100 33.2 +0.2
(<1%) increase Negligible 20.8
+0.01 (<1% Increase)
Southwest of the Proposed Development Site
25 31.4 +1.4
(<5% increase) Minor adverse 10.6
+0.04 (<1% Increase)
30 29.5 +1.2
(<5% increase) Minor adverse 10.5
+0.03 (<1% Increase)
40 26.5 +0.9
(<5% increase) Negligible 10.4
+0.03 (<1% Increase)
50 24.2 +0.7
(<5% increase) Negligible 10.4
+0.02 (<1% Increase)
75 20.4 +0.4
(<5% increase) Negligible 10.2
+0.01 (<1% Increase)
100 18.3 +0.2
(<1%) Negligible 10.2
+0.01 (<1% Increase)
Criteria 30 20 – 30
11.5.21. The peak construction traffic emissions are predicted to lead to a small increase
in annual mean NOX concentrations at the Severn Estuary
SAC/SPA/Ramsar/SSSI within 100m of the A403, with the greatest increases at
locations within 25m of the A403. It is important to note that this is based on an
assessment of annual impact against annual assessment criteria, whereas the
importation of material for land raising is expected to only last for a period of six
months. The assessment is therefore an overestimate of potential impact.
11.5.22. As outlined above, the Severn Estuary SAC/SPA/Ramsar/SSSI is already
predicted to experience concentrations of NOX in excess of the CLPVE to the
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-35
north of the Proposed Development in 2019, with or without the Proposed
Development. The increase as a result of the Proposed Development
construction traffic is therefore considered a minor adverse effect at this
location. However locations to the west and southwest are predicted to
experience annual mean NOX concentrations well below the CLPVE and
therefore the increase is considered to have negligible effect for all but those
locations within 30m of the A403. The impacts from construction traffic will be
temporary and therefore the effect of the increased NOX is considered to be
temporary and reversible.
11.5.23. The rate of nitrogen deposition will also increase as a result of the construction
vehicle movements associated with the enabling works. With this increase,
assuming the baseline is at the maximum and average deposition rates reported
for this habitat for locations north and southwest of the Site respectively, the rate
of deposition remains well below the upper threshold of the critical load for this
habitat. The effect of increased nitrogen deposition at the Severn Estuary
SAC/SPA/Ramsar/SSSI as a result of construction traffic is therefore considered
to be negligible.
11.5.24. The enabling works are scheduled to last for a period of approximately 12
months, with the vehicle trips associated with land raising assumed to be
compressed into a 6 month period. Upon completion of those works, construction
traffic will fall to levels of around 80 HDV movements per day. As such, the
annual mean NOX concentrations reported in Table 11-19 represent a worst-case
period and concentrations will fall closer to baseline levels on completion of the
earthworks associated with the enabling works.
11.5.25. A screening assessment has been undertaken to estimate the impact of
construction traffic on human air quality sensitive receptors located adjacent to
the A403 and the A4. The DMRB Screening Method Spreadsheet was used to
predict the road NOX and PM10 contributions to annual mean concentrations at a
location 10m from the centreline of the road, which is representative of the
nearest sensitive receptors locations to the A403 and the A4. The road NOX
contribution was then converted into an annual mean road NO2 contribution using
Defra’s NOX to NO2 conversion spreadsheet.
11.5.26. The 342 HDV movements associated with the land raising element of the
enabling works would increase annual mean concentrations of NO2 by 1.6µg/m3
and annual mean concentrations of PM10 by 0.2µg/m3 at the worst affected
residential receptors. Such an increase in pollutant concentrations, on top of the
baseline concentrations described in Section 11.4, would lead to an impact of low
magnitude in an area where air quality is well below the NAQS objectives for
those pollutants. The proportion of particulate matter emissions that are PM2.5 is
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-36
included within the PM10 contribution of 0.2µg/m3. An increase of less than
0.2µg/m3 in an area where background concentrations are well below the NAQS
objective is considered to be insignificant. The effect of such impacts is therefore
considered to be negligible.
11.5.27. The impact of HDV movements on the AQMA at Avonmouth Road has been
assessed assuming as a worst-case that all HDVs use this route. In reality, the
HDVs are more likely to use the A4/Portway. The predicted concentrations at the
receptor distances are shown in Table 11-20 below. The change in annual mean
NO2 for each assessment location is low, and the predicted concentration with
construction traffic is less than 30µg/m3 for each location. The effect of increased
NO2 concentration as a result of construction traffic at the AQMA receptors is
therefore considered to be negligible.
Table 11-20: Maximum Annual Mean NO2 at AQMA Receptors
Receptor Distance from A’mouth Road
NO2 Concentrations (µg/m3)
Change in Annual Mean NO2 (µg/m
3)
Significance of Change Diffusion
Tube1
2012
Baseline2
2012
Do-Minimum 2019
With-Development construction traffic 2019
8m 34.7 34.4 28.0 28.6 +0.6 (<5% Increase)
Negligible
10m 34.0 34.1 27.7 28.3 +0.5 (<5% Increase)
Negligible
15m 31.8 33.3 27.1 27.6 +0.5 (<5% Increase)
Negligible
1 BCC 2012
2 With DMRB calculated traffic contribution
Operational Phase
Assessment of Point Source Emissions
11.5.28. The impact of point source emissions on human health receptors has been
determined from isopleth figures of pollutant dispersion and maximum model
output at discrete receptor locations. The maximum hourly, daily and annual
average predicted concentrations have been compared with the NAQS
objectives, as summarised in Tables 11-21 and 11-22 below.
11.5.29. These results represent the output from the worst-case modelled scenario
described in Table 11-4, which is Scenario C (i.e. 2 x 580MWe single-shaft
CCGTs and 240MWe of reciprocating diesel engines). Variation in the predicted
results with alternative Rochdale Envelope scenarios is presented in Appendix F,
Volume II of this PEI Report.
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-37
11.5.30. The following abbreviations are used in Tables 11-21 and 11-22:
• PC: This is the Process Contribution and represents the change caused
by the Proposed Development; and
• PEC: This is the Predicted Environmental Concentration and is PC plus
background concentration. It is the concentration expected at a particular
receptor once the effect of the Proposed Development is taken into
account.
Table 11-21: Maximum NO2 Predicted Concentrations at Human Health Receptors
Sensitive
Receptor
2019 NO2
Baseline1
(µg/m3)
Annual
Mean NO2
PC (µg/m3)
Magnitude of
Change
Annual
Mean PEC
(µg/m3)
Significance
of Effect
1 18.1 0.4 Low
(<5% Increase) 18.5 Negligible
2 18.1 0.3 Very Low
(<1% Increase) 18.4 Negligible
3 18.1 1.4 Low 19.5 Negligible
4 18.1 1.3 Low 19.4 Negligible
5 18.1 0.6 Low 18.7 Negligible
6 18.1 0.1 Very Low 18.2 Negligible
7 18.1 0.1 Very Low 18.2 Negligible
8 18.1 0.1 Very Low 18.2 Negligible
9 18.1 0.1 Very Low 18.2 Negligible
10 18.1 0.3 Very Low 18.4 Negligible
112
35.0 0.1 Very Low 35.1 Negligible
122
35.0 0.2 Very Low 35.2 Negligible
1. 2019 baseline used for opening year as a conservative assumption
2. R11 (Cribbs Causeway AQMA) and R12 (Avonmouth AQMA) baselines are taken from
most recent LA diffusion tube monitoring (2012) at these locations as worst-case
assumption.
Table 11-22: Maximum Predicted Concentrations at Worst Affected Human Health
Receptor
Pollutant Averaging
period
Process
Contribution
PC (µg/m3)
PC/ NAQS
Threshold for very
low change (%
NAQS)
Significance
of Effect
NO2 1-Hour mean
(99.8th %ile)
13.91
6.9% <10% Negligible
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May 2014 Page 11-38
Pollutant Averaging
period
Process
Contribution
PC (µg/m3)
PC/ NAQS
Threshold for very
low change (%
NAQS)
Significance
of Effect
PM10 24-Hour mean
(90.4th %ile)
1.02
2.0% <10% Negligible
PM10 Annual mean 0.23 0.5% <1% Negligible
1. PROW, 1km S of Proposed Development
2. PROW, 2km NE of Proposed Development
3. Easter Compton residences
11.5.31. The maximum process contribution of NO2 from any of the operational scenarios
results in a low change in the annual mean concentration at four of the identified
receptors. The ambient concentration at these receptors is well below the
objective with the Proposed Development, therefore the significance of the effect
at these receptors is predicted to be negligible. The magnitude of change at all
other human health receptors is very low and the significance of effect is also
negligible.
11.5.32. The magnitude of change in annual mean NO2 concentration at the identified
AQMAs (represented by receptors R11 and R12) from the Proposed
Development is very low, therefore the significance of effect at the AQMAs is
considered to be negligible.
11.5.33. The maximum short-term predicted concentration of NO2 at the worst affected
receptor (the PROW immediately south of Proposed Development) represents
6.6% of the daily mean NAQS objective and therefore is considered to be a very
low change. The Proposed Development short term contribution to hourly mean
NO2 is considered to have a negligible effect on human health receptors.
11.5.34. The maximum short-term and long term process contributions of PM10 at the
worst affected receptors represent very low changes in the mean concentration
over the appropriate averaging periods and therefore the Proposed Development
operational contribution of PM10 is considered to have negligible effect on
human health receptors.
11.5.35. The impact of point source emissions on sensitive ecological receptors has been
determined from isopleth figures of pollutant dispersion and maximum model
output at specified points. The maximum daily average and annual average
predicted concentrations have been compared with the CLPVEs, as summarised
in Table 11-23 below.
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May 2014 Page 11-39
Table 11-23: Maximum Predicted Concentrations of NOX at Statutory Ecological Receptors
Receptor Location
Annual mean predicted NOx
concentration
Maximum daily mean predicted NOx
concentration
PC
(µg/m3)
as % of
CLPVE Sig.
PC
(µg/m3)
as % of
CLPVE
Sig.
Severn Estuary (Atlantic salt marshes)
North 0.29 <1% Negligible 10.8 14%
Minor Adverse
West 0.17 <1% Negligible 6.0 <10% Negligible
Southwest 0.28 <1% Negligible 11.3 15% Negligible
Horseshoe Bend 0.13 <1% Negligible 3.7 <10% Negligible
Avon Gorge 0.12 <1% Negligible 2.7 <10% Negligible
Bushy Close 0.10 <1% Negligible 3.0 <10% Negligible
Gwent Levels – Magor and Undy
0.11 <1% Negligible 3.0 <10% Negligible
River Wye 0.15 <1% Negligible 2.0 <10% Negligible
Nedern Brook Wetlands, Caldicot
0.08 <1% Negligible 2.0 <10% Negligible
Weston Big Wood 0.14 <1% Negligible 2.1 <10% Negligible
Ashton Court 0.10 <1% Negligible 2.4 <10% Negligible
Weston-In-Gordano 0.13 <1% Negligible 1.9 <10% Negligible
11.5.36. The Proposed Development annual average contribution of NOX at all assessed
ecological receptors is predicted to be below the EA EPR threshold for
insignificance (<1%) for annual mean critical levels, representing changes of very
low magnitude at these receptors. The significance of effects of NOX emissions
on these receptors is therefore considered to be negligible.
11.5.37. The maximum contribution to the north of the Proposed Development occurs in
an area which is already exposed to baseline NOX above the CLPVE, at
30.7µg/m3, however as the contribution is <1%, and therefore considered very
low, the very low change represents a negligible effect on the Severn Estuary
SAC/SPA/Ramsar/SSSI at this location.
11.5.38. The maximum impact from the daily mean process contribution is predicted to the
southwest of the Proposed Development, resulting in a daily mean predicted
environmental concentration (PEC) of 11.3µg/m3, or 15% of the CLPVE. The
annual average background at this location is 15.8µg/m3, and it is usual to double
this when assessing short term (typically hourly) impacts, however as the CLPVE
is a daily average, this is not considered appropriate, as a daily average would be
likely to be below this value. Even when this approach is used, the CLPVE would
not be exceeded, with a predicted environmental concentration representing 57%
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-40
of the daily CLPVE. It is considered unlikely that the maximum process
contribution would result in exceedance of the daily mean at this location.
11.5.39. To the north of the Proposed Development the daily mean process contribution
represents 14.4% of the CLPVE. The annual average background concentration
at this location is much higher, at 30.7µg/m3, and therefore when this is doubled,
the PEC represents 96% of the CLPVE. As stated above, it is considered an over
estimate to use this approach for daily impacts, however even taking into account
this conservative assumption the effect is only predicted to be minor adverse,
due to the high background concentration.
11.5.40. The dispersion modelling includes a number of conservative assumptions in
combination, including:
• Use of the worst-case year of meteorological data;
• Maximum building sizes within the assessed Rochdale Envelope;
• Worst case CCGT configuration within the assessed Rochdale Envelope,
other configurations resulted in lower predicted impacts as shown in
Appendix F, Volume II of this PEI Report.
• Annual operation of 100% for both CCGT main plant units (8,760 hours
per year, compared with estimated 2,716 hours per year) and peaking
plant at maximum operation (1,500 hours per year);
• Operation of the plant at IED emission limits, when typical operational
concentrations for the Seabank 1 & 2 CCGTs are demonstrably
approximately half this value; and
• Conservative estimates of background concentrations at the sensitive
receptors.
11.5.41. For comparison, the dispersion model has also been run assuming the expected
actual annual operating hours of the CCGT units (2,716) and the resulting
process contributions at ecological receptors are presented in Table 11-24 below.
Table 11-24: Maximum Predicted Concentrations of NOX at Statutory Ecological Receptors –
Typical Operating Hours
Receptor Location
Annual mean predicted NOx
concentration
Maximum daily mean predicted
NOx concentration
PC
(µg/m3)
as % of
CLPVE Sig.
PC
(µg/m3)
as % of
CLPVE
Sig.
Severn Estuary
North 0.11 <1% Negligible 4.7 <10% Negligible
West 0.07 <1% Negligible 2.7 <10% Negligible
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May 2014 Page 11-41
Receptor Location
Annual mean predicted NOx
concentration
Maximum daily mean predicted
NOx concentration
PC
(µg/m3)
as % of
CLPVE Sig.
PC
(µg/m3)
as % of
CLPVE
Sig.
(Atlantic salt marshes)
Southwest 0.10 <1% Negligible 4.5 <10% Negligible
11.5.42. It can be seen that when the assessment is carried out at more realistic
operational levels that all the process contributions to the daily CLPVE are all
below the 10% threshold for insignificance for short term impacts.
11.5.43. As discussed above the coastal salt marshes are not listed as sensitive to NOX in
the atmosphere; taking into account the worst-case assumptions made in the
selection of dispersion model parameters the effect of additional operational
contributions on species present at this location may be considered negligible.
11.5.44. The impact of deposited nutrient nitrogen on the Severn Estuary
SAC/SPA/Ramsar/SSSI as a result of the maximum process contribution based
on 100% operation is shown in Table 11-25 below.
Table 11-25: Maximum Predicted Nutrient Nitrogen Deposition at Statutory
Ecological Receptors
Site Critical Load Range (kg N/Ha/year)
Predicted N deposition (kg N/Ha/year)
Predicted deposition as % of lower load
Significance
Severn Estuary (Atlantic salt marshes)
20-30 0.041 <1% Negligible
11.5.45. The most sensitive habitat within the Severn Estuary SAC/SPA/Ramsar/SSSI to
nutrient nitrogen deposition is listed as the Atlantic salt marshes, which are
present along Chittening Warth within 400m of the Proposed Development. The
maximum predicted nitrogen deposition resulting from operational emissions at
any location within the designated site is less than 1% of the lower critical load
defined for this habitat type and therefore the effect of operational emissions on
this habitat are considered to be negligible. No eutrophication impacts are
anticipated due to this negligible increase in nutrient deposition.
11.5.46. The Severn Estuary SAC/SPA/Ramsar/SSSI is designated for a number of
species that are potentially sensitivity to acidity, however no critical levels are
published for these species and therefore no quantitative assessment of acid
deposition as a result of operational emissions has been made.
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May 2014 Page 11-42
11.6. Residual Effects and Conclusions
Construction
11.6.1. The air quality assessment of construction impacts has assumed that the
measures outlined within the embedded mitigation section would be incorporated
into the design and construction management procedures of the Proposed
Development, as they are standard best practice measures that are routinely
applied across UK construction sites. No specific additional mitigation has been
identified as necessary for the construction phase of the Proposed Development.
For this reason, the residual effects would be as reported within the Potential
Effects section of this chapter. A summary of residual effects is provided in Table
11-29.
Operation
11.6.2. The air quality assessment of operational impacts has assumed that the IED
ELVs will be met for the operational plant in accordance with use of BAT under
the environmental permitting regime. No specific additional mitigation has been
identified as necessary for the operational phase of the Proposed Development.
For this reason, the residual effects would be as reported within the Potential
Effects section of this chapter. A summary of residual effects is provided in Table
11-26.
Decommissioning
11.6.3. Consistent with construction mitigation, it has been assumed that relevant best
practice dust mitigation measures would be in place during any decommissioning
works. No specific additional mitigation has been identified as necessary for the
decommissioning phase of the Proposed Development.
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May 2014 Page 11-43
Table 11-26: Summary of Significant Effects and Mitigation
Development Stage
Effect Without Mitigation
Significance of Effect Without Mitigation
Mitigation
Significance of Effect With Mitigation (Residual Effect)
Nature of Effect
Exhaust emissions associated with HDV movements during the enabling and construction programme
No significant impacts are anticipated prior to mitigation
Assessments include standard mitigation measures or BAT and therefore no unmitigated significance has been evaluated
The implementation of the mitigation measures outlined in the CEMP will minimise the release of pollutants
Negligible Temporary
Exhaust emissions from construction site plant
No significant impacts are anticipated prior to mitigation
Assessments include standard mitigation measures or BAT and therefore no unmitigated significance has been evaluated
The implementation of the mitigation measures outlined in the CEMP will minimise the release of pollutants
Negligible Temporary
Construction dust
Elevated emissions of particulates to air
Assessments include standard mitigation measures or BAT and therefore no unmitigated significance has been evaluated
The implementation of the mitigation measures outlined in the CEMP will minimise the release of pollutants
Negligible Temporary
Point source emissions associated with the operational development
Elevated emissions to air from stack emissions
Assessments include standard mitigation measures or BAT and therefore no unmitigated significance has been evaluated
The implementation of BAT and embedded mitigation by design will minimise emissions to air
Negligible Permanent
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May 2014 Page 11-44
11.7. Cumulative Effects Assessment
11.7.1. This section assesses the effect of the Proposed Development and associated
infrastructure in combination with other developments in the area, as outlined in
Chapter 7: Assessment Methodology.
11.7.2. There are no cumulative traffic and point source effects from the Proposed
Development as traffic impacts will occur during construction, while point source
impacts will occur during plant operation.
11.7.3. A number of cumulative schemes are identified in Chapter 7: Assessment
Methodology, of which preliminary modelling has demonstrated only two have the
potential to create cumulative effects on air quality with the Proposed
Development, as discussed below.
11.7.4. The Severnside Energy Recovery Centre and Avon Power Station consented
schemes are sufficiently close to the Proposed Development and of sufficient
scale to have the potential to contribute to cumulative impact on identified
receptors; these have been modelled together with predicted emissions from the
Proposed Development to determine the overall potential impact. Where data is
unavailable for the cumulative consented scheme, representative estimates have
been made. A summary of the modelled data used in this assessment is provided
in Table 11-27. It should be noted that the Seabank 1 & 2 generating station is
already operational and its effects are therefore assumed as being captured
within the baseline data used in the assessment.
11.7.5. The typical operational scenario (2,716 hours/year) has been assumed for the
Proposed Development for assessment of realistic worst-case long term effects.
Table 11-27: Modelled Input Parameters – Cumulative Effects Assessment
Parameter
SITA (32MW) –
Single Stack
Avon Power
(1200MW) – Each of
2 stacks
Stack Height (m) 126 100
Efflux Velocity (m/s) 15 44
Emission Temperature (°C) 150 80
Volumetric Flow (Nm3/hr)
250,000 3,408,000
Volumetric Flow at stack exit
parameters (Am3/hr)
110 865
Flue Diameter (m) 3.0 5
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May 2014 Page 11-45
Parameter
SITA (32MW) –
Single Stack
Avon Power
(1200MW) – Each of
2 stacks
Assumed maximum operating hours /
year 8,760 8,760
NOx ELV (IED, mg/Nm3) 200 30
Assumed stack location 353750, 182750 354200,182800
354250,182790
11.7.6. The predicted concentrations from cumulative source modelling indicate that the
additional contributions from the Proposed Development are unlikely to result in
exceedance of hourly or annual mean NAQS objectives at the worst-affected
human health receptors (Marsh Common, Severn Beach residences).
11.7.7. The predicted concentrations from cumulative source modelling indicate that the
additional contributions from the Proposed Development would result in a low
change in annual mean NO2 at the worst-affected area of the Severn Estuary
SAC/SPA/Ramsar/SSSI (north of the Proposed Development Site) where the
baseline is already anticipated to be in exceedance of the CLPVE. The
cumulative impact of the combined emissions would therefore lead to a minor
adverse impact in this location.
Table 11-28: Cumulative Assessment: Maximum Predicted Concentrations
Pollutant Averaging
period
NAQS2
(µg/m3)
Cumulative
Contribution
(CC, µg/m3)
CC/
NAQS2
AC
(µg/m3)
PEC/NAQS2
NO2
1-Hour
mean
(99.8th %ile)
200 10.5 5.3% 36.2 23%
NO2 Annual
mean 40 1.5 4.9% 18.1 49%
NOx as
NO2 Daily mean 75 9.4
1 12.5% 70.8
1 94%
NOx as
NO2
Annual
mean 30 0.3
1 1.1% 30.7
1 103%
1. Assuming northern receptor location
2. NAQS or CLPVE as relevant
11.7.8. The above cumulative assessment takes into account a number of conservative
assumptions as outlined in Section 11.5.40.
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11.7.9. It is considered that the above assumptions lead to a worst-case assessment of
potential cumulative effects at human health and ecological receptors as a result
of the combined consented schemes with additional worst-case contributions
from the Proposed Development. As such the cumulative impacts are expected
to result in a minor adverse effect at the Severn Estuary
SAC/SPA/Ramsar/SSSI as a worst-case.
11.8. Impacts and Effects yet to be Determined
11.8.1. There are no impacts and effects yet to be determined, however, the scheme
design may be subject to refinement prior to submission of the final DCO
application. Any changes that lead to differing or new impacts and effects will be
highlighted within the final ES, along with the reasons for the change.
11.8.2. It is also possible that the baseline conditions will change between the
preparation of this PEI Report and the final ES; air quality conditions are dynamic
and evolve over time. The Proposed Development Site is currently subject to
excavation, top soil stripping, and levelling in certain areas in order for third
parties to deliver the Spine Access Road and new channel for the Red Rhine,
which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7:
Assessment Methodology. A haul road is also being constructed through the
middle of the Proposed Development Site to enable access by third party from
the roundabout to the east of the Site to the Severnside Energy Recovery Centre
to the west. These works onsite are being undertaken by other developers, under
extant planning permissions and are separate to the Proposed Development.
11.8.3. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changes
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
11.8.4. The significance of effects of point source emissions on ecological receptors,
through deposition of nutrient nitrogen or acidity, has been evaluated using the
EA insignificance criterion of 1% of the long term critical level objective, as
above. At this stage no evaluation of contribution to critical loads has been
undertaken; the need for this will be considered following the Stage 2
consultation, and if required, included in the final ES.
11.8.5. Monitoring data from the automatic and non-automatic sites in the area were
presented in Table 11-12 for 2012 (the most recent year’s ratified data available
at the time of writing). This secondary baseline data will be updated for the final
ES, although it is not intended that further diffusion tube monitoring will be
undertaken.
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11.9. References
Ref. 11-1 Environmental Protection. The Air Quality Standards Regulations
2010 No.1001; The National Archives; 2010
Ref. 11-2 European Directive on Ambient Air Quality 2008/50/EC
Ref. 11-3 European Fourth Daughter Directive on Ambient Air Quality
2004/107/EC
Ref. 11-4 UK Environment Act 1995; reviewed 2007
Ref. 11-5 European Directive on Industrial Emissions 2010/75/EU
Ref. 11-6 Integrated Pollution Prevention and Control Reference Document on
the Best Available Techniques for Large Combustion Plant; European
Commission 2006
Ref. 11-7 UK Environmental Permitting (England and Wales) Regulations 2010
(EPR) (as amended)
Ref. 11-8 Environmental Permitting Regulation Horizontal Guidance,
Environmental Risk Assessment, Annex F – Air Quality; Environment
Agency; 2011
Ref. 11-9 Design Manual for Roads and Bridge (DMRB), Volume 11
Environmental Assessment, Section 3 Environmental Assessment
Techniques, Part 1, HA207/07 Air Quality; Highways Agency; 2007
Ref. 11-10 NPPF Technical Guidance; Department for Communities and Local
Government, 2012
Ref. 11-11 Guidance on the Assessment of the Impacts of Construction on Air
Quality and the Determination of their Significance; Institute of Air
Quality Management; 2011
Ref. 11-12 Control of Dust from Construction and Demolition Activities; Building
Research Establishment; 2003
Ref. 11-13 Development Control: Planning for Air Quality (2010 Update); Update
guidance from Environmental Protection UK on dealing with air
quality concerns within the development control process; EPUK; 2010
Ref. 11-14 LAQM TG(09)
Ref. 11-15 http://laqm.defra.gov.uk/review-and-assessment/tools/background-
maps.html; DEFRA; Accessed February 2014
Ref. 11-16 AQTAG06 Environment Agency; 2011
Seabank 3 PEI Report – Chapter 11 Air Quality
May 2014 Page 11-48
Ref. 11-17 Site Relevant Critical Loads and Source Attribution; Centre for
Ecology and Hydrology; Available from: http://www.ceh.ac.uk
Accessed February 2014.
Ref. 11-18 Atmospheric Dispersion Modelling System (ADMS) User Guide;
Cambridge Environmental Research Consultants Ltd; 2012
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12. Noise and Vibration
12.1. Introduction
12.1.1. This chapter provides an assessment of noise and vibration effects that may
occur during the construction, operational and decommissioning phases of the
Proposed Development.
12.1.2. The aims of this chapter are to:
• Determine the existing noise climate at the nearest sensitive receptors to
the Proposed Development;
• Assess the likely noise and vibration effects from the enabling works and
construction activities, operation, and decommissioning of the Proposed
Development;
• Assess the offsite noise effects associated with any increases in road
traffic flows as a result of the Proposed Development; and
• Recommend noise mitigation measures, if required.
12.1.3. Details of noise terminology and theory relevant to this report are presented in
Appendix G Part 1, Volume II of this PEI Report.
Consultation
12.1.4. A scoping request was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on the proposed structure,
methodology and content of this chapter. A summary of stakeholder comments
and how they have been incorporated into this PEI Report chapter are provided
in Table 12-1.
Table 12-1: Scoping Opinion Responses Relevant to Noise and Vibration
Stakeholder Comment Addressed within the Report
Planning Inspectorate
Information should be provided on the types of vehicles and plant to be used during the construction phase, whilst noise generated during operation should also be identified and assessed.
See section 12.5 of this chapter and Appendix G Part 3, Volume II of this PEI Report.
Construction noise and vibration impacts on people should be assessed, including any potential for disturbance at night, at weekends and other unsocial hours.
See section 12.5 of this chapter.
Noise and vibration impact along the foreshore and within watercourses in/near the site should be addressed.
See section 12.5 of this chapter.
The study area should extend to potential noise impacts off site.
See section 12.5 of this chapter.
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Stakeholder Comment Addressed within the Report
Consideration should be given to monitoring noise complaints during construction and when the development is operational.
See section 12.5 of this chapter
NE
NE suggests that the influence of terrain and prevailing winds need to be incorporated into the methodology when mapping sound 'contours'.
See section 12.2 of this chapter.
With the development potentially being phased over 3 years, it is important to consider the seasonal impacts of the development and avoid noisy or disruptive activities in sensitive areas, for example laying pipes in winter months across known wintering bird habitat.
See section 12.5 of this chapter for predicted noise levels and Chapter 16: Ecology for an assessment of the effect on habitats and species.
SGC
It is recommended that baseline noise monitoring should be undertaken further North of Elmtree Farm. This would be around the Marsh Common area and would include properties such as Gilslake.
See section 12.3 of this chapter.
With regards to the operating noise level our aim would be to achieve a 0 decibel (dB) increase above existing background rather than +5dB. If this cannot be achieved then we would seek reasons as why this is the case and therefore consider if a +5dB would be acceptable in this case based on the number of nearby residential properties.
See sections 12.1 and 12.5 of this chapter.
BCC Agreed to the same operating noise level criterion as SGC. No further comments were received.
-
12.1.5. Further consultation took place with the Environmental Health Officers at SGC
and BCC in May 2013 (documented by email) regarding the measurement and
assessment methodologies following receipt of the Scoping Opinion. The
following were agreed:
• Long-term and short-term noise monitoring locations, as described later
in this chapter;
• Monitoring protocol (noise levels to be logged in contiguous 15 minute
intervals at long-term locations, and one hour intervals during the day
and five minute intervals during the night at short-term locations);
• Construction noise effects to be assessed using the ABC method in
BS 5228: 2009+A1: 2014 ‘Code of Practice for Noise and Vibration
Control on Construction and Open Sites’ (Ref. 12-1); and
• Operational noise impacts to be assessed using BS 4142: 1997 'Method
for rating noise affecting mixed residential and industrial areas' (Ref. 12-
2). The Rating Level should aim to be 0dB above the background noise
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level, although a Rating Level of 5dB above the background level may be
satisfactory depending on the number of sensitive receptors affected.
Legislation and Planning Policy
12.1.6. Appendix D, Volume II of this PEI Report presents a summary of the planning
policy relevant to this chapter.
12.1.7. Other guidance that is applicable to this assessment is outlined below.
• British Standard (BS) 5228: 2009+A1: 2014 ‘Code of Practice for Noise
and Vibration Control on Construction and Open Sites’. Noise and
vibration levels generated by construction activities are regulated by
guidelines and are subject to local authority control. No UK national noise
limits exist for construction noise. However, guidance on acceptable
noise levels is provided by this BS.
• World Health Organisation (WHO) Guidelines (Ref. 12-3). With regard to
daytime levels in outdoor areas, e.g. rear gardens, over the 16-hour
daytime period (7.00am – 11.00pm) the WHO Guidelines state “few
people are highly annoyed at LAeq levels below 55dB(A)”. This guideline
is commonly used as an upper level for gardens. The WHO Guidelines
also provide criteria for individual noise events at night. It advises that
LAmax,fast levels inside bedrooms should not regularly exceed 45dB, and if
occupants are to use open windows for ventilation, external levels should
not regularly exceed 60dB LAmax,fast (this assumes a 15dB reduction
through a partially open window).
12.2. Assessment Methodology and Significance Criteria
Construction Noise
Assessment Methodology
12.2.1. Construction noise and vibration levels have been predicted using the
methodology given in BS 5228: 2009+A1: 2014 ‘Code of Practice for Noise and
Vibration Control on Construction and Open Sites’. This includes enabling works,
which will pre-empt the main construction activities and are assumed to be less
noisy than the later phases of work onsite.
12.2.2. Noise levels experienced by local receptors during construction depend upon a
number of variables, the most significant of which are:
• The noise generated by plant or equipment used on site, road traffic and
other sources, generally expressed as sound power levels (Lw);
• The periods of use of the plant on site, known as its on-time;
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• The distance between the noise source and the receptor;
• The attenuation due to ground absorption, air absorption and barrier
effects; and
• In some instances, the reflection of noise due to the presence of hard
surfaces such as the sides of buildings.
12.2.3. Specific details of construction works will not be available until after receipt of the
DCO and during detailed design of the Proposed Development. Therefore,
representative construction activities and worst case assumptions have been
assumed based on experience of similar projects.
12.2.4. Sound power levels for each piece of equipment for each construction activity
have been sourced from BS 5228 ‘Control of noise on construction and open
sites’ (Part 1), which provides measured noise levels for various items of
construction plant. The source data input into the calculation spread sheets are
provided in Appendix G Part 3, Volume II of this PEI Report.
12.2.5. The following major activities have been assumed during the enabling works and
construction of the Proposed Development:
• Site clearance;
• Earthworks;
• Piling (bored);
• Excavation and foundations;
• Slab construction;
• Steelwork construction;
• Services and fitting; and
• Access/on-site road and car parking construction.
12.2.6. It is anticipated that the construction works within the Other DCO Land, which
includes the laying of the cooling water pipeline and installation of the electrical
cable, will comprise:
• Site clearance;
• Earthworks;
• Excavation and foundations;
• Laying of the pipeline / construction of the cable rack; and
• Backfill.
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Significance Criteria
12.2.7. BS 5228 contains a methodology for the assessment of the significance of effect
of construction noise in relation to the ambient noise levels at nearby residential
dwellings, known as the ABC method. The thresholds provided in BS 5228-1:
2009+A1: 2014 are reproduced below in Table 12-2.
Table 12-2: Construction Noise Thresholds at nearby Residential Dwellings
Assessment Category Threshold Value (dB) (LAeq,T)
Category A A)
Category B B)
Category C C)
Night-time (11.00pm – 7.00 am) 45 50 55
Evenings and weekends D)
55 60 65
Daytime (7.00am – 7.00pm) and Saturdays (7.00am – 1.00pm)
65 70 75
NOTE 1: A potential significant effect is indicated if the total LAeq noise level arising from the site exceeds the threshold value for the category appropriate to the ambient noise level.
NOTE 2: If the ambient noise level exceeds the Category C threshold values given in the table (i.e. the ambient noise levels is higher than the above values), then a potential significant effect is indicated if the total LAeq,T noise level for the period increases by more than 3dB due to site noise.
NOTE 3: Applies to residential receptors only. A)
Category A: Threshold values to use when ambient noise levels (when rounded to the nearest 5dB) are less than these values. B)
Category B: Threshold values to use when ambient noise levels (when rounded to the nearest 5dB) are the same as Category A values. C)
Category C: Threshold values to use when ambient noise levels (when rounded to the nearest 5dB) are higher than Category A values. D)
7.00pm –11:00pm weekdays, 1:00pm – 11:00pm Saturdays, 7:00am – 11pm Sundays.
12.2.8. For the appropriate period (night, evening/weekend, day), the ambient noise level
is rounded to the nearest 5dB. The appropriate assessment category is
established and the total predicted construction noise level is then compared with
this Threshold Value. If the predicted total noise level exceeds the Threshold
Value, then a significant effect is deemed to occur.
12.2.9. The criteria shown in Table 12-3 have been used to assess the significance of
construction noise levels, modified to be consistent with the methodology used in
this PEI Report which categorises significance in terms of Negligible, Minor,
Moderate or Major effects (beneficial or adverse). For the purpose of this
assessment moderate and major effects are assumed to be ‘significant’.
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Table 12-3: Significance Criteria for Construction Noise
Construction Noise Level above Threshold Value at the façade (dB)
Magnitude of Change Significance of Effect
<1 None to Slight Negligible (adverse)
1>3 Minor Minor adverse
3>5 Moderate Moderate adverse
5+ Major Major adverse
Construction Vibration
Assessment Methodology
12.2.10. The limit of human perception to vibration is of the order of 0.15 millimetres per
second (mm/s) to 0.3mm/s peak particle velocity (ppv), in the frequency range
0.1 hertz (Hz) to 1500Hz.
12.2.11. The human body is not equally sensitive to all frequencies of vibration and
therefore weighting curves to reflect the frequency dependency of the body have
been developed and are provided within international (ISO) Standards. The
weighting gives a good correlation between the measured vibration level and the
subjective feeling or impact produced by the vibration.
12.2.12. Ground vibrations may cause reactions ranging from ‘just perceptible’ through
‘concern’ to ‘alarm’ and ‘discomfort’. The subjective response varies widely and is
a function of situation, information, time of day and duration.
12.2.13. BS 5228: Part 2 provides historic measured vibration levels for various piling
methods. For example indicative vibration levels for impact bored piling are a ppv
of 7.1mms-1 when measured at 3m, a ppv of 2.3mms-1 at 5.5m and a ppv of
0.9mms-1 at 10m. This clearly demonstrates how quickly vibrations reduce with
distance. Vibration from other methods of piling, such as bored piling or
continuous flight auger (CFA) piling will produce much lower levels of vibration.
Significance Criteria
12.2.14. The predicted ppv levels are compared to the guidance levels in Table B.1 in
BS 5228, 2009 (reproduced as Table 12-4), to identify the likelihood of complaint.
The category for ‘neutral’ and ‘negligible’ effects has been merged to be
consistent with the methodology adopted for this PEI Report.
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Table 12-4: Guidance Effects of Vibration for Human Response (from BS 5228: Part 2: 2009)
Vibration Level mm/s
Impact Significance of Effect
0.14 - 0.3 Vibration might be just perceptible in the most sensitive situations for most vibration frequencies associated with construction at 0.14mm/s. At lower frequencies, people are less sensitive to vibration
Vibration might be just perceptible in residential environments at 0.3mm/s
Negligible (adverse)
0.3-1.0 It is likely that vibration of this level in residential environments will cause complaint, but can be tolerated if prior warning and explanation has been given to residents.
Minor adverse
1.0-10 Vibration is likely to cause complaints regardless of prior warning and explanation.
Moderate adverse
10.0 Vibration is likely to be intolerable for any more than a brief exposure to this level.
Major adverse
Operational Noise
Assessment Methodology
12.2.15. A noise propagation model has been developed in the SoundPLAN suite of
programs to assess the Proposed Development. SoundPLAN implements ISO
9613-2: 1996 ‘Attenuation of sound during propagation outdoors’ (Ref. 12-4).
12.2.16. The model consists of a detailed three dimensional representation of the
Proposed Development and its surroundings. It assumes that the prevailing wind
direction is always from source to receiver, which is likely to overestimate the
noise effect associated with the Proposed Development. It has been employed to
calculate noise levels at surrounding sensitive receptors due to noise breakout
from the proposed buildings and noise emission from external sources.
12.2.17. All significant topographical detail and buildings that may influence the
transmission of noise to affected receptors are included in the noise model. A
digital terrain model, created using ground elevation contours has been used to
position buildings and other noise sources at the correct height. Local structures
offsite that have been included in the model include Seabank 1 & 2 and the
Avonmouth LNG Storage Facility.
12.2.18. BS 4142: 1997 'Method for rating noise affecting mixed residential and industrial
areas' details a method of rating the acceptability of the noise from fixed plant
(electricity substations, pumps, generators, etc.) in existing or proposed
developments such as power stations, factories and commercial/industrial units.
12.2.19. The basis of the standard is a comparison between the background noise level in
the vicinity of residential locations and the specific noise level (adjusted for
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characteristic features) of the noise source under consideration. The relevant
parameters in this instance are as follows:
• Background Noise Level - LA90,T - defined in the Standard as ‘the ‘A’
weighted sound pressure level at the assessment position without the
industrial source operating, which is exceeded for 90% of the given time
interval, T, measured using time weighting F (fast);
• Specific Noise Level - LAeq,Tr - the equivalent continuous ‘A’ weighted
sound pressure level of the source in question over a given time interval;
and
• Rating Level - LAr,Tr - the specific noise level plus any adjustment made
for the characteristic features of the noise.
12.2.20. A correction of +5dB is made to the specific noise level if one or more of the
features noted below is present. Only one +5dB correction is made regardless of
the specific noise level containing one or more of the following characteristics.
• The noise contains a distinguishable, discrete, continuous note (whine,
hiss, screech, hum, etc.);
• The noise contains distinct impulses (bangs, clatters or thumps); or
• The noise is irregular enough to attract attention.
12.2.21. The following assumptions have been made when undertaking the operational
noise predictions to ensure a robust assessment:
• The Proposed Development will operate at full load, 24 hours a day and
will comprise 240MW of peaking plant and 1,160MW of CCGT (a total of
1,400MW);
• The cooling method employed for the Proposed Development is hybrid
cooling water system;
• The cladding to be applied to all buildings will be single skin;
• A 5dB correction has been applied to account for any noise
characteristics, such as a hum or whine, as explained above; and
• The facility will be designed to meet the noise levels given for
plant/breakout noise used in this assessment.
12.2.22. The predictions have been carried out for both the single-shaft and multi-shaft
configurations, which make slightly different noise contributions to selected
receptors due to the different position of equipment onsite.
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12.2.23. The settings used in the noise modelling software and the list of assumptions
used are presented in Appendix G Part 4, Volume II of this PEI Report.
Significance Criteria
12.2.24. Once any adjustments have been made, the background and the Rating Levels
are compared. The standard suggests that the greater this difference is, the
greater the likelihood of complaints, as follows:
• A difference of around +10dB or more indicates that complaints are
likely;
• A difference of around +5dB is of marginal significance; and
• If the Rating Level is more than 10dB below the measured background
level, this is a positive indication that complaints are unlikely.
12.2.25. The standard specifies a one hour assessment period during the day and a five
minute period at night.
12.2.26. The significance criteria that have been produced for assessing operational noise
are provided in Table 12-5. Moderate and major effects are considered to be
‘significant’.
Table 12-5: Significance Criteria for Operational Noise
Rating Level above Background Level (dB)
BS 4142 Assessment Significance of Effect
≤ -10 Complaints unlikely Negligible (adverse)
-9 to 0 Less than marginal significance
1 to +5 Marginal significance Minor adverse
+6 to +9 Greater than marginal significance
Moderate adverse
≥ +10 Complaints Likely Major adverse
Road Traffic Noise
Assessment Methodology
12.2.27. The Proposed Development will lead to an increase in traffic flows on the local
road network, both during construction and once the Proposed Development is
operational. The assessment focuses on the effect at existing residential
properties located along surrounding affected roads.
12.2.28. The magnitude of the effect of the additional traffic generated by the construction
and operation of the Proposed Development has been assessed by calculating
the potential change in the 18-hour traffic noise levels (LA10,18h) at a selection
of sensitive receptors along affected roads.
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12.2.29. The Design Manual for Roads and Bridges (DMRB) (Ref. 12-5), published by the
Highways Agency, requires that an assessment is carried out where changes in
traffic result in noise changes greater than 1dB(A). Assuming that other
parameters (e.g. speed and proportion of HGVs) do not change, this is equivalent
to a change in the road traffic flow of +25% or -20%. This implies that road traffic
flow changes of up to 25% offer no significant effect in environmental noise terms
(assuming that speed and the proportion of HGVs do not change).
12.2.30. The calculations have employed the methodology provided in Calculation of
Road Traffic Noise (CRTN) (Ref. 12-6), which is the standard methodology
adopted in the UK for the calculation of noise levels from road traffic.
Significance Criteria
12.2.31. The significance criteria employed in this assessment of the significance of
changes in road traffic noise levels during the operation of the development are
provided in Table 12-6. This is taken from Table 3.1 of the DMRB.
Table 12-6: Scheme for Assessment of Changes in Road Traffic Noise Levels
Change in Noise Level (dB) Magnitude of Change Significance of Effect
0 – 0.9 Negligible Negligible (adverse)
1.0 – 2.9 Minor Minor adverse
3.0 – 4.9 Moderate Moderate adverse
5.0+ Major Major adverse
Receptor Locations
12.2.32. Free-field construction and operational noise levels for a typical one hour period
have been predicted at the location of the closest receptors to the proposed
works. These receptors have been chosen as they are representative of the
closest noise sensitive properties in different directions from the Proposed
Development Site. The selected receptors, and their distance from the closest
proposed buildings (i.e. CCGT’s or peaking plants) are:
• R1: Barnacre, Hallen, approximately 1.1km to the southeast of the
Proposed Development Site;
• R2: Elmington Manor Farm, approximately 1.1km to the southeast of the
Proposed Development Site;
• R3: Orchard Cottage, Easter Compton, approximately 1.5km to the east
of the Proposed Development Site;
• R4: 104 Marsh Common Road, Pilning, approximately 2.2km to the
northeast of the Proposed Development Site;
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• R5: 2 Severnwood Gardens, Severn Beach, approximately 1.5km to the
north of the Proposed Development Site.; and
• R6: Chittening Warth mudflats, which are part of the Severn Estuary
SAC/SPA/Ramsar/SSSI site, located approximately 400m to the
northwest of the Proposed Development Site.
12.2.33. The locations of these receptors are illustrated in Figure 12-1, Volume III of this
PEI Report.
Key Parameters for Assessment
12.2.34. The assessment employs the ‘Rochdale Envelope’ approach (as detailed in the
Planning Inspectorate Advice Note 9). Given the locations of the CCGT plant, the
hybrid cooling water system and the peaking plant, which together constitute the
main noise sources, are relatively fixed in the DCO Application, any movement of
plant items within these areas is unlikely to result in significant changes to the
resultant noise levels at the surrounding receptors. Hence, having based the
modelling on the indicative site layout presented on Figures 4-2 and 4-3 in
Volume III of this PEI Report is considered to be robust.
12.2.35. To take account of the required flexibility in building heights, the maximum
proposed building heights are employed in the modelling and assessment work.
This will provide a worst case in terms of building breakout noise.
12.2.36. The assessment has also assumed the worst case mix of plant, which constitutes
both the CCGT plant and peaking plant.
12.2.37. The operational noise predictions have been carried out for the CCGT plant for
both the single-shaft and multi-shaft configurations, due to the different position
of equipment and therefore potential to cause slightly different noise contributions
to selected receptors.
12.3. Baseline Conditions
Measured Noise Levels
12.3.1. A baseline noise survey was conducted between September and October 2013
in accordance with the methodology agreed with SGC and BCC in May 2013.
12.3.2. Long-term monitoring was undertaken at two locations, representative of the
nearest accessible residential receptors in each direction from the Proposed
Development Site. These were:
• LT1: Barnacre, Severn Road, Hallen; and
• LT2: Orchard Cottage, Vimpennys Lane, Easter Compton.
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12.3.3. Short-term, attended noise monitoring during the day and night was undertaken
at three locations. These were:
• ST1: Marsh Common Road, Pilning;
• ST2: Severnwood Gardens, Severn Beach; and
• ST3: Severn Road, close to the existing Seabank 1 & 2 Power Station.
12.3.4. These noise monitoring locations are illustrated in Figure 12-1 (Volume III of this
PEI Report).
12.3.5. All measurements conformed to the requirements of BS 7445: 2003 (Ref. 12-7)
with regards to the positioning of the meters. During the long-term
measurements, weather conditions were generally within the weather condition
requirements. Noise data collected when weather conditions were outside the
requirements have been omitted.
12.3.6. Noise measurement data during periods when weather conditions satisfied the
requirements of BS 7445 are presented in Table 12-7.
Table 12-7: Free-field Ambient Noise Levels during Good Weather Conditions
Location Measurement address
Day Night
LAeq,T
dB*
Ave LA90,T
dB†
LAmax,fast
dB
LAeq,T
dB*
Ave LA90,T
dB†
LAmax,fast
dB
LT1 Barnacre, Hallen 49 45 80 43 38 85
LT2 Orchard Cottage, Easter Compton
50 45 84 45 38 71
ST1 Marsh Common Road, Pilning
57 53 74 45@
38@
71@
ST2 Severnwood Gardens, Severn Beach
64 54 87 60 47 76
ST3 Severn Road 71 64 90 66 41 83
* This is the lowest of the average daytime or night-time LAeq.
† This is the lowest of the average daytime or night-time LA90. @
Noise levels measured at this location at night were professionally judged to be incorrect (much higher
than expected) for a location of this type. Therefore, for a worst-case assessment noise levels at this
location have been assumed to be the same as those at Orchard Cottage, judged to have a quieter
prevailing noise climate than that at ST1.
12.3.7. Further information on the measured data is provided in Appendix G Part 2,
Volume II of this PEI Report. Table 12-8 provides a summary of the observations
during the monitoring.
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Table 12-8: Observations during the Baseline Monitoring
Location Measurement address
Description of main noise sources
LT1 Barnacre, Hallen Road traffic on the M49, M5 and Severn Road, rusting leaves, and birdsong
LT2 Orchard Cottage, Easter Compton
Road traffic on the M49, birdsong, and rustling leaves
ST1 Marsh Common Road, Pilning
Road traffic on the M49 and Marsh Common Land, rustling leaves, and occasional overhead aircraft
ST2 Severnwood Gardens, Severn Beach
Road traffic on the A403 Severn Road
ST3 Severn Road Road traffic on Severn Road
Threshold Values
12.3.8. Based on the measured ambient noise levels, the following ABC Threshold
Values (from in BS 5228: 2009) have been derived and are used in this
assessment.
Table 12-9: Threshold Values at Selected Receptors
Location
LAeq,T dB Day LAeq,T dB Night
Daytime LAeq,T dB
Daytime Threshold
Value
Night-time LAeq,T dB
Night-time Threshold
Value
R1: Barnacre 49 65 43 50
R2: Elmington Manor Farm 49 65 43 50
R3: Orchard Cottage 50 65 45 50
R4: 104 Marsh Common Road 57 65 45 50
R5: 2 Severnwood Gardens 64 70 60 55
R6: Chittening Warth (90m from Severn Road)*
52 Not applicable to habitat sites
47 Not applicable to habitat sites
* This level has been calculated using a distance correction equation and based on the measured noise level 10m
from Severn Road.
12.4. Development Design and Impact Avoidance
12.4.1. The design of the Proposed Development has been carried out in conjunction
with the acoustics consultants to identify locations and building orientations that
would minimise the noise impact at nearby noise sensitive receptors.
12.4.2. Noise mitigation measures that were analysed during the preparation of the
concept layout included building cladding providing a minimum attenuation of
25dB Rw.
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12.5. Potential Effects and Mitigation Measures
Construction Phase
Enabling Works and Site Construction
12.5.1. The estimated free-field construction noise levels at the identified receptors for
each activity during the enabling works and construction of the main Proposed
Development, including vehicle movements on site, are provided in Table 12-10.
Table 12-10: Predicted Free-Field Construction Noise Levels
Construction Activity
Predicted Total Construction Noise Level LAeq,1h dB
R1: Barnacre
R2: Elmington
Manor Farm
R3: Orchard Cottage
R4: 104 Marsh
Common Road
R5: 2 Severnwood
Gardens
R6: Chittening
Warth
Site clearance 42 42 41 38 42 63
Site earthworks 34 34 33 30 35 56
Bored piling (CFA) 37 37 36 34 38 46
Excavations and foundations
38 38 37 34 38 46
Slab construction 35 35 34 32 36 44
Steelwork construction
38 38 37 34 39 46
Finishing and fitting 34 34 33 31 35 43
Hardstanding 37 37 37 34 38 46
Access roads/car-parking
38 38 37 34 39 60
12.5.2. The significance of effect for each construction activity and at each residential
receptor is provided in Table 12-11. Receptor 6 (Chittening Warth) is discussed
after Table 12-11.
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Table 12-11: Difference between Predicted Construction Noise Level and Threshold Value
Activity R1: Barnacre R2: Elmington Manor
Farm
R3: Orchard Cottage R4: 104 Marsh
Common Road
R5: 2 Severnwood
Gardens
Change
(dB)
Significance Change
(dB)
Significance Change
(dB)
Significance Change
(dB)
Significance Change
(dB)
Significance
DAYTIME
Site clearance -23 Negligible -23 Negligible -27 Negligible -24 Negligible -28 Negligible
Site earthworks
-32 Negligible -32 Negligible -35 Negligible -32 Negligible -35 Negligible
Bored piling (CFA)
-28 Negligible -28 Negligible -31 Negligible -29 Negligible -32 Negligible
Excavations and foundations
-27 Negligible -27 Negligible -31 Negligible -28 Negligible -32 Negligible
Slab construction
-30 Negligible -30 Negligible -33 Negligible -31 Negligible -34 Negligible
Steelwork construction
-27 Negligible -27 Negligible -31 Negligible -28 Negligible -31 Negligible
Finishing and fitting
-31 Negligible -31 Negligible -34 Negligible -32 Negligible -35 Negligible
Hardstanding -28 Negligible -28 Negligible -31 Negligible -28 Negligible -32 Negligible
Access roads/car-parking
-27 Negligible -27 Negligible -31 Negligible -28 Negligible -31 Negligible
NIGHT-TIME
Site clearance -8 Negligible -9 Negligible -9 Negligible -12 Negligible -13 Negligible
Site earthworks
-16 Negligible -16 Negligible -17 Negligible -20 Negligible -20 Negligible
Bored piling (CFA)
-13 Negligible -13 Negligible -14 Negligible -16 Negligible -17 Negligible
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May 2014 Page 12-16
Activity R1: Barnacre R2: Elmington Manor
Farm
R3: Orchard Cottage R4: 104 Marsh
Common Road
R5: 2 Severnwood
Gardens
Change
(dB)
Significance Change
(dB)
Significance Change
(dB)
Significance Change
(dB)
Significance Change
(dB)
Significance
Excavations and
foundations
-12 Negligible -12 Negligible -13 Negligible -16 Negligible -17 Negligible
Slab construction
-15 Negligible -15 Negligible -16 Negligible -18 Negligible -19 Negligible
Steelwork construction
-12 Negligible -12 Negligible -13 Negligible -16 Negligible -16 Negligible
Finishing and fitting
-16 Negligible -16 Negligible -17 Negligible -19 Negligible -20 Negligible
Hardstanding -13 Negligible -13 Negligible -13 Negligible -16 Negligible -17 Negligible
Access roads/car-
parking
-12 Negligible -12 Negligible -13 Negligible -16 Negligible -16 Negligible
Seabank 3 PEI Report – Chapter 12 Noise and Vibration
May 2014 Page 12-17
12.5.3. The predicted noise levels from enabling works and construction activities fall
well below the daytime and night-time ABC threshold values for each selected
receptor R1-5. The predicted significance of this effect is therefore considered to
be negligible.
12.5.4. With the exception of site clearance and access road construction works during
both the daytime and night-time, the predicted noise levels from enabling works
and construction activities also fall below the measured LAeq levels at the nearest
habitat receptor, which is Chittening Warth within the Severn Estuary
SAC/SPA/Ramsar /SSSI sites (Receptor 6). The significance of this predicted
effect is therefore assessed as negligible.
12.5.5. During site clearance works the noise levels at R6 are predicted to be 63dB and
during access road construction noise levels are predicted to be 60dB, which
may result in a major adverse noise effect without additional mitigation; however,
the predicted noise levels are based on worst-case assumptions and do not
include control measures to reduce noise effects, which are discussed below.
12.5.6. Following the implementation of mitigation measures, such as plant selection, the
installation of temporary noise barriers around the perimeter of the Proposed
Development Site to reduce noise levels by up to 10dB (assuming the proposed
Severnside Energy Recovery Centre is not built by then and does not deliver this
level of screening), and by scheduling works, where practicable and deemed
necessary following a review of the detailed design, to minimise total noise
emissions, construction noise levels can be reduced to bring the significance of
effect of this activity at the Severn Estuary to minor adverse or negligible.
Further mitigation measures and Best Practicable Means are discussed later in
this section.
12.5.7. Noise will also be emitted during the construction of the associated infrastructure,
which comprises the proposed cooling water pipeline and electrical connection.
12.5.8. The noise emissions from the installation of the electrical connection will occur
within the existing Seabank 1 & 2 site and should therefore to a degree be
masked by the existing background noise and screened by these existing
buildings. Any HDD activities on the Proposed Development Site (if the electrical
cable is routed beneath Seabank 1 & 2) have been included as part of the onsite
works assessed above and determined to be negligible significance.
12.5.9. The estimated free-field construction noise levels at various distances from the
cooling water pipeline are provided in Table 12-12.
Seabank 3 PEI Report – Chapter 12 Noise and Vibration
May 2014 Page 12-18
Table 12-12: Predicted Free-Field Daytime Construction Noise Levels associated with the Cooling Water Pipeline Construction
Construction activity
Predicted total daytime construction noise level LAeq,1h dB at various distances (metres)
10m 25m 50m 75m 100m 125m 150m 175m 200m 250m 300m
Earthworks 74 70 65 63 60 58 56 54 53 44 42
Excavation of pipeline
77 73 68 65 62 60 58 57 56 46 45
Pipeline Installation
77 70 64 60 57 55 54 53 51 42 41
Backfilling of pipeline
76 72 67 65 62 60 58 56 55 46 44
350m 400m 450m 500m 600m 700m 800m 900m 1km 1.2km 1.4km
Earthworks 41 39 38 44 42 41 40 38 37 36 34
Excavation of pipeline
43 42 41 47 45 43 42 41 40 38 37
Pipeline Installation
39 38 37 43 42 40 39 38 37 35 34
Backfilling of pipeline
43 41 40 46 44 43 41 40 39 38 36
12.5.10. The closest residential receptors to the proposed cooling water pipeline corridor
are located approximately 800m from the southernmost point of the corridor.
Estimated noise levels at this receptor (and all others) fall well below the BS 5228
minimum daytime Threshold Value of 65dB LAeq,1h and night-time Threshold Value
of 45dB LAeq,1h. At Elmington Manor Farm (1.1km from any pipeline construction
works), the estimated cooling water pipeline construction noise levels fall well
below the 65dB LAeq,1h daytime threshold and the 50 dB LAeq,1h night-time
threshold.
12.5.11. The significance of effect for construction noise during the cooling water pipeline
construction upon the closest residential receptors is therefore assessed as
negligible.
12.5.12. At Chittening Warth / Severn Estuary, which is located 200m from the closest part
of the cooling water pipeline construction works, predicted levels will be
approximately 56dB LAeq,1h. This is slightly higher than the existing ambient noise
levels experienced, therefore the magnitude of change is assessed as minor
adverse.
Construction Vibration
12.5.13. The closest residential receptors to the Proposed Development Site are located
approximately 1.1km away. BS 5228 Part 2 provides historical measured
vibration data for different types of piling and indicates that at 30m from driven
Seabank 3 PEI Report – Chapter 12 Noise and Vibration
May 2014 Page 12-19
piling a vibration level of 0.88mm/s ppv is likely. A level of 0.88mm/s ppv at 30m
gives a vibration level of less than 0.1mm/s ppv at the nearest residential
receptor to the Proposed Development Site, indicating that vibration from piling
activities will not be perceptible.
12.5.14. Vibration from piling is therefore unlikely to result in a significant effect at
residential properties, particularly if other methods of piling that produce lower
levels of vibration, such as CFA (bored) piling, are used. The significance of this
potential effect is therefore considered to be negligible.
Construction Traffic
12.5.15. Road traffic estimates have been developed for the expected peak year of
construction, which is 2019 based on the current project programme.
12.5.16. Predictions have been made using the methodology given in CRTN whereby, in
the absence of residential or habitat receptors immediately adjacent to these
road links, changes in noise levels from increases in road traffic have been
predicted at a distance of 10m from each road link.
12.5.17. Road traffic noise levels have been predicted for two scenarios; the 2019
baseline (with no construction traffic) and 2019 including the peak month of
construction traffic. The predicted noise levels and calculated increase at the
closest receptors are presented in Table 12-13 below, with the significance of
effect taken from Table 12-5.
Table 12-13: Predicted Noise Increases due to Construction Traffic
Link Details 2019 Predicted LA10,18h dB Increase in Noise Level dB
Significance of Effect Baseline With
Construction
1 A403 - between Kings Road Avenue and Unclassified Road
71.5 71.6 0.1 Negligible
2 A403 - between B4055 and M48
68.8 68.8 0.0 Negligible
3 A403 - between 'unclassified road' and B4064
71.8 71.9 0.1 Negligible
4 M48 - between Junction 1 and the M4 (Junction 21)
76.5 76.5 0.0 Negligible
5 M5 - between Junction 15/20 (M5/M4) and Junction 14 M5
82.4 82.3 0.0 Negligible
6 A4 - between A4162 and A4176
72.4 72.4 0.0 Negligible
7 M4 - between Junction 20/15 M4/M5 and Junction 19 M4/M32
83.4 83.4 0.0 Negligible
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May 2014 Page 12-20
Link Details 2019 Predicted LA10,18h dB Increase in Noise Level dB
Significance of Effect Baseline With
Construction
8 A403 – junction A403 Severn Road/ Severn Road and Chittening Road
71.7 71.7 0.0 Negligible
9 A403 – outside existing Seabank access
74.1 74.1 0.0 Negligible
12.5.18. The increase in road traffic noise levels as a result of increased traffic during
construction will result in an imperceptible magnitude of change. The predicted
effect of traffic noise is anticipated to be negligible. This is despite having based
the assessment on the peak month of construction traffic; the effect during other
months is predicted to be less.
Operational Noise Levels
CCGT and Peaking Plant Noise
12.5.19. The predicted worst-case free-field operational noise levels at the locations of the
receptor facades, for both the single and multi-shaft options are presented in
Table 12-14.
12.5.20. All predictions include the operation of the peaking plant units, and assume their
operation for 100% of the assessment period; in practice they are likely to
operate for only a fraction of the year and therefore this is an overestimate. The
current best estimate is that the CCGT units would operate on average 31% over
the station lifetime and the peaking plant will be capped at a maximum 1,500
hours per year operation. Since the peaking plant can comprise either OCGT or
reciprocating engines, two scenarios have been modelled: 2 x 120MW gas
turbines or 13 x 18MW reciprocating engines, both representing up to 240MW of
peaking plant units.
12.5.21. It has been assumed that during the detailed design of the Proposed
Development residual potential noise impacts will be further mitigated by design,
for example through the additional enclosure of the engines within buildings. For
this assessment it has therefore been assumed that the internal reverberant
noise levels within the peaking plant units will be comparable for both the gas
turbine and the reciprocating engine options.
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May 2014 Page 12-21
Table 12-14: Predicted Operational Noise Levels
Receptor Predicted Operational Noise Level LAeq,1h dB
Option 1 – Single Shaft Option 2 – Multi Shaft
Daytime
R1: Barnacre 28 27
R2: Elmington Manor Farm 34 31
R3: Orchard Cottage 33 30
R4: 104 Marsh Common Road 32 29
R5: 2 Severnwood Gardens 35 37
R6: Chittening Warth* 40 42
Night-time
R1: Barnacre 29 29
R2: Elmington Manor Farm 35 31
R3: Orchard Cottage 34 31
R4: 104 Marsh Common Road 32 30
R5: 2 Severnwood Gardens 36 37
R6: Chittening Warth* 40 42
* Noise levels at Chittening Warth are predicted to be higher from the operation of the multi-shaft option due to the
location of the air inlet filters.
12.5.22. Employing the assessment methodology given in BS 4142, the likelihood of
complaint at each residential receptor has been assessed, based on the
calculated Rating Level (which includes a +5dB penalty for a worst-case
assessment) and measured background noise level at the receptor.
12.5.23. The BS 4142 assessment for the receptors R1 to R5 is presented in Table 12-15
for the single-shaft option and in Table 12-16 for the multi-shaft option. Receptor
R6 results are presented in Table 12-17.
Table 12-15: BS 4142 Assessment with 5dB Penalty – Single Shaft Configuration
Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T
dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment Significance
Daytime
R1: Barnacre
45 28 33 -12 Complaints unlikely Negligible
R2: Elmington Manor Farm
45 34 39 -6 Less than marginal significance
Negligible
R3: Orchard Cottage
45 33 38 -7 Less than marginal significance
Negligible
R4: 104 51 32 37 -14 Complaints unlikely Negligible
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May 2014 Page 12-22
Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T
dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment Significance
Marsh Common Road
R5: 2 Severnwood Gardens
54 35 40 -14 Complaints unlikely Negligible
Night-time
R1: Barnacre
38 29 34 -4 Less than marginal significance
Negligible
R2: Elmington Manor Farm
38 35 40 +2 Marginal Significance Minor adverse
R3: Orchard Cottage
38 34 39 +1 Marginal Significance Minor adverse
R4: 104 Marsh Common Road
38 32 37 -1 Less than marginal significance
Negligible
R5: 2 Severnwood Gardens
47 36 41 -6 Less than marginal significance
Negligible
Table 12-16: BS 4142 Assessment with 5dB Penalty – Multi Shaft Configuration
Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T
dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment
Significance
Daytime
R1: Barnacre
45 27 32 -13 Complaints unlikely Negligible
R2: Elmington Manor Farm
45 31 36 -9 Less than marginal significance
Negligible
R3: Orchard Cottage
45 30 35 -10 Complaints unlikely Negligible
R4: 104 Marsh Common Road
51 29 34 -17 Complaints unlikely Negligible
R5: 2 Severnwood Gardens
54 37 42 -12 Complaints unlikely Negligible
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May 2014 Page 12-23
Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T
dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment
Significance
Night-time
R1: Barnacre
38 29 34 -4 Less than marginal significance
Negligible
R2: Elmington Manor Farm
38 31 36 -2 Less than marginal significance
Negligible
R3: Orchard Cottage
38 31 36 -2 Less than marginal significance
Negligible
R4: 104 Marsh Common Road
38 30 35 -3 Less than marginal significance
Negligible
R5: 2 Severnwood Gardens
47 37 42 -5 Less than marginal significance
Negligible
12.5.24. Based on the methodology given in BS4142, for the daytime period, the single-
shaft configuration is expected to result in ‘complaints unlikely to ‘less than
marginal significance’ at nearby residential receptors. At night-time, the effect
ranges from ‘less than marginal significance’ to ‘marginal significance’ prior to
mitigation.
12.5.25. Prior to additional mitigation measures (which are discussed later in this chapter),
the worst-case predicted noise levels from the operation of the single-shaft
configuration results in negligible effects during the daytime and negligible to
minor adverse effects during the night-time.
12.5.26. For the daytime period, the multi-shaft configuration is expected to result in
‘complaints unlikely’ to ‘less than marginal significance’ at nearby residential
receptors. At night-time, the effect is ‘less than marginal significance’.
12.5.27. Prior to additional mitigation measures (which are discussed later in this chapter),
the worst-case predicted noise levels from the operation of the multi-shaft
configuration results in negligible effects during both daytime and night-time
periods.
12.5.28. Analysis of the source noise contributions for each plant configuration indicates
that the dominant contributing noise sources for both configurations are the
hybrid cooling water system and the air inlet filters to the turbine halls.
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May 2014 Page 12-24
12.5.29. The predicted overall operational noise levels at a location representative of
Chittening Warth / Severn Estuary (R6) are presented in Table 12-17, along with
the estimated significance of effect.
Table 12-17: Predicted Operational Noise Levels at Chittening Warth prior to Additional Mitigation
Time of Day
Existing Ambient Noise Level, LAeq dB*
Single Shaft Multi Shaft
Overall Noise Level LAeq dB
Change Significance of Effect
Overall Noise Level LAeq dB
Change Significance of Effect
Daytime 52 52 0 Negligible 52 0 Negligible
Night-time 45 46 +1 Negligible/minor adverse
47 +2 Minor adverse
* This level has been calculated using a distance correction calculation and assuming the dominant baseline noise source is from road traffic on Severn Road.
12.5.30. The significance of predicted changes in daytime noise levels is assessed as
negligible for both the single-shaft and multi-shaft options.
12.5.31. The significance of predicted changes in night-time noise levels is assessed as
negligible/minor adverse for the single-shaft option and minor adverse for the
multi-shaft option prior to additional mitigation.
12.5.32. The operation of the Proposed Development may also require the use of
emergency sirens. These will sound during times of emergency and during
routine testing. It is understood that some existing surrounding industrial sites are
COMAH sites which also have operational sirens which are tested regularly. As a
result of their expected short term use, in emergency situations only, the noise
effects due to the operation of sirens at the Proposed Development Site are
unlikely to be significant and are assessed as negligible.
Operation of the Associated Infrastructure
12.5.33. The operation of the cooling water pipeline, electricity cables and associated
pump house and substation is not anticipated to emit high levels of noise from
the Other DCO Land. In addition, there are no residential receptors within close
proximity. Therefore, an operational noise assessment has not been undertaken
for the associated infrastructure and the effects are assessed as negligible.
Operational Traffic
12.5.34. The operation of the development is not predicted to produce significant amounts
of additional traffic. There will be up to 40 workers onsite during operation
(spread over three 8 hour shifts), plus the occasional deliveries. This is
considerably less traffic than the construction stage, which was assessed as
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May 2014 Page 12-25
negligible, and hence, an operational road traffic noise assessment has therefore
been scoped out and is assumed to be of negligible significance.
Mitigation Measures
Construction Noise Mitigation
12.5.35. With regards to residential receptors, as predicted construction noise levels will
easily comply with the daytime and night-time Threshold Levels as given in
BS 5228, no mitigation is required. However, the contractor will follow Best
Practicable Means to further reduce the noise effect upon the local community.
This will include the following:
• All construction plant and equipment will comply with EU noise emission
limits;
• Proper use of plant with respect to minimising noise emissions and
regular maintenance. All vehicles and mechanical plant used will be fitted
with exhaust silencers and shall be maintained in good efficient working
order;
• Selection of good plant, where appropriate (in other words, taking into
account noise emissions when selecting plant). Compressors will be
‘sound reduced’ models fitted with properly lined and sealed acoustic
covers which should be kept closed whenever the machines are in use
and all ancillary pneumatic percussive tools will be fitted with mufflers or
silencers of the type recommended by the manufacturers;
• Machines in intermittent use will be shut down in the intervening periods
between work or throttled down to a minimum;
• Where possible, ancillary plant such as generators, compressors and
pumps will be positioned so as to cause minimum noise disturbance, i.e.
furthest from receptors or behind close boarded noise barriers. If
necessary, acoustic enclosures will be provided and/or acoustic
shielding; and
• Construction contractors will be obliged to adhere to the codes of
practice for construction working and piling given in BS 5228 and the
guidance given therein minimising noise emissions from the Proposed
Development Site.
12.5.36. Consideration will be given to monitoring and acting upon noise complaints in the
CEMP during the construction phase.
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Operational Noise Mitigation
12.5.37. The primary mitigation for noise from fossil fuel generating stations is through
good design. This includes enclosure of plant and machinery in noise reducing
buildings wherever possible to minimise the potential for operations to create
noise. Noise from gas turbines will be mitigated by attenuation of inlets and
exhausts to reduce any risk of low frequency noise transmission.
12.5.38. The assessment has taken a worst-case approach, with the employment of a +5
dB(A) correction to account for possible tonal components to the emitted noise
from the plant.
12.5.39. At the detailed design stage, post-consent, the plant will be designed such that
any significant tonal components are eliminated through, for example, the use of
silencers, enclosures and appropriate specification building cladding. As
mitigation measures should remove the tonal component the +5dB penalty does
not need to be applied.
12.5.40. Tables 12-18 and 12-19 present the findings of a BS 4142 assessment following
the implementation of these mitigation measures.
Table 12-18: BS 4142 Assessment with Mitigation – Single Shaft
Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment
Significance
Daytime
R1: Barnacre
45 28 28 -17 Complaints unlikely
Negligible
R2: Elmington Manor Farm
45 34 34 -11 Complaints unlikely
Negligible
R3: Orchard Cottage
45 33 33 -12 Complaints unlikely
Negligible
R4: 104 Marsh Common Road
51 32 32 -19 Complaints unlikely
Negligible
R5: 2 Severnwood Gardens
54 35 35 -19 Complaints unlikely
Negligible
Night-time
R1: Barnacre
38 29 29 -9 Less than marginal significance
Negligible
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Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment
Significance
R2: Elmington Manor Farm
38 35 35 -3 Less than marginal significance
Negligible
R3: Orchard Cottage
38 34 34 -4 Less than marginal significance
Negligible
R4: 104 Marsh Common Road
38 32 32 -6 Less than marginal significance
Negligible
R5: 2 Severnwood Gardens
47 36 36 -11 Complaints unlikely
Negligible
Table 12-19: BS 4142 Assessment with Mitigation – Multi Shaft
Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment
Significance
Daytime
R1: Barnacre
45 27 27 -18 Complaints unlikely
Negligible
R2: Elmington Manor Farm
45 31 31 -14 Complaints unlikely
Negligible
R3: Orchard Cottage
45 30 30 -15 Complaints unlikely
Negligible
R4: 104 Marsh Common Road
51 29 29 -22 Complaints unlikely
Negligible
R5: 2 Severnwood Gardens
54 37 37 -17 Complaints unlikely
Negligible
Night-time
R1: Barnacre
38 29 29 -9 Less than marginal significance
Negligible
R2: Elmington Manor Farm
38 31 31 -7 Less than marginal significance
Negligible
R3: Orchard 38 31 31 -7 Less than marginal
Negligible
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Receptor Measured LA90 dB
Predicted LAeq dB
Rating Level LAr,T dB
Difference between Rating Level and LA90 dB
BS 4142 Assessment
Significance
Cottage significance
R4: 104 Marsh Common Road
38 30 30 -8 Less than marginal significance
Negligible
R5: 2 Severnwood Gardens
47 37 37 -10 Complaints unlikely
Negligible
12.5.41. Based on the methodology given in BS4142, for the daytime period, the single-
shaft configuration is expected to result in ‘complaints unlikely’ at nearby
residential receptors. At night-time, the effect ranges from ‘complaints unlikely’ to
‘less than marginal significance’.
12.5.42. The predicted noise levels from the operation of the single-shaft configuration
results in negligible effects during both the daytime and night-time periods.
12.5.43. For the daytime period, the multi-shaft configuration is expected to result in
‘complaints unlikely’ at nearby residential receptors. At night-time, the effect
ranges from ‘complaints unlikely’ to ‘less than marginal significance’.
12.5.44. The predicted noise levels from the operation of the multi-shaft configuration
results in negligible effects during the daytime and night-time periods.
12.5.45. The predicted Rating Levels for both the single-shaft and multi-shaft options meet
SGC’s criterion of equal to, or below, background noise levels at all receptors.
12.5.46. Analysis of the source noise contributions for each plant configuration indicates
that the dominant contributing noise sources for both configurations are still the
hybrid cooling water system and the air inlet filters to the turbine halls.
12.5.47. As the dominant contributing noise sources at the surrounding residential
receptors are the hybrid cooling water system and air inlet filters, the irregular
operation of the peaking plant is unlikely to attract the attention of residents at
these properties. It is noted that, whilst the peaking plant may operate at any
time, it is highly likely that it will only be in operation during the most demanding
parts of the daytime period, when predicted Rating Levels are a minimum of 6 dB
below the prevailing background noise levels.
12.5.48. The assessment of noise impacts upon Chittening Warth is based on the change
in the noise level at the receptor as the assessment methodology given in
BS4142 is not appropriate. Therefore the assessment of noise impacts with
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May 2014 Page 12-29
mitigation measures will be the same as the assessment without mitigation.
However, an assessment of noise impacts at Chittening Warth with mitigation has
been included for completeness.
12.5.49. The predicted overall operational noise levels at a location representative of
Chittening Warth / Severn Estuary (R6) are presented in Table 12-20, along with
the estimated significance of effect.
Table 12-20: Predicted Operational Noise Levels at Chittening Warth – With Mitigation
Time of Day
Existing Ambient Noise Level, LAeq dB*
Single Shaft Multi Shaft
Overall Noise Level LAeq dB
Change Significance of Effect
Overall Noise Level LAeq dB
Change Significance of Effect
Daytime 52 52 0 Negligible 52 0 Negligible
Night-time 45 46 +1 Negligible/minor adverse
47 +2 Minor adverse
* This level has been calculated using a distance correction calculation and assuming the dominant
baseline noise source is from road traffic on Severn Road.
12.5.50. The significance of predicted changes in daytime noise levels is assessed as
negligible for both the single-shaft and multi-shaft options.
12.5.51. The significance of predicted changes in night-time noise levels is assessed as
negligible/minor adverse for the single-shaft option and minor adverse for the
multi-shaft option.
12.5.52. Acoustic modelling and assessment will form an integral part of the detailed
design process. As the design progresses, efforts will be made to reduce noise
levels further, where practicable, to provide negligible effects at all receptors.
12.5.53. A procedure shall be put in place once the Proposed Development is operational
to receive and act on any noise complaints.
12.6. Decommissioning Phase
12.6.1. It is envisaged that the Proposed Development will have a design life of 30 years
and a possible operating life beyond this depending on the number of running
hours.
12.6.2. It is anticipated that the decommissioning phase would generate comparable
noise to the construction works, and would decommission the cooling water
pipeline in-situ, avoiding the need for extensive excavation works. The effect of
the decommissioning phase is therefore expected to be similar in nature to the
construction activities, albeit of a shorter duration.
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12.6.3. Decommissioning is therefore expected to generally lead to a negligible effect
on residential and habitat receptors.
12.7. Residual Effects
12.7.1. A summary of the residual effects, assuming implementation of the proposed
mitigation, is presented in Table 12-21 below.
Table 12-21: Summary of Residual Effects
Description Nature of effect BS4142 Rating Significance of Effect
Construction Noise from Standard Activities – Residential Receptors
Temporary N/A Negligible
Construction Noise from Standard Activities – Ecological Receptors
Temporary N/A Minor
Construction Traffic Temporary N/A Negligible
Construction Vibration
Temporary N/A Negligible
Operational Noise (single or multi shaft)
Permanent
‘complaints unlikely’ to ‘less than marginal significance’
Negligible
Decommissioning Temporary N/A Negligible
12.7.2. This chapter has provided an assessment of the noise and vibration impacts
likely to arise as a result of the construction and operation of the Proposed
Development.
12.7.3. Noise levels were predicted at the facades of the closest residential receptors to
the Proposed Development Site, and at a location representative of Chittening
Warth / Severn Estuary to consider the nearest habitat receptors.
12.7.4. The predicted construction noise levels were assessed against the daytime and
night-time Threshold Values derived from the BS 5228 ABC method for
assessing the noise effects from construction activities. Predictions have shown
that noise levels from standard construction activities will fall below the Threshold
Values at the selected residential receptors during all construction activities
during both daytime and night-time periods. A negligible significance of effect
has therefore been predicted.
12.7.5. The contractor will employ Best Practicable Means in order to ensure that
construction noise is kept to a minimum.
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May 2014 Page 12-31
12.7.6. Noise levels from construction traffic during the construction phase are not
expected to result in a perceptible noise effect. A negligible adverse significance
of effect has therefore been predicted for road traffic.
12.7.7. The operational noise effects were predicted using the noise modelling software
package SoundPLAN. This software package allows the creation of a 3D model
of the Proposed Development Site and surrounding area to allow the propagation
of noise to be predicted.
12.7.8. The predicted noise levels were assessed against the average background noise
level recorded during good weather.
12.7.9. With the implementation of mitigation measures, an overall significance of effect
of negligible is predicted for both the single-shaft and multi-shaft options.
12.8. Cumulative Effects
12.8.1. In order to understand the potential effects of the Proposed Development on the
noise climate it is important to consider potential cumulative effects. Cumulative
effects may be caused by an interaction of different effects to constitute a larger,
more significant effect, such as increased noise and vibration at the closest noise
sensitive properties due to other future developments.
12.8.2. Several developments were identified as potentially causing cumulative effects
and these are listed in Chapter 7: Assessment Methodology. The future
cumulative baseline would include extensive existing and proposed industrial
developments located to the west of the M49.
12.8.3. With regards to cumulative construction noise impacts upon residential receptors,
predicted noise levels from the construction of the Proposed Development fall
well below the ABC Threshold Values given in BS5228. As the predicted
construction levels are so low, construction noise from the Proposed
Development will make a negligible contribution to any cumulative construction
noise levels associated with any other schemes.
With mitigation in place to control tonal noise emissions from the operational
Proposed Development, the worst-case Rating Level is 3dB below the measured
background level. For the Severnside Energy Recovery Centre and the Viridor
Avonmouth Energy from Waste (EfW) facility, predicted Rating Levels were
significantly below the measured background noise level, therefore the
cumulative noise impact upon residential receptors is likely to be no greater than
the noise impacts given in this chapter. Assuming that the Avon Power Station
scheme is designed to control noise to the same degree as the Proposed
Development the cumulative worst-case Rating Level will be 0dB above the
measured background level. This is assessed as of ‘less than marginal
Seabank 3 PEI Report – Chapter 12 Noise and Vibration
May 2014 Page 12-32
significance’ in BS 4142, which results in a cumulative significance of effect of
negligible.
12.9. Impacts and Effects yet to be Determined
12.9.1. There are no impacts and effects yet to be determined, however, the scheme
design may be subject to change prior to submission of the final DCO application.
Any changes that lead to differing or new impacts and effects will be assessed
within the final ES, along with the reasons for the change.
12.9.2. It is also possible that the baseline conditions will change between the
preparation of this PEI Report and the final ES; noise conditions are dynamic and
evolve over time. The Proposed Development Site is currently subject to
excavation, top soil stripping, and levelling in certain areas in order for third
parties to deliver the Spine Access Road and new channel for the Red Rhine,
which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7:
Assessment Methodology. A haul road is also being constructed through the
middle of the Proposed Development Site to enable access by third party from
the roundabout to the east of the Site to the Severnside Energy Recovery Centre
to the west. These works onsite are being undertaken by other developers, under
extant planning permissions and are separate to the Proposed Development.
12.9.3. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changes
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
12.10. References
Ref. 12-1 BS 5228: 2009+A1: 2014 ‘Code of Practice for Noise and Vibration
on Construction and Open Sites, Part 1: Noise’. British Standards
Institute.
Ref. 12-2 BS 4142: 1997, ‘Method for rating industrial noise affecting mixed
residential and industrial areas’.
Ref. 12-3 ‘Guidelines for Community Noise’, World Health Organisation, 1999.
Ref. 12-4: ISO 9613-2: 1996 ‘Attenuation of sound during propagation outdoors’.
Ref. 12-5 Highways Agency et al. (2008). Design Manual for Roads and
Bridges Volume 11 Section 3 Part 7 ‘Noise and Vibration’.
Ref. 12-6 CRTN Department of Transport and the Welsh Office (1988).
Calculation of Road Traffic Noise.
Seabank 3 PEI Report – Chapter 12 Noise and Vibration
May 2014 Page 12-33
Ref. 12-7 British Standard BS 7445: 2003 ‘Description and Measurement of
Environmental Noise’, British Standards Institute, 2003.
Seabank 3 PEI Report – Chapter 13 Ground Conditions
May 2014 Page 13-1
13. Ground Conditions
13.1. Introduction
13.1.1. This chapter of the PEI Report presents an assessment of the potential effects
of the Proposed Development and associated infrastructure on land quality and
groundwater resources.
13.1.2. It identifies key land contamination receptors and their sensitivities, including
the principal water resources, and addresses the direct and indirect effects of
the Proposed Development and associated infrastructure on these receptors.
The assessment of the predicted magnitude of the effects is made in the
context of the existing site conditions (baseline conditions), predicted
conditions during site preparation and construction works, the conditions
expected once the Proposed Development and associated infrastructure is
operational and during eventual future decommissioning. The need for
mitigation measures is addressed where applicable, and residual effects
following their implementation have been identified.
13.1.3. The previous land use history and sensitive receptors within the vicinity of the
Proposed Development Site have been identified. This chapter includes a
Conceptual Site Model (CSM), which establishes relevant source – pathway –
receptor pollutant linkages for the potential land contamination issues
identified.
Consultation
13.1.4. Table 13-1 provides an overview of responses from key consultees during the
Scoping phase.
Table 13-1: Relevant Scoping Opinion Responses
Stakeholder Comment Addressed within the Report
BCC
Recommends remedial investigation along the route of the proposed cooling water pipeline as the study corridor passes through land known to have been subject to contaminating land uses and sensitive receptors (rhines: man-made surface water drainage ditches).
Ground investigation of cooling water pipeline route is discussed in see section 13.4.
EA
The EIA should consider the construction phase and post-construction phase risks to controlled waters, i.e. dewatering and or the construction of deep excavations.
Both construction and post-construction phase risks to controlled waters have been considered in throughout this chapter.
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May 2014 Page 13-2
Stakeholder Comment Addressed within the Report
The effect of the development on any private water supplies in the area must be considered.
There is no licenced groundwater abstractions registered within the vicinity of the Proposed Development Site or associated infrastructure. This is discussed within the chapter.
Any controlled water risk assessments completed within the EIA should be based on Environmental Quality Standards (EQS) appropriate for the site context, i.e. adjacent to the Severn Estuary SPA. EQS for the assessment of rhines and ditches on site should be the same as those for the SPA.
No controlled water risk assessments have been carried out for this PEI Report as, at the time of writing, the results of the ground investigation, including chemical analyses, were not available. This data and the need for a controlled water risk assessment will be presented in the final ES.
13.1.5. Additional informal consultation has been carried out since receipt of the
Scoping Opinion from the Planning Inspectorate in February 2013, with
Environmental Health Officers of BCC and SGC, and the EA, in respect of
baseline land quality conditions and the proposed ground investigation
specification. SGC and BCC confirmed they did not have any comments on the
scope of work, although BCC noted “The proposed route will have potential
contamination issues as it passes through and by historical areas of landfilling,
industrial activity etc”. This comment related to the electrical connection
corridor presented at Scoping however, which has been modified to avoid the
historical area of landfilling.
13.1.6. The EA responded on the 5 December 2013 with the following comments;
• The developer should ensure that the ground investigation carried out is
adequate to inform contaminated land issues as well as geotechnical
ones,
• To inform the risk assessment for controlled waters [we would
recommend that] the soil samples are analysed for leachable
contaminants. Where possible it is recommended that the groundwater
be sampled.
13.1.7. The approach taken to the ground investigation and risk assessment of the
Proposed Development Site is outlined in section 13.2 of this chapter.
However, in summary, following the review of Phase 1 desktop information, it
was determined that the majority of the Proposed Development Site comprises
previously undeveloped land, with the exception of the former railway and farm
buildings, and as such the location of the exploratory holes was driven by
geotechnical requirements.
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May 2014 Page 13-3
13.1.8. With reference to the EA comment regarding leachate testing, this was not
undertaken on soil samples collected during the ground investigation of the
Proposed Development Site, as groundwater was found to be readily available
within each of the installed boreholes and the results of direct groundwater
sampling are considered to be of more use than leachate results when
considering the risk to controlled waters.
13.2. Legislation and Planning Policy Context
13.2.1. Potential redevelopment on areas of brownfield land must take into account the
regulatory context of the work, provide information that it is fit for purpose, and
be in accordance with good practice and relevant guidance. An environmental
assessment of the condition of the DCO Site must not only consider the
potential receptors of human health and controlled waters, but also include a
review of the relevant legislation and planning policy that applies to the DCO
Site and its immediate environs.
13.2.2. Chapter 8: Planning Policy Context sets out the overarching policy framework
relevant to the Proposed Development. The final ES will include a detailed
description of the policies relevant specifically to the ground conditions
assessment. For the Purposes of this report these are summarised in Appendix
D, Volume II of this PEI Report.
13.3. Assessment Methodology and Significance Criteria
Assessment Methodology
13.3.1. A variety of data sources have been consulted, such as published maps,
commercially available environmental database records, including an
Envirocheck Report obtained from Landmark Information Group (Ref. 13- 1)
and available third party technical reports. Each data source is referenced as
appropriate in the following sections of this chapter.
13.3.2. URS has undertaken ground investigation (GI) works within the Proposed
Development Site. No GI has been undertaken within the CCR Site or the
Other DCO Land, which will include the proposed electrical connection and
proposed water pipeline corridor. The CCR Site will be reinstated to grassland
following construction, and the electrical connection and cooling water pipeline
are not sensitive to, and therefore should not be affected by, contamination
(although localised remediation or removal of soils may be required).
13.3.3. The GI was designed by URS on behalf of the Applicant and the location of the
exploratory holes was determined by the layout of the Proposed Development
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May 2014 Page 13-4
at the time of planning the survey (in July 2013) and also to target the railway
track area in the north of the Proposed Development Site. The GI comprised:
• The excavation of 7 boreholes using shell and auger with rotary follow
on techniques to a maximum depth of 26.15m bgl;
• The excavation of 12 Trial Pits using a JCB 3CX excavator, with
California Bearing Ratio (CBR) testing carried out in each;
• Twenty one Cone Penetrometer Tests (CPT) including dissipation tests
were carried out using a truck mounted CPT rig;
• In-situ geotechnical testing in all boreholes;
• Collection of soil samples for geotechnical laboratory analysis;
• Soil, groundwater and surface sampling and analysis, and;
• Ground gas monitoring.
13.3.4. The Phase II Geotechnical and Contamination Assessment report on the GI is
included in Appendix I Part 4, Volume II of this PEI Report and information
obtained from the GI has been included in the appropriate baseline sections
below.
13.3.5. A site visit along the cooling water pipeline was undertaken by URS on 18
November 2013. Information from that site visit is included as appropriate
below.
13.3.6. The EA / Defra’s Contaminated Land Report 11 (CLR11) ‘Model Procedures for
the Management of Land Contamination’ (Ref. 13-2) provides for staged and
risk-based data interpretation. This commences with a Preliminary Risk
Assessment (PRA, also known as Stage 1 risk assessment), which is normally
a desk based assessment to develop an initial Conceptual Site Model (CSM) to
identify any source-pathway-receptor Pollutant Linkages that might apply at the
Site and would be used to define any potential risks. Where potential risks are
identified, the CSM would be used to design an intrusive site investigation to
acquire additional data on the pollutant linkages identified.
13.3.7. Where site investigation data confirms the presence of contaminants of
concern, the laboratory analytical data are screened against Generic
Assessment Criteria (GAC), defined through the process of a Stage 2 Generic
Quantitative Risk Assessment (GQRA). GAC are conservative in nature and
are used to screen out risks that are unlikely to represent an “unacceptable
risk” to the receptors defined in the CSM – the GAC are set to ensure that, if
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they are not exceeded, it is extremely unlikely that relevant receptors will be
exposed to significant levels of risk.
13.3.8. In cases where Stage 2 GQRA GAC are exceeded, it is normally appropriate to
proceed to Stage 3 Detailed Quantitative Risk Assessment (DQRA) to define
Site Specific Assessment Criteria (SSAC). Stage 3 DQRA will often require that
additional site investigation is undertaken to collect specific additional data to
refine the risk assessment process and determine the need for further action,
such as land and / or groundwater remediation.
Significance Criteria
13.3.9. A review of baseline conditions at the DCO Site was undertaken to evaluate
the nature of potential effects associated with the Proposed Development and
associated infrastructure. The magnitude of potential changes (using worst
case scenarios) during the operational, construction and decommissioning
phases of the development have been qualitatively described and categorised,
as set out in Table 13-2. The magnitude of potential changes is assessed
against baseline conditions, prior to the consideration of mitigation measures
and includes consideration of the sensitivity of the receptor.
Table 13-2: Criteria to Determine Magnitude of Change
Magnitude of Change
Criteria Example / Description
High
Results in loss of an attribute and is likely to cause exceedances of statutory objectives and/or breaches of legislation
Contamination of a potable source of abstraction
Medium
Results in a change to the integrity of attribute or the loss of part of attribute, possibly with/ without exceedances of Statutory objectives or with/ without breaches of legislation.
Reduction in the value of the feature
Low
Results in a small change to an attribute that does not result in a change to its integrity or the loss of part of the attribute.
Measurable changes in attribute, but of limited size and/or proportion
Neutral Results in no discernible change or a change on attribute of insufficient magnitude to affect the use / integrity
Discharges to watercourse but no significant loss in quality of the feature
13.3.10. The significance of residual effects is assessed in accordance with criteria in
Table 13-3 and reflects the effect after incorporation of mitigation methods to
be applied in the implementation of the Proposed Development and associated
infrastructure.
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13.3.11. The criteria for classifying significance of effects are summarised in Table 13-3.
Moderate and major effects are considered ‘significant’ for the purpose of this
assessment.
Table 13-3: Description of Significance of Effects
Significance Description
Major Adverse
Considerable detrimental effect (by extent, duration or magnitude) of more than local significance or in breach of recognised acceptability / legislation / policy standards, which is clearly significant.
Moderate Adverse Limited detrimental effect (by extent, duration or magnitude) that may be considered significant.
Minor Adverse Slight, very short or highly localised detrimental effect.
Negligible No appreciable effect on the attribute, or the attribute of negligible importance
Minor Beneficial Slight, very short or highly localised beneficial effect.
Moderate Beneficial Limited beneficial effect (by extent, duration or magnitude) that may be considered significant.
Major Beneficial Considerable beneficial effect (by extent, duration or magnitude) of more than local significance which is clearly significant.
13.3.12. Significance is also considered in terms of timescale (short, medium or long
term), permanence (reversible or permanent) and the geographic scale of the
effect (local, district, regional, national or international). For example, a short
duration release of suspended solids to controlled waters could result in the
temporary closure of a potable water abstraction (high magnitude), but the
effects would be expected to be short-term and fully reversible (minor adverse
significance).
13.3.13. These definitions take into account the large body of technical guidance that
has been produced in the UK for the assessment of ground conditions and
water resources by the Government (Defra and its predecessor departments),
and agencies such as the EA.
Key Parameters for Assessment
13.3.14. The Rochdale Envelope parameters outlined in Chapter 4: Project Description
do not significantly affect the input parameters utilised in either the operational
or construction ground conditions assessments, and consequentially the
outcome of these assessments will not vary. Therefore the assessment adopts
conservative (worst case) values where assumptions are necessary.
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13.4. Baseline Conditions
13.4.1. To assist the description of baseline conditions at the DCO Site, this section
first describes conditions within and surrounding the Proposed Development
Site and the electrical connection corridor within Seabank 1 & 2. It then
discusses the baseline conditions within the remainder of the DCO Site that will
contain the cooling water pipeline.
Proposed Development Site and Electrical Connection Corridor
13.4.2. The Proposed Development Site, as illustrated in Figure 3-2 (Volume III of this
PEI Report), is generally flat lying, undeveloped open grassland which is
drained by a network of rhines (drainage channels) and ditches that flow into
the Severn Estuary to the northwest. The Red Rhine is the largest drainage
channel within the Proposed Development Site and one of the main rhines in
this area. It currently flows in a southeast to northwest direction through the
middle of the Proposed Development Site.
13.4.3. It is understood that the current route of the Red Rhine is manmade and
historically the route has varied which is likely to have resulted in relic stream
channel features within the Proposed Development Site’s superficial and
bedrock geology.
13.4.4. There are currently no buildings or infrastructure on the Proposed Development
Site with the exception of the disused railway track in the northwest corner.
13.4.5. The land adjacent to the north of the Proposed Development Site comprises
the former Terra Nitrogen and ICI site, which was most recently used as a
fertiliser manufacturing plant. This site ceased to operate in 2008, and the
majority of the buildings associated with its former use have now been
demolished and it is now predominantly a cleared and level site of
hardstanding.
13.4.6. The land to the east and northeast of the Proposed Development Site
comprises undeveloped open fields with the M49 beyond. This land is subject
to extant planning permission from 1957/58 however and is currently subject to
land raising in preparation for a large scale industrial warehouse and
distribution complex.
13.4.7. The existing Seabank 1 & 2 generating station is located immediately
southwest of the Proposed Development Site with the land extending toward
the west currently comprising an overgrown grassed area part of which is a
demolished former gas storage facility. The proposed route of the electrical
connection crosses Seabank 1 & 2 to the Seabank Substation, which is
immediately south of this existing generating station.
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13.4.8. The land to the south of the Proposed Development Site, and west of Ableton
Lane, comprises a former landfill site which has been filled and raised to
approximately 2.5m above the existing ground level of the Proposed
Development Site. The land east of Ableton Lane, south of the CCR Site, is
undeveloped grassed fields known as Crooks Marsh.
13.4.9. Photographs of the Proposed Development Site and surrounding land use are
presented in Appendix I Part 2 and 3, Volume II of this PEI Report.
Site History and Development
13.4.10. Table 13-4 describes the history of the Proposed Development Site and the
part of the Other DCO Land that is proposed for the electrical connection within
Seabank 1 & 2. The table is based on published historical mapping provided
within the Envirocheck Report (Ref. 13-1).
Table 13-4: Historical Land Use within the Proposed Development Site and Other
DCO Land for Electrical Connection
Published Date
Map Scale Description
1881 1:2,500 The Proposed Development Site and electrical connection corridor comprises a series of undeveloped fields with field boundaries. An unnamed track is mapped across the centre of the Proposed Development Site from southwest to northeast. A second unnamed track runs southeast to northwest along the north western boundary, and a series of drainage ditches cross-cross the Proposed Development Site. Three unlabelled small rectangular features are shown adjacent to the west of the central track and one square feature is located at the centre of the southern Proposed Development Site.
1881 - 1965 1:2,500 Mapping does not show any significant changes in the Proposed Development Site and the electrical connection corridor.
1965 1:10,560 The Proposed Development Site remains largely unchanged until pre 1965 when a drain is developed through the centre of the site running southeast to northwest (the diversion of the Red Rhine).
A rail track has been developed in the northern section of the Proposed Development Site and continues toward the south east, extending into the CCR Site (it is labelled as dismantled by 1999 mapping).
The electrical connection corridor is largely unchanged although development has taken place immediately west which has resulted in field boundaries previously crossing the route having been removed and a new site perimeter established.
1970 1:1,250 The square feature along the southern boundary of the Proposed Development Site is labelled as Stowick Cottage. The three rectangular features are no longer present. The track running through the centre of the Proposed Development Site is labelled Ableton Lane. The remainder of the Site is largely unchanged.
1971 – 1972 1:2,500 A rectangular embankment feature is shown on the southern
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Published Date
Map Scale Description
and 1972 - 1977
boundary of the Proposed Development Site in the eastern section which may be associated with the development of a drainage ditch. The feature is not shown on mapping after 1992.
1975 1: 10,000 The drain developed through the centre of the Proposed Development Site is now labelled Red Rhine.
A drain appears to have been developed in line with the proposed route of the electrical connection.
1992 1:2,500 Stowick Cottage is no longer present. The remainder of the Proposed Development Site is largely unchanged.
2006 1: 10,000 Five pylons are now present on the Proposed Development Site. The remainder of the Site is largely unchanged.
The route of the proposed electrical connection is now located within the newly developed Seabank 1 & 2 site.
13.4.11. Although not shown on OS Maps, a number of gas and water pipelines are
understood to have been installed beneath the Proposed Development Site
during the construction of Seabank 1 & 2, in approximately 2000.
13.4.12. Table 13-5 describes the development of the land surrounding the Proposed
Development Site. It also describes the area surrounding the proposed
electrical connection corridor within Seabank 1 & 2. This table is based on
published historical mapping provided within the Envirocheck Report (Ref. 13-
1).
Table 13-5: Historical Development of Land Surrounding the Proposed Development Site and
Other DCO Land for the Electrical Connection
Published Date
Map Scale
Description
1881 1:2,500 The area surrounding the Proposed Development Site and the part of the Other DCO Land that will contain the electrical connection is shown to largely comprise undeveloped fields.
Stowick Farm is located 100m to the north of the Proposed Development Site.
Land adjacent to the south of the Proposed Development Site is largely undeveloped except for an unlabelled farm approximately 150m to the south.
The Red Rhine is shown approximately 150m northeast of the Proposed Development Site running in a southeast to northwest direction. An unlabelled farm is shown 100m north of the Red Rhine.
1903 1:2,500 Crook’s Marsh Farm is labelled approximately 100m to the north of the Proposed Development Site. The remainder of the surrounding areas remain largely unchanged.
1903 – 1965
1:10,000 Mapping does not show any significant changes of the land surrounding the Proposed Development Site and electrical connection.
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Published Date
Map Scale
Description
1965 (1965 – 1969)
1:10,000 The surrounding areas remain largely unchanged until the 1965 mapping which shows that extensive development has taken place.
A large industrial development, labelled Works, is present adjacent to the north of the Proposed Development Site including an associated rail track, which is both immediately adjacent and also encroaches the northern section of the Proposed Development Site.
Three small and two large circular features are present on land adjacent to the northwest of the Proposed Development Site (on land now occupied by Seabank 1 & 2), later labelled Seabank Gas Works.
The route of the Red Rhine has been straightened to pass along the north of the Seabank Gas Works.
Land adjacent to the east and south remains largely unchanged.
1970 1:1,250 The industrial site to the north comprises several large buildings, three rectangular tanks and at least six circular tanks.
Seabank Gas Works has been further developed and the works includes a series of at least ten banks of tanks and chimneys. The site adjacent to the northwest comprises at least six circular tanks, approximately 25m in diameter, which extend toward the north and west.
Land adjacent to the east and south remains largely unchanged.
1972 - 1977
1:2,500 A gas works comprising two circular tanks and a reservoir has been developed on land approximately 200m to the southeast of the Proposed Development Site.
1974 – 1975
1:10,000 The large industrial site to the north is labelled Severnside Works.
1999 1:10,000 The Seabank Gas Works on land adjacent to the west and northwest has been demolished.
Land adjacent to the south west is labelled disused landfill.
2006 1:10,000 The former Seabank Gas Works, adjacent to the west of the Proposed Development Site and immediately adjacent to the route of the electrical connection has been developed into Seabank power station (Gas fired).
The land adjacent to the north west remains undeveloped following the demolition of the large circular tanks.
Land to the use to the north, east and south remains largely unchanged except for the development of pylons which cross the Proposed Development Site but also extend to the north from the eastern section.
2013 1:10,000 The majority of the buildings of the Severnside Works adjacent to the north have been demolished.
The other surrounding areas remain unchanged.
13.4.13. The following paragraphs describe the current site condition and the
development of the surrounding areas based on a site visit undertaken during
November 2013, site mapping and also from the EA publication ‘Industry in
Avonmouth: A Guide to Pollution Management’. (Ref. 13-3). This publication
documents the activities of 12 potentially contaminating industries active in the
Seabank 3 PEI Report – Chapter 13 Ground Conditions
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Avonmouth area in 2002. Three of these are located within approximately 1km
of the Proposed Development Site; these are the Terra Nitrogen (UK) facility,
Seabank 1 & 2 and the Sevalco plant. As the Sevalco plant is located closer to
the cooling water pipeline route than the Proposed Development Site, it has
been discussed in detail in later sections in the chapter.
13.4.14. Terra Nitrogen (UK) was the name of the chemicals manufacturing company
which operated until approximately 2008 on the land adjacent to the north of
the Proposed Development Site. The site was taken over by Terra Nitrogen
(UK) from ICI Chemicals in 1998 and produced ammonia which was used to
produce nitric acid for the fertilizer industry.
13.4.15. Seabank 1 & 2 is located adjacent to the southwest of the Proposed
Development Site, although the electrical connection corridor and part of the
DCO Site crosses this facility. It began commercial operation in March 2000
and comprises gas and steam turbines which supply electricity to the national
grid.
13.4.16. Prior to the development of Seabank 1 & 2, the site comprised Seabank Gas
Works, which was operated as a gas-from-naphtha production facility between
1963 and the 1970s (Ref. 13-4). Prior to development of Seabank 1 & 2, site
investigation works were completed which identified contaminated ground
within the Seabank 1 & 2 footprint. Remediation works were completed, as
part of the redevelopment planning consent, to remove soil and groundwater
contaminated with metals, benzene, toluene, ethylbenzene and xylenes
(BTEX) and sulphide from the Seabank 1 & 2 site. Areas of soil contaminated
with tar / hydrocarbon were also reportedly removed. It is reported that risk
assessment works demonstrated that the remediation was successful. Small
parts of the Seabank 1 & 2 site were not remediated such as below electricity,
gas and water mains due to physical and safety constraints.
13.4.17. The EA publication ‘Industry in Avonmouth’ (Ref. 13-3) discusses the
processes of Britannia Zinc, which was a zinc smelting plant which operated at
Avonmouth for over 70 years before its closure in 2003. Although the plant
was located over 2.5km to the south of the Proposed Development Site, it has
been included here due to the potential for airborne metal contamination
affecting the soil.
13.4.18. Historical mapping identified the development of a gas works to the southeast
of the CCR Site during the early 1970s. This site is still operational as
Avonmouth LNG Storage Facility.
13.4.19. Given the low-lying nature of the area, the development of all the surrounding
industrial sites would have required the importation of fill material to raise site
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levels and provide suitable site surfaces, including the development of the rail
track in the centre of the southern boundary of the Proposed Development Site.
In addition, services, including water mains, gas mains and electricity pylons
have been developed across the Proposed Development Site. It is understood
that the gas mains were installed in drilled rather than trenched routes and
therefore it is unlikely that imported fill was used for these pipelines (Ref. 13-5).
13.4.20. During the site visit a significant amount of fly-tipped waste was noted in the
Proposed Development Site, predominately along the sides of the private track
running north/south through the centre of the Site (formerly part of Ableton
Lane). Pictures of the fly tipped waste are presented in Appendix I Part 2,
Volume II of this PEI report, and included materials such as baths, clothes,
demolition rubble, potential bound-asbestos roof panels, scrap metals, wood
and plastics.
Contamination
13.4.21. During the October / November 2013 GI, in general, no visual and/or olfactory
evidence of contamination of soils was identified. During logging of BH003, a
hydrocarbon type odour was reported between 4 and 6m depth. A total of 41
soil (including from where the odour was reported in BH003), 14 groundwater
samples and 4 surface water samples were scheduled for laboratory analysis.
13.4.22. An assessment of the results is given in the Phase II Report (Appendix I Part 4,
Volume II) which determined that no samples exceeded relevant Human Health
screening criteria. Minor exceedances of Controlled Waters screening criteria
were reported for metals arsenic, barium, copper, lead and selenium. These
are not considered likely to pose a significant risk to water quality. Alkaline
groundwater identified within the bedrock aquifer is considered likely to limit the
mobility of the metals species identified.
Recommendations include that construction and development workers should
be provided with appropriate personal protective equipment (PPE)
commensurate for earthworks. These should include, but are not limited to, the
use of gloves, overalls and eye protection particularly when in contact with
groundwater. Workers should also be made aware of the need for good
personal hygiene following contact with any soils during site works.
Geology
13.4.23. Geological mapping at 1:50,000 (Ref. 13-6) indicates the Proposed
Development Site and route of the electrical connection to be underlain by
Quaternary age Tidal Flat deposits consisting of normally consolidated soft silty
clay, with layers of sand, gravel and peat. The Envirocheck Report (Ref. 13-1)
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May 2014 Page 13-13
for the Proposed Development Site classifies the hazard potential for both high
compressibility ground and running sands within these deposits as moderate.
13.4.24. Underlying the superficial drift cover, the bedrock comprises Triassic age
Mercia Mudstone Group described as dominantly red, less commonly green-
grey, mudstones and subordinate siltstones. Typically halite-bearing units in
some basinal areas and thin beds of gypsum/anhydrite are present in the
Mercia Mudstone Group, however they are likely to be absent in this area of
the UK.
13.4.25. Historical borehole data available on the British Geological Survey (BGS)
website (Ref. 13-5) for boreholes drilled within 500m to the south and west
boundary of the Proposed Development Site indicates the thickness of drift
cover to be approximately 10 - 15m. The thickness of the Mercia Mudstone
Ground is identified within these boreholes as approximately 35 - 45m,
overlying Carboniferous Coal Measures strata at depths of approximately 40 -
50m below ground level (bgl). The Envirocheck Report (Ref. 13-1) lists the area
as a non-coal mining area of Great Britain.
13.4.26. Substantial thicknesses of Made Ground are not anticipated at the Proposed
Development Site due to low levels of previous development, as identified on
historical mapping provided within the Envirocheck Report (Ref. 13-1). The
mapping shows that railway sidings were present at the north eastern end of
the Proposed Development Site until they were later dismantled. This area,
together with the former rail tracks in the northern section of the site, is likely to
be underlain by minor thicknesses of Made Ground.
13.4.27. Table 13-6 details the ground stability hazard information contained within the
Envirocheck Report.
Table 13-6: Summary of Ground Stability Hazards for the Proposed Development
Site and Electrical Connection
Geological Potential Hazard Classification
Potential for collapsible ground stability hazards No hazard
Potential for compressible ground stability hazards Moderate
Potential for ground dissolution stability hazards No hazard
Potential for landslide ground stability hazards Very low
Potential for running sand ground stability hazards Moderate
Potential for shrinking or swelling clay ground stability hazards
Low
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13.4.28. Table 13-7 presents a summary of the geological strata encountered during the
GI.
Table 13-7: Summary of Site Geological Strata under the Proposed Development
Site
Strata Depth Range
(m bgl) Description
Topsoil 0 – 0.30 Firm dark brown slightly sandy clay with frequent rootlets. (Identified in BH004 only).
Tidal Flat Deposits 0.20 – 14.00
Firm, locally soft, fissured brown mottled grey silty clay. Occasional fragments of partially decomposed plant material and occasional PEAT.
Weathered Mercia Mudstone Group
9.00 – 17.50 Very stiff fissured dark reddish brown grey silty clay.
Mercia Mudstone Group
11.95 – base not proven
Extremely weak dark reddish brown mudstone interbedded with extremely weak to weak light greenish grey sandstone.
13.4.29. During the October / November 2013 GI, the GI contractors noted that running
sands had been identified at 5.10 to 8.60m bgl within the Tidal Deposits within
BH006. The occurrence of running sands was not widespread or consistent
within all boreholes.
Hydrogeology
13.4.30. The following EA hydrogeological classifications have been obtained for the
Proposed Development Site and the part of the Other DCO Land proposed for
the electrical connection, based on data included within the Envirocheck
Report:
• The superficial deposits likely to be encountered onsite are classified as
Unproductive strata;
• The Mercia Mudstone Group bedrock underlying the Site is classified as
Secondary B aquifer. Secondary B aquifers are defined as
‘predominantly lower permeability layers which may store and yield
limited amounts of groundwater due to localised features such as
fissures, thin permeable horizons and weathering. These are generally
the water-bearing parts of the former non-aquifers’;
• Groundwater Vulnerability mapping identifies that the Site is located on
a Non-Aquifer of negligible permeability; and
• The Site is not located within a Groundwater Source Protection Zone.
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13.4.31. The Envirocheck Report does not identify any licensed groundwater
abstractions within 1km of the Proposed Development Site.
13.4.32. Groundwater was identified during drilling in all of the boreholes and was found
to be shallow, with initial strikes between 1 and 3m depth within the Tidal Flat
Deposits. In addition, a second strike was recorded from a gravel layer at
approximately 12m depth in BH001. As water was added during coring, it was
difficult to assess the strikes within the bedrock during drilling although several
thick sections of sandstone were identified within the mudstone. These were
screened and found to be water bearing.
13.4.33. Four wells had installations in the Tidal Flat Deposits (BH001- gravel section,
BH003, BH005 and BH006) and three within the bedrock (BH002, BH004 and
BH007).
13.4.34. Following the intrusive investigation and site levelling, two groundwater
monitoring rounds were carried out. The average depth to groundwater from
both rounds of the wells installed in the Tidal Flat Deposits was 2.21m bgl
(4.36m AOD) and 2.23m bgl (4.39m AOD) for those installed in the bedrock.
In-situ parameter testing of the groundwater was completed during purging of
the boreholes and prior to groundwater sampling. The full results are recorded
in Table A of the Phase II Report (Appendix I Part 4, Volume II of this PEI
Report).
13.4.35. The depth to groundwater has been used to infer the groundwater flow
direction and gradient for the Tidal Flat Deposits and the bedrock. Both strata
indicate a flow direction toward the north at a gradient of 0.08m (Tidal Flat
Deposits) and 0.08m (Bedrock). A groundwater contour plan is presented as
Figure 1 of the Phase II Report (Appendix I Part 4, Volume II of this PEI
Report).
Hydrology
13.4.36. The Severn Estuary is located approximately 0.5km to the northwest of the
Proposed Development Site. The Proposed Development Site itself is
predominantly flat and low-lying and poorly drained with frequent areas of
standing surface water and marshland. The land at the southern end of the
Proposed Development Site is identified on both recent and historical mapping
as Crook’s Marsh. Flood maps contained within the Envirocheck Report
indicate the Proposed Development Site to be susceptible to flooding from
rivers or sea in the absence of any defences (Flood Zone 3).
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13.4.37. There are no recorded licensed and active surface water abstractions within
1km of the Proposed Development Site and the EA records no surface water
quality data for water bodies within 1km.
13.4.38. The Proposed Development Site is drained by several channels (minor rhines)
and a major channel (the Red Rhine) running from southeast to northwest
through the centre of the Proposed Development Site, which outfalls into the
Severn Estuary at New Pill Gout. It is understood that along with several of the
minor rhines, the Red Rhine is to be diverted to the northern boundary of the
Proposed Development Site by a third party, Severnside Distribution Land Ltd,
in advance of the Proposed Development. This diversion has therefore been
assumed as part of a future baseline for the Proposed Development.
13.4.39. Following the installation of monitoring wells in October / November 2013,
groundwater level recording pressure transducers were installed into three of
the ground monitoring wells for a 24 hour period to ascertain whether the
Proposed Development Site groundwater was tidally influenced. The data
obtained from the pressure transducers during the groundwater level
monitoring did not identify a tidal influence on the site groundwater.
Waste Facilities and Pollution Incidents
13.4.40. The Envirocheck Report lists waste facilities and those located within 1km of
the Proposed Development Site are summarised in Table 13-A in Appendix I
Part 1, Volume II of this PEI Report. One is considered to pose a potential
contamination risk to the site which is Crook’s Marsh Farm which was
operational between 1977 and 1979 located adjacent to the south west of the
Proposed Development Site and 20m southeast of the proposed electrical
connection route.
13.4.41. The Envirocheck Report and the EA Website, What’s in My Backyard feature
(Ref. 13-7), has been used to identify potentially contaminative pollution
incidents within 1km of the Proposed Development Site and electrical
connection. Two were identified within the vicinity of the Proposed
Development Site, both greater than 400m from the site and the details are
summarised in Table 13-B Appendix I Part 1, Volume II of this PEI Report.
Unexploded Ordnance
13.4.42. Due to the strategically important location of the Proposed Development Site,
in relation to Avonmouth Docks and the industrial complex, it is possible that
unexploded ordnance (UXO) exists at the Proposed Development Site.
13.4.43. The geophysical surveys used to assess the potential for UXO at the Proposed
Development Site were presented in ‘Report 3989 Geophysical Survey Report:
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May 2014 Page 13-17
UXO Scanning, July 2013’ (Ref. 13-8). This report presents only information
on the location and strength of the anomaly which reflects the distribution of
magnetic sources within the shallow sub-surface and in most cases is
associated with ferrous material/objects. A definitive interpretation of the
anomalies was not included; however possible sources were identified as
discarded debris/objects, buried features/structures, and potentially certain
types of UXO (those that contain sufficient magnetic material to be detected).
A number of anomalies were detected, with interference from known buried
services such as pipelines also identified.
13.4.44. As described in the Chapter 15: Archaeology and Cultural Heritage, evidence
of aerial defence structures has been identified near the Proposed
Development Site. This provides further evidence that the area was considered
a potential target for bombing.
Ground Gas
13.4.45. Hazardous ground gases can be derived from both natural strata and man-
made ground conditions. Natural strata which produce hazardous ground
gases typically include organic rich substrates such as alluvium and peats, as
respiratory breakdown of the organic compounds releases carbon dioxide and
methane.
13.4.46. The geology of the Proposed Development Site and proposed electrical
connection corridor is understood to comprise Tidal Flat deposits. These
deposits may contain peat layers and fragments of partially decomposed plant
material. Hence there is a potential for ground gas generation associated with
these natural strata.
13.4.47. Hazardous ground gases can also be released from organic rich fill material
within Made Ground. Given the site history and borehole logs, there is not
considered to be a significant amount of Made Ground at the Proposed
Development Site. There is however a former landfill adjacent to the south of
the Proposed Development Site and to the east of the proposed electrical
connection corridor, which has the potential to release ground gases. During
December 2006 ground gas monitoring was undertaken from boreholes in this
landfill site by third party (Ref. 13-9) and encountered methane concentrations
of up to 97.7%. The Phase II Report (Appendix I Part 4, Volume II of this PEI
Report) notes that consideration should be given to the prevention of a gas
migration pathway being created through any placed fill material if the site is
raised.
13.4.48. Information from the Envirocheck Report (Ref. 13-1) indicates that the
Proposed Development Site and the electrical connection corridor are located
Seabank 3 PEI Report – Chapter 13 Ground Conditions
May 2014 Page 13-18
in an area where there is no risk from radon. Guidance on protective measures
for new buildings (Ref. 13-10) shows that the Proposed Development Site is
located in an area where no protective measures are required.
13.4.49. During the October/November GI, each of the seven boreholes was installed
with a ground gas monitoring well. During the monitoring (undertaken on 19
and 20 November 2013) each gas well was monitored for volatile organic
compounds (VOCs) and landfill gases, and the findings are summarised as
follows;
• No detectable concentrations of methane were identified;
• VOC levels were very low (less than 0.2 parts per million (ppm));
• The maximum concentration of carbon dioxide was 2.1%;
• The maximum carbon dioxide concentration (BH002) corresponded to a
depleted concentration of oxygen (12.3%);
• The flow rate was recorded as a negative value in all locations with a
maximum negative of 4.3 litres per hour; and
• The atmospheric pressure recorded during the two day monitoring
event fell from 1018 milibars (mbars) on the first day to 999mbars on
the second.
13.4.50. An assessment of this data is provided in the Phase II report (Appendix I Part
4, Volume II of this PEI Report) which concluded that the risk from ground gas
was very low, although this should be verified following further gas monitoring
rounds.
The Proposed Cooling Water Pipeline Corridor
13.4.51. The proposed cooling water pipeline corridor is approximately 3.5km long and
30m wide that extends from Seabank 1 & 2 to the Bristol WWTW, as illustrated
in Figure 13-1 (Volume III of this PEI Report). The routing of this corridor has
been assessed as part of this PEI Report.
13.4.52. The cooling water pipeline corridor will pass through predominantly flat land
with only minor changes in elevation. OS maps indicate that the ground level is
at an elevation of approximately 6m AOD.
13.4.53. A site visit for the proposed corridor was conducted by URS on the 18
November 2013, during which observations were noted on land use , potential
contaminative sources along the route, indications of contamination (e.g.
distressed vegetation or discolouration/sheens on surface waters), and
indications of ground instability.
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May 2014 Page 13-19
13.4.54. Land uses within the proposed cooling water pipeline corridor are
predominantly agricultural and amenity based (including substantial stretches
of cycle pathways). Land uses directly adjacent to parts of the corridor
commonly include industrial or commercial usage. These land uses are
discussed in more detail below
13.4.55. Two sections of the cooling water pipeline were found to be inaccessible at the
time of the site visit: a short section (approximately 280m long) to the
southwest of the existing railway line and the short section within the Bristol
WWTW.
13.4.56. The proposed cooling water pipeline route was noted to cross a number of
shallow streams/rhines. Additional shallow streams or ditches were observed
close to the route. Where it was possible to observe these, no indications of
contamination were noted, with the exception of some discolouration limited to
a pipe discharging to a Stuphill Rhine. A shallow ditch containing water to the
immediate southwest of the current railway line (and to the immediate
northeast of the cooling water pipeline) had a sheen on it. Further observation
indicated this to be an organic derived platy sheen rather than a petroleum-
based mobile sheen.
13.4.57. Two areas of fly-tipping were observed, one alongside Chittening Road, the
other adjacent to the railway line. Only minor amounts of waste were observed
during the site visit (generally plastics including buckets).
13.4.58. No indications of ground instability were observed along the cooling water
pipeline corridor, which is to be expected since it is predominantly flat. It is
noted that given the changes in site history, some areas of infilling are
anticipated.
Site History and Contaminated Land Potential
13.4.59. The Envirocheck Report and site walkover were used to assess the history of
the cooling water pipeline corridor and the surrounding area. Table 13-C and
Table 13-D in Appendix I Part 1, Volume II of this PEI Report outline the history
of the proposed cooling water pipeline corridor and surrounding area and
further information about surrounding industrial uses is included.
13.4.60. In addition, the following land uses were noted during the site walkover:
• An aggregates facility was noted adjacent to the cooling water pipeline
approximately 300m south of Seabank 1 & 2. This is not shown on
maps therefore is considered to be relatively new. Heavy Plant was
observed working at this facility and therefore it is anticipated that the
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May 2014 Page 13-20
site includes fuel storage, however this was not observable from the
pipeline route;
• A site adjacent to the aggregates facility could not be fully observed,
however heavy plant was observed working in this site and a solvent
type odour was noted during the site visit adjacent to this site. It is
therefore possible that some usage or storage of chemicals occurs at
this site; and
• A number of wind turbines were observed close to the cooling water
pipeline. It is anticipated that utilities such as a transformer and cabling
will be associated with these structures; however the potential for
contamination is considered to be low.
13.4.61. The cooling water pipeline will connect to the Proposed Development Site via
Seabank 1 & 2. To avoid repetition, see section 13.4.13 to 13.4.20 for
discussion of the Seabank 1 & 2 site and immediate surroundings.
Geology
13.4.62. The BGS website / online borehole viewer (Ref. 13-7) and the Envirocheck
data sheet were used to assess the likely nature of the geological sequence
beneath the cooling water pipeline route. These resources indicate that the
following material is present:
• Historically the majority of the proposed cooling water pipeline is
located on land reclaimed from the Severn Estuary. Made Ground is
likely to be present in those areas where previous development has
taken place. Along the route of the cooling water pipeline several
sections comprise previously developed land and as such are likely to
include Made Ground. The locations of previously developed sections
are discussed in the site walkover section;
• The superficial geology below the cooling water pipeline consists of
Tidal Flat Deposits, which comprise consolidated soft silty clay of the
Holocene epoch; and
• The bedrock sequence underlying the cooling water pipeline is
indicated to comprise Mudstone of the Mercia Mudstone Group,
consisting of dominantly red, less commonly green-grey, mudstones
and subordinate siltstones with thick halite-bearing units in some
basinal areas. Thin beds of gypsum/anhydrite are widespread;
sandstones are also present.
13.4.63. Publicly available borehole records were accessed via the BGS online borehole
viewer. Three boreholes were assessed:
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1. Reference ST58SW124: located 600m from Seabank 1 & 2;
2. Reference ST58SW8 located on the route of the cooling water pipeline
1.24km along the pipeline route, measured from Seabank 1 & 2; and,
3. Reference ST58SW122 located 2,620m along the cooling water
pipeline and 190m to the west.
13.4.64. The available logs indicate the superficial deposits in the vicinity of the cooling
water pipeline largely comprise interbedded mudstone, sandstone and
siltstone. These deposits are recorded on the borehole logs as ‘drift’. Red and
green marl, part of the Keuper series (now part of the Mercia Mudstone Group)
was encountered between depths of approximately 18m and 55m bgl. Below
this, Upper Coal Measures mudstones of the Carboniferous Supra Pennant
Group are found to 142 m bgl.
Hydrogeology
13.4.65. As indicated on borehole log ST58SW122, water was encountered between
30.50m and 32.00m bgl in the Mercia Mudstone group unit. The resting water
level was recorded at 9.14m bgl. No resting water level was provided in the
other logs viewed.
13.4.66. The Tidal Flat Deposits in the area of the cooling water pipeline corridor, as
shown on mapping presented within the Envirocheck Report for the Proposed
Development Site, are defined as unproductive strata. Unproductive strata are
‘rock layers or drift deposits with low permeability that have negligible
significance for water supply or river base flow’.
13.4.67. The mudstone bedrock underlying the cooling water pipeline site is classed as
a Secondary B aquifer.
13.4.68. The area surrounding the cooling water pipeline has a groundwater
vulnerability zone classification of ‘non aquifer (negligibly permeable)’.
13.4.69. The cooling water pipeline corridor is not situated on any groundwater source
protection zones, as designated by the EA. The Envirocheck Report shows
three licensed goundwater abstractions within 1km of the proposed cooling
water pipeline corridor, all of which are at the Rhodia UK Limited/ Rhodia
Organique Fine Limited site, which has since ceased operation.
Hydrology
13.4.70. A number of surface waters are present around the proposed cooling water
pipeline corridor, some of which cross the route. These are generally shallow
streams, or rhines and include ‘Stuppill Rhine’, and ‘Salt Rhine’ located south
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May 2014 Page 13-22
of the railway crossing, and one named ‘Mere Bank Rhine’ near the Bristol
WWTW. All local streams are assumed to drain to the River Severn Estuary.
13.4.71. The Severn Estuary is the largest surface water feature in the vicinity of the
cooling water pipeline, 550m to the west.
13.4.72. South of the railway where the cooling water pipeline is likely to cross, there
are four ponds. The closest pond is approximately 10m from the cooling water
pipeline. These could not be viewed during the site visit due to access
restrictions in force at the time.
13.4.73. Near the Bristol WWTW, approximately 25m to the west of the cooling water
pipeline, there are 3 reservoirs.
13.4.74. There are no recorded licensed and active surface water abstractions within
1km of the water cooling pipeline and the EA records no surface water quality
data for water bodies within 1km.
13.4.75. Further information on the hydrological setting is provided in Chapter 14: Flood
Risk, Hydrology and Water Resources.
Ground Stability
13.4.76. Table 13-8 details the ground stability hazard information contained within the
Envirocheck Report.
Table 13-8: Summary of Ground Stability Hazards within the Cooling Water
Pipeline Corridor
Geological Potential Hazard Classification
Potential for collapsible ground stability hazards No hazard
Potential for compressible ground stability hazards Very low - moderate
Potential for ground dissolution stability hazards No hazard
Potential for landslide ground stability hazards Very low
Potential for running sand ground stability hazards Very low - moderate
Potential for shrinking or swelling clay ground stability hazards
Low
Waste Facilities and Pollution Incidents
13.4.77. A number of landfills and waste management facilities are reported within 1km
of the pipeline, the closest being 65m away, and these have been summarised
in Tables 13-F, 13-G and 13-H in Appendix I Part 1, Volume II of this PEI
Report.
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13.4.78. The Envirocheck Report has been used to identify potentially contaminative
pollution incidents in the area of the proposed cooling water pipeline corridor
and these have been summarised in Table 13-I in Appendix I Part 1, Volume II
of this PEI Report. Note that incidents considered more relevant to the
Proposed Development Site are included in the appropriate section above. One
incident was recorded within 10m of the proposed cooling water pipeline
corridor when a significant impact to water and land from oils and fuels was
registered in February 2008.
Unexploded Ordnance
13.4.79. As for the Proposed Development Site as described above, due to the
strategically important Avonmouth Docks and industrial areas, it is possible that
UXO exists along the cooling water pipeline. As described in the Chapter 15:
Archaeology and Cultural Heritage, evidence of aerial defence structures has
been identified in the area. This provides further evidence that the area was a
target for bombing.
13.4.80. In addition, due to the proximity of the cooling water pipeline to the former
munitions factory and shell filling facility (potentially immediately adjacent within
the Chittening Industrial Estate, as described in Appendix I Part 1, Volume II of
this PEI Report, it is possible that ordnance remains in the ground from those
activities. As described above, a suspected mustard gas shell was uncovered
in 2012 during groundworks in the former Britannia Zinc smelting works
(approximately 250m southwest of the proposed cooling water pipeline
corridor). Storage magazines are labelled in fields close to the cooling water
pipeline on an inter-war aerial photograph.
13.4.81. The possibility of encountering UXO along the cooling water pipeline will be
considered as part of the construction management plan that will be prepared.
Ground Gas
13.4.82. As outlined above, hazardous ground gases can be derived from both natural
strata and man-made ground conditions.
13.4.83. Hazardous ground gases can also be released from organic rich fill material.
Given the industrial history of the cooling water pipeline route, including current
and former landfills, there is considered to be a potential for the release of
hazardous ground gases.
13.4.84. As outlined above, mapping indicates that the Proposed Development Site and
the proposed route of the cooling water pipeline are located in an area where
there is no risk from radon.
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Preliminary Conceptual Site Model
13.4.85. The above baseline data regarding the Proposed Development Site and
proposed electrical connection corridor and proposed cooling water pipeline
corridor has been used to prepare a preliminary Conceptual Site Model (CSM)
to identify potential source-pathway-receptor pollution linkages.
Sources
13.4.86. The Proposed Development Site is believed to have undergone little previous
development as and such potential contamination sources are from the existing
railway, the area of historical farm buildings, the existing track, fly tipping and
surrounding land uses.
13.4.87. The proposed cooling water pipeline corridor passes through areas with a
variety of previous site uses and as such the potential contamination sources
are potentially numerous and variable along the extent of the corridor.
13.4.88. Ground gases may be released from underlying geology including the natural
organic-rich strata and Made Ground or filled areas.
Receptors
13.4.89. The potential contamination receptors are considered to include:
• Future site users i.e. staff and visitors of the proposed development;
• Construction and maintenance workers;
• Adjacent site users;
• Rhines; and
• The Severn Estuary.
Pathways
13.4.90. The potential pathways between the sources and receptors are considered to
include:
• Human ingestion of soil;
• Human dermal contact with soil
• Human inhalation of volatile contaminants via volatilisation from soil
and/or groundwater and subsequent vapour intrusion in to buildings or
dispersion into outdoor air;
• Human inhalation of soil derived dust via surface dust release outdoors
and/or tracked back soil into buildings;
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• Leaching from contaminated soils to groundwater and subsequent
migration within groundwater to and inflow into identified surface
waters;
• Migration of contaminated groundwater to and inflow into identified
surface waters; and
• Migration of ground gases into buildings.
Summary of Baseline Information
13.4.91. Table 13-9 provides a summary of the site sensitivity for the DCO Site based
on the information detailed above.
Table 13-9: Proposed Development Site Environmental Sensitivity
Parameter Receptor Sensitivity Reasoning
Groundwater Low Tidal flat deposits are classified as unproductive strata whilst the underlying mudstone bedrock is classified as Secondary B Aquifer. The Proposed Development Site is not situated on any groundwater source protection zones. Licensed groundwater abstractions in the area are limited to industrial usage with no potable water abstractions identified.
Surface Water High The Severn Estuary is approximately 400m from the Proposed Development Site. The Proposed Development Site is crossed by several small streams, or rhines, including the Red Rhine (which will require diversion works). This network of rhines in the area discharges to the Severn Estuary. No recorded licensed and active surface water abstractions were identified within 1km of the Site.
Moderate Following the diversion of the Red Rhine to the northern perimeter of the Proposed Development Site, the sensitivity to potential effects is considered to be reduced (due to the increase in distance from the site activities).
Environmentally Sensitive Receptors
Low (Moderate for the Severn Estuary)
The Severn Estuary is designated as a SAC, SPA, Ramsar site and SSSI and is approximately 400m from the Site.
An area of Adopted Green Belt is present approximately 550m east of the Proposed Site.
Human Receptors
Low The DCO Site is in a commercial area and the closest residential properties are approximately 1.1km south east of the Site.
High Groundworks will be required during construction and as such the workforce may be in direct contact with soil and groundwater. During the operational phase there should be no requirement for the workforce to be in direct contact with soil or groundwater.
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13.4.92. Table 13-J and 13-K in Appendix I Part 1, Volume II of this PEI Report present
a list of potential contamination present on the Proposed Development Site and
associated infrastructure, based on the areas of development and historic land
uses identified. These are based on guidance in the NHBC/EA document
Guidance for the Safe Development of Housing on Land affected by
Contamination (Ref. 13-11).
13.5. Development Design and Impact Avoidance
13.5.1. A number of impact avoidance measures have been incorporated into the
design. These measures have therefore been taken into account during the
assessment presented in this chapter.
13.5.2. The Proposed Development incorporates a minimum 8m buffer strip alongside
the southern side of the realigned Red Rhine for access by the LSIDB. This
should inherently reduce pollution risks during construction, once the
Generating Station Site has been raised, by creating a natural setback from
this watercourse.
13.5.3. The Generating Station Site will be raised to a maximum 8.5m AOD, which
equates to an average 2.2m above current ground levels for this part of the
Site. This material will be tested prior to accepting it onsite and will minimise
the need for excavation of existing soils onsite. Where possible, any excess
material from the installation of the cooling water pipeline will be used onsite as
part of the land raising.
13.5.4. Chapter 5: Enabling Works and Construction provides an overview for the
methods of installation for the proposed cooling water pipeline. A number of
potential risks associated with diverting the main gas pipeline beneath the
Proposed Development Site and crossing the Government Pipeline and
Storage System (GPSS) oil pipelines have been mitigated through design and
should pose negligible risks to this 3rd party infrastructure and the environment.
These are therefore not discussed further.
13.5.5. Additional mitigation measures and industry-standard control measures are
discussed in Section 13.6 to minimise potential effects on ground conditions.
13.6. Potential Effects and Mitigation Measures
Site Preparation and Construction Phase
13.6.1. During the construction phase of the Proposed Development and associated
infrastructure there are a number of potential effects on the geology,
hydrogeology or land that may have a direct or indirect effect on sensitive
receptors.
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May 2014 Page 13-27
13.6.2. As detailed in Chapter 5: Enabling Works and Construction, it will be a
Requirement that the Principal Contractor will prepare a site wide CEMP for the
development. This document will set out the management, monitoring, auditing
and training procedures that will be in place to ensure compliance with the
applicable regulations.
13.6.3. All construction works undertaken will be carried out in accordance with
procedures and mitigation measures outlined in the CEMP, which will be
produced by the selected contractor before the commencement of any works.
13.6.4. The principal effects and the required mitigation measures that will be
embedded within the design and management of the Proposed Development
are discussed in the following sections. The potential sources, pathways and
receptors for the site preparation and the construction phase of the Proposed
Development and associated infrastructure are presented in Table 13-10.
Table 13-10: Potential Sources, Pathways and Receptors for Consideration
during the Site Preparation and Construction Phases
Category Description
Sources Soil and groundwater impacted from general construction activities/site preparation (the Proposed Development Site and the cooling water pipeline)
New contamination pathways created by the construction of piled foundations (the Proposed Development Site) / below ground structures (the Proposed Development Site and the cooling water pipeline)
Localised soil and groundwater contamination in Made Ground and underlying strata (as identified in onsite contamination source tables)
Off-site soil and groundwater contamination migrating on-site
Pathways To Human health Receptors:
• Vapours – Migration of vapours through made ground into above ground buildings (temporary construction buildings or cabins).
• Vapours – Migration of vapours through made ground into above ground buildings (permanent buildings – the Proposed Development Site only, not the cooling water pipeline)
• Particulate – Ingestion, inhalation and dermal contact with soil particulates.
• Permeation – Migration of contaminant substances through plastic potable water supply pipes (the Proposed Development Site only – not the cooling water pipeline).
• Gas – Migration of ground gas through made ground into above ground buildings (temporary construction buildings or cabins).
• Gas – Migration of ground gas through made ground into above ground buildings (permanent buildings – the Proposed Development Site only, not the cooling water pipeline)
• Human exposure to soils during construction and excavation works and movement of soils offsite.
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Category Description
To Controlled Waters Receptors:
• Leaching – Migration of contaminant substances from soils into perched water and groundwater,
• Migration of affected perched water and groundwater, if present, to surface water.
• Historical, current and proposed service routes which may act as preferential pathways for contaminant migration.
To Environmentally Sensitive Areas:
• Leaching – Migration of contaminant substances to surface waters of the Severn Estuary (designated under various schemes including SAC, SPA, Ramsar and SSSI, and)
• Leaching – Migration of contaminant substances to soil and groundwater of Adopted Green Belt.
Receptors Human Health receptors:
• Workers onsite during construction works.
• Workers onsite once the development has been built (the Proposed Development Site only, not the cooling water pipeline).
• The general public and staff visiting site once it has been developed (both the Proposed Development Site and the cooling water pipeline)
• Nearby workers within local commercial properties.
Controlled Waters Receptors:
• Various surface water ponds and drains / rhines.
• Severn Estuary.
Environmentally Sensitive Areas:
• Surface waters and inter-tidal mud flats of the Severn Estuary
Soil and Groundwater Contamination
13.6.5. Based on the results of the baseline assessment that has been completed for
this PEI Report, it is considered that the potential magnitude of the change
brought about by construction will be Medium. This is based on the risks to
surface water (high environmental sensitivity) rather than groundwater (low
environmental sensitivity) as it is feasible that existing soil and groundwater
contamination could enter the surface waters either through mobilisation from
soil and groundwater or through direct loss into to surface waters that are
present within the Proposed Development and associated infrastructure.
13.6.6. Materials management procedures such as the creation of bunded storage
areas and use of water storage lagoons or water treatment plants, as
appropriate, will be used to minimise the potential for excavated soil or pumped
groundwater to enter the surface waters. A Materials Management Plan
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(MMP) and CEMP will be a requirement of the Proposed Development and will
develop the mitigation measures in the final ES further. The predicted effect of
direct loss to surface waters is therefore considered to be of negligible
significance.
13.6.7. With regard the potential for the works to mobilise contaminants through soil
and water to the surface waters, or to groundwater it is considered that the
predicted effect of the development construction on the ground conditions will
be negligible in the Proposed Development Site as no significant
contamination was identified during the GI.
13.6.8. Intrusive investigation has not yet been undertaken for the proposed cooling
water pipeline corridor; it is anticipated this would be undertaken post-consent,
prior to the installation of the pipeline and any contamination would be
remediated. These further investigation and assessment works will be
undertaken in accordance with the requirements of CLR11, GPLC1-3, GP3 and
any specific Requirements agreed as part of the DCO prior to site construction
works commencing.
13.6.9. Contamination within soils has the potential to adversely affect the health of
construction workers; this is considered to have the ability to lead to a Medium
magnitude of change without proper mitigation. Health and Safety mitigation
measures, appropriate to the chemical composition of the ground (and potential
groundwater), will be evaluated and implemented to protect the construction
workers’ health. As such, any existing contamination is expected to have a
negligible significance to construction workers provided that the appropriate
mitigation measures are adopted such as the appropriate use of PPE, hygiene
practices and decontamination units, if required. The clear exception to this
would be the potential presence of UXO and / or chemical warfare (CW) agents
(e.g. mustard gas) which are discussed in more detail in the UXO section
below.
13.6.10. Land raising works will be an integral part of the Proposed Development Site
construction to achieve the proposed Site formation levels to mitigate potential
flood risk as outlined in Chapter 14: Flood Risk, Hydrology and Water
Resources. The potential magnitude of change is considered to be Medium on
surface waters without adequate mitigation, which is discussed below.
13.6.11. Earthworks will be carried out with due regard to the current regulatory regime
for waste management. Material arriving on-site will be tested at an
appropriate frequency (depending on its source) to confirm that it is suitable for
use. Bulk materials such as topsoil and fill material will be stored in designated
areas away from watercourses and covered to prevent erosion. The 8m
maintenance access strip proposed alongside the realigned Red Rhine will
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increase the distance of stockpiles from the main identified watercourse.
Specific guidance in dealing with silt arising from construction activities is
contained within PPG5, which will be taken into account within a CEMP.
13.6.12. Site materials will be reused to level the Proposed Development Site where
possible; for example any surplus soil from the trench for the proposed cooling
water pipeline could be used as part of the land raising for the Proposed
Development Site. The procedure for managing the re-use of soils will be
documented in a MMP which will be produced in general accordance with
CLAIRE Code of Practice ‘The Definition of Waste: Development Industry Code
of Practice’, 2011 (CLAIRE, 2011).
13.6.13. Where surplus soil requires disposal, i.e. it is not deemed suitable for re-use, it
will be disposed of to an appropriate, licensed landfill facility, in accordance
with current Duty of Care responsibilities and other statutory requirements. As
required by the Landfill Directive, inert, non-hazardous and hazardous waste
will require pre-treatment prior to disposal.
13.6.14. Prior to disposal, soil will need to be characterised following the methodology
described in the EA publications ‘Framework for the Classification of
Contaminated Soils in Hazardous Wastes’, version 1 (Ref. 13-12) and
‘Guidelines on sampling and testing of wastes to meet landfill waste
acceptance procedures’ version 1. (Ref. 13-13).
13.6.15. Taking these measures into account, the predicted effect on surface water is
considered to be negligible.
Storage of Potentially Contaminating Materials and Accidental Spillage
13.6.16. During construction there is potential for accidental spillage or vandalism to
result in a release of contaminants from vehicles, refuelling areas, storage
tanks, plant and machinery. Contaminants released could be chemicals, oils,
hydrocarbons or construction materials, and have the potential to enter the
sub-surface. This could detrimentally affect soil and groundwater quality. This
in turn could subsequently affect the sensitive surface water receptors
identified at the DCO Site.
13.6.17. The magnitude of the change to the land due to accidental spillage of fuels or
other contaminants from construction activities is dependent on the frequency
and size of the spillage. However, a spillage would be likely to present a
Medium magnitude of change on identified receptors during the construction
phase prior to mitigation.
13.6.18. To minimise the risk of accidental fuel and chemical spills, the following
mitigation measures will be employed:
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• Oils and hydrocarbons will be stored in designated locations with
specific measures to prevent leakage and release of their contents,
including the siting of storage areas away from surface water drains, on
an impermeable base with an impermeable bund that has no outflow
and of adequate capacity to contain 110% of the contents;
• Wherever possible, stationary construction plant and machinery will
have drip trays beneath oil tanks/engines/gearboxes/hydraulics, which
will be checked and emptied regularly via a licensed waste disposal
operator;
• Installation of oil interceptors at the point where site surface water runoff
enters the Red Rhine, as appropriate;
• An emergency spillage action plan will be produced, which site staff will
be required to have read and understood. On-site provisions will be
made to contain a serious spill or leak through the use of spill kits,
booms, bunding and absorbent material; and
• All construction works will be carried out in accordance with site
specific method statements which will cover storage and use of
chemicals and fuels during construction. These will be in accordance
with regulatory guidance (e.g. EA pollution prevention guidelines) and
will be agreed in advance with the EA, SGC and BCC. It is proposed
that standard duties of care are employed with regard to delivery, use
and storage of potentially contaminating materials and liquids (bunded
storage platforms, control of substances hazardous to health (COSHH)
assessments and safety inductions etc.).
13.6.19. There will also be a minimum of a 2m buffer outside of the 8m easement along
the Red Rhine (10m in total) during construction to reduce pollution risks,
resulting in any chemicals or liquids being stored a minimum of 2m from the
edge of the (8m wide) maintenance strip. There will be no storage of bulk
materials or potential contaminants in this area.
13.6.20. It is anticipated that the implementation of the above, as well as a site specific
method statement and CEMP, will render the potential effects to be of
negligible significance.
Asbestos
13.6.21. Asbestos is a common contaminant within Made Ground fill materials, and was
included within the suite of ‘determinands’ measured during the GI for the
Proposed Development Site and will be considered during any investigation of
the proposed cooling water pipeline route. The GI soil analysis did not identify
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any asbestos containing materials (ACM), although given the widespread fly-
tipping present on the Development Site, it is possible that ACM are present.
The magnitude of change is considered to be Medium-High depending on the
level of asbestos present.
13.6.22. Should the presence of asbestos be identified in any pre-construction testing,
then appropriate measures will be implemented to mitigate the risks in
accordance with the Hazardous Waste Regulations (EA PPGs) and with
adherence to relevant Health and Safety guidelines. The predicted effects
following implementation of appropriate mitigation measures are considered to
be of negligible significance.
Disturbance of Dust and Silt
13.6.23. Dust and silt could resulting from soil disturbance during construction activities
may arise as a result of the movement of potentially contaminated soil by
construction machinery. This could result in an increase in suspended solids
i.e. the silting up of surface waters, or may have adverse effects on the health
of construction workers and the general public. The potential magnitude of
change is considered to be Medium.
13.6.24. Mitigation of potential dust effects that will be implemented are discussed in
further detail within Chapter 11: Air Quality.
Geotechnical Considerations
13.6.25. The required foundation design for the Proposed Development Site has not yet
been determined and will be chosen at the detailed design stage after receipt
of the DCO. Geo-environmental site investigation of the construction footprint
areas has been undertaken in order to establish the most appropriate
foundation design solution(s). At the time of writing this PEI Report, the
geotechnical data from this investigation is not yet available.
13.6.26. Depending on the final design, limited geo-technical testing may also be
required for the cooling water pipeline.
13.6.27. The requirements for a piled foundation solution will be dictated by the
observed ground conditions and the result of appropriate geotechnical testing
and design. Selection of a pile type / construction method will be based on
consideration of the technical requirements for supporting the building loads
and the potential for creating a preferential pathway for contaminant migration
through the underlying geological strata units. CFA piling is currently the
preferred piling method and is likely to be required for the turbine buildings,
HRSG buildings, and cooling water pump pits, although other structures such
as the peaking plant may also require piling.
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13.6.28. Construction of large structures over Made Ground and / or unconsolidated
superficial deposits has the potential to result in settlement and subsidence of
the ground over time. The magnitude of such a change is considered to be
High given the potential outcome of settlement and subsidence of the
development.
13.6.29. Appropriate foundations will be designed at the detailed design stage and
informed by the outcome of the on-going Phase 2 geotechnical intrusive
investigation at the Proposed Development Site. New buildings will be
constructed with suitably designed foundations to ensure that the long-term
settlement of the building will occur within acceptable limits. Through
implementation of appropriate foundation design and possible ground
improvement, residual effects associated with settlement and subsidence are
considered therefore considered to be of negligible significance.
13.6.30. Construction of deep piles or foundations has the potential to create
preferential pathways for contaminant migration. However, no significant
contamination was identified during the GI and the significance is therefore
considered to be negligible. Should currently unidentified contamination be
identified, and the creation of a pathway be plausible and lead to a complete
source-pathway-receptor linkage, then foundation design will be used to
minimise the potential for this to occur. This will be in accordance with the
requirements of the EA ‘Piling and Penetrative Ground Improvement Methods
on Land Affected by Contamination’ document (Ref: 13-15).
13.6.31. Aggressive ground conditions such as elevated sulphate concentrations and
low pH values in soil and groundwater have the potential to cause significant
degradation to sub-surface concrete structures. As above, the potential
magnitude of change is considered to be High, due to the potential outcomes
from loss of integrity of concrete foundations. With reference to the relevant
Building Research Establishment (BRE) guidance, the required composition of
concrete can be selected to reduce the effect on sub-surface building materials
to negligible.
Ground Gas
13.6.32. The magnitude of change with regards to ground gas is considered to be Low
given the short term nature of the construction works and therefore exposure to
the receptor (workers). The effect of ground gas at this stage is predicted as
being of negligible significance, on the basis that the construction of the
Proposed Development and cooling water pipeline is unlikely to exacerbate
ground gas conditions.
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May 2014 Page 13-34
13.6.33. It is however recognised that the presence of ground gas may pose restrictions
on the construction of the Proposed Development. It is unlikely to pose
restrictions on the construction of the cooling water pipeline given that no
permanent buildings are likely to be required. The magnitude of the change
from these restrictions is considered to be Low.
13.6.34. The GI included monitoring for the presence of ground gases and the
assessment identified a very low risk but recommended further monitoring to
confirm this although currently it is considered that the effect on the Proposed
Development Site is negligible. The potential for generation of ground gas
from Made Ground materials underlying the DCO Site represents a potential
long-term negligible to minor adverse effect to the health of site users and to
the development. This effect will be local, i.e. it will only be present within
buildings on site, however is likely to be permanent whilst the buildings remain.
13.6.35. In addition the radon risk has been assessed as low for the DCO Site.
Underground Structures
13.6.36. During the construction phase, there are a number of constraints relating to
existing operations and services in the vicinity of the DCO Site. The most
significant constraints are the existing high pressure gas mains and an oil
pipeline that cross the proposed cooling water pipeline route. There are also
overhead electricity cables and underground gas pipeline and water main that
cross the Proposed Development Site. Construction works around these
features will be undertaken in close consultation with the utility owners and
involving the input of specialist contractors as appropriate.
13.6.37. Underground obstructions such as existing service lines are known to be
present beneath points along the proposed route of the cooling water pipeline.
Of particular environmental significance is the presence of hydrocarbon
transfer pipes that cross the cooling water pipeline route. These are below
ground at the point at which they cross the cooling water pipeline. Accidental
disturbance of these structures (particularly where buried below ground) could
result in the loss of hydrocarbon product from these pipelines. BCC has
commented on the presence of these pipelines and has noted that specialist
contractors will be required for works in the pipeline vicinity. Consent from the
Crown is required prior to this work commencing.
13.6.38. On the basis of the sensitivity of surface water receptors and the presence of
the hydrocarbon pipelines, the potential magnitude of change is considered to
be High.
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13.6.39. Prior to the commencement of excavation works appropriate steps including a
detailed survey of the services locations and depths will be taken to ensure that
construction activities do not disturb any live services.
13.6.40. Assuming that service clearance procedures are followed and an appropriate
management procedure is developed and implemented by appropriate
specialist contractors, the effect on the various existing underground structures
is considered to be of negligible significance.
Unexploded Ordnance (UXO)
13.6.41. Encountering UXO during piling and excavation represents a potential major,
albeit unlikely, short-term adverse effect to the safety of construction workers.
A UXO study has been undertaken for the Proposed Development Site, and
may be a requirement for the proposed cooling water route after receipt of the
DCO, and prior to construction. Given the risks from both historical aerial
bombing and the former munitions factory, further assessment of the risks on
the cooling water pipeline route will be required after receipt of the DCO and
prior to construction. The magnitude of the change associated with
encountering UXO is considered to be High.
13.6.42. Commissioning of an UXO desk study report, prior to construction, will assess
the risk of encountering UXO on site and recommend any mitigation measures
required to render potentially adverse effects negligible. Such mitigation
measures may include:
• Explosive Ordnance Safety and Awareness Briefings for personnel
conducting intrusive works;
• Unexploded Ordnance Site Safety Instructions for site personnel;
• Presence of an Explosive Ordnance Disposal Engineer on site to
supervise open excavations; and
• Down-hole intrusive magnetometer surveys of all deep intrusive works
and target investigation of suspect anomalies.
13.6.43. The potential magnitude of the severity / harm is likely to be extremely high, but
the likelihood of occurrence is typically very low. The most applicable approach
to manage these potential risks is to further reduce the likelihood of occurrence
through appropriate investigation ahead of construction work. Following this
mitigation, such as the removal of identified UXO, where required, and taking
into account the low risk of occurrence, the significance of this effect is
considered to be negligible.
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Operational Phase
13.6.44. The assessment of land contamination in respect to new development is based
on a “suitable for use” approach. Any risk assessment, remediation and
verification works that are required will be agreed, implemented and validated
as part of the pre-construction and / or construction phase and as such any
issues will have been dealt with prior to the operational phase.
13.6.45. Operational phase effects associated with land contamination are limited to the
storage and use of potential contaminants on site, i.e. the potential for further
land contamination to occur through the operation of the development. The
sensitivity of the receptor will be lower for this phase, as it is understood that
the Red Rhine will have been diverted, and there will be no requirement for
works within the cooling water pipeline corridor. However given that bulk
chemical storage will occur on the Site (for the distillate storage and water
treatment plant for example), the potential magnitude of change is Medium.
13.6.46. The Proposed Development will use similar bulk materials to those already in
use at Seabank 1 & 2. The bulk chemical storage inventory for Seabank 1 & 2
(Ref. 12-16) indicates that bulk storage currently includes distillate, acids (e.g.
sulphuric acids), treatment chemicals (e.g. sodium chlorite, ammonia solution,
and hydrazine), chemical inhibitors (e.g. algaecide, antifoam etc.), and
hydrocarbons (e.g. lubricating oil, transformer oil).
13.6.47. Suitable mitigation measures will be taken to protect controlled waters from the
release of chemicals, distillate and oils in accordance with the requirements of
the Environmental Permit for the operational plant and EA guidance and best
practice. These measures will comprise the following:
• Fuels will be stored in tanks designed specifically for purpose, with
measures to prevent leakage and release of their contents, for example
siting of tanks and other oil storage away from surface water drains, on
an impermeable base with an impermeable bund that has no outflow
and is of adequate capacity to contain 110% of the contents;
• Installation of oil interceptors at the point where site surface water runoff
enters the Red Rhine;
• An emergency spillage action plan will be produced, which site staff will
be required to have read and understood. On-site provisions will be
made to contain a serious spill or leak; and
• Site security will be such to prevent vandalism and deliberate release of
contaminants to soil and groundwater.
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13.6.48. With the above mitigation measures in place the significance of this potential
effect is considered to be minor adverse as the operator of the plant has an
obligation under the Environmental Permit to prevent contamination of the site
during its operation and eventual decommissioning and closure.
13.6.49. The Proposed Development will require an Environmental Permit from the EA
for it to be able to operate. Regulation 12 of the Environmental Permitting
Regulations 2010 requires that “A person must not, except under and to the
extent authorised by an environmental permit; operate a regulated facility; or
cause or knowingly permit a water discharge activity or groundwater activity’”.
Management of operational phase risks will be undertaken and regulated under
the Environmental Permit. This will include appropriate storage, use and
disposal of hazardous materials used on the site.
13.6.50. The effects associated with the supply and discharge of cooling water is
considered in detail in Chapter 14: Flood Risk, Hydrology and Water
Resources. The cooling water supply will be treated a water treatment plant.
The magnitude of change associated with leakage from the proposed cooling
water pipeline is considered to be Medium, given that the water is designed
only to achieve the effluent discharge standards from Bristol WWTW. The
likelihood of such leakage however is considered to be low given that the
pipeline will be of a new construction and tested prior to use. Bearing this in
mind the operational phase land quality effects are therefore assessed as
negligible for the Proposed Development Site and the cooling water pipeline.
Decommissioning
13.6.51. Decommissioning of the Proposed Development Site and associated
infrastructure would require a MMP, method statements and a site closure
plan. These would be used to mitigate the risks of additional ground
contamination from the decommissioning phase. The risks associated with
spillages and contamination are considered similar to the construction phase,
although to a lesser extent and shorter in duration.
13.6.52. It is noted however that the main difference between construction and
decommissioning is the presence of process chemicals on site. It is feasible
that contamination could be released from the plant during
dismantling/demolition. The potential magnitude of change is therefore
considered to be high. All tanks will be drained of stored materials and plant
will be tested to ensure that there are no residual chemicals and it is clean prior
to dismantling. It is therefore considered that the significance of the effect is
likely to be negligible.
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13.6.53. In addition, in order to surrender the Environmental Permit, the permit holder is
required to provide sufficient evidence to the EA to demonstrate that the
operation of the permitted facility has not caused degradation of the soil or
groundwater conditions at the DCO Site. In the unlikely event that they have
caused degradation the operator would be required to remediate the land and
therefore mitigate any effect.
13.6.54. The risks associated with the decommissioning phase for ground conditions
are therefore considered to be negligible.
13.7. Residual Effects
13.7.1. The Proposed Development is proposed to be constructed on previously
undeveloped land, thus only surrounding land uses could have affected the
Proposed Development Site soil and groundwater quality. However, the
associated infrastructure (cooling water pipeline) is likely to encounter affected
land due to the historic land use.
13.7.2. A range of potential contaminants have been identified for the previous land
uses of the land through which the associated infrastructure is planned to be
routed. Standard mitigation measures of detailed site investigation, risk
assessment and remediation design and implementation will be employed
where required. This approach is consistent with EA / Defra Contaminated
Land Report 11: Model Procedures for the Management of Land
Contamination (Ref. 13-2).
13.7.3. Implementation of the proposed approach, described in section 13-6, will
mitigate land contamination risks during construction.
13.7.4. The Envirocheck Report identified moderate ground stability hazards including
compressible ground, and running sands and running sands were identified
during the October/November 2013 GI. Site specific information on ground
conditions for the Proposed Development Site will be considered when the
geotechnical information from the GI is assessed. This is anticipated to take
place following the submission of the DCO Application and will include
recommendations for foundation requirements based on the encountered
ground condition of the Proposed Development Site.
13.7.5. Although not expected, should piled foundations be required in any areas
where contamination is identified (such as due to fly tipping onsite), the piling
design will be subject to a Piling Risk Assessment following EA guidance (Ref.
13-15) post consent, and subsequent regulatory review and agreement.
13.7.6. Ground gas identified a very low risk to the Proposed Development Site.. In
addition, there is little potential for offsite migration onto the land through which
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the associated infrastructure is being routed, as this infrastructure does not
include enclosed building spaces, and therefore the effect is considered
negligible.
13.7.7. In summary, no significant effects on land quality are expected to occur
throughout the construction and operational phases, provided that standard
mitigation measures are applied as discussed above. Table 13-11 summarises
the residual effects on land quality and the hydrogeological regime.
Table 13-11: Summary of Residual Effects (post-mitigation)
Description Geographic Scale
Effect Significance
Reversible/Permanent
Construction Phase
Changes to concentrations and extent of soil and groundwater contamination
Local Negligible or Minor Beneficial
Permanent, provided remedial works are
designed appropriately.
Storage of Potentially Contaminating Materials and Accidental Spillage
- Negligible -
Asbestos - Negligible -
Disturbance of Dust and Silt - Negligible -
Geotechnical Considerations - Negligible -
Ground Gas Local Negligible Permanent, whilst buildings remain on
site.
Underground Structures - Negligible -
Unexploded Ordnance - Negligible -
Operational Phase
Storage of Potentially Contaminating Materials and Accidental Spillage
District level Minor Adverse Reversible through early detection and
remediation
Use of the cooling water pipeline - Negligible -
Decommissioning Phase
Release of potentially contaminating materials during dismantling of plant
- Negligible
Degradation of soil and groundwater conditions
- Negligible
13.8. Cumulative Effects
13.8.1. This section assesses the effect of the Proposed Development and associated
infrastructure in combination with the potential effects of other developments
proposed for the local area. Consented and proposed schemes within the
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area, which are considered sufficiently close to result in potential cumulative
effects with the Proposed Development, have been identified as outlined in
Chapter 7: Assessment Methodology. Identified schemes have been reviewed
in terms of both the construction and operational phase effects.
Construction Impacts
13.8.2. Table 13-12 details potential cumulative effects during the construction phase
of consented and proposed schemes in the local area which are sufficiently
close to either the Proposed Development Site or the proposed cooling water
pipeline corridor.
Table 13-12: Construction Phase Cumulative Issues
Cumulative Development (Applicant)
Potential issues to be considered
Avon Power Station (Scottish Power Generation Ltd)*
The Preliminary Environmental Assessment (Ref. 13-16) identified remediation work in 2010 which removed soils with elevated radiation levels. There is, however, likely to be affected soil remaining at the adjacent Avon Power Station site which may be disturbed during the construction phase. In addition, potential piling works would have the potential to create contamination pathways to groundwater and bring affected soil to the surface as arisings.
Re-Alignment of Approved Spine Road Access (Severnside Developments Land Ltd)
There is the potential for the construction works to disturb contaminated soil in the previously developed section of the site, in the vicinity of the former rail track. (Ref. 13-17)
Central Park (Severnside Distribution Land Ltd)
The land for Central Park is currently being raised to protect against flood risk and although there is a potential for impacted material to be imported to site it is considered that this would be controlled by the developer in liaison with SGC.
Bottom Ash Recovery Facility (SITA UK Limited)
During the construction phase, contaminated soils associated with previous land use as a gas storage facility and rail sidings of the former Severnside Works could be disturbed. Also, the construction of the rhine crossings and potential spillages and site run off could affect surface water quality. In addition piling works have the potential to create contamination pathways to groundwater and bring effected soil to the surface as arisings (Ref. 13-18).
W4B, Former Columbian Chemicals (Sevalco), Severn Road
Redevelopment of part of existing industrial site for a Bio-fuel, renewable energy plant together with ancillary access roads, parking facilities and landscaping. There is the potential for the construction works to disturb contaminated soil in the previously developed section of the site.
Sita/Cyclamax, Plot M2, Merebank Estate, Kingsweston Lane
The Bristol Resource Recovery Centre, currently under construction has the potential to disturb contaminated soil during construction and to release dust to air during the operational phase, although the latter should be controlled by the site’s environmental permit.
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Cumulative Development (Applicant)
Potential issues to be considered
Asda/Walmart, Former Rhodia Works, St. Andrews Road
During the redevelopment of the former chemical works, there is the potential for the construction works to disturb contaminated soil.
Biomass Plant (Helius Energy)
The biomass plant ES (Ref. 13-18) identified potential disturbance of the following hazards during the construction phase: contaminated Made Ground from historic coal storage and former railway and fuel storage use as well as unexploded ordnance.
Rockingham Park (Terramond Ltd)
The Design and Access Statement for this development (Ref. 13-19) discusses the heavy antiaircraft battery at Rockingham farm which was built to protect the strategically important docks at Avonmouth and the potential for Made Ground. It is therefore possible that unexploded ordnance and contaminated soils could be disturbed during the construction phase
Resource Recovery Centre (Viridor)
The ES Identified the following potential risks during the construction phase to groundwater quality;
• Accidental spillage of fuels and lubricants required over the short term by construction plant,
• Increase in suspended solids resulting from proposed earthworks,
• Contaminated site run off; and
• Washout of pollutants by water used to extinguish a fire onsite during the operational phase.
Anaerobic Digestion Facility (New Earth)
It is understood to be located on former agricultural land (Ref. 13-20) and as such the potential for the disturbance of contamination would be minimal. During the construction phase however, there is the potential for accidental spills and an increase in suspended solids effecting water resources.
*Pre-application
13.8.3. As outlined above, it is considered that the residual effect of the Proposed
Development on ground conditions will be negligible provided that standard,
current guidelines are adopted in design and that appropriate mitigation
measures are applied (or minor beneficial if remediation occurs). Any adverse
cumulative effect therefore will be due to the effect of these other schemes,
rather than in combination with the Proposed Development. It is also assumed
that the cumulative schemes will all undertake suitable investigation and
assessment of ground conditions and apply appropriate control measures
during construction and operation, such that any mitigation deemed to be
necessary would be completed in line with available regulatory guidance in
order to maintain a negligible cumulative effect.
Operational Impacts
13.8.4. No cumulative effects are assessed for ground conditions during the
operational phase as all developments are expected to have addressed any
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May 2014 Page 13-42
contamination or geotechnical issues during the construction phase. It is
anticipated that the cumulative operational effects will therefore be negligible.
13.9. Impacts and Effects yet to be Determined
13.9.1. At the time of writing the soil and groundwater chemical results and
groundwater level monitoring from the site investigation were not available.
Following receipt of this information the final ES will be updated to include the
analytical findings and a description of the suitability of the DCO Site for the
Proposed Development and associated infrastructure.
13.9.2. In addition, to date, no soil and groundwater data is available for the pipeline
corridor. This will be required prior to construction to allow assessment of the
risks to the identified receptors, but it is not considered that this is required for
the final ES.
13.9.3. The required foundation design solution(s) for the Proposed Development Site
area has not yet been confirmed. Geo-environmental site investigation of the
construction footprint areas is being undertaken in order to establish the most
appropriate foundation design solution(s). It is noted that at the time of writing,
the data from this investigation is not yet available but will be included in the
final ES.
13.9.4. No controlled water risk assessments have been carried out for this PEI Report
as, at the time of writing, the results of the ground investigation, including
chemical analyses, were not available. This data and the need for a controlled
water risk assessment will be presented in the final ES.
13.10. References
Ref. 13-1. Landmark Envirocheck Report, 2013, Ref 50541985_1_1. October 2013.
Ref. 13-2. DEFRA (2004); Model Procedures for the Management of Land Contamination (CLR11).
Ref. 13-3. EA 2002. Industry in Avonmouth, A Guide to pollution Management. EA 2002.
Ref. 13-4. Keller Limited, 1996, Seabank Power Station, Avonmouth Site Remediation Works Completion Report, December 1996, 01.6417/COMREP. Including appended contamination report by PB Power September 2009.
Ref. 13-5. McGill Archaeological Consultants, 2001, Pucklechurch to Seabank Pipeline- Archaeological Programme, October 2001.
Ref. 13-6. British Geological Survey Website www.bgs.ac.uk
Ref. 13-7. EA What’s in my Backyard (http://maps.environment-agency.gov.uk/wiyby/wiybyController?latest=true&topic=pollution&ep=query&lang=_e&x=352608.4791666669&y=179098.08333
Seabank 3 PEI Report – Chapter 13 Ground Conditions
May 2014 Page 13-43
33331&scale=11&layerGroups=1&queryWindowWidth=25&queryWindowHeight=25)
Ref. 13-8. Terradat. Geophysical Survey Report: UXO Scanning. Ref 3989. July 2013.
Ref. 13-9. C J Associates Geotechnical Limited. 2006. Crooks Marsh. Report T0925. December 2006.
Ref. 13-10. Building Research Establishment (BRE211), 2007, RADON. Guidance on protective measures for new buildings. 2007.
Ref. 13-11. NHBC/EA, 2008, Guidance for the Safe Development of Housing on Land Affected by Contamination. R&D Publication, 2008.
Ref. 13-12. EA ‘Framework for the Classification of Contaminated Soils in Hazardous Wastes’, version 1
Ref. 13-13. EA, 2005, Guidelines on sampling and testing of wastes to meet landfill waste acceptance procedures’ version 1.
Ref. 13-14. EA, 2001, Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention. 2001.
Ref. 13-15. Seabank Power Limited Production. Bulk Storage of Chemicals Spreadsheet. 2009.
Ref. 13-16. Mott MacDonald, 2011, Avon Power Station: Preliminary Environmental Information Report, June 2011.
Ref. 13-17. SLR, 2009. Environmental Statement: Severn Road Resource Recovery Centre. September 2009.
Ref. 13-18. Helius Energy, 2009, Environmental Statement: Proposed 100 MWe dnc biomass fuelled electricity generating station, Avonmouth. February 2009.
Ref. 13-19. Angus Meek Architects, 2011, DP01 Design and Access Statement. 2038 Rockingham Park, Smoke Lane, Bristol. December 2011.
Ref. 13-20. New Earth Solutions Group, 2012, Proposed Anaerobic Digestion Facility at Willow Farm, Severn Road, nr Hallen. 2012
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14 Flood Risk, Hydrology and Water Resources
14.1. Introduction
14.1.1. This chapter of the PEI Report assesses the potential effects of the Proposed
Development on flood risk, hydrology and water resources within the vicinity of
the DCO Site.
14.1.2. The potential surface water and groundwater receptors have been identified, with
consideration given to the potential effects during the construction (including
enabling works), operation, and decommissioning phases of the Proposed
Development and associated infrastructure. Incorporated design mitigation,
together with the need for site specific mitigation measures to protect the water
environment have been addressed, along with the nature of residual effects
remaining after mitigation. The cumulative effect of the Proposed Development
along with other consented schemes has also been considered.
14.1.3. This PEI Report summarises the key elements of the Level 3 (Detailed) Flood
Risk Assessment (FRA), which is presented in Appendix J, Volume II of this PEI
Report. The aim of the detailed FRA is to assess the flood risk posed to the
Proposed Development and the effect of the Proposed Development on third
parties, beyond the DCO Site boundary. Mitigation measures to reduce potential
flood risk effects have also been identified. Residual risks are explained and
management measures have been outlined.
14.1.4. The realignment of the Red Rhine (around the northern boundary of the
Proposed Development Site) is being delivered by a third party, Severnside
Distribution Land Ltd under extant planning permission and has been consented
by the Lower Severn Internal Drainage Board (LSIDB). The new Red Rhine
channel will be constructed prior to commencing enabling works onsite (at the
time of writing work had already commenced) and will be considered as part of
the ‘future baseline’ situation onsite. The diversion of flow from the existing Red
Rhine channel into the diversion channel will however form part of the enabling
works for the Proposed Development.
14.1.5. The infilling of the existing Red Rhine channel forms part of the DCO Application,
as does the diversion of a small tributary that currently flows into the Red Rhine
in a northerly direction from land owned by third party to the south of the CCR
Site, known as Crook’s Marsh (hereafter referred to as the ‘Crook’s Marsh
Stream’).
14.1.6. As part of the associated infrastructure, an underground pipeline is proposed to
supply cooling water to/from the Bristol WWTW and the Proposed Development.
The new water pipeline will be approximately 800mm in diameter, located within
a 30m wide corridor adjacent to the existing pipelines which are used to
supply/return cooling water to Seabank 1 & 2.
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Consultation
14.1.7. Consultation with the EA, SGC, BCC, Bristol Water, the LSIDB and Wessex
Water has been undertaken to inform the preparation of this PEI Report.
14.1.8. A Scoping Report (Ref. 14-1) was submitted to the Planning Inspectorate in
February 2013 to allow stakeholders the opportunity to comment on the proposed
structure, EIA methodology and content of this chapter and FRA.
14.1.9. The Planning Inspectorate issued a formal Scoping Opinion (Ref. 14-2) in March
2013. The EA, SGC, and the Marine Management Organisation (MMO) provided
specific guidance for the preparation of this chapter. No comments relevant to
this chapter were received from BCC.
14.1.10. A summary of stakeholder Scoping Opinion comments and how they have been
incorporated into this PEI Report chapter are provided in Table 14-1.
Table 14-1: Relevant Scoping Opinion Responses (issued by the Planning Inspectorate)
Stakeholder Comment Addressed within the Report
Planning
Inspectorate
The assessment should include an
assessment of impacts on water quality.
See section 14.5 and the Level 3 FRA
provided in Appendix J, Volume II.
The FRA should cover tidal flood risk as
well as fluvial impacts and therefore
should consider the potential for
breaching/overtopping of the flood
defence under present and projected sea
level scenarios.
See section 14.5 and the Level 3 FRA
provided in Appendix J, Volume II.
The ES should assess potential impacts
should the diversion of the Red Rhine not
go ahead, or its delivery is otherwise
delayed.
The Proposed Development could and
would not be built prior to the diversion
of the Red Rhine.
EA It may be appropriate to carry out detailed
site specific tidal modelling (breach and
overtopping) to ensure the Proposed
Development is protected over its
development lifetime.
The Level 3 FRA summarised in this
chapter and provided in Appendix J,
Volume II reports on the site specific
tidal modelling (including breach and
overtopping assessment).
SGC The scope of this ES Chapter is generally
appropriate but the chapter should
consider the Avonmouth Severnside
Level 2 Strategic Flood Risk Assessment.
The Local Planning Policy is
summarised in Appendix J, Volume II of
this PEI Report and includes a brief
summary of the SFRA. The site specific
modelling undertaken for the Level 3
FRA provides further detail to the
strategic modelling undertaken as part
of the SFRA.
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Stakeholder Comment Addressed within the Report
MMO The MMO acknowledges that the option
of direct cooling using water from the
estuary has been discarded due to a
combination of technical and
environmental challenges. However, if
direct cooling is selected as the preferred
option a number of marine environmental
impacts will need to be considered.
The direct cooling option has not been
selected therefore this chapter does not
include an assessment of marine
environmental impacts.
Data Sources
14.1.11. Baseline data on water resources and flood risk in the vicinity of the Proposed
Development have been collated by reference to the following sources:
• Environment Agency Groundwater Vulnerability Map of the Southern
Cotswolds (Sheet 37), 1:100,000 Scale (Ref. 14-3);
• Ordnance Survey (OS) Landranger Map, Bristol and Bath (Sheet 172),
1:50,000 Scale (Ref. 14-4);
• Avonmouth / Severnside Level 2 Strategic Flood Risk Assessment (March
2011). Prepared for Bristol City Council, South Gloucestershire, Lower
Severn Internal Drainage Board (Ref. 14-5);
• Severn Tidal Tributaries Catchment Flood Management Plan (December
2009). Prepared by the Environment Agency (Ref. 14.6);
• Landmark Envirocheck Report (September 2012) (Ref. 14-7). Information
on groundwater vulnerability, sensitive land uses, and surface water and
groundwater abstractions;
• Water Framework Directive (WFD) – River Basin Management Plans
(RBMP) – Rivers and Groundwater (Ref. 14-8). Information on water
quality data;
• Groundwater Aquifer Designation Map (Ref. 14-9). Information on
superficial drift and bedrock geology;
• Groundwater Source Protection Zone Map. Information on groundwater
protection zones in relation to public water supply (Ref. 14-10);
• Environment Agency Flood Map (Ref. 14-11). Information on Flood Zone
2 and 3 extents;
• Environment Agency Map of Flood Risk from Reservoirs (Ref. 14-12).
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14.1.12. In addition, specifically commissioned reports and investigations undertaken for
the DCO Site include:
• URS (2014) Seabank 3 CCGT Plant Level 3 Flood Risk Assessment;
• URS (2014) Seabank 3 CCGT Plant Hydraulic Modelling Report. Provides
details of hydraulic modelling undertaken to inform the Seabank 3 site
(provided in Annex J1 of the Level 3 FRA).
Legislation and Planning Policy Context
14.1.13. The legislation, planning policy and regulations specific to this chapter are
provided in Appendix D, Volume II of this PEI. Key Directives include:
• Water Framework Directive (WFD) (Directive 2000/60/EC) (Ref. 14-13) -
establishes a framework for a European wide approach to action in the
field of water policy. A water body is assessed for Ecological Status and
Chemical Status as part of the WFD, with the EA classifying water bodies
as either: High, Good, Moderate, Poor or Bad; and
• Groundwater Daughter Directive to WFD (Ref. 14-14) - seeks to establish
specific measures as provided for the WFD in order to prevent and control
groundwater pollution.
14.2. Assessment Methodology and Significance Criteria
Source Pathway Receptor Model
14.2.1. The determination of environmental effects has been undertaken using the
Source-Pathway-Receptor model. This model identifies the potential sources or
‘causes’ of effects, as well as the receptors (water resources) that could
potentially be affected.
14.2.2. However, the presence of a potential source and a potential receptor does not
always infer an effect will be generated, there needs to be a pathway or
‘mechanism’ via which the source can have an effect on the receptor.
14.2.3. The first stage in utilising the Source-Pathway-Receptor model is to identify the
causes or ‘sources’ of potential effects from a development. The sources have
been identified through a review of the details of the Proposed Development,
including its size and nature, potential construction methodologies and
timescales.
14.2.4. The next stage in the assessment is to undertake a baseline review of potential
receptors, that is, the water resources themselves that have the potential to be
affected. The final stage of the assessment is to determine if there is a pathway
or ‘mechanism’ allowing an effect to potentially occur between source and
receptor.
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Significance Criteria
14.2.5. Once potential effects to water resources are identified, it is necessary to
determine how significant the effects are likely to be, to enable the identification
of potential mitigation measures that can counteract adverse effects. The effect
on the receptors depends largely on the sensitivity of the receptor and the
magnitude of change experienced.
14.2.6. An assessment of the significance of each potential effect was undertaken using
the methodology provided in the Web-based Transport Analysis Guidance
(WebTAG); specifically the Water Environment Sub-Objective WebTAG Unit
3.3.11 (Ref. 14-15). The methodology set out in this WebTAG Unit provides an
appraisal framework for taking the outputs of the EIA process and analysing the
key information of relevance to the water environment.
14.2.7. The guidance provides a method by which the significance of the identified
potential effect can be appraised consistently by decision makers. It is based on
guidance prepared by the EA and builds on the water assessment methodology
in the Design Manual for Roads and Bridges (DMRB) (Ref. 14-16). Although this
method was designed for transport projects, it is applicable to, and widely used
for, other development types.
14.2.8. The methodology provides an assessment of the significance of an effect by
firstly considering how important or how sensitive the receptor is and secondly,
by considering the likely magnitude or extent of the change on the receptor. By
combining these two elements, the magnitude of an effect can be derived. If
significant adverse effects are identified, mitigation measures can be proposed to
offset them.
14.2.9. The sensitivity or importance of each water resource (the receptor) is based on
its considered value, for example as an ecological habitat, a source of drinking
water or a recreational resource, as outlined in Table 14-2.
Table 14-2: Derivation of Importance of Water Resource
Importance Criteria Example
Very High Water resource with an importance and rarity at an international level, with limited potential for substitution.
Principal aquifer providing potable water to a large population.
High Water resource with a high quality and rarity at a national or regional level, and with limited potential for substitution.
Principal aquifer providing potable water to a small population.
Medium Water resource with a high quality and rarity at a local scale; or Water resource with a medium quality and rarity at a regional or national scale.
Secondary aquifer providing potable water to a small population.
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Importance Criteria Example
Low Water resource with a low quality and rarity at a local scale.
A non-main river or stream which is not considered significant ecological habitat.
14.2.10. The magnitude of a potential effect is then established based on the likely degree
of change relative to the nature and extent of the Proposed Development, as
shown in Table 14-3. It is important to consider at this stage that potential effects
can be beneficial as well as adverse. The derivation of magnitude is carried out
independently of the importance of the water resource.
Table 14-3: Derivation of Magnitude of Change
Magnitude of change Criteria Example
High Change results in a shift in a water body’s potential attributes, which is clearly significant.
Pollution / remediation of potable source of abstraction resulting in failure / recovery above drinking water standards.
Medium Results in a change to integrity of attribute or loss of part of attribute, which is considered significant.
Loss / gain in productivity of a fishery.
Contribution / reduction of a significant proportion of the effluent in a receiving river, but insufficient to change its WFD classification.
Low Results in a slight change on a water body’s attribute that is not significant.
Measurable changes in attribute, but of limited size and / or proportion.
Neutral Results in an imperceptible change to an attribute that does not affect its use / integrity.
Physical change to a water resource, but no significant reduction / increase in quality, productivity or biodiversity.
No significant change to the economic value of the feature.
14.2.11. Once the magnitude of change is understood, the significance of the potential
impact can then be derived by combining the assessments of both the
importance of the water resource and the magnitude of the change in a simple
matrix, as shown in Table 14-4.
14.2.12. The methodology adopted for this chapter considers major or moderate effects to
be significant, and minor or negligible effects not to be significant.
Table 14-4: Derivation of Effect Significance
Magnitude of Change
Importance of Water Resource (receptor)
Very High High Medium Low
High Major Major Moderate Moderate
Medium Major Moderate Moderate Minor
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Magnitude of Change
Importance of Water Resource (receptor)
Very High High Medium Low
Low Moderate Minor Negligible Negligible
Neutral Minor Negligible Negligible Negligible
Flood Risk Methodology
14.2.13. The specific methodology for defining and assessing flood risk is dictated by the
requirements of the NPPF (Ref. 14-17). Planning Practice Guidance released in
March 2014 (Ref. 14-18) provides additional advice to local planning authorities
to ensure the effective implementation of planning policy on development in
areas at risk of flooding. The full details of this methodology for assessing flood
risk are outlined in the Level 3 FRA document included within Appendix J,
Volume II of this PEI Report.
14.2.14. For the purpose of this chapter the flood risk to identified receptors is considered
in the context of existing site conditions, the construction phase (including
enabling works) and once the Proposed Development is operational.
14.2.15. In the context of Table 14-2 the importance of the Proposed Development is
classified as ‘high’ based on the reasoning that the development is critical
infrastructure of national importance with limited potential for substitution. The
neighbouring property and land is also used for industrial development of national
or regional importance and is therefore classified as ‘high’ importance.
Water Framework Directive Assessment
14.2.16. A further assessment step has been taken to determine whether an effect is likely
to result in a deterioration of a water body from its current status, or prevent a
water body from achieving ‘Good Status’ (or potential) in the future.
14.2.17. If either of these effects are predicted to occur, this is deemed to be a major
adverse effect to acknowledge that, under the WFD all water bodies must meet
the objectives irrespective of its current status (and hence perceived ‘importance’
in an EIA context).
Key Parameters for Assessment
14.2.18. This assessment employs the ‘Rochdale Envelope’ approach (as detailed in the
Planning Inspectorate Advice Note 9) and described in Chapter 2: The DCO and
EIA Process.
14.2.19. The variation in building dimensions presented in Chapter 4: Project Description
under the Rochdale Envelope principle is an important consideration for this PEI
Report, although do not significantly affect the input parameters utilised in either
the operational or construction water resources or water quality assessments.
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14.2.20. The FRA (and information from it that will be included in the final ES) has been
based on the worst-case footprints and heights. This will result in a predicted
maximum volume of water attenuation to maintain greenfield runoff rates from the
Site; this can be reduced if the detailed design post-consent reduces the area of
permeability.
14.3. Baseline Conditions
Introduction
14.3.1. This section summarises information on the baseline conditions of surface water
and groundwater receptors that have the potential to be influenced by the
Proposed Development. Potential water resource receptors have been
considered using data sources detailed in Section 14.1.
14.3.2. Particular attention is given to identifying any notably sensitive water bodies with
specific environmental targets or specific resource uses. A summary of baseline
flood risk information from the Level 3 FRA (Appendix J, Volume II of this PEI
Report) is also presented below.
Surface Water Receptors
14.3.3. Figure 14-1 (Volume III of this PEI Report) shows the location of watercourse
features and catchment areas in the vicinity of the DCO Site, which are described
below.
Hydrology
14.3.4. The Red Rhine flows directly through the Proposed Development Site in an east
to west direction towards the Severn Estuary. The Red Rhine is currently a
relatively small man-made drainage channel, embanked on both sides. Along the
majority of its length the Red Rhine comprises a 3m base, in an approximately
1.5m deep channel, with a top width of between 8m and 11m.
14.3.5. The Red Rhine catchment is a flat low lying catchment with a total catchment
area of 6.7 square kilometres (km2). The Red Rhine is fluvially dominated and
discharges into the tidal River Severn at New Pill Gout, approximately 600m
downstream of the Proposed Development Site. Prior to discharge to the tidal
River Severn, the Red Rhine enters a culvert through the (A403) road
embankment, a sluice gate (located between the road embankment and railway
embankment) and a large underpass beneath the railway embankment.
14.3.6. The Red Rhine catchment includes the existing Seabank 1 & 2 generating station
and a number of other consented schemes (see Section 14.7). West of the
Proposed Development Site, a third party has begun construction of the
consented Severnside Energy Recovery Centre, and to the north there is
cleared, hardstanding land where Terra Nitrogen and ICI used to operate. The
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Avonmouth LNG Storage Facility is located upstream (to the southeast) of the
Proposed Development Site. The M49 crosses the catchment area from north to
south, approximately 1.5km east of the Proposed Development Site. The
northern edge of Hallen is also located within the southern extent of the Red
Rhine catchment.
14.3.7. A number of smaller tributaries flows into the Red Rhine and criss-cross the
Proposed Development Site currently. These will need to be realigned to drain
into the new Red Rhine channel. The most important of these tributaries is
Crook’s Marsh Stream’ that flows from the south of the CCR Site, joining the Red
Rhine near the northeast corner of the CCR Site.
14.3.8. The Stuppill Rhine is located approximately 1km to the south of the Proposed
Development Site and crosses the DCO Site approximately half way along the
length of the proposed cooling water pipeline corridor. The catchment for this
rhine is flat and low lying (similar to the Red Rhine catchment) and drains a total
area of 2.2km2. The Stuppill Rhine is not hydrologically linked to the Red Rhine,
as both discharge directly into the tidal River Severn and therefore, no impact on
the Stuppill Rhine is anticipated during the construction or operation phase of the
main Proposed Development. However, the Stuppill Rhine is the most significant
watercourse traversed by the proposed cooling water pipeline corridor and
requires consideration as part of this assessment.
14.3.9. The Redwick Common Rhine is located approximately 2km to the north of the
Proposed Development Site. This flat, low lying catchment drains a total area of
8.1km2. A number of other minor rhines are present within this catchment area.
The land-use within this catchment is less industrial than the Red Rhine and
Stuppill Rhine catchments and includes residential areas of Easter Compton and
Severn Beach. The Redwick Common Rhine is not hydrologically linked to the
Red Rhine, as both discharge directly into the tidal River Severn. The Redwick
Common Rhine does not cross the DCO Site and therefore, no impact on the
Redwick Common Rhine is anticipated during the construction or operation
phase of the Proposed Development.
Site Drainage
14.3.10. The Proposed Development Site is predominantly flat and low-lying and poorly
drained with frequent areas of standing surface water and marshland. A review of
OS mapping (Ref. 14-4) indicates that the southern end of the Site is an area
known as Crook’s Marsh.
14.3.11. The Proposed Development Site is dissected by several minor drainage channels
and a major channel (the Red Rhine) running in a north-west direction through
the centre of the site.
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14.3.12. Prior to commencing enabling works for the Proposed Development the new Red
Rhine channel is anticipated to have already been cut around the northern
boundary of the Proposed Development Site by Severnside Developments Land
Ltd and is therefore considered as part of the ‘future baseline’; this work is
currently underway at the time of writing and is expected to be completed by the
first quarter of 2015.
14.3.13. The diversion of flow from the existing channel into the new diversion channel will
form part of the enabling works, as will the infilling of the existing channel.
14.3.14. The diversion of the Crook’s Marsh Stream (tributary of the Red Rhine) (see
Figure 14-1, Volume III of this PEI Report) also forms part of the DCO
Application. The Crook’s Marsh Stream will be diverted across the eastern corner
of the CCR Site to the diverted Red Rhine.
Coastal Waters
14.3.15. The Red Rhine discharges to the tidal River Severn approximately 600m
downstream of the Proposed Development Site. The tidal River Severn is
therefore the ultimate downstream surface water receptor from the Proposed
Development Site.
14.3.16. As identified on Figure 14-1 (Volume III of this PEI Report), this part of the River
Severn is statutory designated as a SSSI and internationally recognised as a
SAC, SPA and Ramsar site. It is also internationally recognised as an Important
Bird Area (IBA).
Surface Water Quality and Ecological Status
14.3.17. The EA measures water quality of inland surface waters (rivers and lakes),
transitional waters (estuaries), coastal waters and groundwater with reference to
standards set by the WFD.
14.3.18. The WFD seeks to ensure all controlled water bodies achieve 'good status /
potential' by 2015 (or 2027 if extensions are permitted). This overall status takes
into account the biological, chemical, hydro-morphological and specific pollutants
quality of the water body.
14.3.19. As part of the EIA, water quality data has been requested from the EA.
Unfortunately the spatial and temporal data coverage for this area is limited.
However, the EA has provided interim WFD classification results for the Redwick
Common Rhine (from source to confluence with the Pill) for 2012.
14.3.20. This data indicates that the Redwick Common Rhine is classified as having an
overall ‘poor’ current ecological potential, based on a poor biological and a ‘not
high’ hydromorphological quality. The Redwick Common Rhine is classified as a
highly modified water body, designated due to being an artificial drainage
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channel. The WFD objective for Redwick Common Rhine is to achieve ‘good’
ecological potential by 2027.
14.3.21. From observations made during the site walkover and a review of geological and
OS mapping, the Red Rhine and Stuppill Rhine are considered to share similar
catchment characteristics to the Redwick Common Rhine, in terms of land-use,
typology and hydro-morphological status (i.e. artificial drainage channels).
14.3.22. Therefore, in the absence of WFD classification data for the Red Rhine and
Stuppill Rhine it is considered reasonable to assume that the Red Rhine and
Stuppill Rhine can also be classified as having an overall ‘poor’ current ecological
potential WFD classification, similar to the Redwick Common Rhine.
Surface Water Abstractions and Discharges
14.3.23. The locations of water abstraction and discharge consents held within the vicinity
of the Proposed Development Site are shown in Figure 14-1(Volume III of this
PEI Report).
14.3.24. The Envirocheck Report (Ref. 14-6) for the Proposed Development Site and
surrounding area indicates that no abstraction licences and nine discharge
consents licences are held within the Red Rhine catchment area. Discharge
consents located closest to the Proposed Development Site (approximately 500m
from the Site boundary) are operated by Wessex Water. These allow discharge
of treated sewage effluent and storm water overflow to tributaries of the Red
Rhine.
14.3.25. No abstraction licences exist within 200m of the proposed cooling water pipeline
corridor. There are 18 discharge consents located within (or bordering) the
Stuppill Rhine catchment, with a number of these located in close proximity to the
proposed cooling water pipeline corridor.
14.3.26. These discharge types are for surface water and trade effluent discharges from
local industry, or sewage discharges from the Bristol WWTW. All licences allow
discharge to surface waters along the local rhine network.
14.3.27. SGC and BCC have confirmed that no properties within the vicinity of the DCO
Site are listed on their private water supply registers.
Groundwater Receptors
14.3.28. Geology, hydrogeology and land contamination is considered in detail in Chapter
13: Ground Conditions. However, a review of available geology and
hydrogeology data has also been undertaken to inform this chapter of the PEI
Report.
14.3.29. A summary is provided in the following sections.
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Geology
14.3.30. Superficial deposits underlying the DCO Site are Quaternary age Tidal Flat
deposits consisting of normally consolidated soft silty clay, with layers of sand,
gravel and peat. The bedrock comprises Triassic age Mercia Mudstone Group
described as dominantly red, less commonly green-grey, mudstones and
subordinate siltstones.
14.3.31. Table 14-5 presents a summary of the geological strata encountered during the
2013 ground investigation based on the draft logs available at the time of writing
(BH001, BH003, BH004, BH005 and BH006).
Table 14-5: Summary of Site Geological Strata
Strata Depth Range (m bgl) Description
Reworked Natural Ground
0 – 0.30 Firm dark brown slightly sandy clay with frequent rootlets. (Identified in BH004 only)
Tidal Flat Deposits 0.20 – 14.00
Firm, locally soft, fissured brown mottled grey silty Clay. Occasional fragments of partially decomposed plant material and occasional PEAT.
Weathered Mercia Mudstone Group
9.00 – 17.50 Very stiff fissured dark reddish brown grey silty clay.
Mercia Mudstone Group
11.95 – base not proven Extremely weak dark reddish brown mudstone interbedded with extremely weak to weak light greenish grey sanstone.
m bgl: metres below ground level
Hydrogeology
14.3.32. The EA Groundwater Aquifer Designation Map (Ref. 14-9) indicates that the
bedrock underlying the DCO Site, which includes the proposed cooling water
pipeline corridor, is classified as a Secondary B Aquifer; predominantly lower
permeability layers which store and yield limited amounts of groundwater due to
localised features such as fissures, thin permeable horizons and weathering.
Generally the water-bearing parts are of the former non-aquifers. The superficial
deposits on the site are classified as unproductive strata.
14.3.33. The EA Groundwater Vulnerability Map (Ref. 14-3) indicates that the underlying
geology beneath the entire DCO Site (including the water supply pipeline route)
is Non-Aquifer of negligible permeability and located outside of a Groundwater
Source Protection Zone.
Groundwater Quality
14.3.34. The EA WFD River Basin Management Plan (Ref. 14-8) indicates that the
groundwater quality (quantitative) underlying the DCO Site and surrounding area
is classified as ‘good’ and is predicted to remain ‘good’ for the foreseeable future.
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Similarly, the current chemical quality is ‘good’ and is also predicted to remain
‘good’ in 2015.
Water Supply and Sewage Infrastructure
14.3.35. Bristol Water is responsible for water supply within the vicinity of the DCO Site.
Liaison with Bristol Water has confirmed that a 24” (610mm) diameter trunk main
is located within the Proposed Development Site boundary, as shown in Figure 3-
1 in Volume III of this PEI Report. This mains water pipe used to supply water to
the former Terra Nitrogen and ICI site immediately north of the Proposed
Development Site and an off-take from this pipeline currently supplies the
Seabank 1 & 2 generating station.
14.3.36. Wessex Water is responsible for the sewage infrastructure within the DCO Site
and has confirmed that no sewage infrastructure exists within the vicinity of the
DCO Site. However, two 540mm and 560mm underground pipelines are known
to supply and return cooling water from the Bristol WWTW to/from the Seabank 1
& 2 station.
Flood Risk
14.3.37. The Level 3 FRA (see Appendix J, Volume II of this PEI Report)) indicates that
the entire DCO Site is located within Flood Zone 3a and that the Proposed
Development is classified as ‘Essential Infrastructure’. This type of development
is only permitted within Flood Zone 3a where it can be demonstrated that the
Exception Test has been passed.
14.3.38. To satisfy the requirements of the Exception Test the Level 3 FRA assesses the
risk posed to the Proposed Development and its impact on third party property. A
hydraulic model has been developed to further understand fluvial and tidal flood
risk associated with the Proposed Development Site, as shown in Annex J1 of
the FRA. It has not been necessary to model the proposed electrical cable route
or cooling water pipeline, the latter of which will be buried underground and the
former will be either underground or routed to the substation on a cable rack
inside a waterproof casing to protect against water damage through Seabank 1 &
2.
14.3.39. The model results have been used to inform suitable design mitigation measures
(see Section 14.5) to ensure that the Proposed Development and site users
remain safe over the development lifetime and ensure flood risk to third parties is
not increased. These measures are intended to ensure that the requirements of
the Exception Test are passed.
14.3.40. The following paragraphs summarise the existing baseline flood risk conditions,
for all sources of flooding, as identified within the Level 3 FRA.
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Fluvial
14.3.41. The Level 3 FRA flood mapping outputs indicate that during the ‘existing
baseline’ scenario, flooding occurs in areas of the Proposed Development Site
during all fluvial events considered. During the 1 in 100 year (inclusive of climate
change) a peak flood depth of 0.52m is apparent along the lower lying southern
perimeter of the Proposed Development Site. The risk posed by fluvial flooding to
the Proposed Development and wider Proposed Development Site is therefore
considered high.
Tidal
14.3.42. The Level 3 FRA flood mapping outputs indicate that during the 1 in 200 year
(inclusive of climate change) tidal event combined with the 1 in 100 year fluvial
event (inclusive of climate change) the DCO Site is inundated with floodwaters.
However, the increase in flood depth is minimal (0.01m) when compared to the
equivalent fluvial only event where no extreme tidal component is considered.
14.3.43. Therefore, the actual risk posed to the Proposed Development Site and wider
DCO Site by tidal flooding is considered low. However, a residual risk due to
potential tidal defence breach still remains. This is discussed further in the
impacts and mitigation section (Section 14.5).
Other Flood Sources
14.3.44. The risk of flooding from other sources, such as surface water, sewer,
groundwater and artificial sources is deemed to be low or negligible.
Baseline Summary
14.3.45. A summary of surface water and groundwater receptors identified in the baseline
conditions including their allocated importance classification (based on the
criteria shown in Table 14-2) is provided in Table 14-6. Table 14-6 also indicates
whether the surface or groundwater receptor is considered further in the
assessment (based on a review of baseline conditions) and provides justification
for the decision made.
14.3.46. A summary of the risk posed by all flood sources, including an indication of
whether they are considered further within this PEI Report is provided in Table
14-7.
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Table 14-6: Summary of Surface and Groundwater Receptors
Receptor Importance / sensitivity
Considered Further in Assessment
The Red Rhine (including Crook’s Marsh Stream)
High Yes – flows and water quality potential affected by the Proposed Development
The Stuppill Rhine (and minor tributaries)
High Yes – Stuppill Rhine represents the most significant watercourse traversed by the proposed cooling water pipeline corridor
The Redwick Common Rhine (and minor tributaries)
High No – Not hydrologically linked, therefore no impact to watercourse anticipated
Tidal River Severn Very High Yes – Ultimate downstream receptor
Shallow Groundwater High Yes –Shallow groundwater encountered at the DCO Site and is considered to be hydrologically linked to surface waters
Deeper Groundwater High Yes – Shallow and deeper groundwater at the DCO Site are considered to be hydrologically linked
Table 14-7: Summary of Risk Posed by all Flood Sources
Flood Source Level of Risk
Considered Further in Assessment
Fluvial High Yes – Design mitigation required to reduce risk posed to the Proposed Development to an acceptable level
Tidal (Actual) Low Yes – Mitigation proposed for fluvial and residual tidal risk will further reduce actual tidal risk
Tidal (Residual) High Yes – Design mitigation required to manage residual risk in the event of a failure or breach in the flood defences
Surface Water / Sewer Low Yes – Design mitigation required to manage surface water runoff from the Proposed Development using SuDS measures
Groundwater Low No – Not considered to pose a significant risk to the Proposed Development
Artificial Sources Negligible No – Not considered to pose a significant risk to the Proposed Development
14.4. Development Design and Impact Avoidance
14.4.1. A number of avoidance measures that are being implemented in the design of
the Proposed Development are relevant to flood and hydrology.
14.4.2. In particular, hydraulic modelling demonstrated a need to achieve a minimum
finished floor level of 8.31m AOD to protect against flood risk, which has been
increased to a commitment to raise the Generating Station Site to up to 8.5m
AOD to reduce the level of precision required by a Contractor.
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14.4.3. In addition, land has been allocated for a surface water attenuation pond of
capacity equal to the maximum required, based on the calculations in the FRA.
14.5. Potential Effects and Mitigation Measures
14.5.1. The Proposed Development and associated infrastructure have the potential to
affect water resources features within the area. Effects arising as a result of the
development, both beneficial and adverse, could affect the Proposed
Development’s ability to satisfy the criteria outlined within the relevant local,
national and European planning policy and legislation.
14.5.2. The significance of any effect depends on the sensitivity of the water resources
and the current conditions of such resources, the magnitude of any change and
the implementation of any mitigation measures during construction and
operation.
14.5.3. The following section takes into account both design mitigation incorporated into
the Proposed Development and additional measures such as management
controls or physical measures to further manage identified effects deemed to be
significant.
14.5.4. The significance of effects pre-mitigation is not provided in this section, with the
significance identified for residual effects only (see Section 14.6). It has been
assumed that any construction effects (short and medium term) are temporary
and any operational effects (long term) are permanent, unless otherwise stated.
Construction Phase
14.5.5. The enabling works and construction phase of the Proposed Development and
associated infrastructure have the potential to affect both surface water and
groundwater bodies located in the vicinity of the works.
14.5.6. Construction activities which give rise to such effects are described in Chapter 4:
Project Description and Chapter 5: Enabling Works and Construction.
Water Quality
14.5.7. Key activities and their potential effects include:
• Removal of topsoil and excavation required for the proposed cooling
water supply pipeline and raising of the Proposed Development Site
above design flood levels during construction. This will require the
temporary storage of stockpiles of soil and construction materials. Without
adequate mitigation this has the potential to increase the generation of
surface water runoff with elevated concentrations of sediment, which may
have a temporary adverse effect on the water quality of local surface
water receptors;
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• Piled foundations for the larger structures associated with the Proposed
Development is likely to penetrate the water table, which Chapter 13:
Ground Conditions states as being measured as 2.06m bgl and 2.54m
bgl. As a result there is potential for groundwater to seep into such
excavations, and therefore, dewatering may be required to allow
construction to continue. This activity may have a temporary adverse
effect on groundwater and surface water flows paths, and draw in
potentially contaminated water and open pathways between the shallow
and deeper groundwater bodies;
• The transportation, storage and use of oils and fuels for construction plant
and handling of wet cement and/or concrete, will increase the risk of
accidental spillages and contamination of surface waters and/or
groundwater, which has the potential to result in a temporary adverse
effect on local surface and groundwater receptors without adequate
mitigation;
• Provision of onsite sanitary facilities for construction site staff could also
introduce an additional source of pollution, with the potential to cause
nutrient enrichment of receiving water bodies. This activity may have a
temporary adverse effect on surface water receptors; and
• Handling of construction waste materials and wastewater could also
introduce an additional source of pollution to local surface and
groundwater receptors resulting in a temporary adverse effect dependent
on the presence and extent of potential contamination sources.
Water Quantity
14.5.8. Key activities and their potential effects include:
• As part of the enabling works the water flow within the existing Red Rhine
channel will be diverted into the new diversion channel that Severnside
Distribution Land Ltd is currently constructing along the northern
perimeter of the Proposed Development Site. The Crook’s Marsh Stream,
a tributary of the Red Rhine, will also need to be diverted to accommodate
the Proposed Development. The proposed route of the water supply
pipeline will transverse the Stuppill Rhine and a number of other minor
drainage channels;
• To undertake these works it may be necessary to temporarily obstruct the
channels and divert the surface water flows around the excavation via use
of a pump system, which could lead to a temporary adverse effect on flow
rate and discharge volumes immediately downstream of works and
cessation of flow across an approximate 10m section of the channel bed;
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• Construction of the proposed cooling water pipeline corridor may require
temporary dewatering of the excavation in some locations where the base
of the trench lies beneath the water table. Dewatering may lead to a
reduction in water levels within the surrounding area and may focus
groundwater flow towards the trench. However, groundwater impacts
related to pipeline installation construction works will be of limited
duration, as the pipeline trench will be backfilled. Therefore there is
anticipated to be very limited impact due to temporary dewatering during
the construction phase. Furthermore no water abstractions are located in
close proximity to the new pipeline route, as indicated in the ‘Baseline
Conditions’ section of this chapter;
• The installation of the proposed cooling water pipeline corridor may
require the obstruction and diversion of minor watercourses, which are
discussed further below.
14.5.9. The electrical connection through the Seabank 1 & 2 site is not expected to have
any adverse effect on surface water of groundwater flow. It will either be above
ground in cable racks or installed beneath the existing Seabank 1 & 2 generating
station using HDD techniques.
Mitigation
General Mitigation Measures
14.5.10. Construction will take place in accordance with all relevant legislation for the
protection of surface and groundwater and codes of best practice guidance for
works on or near water. Several references are pertinent, including the Pollution
Prevention Guidelines prepared by the Environment Agency. The following
Pollution Prevention Guidelines (PPG) are of particular relevance to construction
site activities:
• PPG1: General guide to the prevention of pollution;
• PPG2: Above ground oil storage tanks;
• PPG5: Works in, near or liable to affect watercourses;
• PPG6: Working at demolition and construction sites; and
• PPG21: Pollution incident response planning.
14.5.11. The appointed Contractor will be required to prepare a method statement for
potentially polluting activities during the construction phase, to be included in the
CEMP. The method statement will describe how construction activities shall be
undertaken and managed in accordance with requirements identified within this
PEI Report and the final ES that will accompany the DCO Application.
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14.5.12. Surveillance monitoring of the Red Rhine (and Crook’s Marsh Stream) in the form
of routine visual observations will be undertaken immediately upstream and
downstream of the Proposed Development Site boundary, both prior to
construction (to establish baseline conditions) and then during the construction
phase.
14.5.13. The purpose of the surveillance monitoring will be to identify potential
contamination, such as the presence of oil spills and higher sediment loading,
and to indicate the need for further investigation such as spot monitoring of pH,
conductivity and dissolved oxygen. In the event of any significant deviation from
baseline conditions, samples will be taken for water chemistry laboratory analysis
covering a wide suite of water quality parameters.
Excavations and Land Raising
14.5.14. Bulk materials such as topsoil and excavated/fill material will be stored in
designated areas away from watercourses and, if deemed necessary by the
CEMP, covered to prevent erosion. The 8m maintenance access strip proposed
alongside the realigned Red Rhine is likely to be at a slightly lower ground level
than the Generating Station Site (following land raising, which is discussed
below) and will not be used for material stockpiles adjacent to the Red Rhine.
14.5.15. However, in general a minimum 10m buffer strip will be adopted for material
stockpiles from the Red Rhine to reduce pollution risks, where possible. Specific
guidance in dealing with silt arising from construction activities is contained within
PPG5, which will be taken into account within a CEMP.
14.5.16. As detailed in Chapter 13: Ground Conditions, intrusive investigations have been
undertaken on the Site to determine the presence of potential contaminant
sources. If found to be present, contamination would create potential constraints
to be resolved during the development works, however it is anticipated that these
can be managed through the correct use of the CEMP and CMS.
Channel Diversions and Pipeline Crossings
14.5.17. During the detailed design phase, temporary and permanent works will be
designed so as to minimise disruption to flows and disturbance to the
watercourse’s bed, channel and banks. A method statement for undertaking work
in the vicinity of any watercourse will be prepared by the Contractor and
approved in advance by the supervising engineer (for the Contractor) and where
necessary the LSIDB in order to minimise any potential impact on surface water
quality or flows.
14.5.18. A Flood Defence Consent will be sought from the LSIDB for the crossing of
Stuppill Rhine and other minor drainage channels as required. A method
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statement will also be produced and implemented through the CEMP for the
control of channel flows during this period.
Temporary Site Drainage
14.5.19. A detailed Drainage Management Plan will be produced following receipt of the
DCO to ensure contaminated water is appropriately managed and treated prior to
entering into any water body. A framework strategy for this Plan will be included
as part of the submission of the DCO. For example, where there is a requirement
for disposal of water from excavations (due to dewatering activities), water will be
treated (e.g. ‘on-site settlement tanks) to remove potential contaminants, prior to
being discharged to surface waters.
Storage and Use of Chemicals, Fuel/Oil and Other Construction Material
14.5.20. Construction of concrete structures would be monitored by the contractor as part
of the CEMP so that work is stopped and amended if contaminated material is
found to be entering any watercourses. Pre-cast work will be utilised where
possible to reduce the amount of in-situ concreting required adjacent and above
the watercourses.
14.5.21. Washing out of concrete wagons or other equipment used in concreting
operations is not planned onsite.
14.5.22. The positioning of fuel storage tanks and other potentially polluting materials and
maintenance/refuelling facilities will be within designated bunded areas with drip
trays placed on standing machinery to avoid pollution from spillages and leaks.
The volume of the bunded areas will be at least the capacity of the tank(s) plus
10%.
14.5.23. Spill kits will be made available, and construction site workers trained in their use,
to deal with any spillages. All spill kits will be fully stocked at all times and an
inventory of equipment within the container will be clearly displayed within the lid.
14.5.24. Stores of construction materials will be in bunded or kerbed areas. The drainage
system of the bund will be sealed with no discharge to any water body.
14.5.25. Foul water (consisting of sewage and domestic type waste water) from welfare
facilities on site will be discharged via the foul water connection in Seabank 1 & 2
or treated on site within a packaged sewage treatment plant. The treated effluent
will be discharged to a local sewer in Seabank 1 & 2.
14.5.26. Taking this mitigation into account the residual effect on water quality and water
quantity during operation is negligible to minor adverse, depending on the
sensitivity of the receptor.
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Fluvial/Tidal Flood Risk – Onsite Impacts
14.5.27. Unmitigated, the actual or residual risk posed to the Proposed Development from
fluvial and tidal sources is potentially high. To mitigate this risk, ground raising
across the Generation Station Site (an area of up to 8.5ha) is proposed based on
the findings of the detailed FRA.
14.5.28. The remainder of the Proposed Development Site is made up of the Utilities,
Services and Landscaping Area (6.4ha) which does not require additional flood
risk protection and a further 6.3ha that is reserved for carbon capture equipment
in the event that this is required in the future. In addition, as mentioned
previously, the Other DCO Land that contains the cooling water pipeline and
electrical connection is not vulnerable to flood risk and therefore does not require
mitigation.
14.5.29. The Level 3 FRA ‘future baseline’ scenario incorporates the Red Rhine diversion
and achieving a minimum finished floor level for the Proposed Development of
8.31m AOD, as shown to be required by the hydraulic modelling in Annex J1 of
the FRA (although the DCO Application incorporates the ability to raise the land
up to 8.5m AOD). The 8.31m AOD level represents the minimum finished floor
level for the Proposed Development; however, certain equipment such as the
cooling water system which can be bunded to protect them from flood risk may
not require land raising to this minimum level. For the purpose of this PEI Report
however it is considered a robust assumption and the worst-case scenario in
terms of potential flood water displacement, to assume minimum ground levels
for the Proposed Development will be 8.31m AOD.
14.5.30. The detailed FRA indicates that during the ‘future baseline’ scenario, land raised
within the Proposed Development Site boundary is predicted to remain dry for all
fluvial scenarios, including 1 in 1000 year (inclusive of climate change) event and
all tidal scenarios (including breach events) up to 1 in 200 year (inclusive of
climate change) event.
14.5.31. Depending on the timing of the flood event in relation to the extent of land raising
completed at that time, this mitigation could have a negligible to major
beneficial effect on the flood risk posed to the Proposed Development Site and
construction workers.
14.5.32. To ensure site evacuation occurs prior to the onset of a flood event the
construction site manager will register with the EA Flood Warning Service and
have a flood evacuation plan in place to ensure construction workers are
informed of the potential flood risk and appropriate actions to take during a flood
event (i.e. safe refuge).
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Fluvial/Tidal Flood Risk – Offsite Impacts
14.5.33. The offsite effect to neighbouring property and land resulting from the
displacement of floodwater associated with proposed land raising has been
considered. The floodwater displaced by the Proposed Development represents
only 1.4% of the total volume displaced during the extreme fluvial dominant flood
event and 5.4% during the tidal breach event.
14.5.34. The volume of floodwater displaced by the proposed land raising has been
considered in the FRA. The floodwater displaced by the Proposed Development
during the modelled tidal breach scenario is predicted to raise local flood levels
by 0.003m (3mm), when distributed across the flood cell (which covers an area of
47km2 and extends from Avonmouth in the south to the Severn Road Bridge in
the north.
14.5.35. This increase is considered to have a minor adverse effect on the flood risk
posed to third parties on adjacent land, reducing to negligible with distance from
the Site.
Surface Water Flood Risk
14.5.36. The surface water flood risk posed to the Proposed Development Site is
considered low. Proposed land raising is considered to have a minor beneficial
effect on the surface water flood risk posed to the Proposed Development Site
and construction workers.
14.5.37. Prior to the Site drainage network becoming operational, there is potential for a
temporary increase in rates and volumes of surface water runoff generated
across the Proposed Development Site, due to soil compaction and the gradual
increase in impermeable area.
14.5.38. To mitigate potential adverse effects, where required, temporary SuDS features
(such as swales / ditches) will be used in locations where preferential flow
pathways offsite are identified. These measures will be included in the Drainage
Strategy to accompany the DCO Application and the detailed Drainage
Management Plan, which will be produced following receipt of the DCO. Taking
these mitigation measures into account, the risk posed to third parties will remain
low and the residual effect is anticipated to be minor adverse, albeit temporary
in nature as a drainage strategy will be implemented for the operational
development.
Operational Phase
14.5.39. The potential to affect both surface water and groundwater bodies is significantly
reduced during the operation phase of the Proposed Development. The key
activities and potential effects are identified below.
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Water Quality and Quantity
Water Quality
14.5.40. Key activities and their potential effects prior to mitigation include:
• The increase in built hard surface areas (e.g. concrete) can lead to
flushing effects, whereby site runoff mobilises sediment accumulated over
time. Discharge to adjacent surface waters via drainage system could
potentially lead to sedimentation;
• Routine use / presence of lorries, cars and other vehicles across the site
and on access routes and associated activities such as re-filling distillate
tanks, accidental spillages and minor leaks all have the potential to
contaminate runoff in the locality with hydrocarbons or other chemicals;
• Water from the cooling water system returning to the Bristol WWTW is
expected to be on average 25-26 degrees Celsius (°C) when the
Proposed Development is in operation. Discharge of higher temperatures
of cooling water from the WWTW could have an adverse effect on the
receiving surface water;
• Potential for nutrient enrichment and contamination of water bodies as a
result of inadequate foul water drainage facilities.
14.5.41. Mitigation measures to minimise the risk of the above occurring and the
magnitude of change caused by such events, are outlined later in this chapter.
Water Quantity
14.5.42. Key activities and their potential effects include:
• On completion of the Proposed Development, surface water runoff from
the Site will be designed to be restricted to pre-development rates for the
1 in 100 year including climate change rainfall event (76 l/s) using SuDS
techniques in accordance with the Drainage Strategy and Drainage
Management Plan. Taking this into account, the operational phase is
anticipated to have a negligible effect on the hydrology of the local
drainage ditches (i.e. Red Rhine and Crook’s Marsh Stream).
• Cooling water will be supplied to the Proposed Development via the
proposed cooling water pipeline corridor connected to the Bristol WWTW.
The cooling water systems would have an initial demand of approximately
600 m3/hr, after which it becomes a closed system with approximately 1%
lost to evaporation and spillage which needs to be topped up
intermittently. In addition to this, the cooling water system will also be
flushed out and replaced periodically;
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• The cooling water received from the Bristol WWTW will be treated to its
required effluent discharge standards. For use within the generating
station’s process, the cooling water requires additional treatment / dilution
to make it suitable for use, using the Seabank 1 & 2 chemical treatment
plant. It may also require dilution using towns mains (potable) water to
achieve water quality levels required for use in the generating station. The
cooling water supply is therefore considered to have a permanent
beneficial effect on water quality as the water should be returned to the
WWTW cleaner than it was supplied and can subsequently be used to
dilute Wessex Water's discharges into the estuary;
• The installation of the proposed cooling water pipeline corridor is not
anticipated to have a significant effect on shallow groundwater flows when
compared to baseline conditions. A significant amount of the excavation
will be within made ground which is already disturbed from its natural
condition, most likely during the installation of the existing water supply
pipeline for Seabank 1 & 2. The majority of the pipeline is expected to be
above the water table, and providing adequate water stops are included
within saturated sections of the pipeline trench to avoid groundwater
eroding the backfill material and creating new pathways, significant
permanent alteration in the regional groundwater flow regime is not
considered likely to occur. In addition, no water abstractions which could
be adversely affected have been identified in close proximity to the
proposed route of the pipeline.
• The electrical connection through the Seabank 1 & 2 site is not expected
to have any adverse effect on surface water of groundwater flow during
operation as previously discussed.
Mitigation Measures
14.5.43. To minimise the risk of pollution entering controlled waters during the operational
phase the following measures will be implemented:
• Surface water from areas with a low risk of contamination with oils will be
discharged via silt traps to a local surface water body. In areas onsite
where there is an increased risk of runoff containing pollutants such as
oils and hydrocarbons (such as car parking areas), surface water will be
pass through an oil interceptor prior to discharge to a local surface water
body;
• Any operational activities that carry significant risk of oils / hydrocarbon
spillage will comply with EA guidance PPG1 and PPG5 and shall be
incorporated into the management procedures associated with the
operation of the generating station;
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• Foul drainage will be treated at an onsite treatment plant prior to being
discharged to the Bristol WWTW via the cooling water return flow pipe;
• Prior to discharge to estuary via the Bristol WWTW, Wessex Water mix
the cooling water from the water supply pipeline with other effluent from
the WWTW, which should lower the discharge temperature. Effluent
discharge from the Bristol WWTW is controlled by a discharge consent
which requires Wessex Water to achieve a certain discharge temperature;
• Regular pipeline inspection and monitoring will ensure that significant
uncontrolled discharges are detected in a timely fashion. Contingency
plans will be set up to minimise the impact of uncontrolled discharge
resulting from any breach in the pipeline. Should repair work be required
to the water supply pipeline, then the general mitigation measures as
discussed for the construction phase will be implemented to minimise the
impact of the works;
• Surveillance monitoring will be carried out on the Red Rhine onsite once
the Proposed Development is operational as part of the Site’s
environmental duties. Where a visual inspection indicates discolouration
to surface waters, further water quality samples will be taken for water
chemistry laboratory analysis covering a wider suite of water quality
parameters. A record of water quality results would be maintained for EA
review.
14.5.44. Taking this mitigation into account the residual effect on water quality during
operation is anticipated to be negligible to minor adverse, depending on the
receptor; the latter is due to a low magnitude of change on a high importance
receptor, which is shallow groundwater.
Fluvial/Tidal Flood Risk - Onsite
14.5.45. Land within the Proposed Development Site boundary will be raised above
modelled flood levels and include a freeboard allowance to account for potential
uncertainties in model and climate change predictions over the development
design life (i.e. 30 years). This mitigation will have a major beneficial effect on the
risk posed to the Proposed Development Site, by reducing the tidal/fluvial flood
risk to low.
14.5.46. To ensure site evacuation occurs prior to the onset of a flood event during the
operational phase the Site Manager will register with the EA Flood Warning
Service and have a Flood Emergency Plan to ensure site workers are informed of
the potential flood risk and appropriate actions to take during a flood event (i.e.
safe refuge).
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14.5.47. To ensure that evacuation from the site is coordinated and appropriate
procedural steps are in place, the Flood Emergency Plan will be produced in
liaison with SGC, BCC and the EA. The main objectives of the Flood Emergency
Plan would be to provide:
• An Emergency Route Plan – showing the escape route in different
circumstances, when necessary and safe to do so;
• Location of Safe Refuge – the location of a safe refuge area should be
made clear to users of the site;
• Practical Flood Advice – lists of provisions that will be recommended as
well as the best way to respond before and during an event;
• Guidance on Education and Training – increase awareness regarding the
risk of flooding by preparing a poster to accompany this evacuation plan;
• Information on local Flood Warning Services – the development should be
linked to the Environment Agency’s Flood Warning Service; and
• Defined roles and responsibilities during a flood event – listing the roles
and responsibilities of who will need to action on flood warnings and other
tasks required to prepare for flood events.
Fluvial/Tidal Flood Risk - Offsite
14.5.48. As discussed above the offsite effect posed to third parties due to the volume of
floodwater displaced by raising part of the Proposed Development Site is
considered minor adverse during operation.
Surface Water Flood Risk (Onsite/Offsite)
14.5.49. Surface water runoff from the Proposed Development will be managed during the
operational phase through the use of SuDS techniques. The Level 3 FRA
provides an outline drainage strategy to ensure runoff rates from the Proposed
Development do not exceed pre-development greenfield runoff rates.
14.5.50. Surface water runoff generated within the Proposed Development will drain via a
positive drainage system to an attenuation feature (of approximate attenuation
volume of 3,800m3). This feature will attenuate surface water runoff from the
Generation Station Site to pre-development greenfield rates for rainfall events up
to and including the 1 in 100 year (inclusive of climate change).
14.5.51. The water attenuation feature will be located in the Utilises, Services and
Landscaping Area, as illustrated in Figure 3-1 Volume III of this PEI Report. The
most likely options are that it will comprise a single water body, either located on
the eastern part of the Proposed Development Site, forming the boundary with
the CCR Site, and/or a linear feature along the southern boundary of the CCR
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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Site adjacent to the PROW that is being proposed, as illustrated in Figure 3-1,
Volume III this PEI Report.
14.5.52. The outlet from the SuDS attenuation feature will discharge into the Red Rhine,
possibly via the Crook Marsh stream depending on the final location of the water
attenuation feature. Restricting the discharge rate to the pre-development rates
will ensure that flood risk posed to the Proposed Development and third party
land and property remains low.
14.5.53. The residual effect to the Proposed Development Site is considered to be minor
beneficial, whereas the residual effect to third party property and land is
considered to be negligible during operation.
Decommissioning Phase
14.5.54. The Proposed Development has a design life of approximately 30 years,
although the operational life may be extended beyond this, after which, the
station and associated infrastructure will be decommissioned. The
decommissioning phase is expected to be relatively short in duration, of the order
of approximately one year. Decommissioning will require appropriate method
statements and a demolition EMP to mitigate any adverse effects on surface and
groundwater receptors.
14.5.55. The potential for effects on the water quality attributes of nearby surface and
groundwater receptors will be similar to those identified for the construction
phase. Fuel and oils will be used by demolition machinery and the vehicles used
to remove waste materials from the site with the potential for pollution of surface
watercourses through spillage and/or leakage. There is also the potential for
crushed concrete and concrete dust to enter waterbodies either via windborne
dust or spillage of materials whilst in transit. However, these effects will be
temporary and localised, having a negligible effect on surface and groundwater
receptors.
14.5.56. The water supply pipeline will likely be capped at both ends and left in-situ. The
majority of other sub-surface structures are also likely to remain in in-situ,
therefore no significant effects on groundwater flow paths or groundwater
receptors are anticipated. Some minor re-profiling may be required once any
above ground structures have been removed, however no significant impacts or
effects groundwater receptors would be expected.
14.5.57. Taking into account the mitigation measures outlined for the construction phase,
which would be implemented during decommissioning, the residual effect is
considered to be negligible.
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14.6. Residual Effects
14.6.1. This section addresses all effects which cannot be eliminated through design
change or application of standard mitigation measures. An effect significance
level is attributed to residual effects that remain after prescribed mitigation
measures are taken into account. The main conclusions of this chapter are also
provided.
14.6.2. A summary of the significance level attributed to residual effects, which remain
after the application of prescribed mitigation measures is provided below.
14.6.3. The methodology adopted for this chapter (see Section 14.2) considers major or
moderate effects to be significant, and minor or negligible effects not to be
significant. As mentioned previously, it has been assumed that any construction
effects (short and medium term) are temporary and any operational effects (long
term) are permanent, unless otherwise stated.
Water Quantity and Quality
14.6.4. Table 14-8 indicates that during the enabling works and construction phase of the
Proposed Development, the effect significance attributed to residual effects
posed to water resources are all minor adverse. The exception to this is the
potential for contamination by oils, hydrocarbons and cement, which is
considered to be negligible following mitigation.
14.6.5. Incorporation of industry accepted construction methods will reduce the potential
for major pollution incidents to occur and thus further protect identified surface
water and groundwater receptors.
Table 14-8: Residual Effect Significance for Water Quantity and Quality during Construction
Phase (Temporary)
Potential Effect Importance of Receptor
Magnitude of Change (with mitigation)
Significance of Effect (Residual)
Water Quantity
Alteration to flow regime and hydro-morphology
Red Rhine (including Crook’s Marsh Stream) (High)
Low Minor Adverse
Alteration to flow regime and hydro-morphology
Stuppill Rhine (High) Low Minor Adverse
Alteration to flow regime and hydro-morphology
Tidal River Severn (Very High)
Neutral Minor Adverse
Alteration to shallow groundwater flow
Shallow Groundwater (high)
Low Minor Adverse
Water Quality
Increased sediment loading
Red Rhine (High) Low Minor Adverse
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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Potential Effect Importance of Receptor
Magnitude of Change (with mitigation)
Significance of Effect (Residual)
Increased sediment loading
Stuppill Rhine (High) Low Minor Adverse
Increased sediment loading
Tidal River Severn (Very High)
Neutral Minor Adverse
Contamination by oils, hydrocarbons and cement
Red Rhine (High) Low Minor Adverse
Contamination by oils, hydrocarbons and cement
Stuppill Rhine (High) Low Minor Adverse
Contamination by oils, hydrocarbons and cement
Tidal River Severn (Very High)
Neutral Minor Adverse
Contamination by oils, hydrocarbons and cement
Shallow Groundwater (High)
Low Minor Adverse
Contamination by oils, hydrocarbons and cement
Deeper Groundwater (High)
Neutral Negligible
Nutrient Enrichment Red Rhine (High) Low Minor Adverse
Nutrient Enrichment Tidal River Severn (Very High)
Neutral Minor Adverse
14.6.6. Table 14-9 indicates that during the operational phase of the Proposed
Development the effect significance level attributed to residual effects posed to
water resources are either negligible or minor adverse. In accordance with the
significance of effects methodology (see Section 14.2) negligible and minor
adverse effects are not considered to be significant.
Table 14-9: Residual Effect Significance for Water Quantity and Quality during Operation Phase
(Permanent)
Potential Effect Importance of Receptor
Magnitude of Change (with mitigation)
Significance of Effect (Residual)
Water Quantity
Alteration to flow regime and hydro-morphology
Red Rhine (including Crook’s Marsh Stream) (High)
Neutral Negligible
Alteration to flow regime and hydro-morphology
Stuppill Rhine (High) Neutral Negligible
Alteration to flow regime and hydro-morphology
Tidal River Severn (Very High)
Neutral Minor Adverse
Alteration to shallow Shallow Groundwater Low Minor Adverse
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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Potential Effect Importance of Receptor
Magnitude of Change (with mitigation)
Significance of Effect (Residual)
groundwater flow (high)
Water Quality
Increased sediment loading
Red Rhine (High) Neutral Negligible
Increased sediment loading
Tidal River Severn (Very High)
Neutral Minor Adverse
Increased sediment loading
Stuppill Rhine (High) Neutral Negligible
Contamination by oils, hydrocarbons and cement
Red Rhine (High) Neutral Negligible
Contamination by oils, hydrocarbons and cement
Tidal River Severn (Very High)
Neutral Minor Adverse
Contamination by oils, hydrocarbons and cement
Stuppill Rhine (High) Neutral Negligible
Contamination by oils, hydrocarbons and cement
Shallow Groundwater (High)
Neutral Negligible
Contamination by oils, hydrocarbons and cement
Deeper Groundwater (High)
Neutral Negligible
Nutrient Enrichment Red Rhine (High) Neutral Negligible
Nutrient Enrichment Tidal River Severn (Very High)
Neutral Minor Adverse
Nutrient Enrichment Stuppill Rhine (High) Neutral Negligible
14.6.7. On completion of the operational life of the Proposed Development, taking into
account the mitigation measures outlined above, the residual effect during
decommission considered to be negligible.
Flood Risk
14.6.8. The specific methodology for defining and assessing the significance of flood risk
as dictated by the requirements of the NPPF (Ref. 14-17) and Planning Practice
Guidance released in March 2014 (Ref. 14-18) is outlined in the FRA.
14.6.9. All flood risk receptors identified are classified as high importance receptors (i.e.
the Proposed Development Site and neighbouring third party property and land).
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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14.6.10. Table 14-10 and Table 14-11 provide a summary of the effect of the Proposed
Development on the risk posed by all flood sources to identified receptors during
the construction and operation phases respectively.
14.6.11. Table 14-10 indicates that the construction phase (with incorporated mitigation)
will have a negligible to major beneficial effect on the fluvial and tidal flood risk
posed to the Proposed Development. This effect range (from negligible to major
beneficial) depends on the timing of a potential fluvial/tidal event, for example
prior to ground raising, the construction phase will have a negligible effect on
flood risk, however post ground raising the construction phase will have a major
beneficial effect on flood risk by reducing flood risk from high to low.
14.6.12. Table 14-10 also indicates that the effect of the construction phase on other flood
sources, such as surface water, groundwater and artificial flood sources are
either negligible or minor adverse.
Table 14-10: Construction Phase Effect on Flood Risk (Temporary)
Potential Receptor Flood Pathway Effect on Flood Risk (with
mitigation)
Fluvial
Proposed Development Site (on-site)
Overtopping of Red Rhine
Negligible to Major Beneficial during construction
Third Party Property and Land (off-site)
Negligible to Minor Adverse during construction
Tidal (including residual risk)
Proposed Development Site (on-site) Overtopping/Breach of Coastal
Defences
Negligible to Major Beneficial during construction
Third Party Property and Land (off-site)
Negligible to Minor Adverse during construction
Surface Water
Proposed Development Site (on-site) Increase in Surface Water
Runoff Rates and Volumes
Minor Beneficial during construction
Third Party Property and Land (off-site)
Minor Adverse during construction
Groundwater
Proposed Development Site (on-site)
Groundwater raising above ground levels
Negligible to Minor Beneficial during construction
Third Party Property and Land (off-site)
Groundwater raising above ground levels
Negligible during construction
Artificial Sources
Proposed Development Site (on-site)
No Flood Source or Pathway
Negligible during construction
Third Party Property and Land (off-site)
Negligible during construction
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Table 14-11: Operation Phase Effect on Flood Risk (Permanent)
Potential Receptor Flood Pathway Effect on Flood Risk (with mitigation)
Fluvial
Proposed Development Site (on-site)
Overtopping of Red Rhine
Major Beneficial during Operation
Third Party Property and Land (off-site)
Minor Adverse during Operation
Tidal (including residual risk)
Proposed Development Site (on-site) Overtopping/Breach of Coastal
Defences
Major Beneficial during Operation
Third Party Property and Land (off-site)
Minor Adverse during Operation
Surface Water
Proposed Development Site (on-site) Increase in Surface Water
Runoff Rates and Volumes
Minor Beneficial during Operation
Third Party Property and Land (off-site)
Negligible during Operation
Groundwater
Proposed Development Site (on-site) Groundwater raising above
ground levels
Minor Beneficial during Operation
Third Party Property and Land (off-site)
Negligible during Operation
Artificial Sources
Proposed Development Site (on-site)
No Flood Source or Pathway
Negligible during Operation
Third Party Property and Land (off-site)
Negligible during Operation
14.6.13. Table 14-11 indicates that the operation phase (with incorporated mitigation) will
have a major beneficial effect on the fluvial and tidal flood risk posed to the
Proposed Development and Proposed Development Site due to raising site
levels above model flood levels.
14.6.14. The operation phase will have a negligible to minor adverse impact on the
fluvial/tidal risk posed to third party property and land.
14.6.15. Table 14-11 also indicates that the effects from the operation phase on other
flood sources (onsite and offsite), such as surface water, groundwater and
artificial flood sources are either negligible or minor adverse.
Conclusions
14.6.16. A number of potential effects (adverse and beneficial) on water resources have
been identified as a result of the construction (including enabling works),
operational and decommissioning phases of the Proposed Development. The
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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adopted assessment methodology considers moderate and major effects to be
significant, whereas minor or negligible effects not to be significant. The effect
significance level attributed to residual effects that remain after prescribed
mitigation measures are taken into account are outlined below:
• All residual effects posed to surface water and groundwater resources
during the construction phase (including enabling works) and operation
phase of the Proposed Development are either negligible or minor
adverse;
• No effects (beneficial or adverse) are deemed significant during the
construction (including enabling works) or operation phase, with no
adverse impact on WFD classifications of identified water resources;
• The raising of ground levels (above modelled flood levels) during the
construction phase will reduce the flood risk posed to the Proposed
Development to low, resulting in a major beneficial effect during both the
construction and operation phases of the development;
• Offsite the raising of ground levels (above modelled flood levels) during
the construction (and operation) phase will have a negligible to minor
adverse effect on the fluvial/tidal risk posed to third party property and
land;
• The construction phase and operational phase of the Proposed
Development will have a negligible effect on the risk posed by surface
water, groundwater and artificial flood sources to identified receptors.
14.7. Cumulative Effect Assessment
Overview
14.7.1. This section considers the cumulative impact of the Proposed Development and
associated infrastructure along with other consented schemes within the vicinity
on flood risk and surface and ground water receptors.
14.7.2. Consented and proposed schemes within the area which are considered
sufficiently close to give potential cumulative effects with the Proposed
Development have been identified and reviewed in terms of both the construction
and operational phase effects.
Construction Effects
14.7.3. During the construction phase the magnitude of cumulative effects and their
significance depends on the degree of which they overlap with each other.
14.7.4. Construction activities have the potential to create adverse effects on water
quality of local watercourses. Potential contamination of surface water runoff
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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thorough accidental spillages could, in turn, impact upon local water quality. An
increase in the mobilisation of sediments in surface water runoff may have an
adverse effect on local water quality.
14.7.5. The cumulative schemes sufficiently close to the Proposed Development Site or
Red Rhine to have the potential to lead to cumulative effects are the Severnside
Energy Recovery Centre, the new Spine Access Road, the realignment of the
Red Rhine, and Central Park, all of which are currently under construction and
should be operational by the start of construction of the Proposed Development.
Avon Power Station is also sufficiently close to the Proposed Development Site
to lead to cumulative effects, however it is not a consented scheme and therefore
there is no guarantee it will come forward; it will also be physically separated from
the Red Rhine by the Spine Access Road.
14.7.6. Regardless, where best practice construction methodologies are adopted
(including the EA’s full PPG measures) during the construction phase, the
likelihood of these pollution events occurring is minimised, or the consequences
of the potential effects are managed and reduced. A minor adverse cumulative
effect on water resources is anticipated during the construction and operation
phases of the cumulative schemes.
Land Raising
14.7.7. In addition to the Proposed Development a number of other consented schemes
have already undergone or require land raising to mitigate fluvial/tidal flood risk
over the developments lifetime. Modelling undertaken to inform the Level 3 FRA
has been used to understand the volume of floodwater displaced by each of the
consented schemes during selected fluvial flood event and tidal breach
scenarios.
14.7.8. The land raising associated with the Central Park scheme is considered likely to
result in a moderate adverse effect on flood levels during an extreme tidal flood
event, regardless of the contribution associated with the Proposed Development.
The Hold the Line policy proposed within the Severn Estuary Shoreline
Management Plan 2 (Ref. 14-19)) reduces the likelihood of this moderate
adverse effect occurring to low.
14.7.9. The land raising associated with the Proposed Development is predicted to make
a negligible contribution to this significant cumulative effect and therefore the
Proposed Development has been assessed as non-significant. A substantial
amount of the land raising considered as part of this cumulative assessment has
already been completed (i.e. majority of the Central Park Site) and therefore
could be soon considered as the current baseline. This may require an
amendment to the assessment for the final ES.
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Impermeable Area
14.7.10. An increase in impermeable area due to development of consented schemes is
likely, as a large percentage of the local area to be developed is currently
undeveloped permeable or greenfield land.
14.7.11. Unmitigated, the increase in surface water runoff rates and volumes due to an
increase in impermeable area would have an adverse cumulative effect on the
hydrological characteristics of the Red Rhine catchment area.
14.7.12. However, in accordance with NPPF (Ref. 14-17), the Proposed Development will
include SuDS to ensure surface water runoff rates post development do not
increase, through the use of attenuation or infiltration techniques. Therefore, the
cumulative effects associated with the increase in impermeable is likely to be
negligible.
Operational and Decommissioning Effects
14.7.13. No additional cumulative effects are assessed for flood risk and water resources
during the operational phase, as it is expected that all developments will have
addressed any related issues during the construction phase. During the operation
phase the cumulative schemes will be required to operate in compliance with the
conditions of its planning consent and /or environment permits.
14.7.14. It is not expected that there would be any cumulative effects during
decommissioning, given the negligible effect predicted for the proposed
Development and different design lives for the cumulative schemes.
14.8. Impacts and Effects yet to be Determined
14.8.1. It is recognised that the Site baseline conditions may change between the
preparation of this PEI Report and the final ES, as outlined in Chapter 7:
Assessment Methodology. The Proposed Development Site is currently subject
to excavation, top soil stripping, and levelling in certain areas in order for third
parties to deliver the Spine Access Road and new channel for the Red Rhine,
which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7:
Assessment Methodology. A haul road is also being constructed through the
middle of the Proposed Development Site to enable access by third party from
the roundabout to the east of the Site to the Severnside Energy Recovery Centre
to the west. These works onsite are being undertaken by other developers, under
extant planning permissions and are separate to the Proposed Development.
14.8.2. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changed
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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14.8.3. In particular, depending on the stage of works on Central Park, it may be
necessary to incorporate the new site levels on this cumulative scheme within the
baseline scenario, rather than continuing to consider it as part of a future
baseline or as a cumulative effect.
14.8.4. While the baseline conditions may change, and this may require the text in the
final ES to be updated, it is not anticipated that this would affect the assessment
or conclusions presented in this chapter and FRA.
14.8.5. A framework strategy for the Drainage Management Plan will be included as part
of the submission of the DCO.
14.9. References
Ref. 14-1 URS (February, 2013) Seabank3 EIA Scoping Report. Prepared for:
SSE Seabank Land Investments Ltd.
Ref. 14-2 The Planning Inspectorate (March, 2013) Scoping Opinion for
Proposed Seabank3 CCGT.
Ref. 14-3 Environment Agency Groundwater Vulnerability Map of the Southern
Cotswolds (Sheet 37), 1:100,000 Scale.
Ref. 14-4 Ordnance Survey (OS) Landranger Map, Bristol and Bath (Sheet
172), 1:50,000 Scale.
Ref. 14-5 Capita Symonds (March 2011) Avonmouth / Severnside Level 2
Strategic Flood Risk Assessment. Prepared for Bristol City Council,
South Gloucestershire, Lower Severn Drainage Board.
Ref. 14-6 Environment Agency (December 2009) Severn Tidal Tributaries
Catchment Flood Management Plan. Available at: www.environment-
agency.gov.uk [Accessed 8th May 2013].
Ref. 14-7 Landmark Group Limited (September 2012) Envirocheck Report,
centred on NSIP Development.
Ref. 14-8 Environment Agency (2009) Severn River Basin Management Plan.
Available at: www.environment-agency.gov.uk [Accessed 9th May
2013].
Ref. 14-9 Environment Agency (2013) Groundwater Aquifer Designation Map.
Available at: www.environment-agency.gov.uk [Accessed 10th May
2013].
Ref. 14-10 Environment Agency (2013) Groundwater Source Protection Zone
Map. Available at: www.environment-agency.gov.uk [Accessed 7th
May 2013].
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PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources
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Ref. 14-11 Environment Agency (2013) Flood Map. Available at:
www.environment-agency.gov.uk [Accessed 7th May 2013].
Ref. 14-12 Environment Agency (2013) Map of Flood Risk from Reservoirs
Available at: www.environment-agency.gov.uk [Accessed 7th May
2013].
Ref. 14-13 Directive 2000/60/EC of the European Parliament and of the Council
establishing a framework for the community action in the field of
water.
Ref. 14-14 UK Technical Advisory Group Water Framework Directive Site,
Available at: http://www.wfduk.org/ [Accessed 25th June].
Ref. 14-15 Department for Transport (DfT), (2003); The Water Environment Sub-
Objective Transport Analysis Guidance (TAG) Unit 3.3.11, Available
at: http://www.dft.gov.uk/webtag/documents/expert/pdf/unit3.3.11.pdf
[Accessed 10th May 2013].
Ref. 14-16 Highways Agency (2009); Design Manual for Roads and Bridges Vol.
11 Environmental Assessment. Section 3 Environmental Assessment
Techniques. Part 10 Road Drainage and the Water Environment. The
Stationary Office (TSO).
Ref. 14-17 Department for Communities and Local Government (DCLG), (2012);
National Planning Policy Framework, Communities and Local
Government Publications.
Ref. 14-18 DCLG (2014); Planning Practice Guidance – Flood Risk and Coastal
Change, Communities and Local Government Publications.
Ref. 14-19 Environment Agency (2010) Shoreline Management Plan 2.
Seabank 3
PEI Report – Chapter 15 Archaeology and Cultural Heritage
15. Archaeology and Cultural Heritage
15.1. Introduction 15.1.1. This chapter identifies the location, type and significance of cultural heritage
assets and their setting within the DCO Site and surrounds, as well as providing an assessment of the effects of the Proposed Development on these assets and settings.
15.1.2. Heritage assets are defined as “a building, monument, site, place, area or landscape identified as having a degree of significance meriting consideration in planning decisions, because of its heritage interest’” (Ref. 15-1). Heritage assets include assets that are both designated under legislation and non-designated. The latter are mainly, but not limited to, assets identified by local planning authorities as having a degree of local interest or significance and are usually recognised by their inclusion within the local Historic Environment Record (HER) (Ref. 15-2).
15.1.3. The specific aims of the assessment reported herein are to:
• Identify and characterise designated and non-designated assets, both within the DCO Site and the defined study area;
• Assess the significance and setting of those assets;
• Identify areas disturbed by modern activity that might have affected the survival and significance of heritage assets;
• Assess the impact of the regeneration scheme on the significance and setting of heritage assets within the study area; and
• Outline strategies to mitigate any identified impact arising from the proposals upon heritage assets.
15.1.4. The assessment has been carried out in accordance with the Institute for Archaeologists (Ref. 15-3) Code of Conduct and their Standards and Guidelines and in accordance with policy and guidance, with specific reference to:
• Policies within the NPPF (Ref. 15-1);
• English Heritage ‘Conservation Principles Policy and Guidance’ (Ref. 15-4); and
• English Heritage ‘The Setting of Heritage Assets’ (Ref. 15-5).
May 2014 Page 15-1
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Consultation 15.1.5. A scoping request was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on the proposed structure, methodology and content of this chapter. A summary of stakeholder comments and how they have been incorporated into this PEI Report chapter are provided in Table 15-1.
Table 15-1: Scoping Opinion Responses Relevant to Archaeology and Cultural Heritage
Stakeholder Comment Addressed within the Report
Planning Inspectorate
Relevant receptors should include those identified by English Heritage, together with others identified in consultation with BCC and SGC
See section 15.2 of this chapter
English Heritage
This development could, potentially, have an impact upon a number of designated heritage assets and their settings in the area around the site and the ES should contain a thorough assessment of the likely effects, which the proposed development might have upon those elements, which contribute to the significance of these assets. Known heritage assets within close range of the proposed development include Kingweston House and its Historic Park, as well as the Grade II* listed-Bishops Farmhouse, Berwich Lane, Almondsbury.
Noted. These have been included in sections 15.3 and section 15.5 of this chapter
The ES should consider the potential impacts upon those heritage assets which are not designated.
See section 15.5 of this chapter.
A staged programme of archaeological investigations will be required before the potential impact of the scheme can be fully appraised, including geophysical and geotechnical surveys.
See section 15.5 of this chapter.
The proposed pipeline between Seabank 3 and Bristol WWTW will require mitigation.
See section 15.5 of this chapter.
A historic buildings assessment should be included to fully assess the impact on heritage assets that are designated listed buildings or conservation areas.
See section 15.3 of this chapter.
SGC The assessment should take into account the changing relief and the openness of the landscape which is such that some grade II heritage assets (which are by definition of national importance by virtue of their inclusion on the national list) may suffer greater impacts than other closer heritage assets that experience less visual impact by virtue of changing topography or other buildings and landscape features.
See sections 15.2, 15.3 and 15.5 of this chapter.
The EIA should make reference to the settings or direct impacts on undesignated heritage assets as well as on designated ones, in order to satisfy policy requirements.
See sections 15.3 and 15.5 of this chapter.
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Stakeholder Comment Addressed within the Report
A combination of electro- magnetic and caesium vapour geophysical surveys should be undertaken as soon as possible in order to try to clarify potential for surviving archaeological deposits to occur within the affected areas of the site and within the area of search for the proposed cooling water pipeline.
See section 15.3 of this chapter.
The ES should refer to the NPPF or the 1990 Planning (Listed buildings and conservation areas) Act or any English Heritage guidance on the assessment of significance and setting for heritage assets.
See Appendix D, Volume II of this PEI Report
BCC Any works to provide connections from Seabank 1 & 2 to the proposed Seabank 3 must be fully considered.
See section 15.3 of this chapter.
Further details and satisfactory mitigation should be put forward regarding the proposed pipeline connection to the Bristol WWTW.
See section 15.5 of this chapter.
15.1.6. Following the receipt of the Scoping Opinion, consultation has been on-going
with the County Archaeologists for SGC and BCC, as well as English Heritage, and is referred to throughout this chapter. The consultation was also used to identify if any of the mitigation proposals put forward had been carried out as part of any other development schemes in the area.
Legislation and Planning Policy Context 15.1.7. A summary of the planning policy relevant to this chapter and the Proposed
Development is presented in Appendix D, Volume II of this PEI Report.
15.1.8. In terms of relevant legislation, the Planning (Listed Buildings and Conservation Areas) Act 1990 (Ref. 15-6) establishes a requirement to have special regard to the desirability of preserving the setting of a listed building or conservation area.
15.2. Assessment Methodology and Significance Criteria 15.2.1. This assessment methodology has been informed by the Archaeology and
Development in the North Avon levels Guidance Note (Ref. 15-7) which details SGC’s approach to the conservation and protection of the archaeological heritage and recommends strategies for assessment.
15.2.2. The assessment has also been informed by a number of previous investigations listed in the baseline section.
15.2.3. This research has been augmented by a site walkover undertaken by an archaeological and built heritage consultant. The purpose of the site visit was to verify the current ground conditions and identify any areas of recent ground disturbance which would have the potential to remove below-ground deposits.
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The site visit was also used to visit the identified designated heritage assets and any non-designated heritage assets which may be physically impacted by the Proposed Development, and to identify their setting.
Study Areas
The Proposed Development
15.2.4. A 1km inner study area has been used to identify designated and non-designated assets which have the potential to be affected by the development proposals within the Proposed Development Site. This inner study area was defined by the limited potential for impacts upon the setting of assets beyond this point. This area is considered to be sufficient to accurately represent the archaeological and architectural character of the immediate area.
15.2.5. Due to the potential for impact upon listed buildings, a secondary study area of 2km was initially considered, but due to no listed buildings being present within this radius it has not been considered further in this assessment.
15.2.6. All designated assets within a 5km outer study area were assessed. A Zone of Theoretical Visibility (ZTV) to a distance of 10km from the Proposed Development was also assessed to determine the presence of designated assets within the ZTV, as illustrated in Figure 15-1 (Volume III of this PEI Report).
Associated Infrastructure
15.2.7. The proposed cooling water pipeline will be located within a predominantly 30m wide corridor, running predominantly adjacent to the existing cooling water pipelines that serve Seabank 1 & 2. The land through which these existing pipelines pass has already been archaeologically assessed (Ref. 15-8).
15.2.8. The study area for the proposed cooling water pipeline is a 500m radius from the ‘Other DCO Land’ within which it resides. This was considered adequate to determine the effects of the proposed pipeline and was agreed in liaison with English Heritage, SGC and BCC.
15.2.9. The proposed electrical connection runs through (or under) the existing Seabank 1 & 2 site on previously disturbed land and is therefore not assessed further in this chapter. It has been assumed that there are no archaeological remains beneath this part of Seabank 1 & 2 that would be affected by the cables, and given they would be located underground or in cable racks up to 2m high the visual effect on the settings of heritage assets in the surrounding area is considered to be imperceptible.
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Impact Assessment and Significance Criteria 15.2.10. This assessment takes into account the significance (importance) of each asset,
and the likely impact (without mitigation) of the Proposed Development upon them, in order to appraise the potential effects. Only those heritage assets where there is a potential for effects have been included within this assessment.
15.2.11. For the purposes of this assessment, the term ‘significance’ is that as defined in Annex 2 of the NPPF (significance for heritage policy) (Ref. 15-1). In this context significance is defined as the value of the heritage asset arising from heritage interest, which may be archaeological, architectural, artistic, or historic. Significance can also be derived from an asset’s setting. Taking these criteria into account, each identified heritage asset can be assigned a level of significance in accordance with a five-point scale, as shown in Table 15-2.
15.2.12. Having identified the importance of the heritage assets, the next stage is to assess the level or magnitude of the change, or impact, from the development. Impacts can be considered in terms of direct, indirect and cumulative. The sources of impact may arise during construction, operation and/or decommissioning, and can be characterised in terms of timing, scale, duration, reversibility and the likelihood of the impact occurring and can be beneficial or adverse.
Table 15-2: Criteria for Establishing the Importance of Heritage Assets Sensitivity (significance) of the Receptor
Criteria
Very High Remains of inscribed international importance, such as World Heritage Sites. Grade I and Grade II* Listed Buildings. Grade I and Grade II* Registered Parks and Gardens. Scheduled Monuments. Registered battlefields Non-designated archaeological assets of schedulable quality and importance. Non-designated buildings, monuments, sites or landscapes that can be shown to have particularly important qualities in their fabric or historical association.
High Grade II listed Buildings. Conservation Areas. Grade II Registered Parks. Assets of high archaeological resource value as identified through consultation.
Medium Locally listed buildings as recorded on a local authority list Non-designated buildings, monuments, sites or landscapes that can be shown to have important qualities in their fabric or historical association. Historic Townscapes with historic integrity in that the assets that constitute their make-up are clearly legible
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Sensitivity (significance) of the Receptor
Criteria
Low Non-designated buildings, monuments, sites or landscapes of local importance and of modest quality Locally important historic or archaeological assets, assets with a local value for education or cultural appreciation and of medium archaeological resource rating, Assets that are so badly damaged that too little remains to justify inclusion into a higher grade, Parks and gardens of local interest.
Very Low Assets identified as being of no historic, evidential, aesthetic or communal interest. Assets whose values are compromised by poor preservation or survival or of contextual associations to justify inclusion into a higher grade.
15.2.13. The assessment of impact includes the consideration of an asset’s setting, whether designated or not. The setting of a heritage asset varies from case to case and cannot be generically defined. Setting contributes to the significance of an asset, and should not be considered separate from it. English Heritage guidance is that an assessment of the impact of a proposed development should identify whether the development would be acceptable in terms of the degree of harm to an asset’s setting. Fundamental to the assessment of impacts on setting is the principle that a visual relationship may contribute to setting, but does not define it.
15.2.14. The magnitude of a change can be judged on a five-point scale, as shown in Table 15-3. The impact score is arrived at without reference to the importance of the asset and the change is assessed without taking into account any subsequent mitigation proposals.
Table 15-3: Criteria for Establishing the Magnitude of Change on a Cultural Heritage Asset Impact Rating Description of Impact High Change such that the significance of the asset is totally altered or destroyed.
Comprehensive change to setting affecting significance, resulting in changes in our ability to understand and appreciate the resource and its historical context and setting.
Medium Change such that the significance of the asset is affected; or Changes such that the setting of the asset is noticeably different, affecting significance resulting in changes in our ability to understand and appreciate the resource and its historical context and setting.
Low Change such that the significance of the asset is slightly affected; or Changes to the setting that have a slight impact on significance resulting in changes in our ability to understand and appreciate the resource and its historical context and setting.
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Impact Rating Description of Impact Minimal Changes to the asset that hardly affect significance; or
Changes to the setting of an asset that have little effect on significance and no real change in our ability to understand and appreciate the resource and its historical context and setting.
No change The development does not affect the significance of the asset; or Changes to the setting do not affect the significance of the asset or our appreciation of it.
15.2.15. The initial assessment of the significance of effect is undertaken at this stage of the process. The only mitigation which is taken into account at this stage is any mitigation measures incorporated into the design. No additional mitigation such as excavation or recording is taken into account at this stage. It should be recognised that some environmental mitigation measures, for example landscaping or areas of ecological compensation, can themselves be a source of impact.
15.2.16. The final and concluding assessment of the level of overall significance of the effect takes into consideration additional mitigation such as archaeological excavation or building recording. The statement of the residual effect is arrived at by cross-referencing between the importance of the asset (Table 15-2) and the magnitude of change (Table 15-3), as shown in Table 15-4. The assessment of the overall significance of effect of the scheme on each identified heritage asset can be negligible, adverse or beneficial. Effects are only considered to be significant if they are major or moderate.
Table 15-4: Matrix for Establishing Overall Significance of Effect
Importance of Asset
Magnitude of Change No Change Minimal Low Medium High
Very High
Negligible Minor Major Major Major
High
Negligible Minor Moderate Major Major
Medium Negligible Minor Minor Moderate Major
Low Negligible Negligible Minor Minor Moderate
Very Low Negligible Negligible Negligible Negligible Negligible
Uncertain Determinable only on definition of the asset
15.2.17. Within national planning policy, principally the NPS and NPPF, effects are considered in terms of ‘substantial’ or ‘less than substantial’ harm. Paragraph 132
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of the NPPF states that substantial harm to a designated asset should be wholly exceptional and, in accordance with paragraph 133, weighed against the public benefit of the scheme.
15.2.18. The NPPF does not provide a qualitative definition of what constitutes ‘substantial’ or ‘less than substantial’ harm. The assessment is required to report on the significance of an effect and does not make a judgement on whether ‘substantial’ or ‘less than substantial’ harm will be caused. The judgement of whether an effect causes ‘substantial’ harm is based on whether the effect on the individual asset has an impact on the wider historic environment; i.e. where the significance of an asset is such that its loss would be detrimental to the understanding of the unique values of the wider asset type. This may include extensive physical damage to an asset or loss of critical elements of an asset’s setting. The identification of ‘substantial’ harm is therefore one of professional judgment and not directly equitable to the significance of the effect.
Key Parameters for Assessment 15.2.19. The variation in building dimensions presented in Chapter 4: Project Description
under the Rochdale Envelope principle is an important consideration for this PEI Report.
15.2.20. However, regardless of the difference in presented maximum and minimum parameters it is assumed that the majority of the main works area will be cleared of vegetation and topsoil, no matter what the final sizing and layout of the buildings are. The Rochdale Envelope parameters do not, therefore, significantly affect the approach utilised in either the archaeological or cultural heritage assessments, and consequently the outcome of these assessments will not vary. Therefore, no further discussion of the Rochdale Envelope parameters is provided in this chapter.
15.4. Baseline Conditions
Previous Archaeological Investigations 15.3.1. Archaeological investigations within the study area for the Proposed
Development Site and associated infrastructure have been assessed and are fully listed in Appendix H (Part 1), Volume II of this PEI Report, and their locations illustrated on Figure 15-2 (Volume III of this PEI Report) for the Proposed Development Site and Figure 15-3a and Figure 15-3b (Volume III of this PEI Report) for the associated infrastructure.
15.3.2. The assessment has also been informed by a number of previous archaeological and geotechnical investigations described in this section and illustrated in Figure 15-4, Figure 15-5, and Figure 15-6 in Volume III of this PEI Report.
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The Proposed Development Site
15.3.3. A number of investigations have taken place within the Proposed Development Site, in the Seabank 1 & 2 site, and in close proximity to the proposed cooling water pipeline. What follows is a description of the most relevant investigations that have been undertaken, either within or in very close proximity to the Proposed Development Site and proposed cooling water pipeline corridor.
15.3.4. An excavation took place within the Proposed Development Site as a result of discoveries during watching brief monitoring during the laying of the existing gas pipeline that extends through the Proposed Development Site (known as the Abson pipeline) (Event No 11055 14313/3, Field 158 (Ref. 15-10; Ref. 15-11, Ref. 15-27). The watching brief revealed a well preserved buried land horizon at 6.62m AOD). A buried topsoil was sampled and carbon dated to 2140-1740 Calibrated BC. Pollen analysis revealed a high quantity of fern spores probably indicating the lower horizons of a terrestrial soil. Diatom analysis showed poor preservation but noted that both brackish and freshwater taxa were present. Three separate alluvial layers, 0.4m, 0.5m and 1.2m thick overlaid the buried topsoil. Of archaeological significance, the watching brief revealed two ditches (Ditches 19 and 37, as shown on Figure 15-4 (Volume III)), the fills of which contained late-3rd to mid-4th Century AD pottery and fragments of quern stone. A bone spindle whorl was also found. Several thin alluvial layers sealed the ditch fills. The upper alluvial layers also contained pottery of a similar date.
15.3.5. A pit or ditch terminus was also revealed (Ditch 42) together with a further truncated ditch orientated east to west. Fills of both features also contained pottery of 3rd to 4th Century AD date.
15.3.6. A Ridge and Furrow Cultivation (2) is located within the northern part of the Proposed Development Site, referred to as New Pill Gout Chitterling Gout, Pilning (SGSMR18999).
15.3.7. The evidence revealed in the excavation suggests the presence of a settlement of 3rd to 5th century date being present in the vicinity. The evidence corresponds closely with data retrieved for excavations at Crook’s Marsh Farm (Ref. 15-12).
15.3.8. A few hundred metres to the southeast of the Generating Station Site, and within the CCR Site, a mettled trackway, Romano British ditch, and medieval ridge and furrow was revealed during a watching brief in 1997 (Event no 12759) (Ref. 15-13). To the west of the Generating Station Site, a desk top study (Event no 19090) of the area for the proposed Severnside Energy Recovery Centre was undertaken in 2009. Much of the area had been developed during the 1960’s, but areas to the north had suffered less damage and had archaeological potential.
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15.3.9. A barrage balloon anchor (SGSMR19088 and associated huts (SGSMR 19088) were recorded in the study area. The archaeological fieldwork identified a consistent alluvial sequence within all the evaluation trenches. Organic strata, observed within the boreholes, and interpreted as saltmarsh deposits were seen in evaluation trenches 3, 4 and 6 sloping downwards towards the west. These sediments are interpreted as being representative of mud flats that were only occasionally inundated by tidal waters, thereby allowing plant communities to develop.
15.3.10. The stone footings and concrete floor surface of a post-medieval building were identified within trench 5, 10m to the west of an in-filled boundary ditch. Both the building and the ditch are depicted on the 1881 1st Edition OS map. No datable material indicative of the construction date of the structure was recovered from the foundation trenches of the building, but material broadly dated from the late 18th and 19th century was recovered from bedding material for a floor surface, demolition and abandonment deposits.
15.3.11. An archaeological evaluation was undertaken by Cotswold Archaeology in August 2010 and to the northwest of the Generating Station Site (Event no 21030). Five trenches were excavated revealing a consistent sequence of alluvial deposits which contained inorganic material between 2.9m and 5.65m AOD. The stone footings of a post medieval building were also revealed within trench 5.
15.3.12. Two trenches were excavated immediately to the northwest of the Generating Station Site, to the north of the Red Rhine. The identified geological deposits comprised alluvium overlying the Wentlooge Formation. A Roman ditch and pit were present in one trench and could be seen to survive from within 0.5m of the present ground level. Parallel to and approximately 4m away from the Roman ditch was a post medieval ditch. An organic deposit at the top of the Wenlooge Formation was recorded in both trenches at 4.1m and 4.3m AOD respectively.
Other DCO Land
15.3.13. In terms of the associated infrastructure there have been a number of investigations along the route of the current cooling water pipeline servicing Seabank 1 & 2, which the proposed water pipeline shall follow. A Desk Study (Event no 20076, (Ref. 15-14) for land close to the northern end of the pipeline route noted that the study area for the assessment lay close to a Second- to Fourth-century site at Crook's Marsh Farm, which was excavated in the late 1970s. The site itself was adjacent to the site of Worthy Farm which was in existence by the 13th Century. Ridge and Furrow also covered the land within the study area. Two trenches were excavated, one at a right-angle to the longer trench and beginning midway along it. No archaeological features or finds were recorded (Event no 20077). Event no 20761 is evidence from the Ordnance
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Survey first edition 1:2500 plan (Gloucester Sheet LXXI.10) which records Chittening Farm on the eastern side of Severn Road.
15.3.14. Chittening Stream runs parallel with Severn Road on its east side. Between April and May 2007 an archaeological excavation was carried out at the site of Washingpool Farm, Chittening Road, Severnside by Bristol and Region Archaeological Services (BaRAS (Event No 24536)). A single trench, measuring 20m long by 4m wide was excavated at Event no 20021. Elements of Washingpool Farm (2172M) were found at the south end of the trench, including a mortared stone wall and cobbled areas. All dated to the post-medieval period. A large pond feature of early nineteenth-century date was also recorded. The trench was excavated to a maximum depth of 2m below the ground surface (4.6m AOD).
15.3.15. A desk study at Estuary Industrial Estate, Chittening Road, Avonmouth (Event no 24616) identified that the Estuary Industrial Estate was agricultural land in low lying salt marsh until post-medieval development. The area was bisected by a local routeway (possibly a drove) named on later plans as Washingpool Lane. Green Splot Farm (2170M) was established at the southern end of the Estuary Industrial Estate between 1773 and 1830. During the First World War the adjacent site was developed as a munitions factory (2750M) complete with its own rail infrastructure. Two storage buildings associated with this facility are depicted on part of the Estuary Industrial Estate on a plan of the site dated 1918. During the 1950s the former munitions factory was adapted for light industrial use and a secondary phase of rail infrastructure was added. Chittening Road was first depicted on the OS plan of 1949 and by 1969 Green Splott Farm and Washingpool Lane had been replaced on the site by industrial warehousing.
15.3.16. In 1996, BaRAS undertook a desk based assessment and excavation for the route of the existing cooling water pipelines serving Seabank 1 & 2 (Event no 20079). The study concluded that the pipeline would affect only one known archaeological site, Washingpool Farm. Other elements of the historic landscape, particularly fields with surviving ridge and furrow, hedges and drainage ditches, were also identified as being affected. It was suggested by the authors that the site of Washingpool Farm be archaeologically evaluated, and that an archaeological watching brief be carried out during the excavation of the pipeline include a programme of palaeoenvironmental sampling. The watching brief in 2008 on geotechnical pits for the extant pipeline recorded only one pit and no further archaeological features (Event no 20080).
15.3.17. The watching brief on the installation of the existing cooling water pipelines (Event 20832) took place between March and June 1997. The watching brief was maintained during construction of the water pipeline between Bristol WWTW and
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the Seabank 1 & 2 station by Bristol and Region Archaeological Services (Ref. 15-15; Ref. 15-16).
15.3.18. The pipeline route was excavated by 360 degree tracked excavator except where it crossed fixed infrastructure, roads or railway line when directional drilling was used. No archaeological features and few finds were observed during the work. However, several significant geoarchaeological observations were made.
15.3.19. On the first section of the pipeline, between ST 5337 7966 and ST 5346 7987, a thin dark-brown organic soil was observed at a depth of 0.31m AOD below the ground surface. It was suggested that the layer may have represented "a buried former topsoil." At ST 5339 8023 on the second section an horizon of dark-brownish clay 0.06m thick and containing organic material was observed at 4.7m AOD. This returned a radiocarbon date of 3930 +/- 50 BP (Wk 5804) giving a date of 2580-2290 Cal BC (to a 2-sigma confidence using Oxcal).
15.3.20. A similar band of organic clay exposed at location ST 5347 7986 was identified at 4.65m AOD. The excavation of the segment of the route alongside the railway exposed a thin layer of dark-grey organic clay at ST 5316 8080. This was at an elevation of 4.325m AOD. This context was noted intermittently along this section of the pipeline trench.
15.3.21. At ST 5344 8058 a further lens of clay 0.05m thick and at an elevation of 4.95m AOD was sampled for radiocarbon dating. This produced a date of 4780 +/- 90 BP (Wk 5805), 3780-3360 BC at a 2-sigma calibration.
15.3.22. A further organic clay horizon was exposed at location ST 5349 8050. This was at an elevation of 5.04m AOD and yielded a radiocarbon date of 3920 +/- 60 BP (Wk 5806), which was calibrated to give a date of 2580-2200 BC.
15.3.23. During monitoring of the pipeline segment from Rockingham to the Sevalco factory on Chittening Road, a dark-grey organic clay 0.02m thick was observed at location ST 5327 8129. It was at an elevation of 4.05m AOD. Palaoenvironmental analysis of the samples of the clays, including wet-sieving produced no visible organic remains. The samples were also subject to loss on ignition tests which indicated that the organic content ranged between 6.8% and 7.16%. It was noted that the radiocarbon dates obtained from the samples fell within the broad range c.3500-2000 Calibrated (Cal) BC which had been established for deposits at similar elevations during work elsewhere in the North Avon Levels. The archive for the work was deposited with Bristol Museum and Art Gallery under the accession number BRSMG CMAG 1997.0021.
15.3.24. In 2009, four archaeological trenches and eight trial pits were excavated at Smoke Lane (Event 20955). These trenches revealed a sequence of alluvial deposits including an organic clay silt at a depth of 2.3m and 2.55m below the
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present ground surface. A sample from this deposit produced a radiocarbon date with a calibrated date range between 2580 BC and 2190 BC, with a 65.8% probability of dating between 2470 BC and 2280 BC. No artefactual remains were recovered from this deposit.
15.3.25. In trench 1, a large ditch that was visible as a surface depression was recorded. This feature was cut through the upper layers of alluvial deposits and no finds were recovered from the fill. The evaluation recorded no other archaeologically significant material. A desk assessment undertaken in advance of construction of the fire service training centre (Event no 20912) revealed evidence for ridge and furrow of possible medieval date within the study area. This was recorded by an air photograph of 1941 and the site itself was never developed.
15.3.26. A geophysical survey was undertaken by Stratascan on the south side of Smoke Lane in 2001. The survey covered 2.7ha undeveloped grassland (Event no 20937). Several anomalies were recorded, some associated with modern features including pipeline and fence lines. The survey also identified probable remnants of ridge and furrow across much of the site as well as two possible palaeochannels roughly in its centre (Ref. 15-17). A desk study undertaken by GGAT in the area of the proposed pipeline in 1995 (Event no 20056) argued that the landscape in the general area is of medieval or post-medieval origin but that within the study area "the cumulative effects of past development have covered or removed virtually all traces of the pre-20th century landscape within the Merebank/Lakeside area". Two known archaeological sites were identified: Madam House Farm and the Mere Bank. It was suggested that the area should be subject to archaeological evaluation to identify any buried archaeological sites.
Geophysical Survey 2013
15.3.27. A Ground conductivity survey was undertaken by Terradat in May 2013 and the results are presented in Figure 15-7a (Volume III of this PEI Report); Figure 15-7b (Volume III) and Figure 15-7c (Volume III) present the geophysical results overlaid with the single-shaft layout and the multi-shaft layout respectively. The investigation was carried out using caesium vapour magnetometery and electromagnetic ground conductivity surveying techniques. This is in accordance with the scoping response made by SGC.
15.3.28. The general survey objectives are detailed below:
• To investigate the archaeological potential of the Generating Station site;
• To investigate the palaeo-environmental potential of the Generating Station site; and
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• To assess the presence /absence of potential archaeological anomalies that might be present.
15.3.29. The survey indicated the presence of a small zone of low conductivity correlating with a topographically raised area forming a small island feature. The area northwest of Minors Lane is mainly characterised by a network of major drainage ditches associated with a central, broadly north-south orientated, double-ditch feature, probably representing an old trackway. The fields delimited by this network of ditches have ridge and furrow, cut by minor drainage ditches. No certain pre-ridge and furrow archaeological features have been detected, although some possible features were tentatively identified along the northern margin of the ‘island’. The strong magnetic anomalies associated with the pipelines preclude identification of the line of the early ditches observed during their construction – a problem further compounded by the similar alignment of the Roman ditches and the ridge and furrow in many cases.
15.3.30. Broad features in the magnetic data (and to a lesser extent the conductivity data) provided some evidence for early sedimentary features, possibly palaeo-channels, which are orientated roughly east-west on the north side of the island (GPW4-GPW2) but swing around it to be orientated northwest-southeast in GPW3. Evidence for the palaeo-channels southeast of the modern road is slight, and the broad variations of conductivity in this area may be more a product of the modern topography.
Archaeological Monitoring of Geotechnical Survey
15.3.31. Archaeological monitoring of ten California Bearing Ratio (CBR) testing was undertaken by URS in October 2013 in accordance with a specification prepared by URS in consultation with David Haigh, the Archaeological Advisor to SGC and Vanessa Straker, the Regional Scientific Advisor at English Heritage. The monitoring was required to observe any physical potential for archaeological or palaeoenvironemental remains present in the location of the Geotechnical Investigation (GI). The results are presented in a brief report in Appendix H (Part 2), Volume II of this PEI Report.
15.3.32. The location of each investigation was marked by the geotechnical contractor and an area approximately 1m2 excavated by hand to a depth of 0.2-0.3m below current ground level and are illustrated in Figure 15-8 (Volume III of this PEI Report). The pits were excavated under direct archaeological supervision, in level spits, until either the top of the first archaeological horizon or undisturbed natural deposits are encountered. The resulting surface was inspected for archaeological remains and cleaned if necessary and practicable.
15.3.33. Only two Geotechnical Investigation (GI) pits contained evidence of archaeological remains. CBR001 contained a possible reworked plough soil
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containing pottery of likely Romano British date. CBR007 was located on a low visible mound towards the southern central edge of the Generating Station Site, near the southern perimeter of the centre of the Proposed Development Site. The mound was also identified by the geophysical survey, as shown in Figure 15-7a (Volume III of this PEI Report). The GI pit contained evidence of a reworked plough soil which contained three shards of pottery of late medieval date and several large pieces of unworked limestone. The combined evidence suggests the presence of a possible house platform of later medieval date.
15.3.34. A geotechnical transect from the 2013 investigation is presented in Figure 15-9 (Volume III of this PEI Report).
Historic Environment Assets
15.3.35. No designated archaeological assets have been identified within the 1km study area for the Proposed Development Site or Other DCO Land (which together constitute the DCO Site). Seven non-designated archaeological assets have been identified within the Proposed Development Site and Other DCO Land. All of the assets are catalogued in Appendix H (Part 1), Volume II of this PEI Report and shown on Figures 15-2 (Volume III of this PEI Report) for the Proposed Development Site and Figure 15-3a (Volume III of this PEI Report) and Figure 15-3b (Volume III of this PEI Report) for the associated infrastructure. The reference numbers are referred to in the text by their SGC/BCC HER reference number.
Designated Assets
15.3.36. All of the designated assets within 5km are illustrated on Figure 15-10 (Volume III of this PEI Report).
15.3.37. There are no designated assets within the Proposed Development Site or Other DCO Land or 1km study area.
15.3.38. There are five Scheduled Monuments with 5km and fourteen Grade I listed buildings and 14 Grade II* buildings within 5km. Most of these are concentrated at Blaise Hamlet and Kings Weston to the south of the Proposed Development Site or Other DCO Land.
15.3.39. There are 136 Grade II listed buildings, none of which are located within 2km of the Proposed Development Site. For this reason the latter have not been assessed within this PEI Report.
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Table 15-5: Scheduled Monuments, Registered Parks and Gardens and Grade I and II* Listed Buildings within 5km of the DCO Site
Ref No Description Period Designation Assessed Importance
1006999 Part of a minor Romano-British villa at Long Cross Roman Scheduled
Monument Very High
1021291 Heavy Anti-aircraft battery 520m east of Holes Mouth Modern Scheduled
Monument Very High
1020664 The Mere Bank and flanking ditches Iron Age Scheduled
Monument Very High
1004530
Blaise Castle. Three tower gothick style castle built (1795-9, listed grade II*)
Iron Age, Roman, Medieval, Post-Medieval
Scheduled Monument and Listed Building
(GII*)
Very High
1002479 King's Weston Hill camp, Henbury
Iron Age Scheduled Monument Very High
1001426
Blaise Castle and Hamlet Mid C18 landscape garden overlaid by late C18 landscape park,
Post-Medieval
Registered Park and Garden Very High
1000360
Royal Victoria Park Villa grounds of 12ha designed, along with the house, by Humphry Repton.
Post-Medieval
Registered Park and Garden Very High
1000335 Kings Weston House
Post-Medieval
Registered Park and Garden Very High
1202260 Blaise Hamlet, Double Cottage Post-Medieval
Grade I Listed Building Very High
1202261 Blaise Hamlet, Rose Cottage Post-Medieval
Grade I Listed Building Very High
1202262 Blaise Hamlet, Circular Cottage Post-Medieval
Grade I Listed Building Very High
1202263 Blaise Hamlet, Vine Cottage Post-Medieval
Grade I Listed Building Very High
1202264 Sundial to the middle of the green at Blaise Hamlet
Post-Medieval
Grade I Listed Building Very High
1202338 Loggia approximately 50m north of Kings Weston House
Post-Medieval
Grade I Listed Building Very High
1202339 The echo, approximately 300m South East of Kings Weston House
Post-Medieval
Grade I Listed Building Very High
1207747 Blaise Hamlet, Oak Cottage Post-Medieval
Grade I Listed Building Very High
1207760 Blaise hamlet, Dutch Cottage Post-Medieval
Grade I Listed Building Very High
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Ref No Description Period Designation Assessed Importance
1209729 Kings Weston House Post-
Medieval Grade I Listed
Building Very High
1209747 The Brewhouse, Kings Weston House
Post-Medieval
Grade I Listed Building Very High
1282246 Blaise Hamlet, Dial Cottage Post-Medieval
Grade I Listed Building Very High
1282247 Blaise Hamlet, Sweetbriar Cottage
Post-Medieval
Grade I Listed Building Very High
1282285 Blaise Hamlet, Diamond Cottage Post-Medieval
Grade I Listed Building Very High
1128857 Bishop's Farmhouse Post-Medieval
Grade II*Listed Building Very High
1187186 Two lodges and attached garden walls opposite former Kings Weston stables
Post-Medieval
Grade II*Listed Building Very High
1187199 Police station and attached walls to north east and south west, former Kings Weston stables
Post-Medieval
Grade II*Listed Building Very High
1202278 Castle lodge and gateway, Blaise Castle Estate
Post-Medieval
Grade II*Listed Building Very High
1202280 Timber lodge, Blaise Castle Estate
Post-Medieval
Grade II*Listed Building Very High
1205113 Church of St Mary the Virgin Post-Medieval
Grade II*Listed Building Very High
1205137 Memorial To Scipio Africanus 10m North West Of South Porch Of Church Of St Mary
Post-Medieval
Grade II*Listed Building Very High
1208115 Blaise Castle Post-Medieval
Grade II*Listed Building Very High
1279500 Blaise Castle House And Attached Wall
Post-Medieval
Grade II*Listed Building Very High
1282073 Gothic Arch Set In Garden Of Number 5, Longacre (Number 5 Not Included)
Post-Medieval
Grade II*Listed Building Very High
1293355 Model Dairy Approximately 60m East Of Blaise Castle House
Post-Medieval
Grade II*Listed Building Very High
1321095 Church Of All Saints Post-Medieval
Grade II*Listed Building Very High
1321097 Archway To Over Court Post-Medieval
Grade II*Listed Building Very High
1409175 Severn Tunnel East Portal (BSW1101)
Post-Medieval
Grade II*Listed Building Very High
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Non Designated Assets within 1km
15.3.40. In addition to the assets identified from the HER, a number of potential heritage assets have been identified from examination of the historic mapping for the Proposed Development Site. These assets are no longer extant and most have been destroyed by later construction, such as the underground gas and water pipelines beneath the Site. Only those assets which have the potential to be disturbed as part of the Proposed Development, for example if they are in areas which have seen little modern disturbance or are in areas of proposed new build, are discussed in this chapter.
Prehistoric (10,000BC - AD43)
15.3.41. One archaeological asset has been identified within the study area dating from the prehistoric period. Early Peat deposits (17668) containing burnt material (mainly plant material of Bronze Age date) were recorded at this site in bore holes, within a trial trench and during watching brief observations (Ref. 15-28). They were intermittent and no associated archaeological deposits were recorded.
15.3.42. Just beyond the south and north boundaries of the Generating Station Site are the locations of two possible earthwork enclosures (2994/5), delineated with ditches and surrounded by ridge and furrow, indicating the possibly site of a past farmstead. The two enclosures are contiguous and sub-rectangular in form.
15.3.43. To the south of the Generating Station Site, a square enclosure lying within an area of ridge and furrow is recorded in the South Gloucestershire HER (SGHER) as Neolithic in Date (5224). The remains comprise three sides of a rectangular enclosure defined by earthworks. Another square shaped enclosure (5226) also recorded as Neolithic in date is located in small field to the northwest of Crook’s Marsh Farm. A further Neolithic or late prehistoric enclosure (5229) is located in field just north of Shipman's Gout to the north of Vimpennys Common. A prehistoric enclosure (5230) surrounded by ridge and furrow abuts the secondary rhine on the south side of Minors Lane.
15.3.44. A buried land surface of early prehistoric date is located at Elmington Farm, Almonsbury (6449). It consisted of a peat deposit containing well-preserved Phragmites was observed in a trial pit in 1990 (Ref. 15-18).
15.3.45. A prehistoric enclosure (6677) is located at Hallen Marsh, Bristol.
15.3.46. An area of peat deposit (7081) probably part of the submerged forest deposit at Severn Beach is marked on the 1:100,000 OS Maps to the southwest of Severn Beach.
15.3.47. A palaeo-environmental borehole sample was taken from a location within the Generating Station Site and is recorded on the SGHER (14325, 14326). A
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detailed report on the results is presented in the Pucklechurch to Seabank Pipe Line Archaeological report (Ref. 15-11).
15.3.48. Mesolithic Activity has been recorded in a buried land surface at Willow Farm Minors Lane Hallen, Bristol(20104). The Holocene stratigraphy at Willow Farm overlies a 0.28m thick layer of soliflucted flint/chalk gravel and silt at 16.36m (-9.90m AOD), below ground level (bgl) which in turn overlies the Mercia Mudstone Group bedrock (see Figure 15-6 (Volume III of this PEI Report)). A soil pre-dating 7310-7030 Calibrated BC is the first Holocene stratum, but this terrestrial unit it overlain by lagoonal strata, then a freshwater fen peat dating from 7310-7030 to 6440-6250 Calibrated. BC. Magnetic susceptibility evidence from the peat suggest that the fen surface was been burnt as it accreted, while considerable quantities of microscopic charcoal were noted at the same depths during the palynological study. The burning of the vegetation may indicate direct human activity either to prepare for agricultural activity or to aid hunting.
Roman (AD43 – 410)
15.3.49. Located within the western part of the Generating Station Site, a series of ditches (14323) containing Roman material was noted initially during a watching brief which was followed by excavation (Ref. 15-19).
15.3.50. A few hundred metres to the south is evidence of Romano British occupation revealed by extraction of alluvial clay by the Severn Valley Brick Company (4896). A series of ditches, some probably associated with small rectangular enclosures sealed by 0.5m of post Roman deposits as they appear in the sides and across the 80m wide working face of the clay pit.
15.3.51. An enclosure is located at Minors Farm in Minors Lane, Pilning (6162) and is identified in the SGHER as being of Roman date.
15.3.52. Roman occupation to the south of Minors Farm was indicated by a ditch (15816) recorded in 1982 at Monks Lane, Crook’s Marsh, Pilning (Ref. 15-19). It is probably part of the wider Roman Settlement (SGHER 4896, (Ref. 15-20) recorded in the area. This wider settlement evidence is represented by a shallow feature (15817) possibly of Roman date and a series of ditches (15818) recorded in the edge of a clay pit in 1982. The same settlement is also recorded in the Bristol City HER (BCHER) (3,002m).
15.3.53. A Roman ditch and pit (20199) were revealed during archaeological work in 2012 at the site of the Severnside Energy Recovery Centre, to the west of the Generating Station Site. Roman remains were present in one trench and could be seen survive from within 0.5m of the present ground level. Parallel to, and approximately 4m away from the Roman ditch was a post hole.
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Early Medieval and Medieval (AD410 – 1066)
15.3.54. A manor house of possible early medieval date is indicated from a field named ‘Hasborough’ (12778) on the Tithe map of Henbury (1840), approximately 1km southeast of the Proposed Development Site. The name is of Saxon origin meaning fortified place (probably manor house) of the hazels. It is possible that this field contained a Saxon Manor house although may have belonged to it. Although the field has been partly destroyed by the Motorway (M5) and trial trenched with no results it is possible that the undisturbed part of the field contains the manor (Ref. 15-21).
Medieval & Post-medieval (AD1066 – 1750)
15.3.55. A pit (14321), perhaps originally containing the remains of a sheep and a small quantity of medieval ceramics was recorded at this location within the CCR Site during a watching brief on the installation of the Abson gas pipeline.
15.3.56. A small area of remnant ridge and furrow (17951) is recorded to the east of the Generating Station Site close to the Severn Road.
15.3.57. A possible Farmstead of medieval date (2992) is located approximately 450m north of the Proposed Development Site. The area is bounded by ditches and surrounded by ridge and furrow, possibly indicating the former site of farm building remains, enclosures and a trackway leading northwest, indicating the site of a deserted farm.
15.3.58. A possible enclosure (2994) of medieval date is located just outside of the southern boundary of the Generating Station Site and is visible on aerial photographs. There is a possible enclosure with underlying ridge and furrow. A watching brief carried out on a cable trench on the southern boundary of the Proposed Development Site along Ableton Lane exposed a ditch containing Roman pottery not far from this Site, which may suggest a Roman date for the enclosure.
15.3.59. A farmhouse and farm building which is marked on aerial photographs approximately 600m south of the Proposed Development Site, but is no longer marked on OS maps, is probably medieval in date (5225).
15.3.60. A possible moated site (5320) is located at Vimpennys Farm, Pilning. The farmstead possibly relates to early freehold held by the manor of Compton Greenfield. The farm was demolished to make way for new development in the 1950s.
15.3.61. A fishpond (5797) was once located close to Minors Lane. There are 13th Century references to a fishpond in this area which changed hands between two manors. In the Ashton Court Papers there is a "Fishpond" field name on the tithe award.
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15.3.62. A possible site of a mill (5798) exists in the vicinity at an undefined location. There is mention of a change of ownership of a mill in the 13th Century in the Ashton Court Papers (Denison and Iles 1985). The "old mill of Peter Croc" is said to lie "on the west side of the way which leads to the seawall" (shown on the Almondsbury Tythe Map 1838). In 1577, there is reference to "all tithes of lands and tenants of Cooky's Marsh and 2 sheaves of one croft called the mill" (Denison and Iles 1985). On the Henbury Tithe Award (1839) the field is called "Millmoat".
15.3.63. The remains of a building and small derelict enclosure visible on an aerial photograph suggest the possible site of a farm approximately 300m north of the Generating Station Site (6716) (Ref. 15-22).
15.3.64. Approximately 600m northwest of the Generating Station Site is an irregular, curving, double banked feature (6717) approximately 15-20m wide and 120m long with regular cross banking, which may be medieval but also possibly fairly recent in origin.
15.3.65. Crook’s Marsh Farm (9250) was recorded on the 1st edition OS map, alongside a second farm, forming a group of buildings, possibly of medieval origin. The name was recorded at least as early as 1496 (Ref. 15-23). The farm is also recorded in the BCHER (2046m).
15.3.66. A settlement at Minors farmstead (9251) was depicted on the 1st edition OS map (1880-1882), but its earlier history is obscure. The lane was recorded from at the latest 1690. The structures and deposits at this site may begin in the medieval period, but this is not confirmed at present.
15.3.67. A farm was depicted at Hook Farm, Vimpennys Common, Pilning (9254) on the 1st edition OS map. Only one building of the complex appears to have survived in 1975 (OS Map), but it had disappeared by 1991. An archaeological survey was carried out on the site in 1996. A medieval origin was suggested by the moat around part of the site. Some of the buildings could date as early as the 16th Century (Wessex Archaeology 1996). The physical layout of this site has been established by 1835 with much building work going on between the date of the tithe map and the 1st edition OS map.
15.3.68. Minors Lane (11112) is located immediately south of the Proposed Development Site. This lane and the adjacent secondary rhine was recognised by the archaeological team as a potentially early landscape feature.
15.3.69. The moat at Hook Farm Vimpennys Common, Pilning (12776) is probably medieval in origin.
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15.3.70. Lower Gallows Acre (12780) to the east of the M49 is marked on the Henbury Tithe and the name could indicate the site of a gallows, or that it belonged to a hangman.
15.3.71. The 3rd edition OS map depicts two farms on either side of the end of a road from the interior of the marsh to the coast (12995). The southwestern building and the road were visible as a cropmark in 1991. Both farms were in existence by the date of the 1st edition OS map, when a third building to the east of the southwestern building (probably a third farm lying in a small close) was recorded. The other buildings lie within the area of BCHER (9225).
15.3.72. An irregular enclosure or settlement site (13509) surrounded by rhines may indicate the site of early re-colonisation of the Severn Levels during the medieval period (Ref. 15-21).
15.3.73. Also on the water pipeline route, a farm of post-medieval date (14322) noted on the 1st edition OS map was avoided by the construction of the previous pipelines.
15.3.74. The extent of post medieval settlement at Severn Farm, Vimpenny Common, Pilning (16369) is shown on the 1st edition OS map. The SGHER suggests there was a medieval farmstead on this site. The approximate extent of post medieval settlement at Hook Farm Pilning (16378) is shown on the 1st edition OS map. This site also has medieval origins. The post medieval settlement at Stowick Farn North Pilning is also shown on the 1st edition OS map.
15.3.75. Ridge and Furrow (18998/9) is visible on aerial photographs, as shown in Figure 3-4a (Volume III of this PEI Report).
15.3.76. A possible Post Medieval groyne (19960) is visible as a structure on aerial photographs (1465110). The structure is located on Chittening Warth at New Pill Gout. The structure is defined by a double row of wooden stakes that extend at right angles to the shore and has a total length of 150m and orientated northwest/southeast. The present course of the New Pill follows the line of wooden stakes which may have been constructed to channel the Pill and therefore prevent erosion of the peat layers on the accreting on the foreshore. The structure was visible on aerial photographs taken after 1990 (Ref. 15-24).
15.3.77. A Medieval and/or Post Medieval fish weir is visible on gravel banks (19962) as a wooden structure on aerial photographs (Ref. 15-24). The weir is located on the Gravel Banks south of Severn Beach. The weir is defined by a curving double row of wooden stakes which measures a total length of 230m and orientated northwest/southeast. The weir would form a rank or `hedge’ for the placement of putts or putchers (basket traps). The fish weir was still visible on aerial photographs taken in 1969 as a linear feature in the mud but no wooden posts are visible.
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15.3.78. Worthy Farm (2164M) is recorded in the Feet of Fines for 1241 when the property is named "La Wrthie", approximately 500m south of the Proposed Development Site. The property was recorded by the tithe survey in 1841. It is shown by the 1915 Ordnance Survey map (Gloucestershire sheet LXVII.10) as a farmhouse and complex of farm buildings.
15.3.79. The site of a building (2166M) of possible post-medieval date is shown on the 1915 OS plan of this area (Glos Sheet LXVII.10). The map depicts a building in a narrow enclosure alongside the road. It now lies under an industrial complex. Structures and deposits relating to this building may survive.
15.3.80. A dwelling or farmstead is located on the bank of the River Severn at Chittening Warth (2167M). Human activity began on this site in the eleventh century when the surrounding area was still saltmarsh and occupation continued into the twentieth century.
15.3.81. A building (possibly two adjoining dwellings) (2168M) was depicted at this location in 1830 (Ordnance Survey 1:63360) and 1915 Archaeological deposits relating to these buildings almost certainly survive.
15.3.82. Washingpool Farm (2172M) was a farm was depicted on the 1830 Ordnance Survey map. The range of buildings was recorded in 1915.
15.3.83. The bridge over Stup Pill Rhine at Washingpool Lane (2256M) carries Washingpool Lane across Stup Pill Rhine at Red Spoltt Gout. It is built of stone and has later brick reinforcing of the arches. The parapet is modern.
15.3.84. A cottage and garden (2258M) are recorded at Red Splot (Reed Splatt) Gout. The building was located to the south of Washingpool Lane and was extant by c.1810, being shown on a survey of that date. The building is recorded by the 1841 tithe assessment.
15.3.85. A house on the western side of Severn Road, Chittening (2259M) is recorded by the 1841 tithe survey and is shown on the Ordnance Survey maps of 1881 and 1915.
15.3.86. A sub-rectangular ditched enclosure (2277M) is located to the south of Severn Road, Chittening.
15.3.87. Chittening Farm (2493M) is shown on the tithe survey of 1841, noting that it was owned by Sir John Smyth and occupied by a tenant. Taylor's 1773 map of the area shows the site of Chittening Farm as open fields
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Early Modern & Modern (1750 – present)
15.3.88. A sheep wash located just west of the M48 motorway (6450) lies on top of a structure which appears to be earlier, and mid-19th century pottery and glass was found in cattle disturbances around this site.
15.3.89. A fish trap is located on the foreshore at New Pill Gout Pilning. The remains comprise several short linear groups of stakes in five parallel lines. The fish trap is 2m wide and extends for 30m running along the beach.
15.3.90. A settlement is recorded on the 1st edition OS map in the area of Stowick Farm just outside of the northeast corner of the Generating Station Site (9224). This site was referred to as early as 1287, the name originally being `Stonwyk', perhaps implying the existence of stone buildings at the site at this early date. This site may be more than usually important, as the placename implies involving both the `stone' element, and the early farm name `wic'. Both may imply the existence of very early occupation at this site, similar to that at Redwick and Northwick.
15.3.91. There is a former medieval settlement located at Vimpennys Common (9255) to the north of the Generating Station Site. Before its enclosure, the Common comprised a few hectares of open land, with at least six occupation sites around it. It is medieval in origin, and has since been enclosed and partly built over.
15.3.92. The Imperial Chemical Industry works at Severnside (13954) was established shortly after World War Two (WWII).
15.3.93. To the east of the Generating Station Site is a railway branch (16342) linking the Former Terra Nitrogen and ICI site to the Avonmouth Seven Tunnel Railway. The works dates to shortly after WWII and the railway is presumably of similar date.
15.3.94. A 20th Century wreck (19663) is located 580m north of Stuppill Gout in the Severn Estuary. The wreck is partially submerged in the intertidal muds and measures 19m long north/south and 5m wide east/west. The wreck is still visible on aerial photographs taken in 1969 and was found to be extant during field survey in 1995.
15.3.95. A possible 20th century groyne (19978) is visible as a structure on aerial photographs. The structure is located on Chittening Warth north of Stuppill Gout and centred at location ST 5302 8230. The structure is a row of wooden stakes that extends at a right angle to the shore and has a total length of 180m and orientated northwest/southeast. The structure was visible on aerial photographs taken after 1980.
15.3.96. A barrage balloon anchor point (19088) was recorded on aerial photographs. It may have been removed before the end of WWII.
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15.3.97. The site of a former Military Camp (19089) of modern date was formerly located at the SITA Severnside Energy Recovery Centre, Severn Road. The camp consisted of a small group of ancillary buildings and huts associated with barrage balloon anchor (SGHER 19088) and is noted in Cotswold Archaeology Desk Based Assessment (Ref. 15-24).
15.3.98. A small circular platform, less than 20m in diameter, with a bank around outer lip is recorded in the BCHER (2,098m). The feature is possibly modern and could be a bomb crater of WWII.
15.3.99. Bank Farm (2,163m) lies on the north side of Severn Road; the site of the farm is shown by Taylor's map of the area in 1773 (not illustrated) as an open field. Bank Farm had been built in the western part of the field by the time of the 1841 Henbury tithe map.
15.3.100. The site of a house is recorded at Hallen Marsh (2,184m). The house is recorded by Benjamin Donne's 1769 Map of the 11 miles around Bristol.
15.3.101. An Army Ordnance Department store (3,097m) is located approximately 110m to the north of Washingpool Farm. The store was built in 1918 to serve National Filling Factory No.23 and is recorded by a plan in the National Archives (MUN 4/1753). Another Armament Store (3,231m) depicted on 1920s Air photograph (Ref 24)). The store was linked to the complex of structures associated with the National Filling Factory at Chittening (2750M). A third store (3,231m) lay to the north and east of Washingpool Farm.
Historic Buildings
15.3.102. This subsection provides a summary of information available on the National Heritage List, SGCC and BCC HER’s.
15.3.103. There are no listed buildings within the Proposed Development Site, Other DCO Land, or within 1km of the Generating Station Site.
15.3.104. Between 2km and 5km from the DCO Site, a total of 14 Grade I and 14 II* listed buildings have been identified. There are also 164 Grade II Listed buildings within 5km.
15.3.105. None of the listed buildings are within 2km of the Proposed Development Site. The Grade I and II* buildings are all located to the south of the Proposed Development Site, at either Blaise Castle Hamlet or Kings Weston House (Figure 15-10 (Volume III of this PEI Report)).
15.3.106. Blaise Castle (Grade II* 1208115) and a timber Lodge (Grade II* 1202280) are located approximately 4.5km to the south of the Proposed Development Site. Slightly closer to the Site at Blaise Hamlet there are several Grade I cottages and
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a sundial. All of these are post-medieval in date are located approximately 4km south of the Proposed Development Site (1202260-64, 1207747, 1207760, 1282246/7, 1282285). Grade II* listed buildings at Blasé Hamlet include a Castle Lodge (1202278) and Gateway (1202280), A House (1279500) and Model Diary (1293555).
15.3.107. To the west of Blaise Hamlet at Kings Weston, approximately 4.7km to the south west of the Proposed Development Site, are four Grade I buildings: Kings Weston House (1209729), a Brew house (1209747), a Loggia (1202338) and ‘The Echo’ (1202339). In addition there are two Grade II* buildings, comprising two lodges (1187186) and a Police Station (1187199). Further afield to the east is the Grade II* East Portal of the Severn Tunnel (1409075).
15.3.108. Outside of Blaise Castle Hamlet or Kings Weston House there a further two Grade II* listed buildings. The Church of St Mary The Virgin (1205113) is located to the south of Blaise Hamlet and a gothic arch is located further to the east (1282073).
Historic Maps
Proposed Development Site
15.3.109. The 1799 plan of land in the Hamlet of Crook’s Marsh (1799) Bristol Records Office (BRO) 31965/34 (Map A in Appendix H (Part 3), Volume II of this PEI Report) depicts the site as agricultural fields, subdivided by hedgerows and drainage channels (Rhynes). Minors Lane is apparent and two further trackways extend from the lane across the Generating Station Site towards Crook’s Marsh. A small square enclosure containing a single small rectangular building is located immediately to the north of where Minors Lane enters the Proposed Development Site from the south.
15.3.110. The 1825 Plan of Estates belonging to Edward Simpson (BRO (Sturge) 3165/33) (Map B in Appendix H (Part 3), Volume II of this PEI Report) depicts the building in the southern corner of the Proposed Development Site with a further square building a short distance to the north on the west side of Minors Lane. Perhaps most interestingly though is the written annotation referring to large field in the southeast corner of the Proposed Development Site (immediately to the west of the enclosure containing the small building). This field is referred to as an ‘Old House Ground’. This is particularly important as this field is also the location of the low mound identified by the geophysical survey (see Figure 15-7a (Volume III of this PEI Report)), which may represent a house platform of medieval or late medieval date (Ref. 15-26). Further evidence for this has come from pottery retrieved during a geotechnical monitoring exercise.
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15.3.111. The 1st Edition OS map (Map C in Appendix H (Part 3), Volume II of this PEI Report) presents the two enclosures located along the north side of Minors Lane at least two buildings are present in the eastern of the two enclosures. Both enclosures contain a number of trees on this map. The 1903 OS map or any of the subsequent O.S maps (Maps E-I in Appendix H3, Volume II of this PEI Report) do not show any significant changes to the site.
Other DCO Land
15.3.112. The majority of the pipeline route has been assessed previously through several Desk Assessments (see Appendix H (Part 1), Volume II of this PEI Report). As a result, the assessment has been restricted to inclusion of historic maps from the 1st edition OS maps.
15.3.113. The entire route is depicted on the 1886 OS map (Map 3 in Appendix H (Part 3), Volume II of this PEI Report). This shows the agricultural nature of the landscape at this time. The cooling water pipeline is depicted passing through fields, orchards and close to a number of farms, most notably, Worthy, Chittening and Washingpool Farms towards the northern end of the route and Green Splott Farm further south. During WWI, several buildings in relatively close proximity to the route were in military use including a hospital and various store buildings. These are listed in the baseline text and illustrated on Figure 15-3a and Figure 5-3b (Volume III of this PEI Report). The area along the route remained predominantly agricultural until the 1950’s when the first major industrial buildings appeared. The area became progressively more industrialised up to the present day.
15.4. Development Design and Impact Avoidance
15.4.1. There are no specific avoidance measures that have been implemented in the design of the Proposed Development relevant to archaeology and cultural heritage.
15.4.2. The proposed cooling water pipeline corridor was selected partially based on preliminary archaeological investigations. Given the sensitivity of the area and especially the coastline along the Severn Estuary, it was decided prudent to follow the route of the existing pipelines between Bristol WWTW and Seabank 1 & 2 as far as possible.
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15.5. Potential Effects and Mitigation Measures
Construction Phase
15.5.1. For ease of reference, the assessment of construction impacts has been split into the main development parcels for the Proposed Development Site and associated infrastructure.
15.5.2. The areas of potential archaeological impact include the peaking plant buildings, turbine buildings, HRSG buildings, generator transformers, water storage tanks, and pump pits for the cooling towers. The location of these structures are shown on Figure 4-1a., (Volume III of this PEI Report).
15.5.3. Only those development parcels where an impact might be experienced are discussed below.
Proposed Development Site
15.5.4. Although the Proposed Development is expected to be constructed upon imported material up to an average 2.2m in depth, construction works for the turbine and HRSG buildings, and cooling water pump pits may include the development of foundations which require limited below-ground excavation resulting in below ground disturbance to potential archaeological remains should they be present. The structures requiring foundations potentially below the existing ground levels is illustrated in Figure 15-11 (for the single-shaft configuration) and Figure 15-12 (for the multi-shaft configuration), in Volume III of this PEI Report.
15.5.5. Any archaeological remains present are likely to date to the Iron Age or Romano British periods but there is also evidence for occupation during the later medieval period with a possible house platform being present in the southern part of the Generating Station Site. The current design suggests that Roman ditch features may be impacted by piling and foundations. The historic significance of any archaeological remains revealed during such ground works is not currently known but is likely to be Medium. Due to the largely raised nature of the development there will be only discrete areas of below ground impact (e.g. pile caps and cooling foundations). Construction works for the main structures are not expected to physically affect the possible house platform feature identified in the geophysical survey, due to its location (see Figure 15-7a, Volume III of this PEI Report). However, it is possible that an underground pipeline will be trenched through this location (the construction technique has not been confirmed and may comprise boring or HDD, or even above ground pipe). If this is confirmed, impact upon buried archaeological remains is likely to occur.
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15.5.6. Given the importance of these features, the potential effect is considered major adverse without appropriate mitigation. Archaeological remains such as ditches or pits can be dealt with through an archaeological watching brief on initial removal of topsoil material however. Although not envisaged, should there be a potential for effects on the potential house platform feature, further information may be required through an evaluation exercise in order to prepare an appropriate mitigation strategy and to assess the potential for impact.
15.5.7. Providing that the ground conditions are still intact following work onsite by third parties developing the Severnside Energy Recovery Centre, new Red Rhine channel, and Spine Access Road (see Chapter 7: Assessment Methodology), an archaeological evaluation exercise will be undertaken prior to issue of the final ES within the locations of potential below ground impact. This may include impacts on the small number of potential ditch locations discussed above as identified by the geophysical survey. Should the evaluation confirm the presence of significant archaeological remains, particularly relating to domestic occupation, an open area excavation may be required to mitigate the effect of the Proposed Development.
CCR Site (Temporary Compound)
15.5.8. The CCR Site will be used for the Contractor Compound, parking during construction, and laydown of materials, as discussed in Chapter 5: Enabling Works and Construction. These activities will initially include topsoil strip, which is expected to penetrate 200mm to 300mm below the existing ground levels and should therefore cause minimal impact to any below ground archaeology. The effect on the CCR Site is therefore considered to be negligible and is not discussed further.
15.5.9. Both evaluation and mitigation works will be detailed in separate Written Schemes of Investigation (WSI) to be agreed by SGC, BCC and English Heritage.
15.5.10. Following mitigation the residual effect is considered minor adverse.
Other DCO Land
15.5.11. Construction works associated with the proposed cooling water pipeline have the potential to impact archaeological remains. However, disturbance of any potential archaeological remains may be somewhat limited as the pipe trench will be located within the nominally 30m wide corridor that constitutes the Other DCO Land and in close proximity to the existing pipelines. It is likely that some of the trench will be excavated through made ground of modern date. However, at some points the trench may be excavated through previously undisturbed ground. Figure 15-13a to Figure 15-13e (Volume III of this PEI Report) illustrate
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the area of the proposed cooling water pipeline corridor that has been previously disturbed.
15.5.12. The trench will be approximately 2m depth and is likely to expose organic deposits relating to the prehistoric occupation of the area that may be of significant archaeological value. Although the trench will be generally 3m wide there will also be a construction corridor nominally 20m wide to allow areas for soil stockpiles, laydown, vehicle access etc. The corridor for the previous pipeline will no doubt have caused significant disturbance. However, where sections of the corridor in undeveloped areas will be stripped of topsoil prior to the trenching works there is the potential for these ground works to disturb archaeological remains.
15.5.13. Based on the baseline information, the importance of the pipeline corridor is considered to be Low. The magnitude of change should a feature be disturbed or destroyed is also considered Low, which would result in a minor adverse effect prior to mitigation.
An archaeological watching brief, in accordance with a Written Scheme of Investigation to be approved by BCC, will be undertaken during initial topsoil strip of sections along the cooling water pipeline in areas not currently occupied by hardstanding. The resulting residual effect is therefore considered to be of negligible significance.
Operational Phase
15.5.14. It is not considered likely that any activities pertaining to the operation or maintenance of the Proposed Development or cooling water pipeline will effect below ground archaeological remains.
15.5.15. The physical appearance of the Proposed Development will affect the setting of two assets listed below. The CCGT stacks will be erected to 90m height above the finished ground level (up to 98.5m AOD) and the peaking plant stacks to 45m above the finished ground level (up to 53.5m AOD). The main buildings onsite are the HRSG buildings which will be up to 45m high (up to 53.5m AOD). The maximum heights and massing of the buildings and structures are presented in more detail in Chapter 4: Project Description.
Proposed Development Site
Assets of Very High or High Value
15.5.16. Blaise Castle and Kings Weston House have been assessed as being of Very High importance.
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15.5.17. The construction of the Proposed Development and associated infrastructure will not directly impact any designated or non-designated built heritage assets within the 5km study area.
15.5.18. There will be a minor adverse visual impacts from the HRSG and turbine buildings and stacks on views from the northeast, from the upper storeys of the Grade II* designated building of Blaise Castle. This is situated on a ridge to the east of the Proposed Development at approximately 88m AOD. There will be clear views of the Proposed Development from the upper floors of the castle which is a late eighteenth century folly. Views from ground level will be restricted by high woodland surrounding the castle. The historic setting of ten Grade I buildings at Blaise Hamlet and four Grade II* structures located further to the southeast will not be affected due to a much lower elevation and screening by vegetation and modern development.
15.5.19. There is therefore considered to be a ‘Minimal’ magnitude of change on Blaise Castle, meaning that there is a change to the asset that hardly affects significance and no real change in the ability to understand and appreciate the resource and its historical context and setting.
15.5.20. Taking into account both the magnitude of change and importance, the residual effect (based on the criteria in Table 15-4) on Blaise Castle is judged to be minor adverse.
15.5.21. Kings Weston House is well screened year round by surrounding vegetation and is therefore be protected from views of the Proposed Development, leading to ‘No Change’ and an effect of negligible significance.
15.5.22. No further assets of very high or high value are anticipated to experience any change as a result of the Proposed Development: The residual effect on all other designated assets is therefore expected to be negligible.
Assets of Medium Value
15.5.23. The following assets are considered to be of Medium value:
• Enclosure Seabank Pucklechurch Pipeline, Almondsbury (14322), within the southern part of the Proposed Development Site; and
• Possible House Platform within site (not currently on HER), illustrated on Figure 15-7a (Volume III of this PEI Report).
15.5.24. These features are situated within the Utilities, Services and Landscaping Area, which is reserved for the realignment of underground utilities and, in this particular location, ruderal vegetation or grassland (see Chapter 4: Project Description). An archaeological evaluation may be required in advance of construction should this part of the pipeline be installed using an open trench,
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which could affect the potential house platform. In addition, a watching brief will be undertaken during construction in these areas, which, because of the localised impact on these widespread features, is anticipated to result in a ‘Minimal’ change of magnitude at these locations. Based on the criteria in Table 15-4, is anticipated to lead to a residual effect of minor adverse significance.
Assets of Low Value
15.5.25. The Ridge and Furrow Cultivation (2) New Pill Gout Chitterling Gout Pilning (18999) asset located within the Generating Station Site is considered of ‘Low’ value, but is expected to experience a ‘High’ magnitude of change due to the Proposed Development. This corresponds with change such that the significance of the asset is totally altered or destroyed, or comprehensive change to setting affecting significance, resulting in changes in our ability to understand and appreciate the resource and its historical context and setting. Based on the criteria presented in Table 15-4, the significance of this effect is considered to be moderate adverse without appropriate mitigation, which is discussed below.
15.5.26. The Series of ditches (14323) within the western part of the Proposed Development Site and Early Peat deposits (17668) approximately 500m northwest of the Site, are considered of ‘Low’ value and, due to the localised impact on this widespread feature, it is considered that it will experience a ‘Minimal’ magnitude of change. According to Table 15-4, the residual effect is considered to be negligible on these assets.
15.5.27. Providing that the ground conditions are still intact following work onsite by the third parties, an archaeological evaluation exercise will be undertaken prior to issue of the final ES within the locations of potential below ground impact. This will add knowledge but will not reduce the permanent removal of the asset and therefore the residual effect is considered minor adverse.
15.5.28. Taking into account the proposed mitigation, the residual effect on the Iron Age/ Roman enclosure and Medieval/Post medieval enclosure within the Proposed Development Site is deemed to be minor adverse. The residual effect on the Roman Field system is also judged to be minor adverse.
Associated Infrastructure
15.5.29. There are no assets of Very High, High or Moderate value expected within the construction corridor of the cooling water pipeline or electrical connection. This is known because the route of the pipeline has been previously assessed through desk based assessment (see section 15.1 and Appendix H (Part 1), Volume II of this PEI, Event no’s 20079 and Event no 20080). The watching brief (Event no 20080) did not reveal any archaeological remains although in several areas
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encountered buried land deposits. There are no other archaeological remains expected to be impacted by the cooling water pipeline.
Assets of Low Value
15.5.30. The Buried Land Surface- Neolithic deposit at Smoke Lane (3237M) is considered of ‘Low’ value and is expected to experience a ‘Minimal’ magnitude of change through the installation of the cooling water pipeline, given it is approximately 50m west of the construction corridor. According to Table 15-4, the residual effect is anticipated to be negligible.
15.5.31. Mitigation has been proposed in the form of a programme of archaeological fieldwork during initial topsoil strip of sections along the cooling water pipeline in areas not currently occupied by hardstanding. This will add knowledge but will not reduce the permanent removal of the asset and therefore the residual effect is minor adverse.
Decommissioning Phase
15.5.32. It is not expected that the decommissioning phase would have the potential to disturb any below ground archaeological features. The work should not require new, undisturbed areas to be affected, and hence would be expected to lead to ‘No Change’ and an effect of negligible significance.
15.5.33. The removal of the Proposed Development is expected to reverse the minor adverse effect on the setting of Blaise Castle, hence leading to a minor beneficial effect. Any negative effects on setting would arise from cranes or other large mobile plant onsite, which would be temporary and unlikely to create a significant effect on these heritage assets.
15.6. Residual Effects
Archaeological Effects
Proposed Development Site 15.6.1. The Generating Station Site will be raised by up to an average 2.2m above the
current ground level to a maximum 8.5m AOD. Following the assessment of potential effects, mitigation has been proposed to reduce the localised impacts from foundation construction upon the identified heritage assets.
15.6.2. The assessment has identified the potential for archaeological remains dating from the Prehistoric, Roman and medieval periods to be present within the Proposed Development Site. However, the raising of the ground level within the Generating Station Site suggests that there should be no impact upon these remains.
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15.6.3. The areas of potential archaeological impact include the peaking plant buildings, turbine buildings, HRSG buildings, generator transformers, water storage tanks, and pump pits for the cooling towers, the locations of which are shown on Figure 4-1a,(Volume III of this PEI Report). Based on the depth of archaeological features in this part of the Site, excavations greater than 2.0m below current ground level in these locations could disturb deposits that may retain archaeological remains of Iron Age or Roman date. Horizons of organic deposits containing material of palaeoenvironmental interest may also be located at greater depths. As mentioned above, providing that the ground conditions are still intact following work onsite by the third parties, an archaeological evaluation exercise will be undertaken of these areas prior to issue of the final ES.
15.6.4. There are two scheduled monuments situated on elevated ground within the 5km study area to the east that will be afforded partial views of the Proposed Development. The first is the Scheduled Monument of Blaise Castle approximately 3.5km southeast of the Proposed Development Site at approximately 88m AOD. There is predicted to be a minor adverse effect on the historic setting of this SAM which is defined by a parkland setting.
15.6.5. The historic setting of the Iron Age hill fort at Kings Weston Camp at Henbury will not be compromised due to dense woodland which screens all views to and from the Proposed Development Site, resulting in a negligible effect.
15.6.6. The historic setting of the remaining Scheduled monument of the Anti-Aircraft Battery to the 2.1km to the west and the Mere Bank 3.3km to the west of the Proposed Development Site will not be impacted due to the level nature of the terrain and intervening development. This is also the case for the final SAM within the 5km study area, which are the remains of a minor Romano-British villa at Long Cross 4.8km to the southwest.
Other DCO Land 15.6.7. The proposed cooling water pipeline is intended to run adjacent to the west of the
route of the current cooling water pipelines to and from Seabank 1 & 2. The BCC HER records numerous investigations and a small number of known assets within 1km of the cooling water pipeline. The locations of the archaeological events and monuments is shown on Figure 15-2, Figure 15-3a, and Figure 15-3b (Volume III of this PEI) and detailed in Appendix H (Part 4), Volume II of this PEI.
15.6.8. The construction trench and corridor for the previous pipeline was archaeologically monitored and the proposed pipeline will therefore be located in ground that has been previously disturbed. There is low potential for archaeological remains to exist in residual areas of the proposed nominally 30m wide pipeline corridor for the cooling water pipeline. As mentioned above, topsoil stripping in these areas will be monitored archaeologically at the time of works
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being undertaken. A geoarchaeological specialist will also be commissioned to inspect any profiles revealed that may contain the potential soil horizon of Neolithic date. The geoarchaeologist will take samples where suitable deposits are revealed. The sampling strategy will be agreed with the Regional Science Advisor for English Heritage.
15.6.9. The scheduled monument of Mere Bank (1020664, Figure 15-3 (Volume III of this PEI)) is located approximately 65m to the south of the southern terminus of the proposed cooling water pipeline corridor but will not be directly affected by the construction of the cooling water pipeline.
Built Heritage Effects
15.6.10. The construction of the Proposed Development and associated infrastructure will not directly impact any designated or non-designated built heritage assets within the 5km study area. There will be a minor adverse visual impacts from the cooling towers and stacks on views from the northeast, from the upper storeys of the Grade II* designated building of Blaise Castle. Views from ground level will be restricted by high woodland surrounding the castle. The historic setting of ten Grade I buildings at Blaise Hamlet and four Grade II* structures located further to the southeast will not be affected due to a much lower elevation and screening by vegetation and modern development.
15.6.11. There will be occasional distant views of the Proposed Development from the Registered Park and Garden of Kings Weston House 5km to the southwest. The CCGT stacks will be set against a background of the Severn Estuary which will decrease the potential visual impact. It is therefore considered that the historic setting of Kings Weston Park and the Grade I listed building of Kings Weston House will not be affected. The residual effect on the significance of the setting of Kings Weston Park is therefore considered to be negligible.
15.6.12. Table 15-6 provides a summary of the conclusions of this PEI chapter.
Table 15-6: Summary of Cultural Heritage Residual Effects Asset Name Importance Potential
Impact Nature of Impact
Mitigation Measures Residual Effect
Proposed Development Site Iron Age/Medieval Enclosure 2994 (5)
Medium Physical impact from construction phase
Permanent Trial trenching followed by Excavation and post-excavation analysis
Minor Adverse
Post medieval Enclosure 14322
Medium Physical impact from landscaping proposals
Permanent Watching brief on Landscaping works in this area
Minor Adverse
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Asset Name Importance Potential Impact
Nature of Impact
Mitigation Measures Residual Effect
Roman Field System 14323
Medium Physical impact from construction phase
Permanent Trial trenching followed by Excavation and post-excavation analysis
Minor Adverse
Ridge and Furrow Cultivation 18999
Medium Physical impact from construction phase
Permanent Trial trenching followed by Excavation and post-excavation analysis
Minor Adverse
Mound (House Platform?)
Potentially Medium
Possible physical impact from construction phase
Permanent Trial trenching followed by Excavation and post-excavation analysis
Minor Adverse
Blaise Castle Very High Impact on significance of setting
Permanent None Minor Adverse
Kings Weston House
Very High Impact on significance of setting
Permanent None Negligible
Associated Infrastructure Buried Soil Horizon(s) Identified in previous watching brief
Medium Physical impact from construction
Permanent Archaeological Watching Brief in selected areas (Figure 15- 13a-e, Volume III)
Minor Adverse
Heritage Features such as laise Castle and Kings Weston House
Very High Impact on significance of setting
Permanent None Negligible
15.7. Cumulative Effects
15.7.1. This section assesses the effect of the Proposed Development and associated infrastructure in combination with the likely effect on archaeology and heritage arising from other developments in the area. It considers development that are either similar in nature or scale to the Proposed Development or within close proximity of it. The schemes outlined in Chapter 7: Assessment Methodology could have a cumulative effect with the Proposed Development and associated infrastructure on archaeology and cultural heritage.
15.7.2. None of the below ground archaeological features that have been identified are likely to be affected by these cumulative schemes. It is also expected that the
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cumulative schemes would implement good industry practice, which involves appropriate desk study, intrusive investigation where required, and archaeological monitoring in liaison with SGC and/or BCC. Where archaeological features are encountered the cumulative schemes are expected to generate a minor adverse effect; because each artefact is geographically distinct and separate, it is not expected that any cumulative effects greater than minor adverse would occur.
15.7.3. Once operational, the cumulative schemes will together lead to a more built up landscape, particularly when viewed from the setting of Blaise Castle and Kings Weston House. Although the stacks and possibly some of the other structures may be visible from these assets, given the general industrial nature of the area already, the recent history of the area being more industrial than now, and the distance of these sites from the heritage assets mentioned, it is not expected to increase the cumulative effect beyond minor adverse.
15.8. Impacts and Effects yet to be Determined
15.8.1. This section identifies any impacts and effects that have not yet been determined, or changes that are expected between writing this report and submission of the DCO application.
15.8.2. Any changes that lead to differing or new impacts and effects will be highlighted within the final ES, along with the reasons for the change.
15.8.3. It is also likely that the baseline conditions will change between the preparation of this PEI Report and the final ES. The Proposed Development Site is currently subject to excavation, top soil stripping, and levelling in certain areas in order for third parties to deliver the Spine Access Road and new channel for the Red Rhine, which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7: Assessment Methodology. A haul road is also being constructed through the middle of the Proposed Development Site to enable access by third party from the roundabout to the east of the Site to the Severnside Energy Recovery Centre to the west. These works onsite are being undertaken by other developers, under extant planning permissions and are separate to the Proposed Development.
15.8.4. Providing that the ground conditions are still intact following work onsite by the third parties, an archaeological evaluation exercise will be undertaken prior to issue of the final ES within the locations of below ground impact, as previously discussed.
15.8.5. The final ES will report on the baseline conditions considered relevant at the time of submission, or an agreed point of time shortly before, as well as any changed
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to the predicted magnitude of change or effects on archaeology and cultural heritage as a result of the changing baseline conditions.
15.9. References
Ref. 15-1 Department for Communities and Local Government (2012) National Planning Policy Framework
Ref. 15-2 Department for Communities and Local Government (2010). PPS5: Planning for the Historic Environment: Historic Environment Planning Practise Guide
Ref. 15-3 Institute for Archaeologists. (2012). Code of Conduct.
Ref. 15-4 English Heritage (2008) Conservation Principles, Polices and Guidance
Ref. 15-5 English Heritage (2011) The Setting of Heritage Assets
Ref. 15-6 Planning (Listed Buildings and Conservation Areas) Act 1990
Ref. 15-7 Planning and Compulsory Purchase Act 2004
Ref. 15-8 South Gloucestershire County Council (2013) Local Development Framework [Online]
Ref. 15-9 The Town and Country Planning (Environmental Impact Assessment) Regulations 2011
Ref. 15-10 Masser P Jones J McGill B (2005) Romano-British settlement and land-use on the Avommouth Levels
Ref. 15-11 McGill B (2001) Pucklechurch to Seabank Pipe Line Archaeological Programme Volume 2
Ref. 15-12 Everton, A., and Everton, R., 1980. ‘Romano-British occupation at Crook’s Marsh Farm, Avonmouth’, Bristol Archaeological Research Group Review 2, 57–8.
Ref. 15-13 BaRAS 1997. ‘Archaeological Watching Brief on the construction of 132 & 33KVoverhead electricity lines to Seabank Power Station, Hallen, Bristol’ (Bristol and Region Archaeological Services unpublished report, 263/1997, in South Gloucestershire SMR).
Ref. 15-14 BaRAS (1995) Land to the south of the Former Seabank Hydrcarbon Reforming Plant. Archaeological Desk Based Assessment
Ref. 15-15 BaRAS (1998) Seabank to Avonmouth Sewerage Works Pipeline. Archaeological Watching Brief
Ref. 15-16 BaRAS (1999) Seabank to Avonmouth Sewerage Works Pipeline. Archaeological Watching Brief
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Ref. 15-17 Stratascan (2001) Geophysical Survey at Smoke Lane, Rockingham, Avonmouth
Ref. 15-18 Russett, V, J, (1990) Archaeology of the Second Severn Crossing 1b
Ref. 15-19 Masser P Jones J McGill B (2005) Romano-British settlement and land-use on the Avommouth Levels
Ref. 15-20 Everton, A, and Everton, R, (1981) Romano-British Occupation at Crook’s Marsh Farm Avonmouth
Ref. 15-21 Robinson S Marvell A (1997) GGAT Project A 430 Junction G Archaeological Desk- Based Assessment
Ref. 15-22 McDonnel, R, (1989) Avon Levels Survey
Ref. 15-23 Smith A H (ed) (1964) Place names of Gloucestershire
Ref. 15-24 Aerial Photograph (CCC 11756/6238 ST 5279/1)
Ref. 15-25 Cotswold Archaeology, (2009) Land at Avonmouth Cultural Heritage Desk Based Assessment
Ref 15-26 Locock, M., and Lawler, M., 2000. ‘Moated enclosures on the North Avon Level: survey and excavation atRockingham Farm, Avonmouth, 1993–7’, Trans. B.G.A.S. 118, 93–122.
Ref 15-27 McGill, B., 2001. ‘Pucklechurch to Seabank Pipeline: Archaeological Programme, vols. 2 and 3’ (McGill Archaeological Consultants unpublished report in South Gloucestershire SMR).
Ref 15-28 Carter, SP, Jones, J and McGill, B 2003 Pucklechurch to Seabank pipeline: sediment stratigraphic and palaeoenvironmental data from the Avonmouth Levels. Archaeology in the Severn Estuary, 14, 69-86
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16. Ecology
16.1. Introduction
16.1.1. This chapter of the PEI Report addresses the potential ecological effects
predicted to arise as a consequence of the Proposed Development and
associated infrastructure.
16.1.2. This chapter describes the baseline conditions at the DCO Site and surrounding
area; potential direct, indirect and induced effects during the construction,
operational and decommissioning phases of the Proposed Development and
associated infrastructure; and any measures to avoid or mitigate predicted
adverse effects of the Proposed Development and associated infrastructure on
ecological receptors.
Consultation
16.1.3. A scoping request was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on the proposed structure, EIA
methodology and content of this PEI Report and subsequent ES. A summary of
stakeholder comments relevant to this chapter is provided in Table 16-1.
Table 16-1: Relevant Scoping Opinion Responses
Stakeholder Comment Response
Planning Inspectorate The potential impacts on internationally and nationally designated sites should be addressed as well as county level habitats and a number of locally designated sites
The range of statutory and non-statutory designated sites that have been considered are presented in Tables 16-6 and 16-7. The potential effects are assessed in section 16.5.
The ecology assessment should take account of the impacts on noise, vibration, air quality and water quality and cross reference should be made to the relevant technical chapters/appendices of the ES.
The assessment takes account of these other topics in section 16.5 and cross references to the relevant chapters.
Countryside Council for Wales (CCW)
The applicant will need to take the Severn Estuary international designations into account when assessing possible impacts from the proposal in the EIA. There are a number of other nationally and internationally important sites within 10km of the proposed sites, such as River Wye SAC, SSSI which is connected hydrologically to the Severn Estuary.
The potential effects on these international designations are addressed in the Habitats regulations Assessment, which is presented in Appendix K Part 1, Volume II of this PEI Report. The effects are also summarised in section 16.5.
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Stakeholder Comment Response
It is unclear if the 16 statutory sites found within 10km of the site include those in wales
The statutory sites include those in Wales and this is included in Appendix K Part 8, Volume II of this PEI Report.
The ES should contain sufficient information to allow all the Habitat Regulations Assessments to be carried out, including any appropriate assessments should they be required.
This is addressed within HRA screening report, Appendix K Part 1, Volume II of this PEI Report.
Marine Management Organisation
If direct cooling using water from the estuary is utilised, marine environmental impacts will need to be taken into account.
This option has since been discarded and therefore the consultation response is not addressed further in the PEI Report.
BCC The proposed electrical connection and its study corridor directly impacts on a Wildlife Network Site (WNS), Crook’s Marsh. Accordingly this area should be surveyed using extended phase 1 methodology.
The electrical connection has been modified since scoping so that it extends through or under the Seabank 1 & 2 site. This is discussed in section 16.3.
The proposed water pipeline has the potential to directly affect a number of Sites of Nature Conservation Importance (SNCIs) and WNS - this area should be surveyed using phase 1 methodology at the appropriate time of year and a method statement developed to minimise the impacts.
Baseline surveys of the cooling water pipeline are still being undertaken. Data collected at the time of preparation of the PEI Report is presented in section 16.5 under the heading ‘Other DCO land’. The assessment for the cooling water pipeline will be completed following completion of the surveys and reported in the final ES
The ecological chapter of the ES will need to include not only an extended phase 1 habitat survey of the land in question but also regularly repeated field surveys of the use of the fields by birds, especially wading birds and waterfowl which are qualifying interest feature birds of the Severn Estuary European Marine Sites.
The scope of surveys for wintering birds was discussed and agreed with Natural England. The methods are presented in section 16.3, and results in section 16.5 and Appendix K Part 4, Volume II.
NE It should be noted that the ponds at Bristol Waste Water Treatment Works are designated a SNCI.
This site is included in the scope of the assessment and details of it are presented in Appendix K Part 1, Volume II of this PEI Report. The assessment of any effects of the development will be presented in the final ES.
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Stakeholder Comment Response
The ES should consider the potential for birds to hit the overhead wires if overhead lines are installed.
Overhead lines are not part of the Proposed Development, as explained in Chapter 4: Project Description.
A habitat survey (equivalent to Phase 2) should be carried out across the development area. In addition, ornithological, botanical and invertebrate surveys should be carried out at appropriate times of the year, to establish whether any scarce or priority species are present.
Statutory consultees, including Natural England, Bristol City Council and South Gloucestershire Council were consulted on the scope of the surveys. Methods and timing of surveys is presented in sections 16.3 and 16.5.
It is important to consider the seasonal impacts of the development and avoid any noisy or disruptive activities in sensitive areas, for example laying pipes in winter months across known wintering bird habitat.
The potential for seasonal impacts is discussed for the Proposed Development site in sections 16.5. Appropriate control measures are presented in section 16.5. Effects arising from the cooling water pipeline will be more fully assessed in the final ES.
SGC It is considered important that the EIA takes account of the Cresswell report that included a review of the partially implemented historic ICI planning permission - 'the 57/58 consent'. Provided the proposed CCGT proposal accords with the strategy for new wetland habitat contained within the Cresswell report, there should be no significant effect on the Severn Estuary European Site (SPA/Ramsar).
The recommendations from the Cresswell report have been considered and used as the basis for specific mitigation measures proposed for the Proposed Development in section 16.5.
Other potential impacts on the ecological receptors or conservation objectives of the Severn Estuary SAC/SPA/Ramsar - such as noise, vibration, traffic, dust, lights or aerial or aquatic discharges - may need to be subject to their own HRA or Appropriate Assessment under the Habitat Regulations 2010.
These impacts are discussed in section 16.5 and the HRA Screening assessment presented in Appendix K Part 1, Volume II of this PEI Report.
EA Full consideration should be given to the Eels Regulations (2009) to ensure safe passage when proposing mitigation measures.
The requirements of the Eel Regulations (2009) is summarised in Appendix D, Volume II of this PEI Report. The occurrence of eels in Red Rhine is described in section 16.3.
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Stakeholder Comment Response
The Red Rhine may also support water voles and act as corridors for otter. As such, proposed survey work in the Spring should highlight any potential impacts on these species.
Surveys for water vole are in progress. An assessment of the impacts of the scheme on these receptors will be presented in the full ES.
Legislation and Planning Policy
16.1.4. An overview of planning policy relevant to this chapter is presented in Appendix
D, Volume II of this PEI Report. A summary of relevant legislation that has been
considered in this assessment is provided below:
• Birds Directive 2009/147/EC - prohibits activities that directly threaten
certain birds.
• The Conservation of Habitats and Species Regulations 2010 - projects
can only be permitted having ascertained that there will be no adverse
effect on the integrity of 'European sites'. Projects with predicted adverse
changes on European sites may still be permitted if there are no
alternatives to them and there are Imperative Reasons of Overriding
Public Interest (IROPI) as to why they should go ahead.
• The Wildlife and Countryside Act 1981 – makes it an offence (with
exception to species listed in Schedule 2) to intentionally:
o Kill, injure, or take any wild bird;
o Take, damage or destroy the nest of any wild bird while that nest
is in use or being built; or
o Take or destroy an egg of any wild bird.
The Act also makes it an offence (subject to exceptions) to intentionally
kill, injure or take any wild animal listed on Schedule 5, and prohibits
interference with places used for shelter or protection, or intentionally
disturbing animals occupying such places. Species included in Schedule
5 are:
o Great crested newt (Triturus cristatus)
o Water Vole (Arvicola amphibius)
o Badger (Meles meles)
o Slow worm (Anguis fragilis)
o Grass snake (Natrix natrix)
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• The Countryside and Rights of Way Act 2000 (CRoW) - amends the
species provisions of the Wildlife and Countryside Act 1981,
strengthening the legal protection for threatened species.
• Protection of Badgers Act 1992 - makes it an offence, except as
permitted by or under this Act, to wilfully kill, injure or take, or attempt to
kill, injure or take, a badger.
• Hedgerow Regulations 1997 - It is against the law to remove ‘important’
hedgerows without permission.
• Natural Environment and Rural Communities Act 2006 lists for England
(NERC Act Section 41) - lists species and habitats of principal
importance for nature conservation. The list of Species of Principle
Importance describes the biological resources of the UK at a national
level.
16.2. Assessment Methodology and Significance Criteria
Scope of Ecological Impact Assessment
16.2.1. The methodology and assessment broadly follows guidance published by the
Chartered Institute of Ecology and Environmental Management (CIEEM) (Ref.
16-1).
16.2.2. The spatial scope of the assessment includes all ecological receptors with
potential to be directly or indirectly affected by the Proposed Development, and
associated infrastructure, including:
• Statutory sites designated for nature conservation value within 10km and
non-statutory sites within 1km of the Proposed Development Site and
Other DCO land (the desk study for the Proposed Development Site was
undertaken to a distance of 1.5km from the centre of the Site); and
• Legally protected or otherwise notable species currently onsite or
considered likely to be affected by works onsite. For the Other DCO
Land, the surveys incorporated 100m wide corridor, which included the
30m proposed cooling water pipeline corridor plus an additional 35m
either side. This was considered a reasonable buffer based on the
habitats found to be present and receptor sensitivity.
16.2.3. The temporal scope of the assessment is based on the programme described in
Chapter 5: Enabling Works and Construction, in which the assumed start date for
the enabling works has been assumed to be 2017 with the Proposed
Development assumed to become operational in 2021. The predicted ecological
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baseline conditions at the start of construction are described in paragraphs
16.3.64 to 16.3.74 and evaluated in Table 16-7.
16.2.4. An Extended Phase 1 habitat survey was undertaken to map all broad habitats
on the Proposed Development Site to record dominant and frequent plant
species, and to assess potential for protected species. A habitat survey has been
carried out along the proposed cooling water pipeline corridor to identify which
protected species surveys are required; the Extended Phase 1 habitat survey for
the pipeline corridor was undertaken during spring 2014 and is presented in
Appendix K Part 9, Volume II of this PEI Report.
16.2.5. As a result of the initial surveys, the following protected species surveys were
conducted on both the Proposed Development Site and Other DCO Land
(excluding the proposed electrical connection corridor which is routed through the
existing Seabank 1 & 2 station):
• Breeding birds;
• Non-breeding birds;
• Bat roost;
• Bat activity;
• Badger;
• Water vole;
• Otter;
• Reptiles;
• Great crested newt; and
• Invertebrates.
16.2.6. It should be noted the scope of the wintering bid survey was based on a
preliminary project design that considered the possibility of installing a cooling
water pipeline into the estuary (which was later discarded); hence it led to a
greater survey area than was required for the Proposed Development, including
surveys of the Severn estuary foreshore in order to allow for the assessment of
any impacts on wintering bird populations for which the site is designated as a
SPA. The selection of hybrid cooling removed the need for shoreline works and is
discussed in more detail in Chapter 6: Project Alternatives of this PEI Report.
Desk Study
16.2.7. Existing data regarding designated sites and protected or otherwise notable
species within 1km of the site boundary were obtained from NE’s Nature on the
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map website, the Multi-agency Geographic Information for the Countryside
(MAGIC) website and the Bristol Regional Environmental Records Centre
(BRERC). This search radius was extended to 10km for statutory designated
sites in line with EA criteria for assessment of power station projects with
potential for emissions to air or water, and in line with consultation responses
from CCW.
16.2.8. Owing to the presence of the Severn Estuary SPA and Ramsar site 400m west of
the Proposed Development Site, British Trust for Ornithology (BTO) Wetland Bird
Survey (WeBS) core count and low tide data were also requested.
Field Survey Methods
Extended Phase 1 Habitat survey
16.2.9. An Extended Phase 1 habitat survey was conducted on 24 April 2012, using the
standard Phase 1 methodology devised by the Joint Nature Conservation
Committee (Ref. 16-2) to map the broad habitats present within the Proposed
Development Site.
16.2.10. The survey was extended according to the methodology described by the
Institute of Environmental Assessment (Ref. 16-3) to include targeted searches
for signs of protected species.
16.2.11. Target notes were made to provide supplementary information on species
composition, topography and evidence of management. Notes were also taken of
any evidence of the presence of protected or notable fauna (Ref. 16-4). The
methodology and results of the survey are reported in full in Appendix K Part 2,
Volume II of this PEI Report.
16.2.12. The findings of the 2012 survey were verified in subsequent surveys during 2013.
16.2.13. A full extended Phase 1 survey of the Other DCO Land was undertaken during
spring 2014, as presented in Appendix K Part 9, Volume II of this PEI Report.
This survey has identified the presence or possibility of protected and notable
species, requiring further survey, and the findings of these surveys will be
included in the final ES. It has been concluded that as the electrical connection
for the DCO application will comprise underground cables or a low rise cable rack
across land already developed for Seabank 1 & 2, then this will not require
ecological scoping.
Species Surveys
16.2.14. The survey methods utilised for each of the species surveys undertaken are
summarised below and described in full in the relevant technical reports, in
Appendix K Parts 3 to 7, Volume II of this PEI Report. The reports are as follows:
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• Appendix K Part 2: Phase I Habitat Survey for the Proposed
Development Site;
• Appendix K Part 3: Bat Surveys;
• Appendix K Part 4: Wintering Bird Surveys;
• Appendix K Part 5: Breeding Bird Surveys;
• Appendix K Part 6: Amphibian Surveys;
• Appendix K Part 7: Reptile Surveys.
16.2.15. These survey reports all cover the Proposed Development Site, but omit the
Other DCO Land. The need for the surveys to be extended to include the Other
DCO Land will be confirmed following the Extended Phase I Habitat Survey;
where it is considered necessary based on current information, the intention to
carry out the surveys is highlighted in the relevant sections later in this chapter.
Bats
16.2.16. A tree bat roost potential survey was undertaken on the three suitable trees
within the Proposed Development Site. Trees were surveyed for the presence or
potential for roosting bats by inspecting the trees for signs of bat occupancy,
such as presence, droppings, scratch marks, staining and feeding remains.
16.2.17. No trees with potential to support roosting bats occur within the Other DCO Land
and therefore roost surveys were scoped out for this part of the DCO Site.
16.2.18. Five evening bat activity surveys and four dawn surveys were undertaken to
identify habitat usage and species composition on both the Proposed
Development Site and Other DCO Land. The surveys followed repeatable set
transects and standard protocol for recording individual bat species and covered
the peak of dusk and dawn bat activity. Heterodyne and frequency division
detectors were used. Sound analysis was also used to further analyse
recordings.
Breeding Birds
16.2.19. Breeding birds were assessed over the course of three survey visits that covered
both the Proposed Development Site and Other DCO Land during the peak bird
breeding season (March to June) in 2013. Given the size of the DCO Site, each
full site visit was split over two separate days.
16.2.20. Surveys followed the standard British Trust for Ornithology Breeding Bird Survey
method (Ref. 16-5). A survey route was taken that allowed observation of all
major areas of habitat within the proposed areas of activity, and the surrounding
habitats.
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Non-breeding Birds
16.2.21. Bird surveys initially included the Proposed Development Site and the Severn
Estuary, since the preliminary project design considered including a cooling water
pipeline extending into the estuary; this option was subsequently discarded in
favour of hybrid cooling using water from Bristol WWTW. To record non-breeding
birds, visits were made between October 2012 and March 2013 and again from
August 2013 to October 2013 inclusive. The scope of the surveys was discussed
and agreed in advance with NE, SGC and BCC. Surveys were designed to
record birds at different tidal states, during day and night, and neap and spring
cycles.
16.2.22. On each visit to the Proposed Development Site, the surveyor positioned
themselves at a vantage point and observed birds using appropriate equipment
from this fixed position for the hour up to high or low tide. During the second hour
of survey, the surveyor slowly walked the survey area, keeping toward the
perimeters, primarily to flush cryptically patterned or stationary birds that might
escape detection during the first hour of survey.
16.2.23. For estuary counts, the surveyor was positioned at a fixed point for the daytime
surveys. During nocturnal surveys, the same approach was undertaken as for
inland surveys, namely a first hour of fixed point surveying, followed by an
attempt to walk a transect toward more distant species.
16.2.24. The surveys were undertaken in a range of weather conditions in order to
determine the usage of the survey area in relation to factors such as strong winds
and snow that might affect local distribution of any birds that could potentially use
the estuary and or Proposed Development Site.
Reptiles
16.2.25. To record reptiles, eighty artificial refugia were placed in appropriate locations
across the Proposed Development Site. A total of seven visits were undertaken
between May and October 2013 where all artificial refugia were checked for
basking or sheltering reptiles under suitable temperature and weather conditions.
Hand searches for reptiles were also undertaken including searching beneath
debris already occurring on Site.
Great Crested Newts
16.2.26. Amphibian surveys were undertaken on the Proposed Development Site between
May and June 2013. Four water bodies were surveyed, by a range of methods:
placement of 160 bottle traps, torchlight surveys, and egg searches. Where
possible, for all amphibians identified during the survey the frequency, sex, and
life stage were recorded.
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16.2.27. Amphibian surveys of the cooling pipeline route within the Other DCO Land
commenced in May 2013 but could not be completed within the 2013 survey
season. They will be completed in April 2014 and included in the final ES.
Terrestrial and Aquatic Invertebrates
16.2.28. Terrestrial and aquatic invertebrate surveys were undertaken in suitable habitats
on the Proposed Development Site.
16.2.29. An initial scoping survey was carried out along the proposed cooling water
pipeline corridor. As a result, eight areas were chosen for further surveys since
they had potential to support invertebrates of conservation importance.
16.2.30. A variety of terrestrial invertebrates survey techniques were undertaken including
beating, sweep netting, vacuum sampling, splash sampling and light trapping.
16.2.31. Aquatic invertebrates were surveyed by using hand searching, pitfall trapping and
visual searching. A total of eighteen site visits were undertaken between May –
October 2013. Further analysis of samples will be reported in the final ES.
Significance Criteria
Value of Resource / Receptor
16.2.32. An ecological resource / receptor is defined as a site / area / species of nature
conservation value. Each site / area may have more than one feature of value
that it supports (for example different habitats or populations and/or assemblages
of species). Individual ecological resources / receptors and the features that
comprise them are evaluated according to generally accepted criteria, including
designation and protection status. With reference to published Institute of
Ecology and Environmental Management (IEEM) guidelines (Ref. 16-1) to attain
each level of value / importance, an ecological resource / receptor or one of the
features should meet the criteria set out in Table 16-2 below.
16.2.33. In some cases, professional judgement may be applied to increase or decrease
the allocation of specific value. This judgement is based on consideration of the
following additional criteria:
• Population trends;
• Sustainability of resource / receptor;
• Representativeness;
• Potential for substitution/re-creation;
• Position in the ecological unit;
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• Biodiversity; and
• Intrinsic value to stakeholders.
Table 16-2: Valuation of Ecological Receptors
Sensitivity of Receptor Example Criteria
Very High
(international)
An internationally designated site or candidate/proposed site i.e. SPA, proposed SPA (pSPA), SAC, candidate SAC (cSAC) and/or Ramsar site.
A large area of a habitat listed in Annex I of the Habitats Directive or smaller areas of such habitat which are essential to maintain the viability of the larger whole.
Large population of an internationally important species or site supporting such a species (or supplying a critical element of their habitat requirement) ;
UK Red data book species that is listed as occurring in 15 or fewer 10km squares in the UK, that is of unfavourable conservation concern in Europe or of uncertain conservation status or global conservation concern in the NERC species lists; or
Species listed on Annex IV of the Habitats Directive.
High
(National)
A nationally designated site i.e. SSSI or National Nature Reserve (NNR) or a discrete area which meets the selection criteria for national designation (e.g. SSSI selection criteria).
An area of a priority habitat identified in Section 41 of the Natural Environment and Rural Communities (NERC) Act 2006 which constitutes a significant proportion of the UK resource of that habitat (or smaller areas of such habitat, which are essential to maintain the viability of the whole).
Populations of a nationally important species or site supporting such a species (or supplying a critical element of their habitat requirement) which constitutes more than 1% of the national population of that species i.e.: Species listed on Schedules 5 and 8 of the WCA (1981); Other UK Red Data Book species; Other species listed as occurring in 15 or fewer 10km squares in the UK; or Sites supporting 1% or more of a national population of a species.
Medium
(County)
Local Nature Reserves, Sites of Importance for Nature Conservation (SINCs).
A viable area of habitat identified in the County Biodiversity Action Plan (BAP).
Substantial populations of the following species:
Species listed in a County/Metropolitan ‘red data book’ or Section 41 of the NERC Act 2006 on account of its rarity/localisation in a county context; or
Sites supporting 1% or more of a county population.
Low
(Borough)
Viable areas of habitat identified in Section 41 of the NERC Act 2006 but which are not large enough to meet the criteria for national or county value.
Sites/features which are scarce within the Borough or which appreciably enrich the Borough habitat resource.
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Sensitivity of Receptor Example Criteria
Small but sustainable populations of a legally protected species or one that is notable for some other reason, e.g. that it is featured in a county BAP or the NERC species lists.
Sites/populations, which appreciably enrich the District/Borough habitat resource (e.g. moderately species-rich hedgerows).
Very Low Less than Low value, or with negligible ecological value.
16.2.34. It should be recognised that even though a site may have no apparent ecological
features, it may perform an ecological function. For example, a site may act as a
‘stepping stone’ with the surrounding landscape.
16.2.35. Protected species are assessed independently of legal protection. For example,
a site which has bat species foraging above it is not automatically of international
value (and therefore analogous with a SAC). Instead, such a site may be
assessed as having value in a Borough or County context.
Magnitude of Change
16.2.36. Magnitude of change results from any factor which may result in a change to the
existing nature conservation resource / receptor. The criteria utilised to
determine the magnitude of impact are identified in Table 16-3. These criteria are
informed by the IEEM (Ref. 16-1) guidelines and have been developed in house
by experienced ecologists and EIA specialists.
Table 16-3: Magnitude of Change
Magnitude of Change
Description
Very High
Landtake of a habitat or feature, if it occurs, may be greater than 30%. Where changes are indirect, disruption of ecosystem functioning occurs, with loss of species and loss of diversity. Changes may be long-lasting or permanent, particularly if loss or major alteration of wildlife habitat occurs. Recovery, if possible, is likely to take more than three years.
High
Landtake of a habitat or feature, if it occurs, may be greater than 20%. Where changes are indirect, disruption of ecosystem functioning occurs, with loss of species and loss of diversity. Changes may be long-lasting or permanent, particularly if loss or major alteration of wildlife habitat occurs. Recovery, if possible, is likely to take more than three years.
Medium
Landtake of a habitat or feature, if it occurs is less than 20% of the area. Where changes are indirect, qualitative change occurs. The abundance of some of the more sensitive species may be reduced. Changes in habitat may be longer lasting. Change is reversible, or nearly so, although recovery of changes other than landtake may take up to three years following cessation of factors causing change.
Low Landtake of a habitat or feature, if it occurs, affects less than 5% of the area. Where indirect changes occur, some changes in species abundance may occur, but the change is reversible. Full recovery is likely in the short
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Magnitude of Change
Description
term, probably within a year, following the cessation of factors causing change.
Very Low/ Negligible
With ecological resources / receptors it is often not possible to state categorically that there will be no change, but this category is used when the chance of any change is very low and if it occurs it is well below the level of detection.
Significance of Effect
16.2.37. Taking the value of each resource / receptor and magnitude of change into
account, these criteria can be combined to produce an overall evaluation of
whether an effect is significant. This is indicated in Table 16-4 below.
16.2.38. An ecological effect results from a change upon a resource / receptor. Direct
effects on resources / receptors resulting from activities that are an integral part
of the Proposed Development have been considered in this ecological
assessment. In addition, indirect, secondary and cumulative effects have been
examined. The duration of the effect (i.e. permanent or temporary and short,
medium or long-term) and sensitivity of a resource / receptor (to a specific effect)
have also been taken into account.
Table 16-4: Classification of Effects
Sensitivity of receptor
Magnitude of Change
Very High
High Medium Low Very
Low/Negligible
Very High Major Major /
Moderate Moderate
Moderate / Minor
Minor
High Major /
Moderate Moderate
Moderate / Minor
Minor Minor /
Negligible
Medium Moderate Moderate
/ Minor Minor
Minor / Negligible
Negligible
Low Moderate
/ Minor Minor
Minor / Negligible
Negligible Negligible
Very Low Minor Minor /
Negligible Negligible Negligible Negligible
16.2.39. Where necessary professional judgement has been applied to the standard
outputs of the decision matrix (as shown in Table 16-4) in order to ensure the
resultant overall effect is considered consistent with the definitions provided in
Table 16-5.
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Table 16-5: Definitions of Effects
Classification of Effect Description
Major An effect which in isolation could have material influence on the decision making process and is clearly significant.
Major/Moderate An effect which could have some material influence but requires professional judgement to determine this, and which is significant.
Moderate An effect which on its own could have some influence on decision making, particularly when combined with other similar effects, and which may be considered significant.
Moderate/Minor An effect which may be likely to have some influence on decision making, professional judgement required to determine.
Minor An effect which on its own is likely to have a minor influence on decision making but when combined with other effects could have a more material influence
Minor/Negligible
An effect which could have either a minor or negligible effect which requires professional judgement to differentiate
Negligible An effect that is likely to have a negligible influence, irrespective of other effects
16.2.40. Significant effects occur where valuable or sensitive resources, or numerous
receptors, are subject to changes of considerable magnitude. Effects are unlikely
to be significant where low value or non-sensitive resources, or a small number
of receptors, are subject to minor changes.
16.2.41. Major, moderate/major, or moderate effects are regarded as significant. Where
significant effects occur, the scale of the effect is also considered on a
geographical scale (i.e. International, National, Regional, County, Borough or
Local).
Level of Confidence in Predictions
16.2.42. IEEM (Ref. 16-1) also recommends consideration of the likelihood that a
change/activity would occur as predicted and the degree of confidence in the
assessment of the change on ecological structure and function. A four point scale
as recommended by IEEM is adopted for use in this ES:
• Certain/near-certain: probability estimated at 95% or higher;
• Probable: probability estimated above 50% but below 95%;
• Unlikely: probability estimated above 5% but below 50%; and
• Extremely unlikely: probability estimated at less than 5%.
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Key Parameters for Assessment
16.2.43. The proposed envelope (‘Rochdale Envelope’) parameters outlined in Chapter 4:
Project Description do not significantly affect the input parameters utilised in
either the operational or construction ecology assessments, and consequentially
the outcome of these assessments will not vary. Therefore the assessment
adopts conservative (worst case) values where assumptions are necessary.
16.2.44. Regarding the main building sizes, it is assumed that all vegetation within the
main works area will be cleared to facilitate construction, therefore from an
ecological perspective there is not considered to be a difference in the impact
depending on the final sizing and layout of buildings.
16.3. Baseline Conditions
16.3.1. A summary of the results of the desk study and field surveys undertaken to
establish the baseline conditions for the Proposed Development Site and Other
DCO Land is presented in this section. Full details of the desk study and field
surveys are presented in the following appendices:
• Appendix K Part 2: Phase I Habitat Survey for the Proposed
Development Site;
• Appendix K Part 3: Bat Surveys;
• Appendix K Part 4: Wintering Bird Surveys;
• Appendix K Part 5: Breeding Bird Surveys;
• Appendix K Part 6: Amphibian Surveys; and
• Appendix K Part 7: Reptile Surveys.
Statutory Designated Sites for Nature Conservation
16.3.2. Figure 16-1, Volume III of this PEI Report illustrates the designated sites that lie
within 10km of the Proposed Development Site.
16.3.3. No statutory designated sites for nature conservation occur within or directly
adjacent to the Proposed Development Site. The nearest statutory designated
site is the Severn Estuary which is situated approximately 400m west of the Site.
16.3.4. There are twenty-eight statutory designated sites for nature conservation within
10km of the Proposed Development Site / DCO Site. There is one Ramsar site,
two SACs, one SPA, seventeen SSSIs, one NNR and seven Local Nature
Reserves (LNR). Some sites have been given multiple designations of which
there are three additional SSSI’s and one SAC. The reasons for their designation
and locations relative to site are detailed in Appendix K Part 8, Volume II.
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16.3.5. There are no proposed SACs (pSACs) or Marine Conservation Areas within the
study area.
Non-Statutory Designated Sites for Nature Conservation
16.3.6. Figure 16-2, Volume III of this PEI Report illustrates the non-statutory wildlife
sites located within 1km of the Proposed Development Site and associated
infrastructure.
16.3.7. There are fourteen non statutory designated sites for nature conservation within
1km of the DCO Site. All of which are designated as Sites of Nature
Conservation Importance (SNCI) and two of which are also designated as Avon
Wildlife Trust Site (AWTS). The reasons for their designation and locations
relative to site are detailed in Appendix K Part 8, Volume II.
Protected and Notable Species Records
16.3.8. Records of protected and/or otherwise notable fauna and flora species recorded
within 1.5km of the centre of the Proposed Development Site are presented in full
in the extended Phase 1 habitat survey report (Appendix K Part 2, Volume II).
The information is summarised below.
16.3.9. The only protected species record on the DCO Site was one record of Marsh-
mallow (Althaea officinalis) which was found to occur within the Other DCO Land,
within the proposed cooling water pipeline corridor.
16.3.10. A number of water vole (Arvicola terrestris) recordings have occurred within
Crook’s Marsh and the Red Rhine, less than 1.5km from the centre of the
Proposed Development Site, and 1km from the associated infrastructure.
16.3.11. There are a number of records of badger (Meles meles) within 1km of the Site
boundary, the nearest of which was 820m from the centre from the Proposed
Development Site and 200m from the associated infrastructure.
16.3.12. Protected bird species have been recorded within 1.5km of the centre of the
Proposed Development Site, including kingfisher (Alcedo atthis), and peregrine
(Falco peregrinus). Bird species of conservation concern have been recorded
within approximately 1km of the DCO Site, including Skylark (Alauda arvensis),
Common kingfisher (Alcedo althis), Pintail (Anas acuta), House sparrow (Passer
domesticus), Tree sparrow (Passer montanus), common Starling (Sturnus
vulgaris) and Dunnock (Prunella modularis).
16.3.13. There are several records of butterflies and moths, which are notable species
within 1.5km of the centre of the Proposed Development Site. These include
Small heath (Coenonympha pamphilus), White-letter hairstreak (Satyrium w-
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album), Cinnabar (Tyria jacobaeae); Rosy rustic (Hydraecia micacea), Latticed
heath (Chiasmia clathrata); and Blood-vein (Timandra comae). The Moss Carder-
bee (Bombus (Thoracombus) muscorum) has also been recorded within the
study area.
16.3.14. Several other notable invertebrate species have also been recorded within the
study area, mainly associated with the aquatic habitats, for example several
species of water beetle. A total of 3 invertebrate species have been recorded
within 1km of the proposed cooling water pipeline corridor, including a micro-
moth (Agonopterix arenella), a fly (Anagnota bicolor) and mouse moth
(Amphipyra tragopoginis) listed under the NERC S41.
16.3.15. Five notable plant species have been recorded within 1km of the Proposed
Development Site and proposed cooling water pipeline corridor. Sneezewort
(Achillea ptarmica) and Pyramidal orchid (Anacamptis pyramidalis) are listed
under the International Union for Conservation of Nature (IUCN) red list. Marsh-
mallow (Althaea officinalis) and Smooth Rupture-wort (Herniaria glabra) are
classified as rare species and Three-lobed Water-crowfoot (Ranunculus
tripartitus) is listed under Section 41 of NERC, and classified as endangered.
16.3.16. Records of amphibians and reptiles occur from within 1.5km of the centre of the
Proposed Development Site, including great-crested newt, grass snake and slow-
worm. No records of amphibians and reptiles have been recorded within 1km of
the proposed cooling water pipeline corridor.
16.3.17. There are no records of bats within or immediately adjacent to the Proposed
Development Site or DCO Site, however there are records of bats roosts situated
within 10km of the DCO Site which are utilised by greater horseshoe bats
(Rhinolophus ferrumequinum) and lesser horseshoe bats (Rhinolophus
hipposideros) which are listed on Annex II of the Habitat Directive and for which
the Avon area is considered a national stronghold for this species. Lesser
horseshoe bats are also listed as Priority species on the South Gloucestershire
BAP. The closest greater horseshoe bat roost is approximately 7km south of the
Proposed Development Site. The closest lesser horseshoe roost record
(hibernation roost) is located approximately 4.5km south of the Proposed
Development Site.
16.3.18. The greatest concentration of roosts is situated to the south of the Proposed
Development Site towards the Avon Gorge area. Species which have been
recorded within 10km of the Proposed Development Site include: Noctules
(Nyctalus noctula); Leisler’s (Nyctalus leisleri), Serotine (Eptesicus serotinus),
Common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle (Pipistrellus
pygmaeus) and unidentified pipistrelle species, Brown long-eared (Plecotus
auritus), Daubenton’s (Myotis daubentonii) and Unidentified myotis species
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(Myotis spp.). The closest bat activity records to the site are approximately 3km.
Barbastelle bat (Barbastella barbastellus) activity has been recorded in Ashton
Court Estate. This is a rare species listed on Annex II of the Habitats Directive.
Field Surveys
16.3.19. Baseline information arising from the surveys is presented in summary below first
for the Proposed Development Site and then for the proposed cooling water
pipeline corridor. Full descriptions and data from each survey are presented in
Appendices K Part 2 to Part 8, Volume II of this PEI Report.
Extended Phase 1 Habitat Survey
16.3.20. The technical report for the Extended Phase 1 Habitat survey is included within
Appendix K Part 2, Volume II of this PEI Report. Summary descriptions of the
habitats are provided below, with their value/sensitivity based on Table 16-2.
Figure 16-3, Volume III of this PEI Report illustrates the habitat features found
within the Proposed Development Site.
16.3.21. The Proposed Development Site largely consists of grazing land interspersed
with rhines and patches of scrub. The patches of scrub present onsite are a
common habitat in the wider area and support a low species diversity. The scrub
habitat is therefore considered to be of Low (Borough) value.
16.3.22. A small area of immature elm woodland onsite is species poor and does not meet
the criteria for inclusion under the Woodland Priority Habitat within the SGC BAP.
The habitat however increases the structural diversity of the Proposed
Development Site and is therefore considered to be of Low (Borough) value
within the context of the site.
16.3.23. Three individual mature trees on-site increase the structural diversity of the
Proposed Development Site, and the deadwood habitats which they contain are
otherwise absent from the remainder of the Site. This habitat is therefore
considered to be of Low (Borough) value within the context of the Site.
16.3.24. Areas of semi-improved grassland occur towards the northwest of the Proposed
Development Site, and in a strip to the south of the Red Rhine. They are
considered to be of Low (Borough) value within the context of the Proposed
Development Site. The remaining grassland habitat within the Proposed
Development Site boundary is classified as poor semi-improved due to low
species diversity. This habitat is considered to be of Very Low value.
16.3.25. A small area of tall ruderal habitat type is present within the Proposed
Development Site. This is a common habitat in the wider area and supports a low
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species diversity. This habitat within the Proposed Development Site is
considered to be of Very Low value.
16.3.26. The water bodies, particularly those which are permanent features, increase the
biodiversity value of the study area. The Red Rhine currently crosses the centre
of the Proposed Development Site in an east to west direction and discharges
into the Severn Estuary at New Pill Gout. A number of other rhines cross the
Proposed Development Site, the largest of which, the Crook’s Marsh Stream,
drains into the Red Rhine from the south. Chapter 14: Flood Risk, Hydrology and
Water Resources provides further details of the drainage of the site and the wider
Red Rhine catchment.
16.3.27. Rhines are a habitat featured within the SGC BAP, although the rhine system
onsite is not considered to be sufficiently large to justify valuation at Medium
(County) level, based on the criteria presented in Table 16-2, and therefore a
Low (Borough) value has been attributed to them. Their value as a habitat for
protected species may be greater and this will be informed by further survey.
16.3.28. Hedgerows are Priority Habitats within the UKBAP and SGC BAP. There is a
single hedgerow onsite, which is considered to have poor diversity. Taking this
into account the hedgerow is therefore considered to be of Low (Borough)
conservation value.
16.3.29. The mosaic of habitats on the Proposed Development Site means that as a
whole the value of them is higher than the individual elements alone. The
interconnected nature of these lead to them being considered as of Medium
(County) conservation value.
Extended Phase 1 Habitat Survey – Other DCO Land
16.3.30. The technical report for the Extended Phase 1 Habitat survey is included within
Appendix K Part 9, Volume II of this PEI Report.
16.3.31. Habitats within the proposed cooling water pipeline corridor consisted of a range
of small parcels of land associated with the linear nature of the site, comprising
hardstanding, dense continuous scrub, scattered scrub, tall ruderal, semi-
improved neutral grassland, improved grassland, amenity grassland, marshy
grassland, standing water, rhines, tree lines, ornamental screening, hedge and
trees, tree-lines, scattered broadleaved trees, broadleaved plantation woodland,
semi-natural broadleaved woodland, industrial units, bridges and culverts.
16.3.32. The value of the habitats is primarily associated with their potential to support
protected or notable species, for which surveys are ongoing. The baseline data
for these, together with potential effects of the DCO Application, and any
mitigation or residual effects will be reported further in the ES.
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Protected or Notable Species Potential
16.3.33. Based on the Phase 1 Habitat Survey the Proposed Development Site was
considered to have potential to support a number of protected species including
some, such as badger, otter, water vole, and bats, which receive statutory
protection. Habitats suitable for these species/faunal groups are summarised in
Table 16-6 below.
Table 16-6: Habitat Potential for Protected Species and Other Fauna within the Proposed
Development Site
Species Habitat potential
Badger Spoil heaps in a number of locations, notably the northern boundary of the site. Foraging paths throughout the Site. Species specific surveys have therefore been undertaken.
Otter Rhines may provide foraging habitat and commuting routes to Severn Estuary. Species specific surveys have therefore been undertaken.
Water vole Wet rhines onsite, particularly Red Rhine, provide good quality water vole habitat. Species specific surveys have therefore been undertaken.
Dormice No suitable habitat present, therefore no further surveys have been undertaken.
Bats Waterbodies, scrub and grassland on-site provide suitable foraging and commuting habitat for bats. The 3 mature trees at the western end of the Proposed Development Site provide some suitable roosting habitat. Species specific surveys have therefore been undertaken.
Breeding birds Scrub, grassland and waterbodies provide suitable nesting habitat for breeding birds (including ground nesting birds and water fowl) and wintering birds. Species specific surveys have therefore been undertaken.
Amphibians (including great crested newt)
Standing waterbodies (ponds and ditches) provide suitable habitat for amphibians. The rhines have limited potential for this species. Species specific surveys have therefore been undertaken.
Reptiles All habitats on-site are suitable for use by common species of reptiles, e.g. slow worms, grass snakes, common lizards and adders. Suitable habitat is present to support these species in both summer and winter (during hibernation). Species specific surveys have therefore been undertaken.
Terrestrial and aquatic invertebrates
Mosaic of standing water and scrub offers suitable habitat for both aquatic and terrestrial invertebrates. Species specific surveys have therefore been undertaken.
Flora Habitats on-site are common and widespread. Potential to support protected or notable species of flora is low. No further surveys have therefore been undertaken
Species Specific Surveys
16.3.34. The following section summarises the results of species specific surveys
undertaken of the Proposed Development Site and Other DCO Land during
2013, and indicates where further surveys will be undertaken during 2014. Full
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details of the surveys, including methodology, results and raw data are presented
in Appendices K Parts 2 to 8, Volume II of this PEI Report.
Bats – Roost Potential and Activity on Proposed Development Site
16.3.35. A group of three mature ash (Fraxinus excelsior) trees were identified to have the
potential to support roosting bats onsite. No evidence of bats using these trees
was found from either the inspections or the emergence/re-entry surveys.
16.3.36. The activity survey results and analysis of bat recordings suggests that six bat
species - common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle
(Pipistrellus pygmaeus), noctule (Nyctalus noctula), serotine (Eptesicus
serotinus), Brandt’s (Myotis brandti) and Leisler’s (Nyctalus leisleri) were
recorded using the Proposed Development Site across both transects in low
numbers from the activity surveys.
Bats – Activity on the Other DCO Land
16.3.37. On the proposed cooling water pipeline corridor common pipistrelle, soprano
pipistrelle and noctule were recorded foraging above the group of ponds
hydrologically linked to the Salt Rhine, southwest of the Fire and Rescue Training
Centre, commuting and foraging along Moorend Farm Avenue and the lane to
the west of the Bristol WWTW. Common pipistrelle was recorded commuting
above Rhines to the southwest of the Proposed Development Site.
16.3.38. Myotis species (sound analysis indicated Brandt’s) were recorded foraging on the
proposed cooling water pipeline corridor close Moorend Farm Avenue.
Breeding Birds - Proposed Development Site
16.3.39. No species on the EU Wild Birds Directive Annex 1 and Wildlife and Countryside
Act Schedule 1 were recorded on the Proposed Development Site.
16.3.40. Four wild bird species that are red listed as birds of conservation concern within
the UK and were breeding, likely to be breeding, or had potential to be breeding
onsite were skylark (Alauda arvensis), lapwing (Vanellus vanellus), song thrush
(Turdus philomelos) and linnet (Carduelis cannabina). Of these, all except skylark
were confirmed or were considered likely to be breeding on the Red Rhine-
Ableton Lane sector of the Proposed Development Site and surrounding land.
Skylark had potential to be breeding at this location.
16.3.41. A pair of lapwing was exhibiting nesting behaviour just outside of the Proposed
Development Site boundary. Lapwing has declined as a breeding species by
over 50% in the past 25 years.
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16.3.42. Singing song thrush was recorded and is listed as a bird of conservation concern
due to a decline in the breeding population of greater than 50% since 1969
(although there are over 1.1 million pairs). Linnet is red-listed for the same
reason and was confirmed as breeding. There are over 500,000 pairs in the UK.
Skylark has declined by greater than 50% as a breeding species since 1969.
16.3.43. Three species confirmed or likely to be breeding on the Proposed Development
Site that have ‘amber’ Bird of Conservation Concern (BOCC) status were
dunnock (Prunella modularis), common whitethroat (Sylvia communis) and reed
bunting (Emberiza schoeniclus).
16.3.44. Local BAP species recorded during surveys on or adjacent to the Proposed
Development Site were skylark, linnet, reed bunting, dunnock, song thrush and
lapwing.
Breeding Birds - Other DCO Land
16.3.45. Cetti’s warbler (Cettia cetti), a species listed on the EU Wild Birds Directive
Annex 1 and Wildlife and Countryside Act Schedule 1, was heard singing from
marginal vegetation at lagoons on the Bristol WWTW site.
16.3.46. Three species that have ‘red’ Bird of Conservation Concern (BOCC) status were
recorded; skylark, song thrush and linnet were also confirmed as breeding along
the proposed cooling water pipeline corridor. Fourteen species confirmed or likely
to be breeding along the proposed cooling water pipeline corridor that have
‘amber’ BOCC status were mallard (Anas platyrhynchos), shelduck (Tadorna
tadorna), gadwall (Anas strepera), little grebe (Tachybaptus ruficollis), kestrel
(Falco tinnunculus), lesser black-backed gull (Larus fuscus), stock dove
(Columba oenas), green woodpecker (Picris viridis), mistle thrush (Turdus
viscivorus), dunnock (Prunella modularis), common whitethroat (Sylvia
communis), willow warbler (Phylloscopus trochilus), bullfinch (Pyrrhula pyrrhula),
and reed bunting (Emberiza schoeniclus).
16.3.47. Local BAP species recorded during surveys of the proposed cooling water
pipeline corridor were skylark, tree pipit (Anthus trivialis), linnet, cuckoo (Cuculus
canorus), reed bunting, spotted flycatcher (Muscicarpa striata), dunnock, bullfinch
(Pyrrhula pyrrhula), starling (Sturnus vulgaris), and song thrush.
Non-Breeding Birds - Proposed Development Site
16.3.48. The following species relevant to the SPA and Ramsar designation were noted
on the Proposed Development Site:
• Lapwing – small numbers (less than 20) were heard on inland area at
night. In inclement weather (snow cover), 67 individuals were recorded
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during the day onsite. Lapwing are listed as a BOCC species since at
least 20% of the European population winters in the UK.
• Dunlin – occasional very low counts on inland area (maximum 14
individuals). The UK population has declined by over 50% in the longer
term (since 1969) and the majority of the wintering population is confined
to only a few UK sites.
• Teal - mostly on the estuary, with single figure numbers on the inland
section of the Proposed Development Site. Listed as at least 20% of the
European population winters in the UK.
• Ringed plover – individuals or pairs of birds recorded on estuary and
inland section of the Proposed Development Site. Listed as at least 20%
of the European population winters in the UK.
• Snipe – up to 35 individuals recorded at night on inland section of the
Proposed Development Site. Snipe is a species of conservation concern
at European population level.
16.3.49. A pair of peregrine falcons was regularly observed resting on pylons within the
Proposed Development Site.
16.3.50. Other species of conservation concern recorded during the surveys on the
Proposed Development Site footprint were:
• Herring gull – on hard standing areas and associated seasonal water
bodies immediately adjacent to the Proposed Development Site, and
also on field along eastern and northern site boundary foraging. Flocks of
up to 111 were recorded. The UK non-breeding population has declined
by over 50% over a period of 25 years.
• Kestrel – a pair was present on inland area of the Proposed
Development Site. This is a species of conservation concern at
European population level.
• Barn owl – two individuals observed, hunting within the Proposed
Development Site. This is a species of conservation concern at
European population level.
• Kingfisher – one individual recorded on the Proposed Development Site
on one occasion. This is a species of conservation concern at European
population level.
Amphibians
16.3.51. Desk study data has indicated records of smooth newt (Lissotriton vulgaris) and
great crested newt (Triturus cristatus) within 1.5km of the centre of the Proposed
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Development Site. Previous surveys undertaken in 2007 and 2010 to inform
proposals for cumulative schemes in the area identified the presence of great
crested newts in three ponds over 500m north of the Proposed Development
Site.
16.3.52. The surveys confirmed presence of a low population of smooth newts and no
evidence of palmate newts or great crested newts on the Proposed Development
Site. Therefore no further action with regards to these species needs to be taken.
16.3.53. GCN surveys of ponds in proximity to the proposed cooling water pipeline
corridor will be undertaken in 2014 and reported in the ES.
Reptiles
16.3.54. A maximum of eight adult grass snakes and two juvenile grass snakes were
recorded on the Proposed Development Site during one survey visit. Reptiles
were found to be using the scrub and grassland habitat to the north of the Site,
and the south facing bank adjacent to the Red Rhine at the southern end of the
Site. Due to the presence of juveniles it was deemed that grass snakes are
breeding in the scrub and grassland mosaic at the northern end of the Site.
Based on survey results, there is considered to be a high (>4 individuals / ha
(HGBI, 1998)) population of grass snake. The Proposed Development Site is
thus considered to be of Medium (County) value for reptiles.
16.3.55. Surveys of suitable reptile habitat in the proposed cooling water pipeline corridor
will be undertaken during 2014 and reported in the final ES.
Badgers
16.3.56. Based on preliminary findings it is likely that badgers exit within the scrub onsite
or in the vicinity of the Site, however further surveys will be undertaken in
2013/14 for badger presence on the Proposed Development Site and the
proposed cooling water pipeline corridor. The results will be presented in the final
ES.
Water Vole
16.3.57. Based on preliminary findings it is likely that water voles occur within the Red
Rhine. Further surveys will be undertaken in 2013/14 for water vole presence on
the Proposed Development Site and proposed cooling water pipeline corridor.
The results will be presented in the final ES.
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Otter
16.3.58. Further surveys will be undertaken in 2013/14 for otter presence on the Proposed
Development Site and the proposed cooling water pipeline corridor, and the
results will be presented in the final ES.
Invertebrates – Terrestrial on the Proposed Development Site
16.3.59. In samples from the Proposed Development Site analysed to date, six species of
conservation interest have been identified, including one Nationally Scarce A and
NERC S41 species Necklace Ground Beetle (Carabus monilis) and four
Nationally Scarce B species: Red-shouldered Longhorn Beetle (Anaglyptus
mysticus), Coal Blackclock beetle (Pterostichus anthracinus), Clay Blackclock
(Pterostichus longicollis), and a wolf spider (Pardosa agrestris). Nationally Scarce
A species are currently known to exist in 30 or fewer ten-kilometre squares.
Nationally Scarce B species are currently known to exist in 31 - 100 ten-kilometre
squares.
16.3.60. Further surveys, including suitable habitat on the proposed cooling water pipeline
corridor will be undertaken in 2014 for terrestrial invertebrate presence onsite,
and the results will be presented in the ES.
Invertebrates – Aquatic
16.3.61. Analysis of aquatic invertebrates sampled in 2013 is ongoing and the data will be
reported in the ES. Further surveys will be undertaken in 2013/14 for aquatic
invertebrate presence onsite, and the results will be presented in the final ES.
Fish
16.3.62. Analysis of the importance of the rhines and ditches to support fish will be
reported in the final ES. Records of eel (Anguilla anguilla) exist for the Red
Rhine.
Resource Evaluation
16.3.63. Table 16-7 summarises the resource evaluation for the habitats and species
discussed above.
Table 16-7: Resource Evaluation
Species Habitat potential Explanation
Designated sites
Very High (International) The Severn Estuary SAC, SPA and Ramsar sites lie, at the closest point, approximately 400m from the nearest point of the Proposed Development Site and 140m from the nearest point of the proposed cooling water pipeline corridor.
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Species Habitat potential Explanation
High (National) The Severn Estuary SSSI is contiguous with the international designations and is designated for supporting nationally important examples of the same habitats and species, along with additional features of national importance.
High (National) Several other SSSIs and one NNR occur within 10km. These are all designated for nationally important features.
Medium (County) There are several LNRs within 10km and SNCIs within 1.5km of the centre of the Proposed Development Site and 1km of the proposed cooling water pipeline corridor.
Habitats Medium (County) value for the Red Rhine and for the habitat mosaic.
Low (Borough) value or Very Low value for the other habitats
There is evidence that the Red Rhine supports water vole, and habitat for eels.
Individually, the remaining habitats on the Proposed Development Site are considered to be of Low (Borough) value or Very Low value
Bats – roosting potential
Very Low Three mature ash trees on the Proposed Development Site have high/moderate potential to support roosting, but activity surveys did not find evidence of presence of roosting bats
Bats – foraging potential
Low (Borough) The linear features and hedgerow on the Proposed Development Site provide foraging and commuting habitat for bats. Six species were recorded foraging within the Proposed Development Site, albeit in low numbers.
Within the proposed cooling water pipeline corridor the rhines and ponds, notably the Salt Rhine ponds along the water pipeline route, attract foraging bat species.
Breeding birds Low (local) – Proposed Development Site
Medium (County) – Proposed Cooling Water Pipeline Corridor
The Proposed Development Site provides limited habitat of value for breeding birds with the exception of a few trees, a few areas of scrub and small lengths of hedgerow. No WCA Schedule 1 species were recorded during surveys and the site supports only low numbers of common species.
Cetti’s warbler, a Schedule 1 species, was recorded on the proposed water pipeline corridor, increasing its perceived value.
Non-breeding birds
Medium (County) – Proposed Development Site
Value to be determined in the ES for the Proposed Cooling Water Pipeline Corridor
The Proposed Development Site was found to support negligible counts of species for which the Severn Estuary SPA and Ramsar sites were designated, either as cited individual species or as part of species listed as part of overall waterbird assemblages. However, the grassland habitats onsite did support populations of wading birds such as snipe and lapwing during the winter period.
The proposed cooling water pipeline corridor runs close to lagoon habitats, and further analysis of desk study data will be undertaken for the ES in order to determine whether the cooling water pipeline route is considered to
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Species Habitat potential Explanation
be of value to non-breeding birds
Amphibians N/A Survey data and receptor assessment will be reported in the final ES.
Reptiles Medium (County) – Proposed Development Site
Negligible – Proposed Cooling Water Pipeline Corridor
Presence of a high population of grass snakes on the Proposed Development Site.
Habitats along the proposed cooling water pipeline corridor were not considered likely to contain significant populations of reptiles, or were considered to be edges of larger habitat parcels
Badger N/A Survey data and receptor assessment will be reported in the final ES.
Water vole N/A Survey data and receptor assessment will be reported in the final ES.
Otter N/A Survey data and receptor assessment will be reported in the final ES.
Terrestrial and aquatic invertebrates
N/A Survey data and receptor assessment will be reported in the final ES.
Fish Low (local) The Red Rhine has records of eel
Flora Negligible Specific botanical surveys were not undertaken, but the Phase 1 habitats survey did not identify and notable species, or non-native or injurious plants.
Future Baseline Conditions
16.3.64. It is anticipated that prior to construction, the ecological baseline of the Proposed
Development Site will change as a result of other developments that do not form
part of the DCO Application.
16.3.65. These other developments, as detailed in Chapter 7: Assessment Methodology
of this PEI Report, include;
• Construction of a new Spine Access Road along the northern perimeter
of the Proposed Development Site, which would connect the roundabout
immediately east of the Proposed Development Site to the A403 to the
west. This will also require a construction right of way within the northern
part of the Site in order to allow access for construction plant to the
southern side of this road for heavy construction plant.
• Construction of a new dry channel for the Red Rhine along the northern
boundary of the Proposed Development Site. No flow diversion will take
place – this will form part of this DCO Application. Again, a construction
right of way will be required within the Proposed Development Site that
will be cleared and levelled.
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• Construction of the SITA Severnside Energy Recovery Centre,
immediately west of the Proposed Development Site. SITA has recently
constructed a haul road through the centre of the Proposed Development
Site to provide access from the roundabout immediately to the east and
its site to the west.
16.3.66. These schemes will have been implemented prior to the start of construction of
the Proposed Development and have the potential to change the baseline
conditions within the Proposed Development Site from those that were assessed
and reported above.
16.3.67. There would be no direct change to any statutory or non-statutory designated
sites as a result of the developments described above. Given statutory and policy
protection of these sites, no measurable changes are anticipated as a result of
other consented developments. The value of these sites is thus assumed to be
the same as the current baseline.
16.3.68. There will be loss or change to some of the existing habitats within the Proposed
Development Site. Grassland and scrub habitat are likely to be cleared from the
northern part of the Proposed Development Site for the spine access road and
diverted Red Rhine corridor. A short stretch of ditch, scrub and grassland habitat
is likely to be cleared from the existing Red Rhine corridor to allow for the haul
road through the centre of the Proposed Development site to the Severnside
Energy Recovery Centre.
16.3.69. The proposed Red Rhine corridor will be isolated from the drainage network,
although it is likely to hold some water from ground and surface water sources.
Based on a review of preliminary engineering drawings by Severnside
Distribution Land Ltd, the diverted rhine appears to have been designed
specifically for the conveyance of surface water rather than ecological mitigation,
with steep bank profiles. Depending on local conditions, reed vegetation may be
expected to develop within the channel, with grassland re-establishing on areas
adjoining the channel.
16.3.70. The network of rhines are expected to reduce in value from Medium (County) to
Low (Borough) as a result of these developments, although this is an estimate
based on relatively little publically available data and the proposed gradients of
the new channel. The remaining areas may remain as Low (Borough) value, or
reduce to Very Low value.
16.3.71. Changes to the extent of habitats on the Proposed Development Site may be
expected to result in some reduction and fragmentation of foraging habitat for
each of the species groups recorded on the Proposed Development Site. The
grassland habitat in the eastern part of the Proposed Development Site will
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remain largely intact, although there will be temporary disturbance due to
construction traffic through the Site. The value for non-breeding birds is therefore
expected to remain as Medium (County). Loss of scrub and semi-improved
habitat in the northern part of the Proposed Development Site may also reduce
the value of the Proposed Development Site for reptiles from Medium (County) to
Low (Borough).
16.3.72. The value of the Proposed Development Site for remaining species receptors is
considered to remain as per the current baseline.
16.3.73. The value of habitats on the proposed cooling water pipeline corridor is unlikely
to change as a result of these other developments described above.
16.3.74. Table 16-8 summarises the value of the ecological receptors on the Proposed
Development Site once the future baseline conditions are taken into account.
Table 16-8: Value of Ecological Receptors under Future Baseline Conditions
Receptor Value within the Proposed Development Site
Value within the Water Pipeline Corridor
Designated sites in the vicinity of the DCO Site
Severn Estuary SAC/SPA/Ramsar
Very High Very High
Severn Estuary and all other SSSIs and Leigh Woods NNR
High High
LNRs and SNCIs/AWTSs
Medium Medium
Habitats Woodland Negligible Negligible
Scrub Low To be reported in ES
Mature trees Low To be reported in ES
Semi-improved grassland
Low To be reported in ES
Tall ruderal Low To be reported in ES
Rhine, ditches and waterbodies
Low To be reported in ES
Hedgerows Low To be reported in ES
Species Bats Low Low
Breeding birds Low Medium
Non-breeding birds Medium Low-Medium
GCN Low To be reported in ES
Reptiles Low Negligible
Badger To be reported in ES To be reported in ES
Water vole To be reported in ES To be reported in ES
Otter To be reported in ES To be reported in ES
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Receptor Value within the Proposed Development Site
Value within the Water Pipeline Corridor
Terrestrial invertebrates
To be reported in ES To be reported in ES
Aquatic invertebrates To be reported in ES To be reported in ES
Fish Low To be reported in ES
Flora Negligible To be reported in ES
16.4. Development Design and Impact Avoidance
16.4.1. A number of impact avoidance measures have been incorporated into the design.
These measures have therefore been taken into account during the assessment
presented in this chapter.
16.4.2. The draft landscaping masterplan is illustrated in Figure 17-15, Volume III of this
PEI Report and has been designed to mitigate a number of environmental effects
or enhance the Site for ecology. In summary it comprises:
• An 8m easement along the southern side of the repositioned Red Rhine
to allow access for maintenance. This easement will be planted with
grassland, ruderal and occasional scrub plants.
• In areas of habitat suitable for reptiles (mosaic of scrub, grassland, tall
ruderals and bare ground), hibernacula will be created. The southern
boundary of the Proposed Development Site will include a mosaic of
habitats planted with tall ruderals, and hedgerow and scrub habitats
interspersed with open grassland and bare ground. There is no limit on
the number or density that could be created, but one approximately every
50-100m would be appropriate.
• Strips of rough, tussocky grassland will be maintained alongside the
hedgerow and rhines in order to provide suitable habitat for hunting barn
owls. The 8m easement along the Red Rhine will have value for foraging
barn owl, and for reptiles and water vole if it is allowed to develop into a
tussocky and long grass strip, rather than being closely mown. The strips
will comprise a grass mix suitable for unimproved grassland habitat,
incorporating species such as false oat grass (Arrhenatherum elatius), red
fescue (Festuca rubra), meadow-grasses (Poa sp.), Yorkshire fog (Holcus
lanatus) and cocksfoot (Dactylis glomerata).
• Up to 0.38ha of surface water features will be incorporated in to the
Proposed Development Site as landscaped attenuation ponds/ditches.
Where practical, these will have shallow sloping margins, allowing access
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and egress for amphibians, reptiles and small mammals. They will be
planted with marginal vegetation focusing on aquatic grasses, such as
creeping bent (Agrostis stolonifera) and the sweetgrasses (Glyceria
species) which provide good invertebrate habitats and provide cover for
breeding water birds, and for grass snake. Submerged and floating
vegetation should be allowed to colonise naturally. Although not required
for water attenuation, the indicative layouts shown in Figure 4-2 and 4-3
in Volume III of this PEI Report include an additional long, thin surface
water feature along the southern boundary of the CCR Site, which can
therefore be designed specifically for ecological benefits rather than flood
attenuation.
• Incorporation of green roofs and brown roofs onto some of the lower
structures will provide suitable habitat for terrestrial invertebrates. The
roofs will, where possible, incorporate logs to provide a habitat for
invertebrates, wetland areas for the establishment of mosses and lichens,
and boulders and stones.
• Any woodland, scrub, mature trees and hedgerow onsite that are lost to
construction or the operational site will be replaced with alternative
provision onsite with planting of native species. Areas of tree and shrub
planting include along the northern boundary of the Proposed
Development, immediately south of the 8m easement along the
repositioned Red Rhine, the area of landscaping between the Generating
Station Site and CCR Site, and additional areas in the west and south of
the Proposed Development Site.
16.4.3. A landscape and biodiversity masterplan will present details of the design,
planting and long term management of the areas described above, and will be
agreed in liaison with the local authorities and Natural England following receipt
of the DCO. A preliminary landscape and biodiversity masterplan is presented in
Figure 17-15, Volume III – Figures of this PEI Report, which will be updated as
part of the final Environmental Statement.
16.4.4. As a precautionary measure, following good practice guidance, any lighting
scheme associated with the Proposed Development will consider bats within the
detailed design. Landscaping associated with the Proposed Development has
the potential to be used by foraging and commuting bats in future and in order to
maximise the potential of the landscaping to enhance the value of the site for
bats, the risk of lighting disturbance to bats should be minimised. Lighting should,
where possible, be directional (i.e. illuminating as little of the surrounding
environment as possible), and low intensity.
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16.5. Potential Effects and Mitigation Measures
16.5.1. This section describes the potential changes associated with the construction,
operation and decommissioning of the Proposed Development, prior to any
mitigation, and identifies any resulting ecological effects.
Construction Phase
16.5.2. The following changes during enabling works and construction of the Proposed
Development Site and proposed cooling water pipeline corridor are considered to
have the potential to affect ecological receptors:
• Loss and fragmentation of habitats through temporary landtake, and
effects on species that utilise these habitats;
• Disturbance to sensitive species through noise, lighting and human
activity from construction activities;
• Pollution of water courses through run-off. Topsoil and excavated/fill
material will be stored in designated areas away from watercourses, as
explained in Chapter 14: Flood Risk, Hydrology and Water Resources.
In order to avoid pollution risks or risk of physical damage to the Red
Rhine and other ditches prior to their diversion, the CEMP will include
measures to avoid pollution events from works carrying risk within 10m of
the rhines. Reptile and water vole proof fencing will be erected along the
rhine system to exclude these species from the Proposed Development
Site during the clearance phase, if later surveys find these species to be
present onsite;
• Changes to the hydrology of the Proposed Development Site and
proposed cooling water pipeline corridor due to diversion of
watercourses, land raising and other construction activities. This could
directly affect any water bodies hydrologically linked to the Proposed
Development Site, or it could create indirect effects by alteration of
habitat quality where such habitat are dependent on water tables;
• Effects on ecological receptors through dust creation and deposition, and
through atmospheric emissions through movement of construction
vehicles to, from, and within the Site. Such effects can be direct in terms
of physical changes to habitats, with direct and also indirect effects on
species that rely on such habitats. Mitigation for dust deposition is dealt
with in Chapter 11: Air Quality; and
• Displacement of protected species through diversion of the existing Red
Rhine watercourse into the new channel, and through works close to
watercourses along the proposed cooling water pipeline corridor. The
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need for this work to be undertaken during a particular time of year will
be identified following further survey work on water vole presence.
16.5.3. The construction of the proposed cooling water pipeline and electrical connection
is not expected to have any significant ecological implications, however in this
PEI report this is only discussed in terms of its potential to affect birds and bats
based on the survey works undertaken to date. Survey data for other protected
species and habitats along the proposed cooling water pipeline corridor will be
collected in spring/summer 2014, to enable a discussion on the potential effects
and their mitigation for the associated development to be presented in the final
ES.
Designated Sites - Temporary Land Take
16.5.4. There will be no landtake from sites designated for wildlife interest, either
statutory or non-statutory, associated with the Proposed Development or
proposed cooling water pipeline.
16.5.5. There is the potential for nearby designated sites such as the Severn Estuary
SPA/SAC/Ramsar/SSSI, and wetland sites such as Hallen’s Marsh SNCI to be
indirectly affected due to the displacement of birds from the Proposed
Development Site due to habitat loss. Although the CCR Site will be reinstated
following the construction phase, it is not expected to be returned to its current
ecological value or support marshy grassland habitat. Its value is therefore
considered likely to decline to Low (local) value.
16.5.6. The magnitude of change, or impact, on displaced birds on the Severn Estuary
SPA/SAC/Ramsar/SSSI is considered to be Low to Medium, and therefore,
based on Table 16-4, the predicted effects are consider to be minor adverse.
Effects on non-statutory sites which are of Medium value are considered to be
negligible.
16.5.7. The diversion of the Red Rhine will not have any effects on designated sites, as
there will be no significant changes in water flows to the estuary and the rhine is
not linked to other designated sites. Therefore there will be a negligible effect on
designated sites through diversion of the Red Rhine.
Designated Sites - Disturbance
16.5.8. Disturbance of species which form a component of the Severn Estuary SPA,
Ramsar, SSSI or other non-statutory SNCIs could potentially occur through
increased lighting, human presence or noise during construction within the
Proposed Development Site.
16.5.9. The nearest designated site, the Severn Estuary lies over 400m to the west of
the Proposed Development Site and there is already construction activity, notably
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from the SITA Severnside Energy Recovery Centre site, between the Proposed
Development Site and the designation. Noise disturbance has been assessed in
Chapter 12: Noise and Vibration. It is considered that the predicted noise levels
from enabling works and construction activities fall below the measured LAeq
levels at the nearest habitat receptor, which is Chittening Warth within the Severn
Estuary SAC, SSSI and Ramsar sites. The significance of this predicted effect is
therefore assessed as negligible.
16.5.10. Higher noise levels are predicted during site clearance with road construction
noise levels predicted to be 60dB prior to mitigation. However, there is no
demolition work and only limited trees within the site which will be cleared and
this work is expected to take place over a very short space of time.
16.5.11. The northern end of the proposed cooling water pipeline corridor will pass within
approximately 140m of the SPA, Ramsar and SSSI. Noise levels during the
construction of the pipeline are predicted to be 56dB, which is slightly higher than
ambient levels, and was considered in the noise assessment to be minor
adverse. Depending on timing and methodology of works there could be potential
for disturbance of bird species. Disturbance is considered to be a Low magnitude
of change, and therefore the effect on the Severn Estuary is expected to be
minor adverse, and temporary in nature.
Designated Sites - Reduced Water Quality – Run-off
16.5.12. Without mitigation, it is possible that construction activities, particularly removal of
topsoil and excavation, could lead to silt and pollutants entering the Red Rhine
on site, which is hydrologically connected to the Severn Estuary. A CEMP will be
implemented for the Proposed Development and associated infrastructure, which
will include procedures for the storage of chemicals, non-road mobile vehicle
movements, and protection of water courses. Even with these measures in place,
there is likely to be some re-suspension of silt when the new Red Rhine diversion
is connected to the existing watercourse, although this should be temporary.
16.5.13. Given the silty environment of the estuary, the small volumes of silt which may be
re-suspended are considered to be imperceptible when compared with the
sediment loads carried by the tides. The magnitude of change resulting from run-
off on designated sites is considered to be negligible and the significance of the
predicted effect minor adverse.
Designated Sites - Groundwater Contamination
16.5.14. The potential for the Proposed Development to affect ecological receptors, in
particular SNCIs designated for rhines and ditches or dependent species,
through alteration of groundwater levels, or through contamination of
groundwater has been considered. Based on Chapter 13: Ground Conditions the
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effect of the development on ground conditions is considered to be negligible. If
contamination is encountered during construction appropriate remediation
measures will be implemented.
16.5.15. The magnitude of change resulting from ground water contamination on
designated sites is therefore considered to be negligible.
Designated Sites - Air Quality
16.5.16. There are no statutory or non-statutory designated sites within 200m of the main
works site (the distance over which Department for Transport guidance
recommends assessment on ecological receptors should apply for road traffic
emissions) and therefore no likely effects of gaseous emissions from construction
plant and equipment onsite are expected.
16.5.17. Elevated levels of construction traffic accessing the Site could theoretically
contribute to reduced air quality on sites within 200m of main access routes
(primarily the A403). Habitats such as saltmarsh are potentially vulnerable to
reduced air pollution and the construction traffic emissions associated with the
enabling works will lead to an increase in annual mean NOX concentrations at
locations within 100m of the Severn Estuary designated sites. The increase will
be greatest at locations immediately adjacent to the A403, where annual mean
concentrations are already in excess of the national air quality objective for that
pollutant, and also the critical load for coastal saltmarsh. The Severn estuary
designated sites are located 25m from the A403 at their closest point. At
distances of 30-35m from the A403, NOX levels drop below the critical load for
coastal saltmarsh. The main reason for the exceedance is the high background
concentrations. It is considered that construction vehicles would only contribute
a negligible air quality effect on this receptor, as discussed in Chapter 11: Air
Quality.
16.5.18. Dust effects would be theoretically possible on the Severn Estuary designated
sites, but these are situated in the opposite direction to the prevailing wind and
400m from the Proposed Development Site. Given the mitigation measures
proposed in Chapter 11: Air Quality for controlling dust emissions, the prevailing
wind direction and the level of dispersion that occurs over a distance of 400m,
the effect of dust is expected to be negligible.
Habitats - Temporary Land Take
16.5.19. Temporary land take will lead to the loss of habitat onsite. These habitats
comprise primarily poor semi-improved grassland and tall ruderal habitat with
small amounts of scrub, and ditch habitat. Following the construction stage, the
habitats within the CCR Site would be restored to semi-improved grassland,
which would re-establish in the short term (less than 5 years).
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16.5.20. The existing Red Rhine corridor would be infilled, or used as a shallow swale
water feature along the south of the CCR Site (see indicative layouts in Figures
4-2 and 4-3, Volume III of this PEI Report.
16.5.21. The impact of temporary land take is considered to be Medium, since although it
will affect ‘greater than 20%’ of the Proposed Development Site, it will be partially
reversible in the CCR Site and the areas reserved for below ground utilities,
services and landscaping. Effects on habitats are therefore considered to be
minor adverse, given their Low (Borough) value under the future baseline.
Habitats - Reduced Water Quality due to Run-off and Silt Re-suspension
16.5.22. The diversion of the water flow from the existing Red Rhine into the new channel
is likely to result in some re-suspension of silt as the new channel is flooded, with
the potential for smothering effects on downstream habitats. However, the
volumes of re-suspended silt are likely to be small, and will only occur temporarily
and downstream habitats are likely to comprise a significant silt component. The
magnitude of the change is considered to be Low and given the Low (Borough)
value of the habitats effects are considered to be negligible.
Species
Bats (Roosting and foraging) – Temporary Landtake
16.5.23. The temporary loss of scrub and semi-improved grassland onsite will reduce the
value of the Proposed Development Site for foraging bats. New habitats such as
tree screens and the newly created Red Rhine corridor will provide replacement
linear habitat, and the water attenuation areas will provide some replacement
foraging habitat, although the overall reduction in the area of grassland habitat
will reduce the bat foraging opportunities. Nevertheless, the impact is considered
to be Low and, therefore the overall effect is considered to be negligible.
Bats (Roosting and foraging) - Disturbance
16.5.24. Lighting and night time construction activities have the potential to disrupt flight
lines and foraging routes through the Site. With the loss of the existing Red
Rhine corridor foraging routes within the Proposed Development Site are likely to
be restricted primarily to the boundaries of the Site. Temporary lighting will be
focused on the main works areas at the western end of the Proposed
Development Site, although there is likely to be some spillage into the adjacent
habitat which may be used by foraging bats. Although lighting is known in certain
circumstances to delay bats emerging from a roost, there are no known roost
sites, or habitats suitable to support roosting bats close to the Proposed
Development Site. Of the six species recorded foraging within the Proposed
Development Site, five (common and soprano pipistrelle, nocule, Leislier’s and
serotine) are fast flying species which may be favoured by lighting due to
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populations of night flying insects that it supports. One species, Brandt’s may be
disrupted from foraging close to lighting. The impact of lighting is considered to
be Low.
16.5.25. The impact of noise and lighting is considered to be Low, and the overall effect
on bats to be negligible.
Bats (Roosting and foraging) – Reduced Water Quality due to Run-off
16.5.26. Reduced water quality within the newly created Red Rhine corridor has the
potential for impacts on invertebrate populations which bats depend on as a
foraging resource. However, any impacts on water quality are considered to be
temporary following the diversion of the watercourse from the existing channel.
The successful establishment of marginal and aquatic vegetation within the
channel is considered to be most important factor in determining invertebrate
populations. Effects of reduced water quality on bats are thus considered to be
negligible.
Breeding Birds – Temporary Landtake
16.5.27. Temporary landtake will result in the loss of scrub and grassland habitats of value
for breeding birds in the eastern part of the Proposed Development Site. Four
red list species of conservation concern were recorded on the Site, including two,
skylark and lapwing, which are ground nesting and require extensive areas of
grassland habitat. The remaining two red list species, song thrush and linnet
require dense scrub. This portion of the Site will be reinstated to grassland.
Under the future baseline, the Site is considered to be of Low (Borough) value for
breeding birds. Given the Medium impact of temporary landtake, effects on
breeding birds are considered to be minor adverse.
Breeding Birds - Disturbance
16.5.28. Light, noise and human activity during construction could lead to disturbance to
nesting and avoidance of habitats surrounding the Site by breeding bird species.
The highest noise levels are predicted to occur during the site clearance stage,
although with mitigation, noise levels associated with site activities 400m from the
boundary of the Site at Chittening Warth on the Severn Estuary are predicted to
be no more than 10dB.
16.5.29. No noise data is available for habitats adjacent to the Site, but levels are very
likely to be higher than this, and may cause some displacement of birds and
discouragement of nesting activity in habitats immediately adjacent to the Site.
Given the already high levels of industrial activity in the area, and the temporary
nature of operations such as piling, the magnitude of change is considered likely
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to be ‘Low’, though this may require re-evaluation as construction plans are
developed.
Non-Breeding birds – Temporary Landtake
16.5.30. The Proposed Development Site was found to be of value to wading birds, in
particular snipe, which is a species specifically listed in the SSSI citation for the
Severn Estuary. Under future baseline conditions the value is likely to be Medium
(County), as noted above. The temporary loss of extensive areas of grassland
habitat is considered to be a ‘Low’ magnitude of change. Whilst there is some
equivalent habitat available to the south of the Proposed Development Site, as
well as marshland that forms part of the SSSI itself, the temporary loss of this
habitat from the Proposed Development Site is considered to be a minor
adverse effect.
16.5.31. When taking this into account with the effects of permanent landtake in the
western part of the Proposed Development Site for the Proposed Development,
and considering that the CCR Site is not expected to be returned to its current
value for marshland habitat, the effects of temporary landtake on non-breeding
birds, specifically snipe, is considered to be moderate adverse, and therefore
significant without mitigation.
16.5.32. It is worth noting that this is based on the value of the CCR Site being ‘Medium’.
However, given the extent of the work onsite currently by third parties associated
with the installation of the new Spine Access Road, Red Rhine diversion, and
creation of a haul road through the Proposed Development Site, it is considered
unlikely that the CCR Site is currently used by snipe or any other birds. It is not
known whether these developers will reinstate the Proposed Development Site to
its pre-disturbed environment and whether the potential effect on non-breeding
can therefore be classified as minor adverse, or if the current site conditions will
be reinstated prior to enabling works for the Proposed Development.
16.5.33. Overarching NPS for Energy (EN-1) advises that DCO requirements and/or
planning obligations should be used not only to mitigate any significant harm
arising from a proposed development on a SSSI but also where possible, to
conserve and enhance the SSSI’s biodiversity interest. The Applicant will
therefore explore opportunities with SGC, BCC and NE to contribute to the
management of land off-site for the benefit of bird interests in the Severnside
area to provide long-term habitat creation and management for species such as
snipe. Further details will be reported in the DCO Application.
Non-breeding Birds - Disturbance
16.5.34. Construction activities have the potential to displace non breeding species such
as snipe and lapwing from the Proposed Development Site. Although some work
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areas will be surrounded by noise barriers which will reduce levels of
disturbance, activity on haulage routes and laydown areas in the eastern part of
the site will be unscreened. When considered in combination with the loss of
habitat due to temporary landtake the Proposed Development Site, the suitability
of the site to support non-breeding birds will be considerably reduced during
construction. The impact of disturbance combined with landtake is considered to
be High and the overall effect moderate adverse, and therefore significant
without mitigation. This is based on the site conditions pre-December 2013
however, which no longer exists onsite. The Applicant is willing however to
explore opportunities to contribute to the management of land off-site for the
benefit of bird interests in the Severnside area to reduce this effect to minor
adverse significance.
Reptiles – Temporary Landtake
16.5.35. The site currently supports a medium population of reptiles, which appears to be
focused primarily around the scrub and grassland habitats associated with the
Red Rhine corridor and towards the northern edge of the Site. All of this habitat
will be lost to temporary landtake, although grassland habitat will be established
in the landscaped areas of the scheme, and there will be scrub within the
proposed swale corridor to the south of the CCR Site. However, these habitats
are much smaller in scale than under the current baseline, and will take time to
establish sufficiently to support a viable reptile population. Impacts of landtake
are considered to be Medium, and the effects are considered to be minor
adverse.
Prior to commencement of construction, reptile proof fencing will be erected
along the rhine system to exclude reptiles (and water voles) from the Site during
the clearance phase. A high density of traps will be placed within the Site where
suitable for reptiles, and they will be checked daily for a total of 60 suitable days
prior to the Site being cleared. This will be undertaken during May and June
(when grass snake numbers were highest) and where possible only on fair
weather days where the temperature is between 10 - 20 degrees Celsius.
16.5.36. A precautionary approach to reptile vegetation clearance will be adopted once
the trapping stage has been completed. This will involve clearance in a phased
and controlled manner using hand-held machinery and under ecological
supervision. Ecologists will undertake a ‘finger-tip’ search for reptiles within the
area to be cleared. This will encourage reptiles to vacate these areas of their own
volition. Soil, stones, roots, mammal holes etc. will be checked for reptiles by
hand investigation. If any reptiles are encountered they will be moved to the
translocation area of the retained habitat the other side of the reptile fencing.
Hand strimmers or brush cutters will follow the ecologist’s lead and cut vegetation
to a height of 100mm; the cut material will be hand raked to the sides of the area.
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All strimming will be phased, working outwards towards the periphery of the
development footprint to areas which are to be retained. If any reptiles are
encountered, works will need to cease and an ecologist will move the reptiles to a
safe area before recommencing works. All clearance work will be undertaken
during April to September in order to coincide with reptiles' active seasonal period
and where possible will be undertaken within a temperature range of 16 – 24
degrees Celsius in suitable weather conditions.
Reptiles - Disturbance
16.5.37. Construction activity, particularly during the site clearance stage, has the
potential to disturb reptiles within remaining areas of grassland and scrub.
However, given that the receptors are relatively insensitive to noise and light
impacts, the major consideration would be vibration through processes such as
piling, and heavy vehicle movements. The impact is considered to be Low, since
measures to avoid killing and injuring of reptiles through temporary landtake
discussed above would ensure that reptiles were not present within the areas
likely to be affected by vibration effects on Site, though areas of immediately
surrounding habitat could also be subject to disturbance. The effect is therefore
considered to be negligible.
Flora – Temporary Landtake
16.5.38. The Proposed Development Site currently supports a range of common plant
species, with no notable species of flora. Temporary landtake will result in a loss
of plant species, however grassland habitat will be established in the landscaped
areas of the scheme, and there will be scrub within the proposed swale corridor
to the south of the CCR Site. A number of enhancement measures have been
outlined above that are expected to ensure an equivalent range of species is re-
established on the Proposed Development site. The magnitude of change is
therefore considered to be Very Low/Negligible, resulting in a negligible effect.
Flora – Reduced Water Quality
16.5.39. Without mitigation, it is possible that construction activities, particularly removal of
topsoil and excavation, could lead to silt and pollutants entering the Red Rhine
on site, which contains aquatic and marginal plant species. A CEMP will be
implemented for the Proposed Development and associated infrastructure, which
will include storage of chemicals, plant movements, and protection of water
courses, as discussed in Chapter 13: Ground Conditions and Chapter 14: Flood
Risk, Hydrology and Water Resources of this PEI Report. Given these
measures, the magnitude of change resulting from run-off on flora is considered
to be negligible and effects are negligible.
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Other Species
16.5.40. Effects on amphibians, water voles, badgers, aquatic and terrestrial invertebrates
will be assessed following completion of baseline surveys and reported in full in
the ES.
Operational Phase
16.5.41. The following changes associated with operation of the completed scheme have
the potential to affect ecological receptors:
• Loss of habitats through permanent landtake, and effects on species that
utilise these habitats. Such changes could be direct due to occupation of
land by the operational site, or indirect by reducing or causing
fragmentation of available habitat in the wider area;
• Disturbance to sensitive species through noise and visual impacts of
operational activities;
• Pollution of water bodies through emissions from the operational power
station;
• Air quality reductions through emissions from the operational generating
station. Such effects can be direct, in terms of physical changes to
habitats, with direct and also indirect effects on species that rely on such
habitats;
• Effects on ecological receptors from atmospheric emissions from
vehicles moving to and from the site. Such effects can be direct in terms
of physical changes to habitats, with direct and also indirect effects on
species that rely on such habitats.
16.5.42. The operation of the proposed cooling water pipeline and electrical connection is
not expected to have any ecological implications, and hence is not discussed
further.
Designated Sites - Permanent Land Take
16.5.43. There will be approximately 8.5ha of permanent land take associated with the
Proposed Development within the Generating Station Site, primarily focused in
the western part of the Site where the Generating Station will be located. None of
this would take place on sites designated for wildlife interest, either statutory or
non-statutory.
16.5.44. There would be potential for the loss of habitat to indirectly affect designated
sites through displacement of birds from supporting habitat that exists onsite.
Although the Proposed Development Site has value for species that form part of
an assemblage of waterfowl for which the Severn Estuary SPA and Ramsar sites
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are designated, cumulative numbers of relevant species recorded onsite during
surveys in 2012 and 2013 did not exceed greater than 1% of the total
assemblage for which the designated sites qualify.
16.5.45. Numbers of snipe recorded onsite however were notable in the context of the
population of the Severn Estuary SSSI, for which the species is listed in the
citation. In combination with temporary landtake and disturbance, permanent loss
of habitat on the Proposed Development Site is likely to cause the displacement
of snipe onto other areas. The effect of this displacement is difficult to predict,
but is likely to cause either a Low or Medium change depending on the carrying
capacity of the receiving sites. Indirect effects on the Severn Estuary SSSI are
thus considered to be minor adverse.
Designated Sites - Disturbance
16.5.46. Disturbance of species which form a component of the Severn Estuary SPA,
Ramsar, SSSI or other non-statutory SNCIs could potentially occur through
increased lighting, visual presence or noise surrounding the operational site. The
nearest designated sites lie over 400m to the west and there is already
intervening infrastructure and visual, noise and light exposure of receptors. The
magnitude of change through disturbance on designated sites is considered to be
Very Low/Negligible, resulting in an effect of negligible significance.
Designated Sites - Reduced Water Quality
16.5.47. The Proposed Development will not require abstraction of water from the Severn
Estuary and there will be no direct discharge of water into the Severn Estuary. All
water necessary for cooling of the power station will be taken from and returned
to the Bristol WWTW. The magnitude of change is therefore considered to be
Very Low/Negligible, resulting in an effect of negligible significance.
Designated Sites - Air Quality
16.5.48. As part of the HRA, Environment Agency guidance (Ref. 16-7) suggests that
SACs, SPAs, and Ramsar sites up to 10km distant should be assessed. The
Proposed Development, when operational, will emit known pollutants to air, via
stacks. These will include the combustion products nitrogen oxides, carbon
monoxide and (for the short periods when distillate firing may be used) particulate
matter and sulphur dioxide. The ecological receptors assessed are all predicted
to result in NOX concentrations below the threshold for insignificance for daily and
annual mean critical levels, as shown in Chapter 11: Air Quality. Therefore it is
concluded that there will be a negligible effect of air quality on the designated
sites, leading to a minor adverse effect on the Severn Estuary SAC/SPA/Ramsar,
and SSSIs, and a negligible effect on LNRs and non-statutory sites.
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Habitats on the Proposed Development Site - Permanent Land Take
16.5.49. Permanent land take will lead to the loss of 8.5ha of habitats, primarily semi-
improved grassland and tall ruderal habitat with small amounts of scrub, mature
trees and ditches potentially affected also. However, the development will include
6.4ha of landscaping, which will seek to replicate the habitats to be lost, and add
new features such as ponds, a swale and species rich grassland. Taking into
account the landscaping, the magnitude of change to habitats is considered to be
High, except on water courses as the Red Rhine diversion means that this
feature will still be present on site. Given the Low (Borough) value of the habitats
present the predicted effects are considered to be minor adverse.
Habitats on the Proposed Development Site – Hydrology and Groundwater
Quality
16.5.50. Land raising associated with the western part of the Proposed Development Site
have the potential for effects on the remaining drainage network both on and
adjacent to the Site. Run off from sealed surfaces will be attenuated through the
pond feature in the central portion of the Site. An assessment of effects on
surface and groundwater bodies within and adjacent to the Site is presented in
Chapter 13: Ground Conditions. With appropriate mitigation, the predicted effects
are considered to be negligible.
Habitats on the Proposed Development Site – Air Quality
16.5.51. As with offsite habitats, the magnitude of change associated with air quality
onsite is considered to be Low, and the effect is therefore negligible.
Bats (Roosting and foraging) – Landtake
16.5.52. The group of three mature trees considered to have potential for bats will be lost
due to permanent landtake. However, there will be tree planting within the
landscaping areas for the Site, which will increase the availability of bat roosts in
the long term. Bat boxes will also be installed on planted trees to increase the
availability of roosting habitats. The impact on roosting bats will be Low and
beneficial. The permanent loss of the existing Red Rhine corridor, with the
established areas of scrub and semi-improved grassland associated with it, will
reduce the value of the site for foraging bats. Replacement habitats will be
incorporated into the landscaping for the scheme. The overall impact is
considered to be Low and due to the Low (Borough) value of the receptor the
overall effect will be negligible.
Bats (Roosting and Foraging) - Disturbance
16.5.53. There is potential for disturbance to bats during the operation of the Site due to
lighting and noise. There will be permanent lighting within the Site which has the
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potential to disrupt bat foraging routes and behaviour. Fast flying species, such
as common and soprano pipistrelle, noctule and serotine, which feed on insect
prey attracted to lighting may become more numerous. Slower flying species
such as Brandt’s bat may be discouraged from foraging nearer lit areas. Overall
the effects of lighting are considered to be negligible given the existing industrial
setting of the area including the adjacent Seabank 1 & 2.
16.5.54. No noise assessment is available for receptors within the Proposed Development
Site boundary, although an assessment has been made at Chittening Wharf,
400m to the west on the Severn Estuary. Night time noise levels at this receptor
are expected to increase by between 1 and 2dB depending on whether the single
shaft or multi-shaft option is selected. Effects on bats are therefore considered to
be negligible.
Breeding Birds - Landtake
16.5.55. Permanent landtake will lead to the loss of nesting habitat for scrub and ground
nesting species such as song thrush, linnet, skylark and lapwing. There is
available habitat for these species in the wider landscape. Therefore the impact
is considered to be Low, and the effect on breeding birds is negligible.
The turbine and HRSG building will be fitted with nesting platforms and boxes
suitable for peregrine falcon as they are known to utilise the Site currently for
perching and hunting, assuming they are still in the area at the start of
construction (currently forecast to be 2017). Peregrine nest boxes will generally
be located above 25-30m height above ground and north- or east-facing.
Non-Breeding Birds - Landtake
16.5.56. The habitat is also of value to non-breeding species, in particular snipe, which is
a species specifically listed in the SSSI citation. Although grassland and scrub
habitats will be incorporated into the layout of the Site, these are not considered
to offer suitable habitats for snipe, which require large areas of seasonally
flooded grassland which are free of disturbance.
16.5.57. The Severnside & Avonmouth Wetland Habitat Project (Ref. 16-7) identified that
the ‘loss’ of wetland habitats within the footprint of the 1957/58 Planning Consent
Area would be expected to result in a reduction in foraging (and potentially
roosting) opportunities for snipe, possibly leading to associated displacement
effects. Dependent on extent of development in the area, it was suggested that
further losses of habitat arising as a result of the 1957/58 Severnside Consent
could lead to associated reductions in the overall carrying capacity of these
areas, which could result in the displacement of common snipe from the
Severnside area.
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16.5.58. The CCR Site will be reinstated following completion of construction activities,
although this is likely to support dry neutral grassland which may be of value to
ground nesting species such as skylark. It is not expected that it would be
reinstated to the existing marshy grassland, which was of value to snipe. The
proposed management of the CCR Site will be described in the landscape and
biodiversity masterplan, which will be produced as part of the final ES however it
is clear in the national guidance that the CCR Site would not be allowed to
enhance through neglect and some level of active management will be required..
16.5.59. The effects of temporary and permanent landtake on non-breeding birds,
specifically snipe, is considered to be moderate adverse, and therefore
significant without mitigation. However this is based on the site conditions pre-
December 2013 however, which no longer exists onsite; based on the current
baseline the effect is minor adverse, however it is not known whether the third
party developers currently working onsite will choose to reinstate the site to its
current value. Regardless, the Applicant is willing explore opportunities to
contribute to the management of land off-site for the benefit of bird interests in
the Severnside area to reduce this effect to minor adverse significance.
Breeding and Non-breeding birds - Disturbance
16.5.60. The visual presence of the Proposed Development, and light and noise
generation could lead to avoidance of habitats surrounding the site by bird
species. However, given the levels of industrial activity in the immediately
surrounding area, and the availability of suitable habitat for species in the wider
landscape, the magnitude of change in species abundance or diversity is
considered to be ‘Low and effects are considered to be negligible for breeding
species and minor adverse for non-breeding species.
Reptiles – Landtake
16.5.61. The Proposed Development Site currently supports a medium population of
reptiles. Approximately 8.5ha of habitats, primarily semi-improved grassland and
tall ruderal habitat with small amounts of scrub would be lost to permanent
landtake and these are habitats of value to reptile species known to be present
on the Proposed Development Site. Impacts of permanent landtake are
considered to be Medium, and the effects are therefore predicted to be minor
adverse.
Reptiles - Disturbance
16.5.62. Operational site activity is not considered to have potential to disturb reptiles
within areas of grassland and scrub. The impact is considered to be Very
Low/Negligible, leading to a negligible effect.
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Flora – Landtake
16.5.63. The Proposed Development Site currently supports a low diversity of flora
species. Approximately 8.5ha of habitats, primarily semi-improved grassland and
tall ruderal habitat with small amounts of scrub would be lost to permanent
landtake within the Generating Station Site and therefore some common species
would be reduced in population size or lost. However, green and brown roofs as
part of enhancement of the Proposed Development Site will offer a more diverse
range of plant species on areas of permanent landtake. Impacts of landtake are
therefore considered to be negligible overall, and the predicted effect is
negligible.
Other Species
16.5.64. The effects on amphibians, invertebrates and mammals will be assessed once
baseline data sets are completed and reported in full in the ES.
Decommissioning Phase
16.5.65. The Proposed Development will have a minimum 30 year design life, with an
operational life that may be extended beyond that subject to its performance and
asset condition. The decommissioning process is expected to include removal of
structures on Site, although the cooling water pipeline would likely be left in situ
to avoid disturbance. There would be potential changes on ecological receptors
through disturbance, air quality and water quality during this process. The
baseline conditions cannot be accurately predicted at his stage, and the methods
of decommissioning are also difficult to predict. Given that the site would be
changing from an industrial, developed site, either to altered use, or
reinstatement to natural environment, it is considered likely that effects would be
neutral or beneficial to ecological receptors. The decommissioning phase is not
considered further in this report, given the uncertainties surrounding the
timescale of assessment and the likely associated effects.
16.6. Residual Effects
16.6.1. Table 16-9 provides a summary of the predicted residual effects following
mitigation.
Table 16-9: Summary of Residual Effects
Receptor Construction Phase Operational Phase
Designated sites
Severn Estuary SAC/SPA/Ramsar
Minor adverse Minor adverse
Other designated sites Negligible Negligible
Habitats onsite
Landtake Minor adverse Minor adverse
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Receptor Construction Phase Operational Phase
Species Bats Negligible Negligible
Breeding birds Minor adverse Negligible
Non-breeding birds Moderate adverse Minor adverse
Reptiles Minor adverse Minor adverse
Flora Negligible Negligible
Badger To be determined in the final ES
To be determined in the final ES
Water vole To be determined in the final ES
To be determined in the final ES
Otter To be determined in the final ES
To be determined in the final ES
Terrestrial invertebrates
To be determined in the final ES
To be determined in the final ES
Aquatic invertebrates To be determined in the final ES
To be determined in the final ES
Fish To be determined in the final ES
To be determined in the final ES
GCN To be determined in the final ES
To be determined in the final ES
16.6.2. The construction phase is anticipated to lead to a number of minor adverse
effects, as well as a moderate adverse effect on non-breeding birds, as
summarised below.
16.6.3. The northern end of the proposed cooling water pipeline corridor will pass within
approximately 140m of the SPA, Ramsar and SSSI, and noise levels during the
construction of the pipeline is expected to lead to a minor adverse effect on this
designated habitat, although the pipeline installation will be relatively rapid and
the disturbance therefore temporary in nature.
16.6.4. Temporary landtake will result in the loss of scrub and grassland habitats of value
for breeding and non-breeding birds in the eastern part of the Proposed
Development Site. The predicted effects on birds using this land are considered
to be moderate adverse (assuming the pre-December 2013 site conditions are
reinstated prior to enabling works for the Proposed Development), but with the
potential to reduce to minor adverse following offsite mitigation.
16.6.5. Construction activities have the potential to displace non breeding species such
as snipe and lapwing from the Proposed Development Site. When considered in
combination with the loss of habitat due to temporary landtake at the Proposed
Development Site, the suitability of the Site to support non-breeding birds will be
considerably reduced during construction. The impact of disturbance combined
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with landtake is considered to be High and the overall effect moderate adverse,
reducing to minor adverse following offsite mitigation.
16.6.6. This conclusion is based on the baseline conditions assessed in this PEI Report.
However, given the extent of earth moving work and construction currently taking
place onsite to enable SITA’s Severnside Energy Recovery Centre, as well as
the Spine Access Road and realigned Red Rhine (see Chapter 7: Assessment
Methodology for a full description), it is expected that the revised baseline may
affect the significance of these effects associated with the Proposed
Development, reducing this to minor adverse significance. The revised baseline
will be assessed within the final ES.
16.6.7. The operational phase is not anticipated to lead to any moderate or major effects,
although a number of minor adverse effects have been identified. This includes
minor indirect effects on the Severn Estuary due to the potential disturbance to
and loss of habitat onsite for snipe, which may cause displacement of this
species onto other areas; this has resulted in a minor adverse effect being
assigned to both non-breeding birds and indirect effects on the Severn Estuary
SAC/SPA/Ramsar/SSSI habitat. The direct loss of habitats onsite, primarily semi-
improved grassland and tall ruderal habitat with small amounts of scrub, mature
trees and ditches, is also considered minor adverse following the reinstatement
of some areas and proposed landscaping strategy during operation.The visual
presence, light and noise generation of the operational Proposed Development
could lead to avoidance of habitats surrounding the site by bird species.
However, given the levels of industrial activity in the immediately surrounding
area, and the availability of suitable habitat for species in the wider landscape,
the operational effects once the CCR Site has been reinstated to grassland are
considered to be, at worst, minor adverse for non-breeding species.
16.6.8. The Site currently supports a medium population of reptiles, which appears to be
focused primarily around the scrub and grassland habitats associated with the
Red Rhine corridor and towards the northern edge of the Site. All of this habitat
will be lost to temporary landtake, although grassland habitat will be established
in the landscaped areas of the scheme, and there will be scrub within the
proposed swale corridor to the south of the CCR Site. However, these habitats
are much smaller in scale than under the current baseline, and will take time to
establish sufficiently to support a viable reptile population. This is anticipated to
lead to a minor adverse effect on reptiles.
16.7. Cumulative Effects
16.7.1. This section considers the cumulative effects of the Proposed Development
along with other consented schemes within the vicinity, as listed in Chapter 7:
Assessment Methodology.
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16.7.2. The mechanisms by which the Proposed Development and associated
infrastructure could potentially contribute to cumulative effects with these other
schemes are:
• Land take - loss of further habitat in the local area could, cumulatively
lead to pressure on supporting habitats for designated sites, and on
habitats of value for species identified during ecological survey works
at the Proposed Development Site.
• Disturbance – other consented works in the local area could lead to
further displacement of species that could already suffer disturbance
as a result of the Proposed Development Site.
• Air quality – other developments in the local area could contribute to
reduced air quality, in particular on roads that run within 200m of
designated sites, through increased emissions of pollutants from
vehicles.
• Water quality – other developments that would lead to discharges to
water courses that flow into the Severn Estuary could contribute to
cumulative loss of water quality.
16.7.3. In particular in the Severnside area, planning permission was granted for
industrial, office, warehouse and other ancillary uses on 1030ha of land at
Severnside in 1957 (hereafter referred to as the ‘1957/58 Severnside Planning
Consent’), which remains extant for future development. The review of the
1957/58 Severnside Consent has identified that up to approximately 456,900m2
of grazing pasture could be ‘lost’ under the future development footprint, based
upon a worst-case scenario.
16.7.4. The ecological assessments for the cumulative schemes have been reviewed to
identify the potential for significant cumulative effects. In particular, the following
was noted for the three cumulative schemes that identified as having significant
effects or requiring extensive mitigation or compensation:
• The ES for the ‘Deep Sea Container Terminal’ identified potential
moderate adverse effects for some species. However there is not likely
to be cumulative effects with the Proposed Development Site as the
habitat usage of the two sites by birds is different and any
displacement or disturbance of birds feeding on the foreshore would
lead to birds attempting to feed elsewhere on the foreshore and not
inland.
• The ES for the New Earth Solutions gasification plant identified the
need for a financial contribution to the Severnside and Avonmouth
Wetland Habitat project to mitigate adverse effects on protected
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May 2014 Page 16-50
species and loss of habitat. This project is currently under construction
however and therefore the loss of this land already forms part of the
baseline rather than having the potential to lead to cumulative effects.
• The 1957/58 Consent included a requirement for setting aside 38ha of
land for ecology enhancements and the creation of green corridors.
The delivery of the ‘1957/58 development’ is not complete and hence
the ecological reserve has not yet been delivered, but it offers the
potential to reduce cumulative effects associated with landtake in the
wider area.
16.7.5. The gradual increasing re-industrialisation of Severnside, through the Proposed
Development and cumulative schemes identified in Chapter 7: Assessment
Methodology, has the potential to lead to a significant effect on bird species
associated with the Severn Estuary SAC/ Ramsar site, due to loss of wetland
habitat and disturbance. As identified above however, the Proposed
Development is only expected to have a negligible effect on this designated
habitat site, and the species for which it is designated have not been found to use
the Proposed Development Site. A moderate adverse effect has been identified
from the Proposed Development for non-breeding bird species, for which the
Severn Estuary SSSI has been designated. However this is based on the site
conditions pre-December 2013, which no longer exists onsite; the effect is only
considered minor adverse if the third party developers working onsite currently
choose not to reinstate the site to current conditions. The Applicant is wiling to
explore opportunities to contribute to the management of land off-site for the
benefit of bird interests in the Severnside area however to ensure this effect will
be of minor adverse significance.
16.7.6. It is not anticipated that there is the potential for cumulative effects related to any
other species or habitats. A minor adverse effect has been identified for reptiles,
but again, it is expected that the revised baseline for the final ES may affect the
significance of this effects, possibly reducing it to negligible significance. The
other effects associated with the Proposed Development are considered to be
negligible (or have not yet been determined) and are therefore unlikely to have
the potential to cause any cumulative effects.
16.8. Impacts and Effects yet to be Determined
16.8.1. It is likely that the baseline conditions will change between the preparation of this
PEI Report and the final ES. The Proposed Development Site is currently subject
to excavation, top soil stripping, and levelling in certain areas in order for third
parties to deliver the Spine Access Road and new channel for the Red Rhine,
which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7:
Assessment Methodology. A haul road is also being constructed through the
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middle of the Proposed Development Site to enable access by third party from
the roundabout to the east of the Site to the Severnside Energy Recovery Centre
to the west. These works onsite are being undertaken by other developers, under
extant planning permissions and are separate to the Proposed Development.
16.8.2. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changed
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
16.8.3. At this stage, baseline data is also still being collected and therefore further
effects requiring mitigation may be identified following publication of this PEI
Report. These will be addressed as part of the final ES to be prepared for
submission in support of the DCO application. Enhancement measures that are
not essential for mitigation, but that would be recommended to accompany the
development on the Proposed Development Site have been described above.
16.8.4. The information in Table 16-10 below indicates the surveys that remain to be
completed in order to finalise the baseline for ecological receptors. Information
obtained from these surveys will be used to update this chapter for the final ES.
Table 16-10: Proposed Survey Requirements for the Final ES
Receptor Survey Required for Proposed Development Site
Survey Required for Other DCO Land
Habitats No further survey work is planned
A rapid habitat survey has been carried out along the proposed cooling water pipeline corridor to identify which protected species surveys are required; the Extended Phase 1 habitat survey for the pipeline corridor will be presented in the final ES.
Breeding birds
No further survey work is planned
Some of the proposed water cooling pipeline corridor also still requires completion of the breeding bird surveys. The results will determine whether avoidance or mitigation measures are required along the cooling water pipeline corridor in order prevent significant effects on bird species.
Amphibians No further survey work is planned
Amphibian surveys commenced in May 2013 and will be completed in April 2014. The results of pond surveys on the proposed water cooling pipeline corridor will determine whether there is a requirement to avoid water bodies in the vicinity of the pipeline route, or whether the works are likely to affect great crested newt terrestrial habitat within 500m of occupied ponds. Any works likely to affect GCNs may require a licence to be sought from Natural England in order to mitigate for effects on the
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Receptor Survey Required for Proposed Development Site
Survey Required for Other DCO Land
European Protected Species.
Reptiles No further survey work is planned
Surveys of suitable reptile habitat on the proposed water cooling pipeline corridor will be undertaken during 2014 and reported in the final ES. The result will inform any mitigation required along the pipeline route, for example, trapping or exclusion of reptile populations.
Badgers Surveys will be undertaken for badger presence. The results will inform any mitigation required, for example, closure of active setts under Protected Species licence, creation of artificial setts, and installation of structures to ensure badgers are not trapped by any construction or operational features.
Water Vole Surveys will be undertaken for water vole presence. The presence of water vole along rhines may require mitigation in order to avoid adverse effects on the population. Works may need to avoid encroaching along the edges of the Red Rhine during construction for example. Prior to connection of the diverted Red Rhine channel, the new channel would need to be assessed as being suitable for water voles, assuming construction is complete in time for the final ES. Should this not be the case, any water voles present would need to be trapped under licence, introduced to a captive breeding programme, and only re-introduced once the replacement section of rhine is suitable.
Otter Surveys will be undertaken for otter presence and the results will be presented in the final ES. The presence of otter along the rhines might require mitigation in order to avoid adverse effects on the population. Works would potentially need to avoid encroaching along the edges of the rhines, particularly if any otter holts were identified.
Terrestrial and aquatic invertebrates
Surveys will continue from those undertaken to date in order to provide invertebrate data over a full active season since spring surveys in 2013 were not undertaken.
16.9. References
Ref. 16-1 Institute for Ecology and Environmental Management (2006). Guidelines for Ecological Impact Assessment in the United Kingdom.
Ref. 16-2 Joint Nature Conservation Committee (2010). Handbook for Phase 1 habitat survey - a technique for environmental audit
Ref. 16-3 Institute of Environmental Assessment (1995). Guidelines for Baseline Ecological Assessment
Ref. 16-4 Parsons Brinckerhoff (2012). Seabank Power Station Extended Phase 1 Habitat Survey.
Ref. 16-5 Gilbert, G., Gibbons, D.W. & Evans, J.(1998). Bird Monitoring Methods. RSPB, Sandy.
Seabank 3 PEI Report – Chapter 16 Ecology
May 2014 Page 16-53
Ref. 16-6 Environment Agency (2011). H1 Annex F – Air Emissions v 2.2.
Ref. 16-7 Cresswell Associates (2010). Severnside/ Avonmouth Wetland Habitat Project: Stage 1 – Distribution of Wetland Birds within the Study Area.
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17. Landscape and Visual
17.1. Introduction
17.1.1. This chapter describes the likely effects of the Proposed Development upon
landscape character and visual amenity of the DCO Site and the surrounding
area. The assessment is based on a thorough understanding of the baseline
conditions obtained through desk study and site visits. In addition to a
photographic record of the study area, a variety of published material has been
collected, as listed in the references section of this chapter.
17.1.2. An iterative assessment and design process has been followed which seeks to
reduce, offset or compensate for predicted effects on landscape character and
views. Mitigation is proposed to minimise significant adverse effects remaining
after that process and to seek to reduce residual impacts where possible.
17.1.3. The assessment makes use of photographs, which are referred to in the text to
assist in describing the character of the DCO Site and the wider study area and
existing views. Accurate, verifiable photomontages are used to describe the likely
visual effect of the Proposed Development on a series of representative views
which have been agreed with SGC and BCC. Photographs are also used in some
cases to explain where and why the Proposed Development is not likely to be
visible. Photographs used in this PEI Report were taken in early spring 2013 and
will be updated in the final ES.
Consultation
17.1.4. A Scoping Report was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on the proposed structure, EIA
methodology and content of this chapter.
17.1.5. The Planning Inspectorate issued a formal Scoping Opinion in March 2013. A
summary of stakeholder comments and how they have been incorporated into
this PEI Report chapter are provided in Table 17-1.
Table 17-1: Relevant Scoping Opinion Responses
Stakeholder Comment Addressed within the Report
Planning Inspectorate
The ES should describe the Zone of Theoretical Visibility (ZTV) provide information on the area covered and the timing of any survey work and the methodology used.
See section 17.2 and section 17.3
The ZTV should seek to ensure that all potential sensitive receptors are considered.
See section 17.2 and section 17.3
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Stakeholder Comment Addressed within the Report
Consideration should be given to the need for landscape screening such as tree planting or bunding.
See section 17.5
SGC An overall landscape strategy should be included in the ES. The EIA should consider not only on site but any offsite mitigation that may be considered necessary
See section 17.5
A Landscape Strategy will also be necessary to cover associated development, such as pipelines, grid connections and access roads and access points.
See section 17.5
BCC No specific comments. -
NE The EIA should include a full assessment of the potential impacts on local landscape character using landscape assessment methodologies.
See section 17.2 and section 17.3
The landscaping scheme should be of a sympathetic design to break up views of the station as well as restore naturally occurring BAP habitats that have become degraded in recent years e.g. floodplain grass, hedges, reedbeds, open water.
See section 17.5
Gloucestershire County Council
The landscape character of the Forest of Dean District and the County of Gloucestershire should be considered as part of the South Gloucestershire's Landscape Character Assessment SPD.
See section 17.3
17.1.6. Following Scoping, a Technical Note was issued to SGC and BCC in March 2013
to agree the viewpoint locations and approach to the assessment. The agreed
viewpoints, locations from which photomontages would be produced, and
methodology are discussed in detail later in this chapter.
Legislation and Planning Policy Context
17.1.7. A summary of legislation and planning policy relevant to this assessment is
provided in Appendix C: Volume II of this PEI Report.
17.2. Assessment Methodology and Significance Criteria
Overview
17.2.1. The method of landscape and visual impact assessment for the Proposed
Development has been devised to address the specific impacts likely to result
from a development of its scale and nature. The methodology draws upon the
following established best practice guidance:
• Guidelines for Landscape and Visual Impact Assessment 3rd Edition
(Landscape Institute and Institute of Environmental Management and
Assessment, 2013) (Ref. 17-1);
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• Landscape Character Assessment: Guidance for England and Scotland
(Countryside Agency and Scottish Natural Heritage, 2002) (Ref. 17-2);
and
• Landscape Institute Advice Note 01/11: Photography and photomontage
in landscape and visual impact assessment (Landscape Institute, 2011)
(Ref. 17-3).
17.2.2. The assessment of impacts on built heritage, including impacts on the setting of
listed buildings, is covered in Chapter 15: Archaeology and Cultural Heritage of
this PEI Report.
17.2.3. Initial desktop study and site survey for the scoping report identified a study area
to a maximum of 10km from the boundary of the Proposed Development Site.
This range was considered a reflection of the maximum extent to which the
Proposed Development may materially influence the existing visual amenity and
allow views from across the Severn Estuary in Wales to be considered. In
contrast, a smaller study area of 5km from the boundary of the Proposed
Development Site is proposed for assessing landscape character. Beyond this
distance it is anticipated that the Proposed Development would be unlikely to give
rise to significant landscape effect. This study area was agreed with SGC and
BCC following Scoping.
17.2.4. A detailed study of the existing landscape components, character and views of
the DCO Site and the study areas has been carried out in consideration of the
following:
• Site context;
• Topography;
• Vegetation;
• Roads, public rights of way and access;
• Settlement and land-use;
• Landscape character; and
• Representative views.
17.2.5. This is supported by tables, drawings and photographs as appropriate. The
planning context with respect to landscape character and visual amenity has also
been assessed, taking into account relevant European, national, regional and
local planning policies. The baseline study forms the basis of the assessment of
the predicted impacts of the Proposed Development.
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Terminology
17.2.6. This section provides an explanation of the terminology used throughout this
assessment:
• Landscape Character Areas (LCAs) are areas of relatively homogenous
landscape character. They are defined by the combination of elements
that contribute to landscape context, character and value. Typical
landscape elements include landform, land cover, vegetation and
settlement pattern. More subjective criteria are also considered such as
scale, unity and enclosure.
• Zone of Theoretical Visibility (ZTV) provides graphical representation of
places within the study area where the Proposed Development could
potentially be visible from. The ZTV is the area within which the Proposed
Development could have an influence or effect on visual amenity. ZTVs
are generated by computer by analysing a model of the Proposed
Development and a bare ground Digital Terrain Model (DTM), which might
or might not take into account the effect of vegetation and buildings.
• Visual receptors are special interest or viewer groups who would have
views of the Proposed Development. Visual receptors are identified
through interrogation of the ZTV and field work. As the study area for this
assessment is large, views for visual receptor groups are presented as a
series of photographs selected to best represent a range of views
selected from within the ZTV.
17.2.7. The EIA process requires that a clear distinction is drawn between landscape and
visual impacts:
• Landscape impacts relate to the degree of change to physical
characteristics or components of the landscape, which together form the
character of that landscape, e.g. landform, vegetation and buildings.
• Visual impacts relate to the degree of change to an individual receptor’s
view of that landscape, e.g. local residents, users of public footpaths or
motorists passing through the area.
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Landscape Character Assessment Methodology
17.2.8. The assessment of landscape impacts has been structured around the
identification of LCAs. Within the 5km study area for landscape character
assessment it is possible to identify three categories of areas experiencing
different levels of impact: firstly there are areas where development would take
place resulting in direct effects; secondly there are areas where there is a degree
of intervisibility between the DCO Site and the surrounding landscape causing
indirect effects; and thirdly there are areas where no change would be
perceptible.
17.2.9. Each LCA has been assigned a sensitivity based on the character and quality of
the existing landscape and its ability to accommodate change. Sensitivity of LCA
is classified as Very High, High, Medium or Low, as follows:
• Very High: landscape of unique components and characteristics, sensitive
to any change;
• High: landscape of relatively distinctive components and characteristics,
sensitive to small changes;
• Medium: landscape of relatively common components and characteristics,
reasonably tolerant of changes; and
• Low: landscape of relatively inconsequential components and
characteristics, the nature of which is potentially tolerant of substantial
change.
17.2.10. The magnitude of potential change is determined through a combination of the
size/scale of the development, the geographical extent of the area influenced, the
type of development, the level of integration of new features with existing
elements, and its duration and reversibility. Magnitude of potential change is
classified as High, Medium, Low, or Neutral, as follows:
• High: ranging from a limited change in landscape characteristics over an
extensive area influencing several LCAs, to an intensive change over a
more limited area;
• Medium: ranging from a limited change in landscape characteristics at the
scale of the LCA within which the project lies, to a moderate change in a
localised area;
• Low: a limited change in landscape characteristics at the level of the
immediate setting of the site and the site itself; and
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• Neutral: no change discernible in any component.
17.2.11. The assessment also considers potential impacts on the designated landscapes
Registered Park and Gardens in the southeast of the 10km scoping area.
Visual Assessment Methodology
17.2.12. It is widely accepted that visual effects tend to decrease with distance. For the
purposes of this assessment, the extent of potential views within the study area
(i.e. within a radius of up to 10km of the Proposed Development for visual effects)
has been determined. The resulting ZTVs for both the HRSG building envelope
(maximum height 45m above the finished ground levels (up to 53.5m AOD)) and
the two main stacks (of 90m height or up to 98.5m AOD) of the Proposed
Development have been reviewed by desk study and fieldwork against the
following criteria in order to determine the selection of representative views which
form the basis of the visual assessment:
• Receptor function / activity;
• Distance from the Site;
• Topography and elevation;
• Degree and period of exposure;
• Designation of the viewing place; and
• Distribution of receptors.
17.2.13. Representative viewpoints cover a range of receptor groups and locations from
close, middle and long distance and have been selected to adequately illustrate
the effect of the Proposed Development. Viewpoints and the location of
photomontages of the Proposed Development have been discussed and agreed
with SGC and BCC.
17.2.14. Visual receptors (based on representative views) have been assigned a category
of sensitivity based on a combination of the activity and expectations of the
predominant receptor type (e.g. residents, recreation, work etc.) and the location,
context and importance of the existing view. Sensitivity of receptors is classified
as Very High, High, Medium or Low, as follows:
• Very High: activity resulting in an exceptional interest or appreciation of
the view (e.g. people visiting to appreciate a recognised view) and/or a
very high value of existing view (e.g. Viewpoint from scheduled
monument):
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• High: activity resulting in a high interest or appreciation of the view (e.g.
residents or people engaged in outdoor recreation whose attention is
focussed on the landscape) and/or a high value of existing view (e.g. a
designated landscape or unspoilt countryside);
• Medium: activity resulting in a medium interest or appreciation of the view
(e.g. people engaged in outdoor recreation that does not focus on an
appreciation of the landscape) and/or a medium value of existing view
(e.g. suburban residential areas or intensively farmed countryside); and
• Low: activity resulting in a low interest or appreciation of the view (e.g.
people at work or motorists travelling through the area) and/or low value
of existing view (e.g. industrial areas or derelict land).
17.2.15. The magnitude of visual change is determined through a combination of the
degree of change to the view resulting from the Proposed Development, including
the extent of the area over which the changes would be visible, the period of
exposure to the view and reversibility. Magnitude of change is classified as High,
Medium, Low or Neutral, as follows:
• High: high degree of change to existing view (e.g. loss of characteristic
features) and/or high degree of exposure to view (e.g. close or open
views);
• Medium: medium degree of change to existing view (e.g. partial loss of
characteristic features) and/or medium degree of exposure to view (e.g.
middle-distance or partial views);
• Low: low degree of change to existing view (e.g. limited loss of
characteristic features) and/or low degree of exposure to view (e.g. long-
distance, interrupted or glimpsed views); and
• Neutral: no change discernible in existing view.
17.2.16. Accurate Visual Representations of the Proposed Development for representative
views (visual receptors) have been produced in line with the Landscape Institute
guidance (Advice Note 01/11) (Ref. 17-3)
Temporal Assessment
17.2.17. The potential effects of the Proposed Development upon the existing (baseline)
landscape character, and receptors’ views of that landscape, have been
identified and assessed at three points in time:
• During construction (currently expected to be 2017 – 2021);
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• On completion (currently expected to be 2021) – Year 1; and
• Following 15 years of operation (currently expected to be 2036) – Year
15.
17.2.18. Through the assessment of impacts at these stages, distinctions have been
drawn between temporary, permanent and residual impacts. Landscape and
visual effects are further categorised as being either direct (e.g. introduction of
built forms), or indirect (e.g. off-site visual impact of construction traffic).
Significance of Effects
17.2.19. Whilst there is inevitably a degree of professional judgement involved in
determining the levels of significance of landscape and visual effects, they can
broadly be determined by the interaction of the sensitivity of receptor and
magnitude of impact. This interaction results in categorisation of effects as shown
in Table 17-1. Effects are generally considered significant (and in need of
mitigation) if they are major or moderate.
17.2.20. Minor and negligible effects are not considered to be significant. A neutral
magnitude of change will always result in a negligible effect.
Table 17-1: Classification of Landscape and Visual Effects
Magnitude of Change
Sensitivity of Receptor
Very High High Medium Low
High Major Major Moderate Minor
Medium Major Moderate Minor Negligible
Low Moderate Minor Negligible Negligible
Neutral Negligible Negligible Negligible Negligible
17.2.21. Environmental effects are further identified as being either beneficial or adverse.
A textual description of landscape and visual effects is presented in Table 17-2.
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Table 17-2: Description of Landscape and Visual Effects
Classification of Effect
Description of Landscape Effect Description of Visual Effect
Major beneficial effect
Where the Proposed Development would enhance the scale, landform and pattern of the landscape and/or enrich quality or characteristic feature
Where the Proposed Development causes a clearly significant improvement in the existing view
Moderate beneficial effect
Where the Proposed Development is characteristic of the scale, landform and pattern of the landscape, and/or enhances quality or characteristic features
Where the Proposed Development causes noticeable improvement to the existing view
Minor beneficial effect
Where the Proposed Development fits with the scale, landform and pattern of the landscape and/or quality or characteristic features.
Where the Proposed Development causes a slight improvement to the existing view
Negligible
Where the Proposed Development causes scarcely any perceptible deterioration or improvement to the existing landscape; or
No effect occurs.
Where the Proposed Development causes scarcely any perceptible deterioration or improvement to the existing view; or
No effect occurs.
Minor adverse effect
Where the Proposed Development does not fit with the scale, landform and pattern of the landscape and/or detracts from quality or characteristic features.
Where the Proposed Development causes slight deterioration to the existing view.
Moderate adverse effect
Where the Proposed Development is not characteristic of the scale, landform and pattern of the landscape, and/or damages quality or characteristic features
Where the Proposed Development causes noticeable deterioration to the existing view
Major adverse effect
Where the Proposed Development is at considerable variance with the scale, landform and pattern of the landscape and/or is considerably detrimental to quality or characteristic features
Where the Proposed Development causes a clearly significant deterioration in the existing view.
Key Parameters for Assessment
17.2.22. The exact layout and dimensions of the Proposed Development are not fully
determined at this stage; as such this assessment has been undertaken in line
with the Planning Inspectorate Guidance Note 9 ‘Using the Rochdale Envelope’
(Ref. 17-4).
17.2.23. The focus of the assessment within this chapter is to assess the worst-case
scenario, which, for landscape and visual effects, is typically considered to be the
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maximum building sizes that may be consented under the scheme. However,
where the minimum parameters would affect the conclusions of the assessment
this is highlighted. For example, the peaking plant units may not be enclosed
within a building if OGCTs are selected, which would result in a structure that is
more industrial in appearance however noticeably smaller in footprint and height.
17.2.24. It is considered that the effects of anything less than the maximum parameters
would be similar to or less than the assessment presented in this chapter. This
should be the case for example if the final design incorporates only one stack for
example, rather than the two main stacks and two peaking plant stacks that have
been assessed.
17.2.25. The final design and appearance of the buildings and structures cannot be
finalised until detailed design has been undertaken, post consent and once the
Principal Contractor has been selected. The photomontages therefore present a
‘worst-case’ which reflects the maximum parameters to be consented under the
Rochdale Envelope, and with minimum design input (in accordance with the
Design Code which will be submitted as part of the DCO Application). They
therefore show no substantial architectural treatment.
17.2.26. To facilitate the reader’s interpretation of the information, the photomontages
illustrate the maximum parameters for both the single-shaft and multi-shaft
configurations.
17.3. Baseline Conditions
17.3.1. This section describes the existing conditions onsite and in the surrounds, based
on a baseline situation pre-December 2013, as discussed in Chapter 2: The DCO
and EIA Process. It focuses on the Proposed Development Site, given that the
visual effects associated with the proposed cooling water pipeline and electrical
connection will be substantially less than for the Proposed Development.
Study Area and Site Context
17.3.2. The assessment considers the potential effects of the Proposed Development,
both in terms of changes within the Proposed Development Site and the Other
DCO Land, as described in Chapter 4: Project Description. Given the Other DCO
Land will constitute an underground water pipeline and a short length of electrical
connection (approximately 440m) within the Seabank 1 & 2 generating station,
the elements of primary interest in the context of the Landscape and Visual
impact assessment will take place within the Proposed Development Site.
17.3.3. The Proposed Development Site covers an area of approximately 19ha and is
located on land immediately adjacent to the existing Seabank 1 & 2 generating
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station (illustrated in Figure 17-1, Volume III of this PEI Report). The Proposed
Development Site is approximately 5km northwest of Avonmouth in an area
called Crook’s Marsh in Severnside approximately 10km to the east of Bristol city
centre.
17.3.4. A detailed description of the site and surrounds is presented in Chapter 3: The
Site and Its Surroundings. A summary relevant to this assessment is presented
below.
Topography and Drainage
17.3.5. The topography of the 10km study area is illustrated in Figure 17-2, Volume III of
this PEI Report. The DCO Site is located within an area known as Crook’s Marsh
and is a flat open area of floodplain at approximately 5.5m and 7m AOD,
intersected by rhines (drainage ditches). To the west, the other side of the raised
embankment of the flood defence wall is the Severn Estuary. In contrast to the
east a north-south ridgeline, marks the edge of the marshland and floodplain,
beyond which to the east are the rolling hills of Bristol and Gloucestershire. The
Welsh hills are evident to the west on the far side of the Severn Estuary.
17.3.6. To the south the floodplain continues to the mouth of the River Avon, which forms
a dramatic gorge as it passes through the rolling hills of Bristol to the southeast.
South of the River Avon, the floodplain is less defined with low hills forming
shallow cliffs to the estuary as it widens out into the sea to the southwest.
Vegetation
17.3.7. The DCO Site lies in an area of flat agricultural floodplain which is pasture if
used. Within this area there are relatively few areas of trees and shrubs with only
a few remnant hedgerows and patches of scrub scattered across the landscape.
Away from the agricultural floodplain, several of the near-by recent industrial
developments have included significant areas of landscape. This includes the
Western Approach Distribution Centre to the north and the existing Seabank 1 &
2 generating station. Both have sought to enhance local habitats by planting
native trees and shrubs along realigned rhines and sustainable drainage systems
to recreate pockets of the natural landscape of the area. Other local
developments have adopted more modest landscapes of trees and shrubs within
amenity grass.
17.3.8. Woodland is more common on the ridgeline to the east. A mosaic of farmland,
historic parkland, woodland and urban development covers the ridge and the hills
to the east.
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Transport Links
17.3.9. The Proposed Development Site lies in an area surrounded by several major
roads including the M49 Motorway link approximately 1km to the south and east,
the A403 (between Avonmouth and Severn Beach) approximately 400m to the
north and west, the M5 2.2km to the south and east, and the M4 approximately
7km to the north and east. The Severn Bridge linking England to Wales is
approximately 3km to the north and the Severn Road Bridge 7.5km the north.
17.3.10. A number of public rights of way are in the vicinity of the Proposed Development
Site, with the nearest ceasing at the southern boundary of the Site. The Severn
Way long distance footpath runs along the A403 to the west and The Community
Forest Path is along the ridgeline to the east.
17.3.11. Local train lines and stations are discussed in Chapter 10: Traffic and Transport.
Settlement and Land Use
17.3.12. The surrounding area between Avonmouth and Severn Beach (along the A403)
is in mainly industrial use, home to numerous chemical and pharmaceutical
works, industrial parks and distribution centres. There are few residential
properties in the area with a ring of settlements 2km from the Proposed
Development Site to north, east and south. These include Severn Beach, Marsh
Common, Compton Green, Berwick and Hallen. Other nearby settlements are
Pilning, 2.2km to the northeast, and Easter Compton 3km to the east.
17.3.13. The Proposed Development Site is surrounded by existing and proposed
development. To the southwest of the Proposed Development Site is the existing
Seabank 1 & 2 generating station, which was constructed on the site of gas
works that was built in the 1980s. Two wind turbines have recently been
constructed to the southwest of Seabank 1 & 2. To the north is the demolished
former ICI / Terra Nitrogen works, on which another developer has aspirations for
a separate power station. To the northwest a third party is currently building the
Severnside Energy Recovery Centre and Bottom Ash Facility. To the northeast, a
large area known as Central Park is being developed for a number of distribution
warehouses. To the southeast of the CCR Site is the Avonmouth LNG Storage
Facility.
17.3.14. Development under construction or with planning consent will be discussed in the
section Cumulative Effects. A list of these cumulative projects is provided in
Chapter 7: Assessment Methodology.
17.3.15. Apart from industrial and commercial development, the surrounding area is a mix
of agricultural land, small pockets of woodland along the ridgeline and scrub and
mudflats along the shoreline of the River Severn.
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17.3.16. The area is crisscrossed by numerous pylons carrying overhead power lines
which together with other industrial infrastructure are key characteristics of the
landscape. Within the Proposed Development Site, there are pylons carrying
11kV, 132kV and 400kV overhead electrical lines crossing the CCR Site. Two
underground gas mains and a water pipe run along the southerly edge of the
Proposed Development Site.
Landscape of the DCO Site
17.3.17. The existing DCO Site is illustrated in Figure 17-3 (Volume III of this PEI) and
photographs (taken in August 2012) on Figures 17-4 and 17-5 (Volume III).
Figure 17-6 illustrates the local landscape character areas which are discussed
below.
Landform and Drainage
17.3.18. The DCO Site is generally flat, with some mounding in places. This mounding
may possibly result from clearance of previous development or to protect the
development from flooding on adjacent land. The Red Rhine runs along the
southern boundary of the CCR Site and through the centre of the Generating
Station Site, in an east to west direction. Other minor rhines are scattered
through the Proposed Development Site and DCO Site. These all drain the land
and feed into the River Severn to the west.
17.3.19. The Red Rhine is currently being realigned to run along the northern boundary of
the Proposed Development Site by a third party, Severnside Distribution Land
Ltd, as discussed in Chapter 7: Assessment Methodology. The same developer
is also currently constructing a Spine Access Road immediately north of the
realigned Red Rhine.
Vegetation
17.3.20. The flat open floodplain of the DCO Site is predominantly rough pasture broken
up into a rectangular field pattern by rhines (drainage ditches).
17.3.21. Patches of scrub are scattered across the Proposed Development Site,
particularly in the northern part and beside the rhines. Trees are few with only the
occasional relatively stunted specimen and a small area of trees and shrubs on
the edge of the Proposed Development Site beside the southern boundary. The
area has a neglected feel suggesting the pasture is not used for regular grazing.
Landscape Character
17.3.22. The character of the landscape of the 5km study area has been extensively
studied at a number of levels. In order to provide context to the Proposed
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Development this section reviews and summarises the existing published
landscape character assessments at the national and local levels. In the Potential
Effects and Mitigation Measures section of this chapter the effects of the
Proposed Development are then assessed against LCAs defined at a local level
specifically for this assessment.
National Landscape Character
17.3.23. At the national level LCAs within the study area have been described based on
National Character Areas (NCA) defined and described by Natural England.
Whilst providing landscape context, NCAs do not provide sufficient detail on
which to assess the impact of the Proposed Development.
17.3.24. NCAs divide England into 159 natural areas each defined by a unique
combination of landscape, biodiversity, geodiversity and economic and cultural
activity.
Severn and Avon Vales NCA 106
17.3.25. The DCO Site is located within the Severn and Avon Vales NCA 106 (Ref. 17- 5)
and has the following description:
“The lower valleys of the rivers Severn and Avon dominate this low lying
open agricultural vale landscape made up of distinct and contrasting vales,
punctuating the otherwise flat vale landscape. The M5 Motorway runs
through the centre and the eastern edge of the area. A small proportion of
the National Character Area (NCA) is urban and industrial development is
still important at Avonmouth The majority of the area is used as agricultural
land. Woodland is sparse and it is a generally open landscape.”
17.3.26. Key characteristics of relevance are:
• “Fields on the floodplains are divided by ditches (called rhines south of
Gloucester) fringed by willow pollards and alders.
• Pasture and stock rearing predominate on the floodplain
• Along the main rivers, floodplain grazing marsh is prevalent.
• The River Severn flows broadly and deeply between fairly high banks,
north to south. The main rivers regularly flood at times of peak rainfall.”
Bristol, Avon Valleys & Ridges NCA 118
17.3.27. To the east of the DCO Site, the ridges and hills around Bristol are within NCA
118 – Bristol, Avon Valleys and Ridges (Ref. 17- 6). This NCA extends from the
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Severn and Avon Vales to the west to the Cotswolds in the east. The landscape
is described as enclosed within an often gently undulating landform. The
hedgerow pattern is variable with woodlands mainly on steep valley sides.
Settlement is very dense, as many villages have become enlarged as commuter
settlements and have abrupt edges with the countryside. Key characteristics of
relevance to the study area are:
• “A landscape of very mixed landform, geology and settlement pattern,
strongly influenced by the Avon Valley, Bristol at its centre and by its
industrial history.
• Frequent large villages, small towns and major conurbations but also
undisturbed rural areas.
• Wooded scarps – with ancient woodland – and high, open, downland
ridges.
• Frequent parks, mansions and manor houses.”
Local Landscape Character
17.3.28. A district landscape character assessment covers the northern part of the 5km
study area within South Gloucestershire. The South Gloucestershire Landscape
Character Assessment (2005) (Ref. 17-7) is currently under review with a draft
review published in January 2014 (Ref. 17-8). For the purposes of this
assessment the 2005 assessment has been used, although the assessment has
noted proposed changes in the draft review where it has a bearing on the
potential effects and mitigation measures.
17.3.29. No similar district wide assessment is available for Bristol City and for the
purposes of this PEI Report LCAs have therefore been defined for the part of the
study area within Bristol City.
17.3.30. The 5km study area does not extend into North Somerset District,
Monmouthshire, Forest of Dean District and the County of Gloucestershire.
Landscape character assessments relevant to these areas are not considered in
this assessment.
17.3.31. Table 17-3 provides a summary of the local LCAs within the 5km study area and
descriptions of each LCA are provided in Appendix L Part 2, Volume II of this PEI
Report. Each LCA has been renumbered 1 to 8 and assigned a sensitivity based
on the district assessment and site survey.
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Table 17-3: Summary of Local Landscape Character
EIA LCA Number LCA Name Sensitivity
LCA 1 Pilning Levels Medium
LCA 2 Severn Ridges High
LCA 3 Patchway and Filton Medium
LCA 4 Henbury and Kingsweston High
LCA 5 Hallen Marsh Medium
LCA 6 Avonmouth Low
LCA 7 River Severn Very High
LCA 8 Severn Shoreline and Estuary Very High
Summary of Landscape Character
17.3.32. The DCO Site falls within NCA 106: Severn and Avon Vales defined by Natural
England. To the east, NCA 118 Bristol, Avon Valleys and Ridges whose rolling
hills contrast sharply with the flat floodplain landscape of the vales to the west.
This distinct change in landscape character is reflected in the local landscape
character as defined by SGC and within the EIA defined landscape character
assessment.
17.3.33. The Proposed Development Site is located within LCA 1 Pilning Levels,
described as “a flat, semi-enclosed to open agricultural landscape, divided by
rhines, transport routes and punctuated by large industry.” To the east, LCA 2
Severn Ridges rises from the level ground to create an area of low hills and
radiating ridges. The flat floodplain landscape of the levels continues to the south
within LCA 5 Hallen Marsh and LCA 6 Avonmouth but increasingly is dominated
by large industry. The Severn Ridges also continues to the south within LCA 4,
Henbury and Kingsweston but is increasing dominated by residential
development closer to Bristol City Centre.
17.3.34. Both NCA 106 and LCA 1 are strongly influenced by the presence of the tidal
River Severn and estuary to the west. The extensive, open landscape of tidal
wetlands, mudflats and rock creates a constantly changing shoreline within
characteristic expansive views.
17.3.35. The landscape character of the 5km study area is varied comprising a number of
different landscape types. Sensitive landscapes are dispersed throughout, with
the wooded ridge landscape of the Severn Ridges to the east, the estuary
landscape of the River Severn to the west and the remnants of agricultural
floodplain landscape of the Levels in the centre. To the east and west, landscape
features often remain intact within these areas, however, the landscapes suffer
from development usually outside the area, interrupting views and disturbing
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tranquillity. The influence of the major transport routes, industry and urban areas
on the surrounding landscape is obvious, compartmentalising it into distinct areas
between transport routes and landform.
17.3.36. Located beside the existing Seabank 1 & 2 generating station and the recently
demolished ICI / Terra Nitrogen works, the Proposed Development Site is
currently unused and grassland. It is criss-crossed by pylons carrying overhead
power lines and pipelines with rough grassland and patches of scrub. Coupled
with the tall chain link fencing bounding the Proposed Development Site, fly
tipping and other signs of disuse, the area appears abandoned.
Visual Amenity
Visibility within the Study Area
17.3.37. ZTVs of the proposed HRSG building envelope and two stacks (90m height) have
been generated by computer modelling as depicted in Figures 17-7 and 17-8
(Volume III of this PEI). The effect of existing buildings and groups of trees and
shrubs has not been included. The percentage visibility of parts of the stacks has
also been considered within the 10km study area.
17.3.38. Individual receptors with possible views of the Proposed Development have been
identified within the proposed ZTVs and verified by on-site survey. The receptors
have been allocated to receptor groups according to their sensitivity (Very High,
High, Medium or Low) to changes in visual amenity. A schedule of visual
receptors is included in Appendix L, Part 2, Volume II of this Report.
17.3.39. Table 17-4 provides a summary of the representative views and visual receptors.
Table 17-4: Visual Receptors and Representative Views
Receptor Number and Name Sensitivity Representative View Number and Name
1a. Users of PROW beside the River Severn
Medium Representative View 1 - View from the river bank at Caldicot looking southeast
1b. Travellers crossing the Severn Bridge
Low
2a. Travellers using Holloway Road
Low Representative View 2 - View from Holloway Road bridge as it crosses over M49 looking southwest 2b. Workers in warehouses along
Holloway Road Low
3a. Users of Community Forest PRoW crossing over the M5
Medium Representative View 3 - View from bridge carrying Community Forest Path over M5 looking northwest
4a. Users of Community Forest PRoW as it travels along the ridge of Spanorium Hill
Medium Representative View 4 - View from Community Forest Path as it crosses Spanorium Hill looking northwest
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Receptor Number and Name Sensitivity Representative View Number and Name
5a. Users of Blaise Castle public park
Medium Representative View 5 - View from beside Blaise Castle looking northwest
6a. Users of PROWs through Kingsweston public park
Medium Representative View 6 - View from footpath leading up to Kingsweston House looking north 6b. Users of Kingsweston House Medium
7a. Travellers crossing the Severn Road Bridge (M48)
Low
Representative View 7 - View from footpath crossing Severn Road Bridge (M48) looking south
7b. Users of PROW crossing the Severn Road Bridge (M48)
Medium
8a. Residents in properties along riverfront at Portishead
High
Representative View 8 - View from promenade along riverfront at Portishead looking northeast
8b. Users of promenade at Portishead
Medium
9a. Travellers along the A403 Low
Representative View 9 - View from pavement running along A403 looking southeast
9b. Users of PROW along the A403 and cyclepath
Medium
10a. Users of PROW crossing Crook’s Marsh
Medium Representative View 10 - View from PROW crossing Crook’s Marsh looking northwest
11a. Users along the Severn Way PRoW
Medium Representative View 11 - View from Severn Way along river wall at Severn Beach looking south 11b. Residents in properties along
the riverfront at Severn Beach High
17.3.40. Descriptions of the views for each visual receptor are provided in Appendix L,
Part 2, Volume II of this Report and illustrated by means of photographs taken
from 11 representative viewpoints.
17.3.41. The locations of the representative viewpoints are illustrated in Figure 17-8
(Volume III of this PEI), and the photographs are included in Figures 17-9 to 17-
14 (Volume III). These have been located at publicly accessible vantage points to
represent as closely as possible the actual view for each receptor. Where
possible, the actual view is presented but otherwise, when for example
intervening vegetation blocks views, locations have been chosen at nearby
gateways and gaps in vegetation to demonstrate the experience of the receptor
as if the vegetation was removed. In response to a request from SGC,
representative views have been located at Holloway Road, within the Western
Approach Distribution Centre (Representative View 2), the bridge over the M5
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carrying the Community Forest Path (Representative View 3) and from the
Severn Way footpath at Severn Beach (Representative View 11).
17.3.42. Photomontages of the Proposed Development at Year 1 and following 15 Years
of Operation for three of the 11 representative views (Representative Views 4, 10
and 11) have been produced and are discussed in the following section, Potential
Effects and Mitigation Measures. Both options, the single-shaft and multi-shaft
development, are shown on separate photomontages. These are presented in
Figures 17-16 to 17-30 (Volume III of this PEI) and their locations indicated on
Figure 17-8 (Volume III). Viewpoints and the location of photomontages of the
Proposed Development have been established in consultation with SGC and
BCC.
Summary of Baseline Views
17.3.43. The Proposed Development Site is located within the flat open landscape of the
Pilning or Severn Levels with open direct views across the area from high ground
to the east. In contrast, the flatness of the landform restricts visibility from the
north, south and west with vegetation and development screening the majority of
direct views at ground level.
17.4. Development Design and Impact Avoidance
17.4.1. The design of the Proposed Development is largely based upon the technical
requirements of the scheme, however informal consultation responses in respect
to the finishes of the Proposed Development have been taken into account.
17.4.2. Chapter 6: Project Need and Alternatives provides an explanation of the design
evolution to take into account the need for landscaping onsite. In particular, the
cooling water systems were realigned during the later stages of development to
enable the turbine buildings and HRSG buildings to move south, enabling a row
of tall landscaping to be incorporated in the design along the northern boundary
of the Site.
17.4.3. An area of landscaping has also been integrated into the design along the
proposed PROW that connects Ableton Lane and the existing roundabout east of
the Proposed Development Site. Additional space was also made available in
later designs for tree planting between the peaking plant and CCR Site to break
up views from the east.
17.4.4. The final design may incorporate additional measures to mitigate landscape and
visual effects, such as green or brown roofs and architectural treatment, as well
as minimising the building massing and heights; however for the purpose of this
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assessment it was deemed appropriate to present the worst-case situation, as
discussed earlier.
17.4.5. As described in Chapter 4: Project Description, the electrical connection will be
routed through the Seabank 1 & 2 station on a cable rack approximately 2m
above the ground or buried underground for the 440m distance to Seabank
Substation. The avoidance of an overhead line and routing the line through
Seabank 1 & 2, where it will blend into the background of industrial structures, is
considered to fully mitigate the effects of the electrical connection.
17.5. Potential Effects and Mitigation Measures
17.5.1. The assessment of effects relies on field data collected during autumn 2012 and
winter 2013. Field surveys recorded existing baseline data and assessed the
likely impacts of the Proposed Development on the landscape character within a
5km radius of the DCO Site and for visual receptors within a 10km radius of the
DCO Site.
Construction Phase
17.5.2. The enabling works and construction of the Proposed Development is expected
to take approximately 54 months to complete, if built in a single phase. The
nature of construction means that impacts on the character of the surrounding
landscape and surrounding views are inevitable, albeit temporary in nature. The
construction of the Proposed Development would involve a number of activities
that have the potential to impact on landscape and views. These include the
following:
• Site clearance operations, including the removal of some existing
vegetation;
• Realignment of the Abson gas pipeline that currently runs through the
centre of the proposed development site;
• Raising of the ground level of the Generating Station Site and land re-
profiling to proposed contours by importing material into the Proposed
Development Site;
• Establishment and subsequent presence of a construction compound,
security fencing and temporary working areas throughout the construction
period;
• Traffic management signs and equipment;
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• Construction of temporary haul roads and hard-standings and removal at
the end of the construction period;
• Excavation and temporary stockpiling of soils and demolition materials for
re-use, including along the proposed cooling water pipeline corridor;
• Construction machinery, plant and vehicles accessing and moving across
the Site;
• Passage of heavy construction plant and delivery vehicles on the local
road network;
• Erection and operation of temporary cranes, cement silos, scaffolding etc.;
• Civil engineering works, including construction of foundations, concrete
slabs, access roads and drainage;
• Construction of the steel building structure and subsequent cladding;
• Installation and commissioning of process plant items; and
• Service installations including pipe/cabling, electrical connection and
water pipe (further details are provided in Chapters 4 and 5).
Landscape Effects of Construction
17.5.3. The change during construction and the resulting effect is described for each
local LCA within the 5km study area in Appendix L Part 3, Volume II of this PEI
Report. The construction of the Proposed Development would result in a number
of direct and indirect effects on the landscape character of the 5km study area as
discussed below.
Direct Effects
17.5.4. LCA 1 would be directly affected by the construction of the Proposed
Development and proposed cooling water pipeline. The majority of the DCO Site
is located within the LCA and the existing rough grassland and scrub would be
replaced by construction activities. The change in character of the DCO Site
would be seen within the context of similar activity on adjacent industrial and
construction sites. The southern part of the LCA is characterised by industrial
developments and the construction works would follow this pattern.
17.5.5. In addition to construction works within LCA 1, the proposed cooling water
pipeline would be installed along the northern boundary of LCA 5. Again this area
is characterised by industrial development and though the construction works
would result in disturbance to the existing agricultural land, they again would be
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in the context of other industrial developments and the numerous pylons with
overhead power lines and pipelines crossing the LCA. The works would be
comparable to small-scale road works and their character would reflect typical
maintenance that frequently occurs within the industrial context.
17.5.6. An increase in construction vehicle movements in LCA 1 and 5 away from the
DCO Site is also possible, although the likely relative impact of this would be
limited by the fact that the existing activities in Avonmouth and the surrounding
area already result in more vehicle movements than might otherwise be expected
on local roads.
17.5.7. LCA 1 and LCA 5 have a Medium sensitivity to change and the construction
phase would cause a Medium magnitude of change resulting in a minor adverse
temporary landscape effect, which is not considered to be significant.
Indirect Effects
17.5.8. Enabling works and construction activities would occur across the DCO Site over
an expected 54 month period. During that time, construction traffic may result in
increased vehicle movements in adjacent LCAs, in particular LCA 6. The open
nature of the DCO Site would increase potential for intervisibility between LCA 1
and adjacent LCAs. The flat landform of the surrounding area however results in
local screening from buildings and vegetation. This helps to limit intervisibility for
LCAs with a similar topography such as LCA 6 Avonmouth. The dense
development within LCA 6 reduces opportunities for intervisibility with LCA 1
except along the northern boundary. In addition, LCA 6 has an ever evolving
industrial character with construction works and associated traffic fluctuations
throughout the LCA. The Low impact of the construction phase on a LCA with a
Low sensitivity to change would result in a negligible landscape effect, which is
not considered significant.
17.5.9. In contrast, there is a high degree of intervisibility between LCA 1 and LCA 2,
Severn Ridges to the east of the DCO Site. Construction activities would be seen
as part of the characteristic expansive panoramic views of other industrial
developments and construction within the wider LCA 1. Beyond the western edge
of LCA 2, there would be no intervisibility with LCA 1, with the result that the
majority of LCA 2 would experience no indirect landscape impacts. LCA 2 has a
High sensitivity to change and would experience a Low adverse impact resulting
in a Minor landscape effect, which is not considered significant.
17.5.10. Landform and vegetation prevent intervisibility between LCA 1 with LCA 3, LCA
4, LCA 7 and LCA 8. Construction traffic would also not increase within these
LCAs, and as a result there would be no landscape impact, therefore resulting in
a negligible landscape effect.
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Summary of Landscape Effects of Construction
17.5.11. Due to the nature, extent and duration of the construction activities and the
character of the existing landscape identified in the eight LCAs within the 5km
study area the landscape effects would range from negligible to minor, which are
not considered significant.
17.5.12. Direct effects on landscape character would be limited to the DCO Site and the
immediate area within LCA 1 and LCA 5. The effects would result from
construction activities across the whole of the Proposed Development Site and a
series of defined areas within the DCO Site. Construction activities would include
operation of plant and machinery, access roads, hard-standings and ground
modelling. Direct effects would be temporary and not significant.
17.5.13. Impacts on landscape character of the surrounding area would diminish with
distance from the DCO Site and the cumulative screening effect of intervening
features reducing intervisibility between LCAs. Indirect effects on adjacent LCAs
would be temporary and not significant.
Visual Effects of Construction
17.5.14. The likely effects on views during construction are described in Appendix L Part
4, Volume II of this PEI Report. The main effects are discussed below.
17.5.15. Though the DCO Site is open with a number of potential close range views there
are relatively few public vantage points. Where views are available, construction
activities on the DCO Site would be seen within the context of construction and
industrial activities on adjacent sites. The removal of the rough grassland, ground
modelling and gradual emergence of the Proposed Development would be visible
in close range views for travellers and walkers along the A043 (Receptors 9a and
9b) and for walkers on PROWs on Crook’s Marsh (Receptor 10a). Views of
construction from the A403 (Receptors 9a and 9b) would be filtered by the
construction works and eventual development on the Severnside Energy
Recovery Centre. The Medium magnitude of change would result in minor
adverse visual effect which is not significant. In contrast, views from Crook’s
Marsh (Receptor 10a) would be direct within only patches of scrub on adjacent
land filtering views. The High magnitude of change would result in a moderate
adverse visual effect which is considered significant, albeit temporary in duration.
17.5.16. Construction activities would also be visible in views from elevated locations.
Users of the Community Forest PROW on Spanorium Hill (Receptor 4a) would
see the works as part of an open panoramic view across the level ground. The
loss of agricultural fields to construction works would clearly be viewed within the
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context of other construction and industrial activities within adjacent sites in the
surrounds. The distance of the receptor from the DCO Site, the nature of the view
and scale of the panorama would result in a Medium magnitude of change with a
minor adverse visual effect, which is not significant.
17.5.17. Views within the level ground away from the immediate vicinity of the DCO Site
are interrupted by buildings and vegetation. As a result only the tall construction
plant and eventually the top of the HRSG building, peaking plant and stacks
would be visible above these filtering features. Construction would result in a Low
visual change for receptors with middle distance views towards the Site, including
those within the Western Approach Distribution Park (Receptors 2a and 2b) and
in Severn Beach (Receptors 11a and 11b). Visual effects would vary from minor
adverse to negligible which are not significant.
17.5.18. Construction would not be readily apparent within distant views of the DCO Site.
Intervening features filter the views in all cases with only tall construction plant
and eventually the top of the HRSG building, peaking plant and stacks visible. In
addition, clarity of distant views is also frequently dependant on weather
conditions. The Low magnitude of change for receptors 1a, 1b, 6a, 7a, 7b, 8a
and 8b would result in a minor adverse or negligible visual effect, which is not
significant.
17.5.19. Three receptors (Receptors 3a, 5a and 6b) are enclosed by vegetation and
landform and would experience no views of construction on the DCO Site.
Summary of Visual Effects of Construction
17.5.20. Of the eighteen visual receptors identified in this PEI Report only one would
experience a significant adverse visual effect. Users of the PROW on Crook’s
Marsh (Receptor 10a) would have direct open views of construction activities on
the DCO Site. The activities would be seen within the context of other
construction work and industrial uses on adjacent sites. Though the construction
works would last an expected 54 months, construction activities are temporary
and would vary during this period. Gradually the disruption arising from
construction would be replaced with an organised industrial development similar
to adjacent developments.
Operational Phase
17.5.21. The following assessment of operational landscape and visual effects considers
changes to landscape character and visual amenity on completion of construction
of the proposed facilities in 2021 (Year 1) and 2036 (Year 15).
17.5.22. Photomontages of the Proposed Development at Year 1 have been produced
and are shown on Figures 17-16 to 17-30 (Volume III of this PEI Report). Their
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locations have been established in consultation with SGC and BCC and are
illustrated on Figure 17-8 (Volume III of this PEI Report).
17.5.23. The operational effects of the proposed cooling water pipeline are not discussed,
given that it will be underground and therefore not visible. In addition, the
proposed electrical connection may also be underground, or at low level within
the existing Seabank 1 & 2 site. The operational effects of this associated
development are therefore considered to be negligible.
Landscape Effects (Year 1)
17.5.24. The likely effects at the start of operation for each local LCA within the 5km study
area are described in Appendix L Part 3, Volume II of this PEI Report. Key effects
are discussed below.
Operation: Direct Landscape Effects (Year 1)
17.5.25. LCA 1 would be directly affected by the completed Proposed Development. The
existing flat, floodplain landscape of rough grassland and scrub would be
replaced by a large scale power station. The scale and mass of the Proposed
Development located on the open Site would have a substantial impact on the
immediate landscape character of the Proposed Development Site. However the
context of the LCA within the Levels and LCA 6, Avonmouth to the south that
includes Seabank 1 & 2 and other industrial developments with their large
warehouse-style buildings, tall stacks and wind turbines reduces the level of
impact to Low. On completion the disruption of construction would be replaced by
a new industrial development with a well-conceived design and site layout in
keeping with the surrounding landscape character of both Pilning Levels (LCA 1)
and adjacent areas (LCA 6 Avonmouth and LCA 5 Hallen Marsh). The minor
adverse landscape effect on LCA 1 is considered not significant.
Operation: Indirect Landscape Effects (Year 1)
17.5.26. The Proposed Development would to some degree, extend the influence of the
existing industrial area in terms of intervisibility between LCAs. When operational,
the Proposed Development may result in an increase in number of vehicle
movements on local roads but this would be similar to the normal fluctuations
experienced in the Avonmouth area. Detail traffic considerations are discussed in
Chapter 10: Traffic and Transport.
17.5.27. LCA 2 Severn Ridges to the east has a High sensitivity to change and the
Proposed Development would cause a Low magnitude of change resulting in a
minor adverse indirect landscape effect, which is not considered significant.
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17.5.28. LCA 5 Hallen Marsh and LCA 6 Avonmouth to the south also would experience a
Low level of change. Though the Proposed Development would be visible from
the northern part of both LCAs, buildings and vegetation within the LCAs would
limit intervisibilty. In addition the nature of the Proposed Development would
appear appropriate to its location. The negligible landscape effects are
considered not significant.
17.5.29. All other identified LCAs within the 5km study area have no intervisibility and
would experience no landscape effects.
Summary of Landscape Effects on Completion (Year 1)
17.5.30. Of the eight LCAs identified in the 5km study area only one would be directly
affected by the operation of the Proposed Development. The effect on landscape
character is considered not significant in the context of the adjacent industrial
area within the Levels. The Proposed Development would be carefully located
within the existing landscape framework of the floodplain and would introduce a
new industrial development in character with the surrounding industrial area.
17.5.31. Three LCAs would experience indirect landscape effects, none of which are
considered significant.
Visual Effects (Year 1)
17.5.32. The completed Proposed Development is expected to result in direct visual
impacts within the 10km study area as the varied (over the construction period)
and relatively disruptive (in visual terms) visual impact of the Proposed
Development Site during construction is replaced with the organised layout of the
new buildings, stacks and associated infrastructure. Photomontages of the
Proposed Development of both the single-shaft and multi-shaft option at Year 1
have been produced and are shown in Figures 17-16 to 17-30 (Volume III). Their
locations have been established in consultation with SGC and BCC and are
illustrated in Figure 17-8 (Volume III).
17.5.33. Proposed external lighting during periods of operation after dark would also result
in direct visual impacts. An outline of the lighting principles for the Proposed
Development is provided in Chapter 4: Project Description. An outline lighting
strategy will be provided in the final ES.
17.5.34. Intermittent, visual effects would be likely to result from a plume emanating from
the stacks, which could form under certain atmospheric conditions, principally
when the steam / hot air from the stacks enters cold, still air, leading to
condensation and visibility as a white plume. This is normally an early morning /
late evening or winter phenomenon. The potential plume would be variable in
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extent and appearance or absent altogether. Further information is provided in
Chapter 11: Air Quality.
17.5.35. The likely effects on views within the 10km study area at Year 1 of operation are
provided in Appendix L Part 4, Volume II of this PEI Report. The main effects are
discussed below.
Close Views: up to 1km
17.5.36. The Proposed Development would be visible in views for users of the A403
(Receptors 9a and 9b). These would be interrupted by the buildings and
landscape of the existing Seabank 1 & 2 station and the Severnside Energy
Recovery Centre site (currently being developed). In addition, the tall HRSG
building and two stacks are proposed to be located to the southeast of the
Proposed Development Site at the furthest point from the A403. The buildings
and landscape of the Severnside Energy Recovery Centre site would assist in
reducing the perceived scale of the Proposed Development and screen low level
plant resulting in a Medium magnitude of change, which is considered a minor
adverse visual effect that is not significant.
17.5.37. Views for users of PROWs in Crook’s Marsh (Receptor 10a) would be more open
and direct with only small areas of scrub filtering views. Though woodland blocks
are to be planted as part of the Proposed Development along the southern
boundary, these would not have established sufficiently by Year 1 to reduce the
perceived scale of the structures within the Proposed Development Site or screen
low level plant. The Proposed Development would be seen however in the
context of other industrial developments on adjacent site as illustrated on Figures
17-22 (Volume III) and 17-24 (Volume III). The level of effect for Receptor 10a
would be High creating a moderate adverse visual effect, which is considered
significant.
Middle Distance Views: 1 to 5km
17.5.38. On completion, the Proposed Development would be seen as elements within the
panoramic views of the surrounds and the River Severn from the ridgeline to the
east. Users of the Community Forest Path on Spanorium Hill (Receptor 4a) would
see the Proposed Development located within the floodplain landscape of fields
and rhines and within the context of the other industrial developments within the
area as shown on Figure 17-17 and 17-19 (Volume III of this PEI). Planting along
the eastern boundary of the Proposed Development Site would not have
established by Year 1 of Operation to assist in reducing the perceived scale of
the Proposed Development or filter views of plant at low levels. The Medium
magnitude of change would result in a minor adverse visual effect which is not
significant.
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17.5.39. In contrast views from the north from Holloway Road (Receptors 2a and 2b) and
from Severn Beach (Receptors 11a and 11b) would be interrupted by buildings
and vegetation in the foreground as illustrated on Figures 17-27 and 17-29
(Volume III). Only the upper parts of the Proposed Development would be visible
above these foreground features. The top of the HRSG building, peaking plant
and the two stacks would be seen within the context of other tall structures within
adjacent sites including the recently constructed wind turbines and Seabank 1 &
2. The Low impact would result in a minor adverse or negligible visual effect
which is not significant.
17.5.40. To the southeast, development, landform and woodland would interrupt views of
the completed Proposed Development. Glimpsed views may be possible through
gaps in the ridgeline and woodland but for users of Blaise Castle public park
(Receptor 5a) and the Community Forest Path crossing the M5 (Receptor 3a)
they would experience no views of the Proposed Development.
Long Distance Views: 5 to 10km
17.5.41. Due to the nature of the topography on the edge of the Severn estuary there are
numerous potential long distance views towards the Proposed Development from
the west. These views are however, distant and interrupted by foreground and
middle ground features. They are also dependant on weather conditions. Only
the upper parts of the Proposed Development would be visible, seen within the
context of similar industrial developments with tall stacks, wind turbines and large
building blocks. Often the Proposed Development would be difficult to identify
within these views. As a result, the impact on all identified receptors experiencing
a view of the Proposed Development (Receptors 1a, 1b, 6a, 7a, 7b, 8a and 8b)
would be Low resulting in minor adverse or negligible visual effect, which are
not significant.
Visual Effects of Lighting
17.5.42. The lighting strategy will be carefully considered to minimise light spill and sky
glow resulting from the external and internal lighting of the Proposed
Development. Low intensity steady red aviation warning lighting and colour
markings are proposed to be positioned as close to the top of the stacks as
practicable. Though these would be visible in dark skies these would be seen
within the context of other lighting on tall stacks and wind turbines and
operational lighting in adjacent industries. As a result the visual impact on visual
receptors would be low resulting in a range of minor adverse to negligible
visual effects, which are not significant.
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Summary of Visual Effects on Completion (Year 1)
17.5.43. Upon completion of the Proposed Development, the relatively intrusive (in visual
terms) nature of the DCO Site during construction would be replaced with an
organised layout. Only users of PROWs on Crook’s Marsh (Receptor 10a) would
experience a moderate adverse significant adverse visual effect. The receptor is
within 1km of the DCO Site with open direct views. The Proposed Development
would be seen within the context of other industrial developments including the
recently constructed wind turbines and network of pylons and overhead power
lines.
17.5.44. All other identified visual receptors would experience minor adverse or negligible
visual effects, which are not significant.
Mitigation Measures
17.5.45. During construction all existing trees and shrubs to be retained (although this will
be limited) would be protected in accordance with BS 5837:2012 - Trees in
Relation to Design, Demolition and Construction. In addition:
• Suitable materials will be used, where possible, in the construction of
structures to reduce reflection and glare and to assist with breaking up the
massing of the buildings and structures; and
• Lighting required during the construction and operation stages of the
Proposed Development will be designed to reduce unnecessary light spill
outside of the site boundary.
Landscape Proposals
17.5.46. Landscape proposals are shown on Figure 17-15 (Volume III of this PEI). They
are intended to achieve the following objectives:
• To integrate the Proposed Development into the existing industrial
landscape of Severnside and the wider landscape character of Pilning
Levels;
• To break up the perceived scale of the buildings from nearby Public
Rights of Way and access roads;
• To create a wooded setting for the Proposed Development using native
species;
• To provide opportunities for habitat enhancement through natural
regeneration of ruderal vegetation; and
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• To encourage wetland habitats to develop adjacent to on-site water
attenuation features including swales, and a pond, and also off site beside
the Red Rhine.
17.5.47. To fulfil these objectives the landscape proposals are to:
• Establish substantial native species woodland blocks to the north and
south of the new power station;
• Retain and incorporate existing trees and shrubs into the woodland
blocks;
• Link woodland blocks through trees and shrub belts, to maintain
ecological connectivity;
• Define entrances into the Proposed Development through structural
planting;
• Develop suitable conditions to encourage large areas of ruderal
vegetation to grow, especially along the banks of the recently relocated
Red Rhine and swales along the southern boundary;
• Form new balancing pond with series of wetland and aquatic habitats,
interconnected with nearby swales and rhine network;
• Seek opportunities for series of informal amenity areas for employees
within the landscape framework; and
• Enhance the network of local footpaths and cycle ways through creation
of a multi-use public right of way. The new route would form an essential
link between existing and proposed routes to the south and north.
17.5.48. Once the final design is agreed, the landscape proposals would cover associated
development, such as pipelines, grid connections and access roads and access
points. The landscape proposals would seek to reinstate the existing landscape
to improve nature conservation and help absorb the Proposed Development into
the levels landscape.
Landscape Management and Maintenance Plan
17.5.49. A landscape management and maintenance plan will be produced following
receipt of the DCO as a Requirement to ensure the successful establishment of
new planting. The plan would set out management and maintenance procedures
for the following key elements of the landscape scheme:
• Woodland blocks;
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• Tree and shrub areas;
• Ruderal Vegetation;
• Wetland and aquatic habitats; and
• Grassland
17.5.50. Pedestrian and vehicular circulation areas would be finished in materials
appropriate to their use.
17.5.51. Lighting would be designed to minimise light pollution outside the operational
area both by appropriate selection of lighting installations to achieve minimum
lighting levels and switching arrangements to avoid unnecessary periods of
lighting. In addition, due to the proximity of the Proposed Development site to
Filton Airport, low intensity steady red aviation warning lighting and colour
markings would be positioned as close to the top of the stacks as practicable.
Summary of Mitigation
17.5.52. The soft landscape proposals, landscape management, hard landscape and
external lighting in addition to the form and materials of the buildings are a
response to the need to minimise potential adverse visual impacts and to
enhance the character of the landscape. The proposals follow mitigation advice in
EN-1 which encourages the reduction in scale of the buildings through
appropriate siting, design including colours and materials, and landscape scheme
to mitigate adverse landscape and visual impacts.
17.5.53. Planting of woodland blocks and trees and shrubs takes account of NPS-EN2
and with the aim of filtering views of the Proposed Development, visually
enclosing the DCO Site from Crook’s Marsh at a low level thereby reducing the
scale of the Proposed Development. Landscape management is proposed to
ensure the long term survival of proposed planting. External lighting design will
take account of NPPF paragraph 125 and limits the impact of artificial light
pollution on local amenity and nature conservation.
17.5.54. The predicted effects in Year 15, taking into account these mitigation measures,
are discussed below.
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17.6. Residual Effects and Conclusions
Landscape Effects (Year 15)
17.6.1. The residual effects on landscape character of the Proposed Development after
15 years of operation are described in Appendix L Part 3, Volume II of this PEI
Report. The main aspects are summarised below.
Operation: Direct Landscape Effects (Year 15)
17.6.2. By Year 15 mitigation planting would have established sufficiently to enclose the
Proposed Development Site and provide structure to the Proposed Development
allowing it to integrate into the industrial landscape of the Levels. Though the
magnitude of change on the immediate landscape of the Proposed Development
Site is Medium, within the context of LCA 1 it is Low. The resulting negligible
effect is not significant.
Operation: Indirect Landscape Effects (Year 15)
17.6.3. Establishment of woodland blocks in the north and south of the Proposed
Development Site would assist in screening and softening views within and
around the Site, reducing intervisibility with adjacent LCAs. Careful design of the
form for buildings and hard landscape materials would help the Proposed
Development to be incorporated into the landscape of the existing industrial area.
17.6.4. LCA2 Severn Ridges, to the east has a High sensitivity to change and even with
established mitigation planting the Proposed Development would continue to
cause a Low magnitude of change resulting in a minor adverse indirect
landscape effect which is not considered significant.
17.6.5. LCA 5 Hallen Marsh and LCA 6 Avonmouth to the south are also expected to
continue to experience a Low magnitude of change. Though the Proposed
Development would be visible from the northern part of both LCAs, buildings and
vegetation within the LCAs and within the Proposed Development would limit
intervisibilty. The negligible landscape effects are considered not significant.
17.6.6. All other identified LCAs within the 5km study area have no intervisibility and
would experience no landscape effects, hence is of negligible significance.
Summary of Landscape Effects (Year 15)
17.6.7. The growth of the trees and shrubs planted as part of the Proposed Development
would help to absorb the Proposed Development into the landscape by year 15.
Only one LCA would experience an indirect minor effect. All other LCAs
experience negligible landscape effects, none of which are significant.
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Visual Effects (Year 15)
17.6.8. The residual effects on views of the Proposed Development after 15 years of
operation are described in Appendix L Part 4, Volume II of this PEI Report. The
main aspects are summarised below.
17.6.9. The woodland blocks to the north and south of the Proposed Development Site
and planting around the balancing pond to the east would have matured
sufficiently to help reduce the scale of the Proposed Development and screen low
level plant. Habitat enhancement works to encourage ruderal vegetation,
especially along the relocated Red Rhine would have encouraged biodiversity
and protected an important habitat of the Levels.
17.6.10. Users of the PROWs on Crook’s Marsh (Receptor 10a) would experience filtered
and screened views of low level buildings and plant within the Proposed
Development. Tall structures would be visible above the woodland blocks, which
would help to reduce the scale of these structures within the views, as illustrated
in Figure 17-23 and 17-25 (Volume III of this PEI). The Medium magnitude of
change would result in a minor adverse visual effect at this location, which is not
considered significant.
17.6.11. Planting of woodland blocks in the northwest of the Proposed Development Site
would further filter views from the A403 (Receptors 9a and 9b) and from Severn
Beach (Receptors 11a and 11b), screening low level structures and helping to
reduce the scale of the proposed structures, as illustrated in Figures 17-28 and
17-30 (Volume III of this PEI). The resulting Low magnitude of change would
result in either a minor adverse or negligible visual effect, which is not
significant.
17.6.12. From elevated locations to the east, planting along the southern and eastern
boundary of the Proposed Development Site would help to reduce the perceived
scale of the Proposed Development and filter views of plant at low levels, as
shown in Figures 17-18 (Volume III of this PEI) and 17-20 (Volume III). The Low
visual impact would result in a negligible visual effect, which is not significant.
Summary of Visual Effects (Year 15)
17.6.13. By Year 15 of operation, the Proposed Development would cause no significant
visual effects.
Decommissioning Phase
17.6.14. It is envisaged that the plant would have a design life of 30 years, with an
operating life possibly beyond this. It is not possible to accurately predict the
baseline conditions at this point in the future, however it is anticipated that the
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area would include the cumulative schemes outlined below, which are broadly
industrial in nature. It is also expected that decommissioning would be relatively
short in comparison to the construction period and therefore only a short-term,
temporary effect, which is likely to be similar in nature and type of effects as the
construction phase.
The decommissioning of the plant has the potential to reverse any effects
identified on the LCAs and visual amenity and would therefore have the potential
to lead to a minor, but not significant beneficial effect on these parameters.
Conclusion
17.6.15. The Proposed Development is industrial within an area surrounded by industrial
development.
17.6.16. National and District Landscape Character Assessments locate the DCO Site
within an area punctuated by large industry and recognise the landscape
character within the 5km study area is influenced by industrial works and
distributor sheds on the Levels.
17.6.17. The Proposed Development maintains the industrial character of the immediate
landscape of the DCO Site adjacent to Seabank 1 & 2 to the west, the
Severnside Energy Recovery Centre currently under construction to the
northwest, the derelict site of the former ICI / Terra Nitrogen works to the north
and the proposed large warehouses of Central Park to the northeast. The
introduction of new industrial structures into views already dominated by industry
is considered appropriate.
17.6.18. Tree and shrub planting along the southern and northern boundary would create
a new landscape framework and maintain continuity with established landscape
areas within Seabank 1 & 2 and the Western Approach Distribution Centre Phase
1. In addition, these would link to proposed landscape areas within the
Severnside Energy Recovery Centre, forming a substantial area of trees and
shrubs within the landscape.
17.6.19. All direct and indirect landscape effects identified during construction and
operation are considered not significant. The existing mixed industrial and
agricultural character of the surrounding area would be maintained and enhanced
through an appropriate industrial development. All intervisibilty of the Proposed
Development and adjacent LCAs is within the context of the existing industries.
The registered Parks and Gardens are to the south east and would experience
no intervisibility with the Proposed Development and the LCA.
17.6.20. Of the visual receptors with close range views, their views are often interrupted
by pockets of scrub and are seen within the context of adjacent industrial
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development and construction sites. Away from the DCO Site, middle distance
views are experienced over the top of existing vegetation and buildings with only
the top of industrial structures visible on the skyline.
17.6.21. Distant views are usually panoramic along the Severn estuary, where the DCO
Site is seen as a small part of an expansive panorama. Clarity of these views are
dependent on weather conditions and are interrupted by structures and
vegetation in the foreground and middle ground. Often it is only the tall elements
of industrial developments which are visible in the distance with the ridgeline to
the east forming the horizon.
17.6.22. During construction there would be one significant adverse visual effect for users
of PROWs on Crook’s Marsh (Receptor 10a) with close range views of the DCO
Site. Though patches of scrub may interrupt views, the disruption resulting from
construction would result in visual intrusion. This intrusion would be seen within
the context of the industrial development on the Site and surrounds, wind
turbines and the networks of pylons carrying overhead power lines passing
through the area.
17.6.23. As the Proposed Development reaches its completed height and mass, users of
PROWs on Crook’s Marsh (Receptor 10a) would continue to experience
significant adverse effects. The woodland blocks planted along the southern
boundary would not have established by Year 1 of operation to filter views.
17.6.24. Growth of the woodland blocks and other planting after 15 Years of operation
would help to reduce the perceived scale of the Proposed Development and
screen low level plant for users of the PROWs on Crook’s Marsh (Receptor 10a)
resulting in a Minor adverse visual effect which is not considered significant. All
other visual receptors would experience neutral or not significant effects.
17.6.25. The Proposed Development would introduce a new power station into an existing
industrial area. The operation of the Proposed Development would cause limited
significant visual effects with the introduction of a new visual landmark that is
carefully designed to add interest to existing industrial views. The industrial
nature of the Proposed Development is in character with the surrounding
industrial landscape of the Levels and the Severn estuary.
17.7. Cumulative Effects Assessment
17.7.1. The Severnside and Avonmouth area is subject to a number of development
proposals, as discussed in Chapter 7: Assessment Methodology. It is important to
consider the potential for cumulative effects of the Proposed Development and
associated infrastructure with these other developments planned or consented in
the vicinity of the DCO Site. The schemes included within the cumulative effect
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assessment have been identified in consultation with SGC and BCC. Existing
schemes such as Seabank 1 & 2 form part of the baseline conditions are and are
therefore not assessed here.
17.7.2. Of most relevance to the assessment of effects on landscape character and
visual amenity within a 3km radius of the DCO Site are the following:
• Avon Power Station (not consented);
• Severnside Energy Recovery Centre (currently under construction);
• Bottom Ash Facility – SITA;
• The proposed Spine Access Road (currently under construction);
• Bristol Resource Recovery Centre - SITA/Cyclamax;
• Biofuel Renewable Energy Plan on former Columbian Chemicals;
• Rockingham Park;
• Virador Resource Recovery Centre;
• Anaerobic Digestion Facility – New Earth Solutions; and
• Central Park.
17.7.3. Immediately to the northwest of the Proposed Development Site are the
proposed Severnside Energy Recovery Centre (SERC), the Spine Access Road
and the Bottom Ash Facility. Construction started on SERC in winter 2013/2014
and consists of a number of buildings including a 126m AOD stack located in the
southeast of the SERC site, close the Proposed Development Site boundary.
Balancing ponds and areas of trees and shrubs are proposed in the northwest of
the SERC site adjacent to the A403. Indicative 3D visualisations of the Proposed
Development with the SERC development are illustrated in Figure 4-6. The
grouping of buildings adjacent to the Proposed Development Site allows
development to be located together within the landscape separated by the Spine
Access Road, realigned Red Rhine and woodland blocks. Views from the A403
are filtered through the proposed landscape area along the road to the SERC
structures. The Spine Access Road will serve the Proposed Development, SERC,
and the Bottom Ash Facility and will separate these developments from Seabank
1 & 2 to the south. The grouping of development with landscape treatment
around helps to absorb the developments into the landscape and filter views from
nearby public vantage point. More distant views would see the tall elements of
the developments grouped together in a similar fashion to other developments
along the skyline in Avonmouth. Together it reduces the potential visual impact.
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17.7.4. To the north of the Proposed Development Site is the proposed Avon Power
Station. This is at an early stage of planning (not consented) and is located on
the former ICI / Terra Nitrogen site, immediately north of the Proposed
Development Site. Currently there is little information regarding the design of the
scheme but the principle of grouping development and creating landscape
frameworks would help to minimise landscape and visual effects.
17.7.5. To the northeast of the Proposed Development Site is an area identified for
development of Central Park. The proposed 600 acre warehouse and distribution
park is designed to be the South West’s largest distribution park. Currently the
road infrastructure has been constructed and the area cleared for development
and undergoing land raising. Assuming the development would be similar in style
to Western Approach Distribution Park Phase 1, it would consist of large
warehouses within a landscape framework of grass verges, rhines and tree and
shrub planting along the major access routes. The development would gradually
enclose the Proposed Development Site to the north. Together the developments
would increase development within the Levels landscape but by following the
principle of grouping development and setting it within a landscape framework,
landscape features can be protected minimising landscape and visual impacts.
17.7.6. Away from the immediate boundaries of the Proposed Development Site within
the landscape to the south three developments are proposed, as discussed
below.
17.7.7. An Anaerobic Digestion Facility would be constructed to the south of the
Avonmouth LNG Storage Facility, approximately 600m southeast of the Proposed
Development Site. The development would be located away from the DCO Site
but would further industrialise Crook’s Marsh and Hallen Marsh to the south.
Users of PROWs moving through these areas would experience views of the
Anaerobic Digestion Facility with the backdrop of the LNG facility. The Proposed
Development would be in the middle distance as part of an industrial view of
Seabank 1 & 2 and the Severnside Energy Recovery Centre.
17.7.8. The Resource Recovery Centre being developed by Viridor and the Selvaco Bio-
fuel energy plant would both be located on existing industrial sites to the south of
the Proposed Development Site. These developments would be seen as part of
the industrial built up area of Avonmouth. Indicative 3D visualisations of the
Proposed Development with the Resource Recovery Centre are illustrated in
Figure 4-6, Volume III of this PEI Report.
17.7.9. Two further developments are proposed within Avonmouth, over 2km from the
Proposed Development Site. Rockingham Park, an industrial redevelopment and
Bristol Resource Recovery Centre would again be located on existing industrial
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sites to the south of the DCO Site. Again, the developments would be viewed as
part of the industrial built up area of Avonmouth.
17.7.10. Cumulative developments in the vicinity of the DCO Site are all industrial and
would maintain the characteristic industrial landscape of the southern part of LCA
1 resulting in Low landscape magnitude of change and a negligible cumulative
effect by Year 15 of operation of the Proposed Development, which is not
significant. Careful grouping of built structures within a strong wooded framework,
interspersed with rhines helps to minimise both landscape and visual effects. Tall
elements of industrial developments would be seen together, providing vertical
context and minimising visual intrusion into views from identified visual receptors
resulting in Low visual impact and minor adverse to negligible cumulative visual
effects by Year 15 of operation of the Proposed Development, which are not
significant.
17.7.11. Chapter 7: Assessment Methodology explains that there is no requirement to
assess the cumulative effects of the CCS. This would form a separate DCO
Application and would be judged on its own merits, if and when it is required by
the UK Government and the technology exists. Generally speaking however, it is
considered that a future CCS development would be in line with the SGC Core
Strategy and is unlikely to cause a significant change to the landscape or visual
amenity of the area once the other cumulative schemes and the Proposed
Development have been built and implemented.
17.8. Impacts and Effects yet to be Determined
17.8.1. There are no impacts and effects yet to be determined, however, the scheme
design may be subject to change prior to submission of the final DCO application.
Any changes that lead to differing or new impacts and effects will be highlighted
within the final ES, along with the reasons for the change.
17.8.2. It is also possible that the baseline conditions will change between the
preparation of this PEI Report and the final ES; landscape conditions are
dynamic and evolve over time. The Proposed Development Site is currently
subject to excavation, top soil stripping, and levelling in certain areas in order for
third parties to deliver the Spine Access Road and new channel for the Red
Rhine, which are discussed in Chapter 2: The DCO and EIA Process and
Chapter 7: Assessment Methodology. A haul road is also being constructed
through the middle of the Proposed Development Site to enable access by third
party from the roundabout to the east of the Site to the Severnside Energy
Recovery Centre to the west. These works onsite are being undertaken by other
developers, under extant planning permissions and are separate to the Proposed
Development.
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17.8.3. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changes
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
17.8.4. Photographs used in this PEI Report were taken in early spring 2013 and will be
updated in the final ES.
17.8.5. The assessment of effects relies on field data collected during autumn 2012 and
winter 2013. Field surveys recorded existing baseline data and assessed the
likely impacts of the Proposed Development on the landscape character within a
5km radius of the DCO Site and for visual receptors within a 10km radius of the
DCO Site. This data may also need to be revisited in light of the evolving nature
of the Proposed Development Site and surrounds, due to the construction of the
SERC and Central Park in particular.
17.9. References
Ref 17-1 Landscape Institute and Institute of Environmental Management and
Assessment (2013) Guidelines for Landscape and Visual Impact
Assessment 3rd Edition
Ref 17-2 Countryside Agency and Scottish Natural Heritage (2002) Landscape
Character Assessment: Guidance for England and Scotland
Ref 17-3 Landscape Institute (2011) Landscape Institute Advice Note 01/11:
Photography and photomontage in landscape and visual impact
assessment
Ref 17-4 Planning Inspectorate (2012) Using the 'Rochdale envelope' Version
2
Ref 17-5 Natural England (2012) NCA Profile: 106 Severn and Avon Vales
(NE336)
Ref 17-6 Natural England (2013) NCA Profile: 118 Bristol, Avon Valleys and
Ridges (NE 400)
Ref 17-7 South Gloucestershire Council (2005) South Gloucestershire
Landscape Character Assessment
Ref 17-8 South Gloucestershire Council (2014) South Gloucestershire
Landscape Character Assessment – Draft Review
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18. SUSTAINABILITY AND CLIMATE CHANGE
18.1 Introduction
18.1.1. This chapter of the PEI Report addresses the potential wider sustainability impacts predicted to arise as a consequence of the Proposed Development, and outlines the measures that will be considered to improve sustainability within its design and management. The Associated Development infrastructure has not been assessed within this chapter as it is considered to have an insignificant effect on climate change and has an imperceptible contribution to sustainability.
18.1.2. Through consideration of national, regional and local policy guidance promoting sustainability principles, this assessment aims to address the effects (and where appropriate propose mitigation measures) of the Proposed Development through the following key sustainability themes:
• Natural resource efficiency (land, materials, energy and water);
• Waste minimisation;
• Sustainability of the fuel stock;
• Climate change mitigation and adaptation; and
• Biodiversity and ecology.
18.1.3. It should be noted that many of the sustainability issues are also discussed elsewhere in this PEI Report. Due to overlap between subject areas and relevant chapters, these are referenced where appropriate.
18.1.4. This chapter is also supported by a Carbon Impact Assessment of the Proposed Development, contained within Appendix M, Volume II of this PEI Report. Whilst the detailed methodology is contained in this Appendix, the results are summarised in this chapter. The calculation of the carbon footprint reported in this chapter is based on the current design stage of the Proposed Development, and therefore may be subject to change going forward. Any changes will be set out and explained in the final ES, along with the final assessment conclusions.
Legislation and Planning Policy Context
18.1.5. Appendix D, Volume II of this PEI Report presents a summary of the planning policy relevant to this chapter.
18.2 Assessment Methodology and Significance Criteria
18.2.1. There is no standard methodology for assessing the magnitude of sustainability impacts and significance of sustainability effects of NSIPs, and each project is
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evaluated according to its individual characteristics. The approach taken for the Proposed Development is to qualitatively consider it against the key sustainability themes outlined above and the measures taken to incorporate and improve sustainability within the design and management are then outlined. This approach is considered to be appropriate for the likely types of impact that may result from the Proposed Development.
18.2.2. A Sustainability Assessment provides a mechanism for considering the sustainability of the project as a whole and for enhancing the benefits generated by such a project through integrating sustainability considerations throughout the lifecycle of the development. It summarises the features and attributes of the Proposed Development that will contribute to or affect each of the sustainability themes, and sets out actions which could be taken during the design, construction and operation that would further assist in delivering sustainability benefits for the local and wider area.
18.3 Baseline Conditions
18.3.1. This chapter summarises the findings of a number of other assessments within the PEI Report. Baseline information can be found in the relevant chapters referenced throughout this assessment and a description of the existing Proposed Development Site is provided in Chapter 3: The Site and Its Surroundings of this PEI Report.
18.4 Development Design and Impact Avoidance
18.4.1. The project design has taken into account a number of sustainability features, such as the selection of CCGT technology with good thermal efficiency in line with BAT, provision of sufficient water attenuation to maintain greenfield run off rates following construction of the Proposed Development, and securing a biodiversity and landscaping area. These design measures (in addition to a number of others) are discussed in more detail below.
18.5 Potential Effects and Mitigation Measures
Natural Resource Efficiency
Reducing the use of natural resources in construction materials
18.5.1. The selection of materials for the construction of the Proposed Development has been informed by sustainability principles, including the prudent and efficient use of natural resources and the use of re-used and recycled materials. A primary example of sustainable procurement is to question the need/requirement for the commodity in question.
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18.5.2. To minimise the use of natural resources and unnecessary materials procured for the Proposed Development, a number of services and existing infrastructure including access roads, cooling water return pipeline, gas supply pipeline and grid connection will be shared with the existing Seabank 1 & 2 generating station. Sourcing of materials will be considered once the detailed design has been confirmed.
18.5.3. A Decommissioning Plan will be produced and agreed with the EA as part of the Environmental Permitting process for the generating station. At the end of the Proposed Development’s expected operating life, all residues and operating chemicals would be cleaned out from the plant and disposed of in an appropriate manner, with the plant and all equipment removed from the Proposed Development Site.
Minimising use of Greenfield land
18.5.4. It is not intended to remove significant quantities of material from Site during construction; the land is not currently occupied by buildings and therefore no demolition is required. Topsoil removed prior to land raising would be stockpiled and retained for landscaping. The landscape proposals for the Site are to maximise the landscape ecological value through planting of native species.
Minimising use of Water
18.5.5. Water is required for a number of purposes within the generating station such as cooling, boiler feed, domestic, emergency fire water and for boiler acid washes during commissioning. The cooling process will use treated waste water from the WWTW (as currently used by Seabank 1 & 2). This cooling system is required to condense the steam used in the power generation process once it has been exhausted through the steam turbine, and before it is returned to the boiler for re-use. Hybrid-cooling technology is the method of cooling that represents BAT for the Proposed Development. In addition to re-utilising waste water, by using a bank of low height hybrid cooling cells, the volume of water being used is less than compared to direct water cooling.
18.5.6. Other water efficiency measures will be adopted where possible to reduce the effect on the water supply network. These include:
• Selection and specification of water efficient equipment to reduce the amount of water required;
• Implementation of staff-based initiatives such as turning off taps, plant and equipment when not in use both on-site and within site offices; and
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• Use of recycling water systems such as wheel washes, site toilets, hand washing.
18.5.7. Water consumption will be monitored through process and administration areas to identify opportunities for water usage reduction and leak detection.
Maximising Energy Efficiency
18.5.8. The design of the Proposed Development is based on the principles of BAT as outlined in the European Reference document on Best Available Techniques for Large Combustion Plants (“Best Available Technique reference ‘BREF Notes’”). The CCGT will operate at an anticipated efficiency of around 58% which compares favourably with indicative BAT efficiencies for equivalent power generation from natural gas (54-58% for new plants, 50-54% for existing plants) and is considerably higher than that for conventional coal, oil or gas fired steam turbine generating plants.
18.5.9. The peaking plant will either be OCGT or reciprocating engine technology. OCGT units are slightly less efficient than reciprocating engines (41% efficient for OCGTs, compared to 45% for a reciprocating engine) and so OCGTs have been used in modelling the carbon emissions from the Proposed Development as a ‘worst-case’ scenario from a climate change impact assessment perspective.
18.5.10. The peaking plant avoids having to operate the CCGTs at low loads to cover short-term peaks in electricity demand, which would be less efficient than purpose built peaking plant.
18.5.11. The modern plant design follows current best practices in optimising efficiency and the use of CCGT technology is recognised as indicative BAT for power generation from natural gas (with reference to the BREF Note) by capturing heat remaining in the gas turbine exhaust, and creating steam to generate additional electricity via a steam turbine.
18.5.12. There are numerous design elements which will contribute to achieving this efficiency including:
• Automated process control to optimise combustion conditions and performance;
• Plant components will be sized appropriately for the design capacity of the plant;
• Where possible, variable speed drives will be included on all sizeable motors (such as cooling water pumps and fans); and
• Insulation of heated surfaces and minimisation of pipe runs.
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18.5.13. Regular planned maintenance will also be conducted to optimise the efficiency of the equipment.
18.5.14. The Applicant is focused on generating electricity as efficiently as possible and maximising exported power. Therefore several Key Performance Indicators (KPIs) regarding energy efficiency will be monitored regularly and tracked during plant operation, including the MWe exported per kWh of natural gas consumed and the parasitic load (i.e. the difference between gross and net power output), with a small increase in the parasitic load triggering the need for further evaluation .
18.5.15. The Applicant is strongly committed to providing energy in a reliable and sustainable way and a key priority is a significant and continuing reduction in the carbon intensity of the electricity produced by its generation fleet. This is defined in the Applicant’s corporate goal to reduce the carbon intensity of electricity generated by 50% by 2020 (against a 2006 baseline). This goal will be achieved through a diverse range of solutions including:
• The commissioning and development of additional renewable energy capacity within the company portfolio;
• Lower emissions from more efficient and flexible gas-fired generation;
• Delivering innovative solid fuel solutions at coal-fired stations; and
• Reduced output from coal-fired stations as they use up their allocated running hours under the EU’s Industrial Emissions Directive.
18.5.16. The Applicant has also successfully completed the Certified Emissions Management and Reduction Scheme (CEMARS) and encouraged eighty six of its main suppliers to sign up to the programme (Ref. 17-2).
Waste Minimisation
18.5.17. The Applicant endorses the waste hierarchy, where the first priority is to prevent waste, second priority is to reuse and the last resort being disposal.
18.5.18. The CEMP will be produced prior to construction of the Proposed Development and will set out how waste will be managed on site, and opportunities to recycle waste will be explored. A framework for the CEMP is presented in Appendix C, Volume II of this PEI Report. Additionally a Decommissioning Plan will be produced as outlined above, with all residues and operating chemicals cleaned out from the plant and disposed of in an appropriate manner at the end of the Plant’s operating life.
18.5.19. Some waste will be generated during the construction programme including packaging and liquid wastes such as oils and chemicals. During the construction
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phase, waste management requirements will be communicated to all contractors and sub-contractors to ensure waste is managed in accordance with the waste hierarchy and relevant statutory controls. These measures will be controlled through the CEMP.
18.5.20. There is not expected to be significant waste associated with the operational phase of the Proposed Development. Those that are generated will be managed and treated in line with the waste hierarchy and recycled where possible, or otherwise disposed of through an appropriately licensed waste contractor.
Sustainability of the Fuel Stock
18.5.21. Natural gas will be used as the primary fuel source for the turbines, supplied from the National Grid Transmission network. Two high pressure natural gas feeds supply the current Seabank 1 & 2 generation station and these will be used to supply the gas to the Generation Station Site.
18.5.22. National Grid has undertaken a feasibility assessment and does not expect that significant infrastructure upgrades will be required to deliver the necessary gas to the Proposed Development.
Climate Change
18.5.23. The design, construction and operation of the Proposed Development will seek to mitigate the causes of climate change by contributing to reducing greenhouse gas emissions from UK electricity generation and adapting to the predicted impacts of climate change, as discussed below.
Mitigation: Carbon Footprint Assessment 18.5.24. A preliminary carbon impact assessment has been undertaken for the Proposed
Development using the Greenhouse Gas Protocol (Ref: 16-3) as a basis. The Protocol provides a methodology for calculating the carbon footprint of a project and was developed by the World Resources Institute and the World Business Council for Sustainable Development.
18.5.25. Where possible, design values for the Proposed Development have been used, however some assumptions have been made where data is not yet available or where exact values are not known; these assumptions are detailed in Appendix M, Volume II of this PEI Report. Any changes to these assumptions between preparation of this report and submission of the DCO application will be highlighted in the final ES and the assumptions on which the final assessment is based will be clearly stated. It is not currently anticipated that any such changes would substantially change the outcome of this preliminary assessment.
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18.5.26. The Greenhouse Gas Protocol defines different sources of GHG emissions into a series of categories or ‘scopes’. These definitions have been used in this assessment to determine the scope and sources of emissions to be considered and the relevant aspects to the Proposed Development are as follows:
• Scope 1: Direct Emissions
o Fossil Fuel combustion on site: Natural Gas and Distillate (for black starts only);
• Scope 2: Electricity Indirect Emissions
o Not applicable. The parasitic load of the plant will be sourced from the electricity generated on site therefore there are not expected to be any Scope 2 emissions;
• Scope 3: Other Indirect Emissions
o Transport of raw materials to site;
o Transport of waste materials from the site;
o Transport of distillate to site has been scoped out, as it will only be required for a black start event which is considered to be abnormal and not required in significant volumes.
18.5.27. Table 17-1 below summarises the total annual operational carbon footprint of the Proposed Development, based on the preliminary assessment. This is calculated at 1,161,353 tonnes CO2 equivalent (tCO2e) based on current assumptions.
Table 17-1: Total Footprint Emissions Element of Footprint tonnes CO2e Scope
Natural Gas combustion 1,161,301 Scope 1 Electricity consumption N/a Scope 2 Natural Gas Transport N/a Scope 3 Raw materials transport 49 Scope 3 Waste transport 2 Scope 3
TOTAL annual carbon emissions 1,161,353
18.5.28. Considering Scope 1 emissions only, and based on currently available information, the carbon intensity of the Proposed Development is approximately 331tCO2/GWh during operation and assuming full load. This compares favourably to the carbon intensity of both the average UK power station (using all fuel types including nuclear and renewable) and an average UK natural gas fired power station, which have carbon intensities of 483tCO2/GWh and 415tCO2/GWh
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respectively (Ref. 17-4). Therefore the Proposed Development represents annual carbon savings of between 84 and 152 tonnes of CO2 on a per GWh basis compared to UK average power stations for the generation of electricity alone. Bearing in mind that the Proposed Development is replacing coal fired power station that are being shut down under the requirements of the Large Combustion Plant Directive, which are more carbon intensify than the UK average power station, this calculated figure is considered robust and possibly an underestimate of the annual carbon savings.
18.5.29. Note these indicative carbon savings include the emissions associated with the Scope 1 emissions only, but the additional of Scope 3 emissions will make a negligible difference to these calculations. As indicated in Table 17-1 above, the majority of emissions will originate from the combustion of the fuel. This remains the case even when sensitivity tests were carried out to double the distance the raw materials and waste were hypothetically transported (from 80km to 160km), with an increase of less than 0.1% to the overall footprint.
18.5.30. It is recognised that technological progress and developments in the regulatory framework for the use of carbon capture technology are likely to occur within the lifetime of the Proposed Development. Therefore, in accordance with UK CCR requirements, the Proposed Development will incorporate an area set aside for the potential future installation of Carbon Capture technology, and the design of the new power station will be developed with consideration for the possible future retrofitting of carbon capture technology at some future date. A CCR report will be submitted in support of the DCO application. Should carbon capture be installed in the future, approximately 90% of the carbon emissions from the Proposed Development would be compressed and captured.
Transport
18.5.31. A detailed Transport Assessment is considered in Chapter 10: Traffic and Transport. Transport during the operational phase has been excluded from the scope of that assessment as agreed with SGC, BCC and the HA, given the difference in traffic volumes associated with each phase.
18.5.32. A Travel Plan will be prepared for the construction phase of the Proposed Development. The implementation of measures within the prepared travel plan will seek to reduce the number of vehicles travelling to and from the site during construction. Measures within the Travel Plan will include encouraging journeys by public transport through the provision of shuttle bus services at public transport interchanges, introduction of a car sharing scheme to reduce single occupancy car journeys and other measures to promote cycling and walking.
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18.5.33. Opportunities to transport materials for the enabling works by rail and via the Avonmouth Port will be explored and discussed with the appropriate authorities and chosen contractor, although at this stage of the project it has been conservatively assumed all trips would be via road. Additionally, the impact on the highway network will be reduced through implementing measures such as limiting the number of deliveries during peak hours and stockpiling material to avoid deliveries during holiday periods. Distances travelled will be reduced where feasible through for example the use of material sourced from local quarries and of construction materials sourced from local suppliers in the Avonmouth/ Severnside area.
18.5.34. There will be no vehicle movements associated with the delivery of primary fuel (natural gas) to the Proposed Development as this will be supplied directly from the National Grid Transmission Network. Traffic movements during the operational phase will be restricted to staff travel, delivery of auxiliary materials and back-up distillate fuel and transport of waste from the Site.
18.5.35. The preliminary carbon assessment of the Proposed Development (Technical Appendix M, Volume II) encompasses carbon emissions arising from the transport of auxiliary raw materials to the Site as well as waste arising from the Proposed Development. It demonstrates the relatively small contribution of carbon emissions associated with the transport within the overall annual carbon footprint, even when a worst-case scenario is considered and the distances travelled are hypothetically doubled.
Climate Change Adaptation
18.5.36. In addition to any potential impacts the Proposed Development may have on climate change, there is the potential for climate change to impact on the design and operation of the Proposed Development. Such climatic impacts may include increased incidences of heavy and prolonged rainfall which could increase flood risk from surface water, groundwater and drainage systems. As such, adaptation to climate change concerns how the Proposed Development avoids or reduces its exposure to the effects of future climate change such as increased temperatures and flood risk.
18.5.37. The management of risk from climate related events has been considered by the Applicant for a considerable period of time. The Applicant has prepared a Climate Adaptation Report (June 2011) (Ref. 17-5) and has prepared for such eventualities within its Asset Management System, for example through enhancing its ability to respond to the extreme weather events more likely with climate change.
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18.5.38. A full FRA will be provided with the DCO Application and the findings included in the final ES. Chapter 14: Flood Risk, Hydrology and Water Resources summarises the FRA which is provided in Appendix J, Volume II of this PEI Report.
18.5.39. The outputs of the UK Climate Projections (UKCP09) climate change scenarios indicate a shift towards wetter winters over the whole of England by as much as 20% by the 2050s. The UKCP09 climate projections have been included in the Flood Risk Assessment.
18.5.40. Without action, there would be potentially high risk of flooding on the Proposed Development Site from fluvial and tidal sources. To mitigate this risk, the FRA proposes raising the finished floor levels of the Generating Station Site to up to 8.31m AOD in order to protect against extreme flooding and taking into account climate change allowance; the DCO Application includes additional contingency and allows the finished ground levels to be raised up to 8.5m AOD. The FRA indicates that during the ‘future baseline’ scenario, land raised within the Generation Station Site boundary will not be flooded for all fluvial scenarios, including 1 in 1000 years (inclusive of climate change) events and all tidal scenarios (including breach events) up to 1 in 200 years (inclusive of climate change) events. On completion of the Proposed Development, surface water runoff will be restricted to pre-development rates using Sustainable Urban Drainage System (SuDS) techniques. The FRA includes a commitment to include a surface water pond(s) up to 3,800m3 capacity based on the maximum built area for the Proposed Development.
18.5.41. As discussed previously the Proposed Development also incorporates a number of measures to conserve water during operation. This will increase the Proposed Development’s resilience to future temperature rises and potential droughts as a result of climate change.
Biodiversity / Ecology
18.5.42. Chapter 16: Ecology of this PEI Report considers in detail the potential effects and associated ecological effects of the Proposed Development on landscape and wildlife. Surveys have shown that the current site represents a mix of habitats currently, mainly grassland, shrub and watercourses / wetland.
18.5.43. Potential adverse ecological impacts resulting from the construction and operation of the Proposed Development could result from the loss of habitats, direct and indirect disturbance to species, changes to surface water drainage, potential pollution events during construction, lighting effects and air quality changes. Effective mitigation measures have been incorporated into the design of the Proposed Development to address these likely impacts. These are
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PEI Report – Chapter 18 Sustainability and Climate Change
summarised in Chapter 16 Ecology and include the creation of areas of habitat suitable for reptiles; maintaining strips of rough, tussocky grassland alongside hedgerows and rhines; and the incorporation of green roofs and brown roofs on some of the lower structures to provide suitable habitat for terrestrial invertebrates.
18.6 Residual Effects
18.6.1. Several characteristics are incorporated into the design, construction and management of the Proposed Development which meet the key sustainability requirements of sustainable design and efficient, sustainable use of land, material and resources, as set out in national, regional and local policy.
18.6.2. Through the design, construction and operation of the Proposed Development, the Applicant seeks to mitigate the causes of climate change by contributing to reducing greenhouse gas emissions associated with UK electricity generation and adapting to the predicted impacts of climate change. It will provide a lower carbon source of electricity than the UK average, with the carbon assessment demonstrating that the Proposed Development will outperform the UK average fleet of existing power stations within the UK on a tonnes CO2 per GWh basis.
18.6.3. The Proposed Development will incorporate a number of design and operational measures to increase resilience to potential effects of climate change including the mitigation of potential flood risk.
18.7 Cumulative Effects Assessment
18.7.1. This section assesses the effect of the Proposed Development in combination with other developments in the area that have been identified in Chapter 7: Assessment Methodology (section 7.4).
18.7.2. It is not considered that the other developments in the area have the potential to lead to cumulative sustainability effects when considered with the Proposed Development.
18.8. Impacts and Effects yet to be Determined
18.8.1. The calculation of the carbon footprint reported in this assessment is based in the current design stage of the Proposed Development, and therefore may be subject to change as further design work is undertaken. Any changes will be set out and explained in the final ES, along with the final assessment conclusions.
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18.9. References
Ref. 17-1 Biodiversity 2020: a Strategy for England’s Wildlife and Ecosystem Services (Defra) August 2011
Ref. 17-2 SSE plc Annual Report 2013
Ref. 17-3 GHG Protocol for Project Accounting’ World Resources Institute and the World Business Council for Sustainable Development (2005).
Ref. 17-4 Electricity: chapter 5, Digest of United Kingdom energy statistics (DUKES). Published by the Department of Energy & Climate Change (DECC), July 2013. Available online: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/65818/DUKES_2013_Chapter_5.pdf (last accessed 12th November 2013)
Ref. 17-5 SSE Power Distribution. Climate Change Adaptation Report. Appended Version 3.1, June 2011. Available online: http://archive.defra.gov.uk/environment/climate/documents/adapt-reports/04distribute-trans/sse-power-distribution.pdf
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Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-1
19. Health
19.1. Introduction
19.1.1. This chapter identifies the potential health and wellbeing effects (both adverse
and beneficial) of the Proposed Development.
19.1.2. The information has been consolidated, following a request from the Health
Protection Agency (HPA), into a single chapter for the purposes of ensuring
health related information is in a readily accessible place for interested parties.
19.1.3. The assessment draws on the findings of other technical assessments, as set out
in various chapters of this this PEI Report, namely Chapter 9: Socio-economics;
Chapter 10: Traffic and Transport; Chapter 11: Air Quality, Chapter 12: Noise and
Vibration; and Chapter 13: Ground Conditions.
19.1.4. Where potential for specific health and wellbeing impacts are identified in a
technical assessment, this chapter will set out the significance of effect on the
receptors identified and any specific health mitigation required.
Consultation
19.1.5. A scoping request was submitted to the Planning Inspectorate in February 2013
to allow stakeholders the opportunity to comment on ES.
19.1.6. A summary of the scoping request responses that relate to health are presented
in Table 19-1.
Table 19-1: Relevant Scoping Opinion Responses
Stakeholder Comment Addressed within the Report
Health Protection Agency (HPA) – Public Health England
Health impacts should be consolidated into a separate chapter of the ES or carried out as a separate HIA.
This chapter is provided in direct response to this request. A summary of impacts related to health are presented in Table 19-2.
The health chapter or HIA should consider potential health impacts associated with the electric and magnetic fields around substations and the connecting cables or lines.
The potential impacts of electric and magnetic fields are addressed in section 19.3
The EIA should give consideration of the COMAH Regulations (Control of Major Accident Hazards) and the Major Accident Off-site Emergency Plan (Management of Waste from Executive Industries) (England and Wales) Regulations 2009.
Consideration is given to the COMAH Regulations in Chapter 13: Ground Conditions. Seabank 1 & 2 already Emergency Plan in place. The Proposed Development will be incorporated into this plan as described in Chapter 4: Project Description.
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Overview of the Proposed Development Site
19.1.7. The Proposed Development Site is located in an area of approximately 19ha
situated immediately east of the existing Seabank 1 & 2 station and wholly
located within the administrative boundary of SGC. The Site is within a
predominantly industrial area north of Avonmouth and constitutes a relatively flat
area of open, uneven grassland. The nearest receptors to the Site boundary are
the local industrial properties to the north and southwest, and the agricultural land
to the east. A detailed site description can be found in Chapter 3: The Site and Its
Surrounds. A description of the development is provided in Chapter 4: Project
Description.
19.2. Assessment Methodology and Significance Criteria
19.2.1. There is no single guidance associated with the scope and method of HIA for the
assessment of development projects nor is there a mandatory methodology for
assessing NSIPs. There is however a series of guidance documents prepared for
a variety of land use or public health situations. In undertaking this assessment
we have reviewed the following guidance:
• Healthy Urban Development Unit: Rapid Health Impact Tool (Ref. 19-1);
• Merseyside Guidelines for Health Impact Assessment (Ref. 19-2).
19.2.2. This assessment is based on the residual effects identified in the PEI Technical
Chapters 9-13. These effects are analysed against the baseline conditions set
out in the community profile to determine if there is likely to be a direct or indirect
health effect:
• Direct influences – e.g. atmospheric pollutant deposition, severance,
delays, noise, land contamination;
• Indirect influences – e.g. road safety, access to work and employment.
19.2.3. This assessment has considered the likely health effects in a qualitative manner
as it is not practical to quantify the nature of these effects against a standardised
methodology or criteria. However the assessment of each health effect is
described using the scale presented in Table 19-2.
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Table 19-2: Scale of Health Effects
Effect category Description
Beneficial A perceived or predicted improvement to health of workers, local residents and members of the community, or recreational users, which can be categorised as major, moderate or minor if sufficient information is available.
Negligible No discernible health effect
Adverse A perceived or predicted deterioration to health of workers, local residents and members of the community, or recreational users, which can be categorised as major, moderate or minor if sufficient information is available.
19.2.4. At present, it is anticipated that the main potential effects to human health arising
from the Proposed Development will result from changes to local air quality and
traffic and transport, during the construction, operation and demolition stages of
the Proposed Development. However, as with any project of this magnitude,
there are also potential effects arising from contaminated land, road safety and
noise impacts.
19.2.5. The assumptions that underpin this assessment are:
• The methodology for each assessment and significance criteria is
provided in each of the technical chapters stated within this PEI Report;
• All mitigation measures listed in the technical chapters are assumed to be
implemented;
• Baseline health data is based on 2009-2011 Public Health England data
sources.
Receptors
19.2.6. Health receptors include members of the public working or living in the vicinity of
the Site (including workers), that can potentially be affected by a source such as
ground contamination, air quality or noise. As shown in Plate 19-1 receptors only
become exposed to contamination via a pathway. Receptor sensitivity can vary in
relation to health, age and duration of exposure and different receptors are likely
to be affected by different stages and activities of the project e.g. construction
and operation.
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May 2014 Page 19-4
Plate 19-1: Source Pathway
19.2.7. The nearest residential communities to the Proposed Development Site are
located approximately 1.5km north of the Proposed Development Site in Severn
Beach, together with a small number of farms located approximately 1.1km
southeast.
19.2.8. The larger communities of Avonmouth and Bristol are located some 5km
southwest and 10km south east of the Proposed Development Site respectively.
19.2.9. The nearest residential properties to the proposed cooling water pipeline corridor
are situated approximately 800m east of its most southern point (near the
WWTW). There are no residential properties closer than 800m between the
WWTW and Seabank 1 & 2, as shown in Figure 3-5 in Volume III of this PEI
Report.
19.2.10. Chapter 11: Air Quality states that construction dust emissions and construction
plant exhaust emissions are unlikely to affect health receptors beyond 300m of
the construction site boundary. Road traffic emissions are also unlikely to be an
issue beyond 200m from the road source. The potential for air emissions to affect
health is therefore considered to be limited to the operational emissions
associated with the CCGTs and peaking plant.
19.2.11. Health receptors for each area of impact are described in more detail within
Chapters 9-18 and depicted in the constraints plan in Figure 3-5, Volume III of
this PEI Report.
19.3. Baseline Conditions
19.3.1. This section considers the existing community profile in the study area, taken to
be the Bristol and South Gloucestershire region. This includes the current health
status of the population.
19.3.2. Health profiles for each local authority area are produced annually by Public
Health England (PHE) and these provide a summary of the health of people
within defined areas and a comparison of local health with average values for all
areas of England. Health profiles have been obtained from PHE for Bristol and
South Gloucestershire (Ref. 19-3).
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19.3.3. Further data on Bristol and South Gloucestershire has been obtained through the
Joint Strategic Needs Assessment (JSNA). JSNAs have been produced by both
South Gloucestershire (Ref. 19-4) and Bristol City Council (Ref. 19-5).
19.3.4. The health of people living in South Gloucestershire is generally better than the
average of England as a whole while the health of people living in Bristol is varied
when comparing life expectancy, deprivation, infant mortality and causes of
premature mortality such as smoking and obesity (Ref. 19-3).
19.3.1. A summary of the data obtained from the 2013 PHE Health Profiles for the
individual local authorities is provided in Table 19-2. The red text indicates a
higher than average value in England, whilst the green text indicates a lower than
average value.
Table 19-3: Health indicator data for England, South Gloucestershire and Bristol
Health indicator England Average
South Gloucestershire
Bristol
1. Deprivation 20.3% 0.5% 25.8%
2. Long term unemployment 9.5 4.3 11.0
3. Life expectancy male 78.9 80.7 78.0
4. Life expectancy female 82.9 84.6 82.6
5. Infant death 4.3 2.3 2.7
6. Adults smoking 20.0% 16.5% 21.0%
7. Obese adults 24.2% 26.2% 22.7%
8. Obese children Year 6 19.2% 15.3% 19.1%
9. Smoking related deaths 201 159 219
10. Early deaths – heart disease and stroke
60.9 41.9 63.3
11. Early deaths- cancer 108.1 95.7 120.7
12. Road injuries and deaths 31.5 23.2 41.9
1 % people in this area living in 20% most deprived areas in England, 2010; 2 Crude rate per 1,000 population aged 16-64, 2012; 3 At birth, 2009-2011; 4 At birth, 2009-2011;5 Rate per 1,000 live births, 2009-2011; 6 % adults aged 18 and over, 2011/12; 7 % adults, modelled estimate using Health Survey for England 2006-2008; 8 % school children in Year 6 (age 10-11), 2011/12; 9 Directly age standardised rate per 100,000 population aged 35 and over, 2009-2011; 10 Directly age standardised rate per 100,000 population aged under 75, 2009-2011; 11 Directly age standardised rate per 100,000 population aged under 75, 2009-2011; 12 Rate per 100,000 population, 2009-2011
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Life Expectancy
19.3.2. Life expectancy is a good indicator for the overall health of a population. Based
on the most recent 2009-2011 data, life expectancy at birth for both men and
women is higher than the England average in South Gloucestershire. In Bristol
the life expectancy for men is 0.9 years lower than the England average, while for
women it is 0.3 lower than the England average.
19.3.3. Both the male and female average life expectancy values for South
Gloucestershire and Bristol are shown in Table 19-4.
Table 19-4: Life Expectancy from Birth (Ref. 19-3)
Location Female Average (years) Male Average (years)
England 82.9 78.9
Bristol 82.6 78.0
South Gloucestershire 84.6 80.7
Health Inequalities and Deprivation
19.3.4. The Marmot Review recognises health inequalities are a directly linked to
differences in population health (Ref. 19-6).
19.3.5. In general, health inequalities in Bristol and South Gloucestershire mirror those
nationally and they are well documented between individual areas within each
local authority.
19.3.6. Seven components are factored into the Index of Multiple Deprivation (IMD)
score: values for income; employment, health deprivation and disability;
education skills and training; housing; geographical access to services; and living
environment. In South Gloucestershire, multiple deprivation is lower than average
(0.5), while in Bristol multiple deprivation is higher (25.8) than the England
average (20.3).
19.3.7. The estimated level of adult obesity in South Gloucestershire is worse than the
England average, while in Bristol the level is better than the England average. In
relation to children, in Year 6, 15.3% of children are classified as obese in South
Gloucestershire compared to 19.1% in Bristol, both lower than the England
average of 19.2%.
19.3.8. In South Gloucestershire, life expectancy between the least deprived and most
deprived differs by 6.2 years for men and 4.8 years for women. In comparison,
life expectancy in Bristol is 9.4 years lower for men and 5.8 years lower for
women in the most deprived areas of Bristol than in the least deprived areas.
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19.3.9. Long term unemployment is another indication of deprivation and is a key
determinant of health. In South Gloucestershire long term unemployment was
lower than the England average while in Bristol long term unemployment was
higher than the England average.
Premature Mortality
19.3.10. In both South Gloucestershire and Bristol over the last 10 years, all causes of
mortality have fallen. This includes, on average, reduced early death rates from
cancer and from heart disease and stroke.
19.3.11. Smoking related deaths continue to be a major cause of premature mortality and
in Bristol the rates are worse than the England average while in South
Gloucestershire the rates are better than the England average.
19.3.12. The rate of road injuries and deaths in South Gloucestershire and Bristol is better
than the England average.
19.3.13. The premature mortality rate (defined as deaths from all causes under 75 years)
is also an important indicator of the overall health of the population. The
premature mortality rate in South Gloucestershire is lower than the England. In
Bristol the premature mortality rate has fallen gradually over recent years, but
remains steadily higher than the England average.
19.3.14. Cancer and cardiovascular disease remain the two main causes of death in
South Gloucestershire and Bristol. In South Gloucestershire rates are below the
national average while in Bristol rates are worse than the England average.
19.3.15. The most common forms of respiratory disease include chronic obstructive
pulmonary disease (COPD) and emphysema (both strongly related to tobacco
smoking), asthma (related to allergy, exercise and lung infection) and a variety of
infections of lung tissue. Although COPD death rates in men are slowly
decreasing, rates in women are increasing in South Gloucestershire. This is a
similar pattern to death rates from lung cancer and it reflects long term trends in
smoking (Ref. 19-3). The prevalence of COPD in Bristol is higher than the
England average.
Future Baseline
19.3.16. The future baseline conditions are not anticipated to be significantly different to
the existing baseline conditions. As described in Chapter 11: Air Quality the
assessment predicts a slight improvement in ambient pollutant concentrations.
Mean annual NO2 is likely to be the key pollutant of concern to human health and
is predicted to reduce from a background concentration of 23.0µg/m3 to
18.1µg/m3 between the present-day and 2019 without the Proposed
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Development (this is the earliest date the Proposed Development could
theoretically be commissioned). This is a result of more rigorous environmental
legislation and improved vehicle emissions in the UK and represents
approximately 45% of the National Air Quality Strategy objective for mean annual
NO2 (of 40µg/m3) in 2021.
19.4. Development Design and Impact Avoidance
19.4.1. A number of impact avoidance measures have been incorporated into the project
design that is relevant to health effects.
19.4.2. Chapter 9: Socio-economics notes that the Proposed Development incorporates
a new PROW to provide cyclist and footpath access from Ableton Lane to the
existing roundabout that is situated immediately east of the Proposed
Development Site. This new PROW will also incorporate a bridleway for horse
riders.
19.4.3. There are no specific health impact avoidance measures that have been
implemented in the design of the Proposed Development relevant to traffic and
transport, however a number of avoidance measures have been included that are
relevant to air quality, as discussed in Chapter 11: Air Quality. In particular:
• The Proposed Development has been designed such that process
emissions to air will comply with the emission limit values specified in the
Industrial Emissions Directive. This will be enforced by the EA through the
Environmental Permit required for the operation of the generating station;
• The stack heights have been optimised with consideration given to
minimisation of ground level air quality impacts, against the visual impacts
of taller stacks. Preliminary dispersion modelling was undertaken to
determine the optimum stack height range and local residents informally
consulted regarding their preference;
• The proposed locations of the peaking plant and its stacks was modified
during the design evolution, as outlined in Chapter 6: Project Need and
Alternatives, when preliminary dispersion modelling demonstrated that a
lower stack height and lower offsite effects could be achieved by moving
this plant further from the HRSG buildings.
19.4.4. The design of the Proposed Development has also been carried out in
conjunction with the acoustics consultants to identify locations and building
orientations that would minimise the noise impact at nearby noise sensitive
receptors, as discussed in Chapter 12: Noise and Vibration. Noise mitigation
measures that were analysed during the preparation of the concept layout
included building cladding. The chosen layout considers the findings of the noise
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assessment, along with other appraisals of potential environmental impacts and
constructability and maintainability factors to achieve an optimal layout.
19.4.5. Chapter 13: Ground Conditions notes that the Proposed Development
incorporates a minimum 8m buffer strip alongside the southern side of the
realigned Red Rhine for access by the LSIDB. This should inherently reduce
pollution risks of this watercourse during construction and thereafter , by creating
a natural setback from this watercourse.
19.5. Potential Effects and Mitigation Measures
19.5.1. It is anticipated that effects on health have the potential to arise from the
following sources:
• Construction phase – atmospheric pollutant deposition, traffic, noise, land
contamination;
• Operation Phase – plant emissions, construction dust atmospheric
pollutant deposition, traffic, noise; and
• Decommissioning Phase – as for construction phase.
19.5.2. Each of these potential effects has been considered and reported on in the
preliminary technical assessments within this PEI Report and a summary is
provided below.
Construction Phase Disturbance and Nuisance
Traffic and Transport
19.5.3. As reported in Chapter 10: Traffic and Transport a maximum increase of 6-7% is
predicted at the junction A403 / Severn Road / Chittening Road during the
enabling works and approximately 12% increase during the peak month of the
construction phase. This level of change during the peak month of traffic
generation is considered to be negligible. The effect during other months and
activities is expected to be less, and therefore also negligible. Based on the
conclusions in Chapter 10: Traffic and Transport, and the minimal increase in
traffic from the construction, there is not predicted to be an effect on delays in
vehicles at the junction and therefore the effect on public health is considered to
be negligible.
19.5.4. The A403 is the main pedestrian and cycling route in the study area assessed in
Chapter 10: Traffic and Transport. The predicted increase in total vehicles is
expected to be approximately four vehicles during peak hours along this route
during the enabling phase, prior to any mitigation for HGVs. During the peak
month of the construction phase, a total increase of 53 and 43 vehicles (including
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HGVs) is expected during the morning (0800-0900) and evening (1700-1800)
peak hours. Given the current level of pedestrian and cyclist activity along the
study roads, it is considered unlikely that temporary increases in traffic during
enabling works and the construction phase would result in difficulties for
pedestrians and cyclists to cross the A403. Chapter 10: Traffic and Transport
concludes the effect of severance during all phases of the Proposed
Development is negligible. Based on this conclusion the effect on public health
is considered to be negligible.
19.5.5. The risks of vehicular accidents associated with the Proposed Development is
likely to be localised to the construction site given that construction is temporary,
the changes predicted are temporary, and the estimated hourly traffic generation
is low relative to the total flows on the roads. With successful adoption of the
mitigation measures outlined within Chapter 10: Traffic and Transport it is
therefore considered unlikely that there would be an effect upon road safety and
accident levels due to Proposed Development traffic. Chapter 10: Traffic and
Transport concludes the risk of accidents is negligible and therefore the effect
on public health is therefore deemed to be negligible.
Air Quality
19.5.6. The predicted residual effect of dust emissions and deposition during enabling
works and construction of the Proposed Development is anticipated to be minor
adverse on sensitive receptors. Dust deposition does not directly lead to any
health effects however (once deposited it is not inhaled unless it is entrained in
the air again) and it would be temporary in nature, lasting only for the duration of
works onsite. Airborne particulate matter should only be a concern within the
immediate proximity to the construction works (e.g. 30-50m) and is therefore not
a concern to local residential dwellings (which are 1.1km from the Proposed
Development Site).
19.5.7. The residual effect of airborne particulate matter and atmospheric emissions
associated with construction plant and road traffic exhaust emissions is predicted
to be negligible, largely due to the large distance between the Site and any
sensitive receptors which allows significant dispersion of emissions.
Noise and Vibration
19.5.8. The predicted construction noise levels were assessed against the daytime and
night-time Threshold Values derived from the BS 5228 ABC method for
assessing the noise effects from construction activities. Predictions have shown
that noise levels from standard construction activities will fall below the Threshold
Values at the selected residential receptors during all construction activities
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during both daytime and night-time periods. A negligible significance of effect
has therefore been predicted.
19.5.9. Noise levels from construction traffic during the construction phase are not
expected to result in a perceptible change in noise according to the noise criteria.
A negligible significance of effect has therefore been predicted for road traffic.
19.5.10. Chapter 12: Noise and Vibration provides a number of mitigation measures and
states the contractor will employ Best Practicable Means in order to ensure that
construction noise is kept to a minimum.
19.5.11. Based on this conclusion the effect on public health arising from noise is
considered to be negligible.
Ground Contamination
19.5.12. Potential sources of contamination have been identified within Chapter 13:
Ground Conditions. The Proposed Development is proposed to be constructed
on previously undeveloped land, however the surrounding land uses could have
affected the Proposed Development Site soil and groundwater quality. The
surrounding land uses are predominantly industrial and agricultural.
19.5.13. Construction workers are the main receptor during the construction phase in
relation to contamination; it is not expected that people offsite would be affected.
Industry standard mitigation measures are outlined within Chapter 13: Ground
Conditions and include provisions for detailed site investigation, risk assessment
and remediation design and implementation for example.
19.5.14. Contamination within soils has the potential to adversely affect the health of
construction workers without appropriate duty and care. Health and safety
measures will be implemented to protect the construction workers’ health; for
example the appropriate use of PPE, hygiene practices and decontamination
units, if required.
19.5.15. Prior to the commencement of excavation works appropriate steps including a
detailed survey of the services locations and depths will be taken to ensure that
construction activities do not disturb any live services and reduce the risk of
disturbing existing utilities to negligible significance.
19.5.16. Encountering unexploded ordnance (UXO) onsite during piling and excavation
represents a potential major effect to the safety of construction workers. A UXO
study has already been undertaken for the Proposed Development Site. A further
UXO desk study report will be commissioned prior to construction, to fully assess
the risk of encountering UXO on site and recommend any mitigation measures
required to render potentially adverse effects negligible. Such mitigation
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measures may include the presence of an Explosive Ordnance Disposal
Engineer on site to supervise open excavations and down-hole intrusive
magnetometer surveys of all deep intrusive works and target investigation of
suspect anomalies. Following this mitigation, such as the removal of identified
UXO, where required, and taking into account the low risk of occurrence, the
significance of this effect is considered to be negligible.
19.5.17. After implementation of the mitigation measures, the effect on the public health of
construction workers is expected to be negligible.
Socio-economics and Employment
19.5.1. As described in the Marmot Review employment is a key determinant of health
(Ref. 19-6). The relationship between socio-economic position and educational
outcome has significant implications for subsequent employment, income, living
standards, behaviours and mental health (Ref. 19-6).
19.5.2. As outlined in Chapter 9: Socio-economics, the Proposed Development and
associated infrastructure is expected to lead to an additional 840 FTE jobs during
peak construction.
19.5.3. In general, the initial job and income growth for the construction workforce
associated with employment at the Proposed Development translates into further
spending and rising incomes throughout the community. This can have positive
impacts on individuals, families, neighbourhoods and communities, for instance,
in decreased crime, drugs, and family disruption, and increased and
strengthened security, education, healthcare for the infirm and elderly. Based on
the assessment provided in Chapter 9: Socio-economics, the effect on public
health is considered to be beneficial.
19.5.4. In addition to the direct construction employment generated by the Proposed
Development there would be an increase in local employment arising from
indirect and induced effects of the construction activity. Employment growth
would arise locally through manufacturing services and suppliers to the
construction process (indirect or supply linkage multipliers). Additionally, part of
the income of the construction workers and suppliers would be spent in the
Bristol Travel To Work Area, generating further employment. Therefore based on
the assessment in Chapter 9: Socio-economics, the effect on public health is
considered to be beneficial.
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Operational Phase
19.5.5. It is envisaged that the plant will have a design life of 30 years, with an operating
life possibly beyond this.
Traffic and Transport
19.5.6. Chapter 10: Traffic and Transport indicates that the effect of traffic flows during
operation is predicted to be negligible following mitigation. It identifies that travel
plan measures such as shuttle bus services and car sharing schemes will be
introduced and this will be outlined in the Travel Plan that is submitted along with
the final ES.
19.5.7. The delivery of a new PROW is anticipated to lead to a minor beneficial effect on
pedestrian and cyclist amenity. Therefore there is anticipated to be an overall
beneficial effect on the public health of the receptors in relation to increased
opportunities of cycling and walking.
Air Quality
19.5.8. Chapter 11: Air Quality models the likely effect of operational emissions from the
Proposed Development, including the increase in concentrations due to
additional traffic flows. The chapter concluded the impact of air quality will be
negligible.
19.5.9. The maximum process contribution of NO2 from any of the operational scenarios
results in a ‘low’ change in the annual mean concentration at four of the identified
receptors. The ambient concentration at these receptors is well below the
objective with the Proposed Development, therefore the significance of the effect
at these receptors is predicted to be negligible. The magnitude of change at all
other human health receptors is very low and the significance of effect is also
negligible.
19.5.10. The magnitude of change in annual mean NO2 concentration at the identified
nearest AQMAs from the Proposed Development is ‘very low’; therefore the
significance of effect at the AQMAs is considered to be negligible.
19.5.11. The maximum short-term predicted concentration of NO2 at the worst affected
receptor (the PROW immediately south of Proposed Development) represents
less than 7% of the daily mean national Air Quality Strategy objective and is
considered to be insignficiant according to EA guidance. The Proposed
Development short term contribution to hourly mean NO2 is considered to have a
negligible effect on human health.
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-14
19.5.12. The maximum short-term and long term process contributions of PM10, CO and
other pollutants at the worst affected receptors represent ‘very low’ changes in
the concentration over the appropriate averaging periods, which are considered
to have a negligible effect on human health.
19.5.13. Based on this conclusion the effect on public health is considered to be
negligible.
Noise and Vibration
19.5.14. Chapter 12: Noise and Vibration models operational noise for the Proposed
Development. With mitigation in place to meet the specified reduction in
equipment noise levels during design, the residual effect from the operation of
the Proposed Development is predicted to be negligible for all receptors. Based
on the conclusions presented in Chapter 11: Noise and Vibration, the effect on
public health from operational noise and vibration is therefore considered to be
negligible.
Ground Conditions
19.5.15. There are not anticipated to be any potential effects on human health from
ground conditions during operation.
Socio-economics
19.5.16. Maintenance, administrative roles and shift workers will be required in operational
phase of the Proposed Development as outlined in Chapter 9: Socio-economics.
Up to 40 jobs FTE are expected to be created by the operational Proposed
Development, which is likely to have a number of positive effects for those
employed. Based on the assessment described in Chapter 9: Socio-economics
the effect on public health is anticipated to be beneficial.
Electromagnetic Fields (EMF) and Health
19.5.17. The UK Government sets guidelines for exposure to EMF on the advice from the
HPA’s Centre for Radiation, Chemical and Environmental Hazards. Guidelines
published by the International Commission on Non-Ionising Radiation Protection
(ICNIRP) (Ref. 19-7) were adopted by the UK Government in 2004 and a further
code of practice has been produced by Department of Energy and Climate
Change (DECC) (Ref. 19-8). Furthermore the World Health Organisation (WHO)
has also produced a fact sheet on EMF and Public Health (Ref. 19-9).These
guidelines include reference and permitted levels of exposure as detailed in the
following section.
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-15
19.5.18. The ICNIRP “reference levels” for the public are:
100 µT for magnetic fields; and
5,000V/m for electric fields.
19.5.1. Both the transmission and distribution assets associated with the Proposed
Development have each been assessed for compliance against Government
guideline limits documented in NPS EN-5 (Ref. 19-10). A summary of the
reference levels in comparison to typical ground-level UK field levels from
overhead power lines (Ref. 19-11) are shown in Table 19-5.
Table 19-5: ICNIRP Reference Levels vs Typical Ground-level UK Field Levels from
Overhead Power Lines
Electromagnetic Fields Magnetic Electric
ICNIRP “reference levels” for the public
100 µT 5,000 V/m
275kV- 400kV 5-10 µT 3,000 – 5,000 V/m
132kV 0.5-2 µT 1,000 – 2,000 V/m
33kV- 11kV 0.2 -0.5 µT 200 V/m
19.5.2. A number of existing buried and above ground services are already present on
the Proposed Development Site with 400kV, 132kV and 11kV OHLs crossing the
CCR Site in an east to west direction, and with five pylons on the CCR Site.
19.5.3. The Proposed Development includes the installation of new 400kV electrical
connection approximately 440m long and routed through the existing Seabank 1
& 2 station to Seabank Substation. The proposed connection will be either
underground and/or on a cable rack approximately 2m above ground. In addition,
the existing 11kV connection will be routed underground in a north to south
direction across the eastern part of the Generating Station Site as part of the
Proposed Development.
19.5.4. The strength of a magnetic field decreases dramatically with increasing distance
from the source (Ref. 19-10). The nearest residential properties are located more
than 1.1km from the Proposed Development, with existing overhead lines much
closer than this currently. Therefore the effect of the proposed electrical
connection is likely to be indiscernible from background levels at these residential
dwellings.
19.5.5. The strength of a magnetic field will be higher at the local PROW, however
exposure would be short-term and still approximately 400m from the proposed
electrical connection (including the proposed PROW), which is sufficient to
render its effects negligible. As mentioned above, the proposed connection may
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-16
be underground, which would further reduce any potential effect, as well as
moving the 11kV connection underground which currently runs close to one of
the PROW in Crook’s Marsh.
19.5.6. Taking the above into account, and the fact the Proposed Development will be
constructed and operated in compliance with the ICNIRP Guidelines on EMF,
there are negligible residual impacts from EMF associated with the operation of
the project. Based on this conclusion the effect of EMFs on public health is
considered to be negligible.
Safety and Emergency Planning
19.5.7. As outlined in Chapter 4: Project Description the Applicant will develop an
Emergency Planning and Response Management Plan similar to that used for
Seabank 1 & 2 site such that emergency planning and response control
measures are implemented to:
• Mitigate the potential effects to persons, environment, assets or company
reputation;
• Respond to catastrophic plant and process incidents such as fires,
explosions, release of hazardous substances or large releases of energy;
• Respond to external incidents which have the potential to cause
incidents described above e.g. nearby facility emergency, flood,
malevolent actions, earthquake or aircraft crash; and
• Communicate with stakeholders such as neighbours, media or
regulators.
19.5.8. The Emergency Planning and Response Management Plan will be tailored to the
Proposed Development. This Plan is applied at all operational SSE sites and
includes any site specific requirements.
19.5.9. Fire safety methods will build upon those methods already practiced at the
Seabank 1 & 2 site. Fire safety management is applicable to the entire
Generation Station Site and is further addressed in this section.
19.5.10. Following implementation of these safety measures, the risk of an emergency
onsite affecting worker or community health is considered to be negligible.
Decommissioning Phase
19.5.11. It is not anticipated that the decommissioning phase would have the potential to
cause any significant health issues. The significance of effects associated with
decommissioning are expected to be similar to construction, albeit for a slightly
shorter duration.
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-17
19.5.12. The greatest risk of health effects is to workers onsite, although following
adequate health and safety measures as outlined in Chapter 10; Ground
Conditions, this too is expected to be of negligible significance.
19.6. Residual Effects
19.6.1. A summary of residual effects for both the construction and operational phase is
presented in Table 19-6.
Table 19-6: Summary of Residual Effects (post-mitigation)
Assessment Chapter Topic Impact Geographic Scale
Health effect
category
Construction phase
Chapter 11: Air Quality; Chapter 12: Noise and Vibration
Disturbance and nuisance
Impacts from dust, emissions, road traffic; onsite machinery
Local; Regional
Negligible
Chapter 10: Traffic and Transport
Transport and access
Impact on severance, driver delay, pedestrian and cyclist delay, fear and intimidation, accident and safety.
Local Negligible
Transport and access
Impact on pedestrian and cyclist amenity – creation of new PROW
Local Beneficial
Chapter 13: Ground Conditions; Chapter 14: Flood Risk, Hydrology and Water Resources
Contamination Pathways
Impacts from contaminated land; pollution. Local Negligible
Chapter 9: Socio-economics
Socio-economics and employment
Additional employment Local; Regional
Beneficial
Operational Phase
Chapter 10: Traffic and Transport; Chapter 11: Air Quality; Chapter 12: Noise and Vibration
Disturbance and nuisance
Impacts from dust, road traffic; onsite machinery
Local; Regional
Negligible
Chapter 13: Ground Conditions; Chapter 14: Flood Risk, Hydrology and Water Resources
Contamination Pathways
Impacts from re-use of soils, importation of materials to site Local
Negligible
Chapter 10: Traffic and Transport
Transport and access
Impact on severance, driver delay, pedestrian and cyclist delay, fear and intimidation, accident and safety
Local Negligible
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-18
Assessment Chapter Topic Impact Geographic Scale
Health effect
category
Chapter 9: Socio-economics
Socio-economics and employment
Impact of employment and local economy
Local; Regional
Beneficial
Chapter 19: Health Electromagnetic Fields (EMF) and Health
Impact of EMF from overhead and underground lines
Local Negligible
Chapter 4: Project Description
Safety and Emergency Planning
Emergency event onsite such as a fire
Local; Regional
Negligible
19.6.2. Based on this assessment it is expected that the Proposed Development will
have a negligible effect on the health of the receptors following mitigation, with
the exception of two beneficial effects:
• A beneficial effect during operation associated with the production of a
new PROW, which will help encourage walking and cycling by local
residents and workers in Severnside;
• Beneficial effects during construction and operation associated with
employment generation, which is recognised by the Marmot Review as
having potential health benefits.
19.7. Cumulative Effects
19.7.1. This section assesses the effect of the Proposed Development and associated
infrastructure in combination with other developments in the area, as outlined in
Chapter 7: Assessment Methodology, and their potential to cause cumulative
health effects.
19.7.2. There are a number of cumulative schemes in the local area that have the
potential to effect health, such as the Hinkley C Connection project which
comprises a long-distance 400KV OHL. However, the potential for cumulative
EMF effects has not been considered further given that the Proposed
Development has a negligible contribution to changes in EMF.
19.7.3. The key aspect with the potential for cumulative effects is considered to be air
quality, which is discussed further below. Given the distance from the Proposed
Development Site to the nearest residential dwellings, it is not expected that
there would be cumulative noise effects. It is also anticipated that these
developments when considered along with the Proposed Development should
not give rise to increased effects from traffic and transport, ground conditions and
socio-economics.
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-19
19.7.4. The Severnside Energy Recovery Centre and Avon Power Station schemes are
sufficiently close to the Proposed Development and of sufficient scale to have the
potential to contribute to cumulative effects to air quality on identified receptors,
according to Chapter 11: Air Quality. These have been modelled together with
the Proposed Development in Chapter 11: Air Quality to determine the overall
potential cumulative effect. The predicted concentrations from cumulative source
air quality modelling indicate that the additional contributions from the Proposed
Development are unlikely to result in exceedance of hourly or annual mean
National Air Quality Strategy objectives at the worst-affected human health
receptors. For this reason the effects on public health from cumulative air quality
are considered to be negligible.
19.8. Impacts and Effects yet to be Determined
19.8.1. The technical chapters in this PEI Report have identified a number of impact and
effects yet to be determined as part of the EIA process, which will need to be
considered in the updated health chapter as part of the ES.
19.8.2. The scheme design may be subject to change prior to submission of the final
DCO application. Any changes that lead to differing or new impacts and effects
will be highlighted within the final ES, along with the reasons for the change.
19.8.3. It is also possible that the baseline conditions will change between the
preparation of this PEI Report and the final ES; aspects such as air quality and
noise conditions are dynamic and evolve over time. The Proposed Development
Site is currently subject to excavation, top soil stripping, and levelling in certain
areas in order for third parties to deliver the Spine Access Road and new channel
for the Red Rhine, which are discussed in Chapter 2: The DCO and EIA Process
and Chapter 7: Assessment Methodology. A haul road is also being constructed
through the middle of the Proposed Development Site to enable access by third
party from the roundabout to the east of the Site to the Severnside Energy
Recovery Centre to the west. These works onsite are being undertaken by other
developers, under extant planning permissions and are separate to the Proposed
Development.
19.8.4. The final ES will report on the baseline conditions considered relevant at the time
of submission, or an agreed point of time shortly before, as well as any changes
to the predicted magnitude of change or effects as a result of the changing
baseline conditions.
Seabank 3 PEI Report – Chapter 19 Health
May 2014 Page 19-20
19.9. References
Ref. 19-1 Healthy Urban Development Unit (2013) Rapid Health Impact
Toolhttp://www.healthyurbandevelopment.nhs.uk/wp-
content/uploads/2013/12/HUDU-Rapid-HIA-Tool-Jan-2013-Final.pdf
Ref. 19-2 Scott-Samuel (2001) Merseyside Guidelines for Health Impact
Assessment
Ref. 19-3 Public Health England (2013) Local Health Profiles:
www.apho.org.uk
Ref. 19-4 South Gloucestershire JSNA (2013)
http://hosted.southglos.gov.uk/oaof/documents/jsna/South%20Glou
cestershire%20JSNA%202013%20Section%203/Section%203.6%2
0Environment.pdf
Ref. 19-5 Bristol JSNA (2012)
http://www.bristol.gov.uk/sites/default/files/documents/health_and_a
dult_care/health/JSNA%204.%20Health%2C%20Wellbeing%20%26
%20Inequalities%20_v7_.pdf
Ref. 19-6 The Marmot Review (2010) Fair Society, Healthy Lives
http://www.instituteofhealthequity.org/projects/fair-society-healthy-
lives-the-marmot-review
Ref. 19-7 ICNRP (1998) Guidelines for Limiting Exposure to time-varying
electric, magnetic and electromagnetic fields (up to 300 GHz).
Health Physics 74 (4): 494-522.
Ref. 19-8 DECC Codes of Practice (2012)
https://www.gov.uk/government/uploads/system/uploads/attachment
_data/file/37447/1256-code-practice-emf-public-exp-guidelines.pdf
Ref. 19-9 WHO (2013) Electromagnetic fields and public health
http://www.who.int/peh-emf/publications/facts/fs322/en/
Ref. 19-10 National Policy Statement for Electricity Networks Infrastructure
(EN-5)
https://www.gov.uk/government/uploads/system/uploads/attachment
_data/file/37050/1942-national-policy-statement-electricity-
networks.pdf
Ref. 19-11 Energy Networks Association (2013) Engineering Recommendation
G92
http://www.energynetworks.org/modx/assets/files/electricity/she/emf
s/EMF_The_Facts_260613.pdf
Seabank 3 PEI Report – Chapter 20 Cumulative Effects
May 2014 Page 20-1
20. Cumulative Effects
20.1. Introduction
20.1.1. This chapter of the PEI Report assesses the effect of the Proposed Development
and associated infrastructure in combination with the potential environmental and
socio-economic effects of other consented developments in the area.
20.1.2. Cumulative effect interactions can occur as either interactions between effects
associated with just one project or interactions between the effects of a number
of projects in an area. As a result, two types of cumulative effect interaction have
been considered which are as follows:
• The combined effect of individual effects arising as a result of the
Proposed Development and associated infrastructure, for example
effects in relation to atmospheric emissions from the stacks and HGV
deliveries affecting a single receptor; and
• The effects of the Proposed Development and associated infrastructure
along with other development schemes which may, on an individual
basis be insignificant but, together (i.e. cumulatively), have a significant
effect.
20.1.3. In some EIA guidance documents, these two types of cumulative impact
interactions are referred to as ‘Type 1’ and ‘Type 2’ cumulative effects
respectively. Both types have been considered within each of the technical
chapters of this PEI Report.
20.1.4. Details of the other schemes considered within the cumulative effects
assessment can be found in Table 20-1 below and are discussed within Chapter
7: Assessment Methodology.
20.2. Legislation and Planning Policy Context
20.2.1. The requirement for cumulative impact assessment is clearly stated in the
relevant Directives and legislation as detailed below:
• European Directive 2011/92/EU (Ref. 20-1) on the assessments of
effects of certain public and private projects on the environment requires
the assessment of “the direct effects and any indirect, secondary,
cumulative, short, medium and long term, permanent or temporary,
positive and negative effects of the project”;
• Schedule 4 Part 1 of The Infrastructure Planning (Environmental Impact
Assessment) Regulations 2009 (as amended) (Ref. 20-2) requires “A
description of the likely significant effects of the development on the
Seabank 3 PEI Report – Chapter 20 Cumulative Effects
May 2014 Page 20-2
environment, which should cover the direct effects and any indirect,
secondary, cumulative, short, medium and long-term, permanent and
temporary, positive and negative effects of the development, resulting
from:
(1) The existence of the development;
(2) The use of natural resources;
(3) The emission of pollutants, the creation of nuisances and the
elimination of waste,
• and the description by the applicant of the forecasting methods used to
assess the effects on the environment”.
20.3. Assessment Methodology
20.3.1. Section 7.4.11 of Chapter 7: Assessment Methodology sets out the other
developments considered within the cumulative effect assessment, with their
locations illustrated on Figure 7-1, Volume III of this PEI Report.
20.3.2. The schemes included within the cumulative effect assessment have been
identified in consultation with SGC and BBC, and comprise those within a 6km
radius of the Proposed Development Site and which are more than 1ha in size.
20.3.3. Each technical specialist has reviewed the cumulative schemes to determine if
any could have potential cumulative effects with the Proposed Development and
associated infrastructure. Where no cumulative effects have been identified, this
is also stated.
20.3.4. Two types of cumulative effect interaction have been considered as part of this
assessment, which are discussed below.
Combined Effects – Type 1
20.3.5. The combination of predicted environmental effects resulting from a single
development on any one receptor that may collectively cause a greater (or
lesser) effect than each effect in isolation is referred to in this chapter as
‘combined effects’. An example could be the combination of atmospheric
emissions from the stacks and HGV deliveries affecting a single receptor
together, to cause a combined effect that is different to that assessed to occur
when each individual effect is considered in isolation.
Cumulative Effects – Type 2
20.3.6. Cumulative effects are those that accrue over time and space from a number of
developments. The effects of the Proposed Development are considered in
Seabank 3 PEI Report – Chapter 20 Cumulative Effects
May 2014 Page 20-3
conjunction with the potential effects from other projects or activities that are both
reasonably foreseeable in terms of delivery (e.g. have planning consent or are in
the planning process) and are geographically located in a position where
environmental impacts could act together to create an effect that is of more (or
less) significance overall than the effect of individual schemes alone.
20.3.7. Operational impacts are generally long-term, and whilst construction impacts are
often temporary, they can be of a great magnitude. Consequently, when
cumulative effects that could be associated with construction at one site and
operation at another are considered the difference in duration and reversibility is
considered within the assessment.
Effect Assessment and Significance Criteria
20.3.8. There is no standard prescriptive method for assessing cumulative and combined
effects and the extent to which effects of other developments can be assessed
quantitatively depends on the level of information available about the
development. Such effects are, therefore, assessed by professional opinion,
although matrices and modelling are used where appropriate and where enough
information regarding the other proposed developments exists. Effects are
quantified where possible but where environmental assessment information
regarding other developments is not available or uncertain, the assessment is
necessarily qualitative.
20.3.9. When considering the cumulative effects of the Proposed Development together
with other developments, mitigation measures as set-out in Chapters 9 - 19 have
been taken into account i.e. only residual (after mitigation) effects are discussed
in this chapter. Consideration of combined effects generally follows the
methodology set out in the Chapters referenced.
20.3.10. Cumulative and combined effects are assessed to be neutral, minor (not
significant), moderate or major (significant).
20.3.11. In reporting significance, it is appropriate to also acknowledge the relative
contributions different projects make to a cumulative effect, and carefully
consider whether a cumulative effect occurs at all. A large scale project might be
predicted to result in significant effects in its own right for example. The
cumulative effects of such a project with a smaller proposed development that
does not have significant effects should not conclude significant cumulative
effects unless an effect of greater significance is assessed to occur.
Consequently, care is taken not to simply propagate such effects as being
cumulative, but rather to focus on the nature and scale to which genuine
cumulative effects might result.
Seabank 3 PEI Report – Chapter 20 Cumulative Effects
May 2014 Page 20-4
20.3.12. Where applicable, the assessment considers all developments that have
potential for cumulative effects with the Proposed Development together, as a
worst case.
20.4. Combined Effects of Individual Effects -Type 1
20.4.1. The main Type 1 cumulative effect associated with the Proposed Development
and associated infrastructure is the combined effect of atmospheric emissions
from the stack and additional road traffic, as well as the combination of noise
emissions from the operational facility and HGV delivery traffic.
20.4.2. Chapter 11: Air Quality addresses this issue and demonstrates that, together,
there are no cumulative traffic and point source effects from the Proposed
Development as traffic impacts will occur during construction, while point source
impacts will occur during plant operation.
20.4.3. Chapter 12: Noise and Vibration demonstrates that the significance of operational
noise emissions is negligible to minor adverse at the worst affected dwellings,
regardless of whether HGV traffic is taken into account, and therefore is not
considered significant.
20.4.4. Specific mitigation measures for individual effects are addressed in the technical
chapters of this PEI Report. These measures will be incorporated into the CEMP.
20.5. Combined Effects of the Proposed Development with Other
Development Schemes – Type 2
20.5.1. As highlighted within the introduction to this chapter, the review of the combined
effects of the Proposed Development with other schemes (or ‘Type 2’ cumulative
effects) is presented within each of the technical chapters of this PEI Report.
20.5.2. Generally, it is not anticipated that the cumulative schemes would change the
significance of the predicted residual effects associated with the Proposed
Development and associated infrastructure. The exceptions to this, where
consideration of the cumulative schemes has increased the residual effects
identified within this PEI Report, are listed below in Table 20-1.
Table 20-1: Cumulative Effects of the Proposed Development with Other Development Schemes
Environmental
Aspect Potential for Cumulative Effect
Significance of
Cumulative Effects
Chapter 9:
Socio-
Economics
The combined effect of the Proposed Development with the
cumulative schemes in terms of operational jobs on the Bristol
Travel to Work Area (TTWA) and the South West economy.
Moderate
Beneficial
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May 2014 Page 20-5
Environmental
Aspect Potential for Cumulative Effect
Significance of
Cumulative Effects
Chapter 10:
Transport and
Access
The combined effect of construction traffic from the Proposed
Development with the cumulative schemes. The assessment
incorporates a number of conservative assumptions and is
based on the peak month of construction. The rest of the
construction period is expected to lead to less traffic and
deliveries are likely to be timed deliberately to avoid the peak
hours, thereby reducing the significance of effect.
Minor Adverse
(with the majority
of the construction
period negligible)
Chapter 11:
Air Quality
The combined effect of operational emissions from the
Proposed Development with the cumulative schemes at human
health and ecological receptors (including the worst-affected
area of the Severn Estuary SAC/SPA/Ramsar/SSSI).
Minor Adverse
Chapter 12:
Noise and
Vibration
The combined effect of operational noise emissions upon
residential receptors from the Proposed Development with the
cumulative schemes.
Minor Adverse
Chapter 15:
Archaeology
The combined effect on archaeological features from the
construction of the Proposed Development with the cumulative
schemes.
Minor Adverse
The combined effect on heritage features from the operation of
the Proposed Development with the cumulative schemes. Minor Adverse
Chapter 17:
Landscape
and Visuals
The combined effect of visual effects (at Year 15) from the
Proposed Development with the cumulative schemes. Minor Adverse
20.5.3. The only residual effect to have been elevated to a significant effect as a result of
considering the cumulative schemes is the moderate beneficial effect associated
with the job creation attributed to the operational Proposed Development and
cumulative schemes. The Proposed Development is predicted to generate a
minor benefit in isolation.
20.5.4. It is not expected that any other residual effects attributed to the Proposed
Development and associated development would change when taking into
account these cumulative schemes.
20.6. References
Ref. 20-1 European Directive 2011/92/EU
Ref. 20-3 The Infrastructure Planning (Environmental Impact Assessment)
Regulations 2009 (as amended)
Seabank 3 PEI Report – Chapter 21 Residual Effects
May 2014 Page 21-1
21. Residual Effects
21.1. Introduction
21.1.1. This chapter of the PEI Report provides a summary of the ‘residual effects’ associated with the Proposed Development and associated development, which are those effects that remain following the implementation of the mitigation measures presented in the preceding technical chapters.
21.1.2. Mitigation measures relate to each of the key phases (enabling works and construction of the plant; operation) of the Proposed Development and associated infrastructure, and are discussed in full in the relevant technical chapters of this PEI Report. In addition, each technical chapter also contains a detailed consideration of both positive (beneficial) and negative (adverse) residual effects arising.
21.1.3. The significance criteria applied to these effects is outlined in Chapter 7: Assessment Methodology of this PEI Report, and its application is also discussed within each of the technical chapters.
21.2. Background
21.2.1. Preparation of the EIA and evolution of the design of the Proposed Development have been undertaken in parallel, and as such, many mitigation measures have already been incorporated within the design parameters to eliminate adverse environmental and social effects before they occur – a process termed Impact Avoidance. These include, for example, determining the appropriate stack height to avoid significant effects on local air quality and designated sites, as well as HGV vehicle restrictions so as to avoid adverse effects to nearby communities and habitat sites
21.2.2. A CMS and CEMP will be prepared and approved by the local councils prior to the onset of the demolition and construction phase to maintain consideration of environmental effects beyond the planning stage of the Proposed Development. This will incorporate the commitments made within the PEI with regard to mitigating against potentially adverse effects throughout the enabling works, and construction phase (refer to Chapter 5: Enabling Works and Construction of this PEI Report).
21.2.3. The CEMP will address all relevant environmental issues including: noise and vibration, waste management, air emissions, hours of working and neighbourhood liaison.
21.2.4. Chapter 20: Cumulative Effects of this PEI Report addresses the potential effects taking into account the other nearby schemes identified in Chapter 7: Assessment Methodology.
21.3. Summary of Residual Effects
21.3.1. Table 21-1 provides a summary of the identified residual effects associated with the Proposed Development and associated infrastructure in the construction and operational phases.
Seabank 3 PEI Report – Chapter 21 Residual Effects
May 2014 Page 21-2
Table 21-1 Summary of Residual Effects
Chapter No. Project Phase Description Effect
Significance
9. Socio
Economics
Construction
Employment generation and supply chain
benefits during the construction phase
(direct, indirect and induced effects)
Moderate
Beneficial
Leisure, Recreation and Tourism Negligible
Operation
Employment generation and supply chain
benefits during the operational phase Minor Beneficial
Land use and Public Rights of Way (PROW) Minor Beneficial
Leisure, Recreation and Tourism Negligible
10. Traffic
and
Transport
Construction
Effects on Severance, Driver delays,
Pedestrian/cyclist delay, Fear and
intimidation, Accident and safety
Negligible
Effect on pedestrian/cyclist Amenity Negligible
Operation
Effects on Severance, Driver delays,
Pedestrian/cyclist delay, Fear and
intimidation, Accident and safety
Negligible
Effect on pedestrian/cyclist Amenity Minor Beneficial
11. Air
Quality
Construction
Exhaust emissions from construction site
plant/equipment Negligible
Exhaust emissions associated with HGV road
movements Negligible
Construction dust emissions Negligible
Operation
Point source emissions associated with the
operational development on human health Negligible
Point source emissions associated with the
operational development on ecosystems Negligible
12. Noise
and Vibration
Construction
Effect of construction activities onsite on
residential receptors Negligible
Effect of construction activities onsite on
ecological receptors Minor Adverse
Construction traffic noise Negligible
Construction vibration Negligible
Operation Operational noise (single or multi shaft) Negligible to
Minor Adverse
Seabank 3 PEI Report – Chapter 21 Residual Effects
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Chapter No. Project Phase Description Effect
Significance
13. Ground
Conditions
Construction
Soil and groundwater contamination Negligible
Ground Gas Negligible to Minor Adverse
Underground Structures and Unexploded Ordnance
Negligible
Storage of potentially contaminating
materials and accidental spillage Negligible
Operation
Accidental release of contaminating materials
and accidental spillage Minor Adverse
Degradation of soil and groundwater conditions
Negligible
14. Flood
Risk,
Hydrology
and Water
Resources
Construction
Water use and potential to affect water
quality Minor Adverse
Fluvial/tidal flood risk to third party land
associated with raising the Proposed
Development Site
Minor adverse
Increase in surface water runoff Minor Adverse
Operation
Water use and potential to affect water
quality Minor Adverse
Fluvial/tidal flood risk to the Proposed
Development Site following land raising Major Beneficial
Fluvial/tidal flood risk to third party land
associated with raising the Proposed
Development Site
Minor adverse
Increase in surface water runoff Minor Beneficial
15.
Archaeology
and Cultural
Heritage
Construction Effects on buried archaeology Minor Adverse
Effects on the setting of heritage assets Minor Adverse
Operation Effects on buried archaeology Negligible
Effects on the setting of heritage assets Minor Adverse
16. Ecology
Construction
Effects on designated sites offsite Negligible to
Minor Adverse
Effects on habitat integrity onsite Minor Adverse
Effect on Bats and flora Negligible
Effect on Breeding Birds, Non-breeding birds, Reptiles
Minor Adverse
Seabank 3 PEI Report – Chapter 21 Residual Effects
May 2014 Page 21-4
Chapter No. Project Phase Description Effect
Significance
Operation
Effects on designated sites offsite Negligible to
Minor Adverse
Effects on habitat integrity onsite Minor Adverse
Effect on Bats, breeding birds and flora Negligible
Effect on non-breeding birds and reptiles Minor adverse
17.
Landscape
and Visual
Impact
Construction
Landscape effects of construction Negligible to
Minor Adverse
Visual effects (all receptors except Crook’s
Marsh)
Negligible to
Minor Adverse
Visual effects on Crook’s Marsh PROW
(Receptor 10a)
Moderate
Adverse
Operation
Landscape effects of operation Negligible to
Minor Adverse
Visual effects (all receptors except Crook’s
Marsh)
Negligible to
Minor Adverse
Visual effects of operation in Year 1 from
PROW on Crook’s Marsh (Receptor 10a)
Moderate
Adverse
Visual effects of operation in Year 15 from
PROW on Crook’s Marsh (Receptor 10a) Minor Adverse
19. Health
Construction
Disturbance and nuisance from dust,
emissions, road traffic; onsite machinery, and
effects from contaminated land, pollution
Negligible
Effects on health arising from socio-economic
impacts and employment generation Minor Beneficial
Operation
Disturbance and nuisance to nearby
receptors from dust, emissions, road traffic;
onsite machinery
Negligible
Impact of EMF from overhead and underground lines
Negligible
Effects on health arising from socio-economic
impacts and employment generation Minor Beneficial
Safety and emergency planning Negligible
Provision of a new PROW to encourage
recreational activities and commuting by
cycling/walking
Minor Beneficial
Seabank 3 PEI Report – Chapter 21 Residual Effects
May 2014 Page 21-5
21.4. Summary and Conclusions
Construction Phase
21.4.1. The residual effects associated with enabling works and construction of the Proposed Development and associated infrastructure are considered short term, temporary and reversible. These effects have been assessed as being predominantly negligible or minor adverse.
21.4.2. No major effects have been identified within this PEI Report which would be considered significant; however the PEI Report has concluded that the Proposed Development will result in significant (moderate) beneficial socio-economic effects through the creation of jobs during the construction phase, whilst a moderate adverse visual effect is predicted for walkers on the PROW on Crook’s Marsh (Receptor 10a), albeit this will be temporary in duration and it is not a well-used PROW currently (because it ceases at the Proposed Development Site boundary).
21.4.3. A number of mitigation measures (or actions) have been outlined in the technical chapters which will be implemented during the enabling works and construction to ensure that these effects are minimised. These will be incorporated into the CEMP, which will be agreed with BCC and SGC prior to commencement of site works.
Operational Phase
21.4.4. The operational effects of the Proposed Development are predominantly negligible or minor. Moderate and major effects are discussed below.
21.4.5. A temporary moderate adverse visual effect is expected on users of the PROW on Crook’s Marsh (Receptor 10a) during the early years of operation, as the woodland blocks planted along the southern boundary would not have fully established by Year 1 of operation to filter views. Following growth of the woodland blocks and other planting the effect on users of this PROW is considered to reduce to minor.
21.4.6. A significant major beneficial effect on flood risk has been identified as a result of the proposed land raising, which will protect the Proposed Development Site from extreme flood events, without causing a significant adverse effect on neighbouring land through the displacement of this water.