Identification of Preferred Site Report

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A630 Deephams Sewage Works Upgrade

Identification of Preferred Site

Stage 3 Report

Public consultation version


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P1 A630 Identification of preferred site stage 3 report (public consultation version)

Identification of preferred site stage 3 report Page 2 of 58 June 2012

Revision Date File Name

Publicconsultationversion

June 2012 Description Identification of preferred site stage 3 report, published aspart of phase 1 public consultation

Prepared by Checked by

Name AB PH/NF/LG

Signature


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Table of Contents

1 EXECUTIVE SUMMARY ................................................................................................................... 62 INTRODUCTION ............................................................................................................................... 6

2.1

Section objectives ..................................................................................................................... 6

2.2 Background to the Deephams Sewage Works upgrade ........................................................... 72.3 Summary of the need for the upgrade....................................................................................... 72.4 Summary of the Assessment Methodology ............................................................................... 82.5 Structure of this report ............................................................................................................... 9

3 THE IDENTIFICATION AND ASSESSMENT OF SHORTLIST SITES ............................................. 93.1 Section objectives ..................................................................................................................... 93.2 Site assessment (stage 2a) ....................................................................................................... 93.3 Treatment options assessment (Stage 2b) ............................................................................. 103.4 How the shortlist sites were assessed in stage 3 .................................................................... 10

4 ASSESSMENT OF DEEPHAMS SEWAGE WORKS SITE ............................................................. 154.1 Section objectives ................................................................................................................... 154.2 The site .................................................................................................................................... 154.3 Summary of our conclusions at the site assessment (stage 2a) stage ................................... 164.4 Treatment options for assessment .......................................................................................... 164.5 Key outcomes from the assessment ....................................................................................... 17

5 ASSESSMENT OF MERIDIAN BUSINESS PARK SITE ................................................................. 265.1

Section objectives ................................................................................................................... 26

5.2 The site .................................................................................................................................... 265.3 Summary of our conclusions at the site assessment (stage 2a) stage ................................... 275.4 Treatment option for assessment ............................................................................................ 275.5 Key outcomes from the assessment ....................................................................................... 29

6 ASSESSMENT OF LEE VALLEY LEISURE COMPLEX GOLF COURSE (SOUTHERN PART)SITE ...................................................................................................................................................... 34

6.1 Section objectives ................................................................................................................... 346.2 The site .................................................................................................................................... 356.3 Summary of our conclusions at the site assessment (stage 2a) stage ................................... 366.4 Shortlist Option for assessment .............................................................................................. 366.5 Key outcomes from the assessment ....................................................................................... 36

7 ASSESSMENT OF ARDRA ROAD NORTH INDUSTRIAL SITE .................................................... 417.1 Section objectives ................................................................................................................... 417.2 The site .................................................................................................................................... 417.3 Summary of our conclusions at the site assessment (stage 2a) stage ................................... 427.4 Shortlist Option for assessment .............................................................................................. 427.5 Key outcomes from the assessment ....................................................................................... 43

8 ASSESSMENT OF LOWER HALL SITE ......................................................................................... 47


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8.1 Section objectives ................................................................................................................... 478.2 The site .................................................................................................................................... 488.3 Summary of our conclusions at the site assessment (stage 2a) stage ................................... 498.4 Shortlist Option for assessment .............................................................................................. 498.5 Key outcomes from the assessment ....................................................................................... 50

9 CONCLUSIONS AND IDENTIFICATION OF PREFERRED SITE .................................................. 549.1 Section objectives ................................................................................................................... 549.2 Conclusions on the Deephams Sewage Works site ................................................................ 549.3 Conclusions on the Meridian Business Park site .................................................................... 559.4 Conclusions on the Lee Valley Leisure Complex Golf Course (southern part) site................. 569.5 Conclusions on the Ardra Road site ........................................................................................ 569.6 Conclusions on the Lower Hall site ......................................................................................... 579.7 Identification of the preferred site ............................................................................................ 57

10NEXT STEPS .................................................................................................................................. 58


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List of Tables

Table 1: Stage 3 Criteria to inform the identification of preferred site ................................................... 12

List of FiguresFigure 1: Plan showing location of Deephams Sewage Works .............................................................. 7 Figure 2: The assessment methodology ................................................................................................. 8Figure 3: Plan of shortlist sites .............................................................................................................. 10Figure 4: Planning and environmental constraints - Deephams Sewage Works site ........................... 16Figure 5: Illustrative Deephams Conventional Activated Sludge plant layout ....................................... 18Figure 6: Illustrative Deephams IFAS / Conventional Activated Sludge layout ..................................... 19Figure 7: Illustrative Deephams MBR / Conventional Activated Sludge layout ..................................... 20Figure 8: Illustration of existing Deephams Sewage Works odour generation ..................................... 22 Figure 9: Illustration of potential odour generation from Deephams Sewage Works IFAS option ........ 23Figure 10: Indicative effluent quality timeline for Deephams conventional AS option ........................... 24Figure 11: Indicative effluent quality timeline for the Deephams 33% IFAS option .............................. 25Figure 12: Indicative effluent quality timeline for the Deephams 33% MBR option .............................. 25 Figure 13: Planning and environmental constraints - Meridian Business Park site .............................. 26Figure 14: Illustrative Meridian Business Park IFAS layout .................................................................. 28Figure 15: Illustrative layout for infrastructure required at Deephams Sewage Works site in association

with any of the off site development options ................................................................................ 29Figure 16: Illustrative plan of potential odour generation from Meridian Business Park site option ...... 33Figure 17: Indicative effluent quality timeline for the Meridian Business Park IFAS option .................. 34 Figure 18: Planning and environmental constraints - Lee Valley Leisure Complex Golf Course

(southern part) site ....................................................................................................................... 35Figure 19: Illustrative Lee Valley leisure Complex (Southern part) conventional AS layout ................. 37Figure 20: Illustrative plan of potential odour generation from Lee Valley Leisure Complex Golf Course

(southern part) site option ............................................................................................................ 40Figure 21: Indicative effluent quality timeline for the Lee Valley Leisure Complex Golf Course

(southern part) site conventional AS option ................................................................................. 41Figure 22: Planning and environmental constraints - Ardra Road site .................................................. 42Figure 23: Illustrative Ardra Road conventional AS layout .................................................................... 43Figure 24: Illustrative plan of potential odour generation from Ardra Road site option ......................... 46Figure 25: Indicative effluent quality timeline for the Ardra Road site conventional AS option ............. 47Figure 26: Planning and environmental constraints - Lower Hall site ................................................... 48Figure 27: Illustrative Lower Hall conventional AS layout ..................................................................... 49Figure 28: Illustrative plan of potential odour generation from Lower Hall site option .......................... 53Figure 29: Indicative effluent quality timeline for the Lower Hall site conventional AS option .............. 54


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1 Executive summary

1.1.1 Deephams Sewage Works, located in Enfield in north east London, is the ninth

largest sewage works in England. It treats sewage collected from within its catchmentand discharges treated effluent that flows into the Salmons Brook, a tributary of theRiver Lee, in accordance with a discharge consent set by the Environment Agency.

1.1.2 The Environment Agency has issued a new discharge consent that requires us tomake improvements to the quality of the discharge. The Deephams Sewage WorksUpgrade (the upgrade) will improve the quality of effluent (treated wastewater)discharged from the Deephams Sewage Works into the Salmons Brook. It will

accommodate growth within the catchment to at least 2031, and improveinfrastructure at the sewage works, much of which is now over 50 years old.

1.1.3 The upgrade has to be delivered whilst the existing sewage works remains

operational to treat the sewage to the existing consent levels. This places significantengineering constraints on our ability to implement the upgrade within the boundariesof the existing sewage works site. We have therefore considered the use of a numberof treatment technology options to deliver the upgrade both on the existing site, and

on a new site, within these engineering constraints.

1.1.4 This report documents the process that we have followed in assessing 5 shortlist

sites identified through the site assessment work undertaken in stage 2a of theproject. The report sets out how we have assessed the shortlist sites against relevantproperty/legal, planning, environmental and engineering issues that could affect thedelivery of the upgrade. The shortlist sites assessed were:

Deephams Sewage Works site

Meridian Business Park site

Lee Valley Leisure Complex Golf Course (southern part) site

Ardra Road North Industrial Area site

Lower Hall site

1.1.5 The conclusion of the report is that the Deephams Sewage Works site is thepreferred site for delivering the upgrade. The Deephams Sewage Works site has

significant advantages over the other shortlist sites and is the most appropriateoption.

1.1.6 This conclusion will be published as part of the phase 1 public consultation to test theconclusions that we have reached on the shortlist sites.

2 Introduction

2.1 Section objectives

2.1.1 This introduction explains the background to the Deephams Sewage Works upgrade,provides an overview of the assessment methodology process, and explains the

purpose and structure of this report.


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2.2 Background to the Deephams Sewage Works upgrade

2.2.1 Deephams Sewage Works is one of our six main sewage works that serve London. It

is located off Picketts Lock Lane in Edmonton, as shown in Figure 1 below. It is theninth largest sewage works in England and serves a population equivalent of 885,000

people (as of 2010). The catchment that Deephams Sewage Works serves extendsover large parts of north east London, and northwards beyond the M25.

Figure 1: Plan showing location of Deephams Sewage Works

2.2.2 Sewage treatment has been undertaken in this part of Edmonton since the 1870swhen the first Edmonton sewage farm was developed on adjoining land. The sewage

treatment works was largely constructed on the current site in the 1950s and 1960s.

2.2.3 Despite the various improvements over the last 30 to 40 years, and those under

construction, the current sewage works is predominately the works that was firstconstructed in the 1950s and 1960s. The ageing plant is under increasing pressure tomeet and maintain treatment standards.

2.3 Summary of the need for the upgrade

2.3.1 The need for the upgrade is set out in the National Policy Statement for Waste Water,and can be summarised as the requirement to respond to:

an increase in the discharge consent requirements

an increase in flow to the works:


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a requirement to provide sufficient treatment capacity to meet populationgrowth within the catchment already served by the works.

a requirement to respond and adapt to the challenges of climate change.

ageing infrastructure under pressure to meet and maintain treatment standards

2.3.2 The upgrade will also deliver wider social or environmental benefits, for examplereduced odour emissions and, depending on the option selected for implementation,increased renewable energy generation.

2.4 Summary of the Assessment Methodology

2.4.1 We have developed an assessment methodology for selecting the most appropriateoption for delivering the upgrade, including the assessment of site and treatment

technology options.

2.4.2 The methodology allows for the assessment of a range of strategies for meeting theneed for the upgrade. It allows for the consideration of potential locations for newsewage treatment infrastructure. The construction of the upgrade could be on theexisting site, although the site would have to remain operational throughout the

upgrade, or it could be on a new site nearby. A suitable treatment technology optionhas to be selected, to meet the treatment requirements of the new discharge consent

within funding, programme, treatment technology and physical site constraints.

2.4.3 The proposed methodology is a multi-stage process, with stages undertaken both inparallel and sequentially. Figure 2 below illustrates this process diagrammatically.

Figure 2: The assessment methodology


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2.4.4 The assessment process firstly allows an initial review of strategic options for meeting

the need for the upgrade to be undertaken. From this, an assessment of treatmentoptions is undertaken, alongside an assessment of potential development sites. Amore detailed assessment of a shortlist of sites is then undertaken to enable apreferred site to be identified. The preferred site is then published for a first phase of

public consultation and stakeholder engagement.

2.4.5 Alongside, and following on from, the first phase of consultation we will undertake

scheme design development work and further work on treatment options. This willconfirm the feasibility of our preferred site and treatment technology options fordelivering the upgrade. A second phase of public consultation will then be held on ourproposals and designs for the upgrade and information on the potential environmental

impacts of the upgrade and our plans for mitigating them. An application forpermission to build the upgrade will then be submitted.

2.4.6 An essential part of the methodology is an ongoing process of review and checkingthe validity of previous assessments through feedback loops at all stages of the

process. This enables the assessment of sites and options to remain valid asinformation changes and new information is obtained. Thus, where necessary, stages

in the process may be repeated (or back-checked) in order to take account of newinformation or other changes of circumstance.

2.5 Structure of this report

2.5.1 This report documents stage 3 of the assessment methodology process theidentification of the preferred site. Section 3 of this report outlines the shortlist sitesand how they were assessed against relevant property / legal issues planning,environmental, engineering and property/legal issues that could affect the upgrade.

2.5.2 Sections 4 to 8 explain the outcomes of the assessment process for each shortlistoption. Section 9 reports the conclusions of this assessment and identifies the

preferred site. Finally, section 10 describes the next steps with the project.

3 The identification and assessment of shortlist sites


3.1.1 This section provides a description of how the shortlist site options were identifiedand the process by which they were assessed.

3.2 Site assessment (stage 2a)

3.2.1 We identified a longlist of 22 potential sites, including the existing Deephams Sewage

Works site, for delivering the Upgrade to meet the new discharge consent standard.Following an assessment of these sites against property/legal, planning and

environmental, and engineering criteria, the shortlist sites (Identified in Figure 3) are:

Site 1 Deephams Sewage Works

Site 6 Meridian Business Park

Site 9 Lee Valley Leisure Complex Golf Course (Southern part)

Site 11 Ardra Road Industrial Area

Site 15 Lower Hall


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Figure 3: Plan of shortlist sites

3.2.2 Further information on the work that led to this shortlist is reported in the separate

Site assessment stage 2a report.

3.3 Treatment options assessment (Stage 2b)

3.3.1 As a separate stage of work, we considered a range of sewage treatmenttechnologies that could potentially meet the discharge consent standard. A number ofpotential treatment technologies were taken forward as a result of that assessmentprocess.

3.3.2 Further details of this assessment work are reported in the Treatment options

assessment stage 2b report. It should be noted that treatment processes will beconsidered further through our ongoing scheme design development work on theupgrade.

3.4 How the shortlist sites were assessed in stage 3

3.4.1 Preliminary design work was undertaken on each of the shortlist sites to enable theassessment work to be undertaken. This included the preparation of preliminary

layouts showing the extent of the built development and the preparation of potentialconstruction programmes. Due to their size or shape, some of the shortlisted sitesmay be capable of only accommodating a single treatment technology option,whereas others may be capable of accommodating a number of treatment options.


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3.4.2 The decision on the number of preliminary layouts that were prepared for each site

took account of the extent to which different treatment options were considered likelyto give rise to significantly different assessment results on the shortlisted sites thatmay affect the selection of a preferred site. On the Deephams Sewage Works site forexample, different treatment technology options could result in different development

areas being required, or construction programmes, as a result of the need to phasedevelopment alongside the existing operational works. On other sites where there

would not be a phasing requirement, the differences between treatment technologylayouts and programmes, and the impacts potentially arising from them, is morelimited. For these sites we have shown a layout for the treatment technology withthe largest footprint compatible with the site.

3.4.3 The assessment of each shortlisted site enabled preliminary conclusions to be drawnon the potential impacts arising from the development of the upgrade on each site.

Where the potential for significant differences between treatment technology optionson a shortlisted site were identified, these were highlighted. Sites were not eliminated

at this stage on the basis of the treatment technology that was assessed on the site.The options that we assessed are summarised below:

3.4.4 Three treatment options were assessed for the Deephams Sewage Works site atthe secondary treatment stage of the process:

Conventional activated sludge to treat all of the sewage

Integrated Fixed-film Activated Sludge (IFAS) to treat a third of the sewage andconventional activated sludge to treat the remaining two thirds

A Membrane Bio-Reactor (MBR) to treat a third of the sewage and conventional

activated sludge to treat the remaining two thirds

3.4.5 For the Meridian Business Park site we assessed Integrated Fixed-film Activated

Sludge (IFAS) a treatment technology that has the benefit of requiring a slightlysmaller footprint than Conventional Activated Sludge. Constraints on available spaceat the Meridian Business Park site meant that Conventional Activated Sludge couldnot be accommodated.

3.4.6 We assessed a Conventional Activated Sludge treatment process at the Lee ValleyLeisure Complex Golf Course (southern part) site. This is a more modern version

of the sewage treatment processes on the existing Deephams Sewage Works site.This is a resilient treatment process that has an established track record and is

proven on the scale required at Deephams.

3.4.7 We also assessed a Conventional Activated Sludge treatment process at the Ardra

Road site, and at the Lower Hall site.

3.4.8 Our selection of these treatment processes for use in the site assessment processdoes not mean that alternative treatment technologies will be excluded from furtherconsideration. We have not made any final decisions on the treatment technologies tobe used in the upgrade at this stage.

3.4.9 The options were subjected to an assessment against a range of property / legal,

planning and environment, and engineering key issues relating to the construction

and operation of the upgrade.


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3.4.10 These issues are drawn from a range of sources including issues that are key to the

project (e.g. energy consumption / site size / odour / land availability / cost), issuesthat are central to the use of land (e.g. planning designations / neighbouring landuses / access / site shape) and issues key to the likely receiving environment (e.g.nature conservation / amenity / water resources and flood risk / heritage).

3.4.11 These issues are linked to key criteria which form the basis against which each sitewould be assessed against each issue. The issues and their associated criteria are

prepared in an assessment matrix, divided by the different topics. The assessmentcriteria are identified in Table 1 below.

Table 1: Stage 3 Criteria to inform the identification of preferred site

CRITERION Basis for assessment

Property/legal criteria

Ownership of site andtenancies

Assessment of ownership and tenancy constraints to development

Estimated acquisition cost Assessment of potential acquisition costs

Crown land and special land Assessment of any legal procedures relating to special land

Lee Valley Regional ParkAuthority controlled land

Assessment of any legal procedures required under the 1966 Act

Assessment of likelihood ofneed for CompulsoryPurchase Order

Assessment of risk of needing to use a Compulsory PurchaseOrder to acquire land

Access and materialtransfer rights

Assessment of any legal issues relating to access or materialtransfer

Planning and environmental criteria

Planning application andconsents

Description of route to consent and consents required or theconstruction/operation of the option.

Assessment of planning history of site and constraints arising fromconsented or current applications, including conditions and legalagreements

Assessment of planning history of adjoining land and constraintsarising from consented or current applications, including conditionsand legal agreements

London Plan/UnitaryDevelopment Plans/LocalDevelopmentFrameworks/SupplementaryPlanning Documentsallocation or special policyareas

Assessment of compliance or conflict with specific land useallocations or planning objectives

Green Belt and MetropolitanOpen Land

Assessment against Green Belt and Metropolitan Open Landpolicy and guidance

Heritage designations Assessment of potential impacts on archaeological priority areas,Scheduled Monuments, Listed Buildings, Conservation Areas,

Historic Parks and Gardens, Local Site Register


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Landscape designations Assessment of potential effects on landscape, townscape, visual,gap or open space designations

Nature conservationdesignations

Assessment of potential effects on European site (SpecialProtection Areas, Special Areas of Conservation and Ramsarsites)

Assessment of potential effects on Sites of Special ScientificInterest

Assessment of potential effects on local nature conservation andbiodiversity designations

Assessment of potential effects on nature reserves

Assessment of potential effects on protected species

Water resources Assessment of potential effects on groundwater source protectionzones

Assessment of potential effects on surface water resources (flowand quality)

Sustainability Assessment of carbon emissions during construction (includingembodied carbon) and operation

Assessment of potential for renewable energy generation

Assessment of potential for climate change adaptation

Assessment of waste generation opportunities for wasteminimisation, reuse or recycling

Assessment of risk of contamination and scope of mitigation

Assessment of opportunities for reusing previously developed land

Assessment of opportunities for recreation enhancement

Assessment of opportunities for biodiversity enhancement

Transportation and access Rail connection practicability: availability/location of connectionand suitability of interconnecting access route

Water freight practicability: availability/location of connection andsuitability of interconnecting access route

Suitability of road/interconnecting road access: particularly forHeavy Goods Vehicles/abnormal indivisible loads

Sensitivity of access route

Assessment of potential impacts associated with operationaltransport and access

Community and amenityeffects/proximity to

sensitive receptors

Assessment of potential impacts on Lee Valley Regional Park,other recreational or sports sites, navigation and recreational

water use, public rights of way, permissive paths and accesssites, De facto or non-designated open space, and allotments


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Assessment of sensitivity to noise, dust, on-site constructionvehicle emissions and odour during construction

Assessment of sensitivity to odour, dust and noise effects duringoperation

Assessment of visual effects

Assessment of socio-economic and regeneration effects

Assessment of health considerations

Engineering criteria

Site size and shape Comparison to minimum/optimum size for the specific treatmentoption

Assessment of whether the shape and layout of the site constrainthe optimum layout for the treatment option

Construction duration, highlevel description ofconstruction phasing,

Description of construction duration and phasing (not assessedagainst specific criteria)

Heavy Goods Vehicle andLarge Goods Vehiclerouting, and level of trafficmovements

Description of routing and movements (not assessed againstspecific criteria)

Connectionfeasibility/location

Distance from Deephams/sewer interception

Infrastructure/structures between Deephams/sewer and site,including requirements to facilitate discharge of treated effluent tothe Salmons Brook and return of sludge to Deephams SewageWorks for treatment

Site features Above and below ground conditions (includingthird party assets)

Geology

Site levels

Other engineering considerations

Flood risk and scope formitigation Assessment against technical guidance to the National PlanningPolicy Framework

Site efficiency Ability to accommodate all requirements on-site (and if notdescribe how development can be achieved using a combinationof sites)

Ability to secure all required site services needed to facilitate thetechnology being assessed for development e.g. powersupply/communications/other

Potential for effects from development upon existing site oradjacent services e.g. power supply/communications/other

System engineering Process risk during construction


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requirements Effluent quality timeline (quality improvements in discharge overtime)

Odour generation duringoperation and scope formitigation

Assessment of potential odour generation and costs of mitigation

Whole life cost Assessment of whole life cost

Value for money Availability/likelihood of competitive tenders and risk ofimplementation of project to customers bills

3.4.12 We assessed each site against the criteria, using professional judgement, knowledgeand expertise to inform that assessment. The assessment is a qualitative descriptionof the options performance against the relevant criteria, serving as an indicator as to

the potential significance of a particular issue for the progression of a particular site.

3.4.13 The assessment was undertaken on the basis of the information available at the timeof the assessment between late 2011 and Spring 2012. We undertook a process of

review and analysis throughout the assessment to ensure that its conclusionsremained valid as any new information was generated or circumstances change.

3.4.14 Members of the Stakeholder Forum were engaged on the assessment criteria, both inforum meetings and in stakeholder workshops, during the site assessment process to

ensure that the approach being taken to the assessment of options was appropriate.For further information on the stakeholder forum, please refer to our Consultation

Strategy document.

3.4.15 The outcomes of our assessment of each of the shortlist sites is reported in the

following sections 4 to 8 of this report.

4 Assessment of Deephams Sewage Works site


4.1.1 This section describes the assessment of the Deephams Sewage Works site.

4.2 The site

4.2.1 The 35 hectares existing Deephams Sewage Works site is located to the west of theWilliam Girling Reservoir (A) and is bordered by the A1055 (Meridian Way) to thewest, beyond which lies a railway line and then an area of residential development

(B). Another small area of housing (C) lies immediately north of the site, beyondwhich lies Picketts Lock Lane and then the Lee Valley Leisure Complex (D). PickettsLock Lane runs into Lee Park Way which together form part of the northern andeastern boundaries of the site respectively. A builders merchants site, highways

maintenance depot and car park (E) are located further to the north-east and east ofthe site and the Ardra Road Industrial Estate (site 11) is situated immediately to the

south.

4.2.2 The planning and environmental constraints for the site are identified in Figure 4below.


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Figure 4: Planning and environmental constraints - Deephams Sewage Works site

4.3 Summary of our conclusions at the site assessment (stage 2a) stage

4.3.1 Our site assessment (stage 2a) conclusions on the Deephams Sewage Works site

was that the site had fewer property / legal, planning and environmental constraintsthan the other longlist sites. The delivery of the upgrade on this site was assessed as

representing a major challenge in engineering terms due to the lack of spare land andthe need to retain a fully operational sewage works throughout the upgrade.

However, we concluded that if those engineering constraints could be overcome andan upgrade scheme designed that was acceptable in planning and environmental

terms, within the environmental and financial constraints imposed by the regulatorsand at an acceptable level of treatment process risk to us, then the Deephams

Sewage works site would be an appropriate location for the upgrade.

4.4 Treatment options for assessment

4.4.1 The treatment technology options used as the basis for the assessment of theDeephams Sewage Works site are:

Conventional Activated Sludge (AS) treatment to treat all of the sewage

Integrated Fixed-film Activated Sludge (IFAS) treatment to treat a third of thesewage and conventional Activated Sludge (AS) to treat the remaining two thirds


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A Membrane Bio-Reactor (MBR) to treat a third of the sewage and conventionalActivated Sludge (AS) to treat the remaining two thirds

4.4.2 The options are illustrated in figures 5, 6 and 7 on the following pages.

4.5 Key outcomes from the assessment

4.5.1 The assessment of the Deephams Sewage Works site resulted in the following keyoutcomes. Many of the outcomes are the same for the 3 treatment technology

options, however where they significantly differ this is identified in the report.

Property/Legal issues

4.5.2 The site presents a good opportunity for the development of the upgrade in propertyterms as the land is our ownership. It is anticipated that there will be a need for an off-

site construction compound during the Upgrade build process, however this could beaccommodated on land we own at Lower Hall (site 15) to the south of William Girling

Reservoir.

Planning and Environmental Issues

4.5.3 Development of the Upgrade on this site will require an application for planningpermission to be submitted to the London Borough of Enfield. The site is an existing

sewage works and the use of this site for the Upgrade will not conflict with the existinguse, nor with any specific land use planning designations. The site lies within thewider Central Leeside Area Action Plan area, proposals for which are currently inpreparation by LB Enfield, and the Council is supportive of the principle of upgradingthe existing sewage works.

4.5.4 The Deephams Sewage Works site lies outside the Green Belt and Lee ValleyRegional Park (LVRP). Land at Lower Hall which could be used for a temporaryconstruction compound lies within the Green Belt and LVRP. The need for thecompound will have to be justified as part of the planning application in order to meetthe requirements of national guidance and development plan policy. We consider thatwe will be able to demonstrate a need for the compound should it be required, and

that the temporary use of that site, coupled with the implementation of a restorationscheme and long term appropriate after-use would be shown to be acceptable inplanning terms.

4.5.5 The initial layout plans for the three options at Deephams identify that there is the

potential for loss of some of the mature wooded bund forming the eastern siteboundary as well as some mature woodland along the north western and north

eastern boundaries as part of the Upgrade. Mitigation for this would need to beprovided, involving replacement planting of the boundary edges to the northwest,

northeast and east.


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Figure 5: Illustrative Deephams Conventional Activated Sludge plant layout


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Figure 6: Illustrative Deephams IFAS / Conventional Activated Sludge layout


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Figure 7: Illustrative Deephams MBR / Conventional Activated Sludge layout

4.5.6 Part of this area is within the Lee Valley Site of Metropolitan Importance for NatureConservation (SMINC). Mitigation of impacts on the SMINC will require compensatorymeasures that will provide, at worst, no net loss of biodiversity value or, at best, a netgain in biodiversity. This could be delivered by like for like habitat creation within or

adjacent to the existing site, with Lower Hall providing a potentially suitable offsite

location, or through habitat enhancement of the existing site.


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4.5.7 Potential environmental effects upon the Chingford Reservoirs SSSI are likely to be

restricted to impacts of disturbance upon birds, as the boundary of the Deephams siteis approximately 100m from the edge of the SSSI. The potential effect of disturbanceupon bird species utilising the SSSI is likely to be low as the reservoirs are at anelevated level compared to that of the development site and, due to the size of the

SSSI, there is ample habitat into which the birds can relocate following disturbance.On site, there is the potential for impacts through disturbance and loss of habitat

which could affect common breeding birds, bats, reptiles and invertebrates, for whichmitigation would need to be provided.

4.5.8 There is the risk of potential impacts on groundwater and surfacewater duringconstruction and operation of the Upgrade, although these risks are considered

capable of mitigation with normal good practice construction techniques and ournormal operational management procedures. There would be the need to divert a

drainage ditch within the northern part of the Deephams Sewage Works site toaccommodate the upgraded works, although this could be achieved without impacts

on flood risk and with only temporary ecological and physical disruption to habitatspending its reinstatement in its new location. Should it prove necessary to incorporate

flood mitigation as part of the upgrade then there is some limited space available onsite. Once the phased implementation of the Upgrade is underway, there will be apositive impact on water quality in the Salmons Brook, increasing as each phase ofthe upgrade is implemented.

4.5.9 Road access to the site is very good with the site located in close proximity to theA1055. Access is gained via a traffic light junction into Picketts Lock Lane. Access tothe site will involve two sharp turns, and could possibly constrain delivery of abnormalor indivisible loads (AILs). Outside peak hour material delivery times may be imposed

by LB Enfield / TfL, and appropriate routing will need to be identified and mitigation

provided if required. Construction traffic should be routed away from residentialareas to avoid emissions, severance, accident risk, fear and intimidation problems.There is the potential to consider the use of water freight transport for someconstruction materials or items, pending detailed examination of the constraints withinthe Lee Navigation. Travel planning will also be required and initiatives implemented,

including ensuring ease of access for staff / workers to/from nearest rail station.

4.5.10 Construction activities are likely to cause some temporary disruption to recreationalusers of the LVRP. These impacts would principally be on users of public rights ofway (PRoW) immediately adjacent to the site, particularly along Picketts Lock Lane,

including the Pymmes Brook Trail, to the north, and along Lee Park Way to the east,which is used as a footpath and includes a cycle route. It is also possible that users

of surrounding PRoW, including users of the Lee Valley Walk, Lee Valley Pathwayand Lee Valley Cycle Route may be affected by noise, dust and odour emissions andby visual impacts and increased traffic associated with construction activities. Thereis the potential for temporary noise impacts on the southern part of the Lee Valley

Leisure Complex and Athletics Centre. However, all these impacts would betemporary and short term and would be mitigated through implementation of aConstruction Environmental Management Plan (CEMP).

4.5.11 Potential impacts on the local community, including nearby sensitive receptors, arepredicted to arise during construction including from noise, dust, traffic and odour.

The extension of the Sewage Works closer to the northern boundary of the site couldresult in impacts to residents along Picketts Lock Lane, but mitigation, such as

retention of trees and additional tree planting around the periphery of the site, mayassist in reducing these.


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4.5.12 The highest levels of construction noise would usually occur during demolition, site

clearance, earthworks and piling activities, impacting on residential properties inPicketts Lock Lane, Hudson Way, Prespa Close, Volta Close and Badma Close(within 100m) and minor impacts in Dunnock Close and Lee Valley Golf Course(within 150m).

4.5.13 Construction traffic could cause disturbance to residential receptors although the useof Meridian Way should not cause significant noise increases as this is already a

busy commercial route. Dust impacts are likely to occur, however residentialproperties are unlikely to be significantly adversely affected as smaller airborneparticles are likely to settle out within approximately 100m of the site. Odour couldarise during demolition of the disused digesters in the north west corner of the site,

however this would be mitigated by controlled removal of any residual organicmaterials prior to demolition. Our contractors would work to a CEMP which should

ensure that residual construction noise and air quality impacts are generally negligiblebut no more than minor to moderate at the closest receptors.

4.5.14 During operation of the upgraded works, operational noise would be typically lessthan existing baseline noise levels during the daytime. At night there may be some

audibility of the operational noise at receptors located at less than 100m from the site,but the impact would be no more than minor. Through the detailed design of thescheme it should be possible to reduce operational noise to be of negligible impact byappropriate design of buildings housing noisy plant, achieved by screening and

enclosures or through sound insulation. Dust emissions during operation would notbe expected to be significant.

4.5.15 Figure 8 below illustrates how odour from the sewage works currently leaves theexisting Deephams Sewage Works site and affects the surrounding area. The red

area of the map is where the odour is strongest and the yellow area is where it isweakest.

Figure 8: Illustration of existing Deephams Sewage Works odour generation


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4.5.16 The upgraded works will include odour controls to a standard to be agreed with LB

Enfield through the planning application process. These, coupled with implementationof an Odour Management Plan for the site will result in a reduction in odourexperienced from the site. Initial modelling works have been completed for theproposals, with the covering of the primary settlement tanks (PSTs) and secondary

digesters as part of the odour mitigation strategy. In this scenario, using the IFAStechnology option as an example, approximately 290 properties would be within the

5ouE/m3 contour (the majority of recorded complaints about odour from the existing

Deephams Sewage Works site originate within this 5ouE/m3 area), as shown in Figure

9 below. Different treatment technologies could result in minor changes to the numberof properties affected.

Figure 9: Illustration of potential odour generation from Deephams Sewage Works IFASoption

4.5.17 Compared to other sites, the development of the upgrade on the Deephams SewageWorks site would have lower carbon emissions during construction and operation

because all treatment remains on site and there is no requirement for pipelinematerials and pumping energy to transfer sewage to and from another site.

Engineering Issues

4.5.18 The site is large enough to accommodate any of the three secondary treatment

technology options (conventional AS, IFAS and MBR) used as the basis of theassessment. When comparing the three options, the two phase Conventional AS

treatment process layout requires revised process loads to allow a smaller footprint

layout to be designed. The partial IFAS and MBR options could offer advantages interms of reducing the footprint of the construction works.


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4.5.19 The need to maintain the existing works functioning throughout dictates the layout for

each of the options as the first phase of construction works has to take place outsideof existing streams A, B and C which need to remain in operation until a new streamis commissioned. This results in a need for development to take place on the site ofthe old digesters (disused) in the north west corner of the site, and also in areas close

to the northern and north eastern boundaries between the site and Picketts LockLane/Lee Park Way. This would bring new development closer to housing located on

Picketts Lock Lane.

4.5.20 We tested the speed at which the 3 treatment options could potentially be developedon the Deephams Sewage Works site, and the potential phasing of the improvementsin treated effluent quality that they would deliver.

4.5.21 Construction of the conventional AS based technology option is assumed to last untilJanuary 2020. The construction would proceed as a 2 phase construction project,

requiring the installation of temporary IFAS units in the existing B&C stream AS tanks.These would subsequently be removed as these phases are themselves

redeveloped. It would also be necessary to reduce the peak flow treated by the worksfrom the current 443 Ml/d to approximately 370 Ml/d, in agreement with the

Environment Agency. This option would deliver a series of staged improvements ineffluent quality as indicated in Figure 10 below.

Figure 10: Indicative effluent quality timeline for Deephams conventional AS option

4.5.22 We consider the conventional AS treatment process to be reliable and to be provenon this scale (it is the current treatment process at Deephams). However, there maybe a need for revised process designs to accommodate the two phase upgrade onthis site. These would need to be verified with contractors to ensure that they can be

delivered. It is considered likely that multiple competitive tenders would be receivedfor the project and that value for money to our customers could be achieved.

4.5.23 Construction of the 33% IFAS based technology option on the Deephams SewageWorks site is assumed to last until April 2021. This option would deliver staged

improvements in treated effluent quality as indicated in Figure 11 below.

50% AS

ConstructionFinish

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Figure 11: Indicative effluent quality timeline for the Deephams 33% IFAS option

4.5.24 The IFAS technology is not widely used on the scale envisaged for Deephams and

there are only a limited number of suppliers of the IFAS variants that we considerrepresent proven technology. Nevertheless, the IFAS component of the project is not

a major part of the overall cost and we consider that value for money to ourcustomers could be achieved through a competitive tendering process.

4.5.25 Construction of the 33% MBR based technology option on the Deephams SewageWorks site is assumed to last until April 2021. The construction would proceed as a 3phase construction project. This option would deliver staged improvements in treatedeffluent quality as indicated in Figure 12 below. The installation of the 33% MBR plant

and disc filters early in the programme would deliver significant benefits early in theconstruction programme.

Figure 12: Indicative effluent quality timeline for the Deephams 33% MBR option

4.5.26 The MBR technology is not widely used on the scale envisaged for Deephams andwe consider that there are therefore process risks for us associated with this option.

We consider that value for money to our customers could be achieved through acompetitive tendering process.

RGF

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Conclusions on the Deephams Sewage Works site

4.5.27 The conclusions on the Deephams Sewage Works site are reported in section 9.2 ofthis report.

5 Assessment of Meridian Business Park site


5.1.1 This section describes the assessment of the Meridian Business Park site.

5.2 The site

5.2.1 This site is approximately 14 hectares in size and comprises existing and vacantemployment land in mixed industrial uses. The site is located to the west of theWilliam Girling Reservoir (A). The A1055 (Meridian Way) lies to the west of the site,

beyond which is the railway and Woodall Road Industrial Area (Site 5). Residentialareas (B) lie further to the west beyond the A1055 and Site 5. There is a Flour Mill

and open space (C) to the north and open space (D) to the south in the Lee ValleyRegional Park. The Lee Navigation forms the eastern boundary.

5.2.2 The planning and environmental constraints for the site are identified in Figure 13below.

Figure 13: Planning and environmental constraints - Meridian Business Park site


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5.3.1 Our site assessment (stage 2a) conclusion was that of all the 12 industrial sites on

the longlist, this site, together with Ardra Road (Site 11) were assessed by us asbeing the industrial sites with the most potential for accommodating the upgrade. We

concluded that both sites should become shortlist sites, enabling their developmentpotential for the upgrade to be assessed in more detail. This more detailed

assessment needed to include further consideration of issues relating to landacquisition, flood risk, and issues relating to the loss of employment opportunities asa priority.

5.4 Treatment option for assessment

5.4.1 The treatment technology option used as the basis for the assessment of theMeridian Business Park site is Integrated Fixed-film Activated Sludge (IFAS). Thistreatment technology has the benefit of requiring a slightly smaller footprint than

Conventional Activated Sludge. Constraints on available space at the MeridianBusiness Park site meant that Conventional Activated Sludge could not be

accommodated.

5.4.2 An illustrative layout for the infrastructure that would need to be built at the Meridian

Business Park site as part of this option is shown in Figure 14 on the following page.Figure 15, below that, identifies the infrastructure that would need to be built at

Deephams Sewage Works as part of this option.


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Figure 14: Illustrative Meridian Business Park IFAS layout


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Figure 15: Illustrative layout for infrastructure required at Deephams Sewage Works site inassociation with any of the off site development options



5.5.1 The Meridian Business Park site is in multiple ownerships with in excess of 20

individual land interests identified. Parts of the site are in active employment use.Other areas have planning consent for redevelopment, with large parts of the site

cleared ready for future redevelopment. The existing industrial use, together withcurrent and potential future planning consents for employment development indicatethat the site would be expected to have high land acquisition costs. There isconsidered to be a high risk that a Compulsory Purchase Order may be required,

although this can be applied for as part of an application for a Development ConsentOrder.


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5.5.2 The site does not include any crown or special land and therefore aside from the

potential need for a Compulsory Purchase Order it is not considered that there areadditional legal complexities relating to land acquisition. A small part of the site lieswithin the Lee Valley Regional Park (LVRP), although this land is allocated asStrategic Industrial Land and is currently in industrial use. It is not considered that the

designation of that small part of land would lead to additional constraints to thedevelopment of the site, given its current use.


5.5.3 Development of the Upgrade on this site will require an application for DevelopmentConsent to be submitted to the National Infrastructure Directorate of the PlanningInspectorate under the Planning Act 2008.

5.5.4 The site comprises the entire Meridian Business Park, together with adjoiningemployment uses to the north. The site is occupied by several users, although large

areas of the site formerly occupied by Aesica Pharmaceuticals have been cleared

pending redevelopment for employment uses. Planning permission exists forwarehousing units on the eastern part of the site, one of which has been constructedand is operational. Pre-application discussions with London Borough of Enfield (LB

Enfield) are taking place about the future employment redevelopment of large parts ofthe site.

5.5.5 The site is a safeguarded Strategic Industrial Location (SIL) promoted by the LondonPlan policy 2.17 and implemented by the LB Enfield Core Strategy Policy 14.

Paragraph 2.79 of the London Plan explains that utility developments (such assewage treatment) would be suitable uses of SIL. Although not a policy requirement,LBE policy interpretation suggests that use of SIL for utilities development would onlybe acceptable if compensation SIL is provided to overcome any loss of SIL land.

Whilst utility development on SIL does not conflict with London Plan Policy, LondonBorough of Enfield has raised significant concerns about potential loss of employment

opportunities through the redevelopment of SIL sites for the Deephams SewageWorks upgrade.

5.5.6 The site also falls within the designated LB Enfield Core Strategy Ponders End PlaceShaping Priority Area (PEPSPA). Core policy 41 explains that the PEPSPA will seekto create new homes, development, employment, public realm improvements,

community facilities, leisure access and flood storage. The retention of employmentopportunities is identified as a particular objective of the policy. The inclusion of thesite within the PEPSPA raises additional policy conflicts given the planned

regeneration within the area around the site, particularly to the north and west,including the introduction of additional residential and leisure uses. If the site were tobe developed for the upgrade then there would be a specific conflict with the

PEPSPA objective of retaining and promoting employment opportunities within thelocal area.

5.5.7 The Meridian Business Park site is not located within the Green Belt and the majorityof the site lies outside the LVRP. However the Green Belt and Regional Park adjoins

the site to the south and east. Development within the boundaries of the site wouldavoid direct impacts on the Green Belt and Regional Park. However, there is the

potential for development on the site to indirectly affect the Green Belt and RegionalPark designation through indirect impacts relating to odour, noise, dust and visual

impacts.


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5.5.8 The design of the scheme will need to take account of any potential visual impacts on

recreational users within the green belt and Regional Park, and on the openness ofthe Green Belt. In terms of recreational uses, the Lee Valley Leisure Complex GolfCourse is a key recreational asset, lying immediate south of the Meridian BusinessPark site.

5.5.9 The sites landscape context is formed by heavily modified landscape elementsincluding transport and water/utilities infrastructure considered to be of low sensitivity.

Redevelopment of the Meridian site (existing industrial estate) would not materiallychange this wider landscape character. Due to the largely open site boundary withthe LVRP, construction and operational impact would also affect wider perceptuallandscape character. The layout plan for the Option identifies that there is very

limited space at the eastern boundary to accommodate structural landscaping tomitigate these impacts.

5.5.10 Space for mitigation at the northern boundary, to screen the development from thePonders End Mills Conservation Area, is also limited and potential impacts on this

Conservation Area and listed buildings would need further detailed assessment aspart of preparing the detailed design for the option. The site also lies within the LB

Enfield Area of Archaeological Importance and the impact of the development of theUpgrade on this unknown archaeological resource would have to be established.There are similar archaeological risks relating to the implementation of a pipelinetransfer from this site to the Deephams Sewage Works site, across the Lee Valley

Leisure Complex Golf Course.

5.5.11 Potential environmental effects upon the Chingford Reservoirs SSSI are likely to berestricted to impacts of disturbance upon birds, as the boundary of the site isapproximately 100m from the SSSI. The potential effect of disturbance upon bird

species utilising the SSSI is likely to be low as the reservoirs are at an elevated levelcompared to that of the development site and, due to the size of the SSSI, there is

ample habitat into which the birds can relocate following disturbance.

5.5.12 The Lee Valley SMINC is located adjacent to the Meridian Business Park site with nophysical barriers between the site and the SMINC. Potential environmental effectsupon the SMINC are unlikely as although the SMINC falls within the Meridian

Business Park site boundary, this area is already developed and works at theDeephams site are contained within the existing developed area. The proposedpipeline connection will require disturbance of vegetation within the northern part ofthe Lea Valley Golf Course around its waterbody. This area forms part of the SMINC.The use of the waterbody by great crested newts is unknown and this would need to

be investigated as the transfer pipeline passes in close proximity. There is also thepotential for impacts through disturbance and loss of habitat on common breedingbirds, bats, reptiles and invertebrates, for which mitigation would need to be provided.

5.5.13 There is the risk of potential impacts on groundwater and surfacewater duringconstruction and operation of the Upgrade, although these risks are consideredcapable of mitigation with normal good practice construction techniques and our

normal operational management procedures. The assessment work identifies that itmay be necessary to incorporate flood mitigation as part of the upgrade and there is

some limited space available to incorporate this on site. Once the implementation ofthe upgrade is completed on the Meridian Business Park site there will be a positive

impact on water quality in the Salmons Brook.


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5.5.14 Access to the site from the A1055 (Meridian Way) is via Morson Road. Access to the

site will involve a sharp turn on to Morson Road off the A1055, which could possiblyconstrain delivery of abnormal or indivisible loads (AILs). Outside peak hour materialdelivery times may be imposed by LB Enfield / TfL, and appropriate routing will needto be identified and mitigation provided if required. Construction traffic should be

routed away from residential areas to avoid emissions, severance, accident risk, fearand intimidation problems. There is the potential to consider the use of water freight

transport for some construction materials or items, pending detailed examination ofthe constraints within the Lee Navigation. Travel planning will also be required andinitiatives implemented, including ensuring ease of access for staff / workers to/fromnearest rail station.

5.5.15 Construction activities are likely to cause some temporary disruption to recreationalusers of the LVRP. These impacts would principally be on users of public rights of

way (PRoW) immediately adjacent to the site, particularly along the Lee Valley Walk,Lee Valley Pathway and Lee Valley Cycle Route. Users may be affected by noise,

dust and odour emissions and by visual impacts and increased traffic associated withconstruction activities. There is the potential for temporary noise impacts on the

northern part of the Lee Valley Leisure Complex golf course.

5.5.16 Potential impacts on the local community, including nearby sensitive receptors, arepredicted to arise during construction including from noise, dust, traffic and odour.The nearest sensitive receptors are at the high rise residential developments on Alma

Road at a distances of approximately 175m and 200m. Others include furtherresidential properties on Alma Road and Sandhurst Road at 250 to 300m. The LeeValley Golf course is located at a distance of 200m to the south of the site, and theLee Valley Camping and Caravan Park at a distance of approximately 500m.

5.5.17 The highest levels of construction noise would usually occur during demolition, siteclearance, earthworks and piling activities, impacting on residential properties to the

north of the site and beyond the A1055 and railway line at Ponders End, including theAcademy school that is under construction. There are likely also to be impacts onvisitors/users of Lee Valley Camping and Caravan Park and Lee Valley Leisure andGolf course during construction of the pipeline connections. However, all these

impacts would be temporary and short term and would be mitigated throughimplementation of a CEMP.

5.5.18 Construction traffic could cause disturbance to residential receptors although the useof Meridian Way should not cause significant noise increases as this is already abusy commercial route. Dust impacts are likely to occur, however residential

properties are unlikely to be significantly adversely affected as smaller airborneparticles are likely to settle out within approximately 100m of the site. Our contractorswould work to a Construction Environmental Management Plan (CEMP) which shouldensure that residual construction noise and air quality impacts are generally negligiblebut no more than minor to moderate at the closest receptors.

5.5.19 Through the detailed design of the scheme it should be possible to reduce

operational noise to be of negligible impact by appropriate design of buildingshousing noisy plant, achieved by screening and enclosures or through sound

insulation. Dust emissions during operation would not be expected to be significant.


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5.5.20 The development of the Meridian Business Park option will introduce a new odour

source into this location. The development of the upgrade at Meridian Business Parkwill require the design and implementation of odour controls to a standard to beagreed with LB Enfield as part of the preparation of the Development Consent Orderapplication. These, coupled with implementation of an Odour Management Plan for

the site will need to result in no significant odour impacts from the site. Initialmodelling works have been completed for the proposals, with the covering of the

primary settlement tanks (PSTs) on the Meridian Business Park site, and secondarydigesters on the Deephams Sewage Works site, as part of the odour mitigationstrategy. In this scenario, approximately 250 properties are within the 5ouE/m3contour (the majority of recorded complaints about odour from the existing Deephams

Sewage Works site originate within this 5ouE/m3 area), as shown in Figure 16 below.

Different treatment technologies could result in minor changes to the number of

properties affected.

Figure 16: Illustrative plan of potential odour generation from Meridian Business Parksite option

5.5.21 The Meridian Business Park site has higher carbon emissions during construction

and operation than the Deephams site as there is a requirement for pipeline materialsand pumping energy to transfer sewage to and from the Deephams Sewage Works

site.


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Engineering Issues

5.5.22 The size of the site is only just large enough to accommodate the IFAS treatmentprocesses, themselves being a reduced footprint than conventional AS processes.The layout for the Option highlights that further work will be required in consultation

with contractors to refine the proposals to allow for necessary separation between thedevelopment and the Lee Navigation and Wharf Road.

5.5.23 Construction of the Meridian Business Park IFAS Option is assumed to last until

February 2021. The construction would proceed as a single phase constructionproject, once the land has been acquired and existing occupiers and users have beenrelocated off site. This relocation results in a delayed construction start date. Theimprovements in treated effluent quality that would be delivered as a result of the

implementation of the option are indicated in Figure 17 below.

Figure 17: Indicative effluent quality timeline for the Meridian Business Park IFAS

option

5.5.24 The IFAS technology is not widely used on the scale envisaged for Deephams andthere are only a limited number of suppliers of the IFAS variants that we consider torepresent proven technology. Nevertheless, we consider that value for money to ourcustomers could be achieved through a competitive tendering process.

Conclusions on Meridian Business Park site

5.5.25 The conclusions on the Meridian Business Park site are reported in section 9.3 of thisreport.

6 Assessment of Lee Valley Leisure Complex Golf Course(southern part) site


6.1.1 This section describes the assessment of the Lee Valley Leisure Complex GolfCourse (southern part) site.

RGFBuilt

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6.2 The site

6.2.1 This is a 23 hectare site forming part of the wider Lee Valley Leisure Complex. The

existing uses on this site include part of the wider golf course, and the camp site andrelated car park. The wider leisure complex includes the remainder of the golf course,

together with a cinema, indoor bowls, indoor and outdoor athletics and large areas ofcar parking.

6.2.2 The site is located to the north of Deephams sewage works (site 1), west of the

William Girling Reservoir (A). It is bound by the A1055 (Meridian Way) to the westwith residential areas (B) located further beyond the A1055, and also immediately tothe south. Open space (C) located to the north is part of the existing LeisureComplex. Picketts Lock Lane (D) forms the southern boundary and the LeeNavigation (E) its eastern boundary, beyond which lies the William Girling Reservoir.

A builders merchants (F) is located adjacent to the south east corner of the site and a

disused industrial/warehousing unit (formerly occupied by Coca Cola) (G) to the southwest. Meridian Business Park (Site 6) is situated further to the north, beyond the golfcourse.

6.2.3 The planning and environmental constraints for the site are identified in Figure 18

below.

Figure 18: Planning and environmental constraints - Lee Valley Leisure Complex GolfCourse (southern part) site


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6.3.1 Our site assessment (stage 2a) conclusions on this site was that it was considered to

represent a good opportunity to accommodate the upgrade in engineering terms,given its close proximity to the Deephams Sewage Works site. However, the site was

assessed as having significant and complex land acquisition risks given that it is inpublic ownership by the Lee Valley Regional Park Authority and the Authority has

indicated that the site would not be made available for the upgrade. Notwithstandingthe land acquisition risks and complexities, given the close proximity of the site andthe relative lack of engineering constraints, we concluded that this site shouldbecome a shortlist site. Further assessment of the land acquisition issues needed tobe undertaken, and formal (written) confirmation of the Lee Valley Regional Park

Authoritys position on the future of the site secured and assessed.

6.4 Shortlist Option for assessment

6.4.1 The treatment technology option used as the basis for the assessment of the site is amore modern version of the sewage treatment processes on the existing Deephams

Sewage Works site Conventional Activated Sludge treatment process. This processis robust and resilient, has an established track record and is proven on the scale

required at Deephams.

6.4.2 An illustrative layout for the infrastructure that would need to be built at the Lee Valley

Leisure Complex Golf Course (southern part) site as part of this option is shown inFigure 19 below. Figure 15 above identifies the infrastructure that would need to bebuilt at Deephams Sewage Works as part of this option.



6.5.1 The Lee Valley Leisure Complex Site is owned by the Lee Valley Regional ParkAuthority (LVRPA) which has statutory responsibility for the planning and

management of the Regional Park. The site is in active use for recreation and openspace uses, and the adjoining land includes the nationally and regionally significant

Lee Valley Athletics Centre.

6.5.2 The LVRPA has clearly stated in writing that the site is not available for use to deliver

the upgrade, and that it would strongly resist any attempts made to acquire the landcompulsorily. It considers that there would be significant local, regional and national

support for its opposition to the use of the site for the upgrade.

6.5.3 Whilst a compulsory purchase order may be applied for as part of an application for aDevelopment Consent Order, the open space use of the site, and LVRPA ownershipbring additional complexities, including the need for special parliamentary procedures

to also be followed to acquire control of the land. Land owned by the LVRPA hasspecial protection under the terms of the Lee Valley Regional Park Act 1966. Our

assessment is that a Compulsory Purchase Order and further legal procedures wouldneed to be followed to acquire the site. As a result, we have assessed the land

acquisition risks as complex with the likelihood these could delay or frustrate thedevelopment of the upgrade on this site.


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Figure 19: Illustrative Lee Valley leisure Complex (Southern part) conventional ASlayout

6.5.4 Given the landowners strongly stated position, and the legal position with acquisitionof open space and land owned by the LVRPA, it is not possible to conclude that thesite could be successfully acquired.


6.5.5 Development of the upgrade on this site will require an application for DevelopmentConsent to be submitted to the National Infrastructure Directorate of the Planning

Inspectorate under the Planning Act 2008.

6.5.6 The site comprises the southern part of the Lee Valley Leisure Complex Golf Course,

including a campsite. The site is protected from non open space or recreationaldevelopments by national guidance and by a number of development plan policies.

6.5.7 The site lies wholly within the Green Belt and also within the LVRP. It is also

designated as public open space. The development of the upgrade on this site wouldconflict with relevant national guidance and development plan policy.


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6.5.8 In addition to direct impacts on the Green Belt, Regional Park and open space, there

would also be indirect impacts on the wider Green Belt and Regional Parkdesignation through impacts relating to odour, noise, dust and visual impacts. Thedesign of the scheme would also need to take account of visual impacts onrecreational users within the Green Belt and Regional Park, and on the openness of

the green belt. The Lee Valley Athletics Centre immediately to the west of the site is akey recreational asset, that could be materially affected by the development of the

upgrade on this site.

6.5.9 Potential environmental effects upon the Chingford Reservoirs SSSI are likely to berestricted to impacts of disturbance upon birds, as the boundary of the site isapproximately 80m from the SSSI. The potential effect of disturbance upon bird

species utilising the SSSI is likely to be low as the reservoirs are at an elevated levelcompared to that of the development site and, due to the size of the SSSI, there is

ample habitat into which the birds can relocate following disturbance.

6.5.10 No habitat loss from the Lee Valley SMINC is considered likely with the proposed

development as the boundaries of the proposal do not encroach into it. Mitigationmeasures to control the impacts of disturbance upon the Lee Valley SMINC should

be incorporated to ensure encroachment of works beyond the site does not occur, forexample through the erection of screening and/or barrier fencing. There is also thepotential for impacts through disturbance and loss of habitat on site which could affectcommon breeding birds, bats, reptiles and invertebrates, for which mitigation would

need to be provided. The site lies within the LB Enfield Area of ArchaeologicalImportance and the impact of the development of the Upgrade on this unknownarchaeological resource would have to be established.

6.5.11 There is the risk of potential impacts on groundwater and surfacewater during

construction and operation of the Upgrade, although these risks are consideredcapable of mitigation with normal good practice construction techniques and our

normal operational management procedures. Our assessment work identifies thatparts of the site fall within Flood Zone 2 and the upgrade would need to avoiddeveloping within these areas or provide flood mitigation as part of the upgradescheme. Once the implementation of the upgrade is completed on this site, there will

be a positive impact on water quality in the Salmons Brook.

6.5.12 Good access to the site is available either from the A1055 (Meridian Way) or fromPicketts Lock Lane. Outside peak hour material delivery times may be imposed by LBEnfield / TfL, and appropriate routing will need to be identified and mitigation providedif required. Construction traffic should be routed away from residential areas to avoid

emissions, severance, accident risk, fear and intimidation problems. There is thepotential to consider the use of water freight transport for some construction materialsor items, pending detailed examination of the constraints within the Lee Navigation.Travel planning will also be required and initiatives implemented, including ensuringease of access for staff / workers to/from nearest rail station.

6.5.13 Construction activities are likely to cause some temporary disruption to recreational

users of the LVRP. These impacts would be on users of facilities within the LeeValley Leisure Complex and the public rights of way (PRoW) immediately adjacent to

the site, particularly along the Lee Valley Walk, Lee Valley Pathway and Lee ValleyCycle Route. Users may be affected by noise, dust and odour emissions and by

visual impacts and increased traffic associated with construction activities.


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P1 A630 Identification of preferred site stage 3 report (public consultation ve