Wetlands Delivering Catchment Management …...Creation of pool/riffle sequence, varied depth, flow and depth deflectors etcdeflectors etc Woody debris reintroduction Incorporate woody

Wetlands Delivering Catchment Management Objectives

Matthew Simpson WWT Consulting & Catherine McIlwraith WWT

• Background to the project• Background to the project

• Lower (urban) catchment assessment

• Wetland options and project progress

• Upper (rural) catchment assessment

• Wetland options and project progress

East Kolkata Wetlands ParkOutline

• Partnership project

• Tewkesbury Nature Reserve Group, Environment Agency Natural EnglandEnvironment Agency, Natural England, Tewkesbury Borough Council, FWAG, WWT Consulting, Wildfowl & Wetlands Trust

• Funding from Environment Agency –Gloucestershire Green Urban Rivers Project

• Drivers• Drivers

• Water Framework Directive – waterbody of moderate ecological statusg

• Key aim

• Identify how wetlands across the landscape• Identify how wetlands across the landscape can be created or restored to:

• Improve the ecological status of the river and floodplain

• Improve surface water quality entering the river

• Reduce surface water flooding

• Maximise ecosystem service benefits

East Kolkata Wetlands ParkBackground

Undertake an options appraisal for restoration measures within the lower catchment thatmeasures within the lower catchment that would:

• Improve the `ecological status’ of the river• Improve the ecological status of the river (the watercourse, its floodplain and river corridor) through enhancements to water quality; physical form and function (geomorphology), biodiversity and habitats;

•• Identify and assess options for improved surface water management from surrounding residential areas; g

• Enhance the site as valuable public green space; andp

• Assess the potential to reduce damage/impact from flooding by improving g g y gthe distribution of water across the site and its boundaries.

East Kolkata Wetlands ParkSwilgate River Floodplain and River Restoration Study

East Kolkata Wetlands Park

East Kolkata Wetlands Park

East Kolkata Wetlands Park

East Kolkata Wetlands ParkConstraints

• Areas with land uses not compatible with wetland habitat creation such as the cricket clubhabitat creation such as the cricket club

• Current infrastructure such as roads, bridges, paths etc.

• Current ecological interest such as trees, hedgerows, ponds and wetland habitats

• Areas with existing bank protection such as walls etc.

East Kolkata Wetlands ParkConstraints to floodplain and river restoration

• Areas with unstable banks

• Areas which already have some flooding from the river• Areas which already have some flooding from the river

• Areas that hold surface water in topographic depressions

• A i ti l i l• Areas near existing ecological areas

• Areas where the channel is straightened, with steep sides and limited morphologyp gy

• Areas where drainage goes directly into the river without treatment or without slowing down the flow

• Areas where restoration could improve the amenity value of the site

East Kolkata Wetlands ParkOpportunities

East Kolkata Wetlands ParkRiver reaches

Restoration activity Features

Floodplain wetland habitat Ponds, scrapes, paleo channel features, swamp, pcreation

, p , p , p,reedbeds

Floodplain wetland for treatment SuDS and agricultural drainage wetlands toFloodplain wetland for treatment SuDS and agricultural drainage wetlands to provide water treatment and/or attenuation

Buffer strip creation and Reinstate riparian corridor, fencing, more targetedBuffer strip creation and re-vegetation

Reinstate riparian corridor, fencing, more targeted vegetation management

East Kolkata Wetlands ParkRestoration options – floodplain wetlands

East Kolkata Wetlands Park

East Kolkata Wetlands ParkOpportunities

Restoration activity Features

Bank reprofiling (major) Create wider more open channel, (requires 5-10m on either bank)

B k fili ( di ) M i l b h d iti lBank reprofiling (medium) Marginal benches, depositional zones, bank grading

Bank reprofiling (minor) Limited bank profiling to create moreBank reprofiling (minor) Limited bank profiling to create more variable marginal and bank profiles

Remeandering (passive) Allowing sinuous sections to develop andRemeandering (passive) Allowing sinuous sections to develop and meander without intervention

Remeandering (active) Developing the sinuosity of straightenedRemeandering (active) Developing the sinuosity of straightened reaches by repro-filing or collapsing banks into the wetted channel to initiate sinuosity

East Kolkata Wetlands ParkRestoration options – channel morphology

East Kolkata Wetlands Park

Restoration activity FeaturesSubstrate

l i h t/ h tTargeted sediment removal (degraded reaches),

l l i h t d b ld l treplenishment/enhancement gravel replenishment and boulder placement

Enhancement to variation in flow and depth

Creation of pool/riffle sequence, varied depth, flow deflectors etcand depth deflectors etc

Woody debris reintroduction Incorporate woody debris into the channel to increase the stability of the channel by absorbingincrease the stability of the channel by absorbing the energy of flood flows, reducing water velocity at low and moderate flows, and reducing erosion of the stream bank and stream bed at both localof the stream bank and stream bed at both local and regional scales

R d d i i All th f ti f h l b d i dRemove dredging regime Allow the formation of channel bars and varied marginal and in-channel vegetation

East Kolkata Wetlands ParkRestoration options – in-channel improvements

East Kolkata Wetlands Park

Restoration activity FeaturesRestoration activity FeaturesRiverine wetland creation (backwaters)

Online and offline backwaters within the bankfullwidth

Fish pass Structure to allow fish to pass weir barrier

East Kolkata Wetlands ParkRestoration options – online wetland creation

East Kolkata Wetlands Park

Section 1 Section 2, 3 & 4

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Floodplain wetland habitat creation

Bank reprofiling (major)

Riverine wetland creation (backwaters)

Remeandering (passive)

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Remeandering (passive)

Remeandering (active)

Buffer strip creation and re-vegetation

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Bank reprofiling (medium)

Floodplain wetland for treatment

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Substrate replenishment/enhancement

Enhancement to variation in flow and depth in flow and depthRemove dredging regime

Woody debris reintroduction

Bank reprofiling (minor)

10 10 5 3 4 5 1 12 8 5 10 1

East Kolkata Wetlands ParkRestoration options

Ecosystem Service Score (Biodiversity) Section 2, 3 & 4

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Floodplain wetland habitat creation 3 1 3 0 3 3 13 5

Bank reprofiling (major) 3 1 3 2 1 2 12 6 p g j

Riverine wetland creation (backwaters) 3 0 3 2 1 3 12 5

Remeandering (passive) 3 1 3 2 0 3 12 5

Remeandering (active) 3 1 3 2 0 3 12 5

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Buffer strip creation and re-vegetation 3 1 2 1 3 2 12 6

Bank reprofiling (medium) 3 0 3 2 1 2 11 5

Floodplain wetland for treatment 2 2 1 0 3 1 9 5

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Substrate replenishment/enhancement 3 0 3 3 0 0 9 3

Enhancement to variation in flow and dep 3 0 3 3 0 0 9 3

Remove dredging regime 3 0 3 1 1 0 8 4

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Woody debris reintroduction 1 1 3 1 0 1 7 5

Bank reprofiling (minor) 2 0 1 1 1 2 7 5

12 8 5 10 1

Restoration options – ecosystem service assessment

• Series of meetings held with:

• Local community

• Tewkesbury Borough Council

• Natural England

• Environment Agency

• FWAG

East Kolkata Wetlands ParkConsultation

• Improvement to public access

• Wetlands for surface water treatment

• Floodplain wetland restoration

• Channel modifications

East Kolkata Wetlands ParkNew vision for Priors Park

• Ecological surveys

• Hydrological surveys

• Soil surveys

• Topographical survey to ground-truth LiDARdata

• S i• Services survey

• Hydrological modelling

East Kolkata Wetlands ParkDetailed surveys

East Kolkata Wetlands ParkDetailed design of key features

Rural catchment assessment

• Assessment criteria:

1 Farms within ELS+ were given priority over ELS1. Farms within ELS+ were given priority over ELS.2. Priority was given to farms at a higher risk of surface and

fluvial flooding3. Farm land with an excess of a 2.3 0 slope was targeted over

flatter land. 4. Dairy farms were to be targeted over arable farms4. Dairy farms were to be targeted over arable farms

• High scoring farms were targeted as a priority for further i ti tiinvestigation.

• The catchment review identified a number of potentially suitable farms but all will require further investigation in the coming months to ascertain their suitability.

Targeted farmsg

Odessa Farm

Southend Farm

Odessa Farm

• 85 ha dairy holding ~120 cows• Manure and nutrient management is generally good but

li ht d ff i id tifi d b FWAG S th slight yard runoff issues were identified by FWAG South West site investigation

• Runoff from yard made worse by lack

f i of guttering on some buildings

Wetland treatment system designy g

• Overall system was sized to provide effective treatment and to store treatment and to store an extreme rain event

• Treatment stages are to include:

o Sediment pondo Sediment pondo Aeration cascadeo Wet swale

Di h t i ti o Discharge to existing ditch

• Construction to take place summer 2013

Ecosystem Services - Ramsary

S i K b fitService Key benefits

Provisioning services

• Potentially drinking water for livestock• Water for irrigated agricultureservices Water for irrigated agriculture

Regulating

• Storage and delivery of water as part of water supply systems for agriculture and industry

• Soil, sediment and nutrient retentionRegulating services • Water purification/waste treatment or dilution

• Support of predators of agricultural pests• Flood control, flood storage

Cultural services

• Nature observation and nature-based tourism• Spiritual inspiration• Importance for scientific reference and monitoring

Supporting i

• Supports a variety of all life forms including plants, animals and microorganisms, the genes they contain, and the ecosystems of which they form a partS li i d i i i f iservices • Storage, recycling, processing and acquisition of nutrients

• Carbon storage/sequestration• Support for pollinators

Project progressj p g

• Aimed to improve the ecological status of the Swilgate by taking a catchment approachg pp

• Identified where wetlands can be used to deliver catchment bj ti d id t i t iobjectives and provide extensive ecosystem services

• The project is still running and progressing wellThe project is still running and progressing well

• Construction of wetland features in both the urban and rural sections of the catchment is expected this year