responsive british hydrological society professional water ... · § district bisected by a water...

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www.scottwilson.comBHS – Water Cycle Strategies

British Hydrological Society

Water Cycle Strategies

WCS In Practice: Breckland Stage1 & Stage 2 WCS case Study

Carl Pelling

Principal Hydrology Consultant

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Presentation Format

§ What is a WCS - Key aims

§ Outline Methodology

§ Breckland WCS Case Study

§ Methodology

§ Key issues

§ Lessons Learned

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WCS – Scott Wilson Experience B o s t o n B C T h u r r o c k D C T h a m e s G a t e w a y–S o u t h E s s e xSCOPING

OUTLINE

DETAILED T e l f o r d &W r e k i nSITE SPECIFICM i l t o n K e y n e s G r e a t e rN o r w i c h D PB r e c k l a n d D CT h e t f o r dG r o w t h P tW e s t o n O t t m o o rG r e a t e r B e a u l i e u P a r k B o x t e d W o o dB a s s e t l a wB l a c k C o u n t r y W a v e n e y & G tY a r m o u t hN o r t h u m b e r l a n d C CG r e a t e rN o t t i n g h a m s h i r e

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WCS – Why?

Planning§ Ensures housing/employment growth targets are achievable

against water policy and legislation (WFD, PPS and RSS policy)

§ Provide (water) evidence base to LDF

§ Justification for promoting water policy (CS, DC & SPGs)

§ Input to infrastructure planning & costing DPDs

§ Minimise risk of stakeholder (EA, NE) objection to LDDs (water issues)

§ Water input to SA & HRA

Sustainability§ Minimise impact on water environment

§ Contribute to Sustainable Development

§ CC adaptation & mitigation

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WCS – Policy Drivers

§ RSS policy

§ PPS 1, 3, 12, 23 & 25

§ Water Framework Directive (RBMPs)

§ Future Water (government water strategy)

§ Draft Floods & Water Bill (Pitt Review)

§ Code for Sustainable Homes

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Breckland WCS - Stages

From Environment Agency WCS Guidance 2008

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Breckland WCS - Stages

§ Phase 1 Outline Study for Thetford NGP - March 2008

§ Phase 1 Outline Study for Breckland District – Oct 2008

§ Combined Phase 2 Detailed Study - ongoing

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Breckland WCS – Key Issues

§ Total growth approx 15,000 new homes

§ Large relative growth targets for small towns

§ District bisected by a water shed, growth towns located at headwaters of catchments

§ wastewater discharge issues - Small hydraulic and water capacity

§ Infrastructure capacity – close to BATNEEC, sewer flooding concerns

§ Water Resources Issues - Water dependent SACs & SSSI (Fens) linked to groundwater levels

§ Catchment Impacts – Downstream concerns, P loading (Wensum and Broads SAC and the Wash)

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Generic Outline Study Methodology

Data Collection and Review

Baseline assessment for preferred options

a) Environmentalb) Water services Infrastructure

Is capacity sufficient to accommodate all housing & Jobs?

YES NOOption DevelopmentOutline options development

Define Existing Capacity(environment & infrastructure)

Development option assessment – OUTLINE STUDY

Area Action PlansDETAILED STUDYFurther detailed assessmentsDetailed infrastructure optionsCost and phasing of optionsFunding optionsWater Efficiency PlanSite specific policy guidanceDeveloper Checklists

Surface water management

Ecological assessment

WFD & Climate change

Strategic water policy

Core Strategy & preferred options DPD

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Methodology Data Collection

Breckland District Council

§ Urban Capacity studies

§ Employment Studies

§ Preferred allocations

§ SFRA

Anglian Water Services

§ Wastewater & cleanwater networks

§ DG5 register data

§ Draft WRMPs

§ Abstraction licences

Environment Agency

§ GQA, CAMS, Consents

§ Draft RBMPs

Natural England

§ SAC, SPA, SSSI (hydrologically linked)

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Baseline - Environment

§ Flood Risk:§ Fluvial / tidal

§ Groundwater

§ Sewer flooding

§ Overland flow

§ = Flood Risk constraints

§ Water Resources:§ CAMS – available resources

§ WRMP – comparison of growth and WR options & S/D balance for WRZ

§ % utilisation of licences

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Baseline - Environment

§ Ecology:Habitats Regulations Ass – SAC, SPA,

RAMSAR

§ Screening (Outline) – hydrologically sensitive

§ Complete (Detailed) – hydrologically sensitive

Other Site screening – SSSI, LNR, RNR

§ Water Quality:WFD RBMP – draft status classifications

§ Failing Parameters

§ Proposed changes (POM)

§ At risk status

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5

5.5

6

6.5

7

7.5

8

8.5

9

9.5

10

160 165 170 175 180

chainage (m)

mA

OD

ground/bed level Qmed water levels

Infrastructure Capacity

§ Wastewater Treatment Capacity§ Volumetric headroom

§ Process capacity review

§ Receiving Watercourse Capacity§ Calculate likely wastewater generation

§ Water Quality & WFD – mass balance

§ Flood Risk – Mannings eqn

§ Sewer Network Capacity§ Network capacity calculations

§ Water Supply § Network capacity review

§ Pumping Stations

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Option Assessment

§ Water Resources§ Predict demand scenarios

§ Review demand management

§ Review WR options – outline costs

§ RoC – Sustainability reductions

§ Infrastructure

§ Wastewater treatment

§ Network – new or upgrades

§ Flood Risk

§ Strategic infrastructure

§ Strategic SuDS review

§ Link to SWMPs

Breckland Detailed WCS - Thetford Residential and Non-residential Demand Growth

- Scenario 1a & 1b

0.0

0.5

1.0

1.5

2.0

2.5

3.0

2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026

Years 2008 to 2026

Cu

mu

lati

ve

Gro

wth

in

De

ma

nd

(M

l/d

)

Max Non-Residential Land Area

Min Non-Residential Land Area

Thetford Residential Total

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Key Outline Study Output – Scenario Assessment

Wastewater

treatment

Wastewater

Network

Water

Resource

development

Water supply

network

Water

Environment

Flood Risk to

development

Flood Risk

Management

2008 - 2010 440 440 0 440

2010 - 2015 1763 1073 1130 2203

2015 - 2020 2400 1073 3530 4603

2021 - 2025 2500 1073 6030 7103

2025 - 2031 640 1073 6670 7743

Cumulative housing

total as infill

Housing

Numbers

in each

period

Years

Water cycle infrasructure constraints Water Environment constraints

Cumulative

housing total

Cumulative housing

total in new

development areas

Which Allocations & When?

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Outline Studies – key findings

§ 4 of the 5 WwTW would need upgrading before 2026;

§ Development in 4 of 5 towns would lead to failure of WFD standards;

§ 3 of the 5 towns require new strategic wastewater mains;

§ Flood risk is manageable at all sites (passes ST);

§ Strategic investment in water resources (& supply infrastructure) required to avoid impact on HD sites

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Phase 2 Detailed WCS

§ Commenced Summer 2009

§ Key issue to ensure solutions for wastewater discharge and WFD to support EiP;

§ Undertaken detailed RQP modelling to determine consents required to meet WFD;

§ Set up wastewater management group (AWS, EA and Breckland) to agree treatment options;

§ Attleborough = doubling of population, Amm-N and BOD at limits of BATNEEC

§ Immediate d/s P compliance not possible

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Phase 2 Detailed WCS

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Detailed WCS - Water Efficiency Plan

§ Water Use

§ Looking at different water use scenarios (CfSH)

§ May limit further volumetric upgrade requirements at WwTWs

§ Reduced reliance on new resources

§ Water Neutrality

§ Evidence base for water use policy

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Wastewater network options

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Detailed Strategy – Further Work

§ Costings & Phasing

§ Phasing

§ Funding Options

§ Consultation

§ Policy Guidance

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Developer Checklist

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WCS – Key Advantages

§ Water constraints can influence planning decisions

§ Reduce risk of EA objections to CS soundness

§ Evidence base for LDFs & RSS & SBPs

§ Dialogue: planners & infrastructure providers

§ Phasing

§ Funding – AMP process

§ Area specific water policy & evidence base

§ Early identification of Developer contributions/tarrifs

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Some challenges

§ Short timescales & LDF planning – decisions often already made on location and scale

§ Provision (timing and coverage) of data & Confidentiality

§ Water Company engagement

§ Inadequate Technical briefs – scope too wide

§ Level of assessment § low flow receiving capacity

§ Regional catchment issues

§ P – immediate d/s compliance

§ WFD and WRMP & Business Plan timings

§ Eco-towns

§ Site Specific WCS & EIA§ Still developing – no guidance

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Any Questions?

responsive british hydrological society professional water ... · § district bisected by a water...

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