JBA Consulting Report

Tandridge District Council Water Cycle Study – Phase 3 Detailed

December 2018

www.jbaconsulting.com

Tandridge District Council Council Offices Station Road East

Oxted Surrey RH8 0BT

Water Cycle Study (Stage 3) 2018 i

JBA Project Manager Alistair Clark 8a Castle Street Wallingford Oxfordshire OX10 8DL

Revision history Revision Ref/Date Amendments Issued to V1.0 05/11/2018 Draft Report Mark Bristow V2.0 10/12/2018 Final Report Mark Bristow V3.0 10/12/2018 Final Report with amendments Mark Bristow from the Environment Agency

Contract This report describes work commissioned by Tandridge District Council in February 2018. Tandridge District Council’s representative for the contract was Mark Bristow. Alistair Clark and Richard Pardoe of JBA Consulting carried out this work.

Prepared by ...... Richard Pardoe MSc MEng

Analyst

Reviewed by ...... Paul Eccleston BA CertWEM CEnv MCIWEM C.WEM

Technical Director Purpose This document has been prepared as a Final Report for Tandridge District Council. JBA Consulting accepts no responsibility or liability for any use that is made of this document other than by the Tandridge District Council for the purposes for which it was originally commissioned and prepared. JBA Consulting has no liability regarding the use of this report except to Tandridge District Council. Acknowledgements JBA Consulting would like to thank Mark Bristow of Tandridge District Council, Robert Kenway and Owen Davies from the Environment Agency, SES Water, Southern Water and Thames Water for their assistance in preparing this report. Copyright © Jeremy Benn Associates Limited 2018. Carbon footprint A printed copy of the main text in this document will result in a carbon footprint of 214g if 100% post-consumer recycled paper is used and 237g if primary-source paper is used. These figures assume the report is printed in black and white on A4 paper and in duplex. JBA is aiming to reduce its per capita carbon emissions.

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Executive summary In February 2018, JBA Consulting was commissioned by Tandridge Council to undertake a Water Cycle Study (WCS). This Phase 3 Detailed Study builds on the assessments completed in Phases 1 and 2 and provides evidence to support Tandridge’s Local Plan Process. This study assesses the potential issues relating to future development within Tandridge and the impacts on water supply, wastewater collection and waste water treatment. The Water Cycle Study is required to assess the constraints and requirements that will arise from potential growth on the water infrastructure. New homes require the provision of clean water, safe disposal of wastewater and protection from flooding. The allocation of large numbers of new homes in certain locations may result in the capacity of existing available infrastructure being exceeded, a situation that could potentially cause service failures to water and wastewater customers, adverse impacts to the environment, or high costs for the upgrade of water and wastewater assets being passed on to the bill payers. In addition to increased housing demand, future climate change presents further challenges to pressures on the existing water infrastructure network, including increased intensive rainfall events and a higher frequency of drought events. Sustainable planning for water must now take this into account. The water cycle can be seen in the figure below and shows how the natural and man-made processes and systems interact to collect, store or transport water in the environment. The Water Cycle

Source: Environment Agency – Water Cycle Study Guidance

This study will assist the council to select and develop sustainable development allocations where there is minimal impact on the environment, water quality, water resources, infrastructure, and flood risk. This has been achieved by identifying areas where there may be conflict between any proposed development, the requirements of the environment and by recommending potential solutions to these conflicts. The Water Cycle Study has been carried out in co-operation with the Environment Agency, SES Water, Southern Water and Thames Water, as well as the neighbouring Local Planning Authorities (LPAs).

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Potential development sites were provided by Tandridge District Council and wastewater treatment works (WwTW) likely to serve growth in the area were identified using the Environment Agency Consents database. Each development site was then allocated to a WwTW in order to understand the additional wastewater flow resulting from the planned growth. Infrastructure required to address issues identified in the Phase 2 Outline Study was assessed to answer the following questions:  What infrastructure is required  When is it needed?  Is the strategy sustainable?  How is it going to be funded and implemented? For the purposes of this study, development sites were grouped into wastewater catchment to allow assessments to be made at the site, catchment, and water resource zone scale. Indicative timescales for delivery of infrastructure required to serve growth in the district were presented and identified careful phasing of development sites may be required in order to ensure the right infrastructure is in place prior to sites being occupied, and to prevent deterioration in the water environment.

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Contents 1. Introduction ...... 8 1.1 Terms of Reference ...... 8 1.2 The Water Cycle ...... 8 1.3 Impacts of Development on the Water Cycle ...... 9 1.4 Objectives ...... 9 1.5 Study Area ...... 9 1.6 Record of Engagement...... 10 1.6.1 Introduction...... 10 1.6.2 Scoping Study Engagement ...... 10 2. Future Growth in Tandridge ...... 11 2.1 Study area ...... 11 2.2 Components of the growth forecast ...... 13 2.3 Changes to growth forecast used in Phase 2 ...... 13 3. Capacity for growth in Tandridge ...... 14 3.1 Introduction ...... 14 3.2 Beddington catchment ...... 15 3.3 Burstow catchment ...... 19 3.4 Felbridge catchment ...... 22 3.5 Godstone catchment ...... 25 3.6 Lingfield catchment ...... 28 3.7 Oxted catchment ...... 31 3.8 Reigate catchment ...... 34 4. Water Quality ...... 37 4.1 Groundwater Quality ...... 37 4.1.1 Groundwater Protection ...... 37 4.2 WINEP Schemes ...... 40 4.2.1 Introduction...... 40 4.2.2 Methodology ...... 42 4.2.3 Results ...... 43 4.2.4 Conclusion ...... 44 5. Sources of funding ...... 45 5.1 Water supply and wastewater infrastructure ...... 45 5.2 Developer Contributions and Utility Companies ...... 46 5.3 Water quality improvements...... 47 6. Summary and recommendations ...... 48 6.1 Summary of phase 3 detailed study ...... 48 A Site Tracker Spreadsheet ...... 49

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List of Figures Figure 1.1 The Water Cycle 9 Figure 2.1 Map of the water cycle study area 11 Figure 3.1 Wastewater catchments within Tandridge 14 Figure 3.2 Development sites within the Beddington catchment 15 Figure 3.3 Development identified in the Burstow wastewater catchment 19 Figure 3.4 Development sites within the Felbridge catchment 22 Figure 3.5 Development sites within the Godstone catchment 25 Figure 3.6 Development sites within the Lingfield catchment 28 Figure 3.7 Development sites in the Oxted catchment 31 Figure 3.8 Development sites in the Reigate catchment 34 Figure 4.1 Source Protection Zones in Tandridge 39 Figure 5.1 Typical water supply infrastructure connections and strategic assets. (Source: Southern Water) 45 Figure 5.2 Typical wastewater infrastructure connections and strategic assets (Source: Southern Water) 46

List of Tables Table 3.1 Summary of site assessments and growth in the Beddington catchment 16 Table 3.2 Summary of site assessments and growth in the Burstow catchment 20 Table 3.3 Summary of site assessments and growth in the Felbridge catchment 23 Table 3.4 Summary of site assessments and growth in the Godstone catchment 26 Table 3.5 Summary of site assessments and growth in the Lingfield catchment 29 Table 3.6 Summary of site assessments and growth in the Oxted catchment 32 Table 3.7 Summary of site assessments and growth in the Reigate catchment 35 Table 4.1 Development sites within Source Protection Zones 40 Table 4.2 WINEP Schemes in Tandridge 41 Table 4.3 WINEP PR19 baseline parameters 42 Table 4.4 Water quality modelling results and suggest permit level 43 Table 5.1 Links to water company infrastructure charges for 2018/2019 46

Abbreviations

ALS Abstraction Licensing Strategy AMP Asset Management Plan AMR Automatic Meter Reading AONB Area of Outstanding Natural Beauty AP Assessment Point ASNW Ancient Semi-Natural Woodland BIDS Business, Industrial, Distribution and Storage BOD Biochemical Oxygen Demand BREEAM Building Research Establishment Environmental Assessment Methodology CAMS Catchment Abstraction Management Strategies CAPEX Capital Expenditure CED Common End Date CFMP Catchment Flood Management Plan

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CfSH Code for Sustainable Homes CLP Comprehensive Local Plan CSO Combined Sewer Overflow DCLG Department of Communities and Local Government (Replaced by MHCLG) DWF Dry Weather Flow DWI Drinking Water Inspectorate DYAA Dry Year Annual Average DYCP Dry Year Critical Period EA Environment Agency EC European Community ECA European Communities Act EDNA Economic Development Needs Assessment EFI Ecological Flow Indicator EP Environmental Permit EU European Union FEH Flood Estimation Handbook FFT Flow to Full Treatment FWMA Flood and Water Management Act FZ Flood Zone GES Good Ecological Status GIS Geographic Information Systems HOF Hands-Off Flow HOL Hands-off Level IDB Internal Drainage Board IDP Infrastructure Delivery Plan JBA Jeremy Benn Associates LLFA Lead Local Flood Authority LPA Local Planning Authority l/p/d Litres per person per day Ml/d Mega (Million) litres per day MHCLG Ministry of Housing Communities and Local Government NE Natural England

NH4 Ammonia NPPF National Planning Policy Framework NYAA Normal Year Average Annual OAN Objectively Assessed Need OfWAT Water Service Regulation Authority ONS Office of National Statistics OPEX Operational Expenditure OS Ordnance Survey P Phosphorous PDL Previously Developed Land

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PE Population Equivalent p/h Person per house PPS Planning Policy Statement RAG Red / Amber / Green assessment RBD River Basin District RBMP River Basin Management Plan ReFH Revitalised Flood Hydrograph RNAG Reason for Not Achieving Good (Status) RoFSW Risk of Flooding from Surface Water (replaced uFMfSW) RQP River Quality Planning tool RZ Resource Zone SA Sustainability Appraisals SAC Special Area of Conservation SBP Strategic Business Plan SEA Strategic Environmental Assessment SFRA Strategic Flood Risk Assessment SHELAA Strategic Housing and Economic Land Availability Assessment SHMA Strategic Housing Market Assessment SPA Special Protection Area SPD Supplementary Planning Document SPZ Source Protection Zone SS Suspended Solids SSSI Site of Special Scientific Interest SU Sewerage Undertaker SW Southern Water SuDS Sustainable Drainage Systems SWMP Surface Water Management Plan TCAMS Thames Catchment Abstraction Management Strategy TDC Tandridge District Council TW Thames Water uFMfSW Updated Flood Map for Surface Water UWWTD Urban Waste Water Treatment Directive WaSC Water and Sewerage Company WCS Water Cycle Study WFD Water Framework Directive WINEP Water Industry Environment Programme WRMP Water Resource Management Plan WRZ Water Resource Zone WQA Water Quality Assessment WSZ Water Supply Zone WTW Water Treatment Works WwTW Wastewater Treatment Works

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1. Introduction

1.1 Terms of Reference JBA Consulting was commissioned by Tandridge District Council to undertake a Water Cycle Study (WCS) for Tandridge to inform the Local Plan. The purpose of the WCS is to form part of a comprehensive and robust evidence base for the Local Plan which will set out a vision and framework for development in the area up to 2033 and will be used to inform decisions on the location of future development. Unmitigated future development and climate change can adversely affect the environment and water infrastructure capability. A WCS will provide the required evidence, together with an agreed strategy to ensure that planned growth occurs within environmental constraints, with the appropriate infrastructure in place in a timely manner so that planned allocations are deliverable.

1.2 The Water Cycle National Planning Policy Framework Practice Guidance on Water Supply, Wastewater and Water Quality1 describes a water cycle study as: "a voluntary study that helps organisations work together to plan for sustainable growth. It uses water and planning evidence and the expertise of partners to understand environmental and infrastructure capacity. It can identify joined up and cost-effective solutions, that are resilient to climate change for the lifetime of the development. The study provides evidence for Local Plans and sustainability appraisals and is ideally done at an early stage of plan-making. Local authorities (or groups of local authorities) usually lead water cycle studies, as a chief aim is to provide evidence for sound Local Plans, but other partners often include the Environment Agency and water companies." The Environment Agency's guidance on WCS2 recommends a phased approach:  Phase 1: Scoping study, focussing on formation of a steering group, identifying issues for consideration and the need for an outline study.  Phase 2: Outline study, to identify environmental constraints, infrastructure constraints, a sustainability assessment and consideration of whether a detailed study is required.  Phase 3: Detailed study, to identify infrastructure requirements, when they are required, how they will be funded and implemented and an overall assessment of the sustainability of proposed infrastructure. Figure 1.1 below shows the main elements that compromise the Water Cycle and shows how the natural and man-made processes and systems interact to collect, store or transport water in the environment.

————————————————————————————————————————————— 1 Planning Practice Guidance: Water supply, wastewater and water quality, Department for Communities and Local Government (2014). Accessed online at: http://planningguidance.planningportal.gov.uk/blog/guidance/ on: 09/03/2018 2 Water Cycle Study Guidance, Environment Agency (2009). Accessed online at: http://webarchive.nationalarchives.gov.uk/20140328084622/http://cdn.environment-agency.gov.uk/geho0109bpff- e-e.pdf on: 09/03/2018

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Figure 1.1 The Water Cycle

1.3 Impacts of Development on the Water Cycle New homes require the provision of clean water, safe disposal of wastewater and protection from flooding. It is possible that allocating large numbers of new homes at some locations may result in the capacity of the existing available infrastructure being exceeded. This situation could potentially lead to service failures to water and wastewater customers, have adverse impacts on the environment or cause the high cost of upgrading water and wastewater assets being passed on to bill payers. Climate change presents further challenges such as increased intensity and frequency of rainfall and a higher frequency of drought events that can be expected to put greater pressure on the existing infrastructure.

1.4 Objectives As a WCS is not a statutory instrument, Local Planning Authorities are advised to prioritise the different stages of the WCS to integrate with their Local Plan programme. This detailed report is written to support the development of the Local Plan (LP) building on the assessment made in the Phase 2 Outline study. Specific requirements, specified by the project brief, were to identify:  infrastructure requirements to support the proposed growth  when they are required;  and how they might be funded The Environment Agency also requested that the water quality modelling completed in phase two be updated to include the latest Water Industry Environment Programme (WINEP) targets. This report therefore presents an assessment of the effect of proposed growth of the proposed PR19 WINEP planning. The impact of development on groundwater quality is also considered.

1.5 Study Area This WCS outline report has been prepared for Tandridge District Council. This Local Authority area covers 248km2, includes the towns of Caterham, Godstone, Lingfield, and Oxted and has a population of approximately 87,000.

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The area is located within the River Mole, and River Medway catchments to the west and east respectively. The area north of the North Downs is in the catchment of the Caterham Bourne. Water supply services for Tandridge are provided by SES Water, and wastewater serves are split between Thames Water (TW) and Southern Water (SW).

1.6 Record of Engagement

1.6.1 Introduction Preparation of a WCS requires significant engagement with stakeholders, within the Local Planning Authority area, with water and wastewater utilities, with the environment agency, and where there may be cross-boundary issues, with neighbouring local authorities. This section forms a record of engagement for the WCS.

1.6.2 Scoping Study Engagement The preparation of the Detailed study was supported by the following engagement: Stakeholder Workshop Engaged Parties TDC Environment Agency SES Water Southern Water Thames Water (Reigate and Banstead Borough Council were invited to the meeting but could not attend). Details Outcomes of Phase 2 Outline Study Methodology for Phase 3 Data collection requirements

Further Engagement Engaged Parties TDC Environment Agency SES Water Southern Water Thames Water Details Discussion of aspects of infrastructure provision and the outcomes of the Phase 3 study were discussed with the water companies and the EA.

Engaged Parties TDC Environment Agency Details Discussion of water quality methodology and implications for WINEP/PR19 targets.

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2. Future Growth in Tandridge

2.1 Study area Figure 2.1 shows the location of development sites under consideration within the Tandridge District Council boundary. Figure 2.1 Map of the water cycle study area

Note: This map includes the Garden Community sites at Redhill Aerodrome and Blindley Heath which are no longer being taken forward in the planning process.

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2.2 Components of the growth forecast In Phases 1 and 2, a forecast for growth during the Local Plan period was defined. This consisted of the following components:  Housing and Economic Land Availability Assessment (HELAA)  Garden community sites  Commitments (development sites already in the planning system, but not yet built)  Windfall  Development from outside the Tandridge boundary but served by infrastructure within or shared with Tandridge. A full description of this growth forecast can be found in the Phase 2 report.

2.3 Changes to growth forecast used in Phase 2 Since publication of the Phase 2 study, the development sites have been further refined and each has been given a Local Plan reference number. For consistency the original site references used in Phase 2 have been included alongside the new references. The Council have also provided an updated trajectory which has been used to modify the Phase 2 growth forecast. The publication of the revised National Planning Policy Framework (2018) confirmed the Government’s commitment to using a standardised methodology to calculate housing need from each authority. The Ministry for Housing, Communities and Local Government released a technical consultation in October 2018 proposing that 2014 based data should be used instead of the later 2016 based dataset to provide the demographic baseline for assessment of local housing need. These changes are subject to further announcements in 2019, and so it has been decided to continue to use the Objectively Assessment Need (OAN) presented in Phases 1 and 2.

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3. Capacity for growth in Tandridge

3.1 Introduction For the purpose of the Phase 3 study, Tandridge has been divided into wastewater catchments shown in Figure 3.1 below, which cover all of the development sites identified.

Figure 3.1 Wastewater catchments within Tandridge Summary assessments for each site are presented alongside catchment level summaries of infrastructure requirements for each wastewater catchment.

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3.2 Beddington catchment All of the identified development sites north of the M25 lie within the Beddington WwTW catchment which covers the settlements of Caterham, Caterham on the Hill, Warlingham, Woldingham and Whyteleafe. Thames Water’s Beddington WwTW serves a large area of south London, and the area served within Tandridge represents a small proportion of this. For this reason, catchment level assessments of infrastructure were not performed.

Figure 3.2 Development sites within the Beddington catchment

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Table 3.1 Summary of site assessments and growth in the Beddington catchment Local Phase 2 Housing Indicative Water Wastewater Odour Plan Site ref. units no. supply network Site ref. employees HSG05 UCS 02 29 0 Green Green Green HSG06 CAT 040 75 0 Amber Green Green HSG07 CAT 081 15 0 Green Green Green HSG08 CAT 007 59 0 Amber Green Green HSG09 CAT 044 6 0 Green Green Green WAR 005 90 0 Amber Amber Green HSG15 WAR 036 100 0 Amber Green Green WAR 011 25 0 Green Green Green HSG16 WAR 023 25 0 Green Green Green HSG17 WAR 012 50 0 Amber Green Green HSG18 WAR 019 110 0 Amber Green Green HSG19 WAR 016 6 0 Green Green Green HSG20 CMP1 82 0 Amber Green Green CAT 079 6 0 Green Green Green CMP2 194 224 Green Amber Green TLP28 CMP4 20 32 Green Green Green CMP6 15 19 Amber Green Green Allocation Total 848 275 Windfall 306 N/A Commitments 711 49

Neighbouring Not assessed authority growth Total 1,865 324

Growth within this catchment is predominantly in existing built up areas. Network reinforcement may be required for most of the development sites to avoid a detrimental impact on existing customers. TLP28 consists of four sites, some of which require reinforcement to the wastewater network. This will need to be carefully phased to ensure this work is completed prior to developments being occupied. A typical lead time of 2-3 years has been advised by Thames Water from confirmation of development through to completion.

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures technologies WwTW Flow Capacity Assessment available exceeded identified Water Company Growth in Tandridge represents an insignificant level of growth in this WwTW Beddington Catchment Capacity (based on existing assets) LPA A flow capacity assessment would require analysis of growth across a large Developer proportion of south London. For this reason a flow capacity assessment was not performed

2000 Additional homes (cumulative) Indicative employment (cum) 400

1000

200 Homes

0 0 Additional homes 180 274 324 127 17 183 307 202 17 17 49 67 17 17 17 17 17 17 0 0 Additional homes (cumulative) 180 454 778 905 922 1105 1412 1613 1630 1647 1696 1763 1780 1797 1814 1831 1848 1865 1865 1865 Indicative employment (no. emp.) 0 27 54 0 0 95 74 74 0 0 0 0 0 0 0 0 0 0 0 0

Indicative employment (cum) 0 27 81 81 81 176 250 324 324 324 324 324 324 324 324 324 324 324 324 324

2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 Year 2017 Water Company AMP 6 7 8 9 10 Funding Source Comments Sufficient water resource to serve Water resources N/A development in this catchment HSG05 HSG06 Network Reinforcement Network reinforcement for these Network reinforcement is required on HSG07 sites would be paid for through the certain sites in order to avoid HSG08 Network Reinforcement HSG09 infrastructure charge by developers. detriment to exisitng customers. HSG15 Network Reinforcement Phasing of TLP28 should be carefully Water supply HSG16 HSG17 Network Reinforcement managed with SES Water. HSG18 Network Reinforcement HSG19 HSG20 Network Reinforcement TLP28 Network Reinforcement HSG05 HSG06 Network reinforcement for these Network reinforcement is required on HSG07 sites would be paid for through the HSG15 and TLP28 sites. HSG08 HSG09 infrastructure charge by developers. Phasing of TLP28 should be carefully HSG15 Network Reinforcement managed with Thames Water as they Wastewater collection HSG16 HSG17 have advised a 2-3-year lead time for HSG18 HSG19 a programme of network works. HSG20 TLP28 Network Reinforcement

Not assessed See volumetric assessment Wastewater treatment comments above.

Water quality Not assessed

Flood risk from additional Not assessed wastewater discharge

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3.3 Burstow catchment The south west of Tandridge is served by Thames Water’s Burstow WwTW, which covers the settlements of Burstow, Smallfield and Outwood, with most of the development clustered around Smallfield.

Figure 3.3 Development identified in the Burstow wastewater catchment

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Table 3.2 Summary of site assessments and growth in the Burstow catchment Local Phase 2 Housing Indicative Water Wastewater Odour Plan site ref. units no. supply network Site ref. employees SMA 004 108 0 Amber Green Green HSG01 SMA 008 40 0 Green Green Green SMA 040 10 0 Amber Green Green HSG02 SMA 015 15 0 Amber Green Green HSG03 SMA 030 120 0 Green Amber Green HSG04 SMA 039 10 0 Amber Green Green SES02 ENA16 0 8 Green Green Green Allocation total 303 8

Windfall 54 0 Commitments 26 6 Neighbouring 0 0 authority growth Total Growth 383 14 Note: Part of SES02 (ENA22) is in the Felbridge catchment. As ENA22 is far larger than ENA16, the assessment for SES02 is contained within the Felbridge assessments. Burstow WwTW is currently close to its flow consent and is likely to exceed this between 2020 and 2025. No upgrades at Burstow are currently planned, however Thames Water confirmed that “we will deliver a scheme to meet the environmental driver once it is finally agreed”. The village of Smallfield has a history of flooding, which could be exacerbated if surface water is not managed appropriately from these new developments. The Level 2 SFRA recommends the use of SuDS on these sites. Recommendation: Tandridge District Council should discuss the phasing of developments within this catchment with Thames Water to ensure that capacity is available at Burstow WwTW to serve this growth, as no upgrade scheme is currently defined.

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures technologies WwTW Flow Capacity Assessment available exceeded identified Water Company Burstow catchment Capacity (based on existing assets) LPA Developer

600 Additional homes (cumulative) 20 Indicative employment (cum) 400 10

Homes 200

0 0 Additional homes 7 9 21 4 23 18 103 120 60 3 3 3 3 3 3 3 3 3 0 0 Additional homes (cumulative) 7 16 37 41 64 82 185 305 365 368 371 374 377 380 383 386 389 392 392 392 Indicative employment (no. emp.) 0 1 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Indicative employment (cum) 0 1 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 Year 2017 Water Company AMP 6 7 8 9 10 Funding Source Comments Sufficient water resource to serve Water resources N/A development in this catchment HSG01 Network Reinforcement Network reinforcement for these Network reinforcement is required on Water supply HSG02 Network Reinforcement HGS03 sites would be paid for through the certain sites in order to avoid HSG04 Network Reinforcement infrastructure charge by developers. detriment to exisitng customers. HSG01 Network reinforcement for these Network reinforcement is required on Wastewater collection HSG02 Network Reinforcement sites would be paid for through the certain sites. HGS03 HSG04 Network Reinforcement infrastructure charge by developers. Upgrades to Burstow WwTW would Thames Water confirmed "will No scheme yet defined be funded through Thames Water's deliver a scheme to meet the Wastewater treatment business plan. environmental driver once it is finaly agreed". The Ph2 study showed that growth WINEP PR19 Phosphurus Improvement Scheme / Urban wastewater could be accommodated with less improvement scheme Water quality than a 10% deterioration and no deterioration in class in any of the three sanitary determinands.

Flood risk from additional N/A Insignificant risk of flooding from wastewater discharge additional wastewater discharges.

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3.4 Felbridge catchment Southern Water’s Felbridge WwTW serves an area in the south of Tandridge including Felbridge, and the north west of East Grinstead in the Mid Sussex area. Three employment sites are planned within this catchment.

Figure 3.4 Development sites within the Felbridge catchment

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Table 3.3 Summary of site assessments and growth in the Felbridge catchment Local Phase 2 Housing Indicative Water Wastewater Odour Plan Site ref. units no. supply network Site ref. employees IES01 ENA 27 0 38 Green Green Green SES02 ENA 22 1 769 Amber Green Amber Allocation total 1 815

Windfall 0 0 Commitments 28 81 Neighbouring 63 0 authority growth Total Growth 92 896 Note: Part of SES02 (ENA16) is in the Burstow catchment. Felbridge WwTW is currently close to its flow consent, and a small exceedance is possible from 2025. Demand management, for example water efficiency measures in the new developments and with existing customers, could potentially be used to managed wastewater flows in this catchment in order to avoid the need for an upgrade of the flow consent.

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures technologies WwTW Flow Capacity Assessment available exceeded identified Water Company Felbridge catchment Capacity (based on existing assets) LPA Felbridge WwTW Developer 2.000 1.800 150 Additional homes (cumulative) 2000 1.600 Indicative employment (cum) 1.400 100 1.200 1000 1.000 Homes 50

0.800 Flow (Ml/d) 0 0 0.600 Additional homes 30 37 24 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.400 Future flow 0.200 Additional homes (cumulative) 30 67 91 91 92 92 92 92 92 92 92 92 92 92 92 92 92 92 92 92 Permit 0.000 Indicative employment (no. emp.) 0 21 0 60 815 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2015 2020 2025 2030 2035 Indicative employment (cum) 0 21 21 81 896 896 896 896 896 896 896 896 896 896 896 896 896 896 896 896

Year

IES01 Network reinforcement for these Network reinforcement is required on Water supply sites would be paid for through the SES02 in order to avoid detriment to SES02 Network Reinforcement infrastructure charge by developers. exisitng customers.

IES01 Network reinforcement for these Network reinforcement is required on Wastewater collection sites would be paid for through the SES02. SES02 Network Reinforcement infrastructure charge by developers. Upgrades to Felbridge WwTW would Water efficiency measures could Wastewater treatment be funded through Southern Water's reduce pressure on this WwTW business plan. The Ph2 study showed that growth WINEP PR19 Phosphorus improvement scheme could be accommodated with less Water quality than a 10% deterioration and no deterioration in class in any of the three sanitary determinands.

Flood risk from additional N/A Insignificant risk of flooding from wastewater discharge additional wastewater discharges.

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3.5 Godstone catchment Thames Water’s Godstone WwTW serves an area in the centre of Tandridge District south of the M25 that includes the settlements of Bletchingley, Godstone, and Tandridge.

Figure 3.5 Development sites within the Godstone catchment

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Table 3.4 Summary of site assessments and growth in the Godstone catchment Local Phase 2 Housing Indicative Water Wastewater Odour Plan Site ref. units no. supply network Site ref. employees HSG10 GOD 021 18 0 Amber Green Green HSG11 GOD 010 150 0 Amber Amber Green IES02 ENA 30 0 714 Amber Amber Green Allocation total 168 714 Windfall 36 0 Commitments 52 0

Neighbouring 0 0 authority growth Total Growth 256 714

Reinforcement of the water supply network is required at all three sites, and reinforcement is required to the wastewater network at two of the sites. Due to the longer lead time to provide wastewater infrastructure advised by Thames Water, a decision may need to be made on HSG11 and IES02 very soon in order to allow the infrastructure to be provided for these sites to meet the planned trajectory.

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures WwTW Flow Capacity Assessment technologies available exceeded identified Water Company Godstone catchment Capacity (based on existing assets) LPA Developer

300 Additional homes (cumulative) 1000 Indicative employment (cum) 200 500

Homes 100

0 0 Additional homes 11 14 48 5 2 2 2 2 2 2 2 52 52 52 2 2 2 2 0 0 Additional homes (cumulative) 11 25 73 78 80 82 84 86 88 90 92 144 196 248 250 252 254 256 256 256 Indicative employment (no. emp.) 0 0 0 0 250 250 214 0 0 0 0 0 0 0 0 0 0 0 0 0

Indicative employment (cum) 0 0 0 0 250 500 714 714 714 714 714 714 714 714 714 714 714 714 714 714

HSG10 Network Reinforcement Network reinforcement for these Network reinforcement is required on sites would be paid for through the all three site in order to avoid Water supply HSG11 Network Reinforcement infrastructure charge by developers. detriment to exisitng customers. IES02 Network Reinforcement

HSG10 Network reinforcement for these Network reinforcement is required sites would be paid for through the for HSG11 and IES02. Wastewater collection HSG11 Network Reinforcement infrastructure charge by developers. IES02 Network Reinforcement

N/A Capacity is available at Godstone Wastewater treatment WwTW for the local plan period.

Upgrades at this WwTW would be Ammonia is predicted to deteriorate WINEP PR19 Phosphorus improvement scheme funded through Southern Water's by 10% or more and Phosphate, business plan already classed as Bad, deteriorating Tightening of permit and associated treatment Water quality by more than 3%. In both cases, improvements deterioration can be limited through infrastructure improvements and tighter permit limits

Flood risk from additional N/A Insignificant risk of flooding from wastewater discharge additional wastewater discharges.

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3.6 Lingfield catchment Southern Water’s Lingfield WwTW serves an area in the east of Tandridge including the settlements of South Godstone, Crowhurst, Blindley Heath, Lingfield, Dormansland and Dormans Park. The most significant growth in this catchment is the Garden Community site (GV3) at South Godstone.

Figure 3.6 Development sites within the Lingfield catchment

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Table 3.5 Summary of site assessments and growth in the Lingfield catchment Local Indicative Phase 2 Housing Water Wastewater Plan Site no. Odour Site ref. units supply network ref. employees SGC01 GV3 4,000 2,619 Amber Amber Green LIN 030 50 0 Green Green Green HSG12 UCS11 11 0 Green Green Green IES06 ENA 23 0 149 Green Green Green SES03 ENA 12 0 204 Amber Green Green Allocation total 4,061 2,972 Windfall 18 0 Commitments 57 26

Neighbouring 0 0 authority growth Total Growth 4,136 2,998 Note: this includes growth beyond the Local Plan period at the Garden Community site

The Garden Community site will require the most extensive infrastructure and SES Water and Southern Water should be involved early in the project to ensure that the site is planned with this in mind. SES Water have advised that a new connection to the Blindley Heath trunk main is likely to be required which may be up to 5km long. With such a large site, the geography of site phasing could be very significant to the scale and phasing of water and wastewater network infrastructure. Lingfield WwTW has the capacity to serve development for the Local Plan period, but the level of growth at the Garden Community site is likely cause the flow consent to be exceeded between 2035 and 2040, and the total future demand from this site should be considered by Southern Water in their planning. A future upgrade at this WwTW may require an extension the existing site, and a policy may need to be contained in the Local Plan to ensure land is safeguarded for this purpose. Recommendation: A policy should be included in the Local Plan safeguarding land around Lingfield WwTW for upgrades at this WwTW to allow capacity beyond the Local Plan period as the South Godstone Garden Community Site expands.

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures technologies WwTW Flow Capacity Assessment available exceeded identified Water Company Lingfield Catchment Capacity (based on existing assets) LPA Developer

3000 Additional homes (cumulative) 2000 Indicative employment (cum) 2000 1000

Homes 1000

0 0 Additional homes 13 15 29 4 1 62 1 1 81 201 201 201 201 201 201 201 201 201 240 240 Additional homes (cumulative) 13 28 57 61 62 124 125 126 207 408 609 810 1011 1212 1413 1614 1815 2016 2256 2496 Indicative employment (no. emp.) 0 0 0 0 250 250 214 0 0 0 0 0 0 0 0 0 0 0 0 0

Indicative employment (cum) 0 0 0 0 250 500 714 714 714 714 714 714 714 714 714 714 714 714 714 714

SGC01 New connection to Blindley Heath trunk main Network reinforcement for these Network reinforcement is required to sites would be paid for through the accommodate SES03 and the Garden HSG12 Water supply infrastructure charge by developers. Community site in order to avoid IES06 detriment to exisitng customers.

SES03 Network Reinforcement

SGC01 Network Reinforcement Network reinforcement for these Network reinforcement would be HSG12 sites would be paid for through the required in order to accommodate Wastewater collection IES06 infrastructure charge by developers. the Garden Community site. SES03

Safeguard land for extension of WwTW beyond 2035 N/A Capacity is available at Lingfield WwTW for the local plan period, but Wastewater treatment the permit could be exceeded after 2035. Upgrades at this WwTW would be Increased effluent discharges are WINEP PR19 Phosphorus improvement scheme funded through Southern Water's predicted to lead to a deterioration business plan of 10% or more, and/or of class. In all cases, deterioration could be Water quality Tightening of permit and associated treatment improvements prevented by a tightening of permits and possible infrastructure improvements for effluent to be treated at TAL.

Flood risk from additional N/A Insignificant risk of flooding from wastewater discharge additional wastewater discharges. Water Cycle Study (Stage 3) 2018 30

3.7 Oxted catchment Southern Water’s Oxted WwTW is situated in the east of the study area and serves growth south of the M25 including the settlements of Limpsfield, Oxted, Hurst Green, and Holland. Growth in this catchment is mostly within Oxted, with some development sites identified in Hurst Green.

Figure 3.7 Development sites in the Oxted catchment

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Table 3.6 Summary of site assessments and growth in the Oxted catchment Local Phase 2 Housing Indicative Water Wastewater Odour Plan Site ref. units no. supply network Site ref. employees SES03 ENA 8 0 548 Amber Green Green HSG13 OXT 021 62 0 Green Green Green HSG14 OXT 067 50 0 Amber Amber Amber OXTC1 10 46 Green Green Green TLP29 UCS 09 50 0 Green Green Green Allocation total 172 594 Windfall 72 0 Commitments 176 125

Neighbouring 0 0 authority growth Total Growth 420 719

Oxted WwTW is currently exceeding its flow permit due to infiltration. Southern Water have an infiltration reduction scheme in their draft PR19 plan which should enable Southern Water to meet the forecasted growth in Oxted catchment in 2020-2025. Recommendation: Tandridge District Council should liaise with Southern Water to ensure the phasing of development within the Oxted catchment is line with capacity at Oxted WwTW. Southern Water should also discuss the impact of the infiltration reduction scheme in this catchment with the Environment Agency to understand the requirement for a tighter Phosophorus permit.

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures technologies WwTW Flow Capacity Assessment available exceeded identified Water Company Oxford Catchment Capacity (based on existing assets) LPA Developer

Additional homes (cumulative) 1500 Indicative employment (cum) 500 1000

Homes 500

0 0 Additional homes 20 55 105 67 56 34 66 4 4 4 4 4 4 54 4 4 4 4 0 0 Additional homes (cumulative) 20 75 180 247 303 337 403 407 411 415 419 423 427 481 485 489 493 497 497 497 Indicative employment (no. emp.) 2 55 67 0 346 200 48 0 0 0 0 0 0 0 0 0 0 0 0 0

Indicative employment (cum) 2 57 124 124 470 670 718 718 718 718 718 718 718 718 718 718 718 718 718 718

SES03 Network Reinforcement Network reinforcement for these Network reinforcement is required on HSG13 sites would be paid for through the all SES03 and HSG14 in order to avoid Water supply HSG14 Network Reinforcement infrastructure charge by developers. detriment to exisitng customers. TLP29

SES03 Network reinforcement for these Network reinforcement is required HSG13 sites would be paid for through the for HSG14. Wastewater collection HSG14 Network Reinforcement infrastructure charge by developers. TLP29

Infiltration works are planned during AMP7 that are designed to address the permit exceedence Infiltration reduction works are being Wastewater treatment paid for through Southern Water's business plan.

WINEP PR19 Phosphorus improvement scheme The Ph2 study showed that growth could be accommodated with less Water quality than a 10% deterioration and no deterioration in class in any of the three sanitary determinands.

Flood risk from additional N/A Insignificant risk of flooding from wastewater discharge additional wastewater discharges. Water Cycle Study (Stage 3) 2018 33

3.8 Reigate catchment Thames Water’s Reigate WwTW serves an area in the west of Tandridge including the settlements of Nutfield, South Nutfield, and Redhill Aerodrome. Within neighbouring Reigate and Banstead, this catchment also serves Reigate and Redhill.

Figure 3.8 Development sites in the Reigate catchment

There are no sites currently identified in the Local Plan within this catchment, although there are some committed sites.

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Table 3.7 Summary of site assessments and growth in the Reigate catchment Site ref. Housing Indicative no. Water Wastewater Odour units employees supply network Allocation 0 0 total Windfall 18 0 Commitments 49 47 Neighbouring authority 1,396 0 growth Total Growth 8,463 2,869

Reigate WwTW is currently close to its flow consent, and an upgrade scheme is currently going ahead which will accommodate growth up to 2033. Additional development in this catchment would require a step change in treatment technology which is not included in the current plan. Thames Water provided additional comment about this WwTW: “Earlswood (Reigate) STW is currently close to its permit and a planned upgrade is to be delivered by March 2021. Much of the growth in this catchment is from outside Tandridge and is likely to be accommodated through the planned capacity upgrade. Thames Water have concerns should Redhill Aerodrome garden community site be adopted as additional upgrades will be required, would be likely to cost tens of millions of pounds and take 3 to 5 five years to plan and deliver. Phasing of future enhancements to our works will be planned in consultation with all key stakeholders to ensure capacity is delivered in a timely manner beyond the design horizon of our current upgrades.”

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Conventional Water Cycle Timeline Capacity Capacity Major contraints Measures technologies WwTW Flow Capacity Assessment available exceeded identified Water Company Reigate Catchment Capacity (based on existing assets) LPA Developer

2000 Additional homes (cumulative) 200 Indicative employment (cum)

1000 100 Homes

0 0 Additional homes 14 46 87 96 196 195 131 131 131 131 131 131 38 1 1 1 1 1 0 0 Additional homes (cumulative) 14 60 147 243 439 634 765 896 1027 1158 1289 1420 1458 1459 1460 1461 1462 1463 1463 1463 Indicative employment (no. emp.) 0 20 16 11 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Indicative employment (cum) 0 20 36 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47

Water supply No development sites for assessment

Wastewater collection No development sites for assessment

Additional capacity at Reigate WwTW is close to capacity. Wastewater treatment WwTW is part of Thames Water's current business plan.. An assessment in Ph2 using SIMCAT WINEP PR19 Phosphorus improvement scheme showed a less than 3% deterioration Water quality in any determinand.

Flood risk from additional N/A Insignificant risk of flooding from wastewater discharge additional wastewater discharges.

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4. Water Quality

4.1 Groundwater Quality

4.1.1 Groundwater Protection Groundwater is an important source of water in England and Wales, and much of Tandridge district’s water supply is derived from groundwater sources. The Environment Agency is responsible for the protection of “controlled waters” from pollution under the Water Resources Act 1991. These controlled waters include all watercourses and groundwater contained in underground strata. The source protection zones are based on an estimate of the time it would take for a pollutant which enters the saturated zone of an aquifer to reach the source of abstraction or discharge point (Zone 1 = 50 days, Zone 2 = 400 days, Zone 3 is the total catchment area). The Environment Agency use SPZs (alongside other datasets such as the Drinking Water Protected Areas (DrWPAs) and aquifer designations as a screening tool to show:  areas where it would object in principle to certain potentially polluting activities, or other activities that could damage groundwater,  areas where additional controls or restrictions on activities may be needed to protect water intended for human consumption  how it prioritises responses to incidents. The EA have published a position paper3 outlining its approach to groundwater protection which includes direct discharges to groundwater, discharges of effluents to ground and surface water runoff. This is of relevance to this water cycle study where a development may manage surface water through SuDS. Sewage and trade effluent Discharge of treated sewage of 2m3 per day or less to ground are called small sewage discharges (SSDs). The majority of SSDs do not require an environmental permit if they comply with certain qualifying conditions. A permit will be required for all SSDs in source protection zone 1 (SPZ1). For treated sewage effluent discharges, the EA encourages the use of shallow infiltration systems, which maximise the attenuation within the drainage blanket and the underlying unsaturated zone. Whilst some sewage effluent discharges may not pose a risk to groundwater quality individually, the cumulative risk of pollution from aggregations of discharges can be significant. Improvement or pre-operational conditions may be imposed before granting an environmental permit. The EA will only agree to developments where the addition of new sewage effluent discharges to ground in an area of existing discharges is unlikely to lead to an unacceptable cumulative impact. Generally, the Environment Agency will only agree to developments involving release of sewage effluent, trade effluent or other contaminated discharges to ground if it is satisfied that it is not reasonable to make a connection to the public foul sewer. The developer would have to provide evidence of why the proposed development cannot

—————————————————————————————————————————————

3 The Environment Agency’s approach to groundwater protection, Environment Agency (2018). Accessed online at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/692989/Envirnm ent-Agency-approach-to-groundwater-protection.pdf on: 02/11/2018

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connect to the foul sewer in the planning application. This position will not normally apply to surface water run-off via sustainable drainage systems and discharges from sewage treatment works operated by sewerage undertakers with appropriate treatment and discharge controls. Deep infiltration systems (such as boreholes and shafts) are not generally accepted by the EA for discharge of sewage effluent as they bypass soil layers and reduce the opportunity for attenuation of pollutants. Discharges of surface water run-off to ground at sites affected by land contamination, or from sites for the storage of potential pollutants are likely to require an environmental permit. This could include sites such as garage forecourts and coach and lorry parks. These sites would be subject to a risk assessment with acceptable effluent treatment provided. Discharge of surface water Discharges of surface water runoff from roofs or from roads may not require a permit. However, they are still a potential source of groundwater pollution if they are not appropriately designed and maintained. Where infiltration SuDS schemes are proposed to manage surface runoff they should:  be suitably designed  meet Government non-statutory technical standards4 for sustainable drainage systems – these should be used in conjunction with the NPPF and PPG  and use a SuDS management treatment train A hydrogeological risk assessment is required where infiltration SuDS is proposed for anything other than clean roof drainage in a SPZ1. Source Protection Zones in Tandridge District The Source Protection Zones (SPZs) that are present in the study area are shown in Figure 4.1. They cover much of the north of Tandridge district and extend 2-3km south of the M25.

————————————————————————————————————————————— 4 Non-statutory technical standards for sustainable drainage systems, DEFRA (2015). Accessed online at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_da ta/file/415773/sustainable-drainage-technical-standards.pdf on: 07/11/2018

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Figure 4.1 Source Protection Zones in Tandridge

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Table 4.1 Development sites within Source Protection Zones Source Protection Sites Management advice / EA position statement Zone ENA08 G2 – Inside SPZ1 all sewage effluent discharges to ground must have an environmental permit. G4 – Inside SPZ1 the EA will object to any new trade effluent, storm overflow from sewage system or other significantly contaminated discharges to ground where the risk of groundwater pollution is high and cannot be adequately mitigated. G12 – Discharge of clean roof water to ground is acceptable both within and outside SPZ1, provided all roof water down-pipes are sealed against pollutants Zone 1 – entering the system from surface runoff, effluent Inner disposal or other forms of discharge. The method of Protection discharge must not create new pathways for Zone pollutants to groundwater or mobilise contaminant already in the ground. No permit is required if these criteria are met. G13 – Where infiltration SuDS are proposed for anything other than clean roof drainage in a SPZ1, a hydrogeological risk assessment should be undertaken, to ensure that the system does not pose an unacceptable risk to the source of supply.

SuDS schemes must be suitably designed. CAT007, CAT016, A hydrogeological risk assessment is not a CAT040, CAT044, requirement for SuDS schemes, however they should CAT079, CAT081, CMP1, still be “suitably designed”, for instance following best Zone 2 – CMP2, CMP4, CMP6, practice guidance in the CIRIA SuDS Design Manual. Outer ENA030, WAR005, Protection WAR011, WAR012, Zone WAR016, WAR019, WAR023, WAR036, WAR038, UCS02

UCS09, OXT016, OXTC01 A hydrogeological risk assessment is not a Zone 3 – GOD010, GOD021 requirement for SuDS schemes, however they should Total still be “suitably designed”, for instance following best Catchment practice guidance in the CIRIA SuDS Design Manual.

4.2 WINEP Schemes

4.2.1 Introduction The Water Industry National Environment Programme (WINEP) sets out the actions that the water companies need to complete to meet their environmental obligations which include measures to maintain or improve WFD status in watercourses and protect drinking water sources amongst many others. Water Cycle Study (Stage 3) 2018 40

There are a number of schemes within Tandridge, mostly aimed at reducing the levels of Phosphorus. Table 4.2 WINEP Schemes in Tandridge ID Scheme name Waterbody Driver 7TW300159 Burstow WwTW Burstow Stream Urban Wastewater Treatment Regulations - Improvement 7TW200169 Burstow WwTW Burstow Stream Urban Wastewater Treatment Regulations – Long term monitoring 7TW200185 Burstow WwTW Burstow Stream Urban Wastewater Treatment Regulations – Investigation 7TW200149 Burstow WwTW – Burstow Stream WFD (surface water) – BOD Standards Investigation investigation 7TW200150 Burstow WwTW – Burstow Stream WFD (surface water) – Ammonia standards Investigation investigation 7TW200156 Burstow WwTW Burstow Stream WFD (surface water) – Action to improve - Phosphorus 7SO200096 Eden Vale WwTW Eden Brook WFD (surface water) – Action to improve - Phosphorus 7SO200097 Edenbridge WwTW Lower Eden WFD (surface water) – Action to improve - Phosphorus 7SO200098 Felbridge WwTW Eden Brook WFD (surface water) – Action to improve - Phosphorus 7SO200102 Godstone WwTW Gibbs Brook WFD (surface water) – Action to improve - Phosphorus 7SO200107 Limpsfield and Upper Eden WFD (surface water) – Action Oxted WwTW to improve - Phosphorus 7SO200108 Lingfield WwTW Ray Brook WFD (surface water) – Action to improve - Phosphorus

When determining actions to improve or prevent deterioration of the water environment, consideration is given to the proportion each sector, business or individual contributes to the problem. Action to reduce pollutants is assigned on a “fair share” basis. Only the actions assigned to the water companies are assessed in this report. The Phase 2 study concluded that: The planned growth within Tandridge District and its neighbouring authorities can be accommodated without causing a deterioration in water quality for sanitary determinands and nutrients, so long as timely interventions to prevent deterioration are implemented by Thames Water, Southern Water and the Environment Agency. No additional phase 3 assessment of water quality impacts is required. However, in order to achieve improvements in the WFD status of watercourses in Tandridge, new permit levels have been set by the Environment Agency. The model used to set these permits did not take into account the level of growth that will occur if the Local Plan is delivered.

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The Water Quality assessment conducted in Phase 2 has therefore been repeated using the WINEP targets to set a new baseline, and then investigating the impact of growth on the ability to meet these targets. It should be noted that the water quality assessment in Phase 2 tested the scenario of all three Garden Community sites identified in the Phase 2 study being adopted, and so remains a robust analysis of the impact of growth on water quality. A detailed methodology for the water quality assessment can be found in the Phase 2 report.

4.2.2 Methodology A new SIMCAT model was provided by the Environment Agency (TH_postcal_M1_permit – MoleEden.dat) that contained any AMP5 or AMP6 schemes within the catchment. This was then updated to include the new Phosphorus limits at each WwTW, and the current permitted dry weather flow (DWF) presented in Table 4.3. This formed the WINEP PR19 baseline.

Table 4.3 WINEP PR19 baseline parameters WwTW Waterbody Water Current WINEP/PR19 quality permitted Phosphorus monitoring DWF limit (Mean point (m3/day) mg/l) Eden Vale Eden Brook WQ 2,524 0.3 PMLR0003 Edenbridge Lower Eden WQ 2,240 0.5 E0000811 Felbridge Eden Brook WQ 1,312 0.2* E0000860 Godstone Gibbs Brook WQ 1,202 0.25 E0000902 Limpsfield Upper Eden WQ 4,724 0.25 and Oxted E0000818 Lingfield Ray Brook WQ 3,656 0.2* E0000851 Burstow Burstow WQ 1,596 0.3 Stream PMLR0093 *In these cases, the WINEP limit is set at the TAL of 0.25 mg/l, however the required performance, to be met by ‘stretch’ as modelled is 0.2 mg/l. This limit should be used in this exercise

This model was then updated to include the post-development flows at each of the WwTW and re-run to assess the impact on Phosphorus levels downstream of the WwTW. Where a deterioration from the PR19 WINEP baseline was observed, the model was re-run to obtain permit values to achieve no deterioration from the baseline.

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4.2.3 Results

Table 4.4 Water quality modelling results and suggest permit level

WwTW Current Observed Future flow WINEP Post Deterioration Suggested permitted DWF (pre- (post- Baseline development from WINEP new permit DWF development) development) mean river mean river baseline to achieve (m3/day) (m3/day) (m3/day) quality d/s quality 0% Phosphorus Phosphorus deterioration (Mean d/s (Mean (mg/l) mg/l) mg/l) Eden Vale 2,524 1,884 2,223 0.297 0.297 0% N/A Edenbridge 2,240 1,948 2,074 0.16 0.16 0% N/A Felbridge 1,312 1,209 1,324 0.0625 0.0628 0.5% 0.199 Godstone 1,202 915 1,065 0.0768 0.0768 0% N/A Limpsfield 4,724 5,573 5,804 0.121 0.13 7.4% 0.228 and Oxted Lingfield 3,656 2,658 4,278 0.317 0.312 0.1% N/A Improvement Burstow 1,596 1,576 1,700 0.495 0.493 0.1% N/A Improvement Eden Vale WwTW is outside the study area and does not serve growth within Tandridge, however it is an important input to the catchment water quality model.

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At Eden Vale, Edenbridge and Godstone WwTW, the post-development flow is still within the permitted DWF, and so there is no predicted deterioration in water quality from the WINEP PR19 baseline. At Burstow and Lingfield WwTWs, the post development flow led to a predicted improvement against the WINEP PR19 baseline. This is because the discharge from the WwTW with the tightened permit applied results in a dilution of pollutants from upstream, and a lower overall concentration of Phosphorus downstream of the WwTW. At Felbridge WwTW, the post growth flow is likely to exceed the permitted flow by the end of the Local Plan period, which may cause a deterioration in water quality against the WINEP PR19 baseline. This could be prevented by tightening the permit. At Oxted WwTW the works is currently exceeding its permit due to infiltration. The post development flow (which uses the current observed plus the estimated additional flow from growth) is therefore well in excess of the permitted flow. This causes a predicted 7.4% deterioration from the WINEP PR19 baseline. This could be prevented by tightening the permit from 0.25 mg/l to 0.228 mg/l. This is less than the current “Technically Achievable Limit” (TAL) of 0.25 and would represent a “stretch” target. It should be noted that an infiltration reduction scheme has been included in Southern Water’s draft business plan submitted to Ofwat for the period 2020-2025 which would enable Southern Water to meet the forecast growth in the Oxted WwTW catchment. Should this scheme be approved, the post development flow would be substantially less, and this tightened permit may not be required. In addition to the setting of new permit levels, it may also be necessary to add offsetting proposals aimed at reducing the phosphorus load from other sources. Offsetting and stretch targets are a developing permitting approach in the country, used to back up specific conventional permit limits.

4.2.4 Conclusion At Felbridge and Oxted WwTWs, a tightening of the permit may be required in order to accommodate planned growth and allow the WINEP water quality improvement targets to be met. At other WwTWs in Tandridge, growth is not predicted to have an impact on the WINEP programme. The proposed permit levels shown are based on preliminary modelling and will be reviewed upon receipt of a formal permit variation application by the Environment Agency.

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5. Sources of funding

5.1 Water supply and wastewater infrastructure Water companies have a statutory duty to provide infrastructure to new developments so far as reasonably practicable. The source of funding for this infrastructure depends on the type. Local infrastructure which includes the connection of new properties into the water main or sewer network, provision of new public sewers and reinforcement of the existing network is paid for by developers through a new infrastructure charge. Site specific charges may also apply to cover the actual cost of the physical connection to the network and can vary according to the complexity of the connection, and the distance from the main or sewer. Strategic infrastructure which serves the wider community and includes wastewater treatment works, larger pumping stations and water quality improvement schemes is funded through the sewerage undertaker’s business plan. The transition between local and strategic infrastructure is usually at the terminal pumping station. Figure 5.1 and Figure 5.2 show a typical water and wastewater network. The dark green and brown shaded areas are likely to be covered by site specific charges, paid by the developer. The light green shading is covered by the infrastructure charge also paid by the developer. The pink shaded area represents strategic infrastructure funded through the water company’s investment plan. The diagrams were provided by Southern Water, but the process is similar in areas served by other companies.

Figure 5.1 Typical water supply infrastructure connections and strategic assets. (Source: Southern Water)

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Figure 5.2 Typical wastewater infrastructure connections and strategic assets (Source: Southern Water)

Table 5.1 Links to water company infrastructure charges for 2018/2019 Company Service Website https://www.waterplc.com/userfiles/file/ChargingArrange SES Water Water supply ments2018-19.pdf Southern https://www.southernwater.co.uk/media/default/PDFs/ne Wastewater Water w-connection-charging-arrangements-18-19.pdf Thames https://developers.thameswater.co.uk/New-connection- Wastewater Water charging (Links correct 12/11/2018)

5.2 Developer Contributions and Utility Companies Developments with planning permission have a right to connect to the public water and sewerage systems, although this doesn’t preclude the requirement to ensure capacity exists to serve a development. Developers may either requisition a water supply connection or sewerage system, or self-build the assets and offer these for adoption by the water company or sewerage undertaker. Self-build and adoption are usually practiced for assets within the site boundary, whereas requisitions are normally used where an extension of upgrading the infrastructure requires construction on third party land. The cost of requisitions is shared between the water company and developer as defined in the Water Industry Act 1991.

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Where a water company is concerned that a new development may impact upon their service to customers or the environment (for example by causing foul sewer flooding or pollution) they may request the LPA to impose a Grampian condition, whereby the planning permission cannot be implemented until a third-party action to secure necessary upgrading or contributions. The above arrangements are third party transactions because the Town and Country Planning Act Section 106 agreements and Community Infrastructure Levy agreements may not be used to obtain funding for water or wastewater infrastructure.

5.3 Water quality improvements Where a flow permit needs to be increased in order to accommodate growth, and upgrades to the treatment processes are required in order to prevent a deterioration in water quality, these upgrades are usually funded through the water company’s business plan on a 5-year cycle.

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6. Summary and recommendations

6.1 Summary of phase 3 detailed study The phase 3 scoping water cycle study has been carried out with cooperation with SES Water, Southern Water and Thames Water and the Environment Agency. Section 3summarises the growth that is forecast to be delivered in each wastewater catchment, alongside any infrastructure that may be required to overcome constraints identified in the Phase 2 study. An assessment of the impact of growth on the ability to meet the proposed PR19 WINEP water quality targets is presented in 4.2. This found that in order to accommodate growth, and meet the WINEP targets, a tighter permit may be required at Felbridge and Oxted WwTWs, although in the case of Oxted, the need for a tighter permit may be offset by an infiltration reduction scheme. Section 12.2 of the Phase 2 study summarises the water cycle study recommendations. In addition to this, the Phase 3 study makes the following recommendations:  Tandridge District Council should discuss the phasing of developments within the Burstow WwTW catchment with Thames Water to ensure that capacity is available to serve this growth, as no upgrade scheme is currently defined.  Tandridge District Council should liaise with Southern Water to ensure the phasing of development within the Oxted catchment is line with capacity at Oxted WwTW. Southern Water should also discuss the impact of the infiltration reduction scheme in this catchment with the Environment Agency to understand the requirement for a tighter Phosphorus permit.  A policy should be included in the Local Plan safeguarding land around Lingfield WwTW for upgrades at this WwTW to allow capacity beyond the Local Plan period as the South Godstone Garden Community Site expands.

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Appendices

A Site Tracker Spreadsheet

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