INSERT YOUR PICTURE(S) IN THIS CELL Weir and Lock Cottage on the River Stour, Nayland Babergh Water Cycle Study Stage1/2 Babergh District Council July 2011 Final Report v2 9V9327 5th Floor, Radcliffe House Blenheim Court Solihull B91 2AA United Kingdom +44 (0)121 709 6520 Telephone Fax [email protected] E-mail www.royalhaskoning.com Internet Document title Babergh Water Cycle Study Stage1/2 Document short title Babergh WCS Status Final Report v2 Date July 2011 Project name Babergh Water Cycle Study Project number 9V9327 Client Babergh District Council Reference 9V9327/R00003/303671/Soli Drafted by R Ranger Checked by F Ogunyoye Date/initials check 27th June 2011 Approved by F Ogunyoye Date/initials approval 27th June 2011 CONTENTS Page 1 INTRODUCTION 1 1.1 General Overview 1 1.2 Scope 1 1.3 Objectives of the Water Cycle Study 2 1.4 Guidance on the use of this Study 2 2 DATA COLLECTION AND METHODOLOGY 5 2.1 Overview 5 2.2 Data Collection 5 2.3 Housing and Employment Growth 6 2.4 Water Resources and Supply 9 2.5 Wastewater Treatment and Collection 15 2.6 Water Quality and the Environment 19 2.7 Flood Risk 26 2.8 Demand Management and SUDS 29 2.9 Data Limitations 32 3 GROWTH OPTION 1: CURRENT SITUATION 33 3.1 Introduction 33 3.2 Water Resources and Supply 33 3.3 Wastewater Treatment and Collection 33 3.4 Water Quality and the Environment 36 3.5 Flood Risk 42 3.6 Demand Management and SUDS 45 3.7 Summary 49 4 OPTIONS FOR GROWTH 51 4.1 Introduction 51 4.2 Water Resources and Supply 51 4.3 Wastewater Treatment and Collection 55 4.4 Water Quality and the Environment 65 4.5 Flood Risk 68 4.6 Demand Management and SUDS 75 4.7 Summary 75 5 GROWTH OPTION 5: MAXIMUM CAPACITY 79 5.1 Water Resources and Supply 79 5.2 Wastewater Treatment and Collection 80 5.3 Water Quality and the Environment 82 5.4 Flood Risk 83 5.5 Demand Management and SUDS 84 5.6 Summary 85 Babergh WCS 9V9327/R00003/303671/Soli Final Report v2 -i- July 2011 6 CONSTRAINTS MATRIX AND CONCLUSIONS 87 6.1 Development Location Specific Conclusions and Timelines 87 6.2 Recommendations 93 6.3 Future Updates 94 7 GUIDANCE DOCUMENTS 95 7.1 Flood Risk 95 7.2 Demand Management 97 7.3 SUDS 99 7.4 Developer Contributions 109 7.5 Water Industry Funding 114 9V9327/R00003/303671/Soli Babergh WCS July 2011 ii Final Report v2 APPENDICES Appendix A - Figures Appendix B - Data Register Appendix C - Growth Trajectories Appendix D - RBMP Summary Appendix E - WwTW Flow Data Appendix F - Indicative Permit Consents Appendix G - Constraints Matrix Appendix H - FRA Guidance Leaflet TABLES Table 2.1 - Proposed Locations for Growth within Babergh District Table 2.2 - Potential Growth Area WRZ and PZ Table 2.3 - Environment Agency Water Resource Availability Status Categories Table 2.4 - Water Usage Design Flows Table 3.1 - WwTW Current Capacity Table 3.2 - Current WFD Objectives for Principle Rivers within Babergh District (as reported in the Anglian RBMP, December 2009) Table 3.3 - Current Condition of Environmentally Designated Sites Table 3.4 - Current Flood Risk to Babergh Key Settlements Table 3.5 - Settlement Specific SUDS Restrictions Table 3.6 - Summary of Current Situation Table 4.1 - Summary of Growth Options Table 4.2 - Planning Zone Water Supply Deficits Table 4.3 - Planned Mitigation Measures Table 4.4 - Summary of Settlements within each WwTW Catchment Table 4.5 - Growth Option 2, Residential Development WwTW Capacity (inc. commitments & windfalls) Table 4.6 - Growth Option 3, Residential Development WwTW Capacity (inc. commitments & windfalls) Table 4.7 - Growth Option 2, Residential and Employment Development WwTW Capacity (including commitments & windfalls) Table 4.8 - Growth Option 3, Residential and Employment Development WwTW Capacity (including commitments & windfalls) Table 4.9 - Growth Option 4, Residential Development WwTW Capacity (including commitments & windfalls) Table 4.10 - Growth Option 4, Residential and Employment Development WwTW Capacity (inc. commitments & windfalls Table 4.11 - WwTWs Requiring an Increased CDWF or Experiencing Limited Headroom Within the Planning Period Table 4.12 - PPS25 Climate Change Allowances Table 4.13 - Potential Increase in River Flow as a Result of WwTW Discharge Table 4.14 - Key Settlements and Structures Located Downstream of WwTWs Table 4.15 - Impact of Flood Risk on Potential Development Locations Table 4.16 - Ability of WCS to Accommodate Growth Options 2 and 3 Table 5.1 - Maximum WwTW Capacity, Flow and Dwelling Numbers Babergh WCS 9V9327/R00003/303671/Soli Final Report v2 -iii- July 2011 Table 5.2 - Maximum Capacity of District for Development Outside Fluvial, Tidal and Surface Water Flood Zones Table 5.3 - Maximum Capacity of WCS Table 6.1 - RAG Key Table 6.2 - Ability of WCS to Accommodate Growth Options 2, 3 and 4 Table 6.3 - Mitigation Measures Required for WCS to Accommodate Growth Options 2, 3 and 4 Table 7.1 - Flood Risk Vulnerability and Flood Zone “Compatibility” (from PPS25) Table 7.2 - Applicable SUDS Techniques Based Upon Soil Type Table 7.3 - Applicable SUDS Techniques Based Upon GWV and SPZs Table 7.4 - Applicable SUDS Techniques as Single Components, Based Upon Drainage Area Table 7.5 - Applicable SUDS Techniques Based Upon Topography Table 7.6 - Applicable SUDS Techniques Based Upon Hydraulic Head Table 7.7 - Applicable SUDS Techniques Based Upon the Availability of Space Table 7.8 - Applicable SUDS Techniques Based Upon the Intended Use of the Land FIGURES Figure 1 - Study Area Figures 2a and 2b - Potential Development Locations Figure 3 - Environment Agency ‘Areas of Water Stress’ Figures 4a and 4b - Water Supply Figures 5a and 5b - Wastewater Treatment Works Figures 6a and 6b - Environmentally Designated Sites Figures 7a and 7b - Flood Risk Figure 8 - Groundwater Vulnerability Figure 9 - Source Protection Zones 9V9327/R00003/303671/Soli Babergh WCS July 2011 iv Final Report v2 EXECUTIVE SUMMARY Overview and Context i In April 2010 Royal Haskoning was appointed by Babergh District Council (hereafter “the Council”) to produce a Stage 2 Water Cycle Study. This Water Cycle Study considers the District as a whole, updating the findings of the Haven Gateway Water Cycle Study where appropriate. This report has been written to the specification of the Environment Agency’s Water Cycle Study guidance (version 4), being equivalent to an Outline/Detailed level study, and the requirements of the Brief. ii The report considers the following issues, addressing the constraints that they may pose to future development and, where applicable, discusses the improvements necessary to achieve the required level of development throughout the planning period, until 2031: • Water Resources and Supply; • Wastewater Collection and Treatment; • Water Quality and Environmental Issues; • Flood Risk; and • Demand Management and Sustainable Drainage Systems. iii This Water Cycle Study has been produced for the Council in consultation with the Environment Agency and AWS. Over the duration of the study much data has been requested, received and reviewed from the project consultees. The data included within the study was correct as of the start of May 2011. Due to the nature of this data and study, some of this information will become superseded fairly rapidly. Any limitations of the data are discussed further in the relevant sections of the report. Growth Options iv To assist the Council in determining the capacity of the water cycle for sustainable growth, the following five growth options have been considered within this Water Cycle Study: • Growth Option 1 - the current situation • Growth Option 2 - Former Regional Spatial Strategy Targets • Growth Option 3 - Draft Regional Spatial Strategy Review to 2031 • Growth Option 4 - Alternative Growth Scenarios • Growth Option 5 - the maximum capacity Babergh WCS 9V9327/R00003/303671/Soli Final Report v2 -v- July 2011 Assessment Water Resources and Supply v The status of water resources and supply has been assessed through consultation with Anglian Water Services and review of their Final Water Resources Management Plan, in addition to the Environment Agency’s relevant Catchment Abstraction Management Strategy reports. Wastewater Treatment and Network vi Raw data regarding the current and consented flows has been provided by AWS. This has been reviewed using a tool created by Royal Haskoning to assess if and when each Wastewater Treatment Works (WwTW) will exceed its consent. The tool also provides flow information to determine the new consent requirements for each Wastewater Treatment Works. Where a new consent is required, the impact of the new flow upon flood risk has been analysed. The capacity of the sewer network has been assessed through consultation with Anglian Water Services. Water Quality and Environmentally Designated Sites vii The location and status of nationally and internationally-designated sites within the District has been obtained and the current water quality status of the watercourses has been determined through consultation with the Environment Agency and a review of the Anglian River Basin Management Plan. The effect of development upon water quality has been assessed through calculations of Indicative Consent Limits undertaken by the Environment Agency for Ammonia, Biochemical Oxygen Demand and Phosphates. Through calculation of the required consent limits for these elements (both with and without development) assessment has been made as to whether the proposed growth will impact upon the required Water Framework Directive (WFD) targets and whether the required improvements are within the current “Economic Limit of Conventional Treatment”. It is the responsibility of the Environment Agency as the ‘competent authority’ to ensure the Directive is carried out, although it is also a requirement of Regulation 17 that all public bodies have regard to the RBMPs and their objectives.