Stage 2: Detailed Water Cycle Study Update Final Report December 2014 Prepared for: Huntingdonshire District Council UNITED KINGDOM & IRELAND Huntingdonshire District Council — Stage 2 Detailed Water Cycle Study REVISION SCHEDULE Rev Date Details Prepared by Reviewed by Approved by 1 May 2012 Draft Stage 2 WCS Report Gemma Hoad Carl Pelling Jon Robinson Water Scientist Principal Technical Director Consultant 2 September Final Draft Stage 2 WCS Gemma Hoad Carl Pelling Jon Robinson 2012 Report Water Scientist Principal Technical Director Consultant 3 November Final Stage 2 WCS Report Gemma Hoad Carl Pelling Jon Robinson 2012 Water Scientist Principal Technical Director Consultant 4 December Draft Stage 2 Update WCS Craig Boorman Carl Pelling Carl Pelling 2013 Report Graduate Principal Principal Consultant Hydrologist Consultant Gemma Hoad Water Scientist 5 September Final Draft Stage 2 Update Craig Boorman Carl Pelling Carl Pelling 2014 WCS Report Graduate Associate Associate Director Hydrologist Director Gemma Hoad Water Scientist 6 December Final Stage 2 Update WCS Craig Boorman Carl Pelling Carl Pelling 2014 Report Graduate Associate Associate Director Hydrologist Director Gemma Hoad Water Scientist URS Scott House Alençon Link Basingstoke Hants RG21 7PP 01256 310200 STAGE 2: DETAILED WCS UPDATE Final report ii Huntingdonshire District Council — Stage 2 Detailed Water Cycle Study TABLE OF CONTENTS TABLE OF CONTENTS ......................................................................III NON-TECHNICAL SUMMARY ............................................................ V 1 INTRODUCTION ................................................................1 1.1 Study Need and Drivers ...................................................1 1.2 WCS History ......................................................................1 1.3 Stage 2 – Study Governance ...........................................1 1.4 Stage 2 WCS Scope ..........................................................2 1.5 Study Drivers ....................................................................2 1.6 Water Use – Key Assumption ..........................................4 1.7 Report Structure ...............................................................4 2 PROPOSED GROWTH ......................................................5 2.1 Preferred Growth Strategy ...............................................5 2.2 Housing ..............................................................................5 2.3 Alconbury Airfield .............................................................6 3 WASTEWATER TREATMENT ASSESSMENT ................7 3.1 Wastewater Treatment Assessment Approach .............7 3.2 Wastewater Treatment Assessment – Results ........... 11 3.3 Wastewater assessment - Ecological Appraisal ........ 21 3.4 Impacts on the Ouse Washes SAC/SPA/Ramsar site/SSSI.......................................................................... 21 3.5 Impacts on Portholme SAC/SSSI ................................. 24 3.6 Impacts on the Nene Washes SAC/SPA/SSSI/Ramsar site ................................................................................... 25 3.7 Impacts on Berry Fen SSSI ........................................... 25 3.8 Impacts on Little Paxton Pits SSSI .............................. 26 3.9 Impacts on ecology outside designated sites ............ 26 3.10 Ecological opportunities associated with WwTWs .... 27 3.11 Climate Change Sensitivity – Water Quality ............... 28 3.12 Wastewater Summary ................................................... 31 4 WATER SUPPLY STRATEGY........................................ 32 4.1 Introduction .................................................................... 32 4.2 Water Resource Planning ............................................. 33 4.3 Planned Water Availability Summary .......................... 35 4.4 Water Efficiency Plan .................................................... 37 4.5 Drivers and Justification for Water Efficiency ............ 37 4.6 Policy and Legislation Drivers ..................................... 37 STAGE 2: DETAILED WCS UPDATE Final report iii Huntingdonshire District Council — Stage 2 Detailed Water Cycle Study 4.7 Water Neutrality ............................................................. 39 4.8 Water Supply and Climate Change Adaption ............. 52 5 SETTLEMENT AREA ASSESSMENTS ......................... 54 5.1 Introduction .................................................................... 54 5.2 Settlement Areas in Huntingdonshire ......................... 54 5.3 Site Specific Assessment Methodologies ................... 56 5.4 Ecological Opportunities associated with Development Areas ............................................................................... 59 5.5 Settlement Area 1 – Huntingdon (including Buckden, Godmanchester, Brampton, Offord d’Arcy) ................ 60 5.6 Settlement Area 2 – St Ives (including Fenstanton) ... 67 5.7 Settlement Area 3 – St Neots (including Little Paxton)72 5.8 Settlement Area 4 – Ramsey (including Somersham, Warboys)......................................................................... 77 5.9 Settlement Area 5 – Yaxley (including Stibbington, Holme, Sawtry) ............................................................... 85 5.10 Settlement Area 6 – Kimbolton .................................... 92 5.11 Water Cycle Constraints ............................................... 92 6 RECOMMENDATIONS AND POLICY ............................ 95 6.1 Introduction .................................................................... 95 6.2 Recommendations for Policy Development ............... 95 APPENDIX 1: LEGISLATIVE DRIVERS ........................................... 99 APPENDIX 2: WWTW CAPACITY ASSESSMENT RESULTS ...... 102 APPENDIX 3: FEH WORKSHEETS ................................................ 108 APPENDIX 4: STATUTORY DESIGNATED SITES DETAIL ......... 109 APPENDIX 5: WATER NEUTRALITY............................................. 117 LIMITATIONS .................................................................................. 138 STAGE 2: DETAILED WCS UPDATE Final report iv Huntingdonshire District Council — Stage 2 Detailed Water Cycle Study NON-TECHNICAL SUMMARY The district of Huntingdonshire is expected to experience a significant increase in housing provision over the period to 2036. This growth represents a challenge in ensuring that both the water environment and water services infrastructure has the capacity to sustain this level of growth and development proposed. A Detailed (Stage 2) Water Cycle Study was initially completed in 2012 based on preferred growth areas identified in the Huntingdonshire District Council’s adopted Core Strategy to 2026. An update was undertaken over 2013 to 2014 for additional growth over a longer plan period to 2036 as reported in this WCS document. Information has been used to determine how the water cycle constraints may relate to potential development sites within the settlements, if and how the constraints can be resolved and how they may impact on phasing of development over the plan period to 2036. Furthermore, it provides a detailed suggested approach to the management and use of water which demonstrates ways to ensure that the sustainability of the water environment in the study area is not compromised by growth. An updated Detailed Water Cycle Strategy is presented for the District as a whole and for each of the main growth settlements. The Wastewater Strategy Wastewater Treatment Capacity The table below provides an indication of the Wastewater Treatment Works (WwTWs) which are unable to accept any additional growth, and which have available capacity. SUMMARY OF WWTW AVAILABLE CAPACITY WwTW Catchment Phasing of Development Brampton Capacity for planned growth with some spare capacity for further growth Buckden Capacity for planned growth only Holme Capacity for planned growth with some spare capacity for further growth Huntingdon1 WwTW at consent limit after 2021 based on 2013 planned trajectory Oldhurst WwTW at consent limit Kimbolton Capacity for planned growth with some spare capacity for further growth Peterborough Capacity for planned growth – capacity for further growth is dependent on levels of growth outside of the District. Ramsey WwTW at consent limit 1 Including housing and employment growth at Alconbury Airfield site as well as RAF Wyton. STAGE 2: DETAILED WCS UPDATE Final report v Huntingdonshire District Council — Stage 2 Detailed Water Cycle Study SUMMARY OF WWTW AVAILABLE CAPACITY WwTW Catchment Phasing of Development Sawtry Capacity for planned growth with some spare capacity for further growth Stibbington Capacity for planned growth with some spare capacity for further growth Somersham WwTW at consent limit St Ives Capacity for planned growth with some spare capacity for further growth St Neots WwTW at consent limit The Detailed study has shown that several WwTWs have capacity to accept wastewater flow from the proposed growth without the need for improvements to treatment infrastructure. This is the case for Brampton, Buckden, Holme, Kimbolton, Peterborough, Sawtry, Stibbington and St Ives. Growth is not constrained by wastewater treatment in these locations. WwTWs at Oldhurst, Ramsey, Somersham and St Neots are shown to already be at their limit of consent with current housing levels. Huntingdon WwTW only has capacity up to 2021 based on estimated growth trajectories from 2013, or 5,100 dwellings. Therefore solutions are required in order to accommodate growth