Milton Keynes Water Cycle Study FINAL DRAFT Milton Keynes Water Cycle Study Milton Keynes Council FINAL DRAFT November 2017 November 2017 AECOM Milton Keynes Water Cycle Study FINAL DRAFT Quality information Prepared by Checked by Approved by Bernadine Maguire Chris Gordon Carl Pelling Principal Flood Risk & Coastal Senior Environmental Engineer Associate Consultant Revision History Revision Revision date Details Authorized Name Position 1 19/09/2017 Draft for Client and Carl Pelling Associate Stakeholder comment 2 03/11/2017 Final incorporating Emily Craven Associate Client and Stakeholder comments Prepared for: Milton Keynes Council Prepared by: AECOM Limited Midpoint Alencon Link Basingstoke Hampshire RG21 7PP UK T: +44(0)1256 310200 aecom.com Job number: 60545995 Copyright © 2017 AECOM Limited. All Rights Reserved. This document has been prepared by AECOM Limited (“AECOM”) for sole use of our client (the “Client”) in accordance with generally accepted consultancy principles, the budget for fees and the terms of reference agreed between AECOM and the Client. Any information provided by third parties and referred to herein has not been checked or verified by AECOM, unless otherwise expressly stated in the document. No third party may rely upon this document without the prior and express written agreement of AECOM. November 2017 AECOM Milton Keynes Water Cycle Study FINAL DRAFT Table of Contents List of Acronyms ............................................................................................................................................... 1 Non-Technical Summary ................................................................................................................................... 2 Wastewater Strategy .............................................................................................................................. 2 Wastewater Treatment ........................................................................................................................... 2 Water Supply Strategy............................................................................................................................ 3 Overall Impact of Development ............................................................................................................... 3 1. Introduction ............................................................................................................................................ 4 1.1 Background................................................................................................................................. 4 1.2 WCS History ............................................................................................................................... 4 1.3 Study Governance....................................................................................................................... 4 1.4 WCS Scope ................................................................................................................................ 4 1.5 Key Assumptions and Conditions ................................................................................................. 5 1.5.1 Water Company Coverage........................................................................................................... 5 1.5.2 Water Use ................................................................................................................................... 5 1.5.3 Household Occupancy Rate ........................................................................................................ 6 1.5.4 Wastewater Treatment................................................................................................................. 6 1.6 Report Structure .......................................................................................................................... 6 2. Study Drivers ......................................................................................................................................... 8 2.1 OFWAT Price Review .................................................................................................................. 8 2.2 Water Framework Directive.......................................................................................................... 9 3. Proposed Growth ................................................................................................................................. 10 3.1 Preferred Growth Strategy .......................................................................................................... 10 3.2 Housing .................................................................................................................................... 11 3.3 Employment .............................................................................................................................. 11 4. Wastewater Treatment ......................................................................................................................... 12 4.1 Wastewater in the Borough ........................................................................................................ 12 4.2 Management of WRC Discharges .............................................................................................. 13 4.3 WFD Compliance ...................................................................................................................... 14 4.4 Habitats Directive ...................................................................................................................... 15 4.5 Wastewater Assessment Overview ............................................................................................ 16 4.5.1 Approach .................................................................................................................................. 16 4.5.2 Methodology ............................................................................................................................. 16 4.5.3 Assessment Results .................................................................................................................. 17 4.6 WRC Headroom Assessment .................................................................................................... 18 4.6.1 Available Permitted Headroom – Significant Growth ................................................................... 18 4.6.2 No available Permitted Headroom .............................................................................................. 19 4.6.3 Exceedance of Descriptive Permit .............................................................................................. 19 4.6.4 Summary .................................................................................................................................. 19 4.7 Water Quality Assessment ......................................................................................................... 21 4.7.1 Castlethorpe WRC .................................................................................................................... 21 4.7.2 Cotton Valley WRC .................................................................................................................... 23 4.7.3 Hanslope WRC ......................................................................................................................... 25 4.7.4 Olney WRC ............................................................................................................................... 26 4.8 Ecological Appraisal .................................................................................................................. 28 4.8.1 Impact on Designated Sites ....................................................................................................... 30 4.8.2 Impacts on Ecology outside Designated Sites ............................................................................ 31 4.8.3 Ecological Opportunities Associated with Proposed Development Locations................................ 31 4.9 Wastewater Summary ............................................................................................................... 31 4.10 Overall RAG Assessment .......................................................................................................... 32 5. Water Supply Strategy.......................................................................................................................... 34 November 2017 AECOM Milton Keynes Water Cycle Study FINAL DRAFT 5.1 Introduction ............................................................................................................................... 34 5.2 Abstraction Licensing Strategies ................................................................................................ 34 5.3 Water Resource Planning .......................................................................................................... 36 5.4 Water Resource Planning in the Borough ................................................................................... 36 5.5 Planned Water Availability Summary .......................................................................................... 36 5.5.1 Ruthamford South Water Resource Zone ................................................................................... 36 5.6 Demand for Water ..................................................................................................................... 37 5.7 Drivers and Justification