Strategic Flood Risk Assessment for Greater Manchester
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Strategic Flood Risk Assessment for Greater Manchester Sub-Regional Assessment “Living Document” – August 2008 Association of Greater Manchester Authorities Strategic Flood Risk Assessment Sub-Regional Assessment Revision Schedule Strategic Flood Risk Assessment for Greater Manchester – Sub-Regional Report August 2008 Rev Date Details Prepared by Reviewed by Approved by 01 August 2007 DRAFT Michael Timmins Jon Robinson David Dales Principal Flood Risk Associate Director Specialist Peter Morgan Alan Houghton Planner Head of Planning North West 02 November DRAFT FINAL Michael Timmins Jon Robinson David Dales 2007 Principal Flood Risk Associate Director Specialist Peter Morgan Alan Houghton Planner Head of Planning North West 03 June 2008 ISSUE Gemma Costin Michael Timmins David Dales Flood Risk Specialist Principal Flood Risk Director Specialist Fay Tivey Flood Risk Specialist Peter Richards Anita Longworth Planner Principal Planner 04 August 2008 FINAL Fay Tivey Michael Timmins David Dales Flood Risk Specialist Principal Flood Risk Director Specialist Scott Wilson St James's Buildings, Oxford Street, Manchester, This document has been prepared in accordance with the scope of Scott Wilson's M1 6EF, appointment with its client and is subject to the terms of that appointment. It is addressed United Kingdom to and for the sole and confidential use and reliance of Scott Wilson's client. Scott Wilson accepts no liability for any use of this document other than by its client and only for the purposes for which it was prepared and provided. No person other than the client may copy (in whole or in part) use or rely on the contents of this document, without the prior Tel: +44 (0)161 236 8655 written permission of the Company Secretary of Scott Wilson Ltd. Any advice, opinions, Fax: +44 (0)161 228 2581 or recommendations within this document should be read and relied upon only in the context of the document as a whole. The contents of this document do not provide legal or tax advice or opinion. © Scott Wilson Ltd 2008 www.scottwilson.com Association of Greater Manchester Authorities Strategic Flood Risk Assessment Sub-Regional Assessment Table of Contents Abbreviations .............................................................................................. iv Glossary....................................................................................................... v 1 Executive Summary .......................................................................... 1 1.1 The Greater Manchester SFRA ...................................................................................... 1 1.2 A “Living Document” ....................................................................................................... 2 1.3 The Sub-Regional SFRA in the Context of PPS25.......................................................... 2 1.4 The SFRA Methodology.................................................................................................. 3 1.5 Key Stakeholders & Information Provided....................................................................... 3 1.6 Development & Policy Context........................................................................................ 5 1.6.1 Anticipated Development Patterns...................................................................................................6 1.6.2 Anticipated Quantum of Proposed Development.............................................................................6 1.7 Flood Risk ...................................................................................................................... 7 1.7.1 Flooding from Rivers........................................................................................................................8 1.7.2 Flooding from the Land ....................................................................................................................9 1.7.3 Flooding from Sewers ......................................................................................................................9 1.7.4 Manmade/Artificial Flooding...........................................................................................................10 1.7.5 Flooding from Groundwater ...........................................................................................................10 1.7.6 Historical Flooding..........................................................................................................................11 1.8 Climate Change and Future Flood Risk ........................................................................ 11 1.9 Flood Risk Mitigation and Management........................................................................ 12 1.10 Sub-Regional Strategic Overview ................................................................................. 13 1.10.1 Consequences of Upstream and Downstream Development........................................................13 1.11 Potential Conflicts between Development & the PPS25 Sequential Test ...................... 15 1.12 Properties and Populations Affected by Flooding.......................................................... 15 1.13 Strategic Flood Risk Mitigation...................................................................................... 16 1.13.1 Upstream storage...........................................................................................................................16 1.13.2 Sustainable Drainage Systems (SuDS) .........................................................................................17 1.14 Conclusions & Recommendations ................................................................................ 17 2 Introduction & Methodology............................................................. 19 2.1 The Greater Manchester SFRA .................................................................................... 20 2.2 SFRA Aims & Objectives .............................................................................................. 22 2.3 SFRA - a “Living Document” ......................................................................................... 23 2.4 The Sub-Regional SFRA in the Context of PPS25........................................................ 23 2.5 The SFRA Structure & Approach.................................................................................. 27 2.5.1 Development & Policy Context and Flood Risk Review ................................................................28 2.5.2 Strategic Overview of Flood Risk...................................................................................................29 2.6 Data Collection and Stakeholder Consultation.............................................................. 29 FINAL Report August 2008 i Association of Greater Manchester Authorities Strategic Flood Risk Assessment Sub-Regional Assessment 2.7 Key Stakeholders & Information Provided..................................................................... 29 2.7.1 Local Authorities.............................................................................................................................29 2.7.2 Environment Agency......................................................................................................................30 2.7.3 Highways Agency...........................................................................................................................30 2.7.4 United Utilities ................................................................................................................................30 2.7.5 British Waterways ..........................................................................................................................31 2.7.6 Manchester Ship Canal Company .................................................................................................32 2.7.7 Other Information Sources.............................................................................................................33 2.8 Data Review ................................................................................................................. 35 2.9 Data Gaps and Confidence........................................................................................... 35 3 Development and Policy Context..................................................... 39 3.1 Policy Context............................................................................................................... 39 3.1.1 European Policy.............................................................................................................................39 3.1.2 National Policy ...............................................................................................................................41 3.1.3 Regional Policy ..............................................................................................................................45 3.1.4 Anticipated Regional Development Patterns .................................................................................48 3.1.5 Local Policy ....................................................................................................................................53 3.1.6 Local Development Frameworks ...................................................................................................53 4 Flood Risk ....................................................................................... 55 4.1 Hydrological Summary.................................................................................................