Northumberland County Council Level 1 Strategic Flood Risk Assessment
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Northumberland County Council Level 1 Strategic Flood Risk Assessment Final Report September 2010 Prepared for: Northumberland County Council Level 1 Strategic Flood Risk Assessment Revision Schedule Level 1 Strategic Flood Risk Assessment Final Report September 2010 Rev Date Details Prepared by Reviewed by Approved by 01 August 2009 Interim Draft Level 1 Gemma Costin Jon Robinson Les Orange SFRA Assistant Flood Risk Associate Director Associate Specialist 02 November 2009 Draft Level 1 SFRA Gemma Costin Jon Robinson Les Orange Assistant Flood Risk Associate Director Associate Specialist 03 April 2010 Final Draft Srimali Abeyrathne Sally Atkinson Les Orange Graduate Engineer Principal Engineer Associate 04 August 2010 Final Report Srimali Abeyrathne Sally Atkinson Les Orange Graduate Engineer Principal Engineer Associate 05 September 2010 Final Report Srimali Abeyrathne Sally Atkinson Les Orange Graduate Engineer Principal Engineer Associate Scott Wilson Victoria House 159 Albert Road This document has been prepared in accordance with the scope of Scott Wilson's appointment with its client and is subject to the terms of that appointment. 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The contents of this document are not to be Fax 01642 223582 construed as providing legal, business or tax advice or opinion. © Scott Wilson Group PLC 2009 www.scottwilson.com S106308 September 2010 i Northumberland County Council Level 1 Strategic Flood Risk Assessment Table of Contents Abbreviations..................................................................................................................iv Executive Summary .......................................................................................................vi 1 Introduction.........................................................................................................1 1.1 Background ......................................................................................................................................1 1.2 The Northumberland SFRA..............................................................................................................2 1.3 The SFRA Structure.........................................................................................................................2 1.4 The SFRA Aims & Purpose..............................................................................................................3 2 Northumberland County Council.......................................................................5 2.1 Study Area........................................................................................................................................5 2.2 Administrative Bodies.......................................................................................................................6 2.3 Historical Flooding............................................................................................................................7 2.4 Existing Assessment of Flood Risk..................................................................................................7 2.5 Flood Sources ..................................................................................................................................7 2.6 Flood Risk Management ................................................................................................................15 2.7 Flooding Mechanisms ....................................................................................................................19 2.8 Potential Development Pressures..................................................................................................20 2.9 Climate Change and Future Flood Risk.........................................................................................24 3 Policy Review....................................................................................................26 3.1 Planning Policy...............................................................................................................................26 3.2 European Policy .............................................................................................................................27 3.3 National Planning Policy ................................................................................................................29 3.4 Regional Planning Policy ...............................................................................................................33 3.5 Local Planning Policy.....................................................................................................................35 3.6 Non-Statutory National Planning Documents ................................................................................42 3.7 Catchment Flood Management Plans............................................................................................44 3.8 Flood Risk ......................................................................................................................................47 3.9 Sustainable Drainage Systems......................................................................................................48 3.10 Water Environment ........................................................................................................................49 4 Level 1 SFRA.....................................................................................................50 4.1 Objective ........................................................................................................................................50 4.2 Tasks..............................................................................................................................................50 4.3 Stakeholders ..................................................................................................................................50 4.4 Data/Information Collected.............................................................................................................51 4.5 GIS, Flood Mapping and Application .............................................................................................52 4.6 Flood Risk Review Summary.........................................................................................................59 5 The Sequential Test ..........................................................................................62 5.1 The Sequential Approach...............................................................................................................62 5.2 Using the SFRA to Apply the Sequential Test ...............................................................................63 5.3 Recommended Stages for Application of the Sequential Test ......................................................68 5.4 Using the SFRA Maps, Data and GIS Layers................................................................................69 S106308 September 2010 ii Northumberland County Council Level 1 Strategic Flood Risk Assessment 6 Site Specific Flood Risk Assessment Guidance............................................72 6.1 Introduction.....................................................................................................................................72 6.2 Flood Risk Assessment Guidance .................................................................................................73 6.3 Residual Risk Management ...........................................................................................................75 7 Recommendations for Level 2 SFRAs ............................................................84 7.1 What is a Level 2 SFRA? ...............................................................................................................84 7.2 Level 2 SFRA Approach.................................................................................................................84 7.3 NCC Level 2 SFRA Requirements.................................................................................................85 References .....................................................................................................................86 National Policy & Guidance Documents........................................................................................................86 Regional and Local Policy and Guidance Documents ..................................................................................87 Appendix A: Historical Flood Events Appendix B: SFRA Mapping Appendix B - 1: Detailed Maps Covering NCC Administrative Area Appendix B - 2: Flood Zone Confidence Maps Appendix B - 3: Areas Susceptible to Surface Water Flooding Maps Appendix B - 4: Northumbrian Water DG5 Sewer Flooding Map Appendix C: SuDS Appendix D: Data Register Appendix E: Contacts Appendix F: GIS Data Appendix G: Groundwater Vulnerability and Geology Mapping Appendix H: SFRA Maintenance and Update Appendix I: