Strategic Flood Risk Assessment
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Tameside Metropolitan Borough Council Tameside Level 1 Update and Level 2 Strategic Flood Risk Assessment March 2011 Prepared for Tameside Metropolitan Borough Council Tameside Level 1 Update and Level 2 Strategic Flood Risk Assessment Revision Schedule Tameside Level 1 Update and Level 2 Strategic Flood Risk Assessment October 2010 Rev Date Details Prepared by Reviewed by Approved by 01 July 2010 Draft Mark Crussell Michael Timmins Michael Timmins Assistant Flood Risk Principal Flood Risk Principal Flood Risk Specialist Specialist Specialist Alpha Robinson Principal Flood Risk Engineer Sam Rosillo Anita Longworth Graduate Planner Principal Planner 02 October 2010 Final Draft Alpha Robinson Michael Timmins Michael Timmins Principal Flood Risk Principal Flood Risk Principal Flood Risk Engineer Specialist Specialist Helen Burton Assistant Flood Risk Specialist 03 March 2011 Final Alpha Robinson Michael Timmins Michael Timmins Principal Flood Risk Principal Flood Risk Principal Flood Risk Engineer Specialist Specialist Ene Adanu Assistant Engineer Scott Wilson 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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Tel +44 (0)161 907 3500 © Scott Wilson Ltd 2011 Fax +44 (0)161 907 3501 www.scottwilson.com Tameside Metropolitan Borough Council Tameside Level 1 Update and Level 2 Strategic Flood Risk Assessment Table of Contents 1 Introduction.........................................................................................................1 1.1 Policy Context and Background.......................................................................................................1 1.2 Study Area .......................................................................................................................................2 1.3 Aims and Objectives of the Level 1 SFRA Update and Level 2 SFRA............................................3 2 Sequential Approach to Site Allocation............................................................5 2.1 The Sequential Test.........................................................................................................................5 2.2 Development Vulnerability ...............................................................................................................5 2.3 Flood Zone Definition .......................................................................................................................8 2.4 The Exception Test ..........................................................................................................................9 3 Planning Context ..............................................................................................11 4 SFRA Approach ................................................................................................12 4.1 General Approach ..........................................................................................................................12 4.2 Level 1 Update ...............................................................................................................................12 4.3 Level 2 SFRA Requirements .........................................................................................................13 4.4 Level 2 SFRA Output .....................................................................................................................18 5 Level 1 SFRA Update........................................................................................20 5.1 Flooding History .............................................................................................................................20 5.2 Level 1 Update of Fluvial Flooding across Tameside ....................................................................20 5.3 Pluvial Flood Risk (flooding from overland flow)............................................................................23 5.4 Sewer and Drainage Flood Risk ....................................................................................................25 5.5 Critical Drainage Areas ..................................................................................................................26 5.6 Flood Risk from Man-Made/Artificial Sources – Canals ................................................................28 5.7 Flood Risk from Man-Made/Artificial Sources – Reservoirs ..........................................................31 5.8 Groundwater Flood Risk ................................................................................................................33 6 Tameside Level 2 SFRA ...................................................................................36 6.1 Development Proposals in the Key Potential Development Areas................................................36 6.2 Level 2 Fluvial Flood Risk Assessment in Key Potential Development Areas ..............................36 6.3 Risk of Flooding from Other Sources.............................................................................................56 7 SFRA Policies and Flood Risk Management ..................................................59 7.2 District Wide SFRA Policies...........................................................................................................59 7.3 Specific SFRA Policies for the Potential Development Areas .......................................................62 7.4 Flood Risk Management Options...................................................................................................65 8 Site Specific Flood Risk Assessment Guidance............................................67 8.2 Application of the Sequential Approach.........................................................................................67 8.3 Building Design ..............................................................................................................................68 8.4 Surface Water Management ..........................................................................................................68 8.5 Pluvial Flood Risk...........................................................................................................................72 8.6 Flooding from Sewers and Drains..................................................................................................73 Tameside Metropolitan Borough Council Tameside Level 1 Update and Level 2 Strategic Flood Risk Assessment 8.7 Risk of flooding from Canals and Reservoirs.................................................................................73 8.8 Climate Change .............................................................................................................................73 8.9 Residual Risk Mitigation.................................................................................................................74 9 Conclusions and Recommendations ..............................................................78 9.1 Conclusions....................................................................................................................................78 9.2 Recommendations .........................................................................................................................79 Appendix 1 Maps Appendix 2 Summary of Planning Data Appendix 3 Flood Defence Inspection Report Figures Figure 4-1: Hierarchical Approach to Flood Risk......................................................................................12 Figure 5-1: Overview of watercourses in the borough. ............................................................................21 Figure 6-1: Model coverage and hydraulic structures modified in the combined model..........................37 Figure 6-2: Long section showing water levels along the Tame through Tameside................................44 Figure 6-3: Mossley Development Area 1% AEP and 0.1 % AEP Flood Outlines...................................46 Figure 6-4: Mossley Development Area Depth Hazard Map for the 1% AEP event ................................47 Figure 6-5: Mossley Development Area Depth Hazard Map for the 1% AEP plus climate change event ..................................................................................................................................................................48 Figure 6-6:Tame Valley: Ashton to Stalybridge and Shepley Development Area 1% AEP and 0.1 % AEP Flood Outlines ..........................................................................................................................................50 Figure 6-7: Tame Valley: Ashton to Stalybridge Corridor and Shepley Industrial Estates, Dukinfield Depth Hazard Map for the 1% AEP Event ...............................................................................................51