Stoke-on-Trent City Council Strategic Flood Risk Assessment for Local Development Framework Level 1 Volume 1 - FINAL July 2008 Halcrow Group Limited Strategic Flood Risk Assessment Stoke-on-Trent City Council Strategic Flood Risk Assessment Stoke-on-Trent City Council Stoke-on-Trent City Council Strategic Flood Risk Assessment for Local Development Framework Level 1 Volume 1 - FINAL Contents Amendment Record This report has been issued and amended as follows: Issue Revision Description Date Signed 1 Draft Report 12/12/07 RD 2 Final Report 07/07/08 RD Prepared by: Michael Green/Caroline Mills Draft: 12/12/07 Final: 15/05/08 Checked by: Beccy Dunn Draft: 12/12/08 Final: 07/07/08 Approved by: John Parkin Draft: 12/12/08 Final: 07/07/08 Strategic Flood Risk Assessment Stoke-on-Trent City Council This page is left intentionally blank Strategic Flood Risk Assessment Stoke-on-Trent City Council Contents Contents.................................................................................................................................................1 List of Tables & Figures .......................................................................................................................3 Executive Summary ..............................................................................................................................5 1 Introduction...................................................................................................................................7 1.1 Terms of Reference ...................................................................................................................7 1.2 Project Aims ...............................................................................................................................7 1.3 Project Objectives ......................................................................................................................7 1.4 Project Deliverables ...................................................................................................................8 1.5 Outcomes of the SFRA Process ................................................................................................8 1.6 SFRA Context ..........................................................................................................................10 1.7 The Study Area ........................................................................................................................11 2 Planning Context........................................................................................................................15 2.1 Introduction ..............................................................................................................................15 2.2 Planning Policy Framework .....................................................................................................15 2.3 National Planning Policy ..........................................................................................................15 2.4 Regional Planning Policy .........................................................................................................17 2.5 Local Planning Policy...............................................................................................................18 3 Study Methodology ....................................................................................................................21 3.1 Level 1 SFRA Methodology .....................................................................................................21 3.2 Need for a Level 2 SFRA .........................................................................................................21 3.3 Technical Background..............................................................................................................22 3.4 Environment Agency Flood Zone Maps...................................................................................23 4 Flood Risk in the Study Area ....................................................................................................25 4.1 Approach to Data Gathering ....................................................................................................25 4.2 Historical Flooding....................................................................................................................25 4.3 Fluvial Flood Risk in Stoke-on-Trent as defined by the Flood Zone Maps..............................26 4.4 Issues With Existing Flood Zone Maps....................................................................................26 4.5 Flooding from Other Sources...................................................................................................28 5 Strategic Flood Risk Mapping...................................................................................................33 5.1 Strategic Flood Risk Maps .......................................................................................................33 5.2 Climate Change Maps..............................................................................................................34 6 Flood Warning Systems and Flood Risk Management Measures.........................................37 6.1 Flood Management ..................................................................................................................37 6.2 Flood Defences........................................................................................................................40 6.3 Culverts ....................................................................................................................................41 6.4 Residual Risk ...........................................................................................................................51 1 Strategic Flood Risk Assessment Stoke-on-Trent City Council 6.5 Storage Areas ..........................................................................................................................52 6.6 Existing Flood Warning System ...............................................................................................52 6.7 Flood Response Plan...............................................................................................................54 7 Flood Risk Management Policy Considerations .....................................................................57 7.1 Overview ..................................................................................................................................57 7.2 Policy Considerations...............................................................................................................57 7.3 Relevant Environment Agency policies from CFMPs ..............................................................59 7.4 Development Control Policies..................................................................................................59 7.5 Sensitive Development Locations............................................................................................61 8 Guidance on the Application of the Sequential Test..............................................................63 8.1 Step One: Strategic Overview of flood risk across all potential development areas ...............63 8.2 Step Two: Flood Risk Issues in Zone 1 ...................................................................................63 8.3 Step Three: Sequential Test in Zones 2 and 3 ........................................................................64 9 Guidance for Developers...........................................................................................................65 9.2 Raised Floor Levels and Basements (Freeboard) ...................................................................68 9.3 Developer Contributions...........................................................................................................69 10 Guidance for the Application of Sustainable Drainage Systems ..........................................71 10.1 Introduction ..............................................................................................................................71 10.2 Types of SUDS Systems..........................................................................................................71 10.3 Application of SUDS for Stoke-on-Trent City Council..............................................................72 11 Summary and Recommendations ............................................................................................75 11.1 Summary of Flood Risk Issues ................................................................................................75 11.2 Summary of Flood Zone Data Issues ......................................................................................76 11.3 Summary of Climate Change Impacts .....................................................................................76 11.4 Site Allocation Process ............................................................................................................77 11.5 Council Policy...........................................................................................................................78 11.6 Environment Agency Policies Relevant to the Council ............................................................79 11.7 Emergency Planning................................................................................................................79 11.8 General Recommendations .....................................................................................................79