Warwickshire County Council Strategic Flood Risk Assessment for Local Development Framework Level 1 Volume 1 February 2008 Halcrow Group Limited Strategic Flood Risk Assessment Warwickshire County Council Strategic Flood Risk Assessment Warwickshire County Council Warwickshire County Council Strategic Flood Risk Assessment for Local Development Framework Level 1 Volume 1 Contents Amendment Record This report has been issued and amended as follows: Issue Revision Description Date Signed 1 Draft Report 06/12/07 RD 1 A Draft Report 28/01/08 RD 2 Final Report 18/02/08 RD 2 A Final Report 20/02/08 RD Strategic Flood Risk Assessment Warwickshire County Council Contents Contents.................................................................................................................................................1 Executive Summary ..............................................................................................................................4 1 Introduction...................................................................................................................................5 1.1 Terms of Reference ...................................................................................................................5 1.2 Project Aims ...............................................................................................................................5 1.3 Project Objectives ......................................................................................................................5 1.4 Project Deliverables ...................................................................................................................6 1.5 Outcomes of the SFRA Process ................................................................................................6 1.6 SFRA Context ............................................................................................................................9 1.7 The Study Area ........................................................................................................................10 2 Planning Context........................................................................................................................17 2.1 Introduction ..............................................................................................................................17 2.2 Planning Policy Framework .....................................................................................................17 2.3 National Planning Policy ..........................................................................................................17 2.4 Regional Planning Policy .........................................................................................................19 2.5 Local Planning Policy...............................................................................................................21 3 Minerals and Waste....................................................................................................................22 3.1 Introduction ..............................................................................................................................22 3.2 Context.....................................................................................................................................22 3.3 Mineral Extraction ....................................................................................................................22 3.4 Waste Sites ..............................................................................................................................23 4 Study Methodology ....................................................................................................................24 4.1 Level 1 SFRA Methodology .....................................................................................................24 4.2 Need for a Level 2 SFRA .........................................................................................................24 4.3 Technical Background..............................................................................................................25 4.4 Environment Agency Flood Zone maps...................................................................................26 5 Flood Risk in the Study Area ....................................................................................................27 5.1 Approach to Data Gathering ....................................................................................................27 5.2 Historical Flooding....................................................................................................................27 5.3 Fluvial Flood Risk in Warwickshire as defined by the Flood Zone maps.................................29 5.4 Flooding from Other Sources...................................................................................................36 1 Strategic Flood Risk Assessment Warwickshire County Council 6 Strategic Flood Risk Mapping...................................................................................................42 6.1 Strategic Flood Risk Maps .......................................................................................................42 6.2 Climate Change Maps..............................................................................................................45 7 Flood Warning Systems and Flood Risk Management Measures.........................................47 7.1 Flood Risk Management ..........................................................................................................47 7.2 Flood Defences........................................................................................................................56 7.3 Residual Risk ...........................................................................................................................60 7.4 Storage Areas ..........................................................................................................................61 7.5 Existing Flood Warning System ...............................................................................................62 7.6 Flood Response Plan...............................................................................................................66 8 Flood Risk Management Policy Considerations .....................................................................68 8.1 Overview ..................................................................................................................................68 8.2 Policy Considerations...............................................................................................................69 8.3 Development Control Policies..................................................................................................71 8.4 Council Specific Policy Issues .................................................................................................73 8.5 Avoiding Increased Flood Risk Elsewhere...............................................................................73 9 Guidance on the Application of the Sequential Test..............................................................75 9.1 Step One: Strategic Overview of flood risk across all potential development areas ...............75 9.2 Step Two: Flood Risk Issues in Zone 1 ...................................................................................75 9.3 Step Three: Sequential Test in Zones 2 and 3 ........................................................................76 10 Guidance for Developers...........................................................................................................77 10.2 Developer Contributions ......................................................................................................81 11 Guidance for the Application of Sustainable Drainage Systems ..........................................82 11.1 Introduction ..........................................................................................................................82 11.2 Types of SUDS Systems .....................................................................................................82 11.3 Application of SUDS for Minerals and Waste Sites.............................................................83 11.4 Application of SUDS for North Warwickshire Borough Council...........................................84 11.5 Application of SUDS for Nuneaton & Bedworth Borough Council.......................................85 11.6 Application of SUDS for Rugby Borough Council................................................................85 11.7 Application of SUDS for Warwick District Council ...............................................................86 11.8 Application of SUDS for Stratford-on-Avon District Council ................................................87 12 Recommendations .....................................................................................................................89 12.1 Site Allocation Process ........................................................................................................89 12.2 Council Policy ......................................................................................................................89 2 Strategic Flood Risk Assessment Warwickshire County Council 12.3 Emergency Planning............................................................................................................90 12.4