King's Lynn and West Norfolk Settlements Surface Water Management Plan
Total Page:16
File Type:pdf, Size:1020Kb
King's Lynn and West Norfolk Settlements Surface Water Management Plan Stage 1 Report November 2010 Norfolk County Council Client Task Group King's271567DA02 Lynn BNI andEVT West01 A King's Lynn and West Norfolk Settlements SWMP Stage 1 Report - Working Draft Norfolk Settlements19 November 2010 Surface Water Management Plan Stage 1 Report November 2010 Norfolk County Council Client Task Group 7th Floor, County Hall, Martineau Lane, Norwich Mott MacDonald, Demeter House, Station Road, Cambridge CB1 2RS, United Kingdom T +44(0) 1223 463500 F +44(0) 1223 461007 W www.mottmac.com King's Lynn and West Norfolk Settlements Surface Water Management Plan Issue and revision record Revision Date Originator Checker Approver Description 01 19/11/10 Jonathan Chinnock Richard Gamble Mark Frith Final This document is issued for the party which commissioned it We accept no responsibility for the consequences of this and for specific purposes connected with the above-captioned document being relied upon by any other party, or being used project only. It should not be relied upon by any other party or for any other purpose, or containing any error or omission which used for any other purpose. is due to an error or omission in data supplied to us by other parties This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it. Mott MacDonald, Demeter House, Station Road, Cambridge CB1 2RS, United Kingdom T +44(0) 1223 463500 F +44(0) 1223 461007 W www.mottmac.com King's Lynn and West Norfolk Settlements Surface Water Management Plan Content Chapter Title Page Executive Summary 1 1. Introduction 3 1.1 Background________________________________________________________________________ 3 1.2 Overview of the SWMP Process________________________________________________________ 5 2. Partnership Establishment 12 2.1 Partner Organisations_______________________________________________________________ 12 2.2 Roles and Responsibilities ___________________________________________________________ 12 2.3 Treatment of Sensitive Information from Partner Organisations _______________________________ 15 2.4 Engagement Plan __________________________________________________________________ 16 2.5 Objectives of the King’s Lynn and West Norfolk Settlements SWMP ___________________________ 20 3. Data Collation 21 3.1 Study Area _______________________________________________________________________ 21 3.2 Historic Pluvial or Capacity Surface Water Flooding________________________________________ 26 3.3 Historic Sewer Flooding _____________________________________________________________ 28 3.4 Underground Surface Water Drainage Assets ____________________________________________ 29 3.5 Sewer System Assets _______________________________________________________________ 29 3.6 Potential Development within the King’s Lynn and West Norfolk Settlements SWMP Area __________ 30 3.7 Usability of the Data ________________________________________________________________ 31 3.8 Gap Analysis______________________________________________________________________ 31 3.9 Mapping and Spatial Analysis_________________________________________________________ 32 3.10 Identified Areas Vulnerable to Surface Water Flooding _____________________________________ 32 4. Suggested Approach for Phases 2 and 3 33 4.1 Risk Assessment (Phase 2) and Options Appraisal (Phase 3) ________________________________ 33 4.2 Suggested Modelling Approach for Detailed Assessment ___________________________________ 34 Appendices 36 Appendix A. Maps ____________________________________________________________________________ 37 Appendix B. Incoming Documents Register ________________________________________________________ 53 Appendix C. Meeting Minutes ___________________________________________________________________ 56 C.1. Meeting Minutes of the King’s Lynn and West Norfolk Settlements SWMP Inception Meeting 27.07.10 _________________________________________________________________________ 57 C.2. Meeting Minutes of the King’s Lynn and West Norfolk Settlements SWMP Progress Meeting 1 08.10.10 _________________________________________________________________________ 60 C.3. Meeting Minutes of the King’s Lynn and West Norfolk Settlements SWMP Progress Meeting 2 08.11.10 _________________________________________________________________________ 64 Appendix D. Recorded Historical Flood Incidents ____________________________________________________ 69 D.1. Historical Surface Water Recorded Incidents from the Environment Agency _____________________ 70 D.2. Historical Recorded Flood Events from Norfolk Fire and Rescue Service _______________________ 71 Appendix E. King’s Lynn and West Norfolk Settlements SWMP Contact List _______________________________ 72 Appendix F. Highway Surface Drainage Lifecycle Management Plan ____________________________________ 73 271567DA02/BNI/EVT/01/A 19 November 2010 King's Lynn and West Norfolk Settlements SWMP Stage 1 Report King's Lynn and West Norfolk Settlements Surface Water Management Plan Glossary 87 Maps Map A.1: King’s Lynn and West Norfolk Settlements SWMP Study Areas_______________________________ 38 Map A.2: Watercourses in the King’s Lynn and West Norfolk Settlements SWMP Study Areas ______________ 39 Map A.3: Environment Agency Indicative Flood Zones _____________________________________________ 40 Map A.4: Highway Drainage Information from Norfolk County Council _________________________________ 41 Map A.5: Internal Drainage Board Boundaries____________________________________________________ 42 Map A.6: Topographic LiDAR Data for the King’s Lynn and West Norfolk Settlements SWMP Study Areas at a 1m Resolution________________________________________________________________________ 43 Map A.7: Topographic LiDAR Data for the King’s Lynn and West Norfolk Settlements SWMP Study Areas at a 2m Resolution________________________________________________________________________ 44 Map A.8: Anecdotal Information Regarding Historic Flood Events affecting Individuals or Businesses _________ 45 Map A.9: Areas Vulnerable to Surface Water Flooding _____________________________________________ 46 Map A.10: Pollution Incidents from the Environment Agency__________________________________________ 47 Map A.11: Sewer Network within the King’s Lynn and West Norfolk Settlements SWMP Study Areas __________ 48 Map A.12: Proposed Development Locations within the King’s Lynn and West Norfolk Settlements SWMP Study Areas ___________________________________________________________________________ 49 Map A.13: Source Protection Zones within the King’s Lynn and West Norfolk Settlements SWMP Study Areas __ 50 Map A.14: Bedrock Geology within the King’s Lynn and West Norfolk Settlements SWMP Study Areas ________ 51 Map A.15: Superficial Geology within the King’s Lynn and West Norfolk Settlements SWMP Study Areas_______ 52 Figures Figure 1.1: Phases of a SWMP according to the DEFRA Technical Guidance, March 2010.___________________ 7 Tables Table 1.1: Levels of assessment in a SWMP study __________________________________________________ 8 Table 1.2: Key elements identified for the King’s Lynn and West Norfolk Settlements SWMP ________________ 10 Table 2.1: Roles and Responsibilities of the King’s Lynn and West Norfolk Settlements SWMP Partnership_____ 12 Table 2.2: Roles and Responsibilities of the King’s Lynn and West Norfolk Key Stakeholders ________________ 14 Table 2.3: Engagement Plan Summary __________________________________________________________ 17 Table 3.1: Settlement Groupings _______________________________________________________________ 21 Table 3.2: Principal Watercourses ______________________________________________________________ 22 Table 3.3: Bedrock and Superficial Geology ______________________________________________________ 23 Table 3.4: Current and future fluvial and tidal flood risk for King’s Lynn town _____________________________ 24 Table 3.5: Internal Drainage Boards within the SWMP study areas ____________________________________ 26 Table 3.6: Significant reported flood events between 2001 – 2009 from recorded incidents by Norfolk Fire and Rescue Service____________________________________________________________________ 27 Table 3.7: Recorded flooding events in Norfolk from the Norfolk Resilience Forum Community Risk Register____ 27 Table 3.8: Potential strategic location of housing in the King’s Lynn and West Norfolk area__________________ 31 Table 4.1: Detailed elements of the Risk Assessment and Options Appraisal_____________________________ 34 271567DA02/BNI/EVT/01/A 19 November 2010 King's Lynn and West Norfolk Settlements SWMP Stage 1 Report King's Lynn and West Norfolk Settlements Surface Water Management Plan 271567DA02/BNI/EVT/01/A 19 November 2010 King's Lynn and West Norfolk Settlements SWMP Stage 1 Report King's Lynn and West Norfolk Settlements Surface Water Management Plan Executive Summary This report concerns Stage 1 of the King’s Lynn and West Norfolk Settlements Surface Water Management Plan (SWMP). The aim of a SWMP is to understand and resolve complex and high risk surface water flooding problems in urbanised areas. A SWMP brings together key local partners, with responsibility for surface water and drainage in their areas, to collaborate to investigate the causes of surface water flooding and agree the most cost effective way of managing surface water flood risk. The principal output from a SWMP study is an action