LONDON BOROUGH OF BARKING AND DAGENHAM STRATEGIC FLOOD RISK ASSESSMENT LEVEL 1 August 2017 One borough; one community; London’s growth opportunity LONDON BOROUGH OF BARKING AND DAGENHAM STRATEGIC FLOOD RISK ASSESSMENT (SFRA) LEVEL 1 London Borough of Barking and Dagenham Job Number 3514006A Prepared for London Borough of Barking and Dagenham Town Hall 1 Town Square Barking IG117LU Prepared by WSP | Parsons Brinckerhoff Kings Orchard 1 Queen Street Bristol BS2 0HQ 0117 933 6200 Report Title : London Borough of Barking and Dagenham Strategic Flood Risk Assessment (SFRA) Level 1 Report Status : Final Job No : 3514006A Date : August 2017 DOCUMENT HISTORY AND STATUS Document control Checked by Prepared by David Fahey / Simon Olivier Andrew Lee (technical) Checked by Approved by Jonathan Ralph Joanna Goodwin (quality assurance) Revision details Pages Version Date Comments affected First issue – draft issued for review by the London Borough of 1.0 June 2015 - Barking and Dagenham and Environment Agency 2.0 July 2015 - General updates throughout report following Council review. General updates throughout report following Environment 3.0 June 2016 - Agency review. Issued as final. August Minor updates throughout report following final review by 4.0 - 2016 LBBD. Issued as final. General updates throughout report following Environment February 5.0 - Agency review and updated climate change mapping for the 2017 Mayes Brook and Beam River. Issued as final. March 6.0 - Modelling of lower extents of Mayes Brook completed 2017 7.0 June 2017 - Local plan period amended. Issued as final August Minor updates throughout report following final review by 8.0 - 2017 Environment Agency. Issued as final. London Borough of Barking and Dagenham Strategic Flood Risk Assessment (SFRA) Level 1 CONTENTS Page Glossary Executive Summary INTRODUCTION 1 1 INTRODUCTION 3 1.1 Overview 3 1.2 Local Context 4 1.3 Future Development in Barking and Dagenham 6 SFRA APPROACH 9 2 SFRA APPROACH 11 2.1 The Need for the SFRA 11 2.2 Approach to Completing the SFRA 11 2.3 Proposed Use of the SFRA 11 POLICY FRAMEWORK 13 3 POLICY FRAMEWORK 15 3.1 Introduction 15 3.2 National Planning Policy and Strategy 15 3.3 Regional Planning Policy and Strategy 19 3.4 Local Planning Policy 25 DATA COLLECTION 29 4 DATA COLLECTION 31 4.1 Overview 31 4.2 Consultation 31 4.3 Environment Agency Flood Maps 32 4.4 Surface Water Management Plan 34 4.5 Historical Flooding 35 4.6 Detailed Hydraulic Modelling 35 4.7 Flood Defences 36 4.8 Topography and Geology 38 DATA INTERPRETATION 39 5 DATA INTERPRETATION 41 5.1 Introduction 41 5.2 Delineation of the NPPF Flood Zones (Fluvial and Tidal Flooding) 41 5.3 Localised Flooding Issues 42 5.4 Assessment of Flood Risk (Flood Hazard) 45 5.5 Potential Impacts of Climate Change on Flood Risk 49 5.6 Topography and Geology 54 Strategic Flood Risk Assessment (SFRA) Level 1_V8.0_Final Prepared by WSP Parsons Brinckerhoff August 2017 for London Borough of Barking & Dagenham - iii - London Borough of Barking and Dagenham Strategic Flood Risk Assessment (SFRA) Level 1 FLOOD RISK IN THE LONDON BOROUGH OF BARKING and DAGENHAM 55 6 FLOOD RISK IN THE LONDON BOROUGH OF BARKING and DAGENHAM 57 6.1 Introduction 57 6.2 The Rivers in the Borough of Barking and Dagenham 57 6.3 Historical Flooding 63 6.4 Spatial Variations of Flood Risk in the Character Areas 66 6.5 Impacts of Climate Change on Flood Risk 72 6.6 Residual Risk of Flooding 73 6.7 The Source – Pathway Receptor Model 74 SUSTAINABLE MANAGEMENT OF FLOOD RISK 77 7 SUSTAINABLE MANAGEMENT OF FLOOD RISK 79 7.1 Overview 79 7.2 Responsibility for Flood Risk Management 79 7.3 Planning and Development Control 82 7.4 SFRA Interpretation 91 7.5 Detailed Flood Risk Assessment 92 7.6 Resistance and Resilience Measures 100 7.7 Sustainable Drainage Systems (SUDS) 103 7.8 Local Community Actions to Reduce Flood Damage 110 7.9 Emergency Planning 111 7.10 Insurance 114 CONCLUSIONS AND RECOMMENDATIONS 117 8 CONCLUSION AND RECOMMENDATIONS 119 8.1 Overview of SFRA Outcomes 119 8.2 Development Control Guidance 119 8.3 Updating the SFRA 121 APPENDIX A: MAP OF THE LONDON BOROUGH OF BARKING & DAGENHAM APPENDIX B: MAP OF THE MAIN RIVERS IN BARKING & DAGENHAM APPENDIX C: DEFENCES, STRUCTURES AND FLOOD STORAGE AREAS APPENDIX D: FLOOD ZONES IN BARKING & DAGENHAM APPENDIX E: AREAS BENEFITING FROM DEFENCES APPENDIX F: SURFACE WATER FLOOD EXTENTS APPENDIX G: FLOOD HAZARD AND RATE OF INUNDATION MAPS APPENDIX H: THAMES WATER DG5 FLOODING INFORMATION APPENDIX I: EXTRACTS FROM THE BARKING AND DAGENHAM SWMP APPENDIX J: HISTORIC FLOOD EVENTS APPENDIX K: TOPOGRAPHIC MAP OF BARKING & DAGENHAM APPENDIX L: BARKING & DAGENHAM WARDS APPENDIX M: CHARACTER AREAS AND FLOOD RISKS Strategic Flood Risk Assessment (SFRA) Level 1_V8.0_Final Prepared by WSP Parsons Brinckerhoff August 2017 for London Borough of Barking & Dagenham - iv - London Borough of Barking and Dagenham Strategic Flood Risk Assessment (SFRA) Level 1 APPENDIX N: FLOOD WARNING AND ALERT AREAS (FLUVIAL & TIDAL) APPENDIX O: EXISTING VULNERABLE LAND USES AND EMERGENCY SERVICES Strategic Flood Risk Assessment (SFRA) Level 1_V8.0_Final Prepared by WSP Parsons Brinckerhoff August 2017 for London Borough of Barking & Dagenham - v - London Borough of Barking and Dagenham Strategic Flood Risk Assessment (SFRA) Level 1 GLOSSARY Catchment Flood Management Plans. A CFMP is a high level strategic planning tool CFMP which explores and defines long-term sustainable policies for flood risk management. The Core Strategy is the primary document in the Barking and Dagenham Local Plan Core Strategy and sets out the Councils long-term vision, spatial strategy and core policies for shaping the future development of Barking and Dagenham up to 2025. A discrete geographical area (usually a hydrological catchment) where multiple and Critical interlinked sources of flood risk (surface water, groundwater, sewer, main river and/or Drainage Area tidal) cause flooding during severe weather thereby affecting people, property or local (CDA) infrastructure. Department for Communities and Local Government DCLG De facto Flood A structure that provides a flood defence function, however has not been built and/or Defence maintained for this purpose (e.g. boundary wall). Defra (Department for Environment, Food and Rural Affairs) is a UK Government Department. The overarching challenge for Defra is to enable everyone to live within Defra our environmental means by tackling climate change internationally and through domestic action to reduce greenhouse gas emissions, and to secure a healthy, resilient, productive and diverse natural environment. The carrying out of building, engineering, mining or other operations, in, on, over or Development under land, or the making of any material change in the use of a building or other land. Development DPD’s are a series of documents that form the Local Plan for Barking and Dagenham. Plan They set out the planning policies of the Borough and are subject to independent Document examination. (DPD) A water-company held register of properties which have experienced sewer flooding DG5 Register due to hydraulic overload, or properties which are ‘at risk’ of sewer flooding more frequently than once in 20 years. Forum founded in 2007 to assess flood risks associated predominantly with surface Drain London water flooding across all London Boroughs. Digital Terrain Modelling. DTMs are topographic models of the bare earth that can be manipulated by computer programs. DTM files contain elevation data of terrain in a DTM digital format that relates to a rectangular grid. Vegetation, buildings and other cultural features are removed digitally - leaving just the underlying terrain. Flood and Part of the UK Government response to Sir Michael Pitt’s report on the Summer 2007 Water floods, the aim of which is to clarify the legislative framework and responsibilities for Management managing flood risk in England. Act 2010 Flood Risk Transposition of the EU Floods Directive into UK law. The EU Floods Directive is a Regulations piece of European Community (EC) legislation to specifically address flood risk by 2009 prescribing a common framework for its measurement and management. Defines flood zones based on annual probability of flooding from fluvial and tidal Flood Map for sources to inform development planning and flood risk assessment. Nationally Planning consistent delineation of ‘high’, ‘medium’ and ‘low’ flood risk updated by the Rivers and Environment Agency as deemed appropriate, typically on a quarterly basis. Strategic Flood Risk Assessment (SFRA) Level 1_V8.0_Final Prepared by WSP Parsons Brinckerhoff August 2017 for London Borough of Barking & Dagenham - vii - London Borough of Barking and Dagenham Strategic Flood Risk Assessment (SFRA) Level 1 Sea) Flood Zone Map Flood Zone 1 This zone comprises land assessed as having less than a 1 in 1000 (0.1%) annual Low probability of flooding from rivers or the sea in any year. Probability Flood Zone 2 This zone comprises land assessed as having between a 1 in 100 (1%) and 1 in 1000 Medium (0.1%) annual probability of flooding from rivers, or between a 1 in 200 (0.5%) and 1 Probability in 1000 (0.1%) annual probability of flooding from the sea in any year. Flood Zone 3a This zone comprises land assessed as having a 1 in 100 (1%) or greater annual High probability of flooding from rivers or a 1 in 200 (0.5%) or greater annual probability of Probability flooding from the sea in any year. This zone comprises land where water has to flow or be stored in times of flood. Flood Zone 3b SFRAs should identify this flood zone as land that would typically flood with an annual Functional probability of 1 in 20 (5%) or greater in any year, or is designed to flood in an extreme Floodplain (0.1%) flood, or at another probability to be agreed between the local planning authority and the Environment Agency, including water conveyance routes.