Level 1 Strategic Flood Risk Assessment Sedgemoor District Council Strategy and Development October 2015 [email protected] Level 1 Strategic Flood Risk Assessment Sedgemoor District Council 2015 Revision Schedule Rev Author Date Status and Descripton 02 AReading October Published version incorporating changes to document and mapping 2015 following consultation feedback. 01 AReading July 2015 DRAFT document for consultation with Risk Management Authorities and other stakeholders. Sedgemoor District Council 2015 Level 1 Strategic Flood Risk Assessment Contents 1 Introduction 1 2 The Sedgemoor District Council Study Area 5 3 Policy Context 8 4 Data Collection and Methodology 15 5 Broad-scale Assessment 26 6 Focused Assessments 28 7 Developer Guidance 38 8 Development Site Drainage 40 9 Emergency Planning 47 10 Summary & Recommendations 48 Appendix 1 - Mapping 52 Appendix 2 - Wessex Water Sewer Flooding Data 53 Appendix 3 - Emergency Planning Mapping 54 Level 1 Strategic Flood Risk Assessment Sedgemoor District Council 2015 1 Introduction 1 Background 1.1 In 2008 Sedgemoor District Council completed a level 1 Strategic Flood Risk Assessment (SFRA) as part of the evidence base for the Council’s Core Strategy (1). The Core Strategy was later adopted in 2011 and is the current Development Plan for the District. The National Planning Policy Framework (NPPF) states that Local Plans should be supported by an SFRA which should be prepared in consultation with the Environment Agency and other Risk Management Authorities (2). This document therefore updates the previous level 1 SFRA document to provide appropriate information to inform the Council’s Core Strategy (Local Plan) review process (2011-2032). The updated SFRA will form a critical part of the Council’s evidence base in terms of informing the Sustainability Appraisal, identifying appropriate locations for development (by applying the Sequential Test), and preparing the Local Plan’s placemaking and district wide flood risk policies. It will also underpin wider decision making within the District, including assisting the Development Management process. When published it will be an important reference document for applicants preparing Sequential/Exception Test evidence and site specific Flood Risk Assessments to support planning application submissions. 1.2 Given the scale of flood risk in the District it is expected that further level 2 SFRA work may also be required. Level 2 SFRA work is necessary if, taking into account wider sustainability objectives, it is not possible to direct all development outside of medium or high risk areas. The Council intend to scope the need for further SFRA level 2 evidence later in 2015 after the initial Local Plan review consultation. Until this time, for planning application purposes, the current level 2 SFRA available from the Council's website should still be considered as the most up-to-date information on tidal breach and overtopping risk for the Bridgwater and Burnham-on-Sea/Highbridge areas (3). The Need for an Updated Level 1 SFRA 1.3 Since previous SFRA work there have been a number of significant changes to both flood risk management and planning policy, which means that a comprehensive update to the level 1 SFRA is necessary. These changes include: 1. A number of significant flood events that have occurred in the District since the previous SFRA that need to be taken into account in the updated data. This includes the recent winter 2013-14 flooding on the Somerset Levels. The significant damage and disruption caused by this flood event resulted in Risk Management Authorities coming together to publish of the 20 year Somerset Levels and Moors Flood Action Plan. 2. Changes in the planning system since the publication of the previous SFRA, including the Localism Act (2011) and the NPPF, which replaces Planning Policy Statement 25 (PPS25). The PPS25 companion Practice Guide has also been replaced by the Planning Practice Guidance, published March 2014. While the new planning policy framework retains many of the previous flood risk policy aims of PPS25, an update is required to ensure continued compliance with national planning policy. 3. Many of the provisions of the Flood and Water Management Act 2010 and EU Flood Directive have been implemented, which have significant implications on roles and responsibilities of different organisations in relation to flood risk management. 1 Scott Wilson, 'Sedgemoor District Council Strategic Flood Risk Assessment Level 1 Report', 2008. 2 DCLG, 'National Planning Policy Framework', 2012, p. 24. 3 Scott Wilson, 'Sedgemoor District Council Level 2 Strategic Flood Risk Assessment', 2009. 2 Sedgemoor District Council 2015 Level 1 Strategic Flood Risk Assessment 1 Introduction 4. New and updated mapping in relation to sources of flooding is available, an example being the ‘Updated Flood Map for Surface Water’. It is therefore important to ensure the flood risk evidence base for the Local Plan review is based on the most up to date information. 5. With changes to organisations roles and responsibilities new and updated flood risk policy documents are now available, including for example updated Catchment Flood Management Plans, Local Flood Risk Management Strategies and the County’s Preliminary Flood Risk Assessment. Aim and Objectives 1.4 The intention is to prepare the document under the requirements of the NPPF and the Flood Risk and Coastal Change section of the accompanying Planning Practice Guidance (4). Following publication of the NPPF the Environment Agency has also published SFRA Guidance detailing key outputs for SFRA’s (5). The aim of an SFRA in general is to provide an assessment of the risk to the District from all sources of flooding (including climate change implications), and to assess the impact that land use changes and new development in the area will have on flood risk. The aim of this level 1 study is to provide comprehensive information to inform policies in the Local Plan relating to flood risk management. It needs to provide a sufficiently detailed assessment so as to allow the Local Planning Authority to apply the Sequential Test to the location of new development, and determine whether development can be allocated outside of high and medium flood risk areas, taking account of all sources of flooding. To achieve this aim the objectives of this level 1 study are: To produce updated maps for the Sedgemoor area showing Main Rivers, ordinary watercourses and Flood Zones, including defining Flood Zone 3b (functional floodplain) for planning purposes; To provide an assessment of the implications of climate change on flood risk over an appropriate time period; Provide information and mapping in relation to other sources of flooding, for example surface water, reservoir and groundwater risk; Provide details of flood risk management measures, including the location and standard of flood defences, flood warning coverage and emergency plans; Using the above information on all sources of flooding, undertake a focused assessment of the main settlements to determine the potential to sequentially locate any new development to areas at low risk, or where further level 2 work may be required to accommodate strategic development requirements; Provide recommendations regarding use of the SFRA for planning policy, including the identification of planning policies that will successfully minimise and manage flood risks; and Provide any locally specific guidance regarding the preparation of Flood Risk Assessments for new development, including the suitability of different sustainable drainage techniques. 4 DCLG, 'Planning Practice Guidance', 2015. http://planningguidance.planningportal.gov.uk/blog/guidance/flood-risk-and-coastal-change (Accessed 06/05/2015). 5 Environment Agency, 'Strategic Flood Risk Assessments - Guidance to support the National Planning Policy Framework', 2013. Level 1 Strategic Flood Risk Assessment Sedgemoor District Council 2015 3 Introduction 1 Consultation and Cooperation 1.5 Consultation and co-operation with key stakeholders is critical to establishing the evidence base for the new Local Plan, particularly in light of the ‘Duty to Cooperate’ brought in by the Localism Act 2011 (Section 110). This is of key importance for flood risk evidence given different organisations responsibilities, and the fact that river catchments and sources of flood risk do not respect administrative boundaries. 1.6 The Planning Practice Guidance lists the key Risk Management Authorities that need to be involved in the preparation of the SFRA. A description of these organisations, along with other local stakeholders specific to the Sedgemoor area, is detailed in the section 2 of this report. Following the Winter 2013/14 floods a key action from the Flood Action Plan was to improve cooperation between Flood Risk Management Authorities with the establishment of the Somerset Rivers Authority. The Somerset Rivers Authority was launched in January 2015 and will play a key role in bringing together and co-ordinating the Environment Agency, Internal Drainage Boards, Lead Local Flood and Highway Authority and other Somerset authorities, for continued deliver of the Flood Action Plan. The Somerset River Authority should ensure delivery of flood risk management in the County benefits from the collective experience and knowledge of all of its members. Format and Structure of the Document 1.7 This rest of this SFRA report is split into the following sections: Section 2:The Sedgemoor District Council Study