Borough of Poole Unitary Authority Preliminary Flood Risk Assessment

APPENDIX 1 Borough of Poole Unitary Authority Preliminary Flood Risk Assessment Draft Final Report v3 June 2011 1. Executive Summary This report has been prepared to assist Borough of Poole in meeting their duties to manage local flood risk and deliver the requirements of the Flood Risk Regulations (2009). The Borough of Poole, as a unitary authority, is defined as a lead local flood authority (LLFA) within the regulations. This report represents the first stage of the requirements set out in the regulations. The Preliminary Flood Risk Assessment (PFRA) process is aimed at providing a high level overview of flood risk from local sources, primarily flooding from surface water, groundwater and ordinary watercourses. Flooding associated with the sea, main rivers and reservoirs is the responsibility of the Environment Agency and does not need to be considered as part of this report. The completed PFRA report must be submitted by Borough of Poole to the Environment Agency for review by 22 June 2011. The PFRA has been produced based on the Environment Agency‟s Final PFRA Guidance and Defra‟s Guidance on selecting Flood Risk Areas, both published in December 2010. Using the national methodology set by Defra, the Environment Agency identified indicative Flood Risk Areas across England. Of the ten areas identified, none of these fall within the Borough of Poole. This simply means that parts of the PFRA mandatory documentation is not applicable to Poole and therefore will not require completion. In order to gain a clearer understanding of the flood risk across the Borough of Poole, flood risk data and historic flood events were collected from local and national sources, the Environment Agency, water companies, emergency services and other risk management authorities. Quality and comprehensive records on flood extents and consequences were largely unavailable or considered of poor quality. No records of events that have occurred in Poole can be deemed to have significant harmful consequences as defined by the criteria set by the UK government Secretary of State and guidance provided by the Environment Agency. However, it may be noted that there is a risk of future flooding from local sources to areas across the Borough of Poole. Data from the Environment Agency has been used to calculate the number of properties that are at risk from flooding. 1 2. Contents 1. Executive Summary 2. Contents 3. Introduction 4. Lead Local Flood Authority responsibilities 5. Methodology and data review 6. Past flood risk 7. Future flood risk 8. Review of Indicative Flood Risk Areas 9. Identification of Flood Risk Areas 10. Next steps 11. Review and Approval Process 12. References 2 3. Introduction 3.1 Scope The Preliminary Flood Risk Assessment is an initial, high level, exercise aiming to review historical and potential, future flood risk and the determination of Flood Risk Areas. This report is to assess the local flood risk in Poole. Local flood risk includes flooding from surface water, groundwater, canals, lakes and small reservoirs. Flood risk from the sea, main rivers and large reservoirs is the responsibility of the Environment Agency and so is not considered in this report. This is unless it is considered that it may affect flooding from one of the sources above. The PFRA brings together existing and available information to determine the level of flood risk throughout the borough of Poole. Floods with significant harmful affects are only to be considered. 3.2 Aims and Objectives Under the Flood Risk Regulations (2009) Borough of Poole, as a Lead Local Flood Authority (LLFA), has a duty to prepare a Preliminary Flood Risk Assessment (PFRA). The assessment is an important step in understanding flooding within the borough of Poole. The work will also form a foundation for future studies, investment and action plans for flood risk management. The Flood Risk Regulations adopt a new institutional structure for the understanding and management of flood risk. The Preliminary Flood Risk Assessment involves an assessment of local flood risk, the preparation of a preliminary assessment report and the identification of any Flood Risk Areas, those areas at significant risk. The aim of the Flood Risk Regulations is to reduce the likelihood and consequences of flooding. The regulations came about in response to extreme flooding across Europe and came into force in England and Wales on 10 December 2009. Within the flood risk management cycle there are four stages: o the Preliminary Assessment Report o identification of Flood Risk Areas o Flood Hazard maps and Flood Risk Maps o Flood Risk Management Plans As there are no flood risk areas within the borough of Poole the subsequent stages are not required. These stages bring into domestic law the European Commission Floods Directive (Directive 2007/60/EC) on the assessment and management of flood risk across the European Union Member States. The aim of the PFRA is to provide an assessment of local flood risk across the borough, covering past flood events and the potential consequences of future floods. 3 3.3 The Study Area Poole lies in the south east of the South West River Basin District as shown in Fig 1.1. The borough of Poole has an administrative area of approximately 65Km2 with land stretching from sea level on the south coast to a height of 67m A.O.D, (Above Ordnance Datum). The borough of Poole supports a population of approximately 138,000 as of 2001. The area of Poole may have inflated values for population size to varying degrees throughout the year due to tourists. Bordering the north of Poole the river Stour flows from west to east and into Bournemouth. Some small streams flow from their source within the borough into this main river and other water sources flow from the land in a generally southerly direction to the sea. Most of the watercourses have been piped and many now are classified as surface water sewers. Previous studies have included the Borough of Poole Strategic Flood Risk Assessment (SFRAs). This is a planning tool. It is an assessment of all types of flood risk, including tidal, that is to inform the spatial planning process. It is a strategic level study on a local authority planning scale. The Environment Agency Catchment Flood Management Plans (CFMPs) identify areas at risk from flooding from main rivers. The SFRA has identified the areas at risk of flooding as Creekmoor, Hamworthy and Canford Magna, where 201-500 properties are at risk of flooding and also the larger area of Poole Town Centre where 501-1000 properties are at risk of future flooding, including tidal. Through other studies the potential effect of climate change and sea level rise have also been investigated within certain areas. Poole Town Centre area and Poole Harbour and the coast have been investigated to determine the extent of future flood extents based on the topography of the land and the potential sea level rise. The Borough of Poole has an adopted Core Strategy (February 2009) which is a development plan document with a policy therein, PCS 34 entitled Flood Risk. This Core Strategy steers flood risk in the Borough of Poole. Surface water (including groundwater) flooding was also considered within the SFRA with sustainable management of rainfall essential to reducing the future flood risk on development sites as well as on the surroundings. Tidal and coastal flood risk are set to increase with the drivers for flooding (surges, waves and relative sea level rise) affecting the probability of future developments in low-lying areas such as Poole town centre, as given in floodzone mapping. The main river catchment is the River Stour. The Stour lies to the north of the borough creating part of the boundary with East Dorset. On the South-West corner of the borough the Rock Lea River discharges into Lychett Bay following the landline curve of Turlin Moor and then out on into the Wareham Channel. 4 5 6 4. Lead Local Flood Authority Responsibilities 4.1 Introduction The preparation of a PFRA is just one of several responsibilities of the LLFAs under the new legislation. This section provides a brief overview of other responsibilities the Borough of Poole are obliged to fulfil under their role as a LLFA. 4.2 Co-ordination of Flood Risk Management In the review of the summer 2007 flooding, Sir Michael Pitt stated that „the role of local authorities should be enhanced so that they take on responsibility for leading the co-ordination of flood risk management in their areas‟. This recommendation was taken forward into the Flood Risk Regulations and the Flood and Water Management Act. As the designated LLFA, the Borough of Poole is therefore responsible for leading local flood risk management across the borough. Much of the local knowledge and technical expertise necessary for the Borough of Poole to fulfil their duties as a LLFA lies both within the borough and with other external partner organisations. The execution of the PFRA will promote collaborative working with external groups and organisations as they undertake their responsibilities to ensure effective and consistent management of local flood risk throughout the country and to contribute to the provision of a co-ordinated and holistic approach to flood risk management across the borough. Being a Lead Local Flood Authority, the Borough of Poole has a role to play in forging effective partnerships with the Environment Agency and Wessex Water, as well as other key stakeholders and other Risk Management Authorities. The statutory documents produced by the Council (PFRA, Flood Hazard Maps, Flood Risk Maps and the Surface Water Management Plan) will be considered by the Environment Overview and Scrutiny Committee and approved by Cabinet.

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