West Somerset Catchment Flood Management Plan Summary Report June 2012 Managing Flood Risk We Are the Environment Agency
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West Somerset Catchment Flood Management Plan Summary Report June 2012 managing flood risk We are the Environment Agency. It’s our job to look after your environment and make it a better place – for you, and for future generations. Your environment is the air you breathe, the water you drink and the ground you walk on. Working with business, Government and society as a whole, we are making your environment cleaner and healthier. The Environment Agency. Out there, making your environment a better place. Published by: Environment Agency Manley House Kestrel Way Exeter EX2 7LQ Tel: 0870 8506506 Email: [email protected] www.environment-agency.gov.uk © Environment Agency All rights reserved. This document may be reproduced with prior permission of the Environment Agency. June 2012 Introduction I am pleased to introduce our summary of the West Somerset Catchment Flood Management Plan (CFMP). This CFMP gives an overview of the flood risk in the West Somerset catchment and sets out our preferred plan for sustainable flood risk management over the next 50 to 100 years. The West Somerset CFMP is one of 77 CFMPs for The West Somerset catchment has a history of flood England and Wales. Through the CFMPs, we have risk. Over the last 50 years engineering schemes have assessed inland flood risk across all of England and been implemented to reduce flood risk in the Wales for the first time. The CFMP considers all types of catchment. At present 1,600 properties are at risk in inland flooding, from rivers, ground water, surface the catchment in a 1% event (taking into account flood water and tidal flooding, but not flooding directly from defences). This will increase to over 2,040 properties in the sea (coastal flooding), which is covered by the future. Shoreline Management Plans (SMPs). Our coverage of We cannot reduce flood risk on our own, we will surface and ground water is however limited due to a therefore work closely with all our partners to improve lack of available information. the co-ordination of flood risk activities and agree the The role of CFMPs is to establish flood risk management most effective way to manage flood risk in the future. policies which will deliver sustainable flood risk We have worked with others including: Somerset management for the long term. This is essential if we County Council, Natural England, Wessex Water and the are to make the right investment decisions for the National Farmers Union to develop this plan. future and to help prepare ourselves effectively for the This is a summary of the main CFMP document, if you impact of climate change. We will use CFMPs to help us need to see the full document an electronic version can target our limited resources where the risks are be obtained by emailing greatest. [email protected] This CFMP identifies flood risk management policies to or alternatively paper copies can be viewed at any of assist all key decision makers in the catchment. It was our offices in South West Region. produced through a wide consultation and appraisal process, however it is only the first step towards an integrated approach to Flood Risk Management. As we all work together to achieve our objectives, we must monitor and listen to each others progress, discuss what has been achieved and consider where we may Richard Cresswell need to review parts of the CFMP. South West Regional Director Environment Agency West Somerset Catchment Flood Management Plan 1 Contents The purpose of a CFMP in managing flood risk 3 Catchment overview 4 Current and future flood risk 6 Future direction for flood risk management 10 Sub-areas 1 Lower River Aller sub-area 12 2 Exmoor Plateau sub-area 13 3 Middle Catchments sub-area 14 4 Lower River Avill sub-area 16 5 Minehead sub-area 17 6 Watchet sub-area 18 7 Williton sub-area 19 8 Hills and Cliffs sub-area 20 Map of CFMP policies 21 2 Environment Agency West Somerset Catchment Flood Management Plan The purpose of a CFMP in managing flood risk CFMPs help us to understand the • Internal Drainage Boards (IDB), CFMPs aim to promote more scale and extent of flooding now and water companies and other sustainable approaches to in the future, and set policies for utilities to help plan their managing flood risk. The policies managing flood risk within the activities in the wider context of identified in the CFMP will be catchment. CFMPs should be used to the catchment; delivered through a combination of inform planning and decision different approaches. Together with • transportation planners; making by key stakeholders such as: our partners, we will implement • land owners, farmers and land these approaches through a range • the Environment Agency, who will managers that manage and of delivery plans, projects and use the plan to guide decisions operate land for agriculture, actions. on investment in further plans, conservation and amenity projects or actions; The relationship between the CFMP, purposes; delivery plans, strategies, projects • Regional Assemblies and local • the public and businesses to and actions is shown in Figure 1. authorities who can use the plan enhance their understanding of to inform spatial planning flood risk and how it will be activities and emergency managed. planning; Figure 1. The relationship between CFMPs, delivery plans, projects and actions Policy planning • CFMPs and Shoreline Management Plans. • Action plans define requirement for delivery plans, projects and actions. Policy delivery plans (see note) Projects and actions • Influence spatial planning to reduce risk and • Make sure our spending delivers the best restore floodplains. possible outcomes. • Prepare for and manage floods (including local • Focus on risk based targets, for example numbers Flood Warning plans). of households at risk. • Managing assets. • Water level management plans. • Land management and habitat creation. Note: Some plans may not be led by us – we may identify the • Surface water management plans. need and encourage their development. Environment Agency West Somerset Catchment Flood Management Plan 3 Catchment overview The catchment of the rivers in the The overall catchment area is about The catchment contains a number of West Somerset CFMP are located in 320 square kilometres and has a designated sites of national and the south west of England. population of around 31,000. It’s a international importance. These rural catchment, with urban areas include Exmoor National Park, which The rivers drain from Exmoor and the making up only four per cent of the is also an Environmentally Sensitive Quantocks, flowing north to the total. Its main urban areas, generally Area and a Special Area of Bristol Channel. Map 1 shows the located on the coastal plain, include Conservation (SAC); the Quantocks location and extent of the West Minehead, Watchet and Williton. which is an Area of Outstanding Somerset CFMP area. It includes the Natural Beauty that includes the River Avill, Pill River, Washford River, The rivers and streams flow from Quantocks Oakwood’s SAC; Horner Monksilver Stream, Doniford Stream, their sources on Exmoor and the Wood National Nature Reserve, 12 Hawkcombe Stream, Horner Water Quantock Hills, in the south and east Sites of Special Scientific Interest and River Aller. The downstream of the catchment respectively. They (SSSI); nine National Nature limits of the CFMP area meets with are steep in nature and flow towards Reserves and 135 Scheduled the upstream boundary of the North the Bristol Channel in the north. Monuments. Devon and Somerset Shoreline Geology has a significant influence Management Plan (SMP) boundary at on the response to rainfall. The the Bristol Channel coast. geology of West Somerset has low The North Devon and Somerset, and permeability, this contributes to the Severn Estuary Shoreline high level of overland flow and the Management Plans deal with coastal rapid response of the rivers to flood management, while the CFMP rainfall. considers the risk from tidal flooding. 4 Environment Agency West Somerset Catchment Flood Management Plan Map 1. Location and extent of the West Somerset CFMP area Legend West Somerset CFMP Urban areas Main rivers Railway Motorway Minehead Porlock Watchet Williton N Taunton 0 3 6 9 12 Kilometres © Crown Copyright. Environment Agency 100026380. ➜ Flooding from the River Avill at Dunster in November 1963 Environment Agency West Somerset Catchment Flood Management Plan 5 Current and future flood risk Overview of the current flood risk What is at risk? Flood risk has two components: the Currently the main sources of flood At present there are around 2,700 chance (probability) of a particular risk for people, property, people and 1,600 commercial and flood and the impact (or infrastructure and the land are: residential properties at risk in the consequence) that the flood would whole catchment from a 1% annual • river flooding from the River Aller have if it happened. The probability probability river flood taking into in Allerford and Bossington, of a flood relates to the likelihood of account current flood defences. Washford River in Washford, a flood of that size occurring within a Monksilver Stream in Williton and This means that 8.5% of the total one year period. It is expressed as a Doniford Stream in Doniford; population living in the catchment percentage. For example, a 1% flood are currently at risk from flooding. has a 1% chance or 0.01 probability • tidal flooding in Minehead, of occurring in any one year, and a Porlock and Blue Anchor; It is difficult to assess the current 0.5% flood has a 0.5% chance or impact of flooding to environmental • surface water drainage flooding, 0.005 probability of occurring in any features. Many designated sites at which has occurred in Minehead, one year.