LIT 10224

Flood risk management plan

South West river basin district summary March 2016

What are flood risk management plans? Flood risk management plans (FRMPs) explain the risk of flooding from rivers, the sea, surface water, groundwater and reservoirs. FRMPs set out how risk management authorities will work with communities to manage flood and coastal risk over the next 6 years. Risk management authorities include the Environment Agency, local councils, internal drainage boards, Highways Authorities, Highways England and lead local flood authorities (LLFAs). Each EU member country must produce FRMPs as set out in the EU Floods Directive 2007. Each FRMP covers a specific river basin district. There are 11 river basin districts in England and Wales, as defined in the legislation. A river basin district is an area of land covering one or more river catchments. A river catchment is the area of land from which rainfall drains to a specific river. Each river basin district also has a river basin management plan, which looks at how to protect and improve water quality, and use water in a sustainable way. FRMPs and river basin management plans work to a 6- year planning cycle. The current cycle is from 2015 to 2021. We have developed the South West FRMP alongside the South West river basin management plan so that flood defence schemes can provide wider environmental benefits.

Both flood risk management and river basin planning form an important part of a collaborative and integrated approach to catchment planning for water. Building on this essential work, and in the context of the Governments 25-year environment plan, we aim to move towards more integrated planning for the environment over the next cycle. This will be done on a catchment basis and will draw together and integrate objectives for flood risk management, water management, and biodiversity, with the aim of maximising the multiple benefits that can be achieved.

Flood risk in the South West river basin district The South West river basin district covers 21,000km2 and includes Cornwall, the Isles of Scilly, Devon, Dorset, Somerset, and parts of North Somerset, Hampshire and Wiltshire. It is divided into 9 management catchments and includes 1 strategic area, the Somerset Levels and Moors, as shown in Figure 1. Strategic areas consider flood risk management across more than one river catchment, so that organisations can work together in a co-ordinated way. River catchments in the South West river basin district vary considerably, leading to lots of different types of flood risk. Somerset has predominantly flat catchments with wide rivers that take a long time to respond to rainfall. Devon, Cornwall and West Dorset have smaller, steep catchments with fast-flowing rivers that respond rapidly to rainfall. Rivers in the Avon Hampshire management catchment receive large flows from chalk aquifers (where water is stored underground). These rivers react relatively slowly to rainfall but long periods of wet weather can result in prolonged flooding. The long thin maritime nature of the river basin, with two exposed Atlantic coastlines of almost 1,000km in length mean that it’s very vulnerable to storms, coastal flooding and river tide locking (when the level of the incoming high tide stops the river water flowing out to sea). These flood risks have been clearly demonstrated over the last few years. High energy waves and storms from the Atlantic can cause extensive physical damage to defences and property, including the Isles of Scilly.

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In the South West river basin district there are over 36,000 people living at high risk of flooding from rivers and the sea. Over 25,000 people are at high risk of surface water flooding (flooding which happens when drainage systems become overloaded with high volumes of rainfall). Towns such as Plymouth, Exeter, Taunton, Bridgwater and Poole have large numbers of properties at risk from multiple sources of flooding. In these areas, risk management authorities will work together to manage the risks of flooding from rivers, the sea, surface water and sewers. Being largely rural, many people live outside major towns and cities. Delivering protection to these remote communities provides challenges but improving community resilience and flood warning is a very important part of the solution. In parts of Devon, Cornwall and Dorset where there are steep valleys, river levels can rise very quickly during intense rainfall. These are known as ‘rapid response areas’. This poses a big risk, particularly to these small or dispersed communities. The agricultural nature has a major influence on the water environment. Learning from those who manage the land provides opportunities to work in partnership to deliver benefits to key communities. In some lowland areas, such as the Somerset Levels and Moors, land is at or near sea level and lies on manmade drainage systems, including channels, pumping stations and land drainage. Flooding in these areas can be significant and can last for months at a time. The South West river basin district has a limited network of major roads and there is a single railway line in and out of Devon and Cornwall. Flooding can significantly affect main transport networks affecting residents, visitors and the economy, both locally and nationally.

Figure 1: Management catchments and the strategic area in the South West river basin district

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During December 2015, Storms Desmond, Eva and Frank brought record breaking levels of rainfall and significant flooding to some parts of the country. On 5 and 6 December the highest ever river flows were registered in several large catchments including the Eden, Lune and Tyne. On 25 and 26 December further record river levels were registered for many large rivers draining the Pennines. The Met Office confirmed that December 2015 was the wettest on record in parts of the UK.

Across the country over 19,000 properties were flooded, with thousands more affected by loss of power supply and travel disruption. Existing flood defences played an essential part in protecting thousands of homes during December with 12,500 benefitting during Storm Desmond and 10,900 during Storm Eva. Support to affected communities, business and the agricultural sector is in place, along with a programme of inspections and repairs to damaged defences.

It is essential to ensure that we have the very best possible plans in place for flood management across the whole country. In response to the December floods the Government has put in place a National Flood Resilience Review pinpoint where our defences and modelling need strengthening. The Local Flood Partnerships in Cumbria and Yorkshire, also set up in response to the December floods, will bring together a wide range of organisations and communities to develop Flood Action Plans. These actions will complement the measures in the FRMP and the learning from this approach will be shared across the country.

Characteristics of the South West river basin district Dorset and Avon Hampshire management catchments The rivers in west Dorset are small, fast-reacting streams, where rainfall run-off travels quickly from hills either directly into the sea or into the Fleet (the lagoon behind Chesil beach). There are the wetlands of Radipole and Lodmoor and the unique coastal features of Portland Harbour, the Fleet Lagoon, Chesil beach and Lyme Bay. The River Frome (Figure 2) and the River Piddle drain from the North Dorset Downs, flowing through Dorset into Poole Harbour. The steep slopes inland lead to fast run-off after rain. The large, low-lying wetland areas around Poole Harbour help to disperse run-off from rain in this area. The Dorset Stour river starts in Stourhead gardens (Wiltshire) and flows Figure 2: River Frome in flood in the south-east to the English Channel at Christchurch Harbour. Wareham area of Dorset The water in rivers in the Hampshire Avon management catchment comes mainly from chalk aquifers. The rivers react slowly to rainfall because rain soaks into the ground and travels underground through the aquifer before it reaches the river. After long periods of very wet weather, the towns and villages between Salisbury and Christchurch can experience flooding lasting several weeks. North Devon, South Devon and East Devon management catchments The North Devon management catchment includes areas drained by the rivers Taw and Torridge and the north Devon coastal rivers. Steeply sloping tributaries (smaller rivers flowing into a bigger river) drain from the high ground of Exmoor and Dartmoor to the low-lying Taw and Torridge estuaries, or directly to the sea. Most of the properties at risk of flooding are in Barnstaple, Bideford and Braunton. The South Devon management catchment covers the catchments of the rivers Teign, Dart, Erme and Avon. Steeply sloping tributaries drain from the high ground of Dartmoor, to the wider valleys downstream and Figure 3: River Axe floodplain at Bow eventually into estuaries. Several small rivers drain the Torbay area. Bridge, Axminster Most of the properties at risk of flooding are in Torbay, Newton Abbot

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and Totnes. The East Devon management catchment includes the catchments of the rivers Exe, Sid, Otter, Axe, Lim and their tributaries. The land in the catchment varies, with steep, narrow valleys where the rivers start, that respond rapidly to rainfall. Further downstream there are wide flood plains that store large volumes of flood water (Figure 3). Most of the properties at risk of flooding are in Tiverton, Exeter and Exmouth. Tamar; North Cornwall, Seaton, Looe and Fowey; West Cornwall and the Fal (including the Isles of Scilly) management catchments The north and east of the Tamar catchment drains from Dartmoor, including the rivers Plym, Yealm and Lyd. To the west, the rivers Lynher, Ottery and Inny start on Bodmin Moor. In steeper areas, these tributaries react quickly to rainfall. The River Tamar is tidally influenced at Calstock and meets the sea at Plymouth Sound. Most properties at risk of flooding are in Plymouth, Plympton, Launceston and Tavistock. As the catchment is mainly rural properties are dispersed. This requires localised property protection combined with a catchment-based Figure 4: Coastal flooding at approach to help reduce flood risk. Perranporth, Cornwall The North Cornwall, Seaton, Looe and Fowey catchment includes the rivers Fowey and Camel. Both rivers start on the uplands of Bodmin Moor. Along the north coast there are many small, steep catchments, which respond rapidly to rainfall. Communities at risk of flooding here include Bodmin, Wadebridge, Boscastle and Bude. In the West Cornwall and the Fal catchment, there are many small, steep rivers which respond rapidly to rainfall. For towns such as Par and St Blazey, which are at risk of coastal, river and surface water flooding, risk management authorities will work in partnership together with the community manage flood risk. Changes within the mid-Cornwall china clay industry present a unique opportunity to provide many benefits to the area, for example restoring former china clay mines improves the environment for wildlife and people, and could also reduce flood risk downstream. The sea has a major influence on the landscape, economy and climate of the South West river basin district. Around the coast of Cornwall, tidal and coastal flooding is an issue for many small communities. Exposure to the storm conditions of the Atlantic means that these communities are particularly at risk of flooding and damage from high energy waves (Figure 4). This is the main flood risk on the Isles of Scilly and due to their remote location, they become isolated from external support in storms and require a high level of self reliance. Many coastal communities, including Plymouth, depend on historic breakwater structures for protection. Risk management authorities need to manage these defences carefully. Increasing flooding risk from climate change means that these coastal risks will increase, requiring strategic, community-led solutions to manage flood risk in locations such as Looe and Mounts Bay. South and West Somerset and the Somerset Levels and Moors strategic area The rivers in west Somerset drain the high ground of Exmoor down to the Somerset coast. High rainfall, combined with steep hills, leads to flooding of the river valleys. The Hawcombe Stream at Porlock, the Horner Water, the Allerford Brook at Allerford and Bossington, the lower part of the Washford River, and the upper catchment of the Monksilver Stream respond very quickly to any rainfall. These catchments are known as rapid response catchments. Most of the properties at risk of flooding in West Somerset are in Minehead, Porlock and Williton. Figure 5: Moorland flooding during winter 2014

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The rivers Brue and Axe start in the towns of Bruton and Wells respectively. Both rivers flow slowly through the flat lowlands of the Somerset Levels and Moors. They enter the sea at Highbridge (River Brue) and north of Brean Down (River Axe). Most of the properties at risk of flooding are in Wells, Glastonbury, Highbridge, Burnham-on-Sea and Weston-super-Mare. The River Parrett catchment drains from the Quantock, Blackdown and Polden hills. It flows through the Somerset Levels and Moors to the Bristol Channel at Bridgwater Bay. Most of the properties at risk of flooding are in Taunton, Wellington, Yeovil and Bridgwater. The Somerset Levels and Moors strategic area is part of the River Parrett catchment. It is a unique, low-lying wetland. Rainfall runs off the surrounding hills, slows and pools when it reaches the flat land of the Somerset Levels and Moors. The raised channels overflow, storing floodwater on the moors before it can reach the Parrett Estuary. The flat nature of the land combined with tide locking means the area drains very slowly and flood water cannot flow back to the river naturally. The area relies on a complex network of pumped drainage channels to remove floodwater. As a result, the area can suffer from prolonged flooding with many communities at high risk of flooding (Figure 5).

Existing flood risk management in the South West river basin district The Environment Agency operates a flood warning service for flood risk areas. More than 60,300 properties in the South West river basin district receive direct flood warnings. Of these, 28,700 have fully registered, which means people can specifically ask to receive warnings via text, mobile or to additional phone numbers. 31,600 have been automatically added to the flood warning service and will receive a warning via a landline telephone. Risk management authorities also work closely with local communities to help them prepare for and recover from floods. Across the country Government is investing £2.3bn on 1,500 flood defence schemes between 2015 -2021. Thousands of properties in the river basin district benefit from flood risk management schemes, including homes and businesses in Exeter and Perranporth. Further schemes are ongoing or planned in the South West river basin district, such as in Starcross and Cockwood, Bridgwater, Taunton, and West Bay. The National Flood Resilience Review will look at temporary and flexible responses as well as hard flood defences beyond the measures included in the Flood Risk Management Plan. The Local Flood Partnerships in Cumbria and Yorkshire, set up in response to the December floods will bring together a wide range of organisations and communities to develop Flood Action Plans. These actions will complement the measures in the FRMP and the learning from this approach will be shared across the country. The Environment Agency, local councils and the internal drainage boards also manage and reduce flood risk through the planning system. Planning officers use advice from the Environment Agency to assess new developments to make sure they are appropriate and safe, and will not increase the risk of flooding elsewhere.

Roles and responsibilities Managing flood and coastal risks, particularly local flood risks, requires risk management authorities to work together. In the South West river basin district, the Environment Agency works with 12 LLFAs, local councils, Highways England, internal drainage boards, and 5 water and sewerage providers.

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Table 1: risk management authorities by risk source Risk from: Environment Lead Local District Water Highway Internal Agency Flood /Borough company authority drainage Authority council board Main river  The sea  Surface water   Surface water (from highway)  Sewer flooding  Ordinary watercourse    Groundwater  Reservoirs * * * * * * Coastal Erosion   Strategic overview of all  sources of flood risk (and the coast)

*Please note RMAs have different responsibilities for reservoirs such as regulation, asset management and flood incident response

Objectives of the FRMP The risk management authorities have agreed social, economic and environmental objectives for 2015 to 2021 following discussion and consultation with other organisations and communities. You can see the objectives for the whole river basin district in section 9 of Part A of the FRMP. There are more detailed objectives for individual catchments, which you can see in section 3 of Part B of the FRMP. The FRMP objectives build on the aims and objectives in the ‘National flood and coastal erosion strategy for England’ (www.gov.uk/government/publications/national-flood-and-coastal-erosion-risk-management- strategy-for-england).

Measures for 2015 to 2021 The actions in FRMPs are known as ‘measures’. These are specific projects or investigations to work towards achieving the objectives. They explain where and how risk management authorities will focus effort and investment to reduce flood risk. The measures in FRMPs are grouped under 4 categories: preventing risk, preparing for risk, protecting from risk, and recovery and review. You can read more about the categories in Section 5 of Part A in the FRMP. Examples from the South West river basin district for each category

Preventing risk Measures in the South West river basin district to prevent flood risk include:  ensuring new development is appropriate, safe and does not increase flood risk elsewhere  carrying out hydraulic modelling (hydraulic modelling can tell us how deep the river water could be , if flooding occurs or the potential extent of flooding)

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 to improve understanding of how waves, tides and rivers affect one another  investigating ways to help communities adapt and protect critical infrastructure

Preparing for risk Examples of measures in the South West river basin district to prepare for risk include:  reducing flood risk through schemes and maintenance  working with communities to help them understand the risk and prepare effectively. This is particularly important in rapid response catchments, where is it not always possible to issue a flood warning in good time  informing and warning communities and business about flooding remains a priority  continuing to invest in real-time rainfall and river level data to provide a quality flood warning service

Protecting from risk These measures reduce the likelihood of flooding affecting people and property in specific locations. Measures to protect from risk include:  improving the standard of protection at important locations at risk of river and coastal flooding (including new schemes and renovating or upgrading existing defences)

 implementing individual property protection to residential properties

 realigning flood banks and creating habitat

Recovery and review Measures in the South West river basin district for recovery and review include:  continuing to carry out investigations after flooding, produce a recommendations report and help communities to recover from floods more quickly

The National Flood Resilience Review and Local Flood Action Plans may also give rise to actions that support the recovery of communities.

Further information on measures in the South West river basin district

For details of measures in each catchment see Part B of the FRMP. You can also see a full list of all measures and the categories they relate to in Part C of the FRMP.

Monitoring progress There is no guarantee that every measure in the FRMP will be completed. This is because priorities and funding change and new data may become available, which may mean the programme changes. Over the 6-year cycle, the Environment Agency will monitor implementation and report on progress. All the risk management authorities involved will work together to achieve the objectives and reduce costs.

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How we listened to your comments We ran a public consultation on the FRMP from 10 October 2014 to 31 January 2015. As a result of feedback from the consultation we have improved the information on existing flood risk management and made clearer links between the FRMP and river basin management plans. We’ve also shown more clearly how flood management actions help to improve the environment. We’ve split the FRMP into 4 sections to make it easier to understand. The sections are as follows: Section Who is the section for? Summary document For people who want a high level overview of the plan. Part A: background and river For people who want some legislative background and river basin basin district-wide information district-wide information. Part B: catchment summaries For people who want the detail of each of the catchments, flood risk areas and other strategic areas, and flooding statistics for the river basin district. Part C: appendices For people who want to see the measures for implementation across the river basin district and the measures for individual communities.

Further information about your flood risk Check your current risk of flooding on our live flood warning service (www.gov.uk/check-if-youre-at-risk-of- flooding) Check your risk of flooding from different sources on our interactive maps (www.gov.uk/prepare-for-a- flood/find-out-if-youre-at-risk) Find FRMPs for other river basin districts (https://www.gov.uk/government/collections/flood-risk- management-plans-frmps-2015-to-2021) Look at the river basin management plan for your area (https://www.gov.uk/government/collections/river- basin-management-plans-2015)

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Partners This is a plan prepared following consultation with the following risk management authorities:

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