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Exe Catchment Flood Management Plan Summary Report June 2012 managing flood risk We are the . 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.

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Environment Agency Manley House Kestrel Way 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 Exe Catchment Flood Management Plan (CFMP). This CFMP gives an overview of the flood risk in the Exe catchment and sets out our preferred plan for sustainable flood risk management over the next 50 to 100 years.

The Exe CFMP is one of 77 CFMPs for and The primary source of flooding in the Exe catchment is . Through the CFMPs, we have assessed inland from rivers, particularly where prolonged periods of flood risk across all of England and Wales for the first rainfall lead to a saturated catchment. There is also a time. The CFMP considers all types of inland flooding, risk of significant tidal flooding around the Exe from rivers, ground water, surface water and tidal and problems associated with tide-locking of the flooding, but not flooding directly from the sea (coastal tributary streams. The greatest number of people and flooding), which is covered by Shoreline Management properties at risk are in Exeter and Tiverton and on the Plans (SMPs). Our coverage of surface and ground towns around the estuary. Historically, it is in these water is however limited due to a lack of available locations that the greatest numbers of properties have information. been flooded in the past.

The role of CFMPs is to establish flood risk management We cannot reduce flood risk on our own, we will policies which will deliver sustainable flood risk therefore work closely with all our partners to improve management for the long term. This is essential if we the co-ordination of flood risk activities and agree the are to make the right investment decisions for the most effective way to manage flood risk in the future. future and to help prepare ourselves effectively for the We have worked with others including: County impact of climate change. We will use CFMPs to help us Council, , South West Water and the target our limited resources where the risks are National Farmers Union to develop this plan. greatest. This is a summary of the main CFMP document, if you This CFMP identifies flood risk management policies to need to see the full document an electronic version can assist all key decision makers in the catchment. It was be obtained by emailing produced through a wide consultation and appraisal [email protected] process, however it is only the first step towards an or alternatively paper copies can be viewed at any of integrated approach to Flood Risk Management. As we our offices in South West Region. 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 need to review parts of the CFMP.

Richard Cresswell South West Regional Director

Environment Agency Exe 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 Headwaters and high ground sub-area 12

2 Greater Exeter sub-area 14

3 Tiverton sub-area 16

4 sub-area 18

5 East of Exeter sub-area 20

6 sub-area 21

7 Mid Exe and Creedy sub-area 23

Map of CFMP policies 25

2 Environment Agency Exe 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 Exe Catchment Flood Management Plan 3 Catchment overview

The Exe CFMP comprises the In the north of the catchment, the The main areas of urban catchments of the and its Rivers Exe and Barle rise on the open development are to the south of the tributaries, as well as those of the wet of and flow catchment. In addition to Exeter, coastal streams that drain direct to south-east through steep sided these urban areas include Tiverton, the Exe estuary. The catchment wooded valleys. The rivers are Cullompton, (which is not at extends across several different confined within steep, narrow valleys risk of flooding), and the towns landscape types, from Exmoor in the that, in the upper reaches, respond around the Exe estuary, principally north, the wide floodplains and river rapidly to rainfall. to the east, and to valleys to the north of Exeter, to the the west. The remainder of the Then the Exe floodplain widens smaller tributary streams of the catchment is predominantly rural, through the gently undulating Devon estuary to the south. with smaller villages and minor landscape past Tiverton to Exeter. settlements, and is dominated by The area is environmentally rich, Just upstream of Exeter, the Exe is agriculture, particularly grazing. containing a large number of joined by two major tributaries, the statutorily designated sites. There Creedy, to the west, and the Culm, to The geology of the Exe catchment are two Areas of Outstanding Natural the east. The wide floodplains of the spans 400 million years. The oldest Beauty (AONB), three Special Areas lower reaches of the Exe and Culm rocks - siltstones, of Conservation (SAC), 31 Sites of provide considerable floodwater and shales - are in the Special Scientific Interest (SSSI), and storage, this attenuates and reduces uplands of Exmoor. Permo- 146 Scheduled Monuments. peak flows. sandstones, and breccias are found in the middle and The Exe CFMP covers an area of some The Exe finally flows into the Exe eastern parts of the catchment. With 1,500 square kilometres (580 square estuary immediately to the south of sands and muds being deposited in miles). Annual rainfall ranges from Exeter. The and a number the Exe Estuary as the most recent more than 2,300mm (90in) in upland of smaller tributary streams also flow geological activity. areas to less than 800mm (32in) on directly into the estuary, both to the the coast - the England and Wales west and to the east. average is 920mm (36in).

4 Environment Agency Exe Catchment Flood Management Plan Map 1. Location and extent of the Exe CFMP area

Legend

Exe CFMP Urban areas

Main rivers Railway Wellington Motorway

Tiverton Cullompton

Crediton N

Exeter

Sidmouth

Bovey Tracy Exmouth Dawlish 0 4 8 12 16 Kilometres

© Crown Copyright. Environment Agency 100026380.

➜ Coastguards rescue residents from a flooded caravan park at in December 2000 Photo: Guy Newman/Apex

Environment Agency Exe 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 There is also a risk of significant The main risks to people, property chance (probability) of a particular tidal flooding around the estuary, and the environment across the flood and the impact (or with problems associated with tide- catchment are from the rivers and consequence) that the flood would locking of the tributary streams. the tide. have if it happened. The probability The greatest number of people and In total, approximately 11,000 of a flood relates to the likelihood of property at risk is from the River Exe properties in the Exe catchment are a flood of that size occurring within a in Exeter and Tiverton, and the at risk from a 1% annual probability year period. It is expressed as a towns around the Exe estuary, flood. This assumes there are no percentage. For example, a 1% flood particularly Exmouth. Historically, it defences. This represents 10% of all has a 1% chance or 0.01 probability is in these locations that the properties in the Exe catchment. of occurring in any one year, and a greatest numbers of properties have However, this also includes key 0.5% flood has a 0.5% chance or been flooded. community assets such as schools, 0.005 probability of occurring in any care homes, ambulance, police and one year. The most significant recorded floods fire stations, health centres and a occurred in 1960, when severe Hydraulic modelling, to determine hospital. flooding in Exeter affected more flood extent, depth and velocity, was than 1,000 properties. It was as a Numerous sites designated for their carried out for the River Exe result of this flooding that the natural or historic environmental upstream as far as the confluence current flood alleviation scheme in value are also affected by flooding, with the River Batherm at Bampton, Exeter was constructed. including the Exe Estuary Ramsar, a the upstream to Special Protection Area (SPA) and . This ensured coverage of Our current flood risk management SSSI site. the main urban areas at risk: Exeter, activities are focussed on the key Tiverton and Cullompton, as well as sites and ensure the continuing The main rail line to the South West other settlements along these maintenance and operation of the near Exeter and along the Exe reaches. In areas outside the extent flood defences. With the Exeter, estuary is at risk of flooding, as are of our model coverage, we have Tiverton and Exmouth defences in the main water and waste water used Flood Zone 2 and Flood Zone 3 place, estimated annual average treatment works at Exeter. outlines. damages for the towns are reduced to less than a third of what they The primary source of flooding in the would be without defences. Exe catchment is from rivers, particularly when prolonged periods of rainfall fall on saturated ground.

6 Environment Agency Exe Catchment Flood Management Plan Map 2. Flood risk to property in a 1% annual probability river flood, taking into account current flood defences

Legend

Properties with a 1% chance of flooding 150 - 500 501 - 1,000 1,001 - 2,000 Bampton 2,001 - 3,000

Tiverton 3,001 - 4,000

Exe CFMP Cullompton Main rivers N

Exeter

Topsham

Starcross Dawlish Warren Exmouth

0 4 8 12 16 Kilometres

© Crown Copyright. Environment Agency 100026380.

Table 1. Locations of towns and villages with 100 or more properties at risk in a 1% annual probability river flood

Number of properties at risk Locations

2,000 to 5,000 Exeter, Exmouth

1,000 to 2,000 Tiverton

500 to 1,000

250 to 500 Dawlish Warren, Cullompton

100 to 250 Stoke Canon and Cowley, Bampton, Dawlish, Exminster, Lympstone, Topsham

Table 2. Critical infrastructure at risk:

55 electricity substations, 4 water treatment works, 5 railway lines, 5 A roads, and 1 motorway

Environment Agency Exe Catchment Flood Management Plan 7 Where is the risk? How we currently manage the risk

The distribution of potential flood Our activity is prioritised on a risk Incident Plans have been risk from rivers and tides is basis. Our main activities include: developed for specific areas of illustrated in Map 2 for a flood with a Exeter and Tiverton. • Flood risk mapping – A major part 1% annual probability (0.5% for of the programme is Flood Zone • Flood defence schemes – We tides) of occurring or being Improvements and Hazard have flood defences on the River exceeded. Mapping. This is focused on Exe including at Exeter, on the In addition to Exeter, Tiverton and improving the mapping at high- rivers Creedy, Yeo, Culm, Clyst and Exmouth, floods have also affected risk locations. Alphin Brook, and at , significant numbers of properties, Bampton, Tiverton, Exmouth, • Managing development – Our for example in Stoke Canon, Lympstone and Dawlish. development control team Bampton, Cullompton, supports the planning process by • Maintenance – This includes and Dulverton. ensuring that new developments maintenance of banks and In addition to these locations, there have the appropriate flood risk structures, desilting, clearance of are risks of surface water flooding. assessments and follow PPS25 obstructions and embankment However, further studies following (Government Planning Policy maintenance. Spending is divided on from the CFMP are needed by us Statement on Development and almost equally between works in and our partners to quantify this Flood Risk). the channel to maintain flow potential risk. capacity and works to bank • Flood warning – A warning system structures. The Exe and Exe in place for Exeter and Tiverton Estuary account for 67% of includes loudhailers and leaflet maintenance spending; the drops. Elsewhere in the reminder is used for other main catchment, registered properties river systems including the Culm, receive a direct message via Creedy and Clyst. Local phone, email or fax. Major authorities carry out a large amount of further work.

➜ The railway embankment at Cowley Bridge near Exeter was washed away by the River Exe just after it had been repaired following an earlier flood Photo: Mark Hill/Apex

8 Environment Agency Exe Catchment Flood Management Plan The impact of climate change and future flood risk

In the future, flooding will be probability flood, rising from the time it takes flows to peak, showed influenced by climate change, current 8,800 properties. Flood risk that the expected increase in flows changes in land use (for example, from rivers increases mainly in the would be up to 5%. urban development) and rural land communities of Exeter and Tiverton. We have therefore based our management. In the Exe catchment, The sensitivity testing undertaken modelling of future flood risk on climate change is expected to have showed that urban development climate change, urban development the greatest impact on flood risk. The could affect flood risk in the and land management. following future scenario for climate communities of Exeter and Tiverton. change was used in the CFMP: We found that with estimates of • 20% increase in peak flow in all increased urban area around these watercourses. This will increase communities, based on Local the probability of large-scale flood Authority Development Plans, flows events, would be expected to increase by 2%. For the Clyst and • a total sea level rise of 950mm by catchments, which include the East the year 2100. This will increase of Exeter growth areas, flows would the probability of tidal flooding be expected to increase by 5%. With around the Exe estuary. the rural nature of much of the Using river models we estimate that catchment we found that run-off from by 2100, around 10,950 properties agricultural land plays a part in flood in the key settlements (Figure 2) may risk. An expected increase in run-off, be at risk from a 1% annual combined with a reduction in the

Figure 2. Current and future (2100) flood risk to property from a 1% annual probability river flood, taking into account current flood defences

5000

4000

3000

2000

1000 Number of Properties at Flood Risk at Properties Number of

0 ExeterLower Estuary TivertonUpper Estuary Stoke Canon Cullompton Bampton Clyst St Mary and Cowley and Current Future

Environment Agency Exe Catchment Flood Management Plan 9 Future direction for flood risk management

Approaches in each sub-area

We have divided the Exe catchment into seven distinct sub-areas which have similar physical characteristics, sources of flooding and level of risk. We have identified the most appropriate approach to managing flood risk for each of the sub-areas and allocated one of six generic flood risk management policies, shown in Table 3.

To select the most appropriate policy, the plan has considered how social, economic and environmental objectives are affected by flood risk management activities under each policy option.

➜ Flood waters swell the River Exe in December 2000 Map 3. Exe sub-areas

Combe Martin Legend Woolacombe Exe CFMP

Braunton Sub-area Barnstaple 1 Headwaters and highground (Policy 6) 2 Greater Exeter (Policy 5) South Molton 3 Tiverton (Policy 5) 4 Wellington Cullompton (Policy 5) 5 East of Exeter (Policy 4) 6 Exe Estuary (Policy 4) Tiverton 7 Mid Exe and Creedy (Policy 2) Chard Cullompton 8 9

Crediton Honiton N

Okehampton West Hill Exeter Seaton Lyme Regis

Budleigh Salterton Exmouth Dawlish 0 4 8 12 16 Kilometres Ashburton © Crown Copyright. Environment Agency 100026380. ik ll

10 Environment Agency Exe Catchment Flood Management Plan Table 3. Policy options Policy 1 Areas of little or no flood risk where we will continue to monitor and advise This policy will tend to be applied in those areas where there are very few properties at risk of flooding. It reflects a commitment to work with the natural flood processes as far as possible.

Policy 2 Areas of low to moderate flood risk where we can generally reduce existing flood risk management actions This policy will tend to be applied where the overall level of risk to people and property is low to moderate. It may no longer be value for money to focus on continuing current levels of maintenance of existing defences if we can use resources to reduce risk where there are more people at higher risk. We would therefore review the flood risk management actions being taken so that they are proportionate to the level of risk.

Policy 3 Areas of low to moderate flood risk where we are generally managing existing flood risk effectively This policy will tend to be applied where the risks are currently appropriately managed and where the risk of flooding is not expected to increase significantly in the future. However, we keep our approach under review, looking for improvements and responding to new challenges or information as they emerge. We may review our approach to managing flood defences and other flood risk management actions, to ensure that we are managing efficiently and taking the best approach to managing flood risk in the longer term.

Policy 4 Areas of low, moderate or high flood risk where we are already managing the flood risk effectively but where we may need to take further actions to keep pace with climate change This policy will tend to be applied where the risks are currently deemed to be appropriately-managed, but where the risk of flooding is expected to significantly rise in the future. In this case we would need to do more in the future to contain what would otherwise be increasing risk. Taking further action to reduce risk will require further appraisal to assess whether there are socially and environmentally sustainable, technically viable and economically justified options.

Policy 5 Areas of moderate to high flood risk where we can generally take further action to reduce flood risk This policy will tend to be applied to those areas where the case for further action to reduce flood risk is most compelling, for example where there are many people at high risk, or where changes in the environment have already increased risk. Taking further action to reduce risk will require additional appraisal to assess whether there are socially and environmentally sustainable, technically viable and economically justified options.

Policy 6 Areas of low to moderate flood risk where we will take action with others to store water or manage run-off in locations that provide overall flood risk reduction or environmental benefits This policy will tend to be applied where there may be opportunities in some locations to reduce flood risk locally or more widely in a catchment by storing water or managing run-off. The policy has been applied to an area (where the potential to apply the policy exists), but would only be implemented in specific locations within the area, after more detailed appraisal and consultation.

Environment Agency Exe Catchment Flood Management Plan 11 Sub-area 1

Headwaters and high ground

Our key partners are: The 1% flood also affects the A396 natural features to develop in the along the Exe valley, the police and floodplain, this policy could also West District Council fire stations in Dulverton; as well as enhance landscape character. two care homes, two electricity sub- Though this policy involves a District Council stations and two telephone strategic increase in flooding in exchanges. District Council allocated areas, it is not intended to adversely affect the risk to Exmoor National Park individual communities. We will AONB The vision and continue with our current preferred policy maintenance activities in locations Natural England where the numbers of people and Policy Option 6 - we will take action property at risk are high (for with others to store water manage example, Bampton and Dulverton). The issues in this run-off in locations that provide sub-area overall flood risk reduction or environmental benefits.

This sub area covers the There is considerable potential to predominantly rural headwaters and attenuate and reduce floodwater high ground of the Exe catchment. It through changes in land use and includes parts of Exmoor which land management. Opportunities drain to the south. It includes the include creating wetland features River Batherm catchment, the upper and increased tree and hedge Culm catchment and the upper Clyst planting across the floodplain. catchment (excluding the East of Exeter area). Our assessment of catchment hydrology has identified that the Flood risk is dispersed across this upper Culm catchment is the most area, with approximately 2,000 effective location for changes in people and 800 properties within land use and land management to the 1% annual probability flood reduce peak flows downstream. extent. The majority of these are in However, taking action on Exmoor, Bampton and Dulverton where flood and in the Lowman and upper Clyst defence schemes for a 7% and 2% catchments is also likely to have an flood event, respectively, are in effect if carried out over large areas place. There are also significant of land. numbers of properties at risk elsewhere, for example in Exford, These changes could potentially , and . reduce the flood risk to urban areas Flood defences are present in these further downstream, such as Exeter, locations, we estimate Tiverton and Cullompton as well as approximately 1,150 properties will benefiting Biodiversity Action Plan be within the 1% flood extent by habitats and species. By allowing 2100.

12 Environment Agency Exe Catchment Flood Management Plan Proposed actions to implement the preferred policy

• Identify where environmental enhancements will bring the greatest flood risk benefits. Investigate if the lower Culm can provide opportunities for compensatory habitat if sea level rise affects existing high tide roost sites.

• Work with Natural England and others to promote better land management practices.

• Work with partners to use naturalistic features to attenuate surface water flows and manage flood riske.g. Exmoor Project, Exmoor Mires project, tree planting and buffer strips, floodplain hedgebanks.

• Ensure land drainage consenting promotes restoration of meanders, rather than hold the current line with hard revetment.

• Continue with current maintenance activities in appropriate locations where the numbers of people and properties at risk are high (for example, in Bampton and Dulverton).

• Reduce amount and frequency of gravel removals returning gravels to headwaters upstream.

• Monitor hydraulic performance of Bampton flood defence improvements and Shuttern Brook.

• Investigate if the can be used for flood storage.

• Identify locations and reduce risk to life from cars becoming stuck in floodwaters in fords and ‘Irish bridges’ (for example, by reviewing signage, depth boards).

• Improve awareness and resilience in communities at risk of fast onset flooding with deep and fast flows. Assess if works to reduce the flood risk are possible.

• Engage with landowners to influence land use changes to deliver flood risk, biodiversity and water quality benefits. This might involve field scale trials together with a review of the existing knowledge base.

• Increase floodplain storage and attenuation by increasing wetland habitat, wet woodland (notably at Bampton and Dulverton) and hedge planting across the floodplain.

• Oppose inappropriate development within Flood Zone 3 (1% flood extent).

• Investigate ways in which people can be moved out of risk areas. Investigate also if critical infrastructure can be moved out of risk areas.

Environment Agency Exe Catchment Flood Management Plan 13 Sub-area 2

Greater Exeter

Our key partners are: schools and health centres in St The vision and Thomas; and Listed Buildings in preferred policy Exeter and Stoke Canon. Infrastructure at risk of flooding Policy Option 5 - we can generally includes more than 30 electricity take further action to reduce flood sub-stations, the main railway line, East Devon District Council risk. Pynes Water Treatment Works and South West Water Countess Wear Waste Water The Policy chosen would ensure Treatment Works and the A377and some continued protection to the Network Rail A379 roads. In the future we schools, health centres and other Natural England estimate that 4,000 properties will critical infrastructure such as the be at risk from a future 1% annual ambulance station, electricity probability flood. substations, and the care homes within the flood extent. The issues in this Defences in Exeter and Stoke Canon sub-area were constructed in the 1960s and Taking further action to reduce flood 1970s following flooding in Exeter risk would protect the Exe Estuary in 1960. The defences in Exeter are The area covers the urban extent of SSSI / SPA / Ramsar site from designed to a 1% annual Exeter, including , St Thomas, pollution resulting from flooding. probability standard of protection. Ide, Alphington and Marsh Barton This policy would help to manage Due to a possible low point in Industrial Estate to the west. To the the risk to historic features within defences at Station Road in Exeter north, it includes Stoke Canon at the area, such as Exeter Quay, the actual standard of protection the confluence of the rivers Exe and although scheduled bridges may may be lower than this at around Creedy. To the east, and south, this remain vulnerable to damage. 3.3%. The standard of protection of extends as far as the . the defences in Stoke Canon is 4%. At least 7,000 people and 3,000 A flood warning service is in place in properties are within the 1% annual Exeter with a lead time of probability flood extent for the River approximately four hours. A Major Exe in Exeter. The majority of these Incident Plan covering fluvial are in the St Thomas area of Exeter. flooding from the Exe is in place. At risk of flooding are: two care homes and an ambulance station;

14 Environment Agency Exe Catchment Flood Management Plan Proposed actions to implement the preferred policy

• Carry out a modelling study to investigate how the flow contributions of the tributaries combine at Exeter.

• Investigate how we can improve the environmental and flood risk management performance of our existing systems through Exeter and Stoke Canon.

• Improved flood forecasting and engagement of local partners and community in flood awareness, incident management, and emergency response.

• Evaluate risk to critical infrastructure, especially between Exeter and Stoke Canon: Pynes WTW and mainline railway

• Investigate the risk of flooding to the waste water treatment works in Stoke Canon, Countess Weir, and the main sewer along the Exeter canal embankment in relation to Flood Risk Management works.

• Work with partners to retro-fit SuDs in problem areas. Including identifying and retro-fitting SuDs where problems of highways drainage entering sewerage systems have been identified.

• Ensure spatial planning and development does not increase flood risk (PPS25).

• Investigate ways in which people can be moved out of risk areas over the lifetime of the CFMP.

• Investigate opportunities to restore areas of the North Brook and Pin Brook in Exeter, both to provide environmental enhancements and to reduce flood risk.

• Investigate locations and routes for to find compensatory high water roosts as the estuary changes and whether this can also provide flood risk benefits. In particular investigate land between Exwick Radial Gates and Cowley Bridge for this and for flood attenuation/washlands.

➜ Okehampton Street in Exeter turns into a river in the 1960 floods.

Environment Agency Exe Catchment Flood Management Plan 15 Sub-area 3

Tiverton

Our key partners are: estimate that 1,500 properties will The vision and be at risk from a future 1% annual preferred policy Mid Devon District Council probability flood.

Devon County Council The River Lowman’s catchment is Policy Option 5 - we can generally much smaller and more ‘flashy’ take further action to reduce flood Emergency Planners than the Exe. The standard of risk. protection of defences from the Primary Care Trust By taking further action, the 1,500 Lowman is also lower than for the properties and 3,500 people within South West Water Exe. So although approximately the future 1% flood extent would three-quarters of the properties at see their risk of flooding reduced, as risk from flooding in Tiverton are at would the schools, hospitals and risk from the Exe and only one other critical infrastructure including The issues in this quarter from the Lowman, overall the fire station, electricity sub- sub-area we consider the consequences of station and a care home. flooding to people is generally Areas of Tiverton are at risk of greater for the Lowman than for the There would still be a risk to flooding from the River Exe and Exe. approximately 1,700 properties and River Lowman. In total, 4,000 people from an extreme 0.1% Flood defences on the Exe and the approximately 3,000 people and flood event. In practice this Lowman comprise flood walls, 1,400 properties are within the 1% magnitude of flooding cannot be channel improvements and weirs. flood extent. Of these, reasonably engineered against. These provide a standard of approximately 900 people are protection of 1% on the Exe, and estimated to be at risk from a 2% on the Lowman. Some third significant or extreme flood hazard party flood risk infrastructure has of deep and fast flowing floodwater. been put in place on the Lowman as Furthermore, 44 Listed Buildings, a part of more recent development. Tiverton Hospital, two schools, a fire station, a care home, a number of A flood warning service is in place in electricity sub-stations, and parts of Tiverton – current flood warning the A3126 and A396 roads are at lead time is approximately two risk from a 1% annual probability hours for the River Exe but only one flood. A quarter of the Tidcombe hour for the River Lowman. A Major Lane Fen SSSI is within the current Incident Plan covering fluvial 1% floodplain. In the future we flooding is in place in Tiverton.

16 Environment Agency Exe Catchment Flood Management Plan Proposed actions to implement the preferred policy

• Investigate how we can improve the performance of our existing systems.

• Investigate ponding of water behind defences in Tiverton.

• Improved flood forecasting and engagement with local partners and community in flood awareness, incident management, and emergency response.

• Ensure spatial planning and development does not increase flood risk (PPS25). There may be an opportunity for improvements to be made to reduce flood risk as part of new developments (for example, developments next to the Lowman). As part of ma naging fu tu re flood risk to new developments, the local authority may specify a sum of money to be retained specifically for future maintenance purposes.

• Eva luate risk to cr itical infrastructure: hospital, school, wa ter and sewa ge treatment works and evacuation centres. Invest igate if cr itical infrastructure ca n also be moved out of risk areas.

• Investigate ways in which people can be moved out of risk areas.

• Investigate if we can use land next to the River Lowman for flood storage.

• Ensure private flood risk infrastructure is maintained.

• Work with partners to retro-fit SuDs in problem areas. Including identifying and retro-fitting SuDs where problems of highways drainage entering sewerage systems have been identified.

• Investigate measures upstream to reduce the flood risk. Look at ways of influencing land use and land management practices in the Lowman catchment.

• Improve awareness and resilience in communities at risk of fast onset flooding with deep and fast flows, and assess if works to reduce the flood risk are possible.

➜ Flooding on the south side of Tiverton

Environment Agency Exe Catchment Flood Management Plan 17 Sub-area 4

Cullompton

Our key partners are: We estimate approximately 170 The vision and properties and 400 people will be preferred policy Mid Devon District Council within the future 1% flood extent from the River Culm. A further 400 Policy Option 5 - we can generally National Farmers Union properties and 800 people are take further action to reduce flood within the 1% flood extent from the Natural England risk. tributaries. Land Owners We consider the risk from the In some areas of Cullompton, the tributaries associated with, for streams have been culverted example, potential blockages to through housing estates that were culverts, to be currently The issues in this built in the 1970’s. This can result in unacceptable. sub-area flooding from culverts blocked with debris during high flows, as By taking further action to reduce The Cullompton area includes all of occurred during flooding in 2002. risk, we propose to take measures urban Cullompton to the west of the Defences in Cullompton for the River toresolve these issues both by River Culm extending to Stoneyford Culm consist of channel opening up culverted sections to in the east, and approximately 5km improvements, flood relief culverts reduce the risk of blockages, and north to include , between and flood banks. These provide a also over the longer term to the Culm and Spratford Stream. 1.7% Standard of Protection. investigate ways in which people can be moved out of the risk areas. The greatest flood risk in Cullompton The River Culm has a relatively slow is from the various tributary streams response to rainfall. Flood warning that flow through the town into the for Cullompton has a lead time of Culm. The catchments for these approximately two hours. The flood tributary streams are small and hazard is low for the majority of respond rapidly to rainfall. properties.

We estimate that 450 properties and There is likely to be a large amount 1050 people are at risk from the 1% of residential and commercial annual probability flood of the River development in the Cullompton area Culm and its tributaries. In addition in the future, commercial pressure to the risk to people and property, driven to some extent by distribution junctions of the M5 motorway, the centres around the motorway A373 and B3181, the main line junction. railway and a sewage works are also at risk from the 1% flood. An ambulance station and two care homes are also at risk of flooding.

18 Environment Agency Exe Catchment Flood Management Plan Proposed actions to implement the preferred policy

• Investigate the River Culm and Spratford Stream response to high flows – particularly the interaction of flows with the M5, and the railway. Identify if hedge and floodplain woodland planting can attenuate flows.

• Prepare an Asset Management Plan to identify where future works may be required to reduce risk to Cullompton.

• Work with partners to manage surface water flooding in Cullompton, particularly for new development. Incorporate use of Sustainable Drainage Systems (SuDS).

• Investigate improvements to the tributaries to provide environmental enhancements and to reduce risk of blockage to culverted sections. Examine the possibility of opening up culverted sections.

• Investigate ways in which people and infrastructure can be moved out of risk areas.

• Ensure spatial planning and development does not increase flood risk (PPS25).

• Improved flood forecasting and engagement with local partners and community in flood awareness, incident management, and emergency response. Investigate if some level of flood warning coverage may be feasible on the tributary streams.

• Engage landowners to influence land use and land management practices in the upper Culm catchment.

➜ Flooding of the Leather dressing works, Alexandria Industrial Estate, Cullompton - January 1984

Environment Agency Exe Catchment Flood Management Plan 19 Sub-area 5

East of Exeter

Our key partners are: We estimate that approximately 90 Proposed actions to properties will be in the future 1% implement the preferred East Devon District Council flood extent. Fluvial flood risk will remain a relatively low hazard. policy Exeter City Council Exeter is considered both a • Work with developers and the Natural England Strategically Significant City and a local authority to ensure new Principal Urban Area by the South National Farmers Union development complies with West Regional Spatial Strategy. As PPS25. Land Owners such it will be a focus for future development, in particular the new • Complete the Green town of Cranbrook in East Devon, Infrastructure Study to maximise and possible expansion of the environmental and recreational The issues in this airport and a new rail freight use of the floodplain. sub-area terminal. • Influence land use and land management practices in the The East of Exeter area is a Clyst catchment, which is predominantly rural area The vision and relatively shallow and low lying immediately to the east of the city. It and has the potential to reduce extends as far as the M5 motorway preferred policy and attenuate peak flows by to the west, to the north, Policy Option 4 - we are already holding back floodwater. Rockbeare to the east and Clyst St managing the flood risk effectively, Mary to the south, and also includes but we may need to take further and the nearby actions to keep pace with climate business park. The area will see change. substantial future development. Future flood risk will be largely At present, approximately 50 determined by new development, properties in the area (in Broadclyst which consequently must be and Clyst Honiton) are within the 1% carefully designed to avoid any long annual probability flood extent of the term impacts. River Clyst. This generally presents a low hazard and a flood embankment in Clyst St Mary provides a 4% standard of protection.

20 Environment Agency Exe Catchment Flood Management Plan Sub-area 6

Exe Estuary

Our key partners are: In total, around 2,600 properties The vision and and 6,000 people are in the 1% preferred policy District Councils annual probability fluvial and 0.5% tidal flood extent. Exmouth Policy Option 4 - we are already East Devon District Council accounts for over half of this total. A managing the flood risk effectively, number of health centres and Network Rail but we may need to take further schools are within the 1% flood actions to keep pace with climate Devon County Council extent as are care homes, Listed change. Buildings and a number of Highways Agency electricity sub-stations. Within this sub-area there are opportunities to both retain existing South West Water Approximately 2,300 properties are defences in certain locations and to within the 10% flood extent. The Natural England look at investigating how we can current standard of protection of move people and infrastructure out National Farmers Union fluvial defences in the Exe estuary of the risk areas. The actions chosen towns is greater than this. will allow us to keep pace with We estimate approximately 2,800 climate change. The issues in this properties will be in the future 10% sub-area flood extent. In general the catchments for the The Exe Estuary covers the towns tributary streams are small and fast and infrastructure around the Exe responding. Changes in land use estuary as far as the M5 viaduct. To upstream can have an impact on the west of the estuary this includes flood risk. The greatest fluvial flood Dawlish, Dawlish Warren, risk typically occurs at the lower end Cockwood, Starcross, Kenton and of these tributaries where peak flow Exminster. To the east of the estuary events in the watercourses coincide it includes Exmouth, Lympstone, with tide-locking in the estuary. Exton and Topsham. The Exe Estuary is a SSSI, a SPA and a Ramsar site Whilst there are both fluvial and and includes the Dawlish Warren, tidal flood risks, direct tidal risks SSSI, SAC and National Nature are addressed by the Shoreline Reserve. Management Plan and are likely to play the greatest role in the future of coastal designated sites.

Environment Agency Exe Catchment Flood Management Plan 21 Proposed actions to implement the preferred policy

• Investigate ways that existing flood defence schemes in urban areas can be managed, taking into account flow and sea level rise since their construction, and in particular considering issues of tide- locking.

• Improved flood forecasting and engagement with local partners and community in flood awareness, incident management, and emergency response.

• Work with partners to retro-fit Sustainable Drainage Systems in problem areas. Identify problems where highways drainage enters sewerage systems and retro-fit Sustainable Drainage Systems .

• Ensure spatial planning and development does not increase flood risk (PPS25). This should include consideration of climate change adaptation as directed in Planning Policy Statement 1.

• Investigate ways in which people and infrastructure can be moved out of risk areas. The location of mobile homes / caravan parks in the Dawlish Warren area must be considered. Local Development Framework documents should identify areas where future river and floodplain restoration may be considered especially for locations of present mobile homes and/or caravan parks.

• Investigate measures upstream to reduce the risk. Engage landowners to influence land use and land management practices in the catchments within and upstream of the estuary area.

• Improve awareness and resilience in communities at risk of fast onset flooding with deep and fast flows, and assess if works to reduce the flood risk are possible.

22 Environment Agency Exe Catchment Flood Management Plan Sub-area 7

Mid Exe and Creedy

Our key partners are: Properties that are at risk are The vision and generally dispersed throughout the preferred policy Teignbridge District Council area, although in total approximately 800 people and 300 Policy Option 2 - we will generally Mid Devon District Council properties are within the 1% annual reduce existing flood risk probability flood extent. We East Devon District Council management actions. estimate approximately 50 people Devon County Council are at risk from deep and fast In general, the flood risk is relatively flowing floodwater. minor and dispersed. There are Natural England locations where we carry out A number of main roads and the maintenance work, and to cease Farmers and Landowners railway line through Crediton are any flood risk management also at risk of flooding, although activities altogether would lead to there is little other critical an unacceptable localised risk. In infrastructure at risk. The issues in this these few locations where the sub-area There are few flood defences within numbers of people at risk are the area. A small amount of concentrated we would continue This rural area covers the mid Exe maintenance debris removal current or alternative maintenance, and Creedy catchments and the desilting is carried out. but overall we would look to reduce area to the west of the Exe estuary. activities.

The largest community, Crediton, is The Creedy is a relatively fast, steep located on high ground between the river draining a classic undulating and the River Yeo and Devon landscape. There may be is not at risk of flooding. some localised opportunities for retention of floodwater, but these are not extensive.

Environment Agency Exe Catchment Flood Management Plan 23 Proposed actions to implement the preferred policy

• Review current maintenance activities to identify where they can be reduced to allow the floodplain to naturalise with potential biodiversity benefits. Continue with current or alternative maintenance activities where the numbers of people and properties at risk are high.

• Reduce amount and frequency of gravel removals. Return gravels to headwaters as a routine part of these works.

• With Natural England and others, promote improved land management practices.

• Investigate if embankments can be reduced where doing so would provide a flood risk benefit.

• Ensure that Land Drainage consenting promotes restoration of meanders where appropriate, and allows the river to reclaim floodplain.

• Investigate ways in which people and infrastructure can be moved out of risk areas.

• Oppose inappropriate development within Flood Zone 3 and work to ensure that local authorities implement PPS25. Local Development Frameworks should consider designating all floodplain areas as functional floodplain.

• Any flood risk management systems required for new communities or any other developments are not expected to be maintained or adopted by the Environment Agency. However, we may need to consider improvements where the number of people at risk are concentrated.

• With Devon County Council identify locations and reduce risk to life due to cars becoming stuck in floodwaters at fords and ‘Irish bridges’.

➜ Floods from the River Exe surround a cottage at Bickleigh near Tiverton in December 1994

24 Environment Agency Exe Catchment Flood Management Plan Map of CFMP policies

Map of the policies in the Exe catchment Legend Williton Exe CFMP Main rivers

Urban areas

Preferred approach South Molton Policy 1 Policy 2 1 Wellington Policy 3 Tiverton Policy 4 Policy 5 3 Cullompton Policy 6 4 Crediton Honiton N Okehampton 7 5 Exeter 2

6 Bovey Tracy Exmouth Dawlish 0 4 8 12 16 Kilometres Teignmouth

© Crown Copyright. Environment Agency 100026380.

The sub-areas

1 Headwaters and high ground 2 Greater Exeter 3 Tiverton 4 Cullompton 5 East of Exeter 6 Exe Estuary 7 Mid Exe and Creedy

Environment Agency Exe Catchment Flood Management Plan 25 Would you like to find out more about us, or about your environment?

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