East Devon Catchment Flood Management Plan · the Axe, maintaining flow through dry periods. The...

managingflood risk

Summary Report June 2012

East Devon Catchment Flood Management Plan

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June 2012

Environment Agency East Devon Catchment Flood Management Plan 1

Introduction

I am pleased to introduce our summary of the East Devon

Catchment Flood Management Plan (CFMP). This CFMP gives an

overview of the flood risk in the East Devon catchment and sets out

our preferred plan for sustainable flood risk management over the

next 50 to 100 years.

The East Devon CFMP is one of 77 CFMPs for Englandand Wales. Through the CFMPs, we have assessedinland flood risk across all of England and Wales for thefirst time. The CFMP considers all types of inlandflooding, from rivers, ground water, surface water andtidal flooding, but not flooding directly from the sea(coastal flooding), which is covered by ShorelineManagement Plans (SMPs). Our coverage of surfaceand ground water is however limited due to a lack ofavailable information.

The role of CFMPs is to establish flood risk managementpolicies which will deliver sustainable flood riskmanagement for the long term. This is essential if weare to make the right investment decisions for thefuture and to help prepare ourselves effectively for theimpact of climate change. We will use CFMPs to help ustarget our limited resources where the risks aregreatest.

This CFMP identifies flood risk management policies toassist all key decision makers in the catchment. It wasproduced through a wide consultation and appraisalprocess, however it is only the first step towards anintegrated approach to Flood Risk Management. As weall work together to achieve our objectives, we mustmonitor and listen to each others progress, discusswhat has been achieved and consider where we mayneed to review parts of the CFMP.

Flooding in the East Devon catchment is mainly fromrivers but there is also the risk of significant tidalflooding in communities along the coast. Risks topeople, property and infrastructure are concentrated inSeaton, Sidmouth, Honiton, Axminster, Ottery St Mary,Budleigh Salterton and Newton Poppleford. There hasbeen widespread flooding across the catchment, mostnotably in 1968 and 2000.

We cannot reduce flood risk on our own, we willtherefore work closely with all our partners to improvethe co-ordination of flood risk activities and agree themost effective way to manage flood risk in the future.We have worked with others including: Devon CountyCouncil, Natural England, South West Water and theNational Farmers Union to develop this plan.

This is a summary of the main CFMP document, if youneed to see the full document an electronic version canbe obtained by emailing [email protected] alternatively paper copies can be viewed at any ofour offices in South West Region.

Richard CresswellSouth West Regional Director

2 Environment Agency East Devon Catchment Flood Management Plan

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 Upper Otter and Axe sub-area 12

2 Axe and Otter Estuaries sub-area 14

3 Budleigh Salterton sub-area 16

4 Seaton sub-area 18

5 Sidmouth and Lyme Regis sub-area 20

6 Otter St Mary sub-area 22

7 Axminster and Honiton sub-area 23

8 Rural Mid and Lower catchment sub-area 25

Map of CFMP policies 27

Contents


The purpose of a CFMP in managing flood riskCFMPs help us to understand thescale and extent of flooding now andin the future, and set policies formanaging flood risk within thecatchment. CFMPs should be used toinform planning and decisionmaking by key stakeholders such as:

• the Environment Agency, who willuse the plan to guide decisionson investment in further plans,projects or actions;

• Regional Assemblies and localauthorities who can use the planto inform spatial planningactivities and emergencyplanning;

• Internal Drainage Boards, watercompanies and other utilities tohelp plan their activities in thewider context of the catchment;

• transportation planners;

• land owners, farmers and landmanagers that manage andoperate land for agriculture,conservation and amenitypurposes;

• the public and businesses toenhance their understanding offlood risk and how it will bemanaged.

Figure 1. The relationship between CFMPs, delivery plans, projects and actions

CFMPs aim to promote moresustainable approaches tomanaging flood risk. The policiesidentified in the CFMP will bedelivered through a combination ofdifferent approaches. Together withour partners, we will implementthese approaches through a rangeof delivery plans, projects andactions.

The relationship between the CFMP,delivery plans, strategies, projectsand actions is shown in Figure 1.

Policy planning• CFMPs and Shoreline Management Plans.

• Action plans define requirement for deliveryplans, projects and actions.

Note: Some plans may not be led by us – we may identify theneed and encourage their development.

Policy delivery plans (see note)• Influence spatial planning to reduce risk and

restore floodplains.

• Prepare for and manage floods (including localFlood Warning plans).

• Managing assets.

• Water level management plans.

• Land management and habitat creation.

• Surface water management plans.

Projects and actions• Make sure our spending delivers the best

possible outcomes.

• Focus on risk based targets, for example numbersof households at risk.


The river catchments that make upthe East Devon CFMP are (from westto east) the Otter, Sid, Axe and Lim,each flowing directly into the sea.The Otter and Axe are the larger ofthese catchments. The Otter rises at300m Above Ordnance Datum (AOD)in the Blackdown Hills, while to theeast, the Axe rises at a lower altitudeof 175m AOD in the YeovilScarplands. Both of these rivers havesteeply sloping tributaries. The Sidand Lim are much smallercatchments with steep channelgradients from their source to thesea.

The East Devon CFMP covers an areaof some 750 square kilometres (300square miles). Annual rainfall rangesfrom more than 1,000mm (40in) inthe Blackdown Hills to less than800mm (32in) on the coast. TheEngland and Wales average is920mm (36in).

Catchment overview

The geology tends to becomeprogressively younger from west toeast. Older Permian, Triassic andJurassic layers are covered byyounger Cretaceous layers are stillpresent, forming plateaux at higherelevations, particularly in the Axeand Lim catchments.

The Permo-Triassic mudstones,sandstones and pebble beds lyingbeneath the Otter and SidCatchments lead to significantsurface run-off. The rivers respondrapidly to rainfall, and floods arecharacterized by a very rapid riseand fall in water levels, with highflood peaks.

Beneath the Axe and Limcatchments there are Triassic andJurassic calcareous clays andmudstones, and Cretaceousgreensand and chalk. These riversgenerally respond to rainfall, thoughthey respond slower than the otherEast devon rivers. The flood peaks ofthe River Axe reduce as they reach

wide floodplain, but the river isoften slow to recede in its lowerreaches. The greensand is importantin storing and slowly releasinggroundwater into the tributaries ofthe Axe, maintaining flow throughdry periods.

The catchment is known for itsvaluable visual landscape andincludes parts of the BlackdownHills, East Devon and Dorset Areas ofOutstanding Natural Beauty(AONBs). There are also four SpecialAreas of Conservation (SAC),oneSpecial Protection Area (SPA), 29Sites of Special Scientific Interest(SSSI), and 118 ScheduledMonuments.

Urban development is mainlyconcentrated in towns on the coast,notably Budleigh Salterton,Sidmouth, Seaton and Lyme Regis.Inland, with the exception ofHoniton, Axminster and Ottery StMary, the majority of land use isagricultural.


Map 1. Location and extent of the East Devon CFMP area

© Crown Copyright. Environment Agency 100026380.

Legend

East DevonCFMP

Urban areas

Main rivers

Railway

Motorway

0 3 6 9 12Kilometres

Cullompton

Sidmouth

Honiton

BudleighSalterton

OtterySt Mary

LymeRegis

Axminster

Beaminster

Crewkerne

Chard

N

Flooding at Colyford in January 2004


Current and future flood risk

Flood risk has two components: thechance (probability) of a particularflood and the impact (orconsequence) that the flood wouldhave if it happened. The probabilityof a flood relates to the likelihood ofa flood of that size occurring withinone year period. It is expressed as apercentage. For example, a 1% floodhas 1% chance or 0.01 probability ofoccurring in any one year, and a0.5% flood has a 0.5% chance or0.005 probability of occurring in any

one year. The assessment wasbased on the extent of our FloodZones (indicative flood extent with0.1%annual probability and 1%annual probability), models for themain urban areas at risk of floodingand records of historical floodevents. The models of the RiversOtter, Sid, Axe and Lim providesufficient details to investigatecurrent and future flood risk in thecatchment.

Overview of the current flood risk

Currently there are around 2,600residential and commercialproperties (5% of the total number inthe catchment) at risk from a 1%annual probability flood, not takinginto account current flood defences.Around 2,970 people are at risk inthe main communities of East Devon.

The East Devon catchment hasbiodiversity that is rich and diverse,and includes the internationallyimportant Sidmouth to West Bay,and River Axe SACs and 10 SSSIsthat are at risk of flooding.

118 Scheduled Monuments are atrisk of flooding in the catchment.

Road and rail links throughout thecatchment are at risk along withsome utility sites, schools and healthcentres.

What is at risk?

High flows in the River Sid, Sidmouth, November 1992

Table 2. Critical infrastructure at risk:

5 electricity substations, 1 wastewater treatment works, 2 railway lines, 9 A roads, and 5 B roads

Number of properties at risk Locations

100 to 500 Seaton, Sidmouth

50 to 100 Budleigh Salterton, East Budleigh

25 to 50 Newton Poppleford, Sidbury and Sidford, Honiton


Table 1. Locations of towns and villages with 25 or more properties at risk in a 1% annual probability river flood

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

35 - 50

51 - 100

101 - 250

251 - 350

351 - 500

East Devon CFMPMain rivers


Sidmouth

Budleigh Salterton

Honiton

Seaton

Axminster

NewtonPoppleford

N


How we currently manage the risk

Our activity is prioritised on a riskbasis. Our main activities include:

• Flood risk mapping – A major partof the programme is Flood ZoneImprovements and HazardMapping. This is focused onimproving the mapping at high-risk locations.

• Managing development – OurDevelopment Control teamsupports the planning process toensure applications have theappropriate flood riskassessments and follow PPS25(Planning Policy Statement 25 onDevelopment and Flood Risk).

• Flood warning – In some areasthere is currently no serviceprovided, in other areas such asSidbury, Sidford, Sidmouth,Otterton, Chard Junction,Axminster and Colyton there isless than 2.5 hours warningprovided. Registered propertiesreceive a direct message viaphone, email or fax. MajorIncident Plans have beendeveloped for Sidmouth, Sidbury,Sidford and Seaton.

• Flood defence schemes – We haveflood defence schemes toalleviate river flooding at Honiton,Ottery St Mary, Tipton St John, EastBudleigh, Sidmouth, Sidbury,Axminster, Colyton, Seaton andLyme Regis. In addition there are arange of local authority defencesin the catchment.

• Maintenance – We operate andmaintain flood defence banks andstructures, with local authoritiescarrying out further work.

The distribution of potential floodrisk from rivers and tides isillustrated in Map 2 for a flood with a1% annual probability (0.5% fortides) of occurring or beingexceeded.

The greatest concentration ofproperties at risk of flooding is atSeaton. Here some 450 propertiesare at risk from both river and tidalflooding. Sidmouth represents thenext greatest concentration, with320 properties at risk of flooding.

In addition to these locations, thereare risks of surface water flooding,which can be deep and fast flowing,across much of the catchment.However, further studies followingon from the CFMP are needed by usand our partners to quantify thispotential risk.

Where is the risk?


The impact of climate change and future flood risk

In the future, flooding will beinfluenced by climate change,changes in land use (for example,urban development) and rural landmanagement. In the East Devoncatchment, climate change isexpected to have the greatest impacton flood risk. The following futurescenario for climate change wasused in the CFMP:

• 20% increase in peak flow in allwatercourses. This will increasethe probability of large-scale floodevents,

• a total sea level rise of 950mm bythe year 2100. This will increasethe probability of tidal flooding.

Using river models we estimate thatby 2100, around 1,475 properties inthe key communities (Figure 2) maybe at risk from a 1% annualprobability flood, rising from thecurrent 1,220 properties. Flood riskfrom rivers increases mainly in thecommunities of Seaton, Sidmouthand Honiton.

The sensitivity testing undertakenshowed that urban developmentcould affect flood risk in Seaton,Sidmouth and Axminster. With therural nature of much of thecatchment we found that run-off fromagricultural land plays a part in floodrisk. An increase in run-off,

0

100

200

300

400

500

600

Current Future

Seaton Sidmouth Budleigh Ottery St Mary Lyme Regis East Budleigh Newton Sidbury Honiton Colyton Salterton and Uplyme Poppleford and Sidford

Num

ber o

f Pro

pert

ies

at F

lood

Ris

k

Figure 2. Current and future (2100) flood risk to property from a 1% annualprobability river flood, ignoring the presence of current flood defences

combined with a reduction in thetime it takes flows to peak, couldlead to flows increasing by up to 5%in the Axe and Otter catchments andup to 3% elsewhere in East Devon.

We have therefore consideredclimate change, urban developmentand land management in ourmodelling of future flood risk.


Approaches in each sub-area

We have divided the East Devon catchment into eightdistinct sub-areas which have similar physicalcharacteristics, sources of flooding and level of risk. We have identified the most appropriate approach tomanaging flood risk for each of the sub-areas andallocated one of six generic flood risk managementpolicies, shown in Table 3.

To select the most appropriate policy, the plan hasconsidered how social, economic and environmentalobjectives are affected by flood risk managementactivities under each policy option.

Map 3. East Devon sub-areas

Chard

Seaton

Martock

lish

Honiton

Exmouth

Sidmouth

Bridport

Axminster

Crewkerne

Ilminster

West Hill

Wellington

Lyme Regis

Cullompton

South Petherton

NewtonPoppleford

Ottery St Mary

Budleigh Salterton



N

LegendEast Devon CFMP

Sub-area

Upper Otter and Axe (Policy 6)

Axe and Otter Estuaries (Policy 6)

Budleigh Salterton (Policy 5)

Seaton (Policy 5)

Sidmouth and Lyme Regis (Policy 4)

Ottery St Mary (Policy 4)

Axminster and Honiton (Policy 3)

Rural Mid and Lower catchment (Policy 2)

1

2

3

4

5

6

7

8

9

Future direction for flood risk management

➜ Cattle marooned by floods from the River Axe near Bow Bridgein November 2005

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 defencesif we can use resources to reduce risk where there are more people at higher risk. We would therefore reviewthe 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 offlooding 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 reviewour approach to managing flood defences and other flood risk management actions, to ensure that we aremanaging 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 wemay 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, butwhere the risk of flooding is expected to significantly rise in the future. In this case we would need to do morein the future to contain what would otherwise be increasing risk. Taking further action to reduce risk will requirefurther appraisal to assess whether there are socially and environmentally sustainable, technically viable andeconomically 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 mostcompelling, for example where there are many people at high risk, or where changes in the environment havealready increased risk. Taking further action to reduce risk will require additional appraisal to assess whetherthere 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 inlocations 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 risklocally or more widely in a catchment by storing water or managing run-off. The policy has been applied toan area (where the potential to apply the policy exists), but would only be implemented in specific locationswithin the area, after more detailed appraisal and consultation.


Table 3. Policy options


Upper Otter and Axe

Sub-area 1

The issues in this sub-area

The Upper Otter and Axe sub-areaextends downstream as far as, butnot including, Honiton andAxminster.

The Blackdown Hills AONB covershalf of the area (the Otter, Yarty,Corry and Wolf catchments) and theDorset AONB a further quarter (themid to upper River Axe catchment).Apart from Chard, there are notowns in the area. However, thereare scattered villages and hamlets.

Approximately 15 properties and400 people are with 0.1% floodextent, dispersed across the sub-area. These properties may be atrisk from a 1% annual probabilityflood flood in the future.

Our key partners are:

East Devon District Council

Taunton Deane District Council

West Dorset District Council

South Somerset District Council

Devon County Council

Dorset County Council

Somerset County Council

There are no major flood defenceschemes and no flood warningservices for this area.

The River Axe SAC and SSSI areentirely within the 1% annualprobability flood extent and fourSSSIs are partially within it.However, flooding is one of thenatural river processes that areimportant in maintaining theconservation status of these sites.The Yarty, Otter, Wolf (Otter) andTale are at risk or probably at risk offailing the Water FrameworkDirective objectives as a result ofdiffuse pollution, and the area as awhole is classified as a NitrateVulnerable Zone.

The vision and preferred policy

Policy Option 6 - we will take actionwith others to store water ormanage run-off in locations thatprovide overall flood risk reductionor environmental benefits.

Increase in future flood risk willmainly be driven by climate changeand, to a lesser extent, by land useand land management changes.

By increasing floodplain storageand creating wetlands it is intendedto attenuate and retain floodwater,potentially reducing flood flows by

up to 35% for the urban areasdownstream. This presents anopportunity to enhance designatedsites by creating adjacent wetlandhabitats and linking existingwetland habitat. The economic andsocial implications are difficult toquantify but are unlikely to besignificant on the overall scale ofthe East Devon CFMP.

The policy could benefit theBlackdown Hills and Dorset AONBs.It is also likely to improve waterquality by reducing agriculturalrunoff, soil erosion and sedimentinput as a result of changing theway the land is used (increasedwetland habitat capable of holdingwater and slowing overland flows).This could contribute towardsachieving Water FrameworkDirective objectives.


Proposed actions to implement the preferred policy

• Develop, direct and deliver System Asset Management Plans that will reduce our level of maintenanceand to utilise the floodplains more effectively.

• With partners, identify locations, and implement measures for increased attenuation and retention offloodwater by floodplain storage, creating wetland habitat and restoring natural river banks. Workingwith our partners, ensure that areas identified for increased attenuation or water retention do notadversely impact upon designated features (including the historic environment). This action shouldcontribute to Water Framework Directive targets.

• Identify locations with the potential to improve land management and land use to benefit flood riskmanagement. In addition to reducing damage from river and ‘muddy’ land drainage flooding, thisaction should also improve water quality in the Otter, Axe, Yarty, Wolf and Tale rivers.

• We will ensure that development at Chard does not increase run-off or decrease water quality. Ensuringthat all new development incorporates Sustainable Drainage Systems (SuDS) will support this action.

Land use planners can support this policy by designating all floodplain and wetland areas as functionalfloodplain to support their attenuation and biodiversity roles.


Axe and Otter Estuaries

Sub-area 2


The Axe estuary, to the east ofSeaton, extends from the beach onthe coast upstream for threekilometres to the A3052 bridge atColyford. This does not includeAxmouth, Colyford, or Seaton(including those behind the SeatonMarshes flood defences).

The Axe estuary is influenced byboth fluvial and tidal flooding, buttowards Seaton the main source of



Natural England

Land Owners

National Farmers Union

Department for Environment, Foodand Rural Affairs (Defra) CatchmentSensitive Farming

flooding is from the sea.

The Otter estuary, to the east ofBudleigh Salterton, extends fromthe shingle beach on the coastupstream for two kilometres to thetidal limit at the confluence with theBudleigh Brook. The majority of theOtter estuary is influenced by bothfluvial and tidal flooding. An earthbank runs along its west side andprovides a standard of protection of0.7% annual probability. However,this only protects Budleigh SaltertonCricket Club and possibly a fewproperties on Granary Lane.

The Otter Estuary is designated aSSSI. Flooding is one of the naturalestuarine processes that areimportant in maintaining theestuary’s favourable conservationstatus.

There are no properties within thecurrent or future 1% annualprobability flood extent. Futureincreases in flood risk will be mainlydriven by climate change, both byincreasing flows and raising sealevels.


Policy Option 6 - we will take actionwith others to store water ormanage run-off in locations thatprovide overall flood risk reductionor environmental benefits.

The policy should not increase riskto any property.

The policy provides opportunities toreconnect the estuaries with thefloodplain and thereby createhabitat and wildlife corridors thatwould make a contribution towardsenhancing biodiversity.

Specific flood risk managementactions under the policy will notincrease flood risk to the Seatonregeneration area located at thesouthern end of Seaton Marshes.Defences to the marshes areconsidered as part of the Seatonsub-area.



• Develop, direct and deliver System Asset Management Plans that will reduce our level of maintenanceand will utilise the floodplains more effectively. This should also support improvements in the naturalenvironment.

• Investigate, with partners, locations along the Axe estuary where improving connection to thefloodplain could benefit biodiversity and reduce the risk of flooding to Seaton.

• Influence local agricultural practices on the Axe estuary to provide flood risk and biodiversity benefits.

• Investigate, with partners, locations along the Otter estuary where improving connection to thefloodplain could benefit biodiversity. This has the potential to both reduce damages in BudleighSalterton as well as support Biodiversity Action Plan species and habitats.

• Influence local agricultural practices on the Otter estuary to provide flood risk and biodiversity benefits.This should reduce damages to property and agricultural land whilst supporting the Otter Estuaryachieve the ‘Good’ target status of the Water Framework Directive.

Land use planners can support this policy by designating all floodplain and wetland areas as functionalfloodplain within their Local Development Framework. This will ensure that floodplains are retained forflood attenuation and green infrastructure benefits. Only water compatible uses should be permittedbehind the earth bank defences in the Budleigh Salterton area.

➜ Seaton Marshes flood in 1965


Budleigh Salterton

Sub-area 3


The area covers the catchment ofthe Budleigh Salterton Brookincluding Budleigh Salterton andKnowle.

Budleigh Salterton is located onhigher ground and there is littleflood risk from the River Otter. Mostof the flood risk is from theBudleigh Salterton Brook. Currently85 properties and 200 people inBudleigh Salterton are at risk fromthe 1% annual probability flood.The main source of future flood riskremains from the Budleigh SaltertonBrook with 230 people and 100properties potentially at risk from afuture 1% annual probability flood.Part of the Budleigh SaltertonConservation Area is also at risk ofdamage if the existing defences areovertopped.

There are no defences and nospecific flood warning service forthe Budleigh Salterton Brook.



South West Water

Natural England

Royal Society for the Protection of Birds (RSPB)


Policy Option 5 - we can generallytake further action to reduce floodrisk.

Future increases in flood risk willmainly be driven by climate changeas land use and managementchanges will have less of an impact.The chosen policy would protect allthe properties mentioned above,although they would still be at riskfrom more extreme events.

It is difficult to assess whether thispolicy complies with theenvironmental objectives as thenature of the impacts will dependon the details of any proposedactions. We consider that themajority of potential impacts couldbe reduced at the project designand implementation level. Thepolicy would also provideopportunities to improve landmanagement practices, which couldindirectly improve water quality tobenefit Atlantic salmon. The policyshould also reduce the risk offlooding within Budleigh SaltertonConservation Area.

Proposed actions to implement thepreferred policy

• Investigate ways of reducingflood risk on the BudleighSalterton Brook and implementfindings.

• Promote self-help opportunitiesto provide protection fromflooding in Budleigh Salterton.

• Ensure all new developmentsconform with ‘Planning PolicyStatement 25: Development andFlood Risk’.

• Investigate opportunities toenhance the water carryingcapacity of East DevonPebblebeds SAC, SPA and SSSI inconsultation with NaturalEngland, East Devon DistrictCouncil and the RSPB.

Land use planners should directnew development away fromfloodplain areas and seek reducedvulnerability of those developmentsremaining through change of use toless vulnerable types and increasedresistance and resilience measures.Sustainable Drainage Systemsshould be secured for alldevelopments, ideally strategicallyplanned and supported by policy.


➜ Recent flooding with Budleigh Salterton


Seaton

Sub-area 4


The area covers the town of Seatonand the village of Beer, which liestwo kilometres to the west ofSeaton.

Seaton is at risk of flooding fromcombined tidal and fluvial floodevents from the Axe estuary. Thetown is protected to a designstandard of 1% annual probabilityby the Seaton Marshes flooddefence scheme, although a recentinvestigation has suggested that theactual standard may be as low as5% (1 in 20 years). Approximately5% of the Seaton Conservation Areais at risk if the existing defences areovertopped.



East Devon AONB

South West Water

Natural England

The main source of flooding is fromthe sea. A tidal flood warning serviceand a Major Incident Plan is in placefor Seaton for this risk. There is noflood warning in Seaton for floodflows in the River Axe.

There are 450 properties at risk froma 1% annual probability flood event.

Future increases in flood risk willmainly be driven by climate change,but land use and managementchanges will also have an impact.The main source of future flood riskin Seaton will continue to be tidalflooding from the Axe estuary, with500 properties at risk from a future1% annual probability flood event..Many of these people live in areas ofhigh social vulnerability.

In Beer surface water floodingcauses a significant problem. This isdue to run-off from agricultural landin the small and steep catchment. Athird of Beer’s Conservation Area isat risk of damage in a 1% flood.


Policy Option 5 - we can generallytake further action to reduce floodrisk.

The policy will help address risks atBeer, for example by seeking toinfluence land managementchanges in the Beer catchment.

The policy would also ensure thatthe sewage treatment works atSeaton continue to be protectedfrom flooding, ensuring that waterquality is not compromised.

Although there is some potential foradverse impacts on Natura 2000sites, these will be assessed andmitigated to ensure that only neutralor positive effects arise. Similarly,other adverse environmentalimpacts could be reduced oravoided at the projectdesign/implementation level.



• Develop, direct and deliver System Asset Management Plans to help reduce flood risk.

• Quantify the benefit of flood risk management measures in the Axe estuary, and assess the impacts onSeaton and the Regeneration Area. This should ensure that there is no net negative impact on thenatural environment.

• Improve the flood warning service for fluvial and tidal flooding and promote self-help opportunities toprovide protection from flooding in Seaton.

• Improve Flood Zone maps in Seaton.

• Ensure all new developments conform with ‘Planning Policy Statement 25: Development and FloodRisk’. In particular, Sustainable Drainage Systems should be incorporated to restrict surface water run-off. It should also be noted that the policy has been adopted to reduce future risks to existingresidential and commercial property - it is not to enable new development to take place in areas at riskof flooding.

• Investigate ways to move people and critical infrastructure out of risk areas.

• Develop a land management strategy for Beer to reduce the number of properties at risk, damages fromflooding and where possible contribute to an improvement in water quality.

➜ A resident of Beer cleans up after a muddy flood in her home in August 2004


Sidmouth and Lyme Regis

Sub-area 5


The Sidmouth area extends for fivekilometres inland to include Sidfordand Sidbury. Currently in Sidmouth,Sidbury and Sidford, 350 propertiesare within the 1% annual probabilityflood extent. This number isexpected to rise to 400 propertieswithin the future 1% annualprobability flood extent.

Sidmouth and Sidbury flooddefences have a standard ofprotection of 3% to the left bank and1.7% to the right bank of the RiverSid. Due to the nature of the Sidcatchment there is little timebetween the rainfall and the floodpeak. Flood warning times inSidmouth are half an hour or lessalthough the flood hazard isgenerally low.

The Lyme Regis area extends,approximately two kilometres inlandto Uplyme. The upper reaches of theRiver Lim are located within the EastDevon AONB and lower reacheswithin the Dorset AONB.



South West Water

Overall, 60 properties are within the1% annual probability flood extent.This number is expected to rise to90 properties within the future 1%annual probability flood extent.However, Lyme Regis and Uplymeare protected from the River Lim to a1% annual probability standard ofprotection. There is currently noflood warning service in Lyme Regisas due to the nature of the Limcatchment there is little timebetween the rainfall and the floodpeak. Flooding is likely to be bothdeep and fast, and is categorised asa significant or extreme hazard forapproximately 80 people.


Policy Option 4 - We are alreadymanaging the flood risk effectively,but we may need to take furtheractions to keep pace with climatechange.

Future increases in flood risk willmainly be driven by climate change.Land use management changes arelikely to have less of an impact.Slightly more properties will be atrisk, but the flood hazard remainsgenerally low. This will substantiallyreduce the average annualdamages, and will control the floodhazard to people within Lyme Regis.

Potential adverse environmentalimpacts could be reduced at theproject design and implementationlevel. Therefore, we consider thispolicy can be environmentallyacceptable.

Sustainable Drainage Systemsshould be implemented in problemareas, these could also helpachieve Water Framework Directiveobjectives for the River Sid which isfailing Water Framework Directiveobjectives for diffuse pollution.



• Develop, direct and deliver System Asset Management Plans to sustain the current scale of flood risk.

• We will further investigate the flood risk in Sidmouth and Lyme Regis, particularly for extreme floods,and making use of our Rapid Response Catchments Project. We will influence South West Water toimprove capacity of sewers. This is in order both to reduce both the number of flood incidents, and toimprove water quality.

• We will develop a strategy for managing weirs to improve flood risk management and provideenvironmental benefits.

• Develop our programme for Flood Hazard Mapping to determine direction and velocity of flow.

• We will investigate ways of improving flood warning in Sidmouth and Lyme Regis, and promote self-help opportunities to provide protection from flooding in specific locations.

• Ensure all new developments conform with ‘Planning Policy Statement 25: Development and FloodRisk’. We will encourage the planning authority to open up floodplains and culverts throughredevelopment.

• Investigate ways in which people can be moved out of risk areas, particularly as poor housing stockdeteriorates over the longer term. Investigate also if critical infrastructure can be moved out of riskareas.

➜ Lyme Regis has a long history of floods: the River Lim in June 1890


Ottery St Mary

Sub-area 6


The area covers Ottery St Mary andall of the Furze Brook catchment tothe east of the town.

Currently 75 properties, 180 peopleand 20% of Ottery St Mary’sConservation Area are within the1% annual probability flood extent. St Saviour and Cadhay Bridges(Grade II listed structures) are likelyto be exposed to flooding. Thisnumber is expected to rise to 85properties within the future 1%annual probability flood extent.

Ottery St Mary is protected from theOtter by flood banks and walls thatprovide a standard of protection of1% annual probability. Defences onthe Furze Brook to the samestandard consist of culverts andchannel improvements.

There is a flood warning service forthe River Otter in Ottery St Mary witha warning time of over five hours.However, there is no flood warningservice available for the FurzeBrook.



South West Water

Natural England


Policy Option 4 - we are alreadymanaging the flood risk effectivelybut we may need to take furtheractions to keep pace with climatechange.

Increases in flood risk will mainly bedriven by climate change. Land useand management changes withinthe Furze Brook catchment may alsoincrease risk. As a result annualaverage damages in Ottery St Marycould double in the future.

The policy has been selected tosustain the current 1% standard ofprotection of defences into thefuture.

The opportunity to influence landmanagement improvements is likelyto enhance biodiversity andpositively contribute towards thecharacter of East Devon AONB.

Proposed actions to implement thepreferred policy

• Develop, direct and deliverSystem Asset Management Plansto sustain the current scale offlood risk.

• Identify and develop specificflood risk management measuresthat will sustain the current scaleof flood risk in the future.

• Improve Flood Zone maps inOttery St Mary.

• Promote self-help opportunitiesto provide protection fromflooding in Ottery St Mary.

• Ensure all new developmentsconform with ‘Planning PolicyStatement 25: Development andFlood Risk’. In particularSustainable Drainage Systemsshould be incorporated intodevelopment to restrict surfacewater run-off.

• Investigate whether the firestation, and other criticalinfrastructure currently at risk,can be relocated over the longerterm.

• Influence South West Water toimprove the capacity ofcombined sewers in Ottery StMary to reduce damages andimprove water quality.

• Carry out a study in thecatchments of the Furze Brook,working with the agriculturalindustry, to try and change landmanagement practices to reducethe direct run-off from agriculturalland.


Axminster and Honiton


The Axminster area includes boththe town and the floodplain of theRiver Axe. Although the majority ofAxminster is on higher ground, someproperties and industrial units alongthe north west side of the town nearStoney Bridge are located within thefloodplain of the River Axe. For the1% annual probability flood, 20properties and 45 people are at risk.In the future 1% annual probabilityflood the same number of propertiesare expected to be at risk.Approximately three quarters ofthese are residential properties withthe remainder being commercial.

Currently flood warning times areless than two hours from the RiverAxe in Axminster. Flood defencesprovide some protection toproperties at risk. An earthembankment on the right bankprovides a 1.7% annual probabilitystandard of protection. The railwayembankment and stone revetmentson the left bank provide a 1% annualprobability standard of protection.



South West Water

The Honiton area covers the GlenBrook and Gissage Streamcatchments that flow north westthrough Honiton into the River Otter.

Defences in Honiton consist ofculverts and channel improvements.These provide an overall standard ofprotection of 1% annual probabilityto 35 properties and 85 people Ifdefences were not present 140properties would be within thefuture 1% flood extent. There is noflood warning service for the Glenand Gissage Streams.


Policy Option 3 - we are generallymanaging existing flood riskeffectively.

Increase in flood risk will mainly bedriven by climate change. Althoughfor Honiton, the Gissage Streamcatchment land use andmanagement changes may alsoincrease risk. We believe that thecurrent scale of flood riskmanagement is sufficient andmanaged to an appropriate level.We consider that future increases inrisk will be acceptable.

For Honiton the current standard ofprotection of defences maydeteriorate to approximately 3% in

the future but will still provideprotection against more frequentflood events. In the context of theEast Devon CFMP as a whole theserisks are relatively low.

Honiton is likely to expand in thefuture and land use planners mustensure that this does not increaserisks further. Axminster has alsobeen earmarked for futuredevelopment. The local planningauthority will need to determine asustainable policy approach todevelopment in this area in linewith PPS25 and in particular thesequential approach to landallocations. Where feasible land useplanners should look to reduceflood risks overall.

Sub-area 7



• Develop, direct and deliver System Asset Management Plans to sustain the current scale of flood risk.

• Investigate ways of improving flood warning in Honiton, and in Axminster where our target would be increasewarning times to over two hours.

• Improve Flood Zone maps in Honiton.

• Promote self-help opportunities to provide protection from flooding including at Honiton.

• Ensure all new developments conform with ‘Planning Policy Statement 25: Development and Flood Risk’. Inparticular Sustainable Drainage Systems should be incorporated into development to restrict surface water run-off. Land use planners should also seek to reduce the vulnerability of property at risk and behind defences. Thiscan be achieved by changing uses to less vulnerable types; by incorporating flood resilience and resistancemeasures, and to ensure suitable warning and evacuation procedures are provided.

• Carry out a study to investigate the risk of flooding to the Wilmington water treatment works.

➜ Clapper Lane Bridge: a tree is carried down by flood waters and needs to be removed


Rural Mid and Lower Catchment

Sub-area 8


This large area covers the Ottercatchment below Honiton and theAxe catchment below Axminster. Italso covers the Sid and Limcatchments, excluding the urbanareas around Sidmouth and LymeRegis.

The area is mainly rural but doescontain a number of settlements,notably East Budleigh, Otterton,Colaton Raleigh, Newton Poppleford,Tipton St John, Colyton and Colyford.Much of the area is designatedAONB.

Approximately 130 properties and290 people are at risk from the 1%annual probability flood, and 200properties and 450 people from themore extreme 0.1 % flood. For thefuture 1% annual probability floodwe expect the number of properties



Natural England

English Heritage

National Farmers Union

Defra Catchment Sensitive Farming

to increase to around 200 at risk.

A flood warning service for urbanareas in the Otter catchment giveswarning times of more than twohours, so improvements here arenot a priority. However, floodwarning times in the urban areas ofthe Axe catchment could beincreased. For example, the warningtime for Colyton is less than 30minutes.

There are a range of flood defencesacross the area. In Tipton St Johndefences provide a 3% annualprobability standard of protectionfrom the River Otter. In NewtonPoppleford a 2% standard isachieved. In East Budleigh defencesprovide a 3% standard of protectionfrom the Budleigh Brook. In Colytona 1% standard of protection and inColyford a 2.5% standard ofprotection is provided from the RiverColy.

The area is within a NitrateVulnerable Zone and the rivers areall at risk, or probably at risk, offailing the Water FrameworkDirective objectives as a result ofdiffuse pollution. Flood riskmanagement activities andassociated land use managementshould contribute to reducing thisproblem.


Policy Option 2 - we can generallyreduce existing flood riskeffectively.

Future increases in flood risk willmainly be driven by climate change,but land use and managementchanges will also have an effect.

Generally, spending on flood riskmanagement activities will bereduced, allowing for more naturalriver processes, creation of wetlandhabitats, and the reconnection ofrivers with their floodplains.Localised defence measures wouldcontinue to be maintained insettlements at risk such as Tipton StJohn and Newton Poppleford.



• Develop, direct and deliver System Asset Management Plans that will reduce our level of maintenance.

• Monitor the scale of flood risk, in particular in Colyton, Newton Poppleford and Tipton St John, and assessflood risk management measures.

• Identify locations with the potential to improve land management and land use to benefit flood riskmanagement. This is intended both to reduce the consequence of flooding and also contribute towardsWater Framework directive targets.

• Consider ways of reconnecting the River Otter and River Axe to their floodplains to utilise flood storageand reduce risk to people. With our partners, ensure that areas identified for increased attenuation orwater retention do not adversely impact upon designated features (including the historic environment).

➜ Floods through Otterton in February 1969


Map of CFMP policies

Map of the policies in the East Devon catchment

1 Upper Otter and Axe

2 Axe and Otter Estuaries

3 Budleigh Salterton

4 Seaton

5 Sidmouth and Lyme Regis

6 Ottery St Mary

7 Axminster and Honiton

8 Rural Mid and Lower Catchment

The sub-areas


Legend

Main rivers

Urban areas

Preferred approach

Policy 1

Policy 2

Policy 3

Policy 4

Policy 5

Policy 6

East DevonCFMP

Wellington

Bridport

Chard

Cullompton

Honiton

Sidmouth

Axminster

Ottery St Mary

Beaminster

Crewkerne


Seaton

Budleigh Salterton

LymeRegis

1

2

2

3

45

5

6

778

N

GESW0612BWSC-E-E

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