Coastal flood risk management strategy, Pegwell Bay to Kingsdown

Published by:Environment Agency in partnership withDover District CouncilEnvironment AgencyOrchard HouseEndeavour ParkLondon RoadAddingtonWest MallingKentME19 5SHwww.environment-agency.gov.uk/yourenv/consultations/current_consultations/© Environment Agency

introductionThe Environment Agency andDover District Council areworking together to develop astrategy to manage coastalflooding and erosion betweenPegwell Bay and the MoD RifleRange at Oldstairs Bay. Thestrategy will also look at tidalflooding in the River Stourdownstream of Fordwich. Theresult will be the Pegwell Bay toKingsdown coastal strategy.This new strategy will developthe flood management policiesset out in the Isle of Grain toSouth Foreland shorelinemanagement plan and theRiver Stour catchment floodmanagement plan.With the climate changing, sealevels rising and increasedfrequency and intensity ofstorms, our existing coastaldefences are under increasingthreat from the elements. Thisconsultation document sets outthe options for the strategy tomanage the area’s coastal andtidal river defences over thenext 100 years.The Environment Agency andDover District Council havepowers to construct flooddefences for the protection ofpeople and property wherethese are economically justifiedand government funds areavailable. The amount offunding available from centralgovernment is limited and thereis strong competition for thesefunds from around the country.The Environment Agency alsohas a legal obligation to protectendangered habitats such asinter-tidal salt marsh andmudflats that form part of anetwork of internationallydesignated sites. These areconsidered to be at risk fromrising sea levels and wheresections are lost compensatoryareas will have to be provided.This document introduces thekey issues we need to addressin the strategy and outlines theleading options. It has beenprepared as part of the publicconsultation on the strategyand you are invited tocomment. Details on how tocontact us are provided on theinside back cover.Environment Agency Pegwell Bay to Kingsdown coastal strategy 3

the Pegwell Bay toKingsdown coastlineThe frontage of the Pegwell Bayto Kingsdown coastline has twodistinct characters. To thenorth of Sandwich Bay Estatethe coast is characterised by anextensive dune system behinda sand and shingle beach. Thedunes narrow towards Dealwith low-lying agricultural landbehind. Most of the dunes areincorporated into three golfcourses, which attract a largenumber of visitors to the area.The residential area of northDeal is also low-lying.To the south of Deal the landbegins to rise to meet the cliffsat the southern end of thestrategy frontage. This stretch ischaracterised by residentialareas, with agricultural landfurther back. The shinglebeach is reinforced with formaldefences towards the south.The area’s close proximity tothe Continent has led to a richhistory in trade. Its historicbuildings and the Cinque Portof Sandwich has resulted in thearea becoming a populardestination for visitors, withnumerous facilities andrecreational activities both landand water based.The River Stour is tidal up toFordwich, approximately 17miles upstream. With itstributaries it drains aconsiderable part of the Kentcountryside, flowing throughthe urban areas of Canterburyand Sandwich.The area supports large areasof coastal habitats designatedwithin the Natura 2000network. These include sitesdesignated as SpecialProtection Areas (SPA), SpecialAreas of Conservation (SAC),Sites of Special ScientificInterest (SSSI) and NationalNature Reserves (NNR).4 Environment Agency Pegwell Bay to Kingsdown coastal strategy

strategic options for managingthe strategy areaThe coastal and river frontageswithin the strategy area havebeen divided into nine reachesreflecting the varying nature ofthe frontage and the specificissues affecting each reach.Reach 1: Cliffs End toStonar CutGenerally low lying coast andriver frontage sheltered fromwave energy by the extensiveinter-tidal mudflat area inSandwich Bay.Reach 2: Shell Ness toSandwich Bay EstateSand dunes fronted by a widesandy foreshore, which narrowstowards the southern end ofthis section. Shingle depositsoverlay the sand beach alongthe northern half of this unit.Reach 3: Sandwich Bay EstateThis residential area is locatedimmediately behind a concretebased revetment (bank)and thenatural shingle beach.Reach 4: Sandwich Bay Estateto Deal CastleBetween Sandwich Bay Estateand Deal flood protection isprovided by a colliery shaleembankment. Along the Dealfrontage this is replaced by aseawall and timber groynes. Ashingle beach providesadditional protection along thewhole of this frontage.Reach 5: Deal Castle toWalmer CastleThis frontage is characterisedby its wide and openshingle beach.Reach 6: Walmer Castle,Kingsdown and Oldstairs BayThe wide shingle beach atWalmer gradually reduces insize towards the south. Aconcrete seawall, timbergroynes and the shingle beachprotect Kingsdown. A groynedshingle beach and rockrevetment provide erosionprotection to the exposed areaof Oldstairs Bay.Reach 7: MoD Rifle RangeThe former Rifle Range at thefoot of cliffs is protected by aconcrete seawall.Reach 8: Sandwich andStonar LoopRiver frontage mainly protectedby earth embankments, withflood walls through Sandwich.Reach 9: Stour ValleyRiver frontage predominantlyprotected by earthembankments with floodplainson both banks.Strategic optionsThe strategy will set out how weneed to manage coastal andtidal flood and erosion risk forthe next 100 years. To do thiswe will consider for each of thenine reaches a range of optionsdescribed in the table below.Coastal strategyDo nothing – no furthermaintenance or repair workis undertakenDo minimum – emergencyrepairs undertaken asrequiredMaintain – maintaining theexisting defences in theircurrent formSustain – defences areraised and strengthened tosustain the current standardof protectionImprove – defences areimproved to increase thestandard of protectionManaged realignment –moving defences inland in acontrolled way to a moresustainable positionEnvironment Agency Pegwell Bay to Kingsdown coastal strategy 5

what do these options mean for me?Nature can affect the coast and riverbanks in different ways. The level ofimpact depends on the current and future flooding and erosion risks in thedifferent reaches of the strategy. The condition of the existing flood defencesis also a factor in the impacts that can be expected as some are in bettercondition than others.The following identifies the impact on those reaches at risk of flooding if noaction is taken. Reaches 2, 5, 7 and 9 require do nothing or do minimum asdescribed later.Reach 1: Cliffs End to Stonar CutIf nothing is done, 14 propertieswould be flooded annually andtherefore lost by 2107. A further24 residential and commercialproperties would also beaffected by flooding, althoughthe damage to individualproperties would vary.It is also likely to lead toflooding of large stretches ofthe low-lying land of theWantsum Channel, while flooddamage to the A256 is alsoincreasingly likely.Reach 3: Sandwich Bay EstateAlthough the current defencesprovide sufficient protection tothe properties in Sandwich BayEstate now, if nothing is doneduring the next 100 years 38properties will be lost due toannual flooding by 2107. Afurther 54 properties would beaffected by flooding.Reach 4: Sandwich Bay Estateto Deal CastleAlmost 1,300 residential andcommercial properties arecurrently at risk of floodingduring an extreme tidal event(1 in 100 chance of occurringeach year). This would rise tomore than 4,000 by 2107 if noaction was taken, with many ofthose lost permanently.Along this reach the CinquePorts golf course is also likely tosuffer significant damage, whilethe promenade and Pier at Dealwould also become increasinglyvulnerable to flood damage.Reach 6: Walmer, Kingsdownand Oldstairs BayIn this reach the main problemis erosion of the coastline,which will move landward if nomeasures are taken to stop thisprocess. There would be asteady loss of property in thisreach and it is expected thatapproximately 177 propertieswould be lost by 2107.Reach 8: Sandwich and StonarLoopIn the current situation someflooding already occursoccasionally, most markedly atSandwich Quay. To date, thishas not resulted in the loss ofproperties but there has beensome flood damage to propertyin Sandwich in the past – mostnotably in 1953 and 1983.Almost 500 properties arecurrently at risk of floodingduring a tidal event with a 1 in 20chance of occurring each year.If no action was taken, by 2107some 1,400 properties would beaffected by flooding to varyingdegrees during significant tidalevents, with nearly 600properties affected so badlythat they would be lost.6 Environment Agency Pegwell Bay to Kingsdown coastal strategy

shortlisted optionsFor each of the nine reaches a number of appropriate options were shortlistedfor further analysis. To determine the preferred option each of thereaches has been considered in terms of:• flood and erosion risk to people and property;• climate change and predicted sea level rise;• cost of the option and value of protected assets;• impact on the natural environment.The following paragraphs outline the characteristicsof all nine reaches together with the short-listedoptions for the relevant reach. The leading optionfor each reach has been highlighted in blue.Pegwell Bay, Reach 1Reach 1: Cliffs End to Stonar CutThe only reach combiningcoastal and river frontages,the reach between Cliffs Endand the Stonar Cut comprisesthe left bank of the RiverStour downstream of theStonar Cut and the coastalfrontage of Pegwell Bay.Pegwell Bay Country Park hasa small embankment at itsperimeter boundary while theA256 provides furtherprotection to the land behind.There are no formal flooddefence structures along theriver frontage as the groundlevel north of RichboroughPort provides the protectionagainst flooding, while atRichborough Port itself, floodprotection is provided by theland behind the quayside.The inter-tidal mudflats onthe coast and the rivercorridor itself are ofinternational environmentalvalue.The Stonelees Golf Club islocated behind the A256.Strategic optionDo nothingDo minimumSustainImproveActionsNo further work will be undertaken on the existing defencesRepair A256 road and rock revetment as and when damage occursThe existing defences currently offer sufficient protection. To sustain thisprotection into the future the defences will need to be improved in about 50years, with a combination of walls and embankments adjacent to the A256Works are undertaken now to increase protection, with a combination of wallsand embankments adjacent to the A256Sustain has been selected because the existing level of protection is sufficient, although workswill be required in the future to allow for sea level rise. This option provides the best economicoption and will not have significant impact on the natural environment.Environment Agency Pegwell Bay to Kingsdown coastal strategy 7

Reach 2: Shell Ness to Sandwich Bay EstateThis reach comprises thecoastline between Shell Nessand Sandwich Bay Estate. It ischaracterised by a sandybeach backed by an extensivedune system. The groundlevels of the dune systemprovide protection fromflooding for the land behindthe dunes. The frontage has alarge area of inter-tidalmudflats on the seawardside, which narrows towardsthe southern end of the reach.The entire frontage forms partof an important internationalnature conservation area andthere is an RSPB naturereserve approximatelyhalfway along the reach. Thearea contains no residentialsettlements, but there are twomajor golf courses. Two longdistancefootpaths run alongthe length of the reachproviding access to the frontagefrom the centre of Sandwich.Strategic optionDo nothingDo minimumActionsNo further work will be undertaken on the existing defencesReactive maintenance onlyDo nothing has been selected because of the existing high level of protection provided by thebeach and works to the dunes would have a negative impact on the designated sites. In the eventof a major breach in the dune system during an extreme storm there is a possibility of emergencyrepairs, including re-profiling of dunes and breach repairs. Under the ‘do nothing’ option the riskof flooding is acceptably low.Reach 3: Sandwich Bay EstateThe reach comprises ashingle beach backed by aconcrete revetment.The beach and defences inthis reach protect SandwichBay Estate, a residentialsettlement. To the southernend of the reach there is asailing club, which launchesits vessels directly fromthe beach.The land immediately to thenorth and south of SandwichBay Estate is subject tointernational environmentaldesignations, as are thebeach and foreshore.Strategic optionDo nothingDo minimumMaintainSustainActionsNo further work will be undertaken on the existing defencesExisting revetment is patch repaired when damage occursNo work on defences other than local maintenance in first 50 years.Replacement of the existing revetment in 2057No work on defences in first 50 years. Replacement of the existing revetmentin 2057 and beach nourishment undertaken to sustain the level of protectionMaintain has been selected because the existing level of protection is sufficient, but works will berequired in the future to ensure the integrity of the existing revetment. This option provides the besteconomic option and will not have significant impacts on the natural environment.8 Environment Agency Pegwell Bay to Kingsdown coastal strategy

Reach 4: Sandwich Bay Estate toDeal CastleNorth of Sandown Castle thefrontage consists of beachesbacked by a colliery shaleembankment and a narrowdune system. The beach anddunes are of importantinternational environmentalvalue. Further inland parts ofthe Lydden Valley are alsosubject to internationalenvironmental designations.A golf course is situatedamong the dunes and a longdistancefootpath follows thecoastline. The Lydden Valleycontains a dense network ofstreams and ditches and iscrossed by a mainline railway.From Sandown Castle to DealCastle the coast is protectedby a shingle beach withtimber groynes and aconcrete sea wall. The flooddefences protect a large areaof Deal from flooding.Coastal frontage north of Deal, Reach 4Both Deal and SandownCastles are scheduledmonuments, while the towncontains several listedbuildings and conservationareas.Strategic optionDo nothingDo minimumMaintainImprove 1Improve 2Improve 3Improve 4ActionsNo further work will be undertaken on the existing defencesNo pro-active maintenance, but breaches or failures in the existing defenceswill be repaired if they occurThe existing defences will be actively maintained to reduce the risk ofbreaching or failure and keep them in a similar condition as they are todayBeach management to increase the shingle volume of the beach throughout thereach. The existing timber groynes will remain in place until the end of theirremaining life. A rock revetment will be provided just north of Sandown Castleto protect the shale embankment. A low wave wall will be constructed in Dealto reduce the risk of waves overtopping onto the roadTimber groyne replacement and beach nourishment to increase the shinglevolume of the beach. Rock revetment will be provided just north of SandownCastle to protect the shale embankment. A wave wall will be constructed in DealRock groynes would replace the existing timber groynes with beachnourishment to increase the shingle volume of the beach. Rock revetment willbe provided just north of Sandown Castle to protect the shale embankment.A wave wall will be constructed in DealThree large rock headlands would replace the existing timber groynes withbeach nourishment to increase the shingle volume of the beach. Rockrevetment will be provided just north of Sandown Castle to protect the shaleembankment. A wave wall will be constructed in DealEnvironment Agency Pegwell Bay to Kingsdown coastal strategy 9

erosion risk andtidal flood risk10 Environment Agency Pegwell Bay to Kingsdown coastal strategy

Environment Agency Pegwell Bay to Kingsdown coastal strategy 11

Reach 4 ...continuedImprove 1 has been selectedbecause the existing level ofprotection just north ofSandown Castle is too low,and north Deal would beexposed to flooding if theembankment was damaged.In addition, a wave wall inDeal would mitigate againstfuture sea level rise, whichwould otherwise lead toincreasing flood damage inDeal by waves overtoppingthe seawall. The beachmanagement option wouldprovide a wider moreextensive shingle beach toprotect Deal, and is theleading economic solution.Deal seafront, Reach 4Reach 5: Deal Castle to Walmer CastleThe frontage between DealCastle and Walmer Castleconsists of a shingle beachwith no formal flood defences.The beach widens from 50m inthe north to 100m towards thesouthern end of the reach,providing sufficient flooddefence for Walmer and thesouth of Deal. There are twoscheduled monuments locatedimmediately behind the beach,with Walmer Castle set into ahistoric park and garden.A long-distance footpath runsalong the entire length of thefrontage.Strategic optionDo nothingDo minimumActionsNo further work will be undertaken on the existing defencesNo active maintenance will be undertaken. However, some minor beachmanagement work could be undertaken if these are beneficial to coastalprocesses for neighbouring frontagesDo minimum has been selected because the existing level of protection provided by the beach ishigh, and is expected to remain so with future sea level rise. No properties would be at risk if the ‘dominimum' option is adopted.12 Environment Agency Pegwell Bay to Kingsdown coastal strategy

Reach 6: Walmer Castle, Kingsdown and Oldstairs BayThis reach comprises thecoastal frontage betweenWalmer Castle and the MoDRifle Range. The frontageconsists of beaches with a seawall at Kingsdown,interspersed by timbergroynes.Behind the coastal defencesthe land rises relatively steeplyand consists predominantly oflow to medium densityresidential development, withagricultural land furtherinland.A long-distance footpath runsalong the northern frontagewithin the reach.Strategic optionDo nothingDo minimumMaintainSustainImproveActionsNo further work will be undertaken on the existing defencesNo pro-active maintenance, but breaches or failures in the existing defenceswill be repaired if they occurBeach recycling combined with replacement of existing timber groynes at the endof their remaining life (about 10 years). Supplemented by shingle when requiredSimilar to maintain option, but repairs to timber groynes will start early in thestrategy and additional shingle will be brought onto the beachA range of improvement options have been considered, including constructionof rock headlands, replacement of existing groynes and beach with rockrevetment, construction of rock groynes and the refurbishment and upgrade ofthe existing seawall at KingsdownMaintain has been selected since this option would prevent erosion and loss of property, and is themost cost-effective and environmentally acceptable solution.Reach 7: MoD Rifle RangeThe MoD Rifle Range consistsof an elevated plateau of fillmaterial in front of chalk cliffs,protected by a concreteseawall.The site and cliffs are subjectStrategic optionDo nothingDo minimumManagedrealignmentActionsto national environmentaldesignations and a footpathruns along the base of the cliffs.There is some uncertaintyabout the nature of the fillmaterial for release into theNo further work will be undertaken on the existing defencescoastal system. The sea wallhas collapsed at one sectionallowing some fill material toseep out.The site is owned by the MoD.Repair of failed sections of the seawall and reactive repairs to further failures.These repairs are likely to consist of steel sheet piled retaining walls or rockarmour infillFollowing a detailed investigation of fill material for contamination andappropriate remediation work, the existing seawall would be removed or left tocollapse allowing the site to return to natural processesManaged realignment has been selected. This would provide the maximum environmental benefit,restoring the coastline towards a more natural process, which would benefit the beaches to thenorth. This option is dependent on further analysis of the site and the availability of funding andintentions of the land owner, who will be responsible for implementation of this option.Environment Agency Pegwell Bay to Kingsdown coastal strategy 13

Reach 8: Sandwich and Stonar LoopThe Sandwich and Stonar reachcomprises the downstreamsection of the tidal River Stouras it loops through the historictown of Sandwich.Industrial activity dominatesland inside the loop, withPfizer owning the majority.The area east of the river loopis predominantly high gradeagricultural land, with largesections subject toenvironmental designationssuch as SSSI, SAC, Ramsarsite and SPA.Sandwich is rich in culturalheritage, including scheduledmonuments, listed buildingsand conservation areas.Further upstream on the rightbank Richborough Castle isalso a scheduled monument.Long-distance footpaths arelocated along the banks ofthe river.The A256 crosses the RiverStour west of Sandwich andruns through the centre of theStonar Loop to Thanet and theDeal to Canterbury railwayline runs through Sandwichand follows the westernsection of the river.Strategic optionDo nothingDo minimumSustainImprove 1Improve 2Improve 3ActionsNo further work will be undertaken on the existing defencesNo pro-active maintenance, but breaches or failures in the existing defenceswill be repaired if they occurTo continue the present standard of protection, the existing ‘on-line’ defences(such as the banks of the River Stour) will be raised to allow for projected sealevel rises. They will need raising again in 50 years to keep pace with thecontinued sea level rises‘On-line’ defences – raising defences along the River Stour to increase thestandard of protection. As under the ‘sustain’ option these defences will haveto be raised again in 50 years to keep pace with sea level risesTidal storage and ‘on-line’ defences – Construction of a tidal storage facility inthe Broad Salts area. This includes the construction of a spillway,embankments and a drainage facility. The ‘on-line’ defences will also need tobe raised, but not as much as if ‘on-line’ defences were the only protectionTidal barrier and ‘on-line’ defences – A tidal barrier would be constructed onthe River Stour near Richborough Port. The existing embankments on theeastern bank of the River Stour would be raised and strengthened andextended to the coast north of Sandwich Bay Estate. The ‘on-line’ defences willalso need to be raised, but not as much as for ‘on-line’ defences onlyAll improve options have been evaluated against economic andenvironmental criteria. Improve 2 has been selected becausethe existing level of protection is too low, and significant areasof Sandwich and all of Stonar Loop are at risk of flooding. Thetidal storage option keeps the raising of the ‘on-line’ defencesthrough Sandwich to a minimum. It also provides potential for a230 hectares wetland/nature reserve to be developed,enhancing the existing network of designated sites andproviding additional recreation opportunities. It is the leadingeconomic and environmental solution.Sandwich, Reach 814 Environment Agency Pegwell Bay to Kingsdown coastal strategy

Broad Salts, Reach 8Environment Agency Pegwell Bay to Kingsdown coastal strategy 15

Reach 9: Stour ValleyAlong the River Stour floodprotection is predominantlyprovided by earthembankments, apart from thefrontage immediately north ofRichborough Castle whereground levels provideadequate protection againsttidal flooding.The land on both banks isconsidered to be good to verygood grade agricultural land.Flooding in this reach isdominated by fluvial processes.Therefore the long-termstrategic management of thisarea will be determined in theforthcoming Lower Stour Riverstrategy. The option identifiedin this Pegwell Bay toFlooding 2001Kingsdown coastal strategy isa ‘holding’ option untilcompletion and adoption ofthe Lower Stour River strategy.The preferred policy from theCatchment Flood ManagementPlan (CFMP) for this reach isto ‘Take action to increasefrequency of flooding to bringbenefits elsewhere’.Strategic optionDo nothingDo minimumActionsNo further work will be undertaken on the existing defencesThe condition of the existing defences would be monitored and any damagerepaired on a reactive basisDo minimum has been selected as a holding option until completion of the Lower Stour Riverstrategy. It is anticipated that managed realignment will be the preferred option in this reach toreduce flood risk to Canterbury. The viability and extent of this managed realignment will bedetermined by the Lower Stour River Strategy.16 Environment Agency Pegwell Bay to Kingsdown coastal strategy

NotesEnvironment Agency Pegwell Bay to Kingsdown coastal strategy 17

Notes18 Environment Agency Pegwell Bay to Kingsdown coastal strategy

Have your sayThis document is a summary of the options developed in partnership with Dover District Council andin line with government guidelines.We want to know what you think. Your opinions on the leading options are important:• Do you support the leading options?• Do you have ideas for improvements?• Do you have any other comments?Please send us your comments before 12th October 2007 to either of the following addresses.Please mark your envelope Pegwell Bay to Kingsdown Coastal Strategy.Environment AgencyOrchard HouseEndeavour ParkLondon RoadAddingtonWest MallingKent, ME19 5SHor email: pbk@environment-agency.gov.ukDover District CouncilWhite Cliff Business ParkDoverKentCT16 3PJFor additional copies please call 08708 506 506 (Mon - Fri 8-6). Or visit our websitewww.environment-agency.gov.uk/yourenv/consulation/current_consultations/What happens next?We will be holding public exhibitions in Sandwich and Deal.Dates and times will be advertised in advance in the local press.We will incorporate any comments that we receive into the strategy report. This will define theconstruction, improvement or maintenance works that are required in the next five years betweenPegwell Bay and Kingsdown, including up the River Stour through Sandwich. The strategy report willalso define an overall flood risk management plan for the next 100 years.The strategy will then be issued to the Department for Environment Food and Rural Affairs (Defra) forreview and approval.Environment Agency Pegwell Bay to Kingsdown coastal strategy 19

Would you like to find out more about us,or about your environment?Then call us on08708 506 506 (Mon-Fri 8-6)emailenquiries@environment-agency.gov.ukor visit our websitewww.environment-agency.gov.ukincident hotline 0800 80 70 60 (24hrs)floodline 0845 988 1188Environment first: This publication is printed on paper madefrom 100 per cent previously used waste. By-products frommaking the pulp and paper are used for composting and fertiliser, formaking cement and for generating energy.GESO0707BMZU-E-P