threat from floodingthreat from flooding · 2017. 3. 20. · threat from floodingthreat from...
Transcript of threat from floodingthreat from flooding · 2017. 3. 20. · threat from floodingthreat from...
threat from floodingthreat from floodingthreat from flooding
Resilience and ‘building back better’ • Theaverageamountoftimethatpeople
spendoutoftheirflood-damagedhomesisninemonths.
• Bytakingpracticalstepstoincreasetheresistanceandresilienceofapropertytoflooding,thetimetakentorecoverfromfloodingcanbeshortenedconsiderably.Thevalueofaclaimsubmittedbyinsurerscanbereducedorhome-ownerscanremovetheneedtoclaimatall.
• Butinstallingproperty-levelresilienceandresistancemeasuresisnotyetstandardpracticeinfloodaffectedareas.Reasonsincludeadesireonthepartofhouseholderstogetbackintotheirpropertiesquicklyafterflooding,ratherthanwaitformeasurestobeinstalled,andalackoftrustintheeffectivenessofthemeasures.
• Resistancemeasuresaredesignedtoslowdowntheflowofwaterintoaproperty,buyingvaluabletimetomovefurnitureandpossessions.Measuresinclude:floodbarriers,strengtheneddoorsandwindows,floodalarmsandgardenlandscaping.Resiliencemeasuresareaimedatamelioratingflooddamageoncewaterhaspenetratedtheproperty.Theseincludestainlesssteelkitchens,extensivewallandfloortiling,waterproofgroutandadhesive,removablestaircarpetandquickrelease,removableinternaldoors.
CASE STUDY: Slowing the Flow in Pickering ANaturalFloodManagementschemefromPickering,‘SlowtheFlow’,wasdeclaredasuccessin2016,followinganevaluationbytheEnvironmentAgency.Theschemeconsistedof167‘leaky’damsand187heatherbaledamswithinastream,twotimberbunds(part-concretestructuresaimedatdivertingwaterawayfromthetown),andimprovementstofarmland,woodlandandmoorlandintherivercatchment.40,000treeswereplantedandanupstreamstoragereservoirinstalled.ThecommunityinPickeringwasdirectlyinvolvedinthedesignofthescheme,facilitatedbygeographerProfessorSarahWhatmoreandcolleaguesfromtheUniversityofOxford.
TheEnvironmentAgency’sanalysisconcludedthattheschemepreventedfloodinginPickeringaroundChristmas2015,thatwouldotherwisehaveoccurredtoasmallnumberofresidentialpropertiesandthetown’smuseum.Thefloodpeakwasreducedby15-20%,withhalfofthiseffectattributabletoimprovedcatchmentmanagementandtreeplantingandhalftothefloodstoragereservoir.
The Bonfield ReviewA2016reportsuggestedtheuseofBuildingRegulationstoencouragefloodresilientandresistantconstruction,alongwiththeintroductionofindustrystandardsandcertificationprocessesforfloodproductsandtheirinstallation.
Changes in land useUpsteamchangesinlandusecanaffectdownstreamflooding.Forexample,treefelling,increaseddensitiesoflivestockandthemodificationofriverchannelscanleadtoerosionandincreasedrun-off.Suggestedsolutionshaveincludedtheremovalofleveestoreactivatefloodplains,strategictreeplantingandthereversalofsoildegradationtoincreaseinfiltrationcapacity.
TheGovernmenthasrecognisedfloodingasoneofthemostseriousthreatsfacingtheUnitedKingdom:the2017ClimateChangeRiskAssessmentidentifiedfloodingandcoastalchangeriskstocommunities,
businessesandinfrastructureasthegreatestriskposedtotheUKbyachangingclimate.Landusepracticesandprojectedincreasesinheavyrainfallmeanthatthethreatfromfloodingissevereandincreasing.
Winter floods 2015/16• AnalysisbytheCentreforEcology
andHydrologyshowsthatthewinterfloodingeventof2015/16,causedbystormsDesmond,EvaandFrank,wasoneofthemostsevereandextremehydrologicaleventsofthepast100years.
• December2015wasthewettestDecemberonrecord,andthewettestcalendarmonthsincerecordsbeganin2010.
• Itisestimatedthat16,000propertieswerefloodedinEnglandand20,000moreprotectedfromfloodsbyexistingdefences.
• KPMGhasestimatedtheeconomicimpactofthe2015/16winterfloodsat£5billion-£5.8billion.
sources: figure 1: the winter floods of 2015/2016 in the uk - a review. centre for ecology & hydrology; figure 2: flood risk & management and funding, house of commons library. design + illustration: www.greg-stevenson.co.uk
Natural Flood Management• NaturalFloodManagementisthe
alteration,restorationoruseoflandscapefeaturestoreducefloodrisk.Alteringfeaturesoftenincludes‘soft-engineering’,whichhasbeendefinedasengineeringwithnaturalmaterials,suchassoil.
• Althoughtheevidenceislimited,thereareindicationsthatNaturalFloodManagementhasagreaterroletoplayinsustainablefloodriskmanagementintheUKthanitdoesatpresent.Itcanbeeffectivewhenusedaspartofaportfolioofmeasures,includingplanning,infrastructuredesignandregulation,tailoredtothegeographyofthecatchment.Therearealsowidersocial,environmentalandeconomicbenefitstonaturalfloodmanagement,includingbenefitsforbiodiversity.
• ThesuccessofNaturalFloodManagementdependsonthecatchmentscale,thescaleofthefloodinginvolved,thewillingnessoflandownerstocooperateandtheneedsofthecommunitiesatrisk.
• ThereispresentlyalackofevidencefortheefficacyofNaturalFloodManagementatlargerscalesandaneedtofillthisresearchgap.
Figure 1: November2015–January2016rivercatchmentoutflowsthehighestsincerecordsbeganin1960s
Funding for flood risk managementTheGovernmenthascommitted£3.2billionfornewflooddefences,maintenanceandrepair,upuntil2021.
Figure 2: UKGovernmentspendingonfloodandcoastalerosionriskmanagement2000–2017
CASE STUDY: Cumbria CumbriawastheworsthitareaoftheUK,withwaterlevelsinthemainriversexceedingthehighesteverrecorded.*
12monthsonfromtheaftermathofStormDesmond,oneinfivehouseholdswereyettoreturnhome.
“AcrossCumbria,1,029businesseswerefloodedthatday;ofthese,76percentareoperationalagain,while24percentremainclosed.200roadsorbridgeshaveyettobefullyrepaired,althoughmostareinuseagain.”
*Geographicalarticle:socialimpactsoffloodinginCumbria(“InRecovery–12monthsonfromStormDesmond”byKarenLloyd,Geographical,18January2017)
“It was the speed of it that was so shocking. Between 4pm and 5pm the water was rising at an inch a minute. By 5pm we were up to our chests.” ChrisWhite,Resident,Cumbria
Flooding from sea
Land use changes
Flooding from
rivers
Overloaded sewers
<2000/1 2016/17>
<1960s 2015/16>