Seite - 302 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

302 W.J.WouterBotzenet al. and building codes are powerful tools for controlling land use and urban develop- ment,andhence(changesin-) future landuse(Burbyetal.2000).Assuch,zoningis increasingly seenas an important tool in climate adaptationandmanagingchanges inweather extremesdue toclimatechange (Aerts andBotzen2011). Zoningencompasses thefollowinggeneralpoliciesrelatedtourbandevelopment and riskmanagement: • Restrictions: Based on hazardmaps and or additional risk information, zoning policiesmay indicate that incertainareasurbandevelopment isnot allowed; • Conditional development:Urbandevelopment is allowed in riskyareas, but only whencertainconditionsaremet,forexample,by(a)implementingbuildingcodes, (b) homeowners have purchased insurance against natural hazard risk (c) buffer zonesare respected:buildingdevelopment isonlyallowedwhenappropriatedis- tancesbetweenestablishmentsandvulnerable riskareasaremaintained. Box12.3Effectiveness of flooddamagemitigationmeasures inGermany Kreibichetal.(2005)interviewed1248householdsthatwereaffectedbythesevereElbe floodin2002inGermanyinorder toassess the levelofpreparednessofhouseholdsfor flooding, and to estimate the effectivenessofdamagemitigationmeasures that house- holdsimplementedbeforeandduringtheflood.Meancomparisontestswereconducted toexaminehowflooddamagediffersbetweenhouseholdswhohave,orhavenot,imple- menteda specificflooddamagemitigationmeasure.Overall, this studyshows that the potentialgainsof implementingmitigationmeasuresat thehouseholdlevelcanbesub- stantial.Theresultsshowthatbuildingswithoutacellarsufferabout24%lessbuilding damageand22%lessdamagetocontents.Waterbarriersreducedflooddamagebyabout 29%.Stablebuildingfoundationorwaterproofsealedcellarwallsreducedflooddamage to buildings by about 24%.Themost effective strategieswereflood-adaptedbuilding use andflood-adapted interior fitting. Flood-adapted building usemeans that parts of thebuilding thatcanbeflooded(suchas thecellarandgroundfloor)arenotusedcost- intensivelyor includeexpensiveconstructions, suchasasauna.Flood-adapted interior fittingmeans that onlywaterproofedbuildingmaterial and furniture andcontents that can be easilymoved to higher floors are applied in flood-prone parts of the building. Flood-adaptedbuildingusereduceddamagetobuildingsandcontentsby, respectively, 46 and 48%,while flood-adapted interior fitting saved damage to both buildings and contentsby53%.Placingutilityandelectricalinstallationonhigherfloorsreducesflood damageby36%.Theseresultsof theeffectivenessoffloodmitigationmeasures inGer- manyhavebeen confirmedbyKreibich andThieken (2009)whoconducted a similar surveyafterfloods in2005and2006 in the cityofDresden.The results of this survey indicate thathouseholdpreparedness improvedbefore the2005/2006floods,compared with the2002Elbeflood,and that this improvedpreparedness resulted insignificantly less flood damage in the events.Kreibich et al. (2011) show that the implementation of low-costmitigationmeasures, such as the securing of oil tanks and installation of mobilefloodwalls,arecost-effectiveinGermanyunderarangeoffloodconditionsand discount rates.Source (Botzen2013)