Seite - 299 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

12 IntegratedDisasterRiskManagementandAdaptation 299 called a “qualitative CBA.” Box 12.2 describes how a combination of BCA and MCAhave guided “Room for theRiver”measures in theNetherlandswhich have contributedtoimprovingdischargecapacitiesofriversaswellasenvironmentalval- ues.Recently, robustdecision-makingapproaches (RDMA)havegained increasing attention, especially in the context of climate change adaptation (seeWatkiss et al. 2015forareview).RDMAapproachesincludequalitativeandquantitativemethods. Theyareparticularlyuseful toappraise long-terminvestments in thefaceof largeor “deep”uncertaintyabout the future. Insuchcircumstances itmaynotbepossible to make optimal decisions (as supported byCBA), but to select options that perform relativelywell across a rangeofpossible futures, and thus tominimise regret about anoptionwhen the future turnsout tobeverydifferent thanoriginallyenvisioned. Box 12.2 The use of CBA and MCA in flood risk protection policy in the Nether- lands TheNetherlandsisbyitsgeographicaldispositionnotoriouslyexposedtoextremeflood- ing.Morethanhalfof its landareafacesfloodrisks,puttingtwo-thirdsofitspopulation and 70%of itsGDP at risk. FloodProtection policy employs a so-called ‘multilayer safetyapproach,’ encompassingprevention, spatial solutions (includingadaptations to buildings and infrastructure), and crisismanagement,wherebypreventionofflooding receivesprominent attention.On the requestof theDeltaCommittee,whichwascom- missioned1958 after a hugeflood, themathematicianVanDantzig designed an algo- rithm to determine optimal dike heights based on the equilibrium betweenmarginal investment costs andmarginal expected avoidedflooddamage.ThefirstDeltaAct of 1958 includedfloodprotectionstandards forcoastalareas,whichwerepartlybasedon theworkofVanDantzig (1956).Asof the1970s, safetynormswereassigned to rivers and since1996allwater safetynormshavebeenwritten in law.ThisWaterActdeter- mines flood protection standards for all dike-ring areas (polders) in theNetherlands. However, the standards of the 1950s did not take account of the possible impacts of climatechangeandsea level rise. In response tonearflooding events in 1993and1995analternative approach toflood protection using dikes has been promoted in the Netherlands which entails improv- ingdischargecapacitiesof riversusing landusechange, restorationoffloodplainsand the creation of wetlands. These alternative flood control policies called “Room for the River” create side-benefits, such as ecological, recreational and amenity values. BrouwerandvanEk(2004)appliedaCBAandanMCAtoappraise the“Roomfor the River”measures.Theseevaluationsconsidered thehydrological,ecological, economic andsocialeffects.TheextendedCBAincludedmonetarybenefitsofenvironmentaland social benefits of themeasures and prevented flood damages. The estimatedNPV is e860million,whichfavoursinvestinginthesemeasures.Moreover,stakeholderanaly- siswasusedtoassesseffectsof thesepoliciesoninhabitants, farmers, theenvironment, watersupplycompaniesandrecreation.TheseeffectswereincludedintheMCAwhich also positively evaluated the “Room for theRiver”measures. In themeantime,most of thesemeasureshavenowbeen implemented inpractice.AsecondDeltaCommittee advised on an update of the flood protection standards in the light of the growth of exposedpopulationandassets,andprojectedsea-level rise.TheCommitteeupheld the firstDeltaCommittee’s risk-basedapproachandadvised that thenewstandardsshould