亞開行-海綿城市：整合綠色和灰色基礎(chǔ)設(shè)施增強(qiáng)中華人民共和國(guó)的氣候變化抵御能力（英）-2022.11-11正式版

NO.222NOVEMBER2022KEYPOINTSRapidlyincreasingurbanization,togetherwithclimatechange-relatedhazardsfromincreasedfrequencyandseverityofextremeweatherevents,requiresurgenturbanadaptation.Nature-basedsolutions(NbS)canenhanceclimateresilience,effectivelyreducingdisasterriskssuchasthosefromfloods,droughts,urbanheatislands,desertification,andlandslides.TheSpongeCityprograminthePeople’sRepublicofChina(PRC)supportswater-relatedNbSandgreeninfrastructure—suchaswetlands,waterretentionparks,raingardens,bioswales,perviouspavement,andgreenroofs—toimprovewatermanagementandreduceurbanrunoffandflooding,whiledeliveringmanyotherecosystembenefits.NbSandspongecitiesshouldbemainstreamed,deepened,andcombinedwithgrayinfrastructure.Todothisrequirespoliciesthatreprioritizeadaptation;technicalsupportforanalysis;risk-informedplanningtoretrofiturbanareas;andtheprioritizationoffunctionalgreenspaceplanning.Italsorequireseducationtoovercomereservationstoward,andinertiaagainst,implementingNbS.ISBN978-92-9269-771-6(print)ISBN978-92-9269-772-3(electronic)ISSN2071-7202(print)ISSN2218-2675(electronic)PublicationStockNo.BRF220416-2DOI:/10.22617/BRF220416-2

ADBBRIEFSSpongeCities:IntegratingGreenandGrayInfrastructuretoBuildClimateChangeResilienceinthePeople’sRepublicofChinaStefanRau*SeniorUrbanDevelopmentSpecialistEastAsiaDepartmentAsianDevelopmentBankUrbanizationandclimatechangehaveledtoadramaticincreaseinhazardssuchassea-levelrise,stormsurges,floods,droughts,extremeheat,anddesertification.Adaptingtotherisksofachangingclimateisimperativefornationalandlocalgovernments,anditrequiresbothstructuralmeasures(suchasinfrastructureinvestments)andnonstructuralmeasures(suchasdisasterpreparednessandearlywarningsystemsforfloodsandotherpotentialdisasters).Structuralmeasureshavetraditionallybeengrayinfrastructure,i.e.,concretewalls,dikes,drainagepipes,andstoragetanks.Greeninfrastructureandtheapplicationofnature-basedsolutions(NbS)howeverarenowvaluedmoreandarebeingusedincreasinglyaroundtheworld.ThePeople’sRepublicofChina(PRC)hasbeensupportingthedevelopmentofso-calledspongecitiessince2014.Aspongecityessentiallysoaksinrainwaterandretainsexcessstormwater,thenfiltersandreleasesthewaterslowly,muchlikeasponge.SpongecitiesprimarilyutilizeNbSlikewetlands,greenways,parks,raingardens,greenroofs,andbioswales.Ideally,grayandgreenmeasuresaresystemicallyintegratedandmutuallyreinforceoneanothertoachieveresilience,suchasbyusingharnessedrainwaterduringdryperiods.NbSprovidearangeofadditionalbenefitsfromecosystemservices,likeimprovementofairandwaterquality,morecoolingmicroclimates,andrecreationalgreenspacesforpeople.ThisnoteprovidesaninternationalperspectiveontheevolutionofthePRC’sSpongeCityprogramandlessonslearned.Itofferspossibleavenuesforimprovingtheconceptandintegratingitintothebroadercontextofurbanandregionalplanning,infrastructuredevelopment,andintegrateddisasterandfloodriskmanagementforthePRCandtherestofAsiaandthePacific.Note:ADBrecognizes“China”asthePeople’sRepublicofChina.Theauthorisgratefulforinputsviaprojectandtechnicalassistancework,cases,discussion,andpeerreviewfrom,amongothers,TianYing,HerbertDreiseitl,PhilipEnquist,PeterKindel,ZuoHeping,ZhengNengshi,CharlesRodgers,VirinderSharma,ArghyaSinhaRoy,StevenGoldfinch,IsaoEndo,SoniaChandSandhu,LaraArjan,RabindraOsti,MingyuanFan,JohnMatthews,SteveGawler,ChristinavonHaaren,andJeremyDawkins.ADBBRIEFSNO.222A.CHALLENGESOFURBANIZATIONANDCLIMATECHANGECitiesareheavilyaffectedbyclimatechange.Urbanizationandindustrializationalongwithopening-uppoliciessince1978ledtorapideconomicandurbangrowthinthePRC,withanurbanizationrateof64.7%(2021).1Urbanareasareseriouslyaffectedbyarapidlychangingclimate,threateninghumanlifeandhealth,infrastructureandassets,andalsoecosystemsandnature.Highervariabilityandmoreextremeweathereventsleadtomorefrequentandseverefloodswithhigherhumanandeconomiclosses.Increasingnumbersofcyclones,landslides,heatwaves,droughts,anddesertification,aswellassea-levelrise,adverselyimpactlivelihoodsandlocaleconomies.Disasterrisksareexacerbatedbyunsuitablelanduseandurbandevelopmentinflood-proneareas,andunintegratedfloodprotectionstructuresasopposedtowatershed-widefloodriskmanagement.Futureimpactsareexpectedtobeevenmorefrequentandsevere.2,3Flooding.Wedistinguishthreetypes:Urbanflooding(pluvialflooding).Coveringlandwithroads,buildings,andimpermeablehardpavementreducesnaturalinfiltrationandincreasesrunofffromrainwaterandstormwater.Riverflooding(fluvialflooding).Straighteningriverswithhardembankmentsandwalls,andnewroadslimitingspaceandreducingflowcapacityofrivers,increasestheriskofflashfloodingdownstream.Coastalflooding,stormsurges,andcyclones.ThePRC’scoastalregionisheavilyurbanized,andincludeslow-lyingmegacities.Cycloneshaveincreasedoverthelast20years,andtherateofpolaricemeltingsuggestssea-levelrisewillbefasterthanpreviouslyestimated.Heatwaves,droughts,andwildfires.Summersaregettinghotterandlonger,andurbanheatislandeffectsresultinhigherincidentsofprematuredeathsfromextremeheat.Temperaturesindenselybuilt-upareascanbeseveraldegreeshigherthaninurbanparksandruralareas.Outsidecities,droughtsandwildfirescauselossofecosystems,life,anddamagetoassets.4

Lossesanddamages.AsiaandthePacificishighlyexposedtohazardsandclimatechangeimpactsandsuffersmoredisastersandlossesthanotherregions.5Globally,during2000–2019,climate-relateddisasterskilledalmost716,000peopleandaffected3.3billionpeople.Directlossestophysicalassetstotaled$676billion,ofwhich27%wasinAsiaandthePacific.Floodinghasaccountedforabout40%ofalllossesfromdisasterstriggeredbynaturalhazardssince1980,with4,588flooddisastersacross172countriesleadingtomorethan250,000peoplekilled,anddamagesexceeding$1trillion.6Recenteventsprovideagrimglimpseintothefuture.Globally,in2020,therewere26%morestormsthantheannualaverageof102events,23%morefloodsthantheannualaverageof163events,and18%moreflooddeathsthantheannualaverageof5,233deaths.ThePRCfacedsignificantfloodingacrossthecountrythatkilled397people,affected14.3millionpeople,andcaused$21.8billionineconomiclosses(footnote3).Droughtsandheatwavesareexpectedtobeveryseverewithmostprematuredeathscausedbyclimatechangealreadyattributedtoheatwavesglobally.7ThePRCfacesincreasingdisasterriskfromclimatechange.Climatechange-relatedtemperatureincreasesinthePRCwilllikelybeabovetheglobalaverage.Riskofdroughts,floods,andheatwaveswillincrease,resultingingreaterlossesandmoredamage.Theselosseswillbechallengingtoavoidwithoutmajoradaptationplansandinvestmentsineffectivedisasterriskmanagement.Theimpactswilllikelybeexperiencedmoststronglybylow-incomehouseholdsandcommunities.Increasedurbanheatislandeffectisasignificantthreattohumanhealth,productivitylevels,andenergydemand.8B.EVOLUTIONFROMGRAYTOGREENINFRASTRUCTUREANDSPONGECITIESThroughouthistory,villagesandtownswerelocatedclosetorivers.Asidefrombeingawatersource,riverswerealsousedforenergygenerationsupportingagricultureandcraftsmanship.Earlycommunitiesbalancedtheriskofbeing12345678

S.Rau.2021.BridgetoFutureLivableCitiesandCityClustersinthePeople’sRepublicofChina:PolicyOpportunitiesforHigh-QualityUrbanDevelopment.ADBEastAsiaWorkingPaperSeries.No.40.Manila:ADB.Thispublicationprovidesanoverview,extensiveresourcelist,andpolicyoptionsincludingforclimatechangeadaptationandmitigationandforgreendevelopment.A.Revietal.2014.UrbanAreas.InIntergovernmentalPanelonClimateChange(IPCC).ClimateChange2014:Impacts,Adaptation,andVulnerability.PartA:GlobalandSectoralAspects.ContributionofWorkingGroupIItotheFifthAssessmentReportoftheIPCC.TheIPCC’sSixthAssessmentReportexpectstheclimatetochangemuchfasterthantodate,withanincreasednumberandseverityofhazards.IPCC.2021.RegionalFactSheetAsia.InV.Masson-Delmotteetal.,eds.ClimateChange2021:ThePhysicalScienceBasis.ContributionofWorkingGroupItotheSixthAssessmentReportoftheIPCC.CambridgeUniversityPress.TheNationalAeronauticsandSpaceAdministration(NASA)recordedmassivewildfiresin2021.NASAEarthData.FireInformationforResourceManagementSystem(FIRMS)(accessed23August2021).T.KesslerandA.Chatterjee.2021.BuildingDisasterResilienceinCitiesinAsiaandthePacific.InB.SusantonoandR.Guild,eds.CreatingLivableAsianCities.Manila:ADB.M.McLennan.2021.SunkCosts:TheSocioeconomicImpactsofFlooding.RethinkingFloodSeries,Report1.UnitedNationsOfficeforDisasterRiskReduction.2019.GlobalAssessmentReportonDisasterRiskReduction.Geneva.(Withaspecialsectionondroughtrisk,oftenunderestimatedand“hidden”).WorldBankandADB.2021.ClimateRiskCountryProfile:China.Washington,DCandManila.2SpongeCities:IntegratingGreenandGrayInfrastructuretoBuildResiliencefloodedwithbeingnearthisessentialpublicgood.Today,largesprawlingcitieswithcarsandpavedsurfaceseverywherecausesignificanturbanrunoffandincreaseriskofflooding.Flooddefensetypicallyconsistedoftheconstructionofgrayinfrastructure,i.e.,concrete,steel,orPVCfloodwallsanddikes,drainagepipes,deeptunnelsystems,andstoragetanks.Hydrologyengineeringhandbooksandsimulationsoftwareweredevelopedfortheseengineeredflooddefensesystems,whicharelargelystillinplace.Nature-basedsolutionswererediscoveredaseffectiveandefficientmeanstomanageclimatechange-relatedhazardsanddisasterrisks.In2016,theWorldConservationCongressandInternationalUnionfortheConservationofNaturedefinedNbSas“actionstoprotect,sustainablymanage,andrestorenaturalormodifiedecosystems,thataddresssocietalchallengeseffectivelyandadaptively,simultaneouslyprovidinghumanwell-beingandbiodiversitybenefits.”9Similarconceptsareappliedaroundtheworldunderdifferentnames,includinglow-impactdesign,water-sensitiveurbandesign,greeninfrastructure,orsustainablerainwatermanagement.10Aspongecityisonethatactslikeasponge,soakingupandretainingwaterduringrainandstormsandreleasingitslowly.Theideaborrowsconceptsfrompriorlow-impactdevelopmentapproachesfromaroundtheworld,andtheterm“spongecity”waspopularizedinthePRCsince2013.Anationalgovernmentprogramsupportingpilotspongecitiesstartedin2015,andadirectiverequestingallcitiestopreparespongecitymasterplansfollowedin2017.DevelopingaspongecityhelpsrespondtofourkeywaterchallengesfacinghighlyurbanizedareasinthePRC:toomuchwater,toolittlewater,pollutedwater,andmuddywater.ThePRC’stermhasinspiredothercities,e.g.,Germany’sBerlinandHamburg,whereinitiativesusingthatnamearebeingplannedandimplemented.Spongecitiesaimtoimprovemanagementoflocalwatercycles.Rainwaterandstormwaterismanagedlocallyasopposedtobeingcentralizedforthewholecity.Managementoffloodrisk,waterscarcity,andpollutionareintegrated.Whenplanningaspongecityforanurbanarea,climatechangeandtheextremestorms,longerdryperiods,andextremeheatitcausesshouldbeconsidered.Onemainprincipleistousefunctionallydesignedgreenspaces,suchaswetlands,floodplains,andgentleembankmentslopes,toincreasedetentionandflowcapacitytoimprovemanagementofriverflooding.Toimprovemanagementofurbanflooding,greeninfrastructureisapplied,designedtoretainanddeceleratestormwaterbeforeitflowsintodrainage

pipesandcanals.Beforethefirst-flushofstormwatergoesintoriversitshouldbetreatedinvegetatedsedimentationpondsandearthfilters.Thedestructiveforceofstormwaterisremovedbystoringitandslowingitdown.Toreducedamageandhealthimpacts,rainwateriscapturedduringstormsandreusedindryperiodswhenlesswaterisavailableforwateringgreenspacesandcleaningstreets,andforusebyindustry.ThisconceptcontributestowatersecurityinthenorthernPRC,wherewaterresourcesarescarce,throughharnessingrainwaterforlaterreuse,whileinthesouthernPRC,whereprecipitationishigh,itisusedmainlytoreduceflooding.Asextremeweathereventsareprojectedtoincrease,heavierstormswithfloodsinthenorthandmoredroughtsinthesouthareexpected.Therefore,spongecityobjectivesareconvergingacrossthePRC,whileeachcityhasitsspecificclimateriskstobeconsideredinitsplanningasaresilientspongecity.C.POLICYCONTEXTTheNationalNew-TypeUrbanizationPlan(2014–2020)includedtheconstructionofspongecitiesandotherrelatedobjectives,likebuildingan“ecologicalcivilization”throughsustainabledevelopmentandimprovedenvironmentalprotectionandmanagement.Italsoincludedclimatemitigationandadaptationthroughenergyconservationandemissionsreductions.Furtherurban–ruralintegrationandsociallyinclusivedevelopmentwithstrongersocialprotectionandimprovedruralopportunities,andinstitutionalandtaxreform,werealsoincludedintheplan.TheNationalClimateChangeAdaptationStrategy(2013)andtherecentlyamendedstrategy(June2022)includeawholerangeofadaptationmeasuresandactions,disasterriskmanagementandresponse.11Specifically,theyincludeenvironmentalprotectionandecologicalrestoration;coastalregionadaptationandcoastalwetlandandreefrehabilitation;(iii)urbanflood,drought,heatwave,anddesertificationriskmanagement,inclusiveofecosystem-basedadaptation;(iv)improvedfarmlandirrigation,watersafety,andefficiency;(v)urbanandruralwatersecurityandsafety;andinfrastructureupgradeandresilience.TheUrbanClimateChangeAdaptationActionPlan(2016)covered28pilotcities.12Thenationalgovernmentrequestedallcitiestoenactpolicies,regulations,systems,andmechanismsWorldConservationCongressandInternationalUnionfortheConservationofNature.2016Resolution.WCC-2016-Res-069-EN:DefiningNature-BasedSolutions.L.Arjan,S.Rau,andS.C.Sandhu.2021.IncreasingUrbanResiliencethroughNature-basedSolutionsandTotalAssetManagement.InB.SusantonoandR.Guild,eds.CreatingLivableAsianCities.Manila:ADB.GovernmentofthePRC,StateCouncil.2013.NationalClimateChangeAdaptationStrategy.Beijing;andGovernmentofthePRC,StateCouncil.2022.NationalClimateChangeAdaptationStrategy.Beijing.GovernmentofthePRC,NationalDevelopmentandReformCommission,andMinistryofHousingandUrban–RuralDevelopment.2016.ActionPlanforUrbanAdaptationtoClimateChange.Beijing.3ADBBRIEFSNO.222toimproveandintegrateadaptationactionintotheiroverallurbanplanning.Theywereaskedtodevelopandenhancestandardsandconstructionandmanagementspecificationstoimproveresilience.Furthermore,theplancalledforcitiestoimproveinstitutionsanddevelopanintegratedadaptationconcepttolinkurbanplanning,landuse,transport,infrastructure,energy,water,drainage,andopenspaceplanning,andimproveecologyandresilienceofbuildingsandinfrastructure.Conceptsshouldstrengthenurbangreenspacesystemsalignedwithriversandventilationcorridors.13TheUrban–RuralEnvironmentalRedlinewasrequiredatthemunicipallevelinthe13thFive-YearPlan,2016–2020.Ithadbeenincludedonalargescaleinthenational11thFive-YearPlan,2006–2010,definedasfourfunctionalareas,includingurbanconcentrationzonesandenvironmentalprotectionzones,or“redlines”withrigorousrestrictionsofhumanactivities.AsianDevelopmentBank(ADB)technicalassistancesupportedthedevelopmentoftechnicalguidelinesandmethodsandpreparationofurban–ruralenvironmentalredlineplansforpilotcities.14D.SPONGECITYGUIDELINESANDPILOTPROGRAMTheMinistryofHousingandUrban–RuralDevelopmentpublishedTechnicalGuidelinesforSpongeCityConstructioninthePeople’sRepublicofChinain2014.15Theseguidelinescallfortheintegrationofspongecityprinciplesinalllevelsofplanning,design,andconstruction.Itcallsforanalysisandconservationofsurfacewaterandgreenspaces,andgreenengineeringresponses.Itincludesrecommendationsforlocalinstitutionalcoordination,scientificapproachtoriskanalysis,risk-informedplanning,andacatalogueofpotentialmeasures(Box1).TheNationalSpongeCityPilotProgramwaslaunchedin2015intwophasesandsupported30pilotcities.Thepilotcitiescompletedalmost5,000projectscontributingtofloodriskreduction.AcrosscitiesinthePRC,approximately56,000kilometersofgreenwaysand72,400squarekilometersofgreenparkswerebuilt,contributingtoresilienceandimprovedlivability.TheGovernmentofthePRCrequestedthatallcitiesinthecountry

Box1:TechnicalGuidelinesforSpongeCityConstructioninthePeople’sRepublicofChinaThesecomprehensiveguidelinesinstructcitiestoassessandplanacomprehensivespongecityapproachonintegratingalllevelsofplanninganddesign,fromstrategicurbanandregionalplanningtodetailedsite,roadandbuildingdesign,construction,andmaintenance.Specifically,itprovidesguidanceonintegratingspongecityin(i)strategicurbanmasterplanning,(ii)landuseplanning,(iii)waterandgreenspacesystemsplanning,detailedcontrolplanning,(v)sitedesign,(vi)buildingplanningandconstruction,and(vii)roaddesign.Theoverarchingprincipleislow-impactdevelopment,conservationandprotectionofrivers,wetlands,andotherwater-relatedandgreen-spaceecosystems;theenhancementofthehydrologicalfunctionsoftheseareas;andtheintegrationofthemintourbanareas.Theguidelinesincludeestablishmentofnational,regional,andcity-specifictargetsforrunoffreduction,andstoragecapacitiesofrainwaterandstormwater.Theoverallnationaltargetofan80%reductionofurbanrunoffisveryambitious.Theguidelinesrecommendspecificmeasuresthatshouldbeconsideredandintegrated,suchaspermeablepaving,greenroofs,sunkengreenspaces,biologicalretentionfacilities,infiltration,wetandregulatingponds,seepagewells,rainwaterwetlands,rainwatertanks,conditioningtanks,grassditches,seepagepipes/drains,vegetationbufferzones,initialrainwaterabandonmentfacilities,andartificialsoilinfiltration.Source:MinistryofHousingandUrban–RuralDevelopment.2014.TechnicalGuidelinesforSpongeCityConstructioninthePeople’sRepublicofChina.Beijing.preparespongecitymasterplansin2016,andby2018,538citieshadcompletedtheirfirstspongecityplans.PilotsandcasesofADBsupport.ADBsupportedaboutsevenprojectsthatinvolvedspongecityinfrastructure,includingaloantooneoftheoriginal16spongecitypilots—PingxianginJiangxiProvince(Box2).ADB.PRC:MainstreamingUrbanClimateChangeAdaptationinthePeople’sRepublicofChina.ADB.PRC:InstitutionalizationofUrban–RuralEnvironmentalMasterPlanningtoGuideEnvironmentallySustainableUrbanizationinthePeople’sRepublicofChina.MinistryofHousingandUrban–RuralDevelopment.2014.TechnicalGuidelinesforSpongeCityConstructioninthePeople’sRepublicofChina.Beijing.4SpongeCities:IntegratingGreenandGrayInfrastructuretoBuildResilienceBox2:JiangxiPingxiangIntegratedRural–UrbanInfrastructureDevelopmentProjectFloodriskreductionisatoppriorityinPingxiang,JiangxiProvince.Since1998,floodinghassignificantlyincreasedinfrequencyandseverity.AnAsianDevelopmentBank(ADB)projectcontributedtoPingxiang’spilotspongecitydesignbyaimingtoreduceriverfloodingtofourkeysubcenters,awhilethenationalgovernmentprogramfocusedonPingxiang’scoreurbanarea.TheADBprojectshiftedtheconventionalapproachtofloodcontrolawayfrompurelyconsideringgrayinfrastructure.Ecologicalriverrehabilitationwasintegratedwithmanagementoffloodrisk,improvingclimateresilienceandbiodiversity,and

increasingurbangreenareas,therebyalsoimprovinglivabilityandcompetitivenessofthecity.Morepubliclyaccessiblegreenspacewasprovidedtotheriversurrounds,withgentlyslopedgreenembankmentsandwateredgesthatallowforchangesinwaterlevelsthroughouttheyearandreducefloodsafterheavyrains,whilealsoenhancingwaterecologyandquality.Climateriskandvulnerabilityassessmentsandhydraulicmodelingwerecarriedoutandproposedadaptationmeasureswereincludedintheproject.Meanwhile,protectedfloodplainsandwetlandsretainstormwater,andseparatedrainageandsewerpipeswereinstalled.Restoredriversidewetlandsandgentlegreenslopesalongtheriverreducefloodrisk.Theyalsocreateahabitatforbiodiversefloraandfaunaandareenjoyedbylocalcommunitiesduringtimesofnormalwaterlevels(photosbyStefanRau).ADB.People’sRepublicofChina:JiangxiPingxiangIntegratedRural–UrbanInfrastructureDevelopmentProject.Source:StefanRau.Sincelearninglessonsfrominvolvementinearlyprojects,ADBevolvedtoadoptamorecomprehensiveapproachtoclimateriskandadaptationoptionsassessments,inclusiveofclimateforecastingthroughlocalizingglobalclimatemodelsandscenarios.Laterprojectshaveappliedhydrologicalandhydraulicmodeling,

integratingfluvialandpluvialfloodingrisks,andsystemicallyintegratinggreenandgrayinfrastructure,whichwasdevelopedanddemonstratedintheJilinYanjiproject(Box3).Meanwhile,aprojectinAnhuiProvincehasdemonstratedthemultiplebenefitsfromrehabilitatedwetlands(Box4).5ADBBRIEFSNO.222Box3:JilinYanjiLow-CarbonClimate-ResilientHealthyCityProjectInrecentyears,Yanjihassufferedfromurbanfloodingforabout5daysannuallyduetoanoutdatedcombinednetworkofseweranddrainagepipesandtopavingareasaddedduringurbanexpansion.WithAsianDevelopmentBanksupport,Yanjiissettobuildthefirstbusrapidtransit(BRT)corridorinthenortheastofthePeople’sRepublicofChina.aTheBRTwillbeintegratedwithcomprehensivestormwatermanagementandwatersupplysystemimprovements.Theprojectconceptappliestransit-orienteddevelopmentprinciples.Theseincludedevelopingmixed-use,high-density,andpedestrian-friendlyurbansubcentersaroundBRTstations,withmorepublicgreenspaces.Thisenableslow-carbonlifestyleoptionsandmobility.Thesesubcenterswillbeconnectedbynewlyestablishedgreenspacesalsolinkingproject-supportedimprovedriverfrontgreenways.Allareplannedasgreeninfrastructure,applyingspongecityprinciples.Allthesespaceswillresultfromtheapplicationofuniversaldesign

principlescontributingtoahealthyandage-inclusivecity,ensuringaccessibility,andenablinghealthylifestylesforallpeople.Theprojectpreparedaspongecitymasterplanandclimateriskandadaptationoptionsassessment.Theprojectdevelopedanadvanceddigitaltoolcomprisingahydraulicmodelthatcansimulatefuturestormsandincludeadaptationmeasures.Thismodelintegratesintothesystemthecurrentandnewlyproposedgreenandgrayinfrastructure,mainlytheimprovedlayoutofundergrounddrainagepipesandchannelscombinedwiththenewspongecitygreeninfrastructureontheground.Thecapacitiesofthedrainagenetworkandflowcapacitytoretainandinfiltratestormwaterwerequantifiedandmodeledoptimizingreductionoffloodrisk,andmaximizingbenefitsofpublicgreenspacesandecosystembenefits.SpongeCity.Sp