低影响开发报告

LIDPracticesHistory,CurrentStatusandFutureOutlookShawL.YuUniversityofVirginiaPresentedatTianjinPlanning&DesignInst.Tianjin,ChinaDecember22,2014Contents•LowImpactDevelopmentPractices–Howtheyallgotstarted.•BasicPrinciplesofLID•HydrologyandWaterQuality•CurrentStatus–Implementation,CaseStudies,CostConsiderations,etc.•FutureOutlook–Strategies,ResearchNeeds,etc.LIDDefined(USEPA)•LowImpactDevelopment(LID)isaninnovativestormwatermanagementapproachwithabasicprincipleofmanagingrunoffatthesourceusingdistributedsmall-scalecontrols.Thegoalistomimicasite'spredevelopmenthydrologybyusingtechniquesthatinfiltrate,filter,store,evaporate,anddetainrunoffclosetoitssource.•AlmostallcomponentsoftheurbanenvironmenthavethepotentialtoserveasanLIDpractice.Thisincludesnotonlyopenspace,butalsorooftops,streetscapes,parkinglots,sidewalks,andmedians.LIDisaversatileapproachthatcanbeappliedequallywelltonewdevelopment,urbanretrofits,andredevelopment/revitalizationprojects.NotanUmbrella–Puta“LID”onit!•WhatareLIDandGI?–LowImpactDevelopment(LID)–GreenInfrastructure(GI)-InnovativeStormwaterManagementApproachandSustainableDesign•BasicPrinciples:–Managerainfallatthesource(lotlevel)–Usesmall,cost-effectivelandscapefeatures–Mimicpredevelopmentconditions•EnvironmentallyFriendly–Aimstoreducerunoff(andCSOs),improvewaterquality,aquaticresources,andnaturalhydrology低影响開發技術在美國的發展•1980年代：喬治王子郡以植生滯留槽為基礎發展LID設計理念•1999年：喬治王子郡編制出第一部綜合性LID設計技術手冊•2000-2005年：LID設計理念快速得到了美國聯邦政府、各州政府及地方政府的認可.第一屆LID技術研討會.•2006-2010年：美國聯邦環保局正式認可LID設計理念應用于暴雨管理和面源污染控制設計。隨後大批全國性和地方性設計標準和設計手冊被開發出來.•同時在這階段，其他國家和政府也開始LID的應用和立法工作.Forexample,SUDSinEurope;LIDapplicationsinCanada;“Soak-away”gardensinSingapore,etc.StormwaterPhilosophyOld:MakeitgoasfarawayaspossibleasfastaspossibleNew:Slowitdown,cleanitup,soakitinControlpeakflowstomaintainpredevelopmentconditions–nowaterqualityControlpeakflowsand80%TSSremovalTheNeedforStormwaterManagement–Quantityand……..•NPSPollution(NPS),unlikepollutionfromindustrial&domesticwastewaterdischarges(PointsourceorPS)comesfrommanydiffusesourcesandisusuallycausedbyrainfallorsnowmeltrunoff•NPSpollutantsinclude:Excessivefertilizers,herbicides&insecticidesfromagriculturallands&urbanareasOil,grease&toxicchemicalsSedimentfromerosion&washoffSaltfromirrigation,deicingpracticesandaciddrainagefromminesBacteria&nutrientsfromlivestock,petwaste,etc.Heavymetalsfromindustrialsites,highways,etc.FeitsuiWaterQualityConcerns–SiltationandEutrophication.MainSourcesofPollution–TeaGardens,UrbanAreas,Roads.China–Taihu(3rdlargestfreshwaterlakeinChina)AlgalBloom2007AlgaeBloomBlockedWaterSuppliestoMillionsofPeopleinWuxiSummerof2007Chinatospend$14.5billiontocleanupLakeTaihuStormwaterControl–BestManagementPractices(BMPs)•Structuralandnon-structuralBMPs•Non-structuralBMPsaimatremovingorreducingpollutantatthesource,e.g.,streetsweeping,fertilizermanagement.•StructuralBMPsusemainlystorageandinfiltrationmechanismsforremovingpollutants•Inearlyyears,mainlydetentionponds.NowLIDpracticesarepreferredforurbanareas.Bufferstripsandwetlandsarepreferableforagriculturalareas.LIDPracticesBasicPrinciplesHowDoYouTransform•Hydrology(flowrate,volume)•WaterQuality?WhatisLID?Designfeaturesandpracticesdistributedthroughouturbandevelopmentthat:DisconnectImperviousSurfacesMimicNaturalHydrologicProcessesReduceRunoffRates&VolumesReducePollutantLoadsIntroductionLIDsaresourcecontrolpractices.Examples:1.Green/vegetated/eco-roofs2.Raingardens/bioretention/landscapeswales3.Rainwatercisterns4.Compostamendedsoils5.Porouspavements贴近自然，还原生态21世纪的雨水管理低影响开发式（LowImpactDevelopment)•综合的方式–从规划开始–防止为先，治理为后.•雨水管理的目标–源头削减–径流量，径流峰值–水质–地下水回补–河流的生态修复ExamplesofstormwaterLIDsGreenroofsExamplesofstormwaterLIDsRaingarden/bioretention/landscapeswaleExamplesofstormwaterLIDsRaingarden/bioretention/landscapeswaleExamplesofstormwaterLIDsCompostamendedsoilExamplesofstormwaterLIDsPermeable/porouspavementLIDPracticesHydrologyMicro-andSmallScalesDistributedPlacementDistributedStormwaterFeaturesRegionalTraditionalTechniquesDistributingStormwaterControlsClosetoRunoffSourcesAvery“traditional”detentionpondpicturesentbyJonJonesonApril1,2013[Notveryprettyandcouldbedangerous]ProblemswithTraditionalStormwaterManagementPractices•Norunoffvolumereduction,onlycontrolflowrateandlimitedwaterquality;•Noteffectiveatthewatershedlevel,putstressonfirstandsecondorderstreams.Source:PAStormwaterManagementManualKeyObjectives•Reducing“runoffcoefficient”–the“C”inQ=CIA–orthe“CN”intheCurveNumberMethod.RunoffVolumeandalsothePeakFlowRate•Increasingthe“TravelTime”--Delayingthearrivalofpeakflow•Increasingthe“initiallosses”,e.g.,depressionstorage,interceptionandevapotranspirationorET,therebyreducingtherunoffvolume.Q(Discharge)T(Time)DevelopedCondition,ConventionalCN(HigherPeak,MoreVolume,andEarlierPeakTime)ExistingConditionIAQTDevelopedCondition,withConventionalCNandControlsExistingAdditionalRunoffVolumeDevelopedExistingPeakRunoffRateGreenInfrastructure/LIDBeneficialFunctions•Reduceflooding•Improvewaterquality•Enhancegroundwaterrecharge•Reducestormwaterandcombinedsewersystemexpend