LEED Standards and Stormwater ManagementLow Impact Development

Yizhou Wang

Presentation Outline

• ConceptandHarmofStormwater

• LowImpactDevelopment

• LeadershipinEnergyandEnvironmentalDesign(LEED)

NewConstructionandMajorRenovation(NC)

Existing Buildings: Operations and Maintenance(BO&M)

NeighborhoodDevelopment(ND)

• PotentialImprovementofLEED

• ComparisonwithOtherSystems

EarthCraftCertificationSystem

EPA Guidance

• ApplicationofLEEDonRichmond,VA

ConceptandHarmsofStormwater

Waterthatoriginatesduringsharpprecipitation events and snowmelt

• Flowsdirectlyintosurfacewaterways

• Channeledintostormsewers,eventuallydischargetosurfacewaters

Concept:

Harms:

• Largevolumeandsharptimingoftherunoffwater

floodcontrolwatersupplyerosion

• Generationandtransmittionofcontaminants

waterpollutionhealthcarecrisisdrinkingwatershortage

Low Impact Development

Adesignstrategythatcreatesafunctionallyequivalenthydrologicsitedesignwiththe

goalofmaintainingorreplicatingthepre-developmenthydrologicregime, primarily

to counterhuman-inducedchangestotheenvironment.

LID:

Five Basic Steps:

1. Conservation

2. Minimization

3. PredevelopmentTimeofConcentration

4. Redevelopmentcurveandrunoffvolume

5. Pollutionprevention

LeadershipinEnergyandEnvironmentalDesignAvoluntary,consensus-based,market-drivenprogramthatprovidesthird-partyverificationofgreenbuildings.

SystemStructure:

LEEDSystemandLID

Tolimitdisruptionofnaturalhydrologybyreducingimperviouscover,increasingon-siteinfiltration,reducingoreliminatingpollutionfromstormwaterrunoffandeliminatingcontaminants.

NewConstruction:SiteSelection(SS)Credit6.1

1.SiteswithExistingImperviousness50%orLess• Implementastormwatermanagementplanthatpreventsthepostdevelopmentpeakdischargerateandquantityfromexceedingthepredevelopmentpeakdischargerateandquantityforthe1-and2-year24-hourdesign storms Or• Implement a stormwatermanagement plan that protects receiving stream channels from excessiveerosion.Thestormwatermanagementplanmust includestreamchannelprotectionandquantitycontrolstrategies2.SiteswithExistingImperviousnessGreaterThan50%• Implementastormwatermanagementplanthatresultsina25%decreaseinthevolumeofstormwaterrunofffromthe2-year24-hourdesignstorm.

• Designtheprojectsitetomaintain natural stormwater flowsbypromotinginfiltration.Specifyvegetated roofs,pervious pavingandothermeasures tominimize impervioussurfaces.Reusestormwater fornon-potableusessuchaslandscapeirrigation,toiletandurinalflushing,andcustodialuses.

Requirement:

PotentialTechnologies&Strategies:

LEEDSystemandLIDNewConstruction:SiteSelection(SS)Credit6.2

Tolimitdisruptionandpollutionofnaturalwaterflowsbymanagingstormwaterrunoff.

Implementastormwatermanagementplanthatreducesimperviouscover,promotesinfiltrationandcapturesandtreatsthestormwaterrunofffrom90%oftheaverageannualrainfall1usingacceptablebestmanagementpractices(BMPs). BMPsusedtotreatrunoffmustbecapableofremoving80%oftheaverageannualpostdevelopmenttotalsuspendedsolids(TSS)loadbasedonexistingmonitoringreports.BMPsareconsideredtomeetthesecriteriaif:• Theyaredesignedinaccordancewithstandardsandspecificationsfromastateorlocalprogramthathasadoptedtheseperformancestandards.Or• Thereexistsinfieldperformancemonitoringdatademonstratingcompliancewiththecriteria.Datamustconformtoacceptedprotocol(e.g.,TechnologyAcceptanceReciprocityPartnership[TARP],WashingtonStateDepartmentofEcology)forBMPmonitoring

• Use alternative surfaces (e.g., vegetated roofs, pervious pavement, grid pavers) and nonstructural techniques(e.g.,raingardens,vegetatedswales,disconnectionofimperviousness,rainwaterrecycling)toreduceimperviousnessandpromoteinfiltrationandtherebyreducepollutantloadings• Usesustainabledesignstrategies(e.g.,low-impactdevelopment,environmentallysensitivedesign)tocreate integratednaturalandmechanicaltreatmentsystemssuchasconstructedwetlands,vegetatedfiltersandopenchannelstotreatstormwaterrunoff

Requirement:

PotentialTechnologies&Strategies:

LEEDSystemandLIDNewConstruction:WaterEfficiency(WE)Credit1

Tolimitoreliminatetheuseofpotablewaterorothernaturalsurfaceorsubsurfacewaterresourcesavailableonorneartheprojectsiteforlandscapeirrigation.

Requirement:

1.Reduceby50%(2points) Reducepotablewaterconsumptionforirrigationby50%fromacalculatedmidsummerbaselinecase.Reductionsmustbeattributedtoanycombinationofthefollowingitems:

•Plant species,density and microclimatefactor•Irrigationefficiency•Useofcaptured rainwater •Useofrecycledwastewater •Useofwatertreatedandconveyedbyapublicagencyspecificallyfornonpotableuses Groundwater seepage that is pumped away from the immediate vicinity of building slabs andfoundationsmaybeusedforlandscapeirrigationtomeettheintentofthiscredit.However,theprojectteammustdemonstratethatdoingsodoesnotaffectsitestormwatermanagementsystems

2.NoPotableWaterUseorIrrigation(4points)MeettherequirementsforOption1.And• Useonlycapturedrainwater,recycledwastewater,recycledgraywaterorwatertreatedandconveyedbyapublicagencyspecificallyfornonpotableusesforirrigation.Or

• Installlandscapingthatdoesnotrequirepermanentirrigationsystems.Temporaryirrigationsystems

usedforplantestablishmentareallowedonlyifremovedwithin1yearofinstallation.

PotentialTechnologies&Strategies:

• Performasoil/climateanalysistodetermineappropriateplantmaterialanddesignthelandscapewithnative.Or• Adaptedplantstoreduceoreliminateirrigationrequirements.Whereirrigationisrequired,usehigh-efficiencyequipmentand/orclimate-basedcontrollers.

LEEDSystemandLIDNeighborhoodDevelopment:GreenInfrastructure/Building(GIB)Credit8

To reduce pollution and hydrologic instability from stormwater, reduce flooding, promote aquiferrecharge,andimprovewaterqualitybyemulatingnaturalhydrologicconditions

Requirement:

Implementacomprehensivestormwatermanagementplanfortheprojectthatretainson-site,throughinfiltration, evapotranspiration, and/or reuse, the rainfall volumes listed in Table 1. Rainfall volume isbasedontheproject’sdevelopmentfootprint,anyotherareasthathavebeengradedsoastobeeffectivelyimpervious,andanypollutiongeneratingpervioussurfaces,suchaslandscaping,thatwillreceivetreatmentsoffertilizersorpesticides.

Thepercentilerainfallevent(Table1)isthetotalrainfallonagivendayintherecordthatisgreaterthanorequaltoXpercentofallrainfalleventsovera20-to40+-yearperiod.

Table1.pointsforretainingstormwateron-site

Projectsthatearnatleast2pointsunderthiscreditmayearn1additionalpointbymeetingoneofthefollowingsitecharacteristics:• Theprojectislocatedonapreviouslydevelopedsite(1point).• TheprojectislocatedonasitethatmeetsthedefinitionofbrownfieldinSLLCredit2,BrownfieldsRedevelopment(1point).• Theprojectisdesignedtobetransitreadybyachievingthefollowing(1point): Atleast2pointsunderNPDCredit1,WalkableStreets Atleast2pointsunderNPDCredit2,CompactDevelopment Atleast2pointsunderNPDCredit3,Mixed-UseNeighborhoodCenters

SelectBMPsfromtheWashingtonStateDepartmentofEcology’sStormwatermanagementManualforWesternWashington,VolumeV,RunoffTreatment(2005edition),orlocallyapprovedequivalent,whicheverismorestringent.IftheBMPsarecomparableinstringency,chooseBMPsthataremostappropriatetotheprojectsiteandregion.BMPsmustalsocomplywithallfederal,state,andlocalregulations.

Forstormwaterreusesystemsnotonacombinedstormwaterandsewersystem,thetotalwaterreusedforindoorusemustnotexceed90%oftheaverageannualrainfall.

StormwaterBMPs(exceptcisterns)mustbedesignedtodraindownwithin72hours.

LEEDSystemandLIDExistingBuildings:Operation&Maintenance(LEEDBO&M):SustainableSite(SS)Credit6

TolimitthedisruptionofnaturalhydrologybythebuildingandgroundsRequirement:

During theperformanceperiod, implementa stormwatermanagementplan that infiltrates, collects andreuses runoff or evapotranspirates runn off from at least 15% of the precipitation falling on the wholeproject siteboth foranaverageweatheryearand for the two-year,24-hourdesign storm. Implementanannual inspectionprogramof all stormwatermanagement facilities ro confirm continuedperformance.Maintain documentation of inspection, including identification of areas of erosion,maintenanceneeds,andrepairs.Performallroutinerequiredmaintenance,necessaryrepairsorstabilizationwithin60daysofinspection.

PotentialTechnologies&Strategies:

Collectandreusestormwaterfornon-portableusessuchaslandscapeirrigation,toiletandurinalflushingand custodial uses. During facility or site alterations or additions, specify the use alternative surfaces(e.g.,vegetatedroofs,perviouspavementorgridpavers)andnonstructuraltechniques(e.g.,raingardens,vegetatedswales,disconnectionofimperviousness,rainwaterrecycling)toimproveperviousness,therebyrestoring or maintaining natural stormwater flows. Incorporate stormwater management facilities intoroutinepreventiveandcorrectivemaintenanceprograms.

PotentialImprovementofLEED

• LEEDshouldbemorepregressiveonquantitativerequirement:

“Implementastormwatermanagementplanthatpreventsthepostdevelopmentpeakdischargerateandquantityfromexceedingthepredevelopmentpeakdischargerateandquantityforthe1-and2-year24-hourdesignstorms”-------LEEDNC:SSCredit6.1

• LEEDshouldcollaboratemoreintenselywiththewholerelateddomains:

E.g.,Landscapedesign,Energy-relateddevelopment,etc.

• LEEDshoulddevelopdeepervisioninresolvingstormwaterfromrootcausesandaregional perspective E.g.,Cumulativeeffectsofstormwater,Watersheddecaying,Faililnginfrastructure,etc.

• LEEDshouldextendmoreactivelyintothepublicareawithmoreinteractionwiththemunicipalpowerandpublicparticipation E.g.,Publicinfrastructureupgrading,Sweagepipesmaintenance,Publiceducation/publication,etc.

ComparisonwithotherSystems

LEED EarthCraft EPARegulationsUSGreenBuildingCouncil(USGBC)

GreaterAtlantaHomeBuildersAssociationandSouthface

EnergyInstitute

UnitedStatesEnvironmentalProtectionAgencyAgencies

Structure

NC/ND/Homes/CommercialInterior/

Homes/Schools/ExistingBuildings(Operation&Maintenance)/Core&

Shelldevelopment/Retail

House/LigthCommercial/Renovation/Multifamily/

Communities

ClearWaterAct/Section438ofEnergyIndependenceandSecurityAct,etc.

Weakness

StrengthHighrecognition

ComprehensivesystemPrecisedefinition,ProfoundvisionStrongenfrocement,WideRangeLocal and regional cooperation

InterdisciplinaryEffortEnergy-inclined

InterdisciplinaryEffortEnergy/ReuseProfoundvision

CommercialStrategy

StringencyLocal and regional cooperation

Definiterequirement

Comprehensivesystem

ApplicationofLEEDonRichmond,VAProblemsHinderingStormwaterManagement

ofRichmond:

• NegativeinfluenceoftheentireChesapeake

Baywatershed

• Outdateddrainagepipesanderosionofur-

banproperty

• Designersanddevelopersvision

ApplicationofLEED:

• MoreemphasisandcreditshouldbeplacedtosolvetheproblemofthepublicutilitiesE.g.,outdateddrainagepipes,dirtyanddisrepairedstreetsanddilapidatedlandscape• Preservingandrehabiliatingtheentirewatershed• Instructdevelopers,designersandengineerstoproceedfromthebigpicturetoresolvethedeeply-rootedstormwaterproblems