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TECHNICALINFORMATIONREPORTforVUECRESTESTATES&VUECRESTIISHORTPLAT4800BlockofSmithersAvenueSinRenton,WashingtonAUG31ZOIbcivç’:.DRSProjectNo.12102RentonFileNo.LUAI3-000642&LUAI5-000026U15007217&U15007232Owner/ApplicantHarbourHomes,LLC1441North34thStreet,Suite200Seattle,WA98103ReportPreparedbymMD.R.STRONGConsultingEngineers,Inc.6207thAvenueKirklandWA98033(425)827-3063ReportIssueDateAugust25,2016/2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPageofiiiCityofRentonVuecrestEstates&VuecrestIIShortPlat TECHNICALINFORMATIONREPORTVUECRESTESTATES&VUECRESTIISHORTPLATTABLEOFCONTENTSSECTIONIProjectOverviewIPredevelopedSiteConditionsIDevelopedSiteConditionsINaturalDrainageSystemFunctions2SECTIONII18ConditionsandRequirementsSummary18SECTIONIII20Off-SiteAnalysis20SECTIONIV21FlowControlandWaterQualityFacilityAnalysisandDesign21ExistingSiteHydrology(PartA)21Pre-developedHourlylimeStepModelingInput22Pre-developedHourlyTimeStepModelingOutput:22DevelopedSiteHydrology(PartB)24DevelopedSiteAreaHydrology24DevelopedHourlyTimeStepModelingInput’26DevelopedHourlyTimeStepModelingOutput26BYPASSHourlyTimeStepModelingInput’27BYPASSHourlyTimeStepModelingOutput’27PerformanceStandards(PartC)29FlowControlSystem(PartD)29FlowControlBMPSelection29FlowControlFacilityDesignOutput30WaterQualityTreatmentSystem(PartE)37SECTIONV39ConveyanceSystemAnalysisandDesign39SECTIONVI51SpecialReportsandStudies51SECTIONVII52OtherPermits,VariancesandAdjustments52©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPageiiofIITechnicalInformationReportCityofRenton SECTIONVIII.53ESCPlanAnalysisandDesign(PartA)53swPPsPlanDesign(PartB)54SECTIONIX55BondQuantities,FacilitySummaries,andDeclarationofCovenant55StormwaterFacilitySummarySheet56SECTIONX58OperationsandMaintenanceManual58APPENDICES61Appendix“A”OffsiteAnalysis’62Appendix“B”CSWPPP63Appendix“C”BondQuantityWorksheet64ListofFiguresFigure1TlRWorksheet3Figure2VicinityMap13Figure3DrainageBasins,Subbasins,andSiteCharacteristics14Figure4Soils15Figure5PredevelopmentAreaMap23Figure6PostDevelopmentAreaMap28Figure7Detention&WaterQualityFacilityDetails38Figure8BackwaterAnalysisMap42©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPageiiiofiiiTechnicalInformationReportCityofRenton SECTIONIPROJECTOVERVIEWTheVuecrestEstatessubdivision(VC)proposestosubdivide6.05acresofthe9.31acreparcel(parcelnumber3123059048)into20detachedsingle-familyresidentialhomes,pertheCityofRenton’ssubdivisionprocess.TheVuecrestIIShortPlat(VCII)proposestosubdivide2.45acres(parcelnumber3223059097)intoeightsingle-familyresidentialhomes,pertheCityofRenton’ssubdivisionprocess.ThetwosubdivisionswillshareasinglestormfacilityandwillconnectthroughanextensionofSmithersAvenueSouth.Therefore,forpurposesofthisreport,thetwosubdivisionswillbeconsideredasingleproject(Project).TheProjectwillmeetthedrainagerequirementsofthe2009KingCountySurfaceWaterDesignManual(Manual),asadoptedbytheCity.PREDEVELOPEDSITECONDITIONSTotalexistingareaisapproximately512,084s.f.(11.76ac).TheVCparceliscurrentlyundevelopedandtheVCIIparcelcontainsanexistinghousewhichfrontsonMainAvenueS.TheVCparcelissituatedwithaportionatoparidgeattachedtoasteephillsidedischargingrunoffintotheBlackRiversubbasin.ThereisaCategoryIllwetlandalongtheeasternpropertylineofVCaswellasachannellocatednearthesouthernportionofvCclassifiedasaClass4streamwithanassociatedwetland.TheClass4streamandwetlandextendupstreamthroughthenorthwestcornerofVCll.AportionofProjectrunofffollowsachannelanddischargesnearthesouthwestcornerofVCandeventuallytotheconveyancesysteminTalbotRoadSouth.TheremaindersheetflowsdownthehillsideandthroughtheCampenSpringsproperty,andthenproceedstoaconveyancesystemwithinTalbotRoadS.TheProjectisconsideredtobewithinoneThresholdDischargeArea(TDA).Forthepurposeofhydrologiccalculations,theentiredevelopableSiteismodeledastillforest.DEVELOPEDSITECONDITIONSTheapplicanthasgainedapprovaltocreate28lots(VC—20lots,VCII—8lots)withlotsizesrangingfromapproximately4,500s.f.to17,046s.f.The28single-familyresidencescombinedwiththeirdrivewayswillcreateapproximately95,800s.f.(3,600sftobefullydispersed)ofimperviousarea.Themajorityoftheproposedrightofwaywillbeimprovedwith26feetofpavement,verticalcurb,gutter,eight-footplanterstripandfive-footsidewalks.Portionsoftherightofwaythroughthesensitiveareaswillbeimprovedwith22feetofpavement,curbandgutterandafive-footsidewalkononesidewhiletheportionfrontingLotsIthrough7ofVCIIwillbeimprovedwith26feetofpavement,curbandgutter,eightfootplanterandfive-footsidewalkononeside(modifiedCityofRentonHalfStreetstandard).Twostubroadsareproposedtoservefourlotseach;theywillbecomprisedof20feetofpavement.Theimprovementsfromright-ofwaysandstubroadswilladdapproximately63,750s.f.ofimpervioussurface.Thetotaldeveloped/disturbedareais259,475s.f.ofwhichI59,550isimpervious©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage1TechnicalinformationReportCityofRenton (155,950tothedetentionfacilitydueto3,600sf.offulldispersion).Theremainderofthedisturbedarea(99,925s.f.)willconsistoflandscapingandlawns.TheProjectisrequiredtoprovideBasicWaterQualitytreatmentandLevel3FlowControl,perthe2009KCSWDM(Manual).Allsurfacewaterrunofffromimpervioussurfaceswillbecollectedandconveyedtoastormdetention/waterqualityvaultlocatedinTract“A”ofVC.NATURALDRAINAGESYSTEMFUNCTIONSTheSitetopographyslopesfromtheeastofthesitetothewest.Thevegetationconsistsoftreesandmoderateunderbrush.AportionofSiterunofftravelswesterlyandflowsofftheSite,throughavegetatedchannelnearS50thStreet,andeventuallyintoaconveyancesystemwithinTalbotRoadS.RunofffromtheremainderoftheSiteareasheetflowsdownthesteepsleepandintotheconveyancesystemwithintheCampenSpringsCondominiumdevelopmentbeforeenteringtheconveyancesystemwithinTalbotRoadS.,therefore,encompassingtheProjectinoneTDA.AreviewoftheSOSsoilsmapforthearea(seeFigure4,Soils)indicatesAlderwoodgravellysandyloamwith6to15percentslopes(AgO)and15to30percentslopes(AgD).PertheManual,thissoiltypeisclassifiedas“Till”material.TheSOSSoilseriesdescriptionsfollowFigure4.Inevaluatingtheupstreamarea,wereviewedKingCountyIMAPaerialtopographyandimageryandconductedfieldreconnaissance.WeconcludedthattheupstreamareadoesnotdraintothedevelopableareaoftheSite.AsmallportionofthepropertieseastandnorthoftheProjectappeartodraininaneasterlymannertowards102ndAvenueSE.TheremainderofthosepropertiesappearstodraintowardstheSite,howeverisinterceptedbytheonsitesensitiveareasanddoesnotreachthedevelopableportionsoftheProject.PropertiestothenorthdrainwesterlywithnoimpacttotheSite.PropertiestothesouthdrainssoutherlyawayfromtheSite.©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&vuecrestIIShortPlatPage2TechnicalInformationReportcityofRenton FIGURE1TIRWORKSHEETTECHNiCALINFORMATIONREPORT(T1R)WORKSHEET-VCPartIPROJECTOWNERANDPROJECTENGiNEERProjectOwner:HarbourHomes,LLCPhone:(206)315-8130Address:1441N34thStreet,Suite200Seattle,WA98103ProjectEngineer:MaherA.Joudi,P.E.Company:D.R.STRONGConsultingEngineersInc.Phone:(425)827-3063Part3TYPEOFPERMITAPPLICATIONLanduseServicesSubdivisionIShortSubdivisionIUPDE:1BuildingServices:M/FICommercialISFRClearingandGradingElRight-of-Wayi:iOther:Part2PROJECTLOCATIONANDDESCRIPTIONProjectName:VuecrestEstatesRentonPermit#:LUAI3-000642Location:Township:23NorthRange:05EastSection:31SiteAddress:SmithersAveS/S47thStreetPart4OTHERREVIEWSANDPERMITSDFWHPAElShorelineMngmtLICOE404StructuralUDOEDamSafetyRockery/VaultE:jFEMAFloodplainLIESASection7COEWetlandsEOther:Part5PLANANDREPORTINFORMATIONTechnicalInformationReportSiteImprovementPlan(Engr.Plans)TypeofDrainageReviewITargetedIType(circleone):IModifiedI(circle):LargeSiteSmallSiteDate(includerevisionSeptember17,2015Date(includerevisionSeptember17,2015dates):dates):DateofFinal:DateofFinal:Part6ADJUSTMENTAPPROVALSType(circleone):StandardIComplexIPreapplicationIExperimentalIBlanketDescription:(includeconditionsinTIRSection2)DateofApproval:VuecrestEstates&Vuecrest1ShortPlat©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage3CityofRenton Part7MONITORINGREQUIREMENTSMonitoringRequired:Yes!Describe:StartDate:CompletionDatePart8SITECOMMUNITYANDDRAINAGEBASINCommunityPlan:SoosCreekSpecialDistrictOverlays:N/ADrainageBasin:BlackRiverStormwaterRequirements:Level3FlowControl,BasicWQTreatmentMenuPart9ONSITEANDADJACENTSENSITIVEAREASRiver!StreamUnnamedstreamSteepSlopetoremainundisturbedLILakeLIErosionHazard_____________________WetlandsIsolated&wetlandnearstreamflLandslideHazard____________________ElClosedDepressionElCoalMineHazard___________________ElFloodplainLISeismicHazard_____________________EOtherEHabitatProtection____________________PartlOSOILSSoilTypeSlopesErosionPotentialAgC6-15%ModerateAgD15-30%SevereLIHighGroundwaterTableElSoleSourceAquiferotherVerylowinfiltrationrateElSeeps/SpringsElAdditionalSheetsAttachedVuecrestEstates&VuecrestIIShortPlat©2016D.R.STRONGconsultingEngineersInc.TechnicalInformationReportPage4cityofRenton PartIIDRAINAGEDESIGNLIMITATIONSREFERENCELIMITATIONISITECONSTRAINTElCore2—OffsiteAnalysisLISensitiveICriticalAreaSensitiveareaspresentonSiteLISEPAElOtherLIAdditionalSheetAttachedPart12TIRSUMMARYSHEET(provideoneTIRSummarySheetperThresholdDischargeArea)ThresholdDischargeArea:SingleTDA,unnamed(nameordescription)CoreRequirements(all8apply)DischargeofNaturalLocationyesNumberofNaturalDischargeLocations:IOffsiteAnalysisLevel:III3dated:09/17115FlowControlLevel:112IorExemptionNumber(md.facilitysummarysheetSmallSiteBMPSRestrictedFootprintIFullDisp.ConveyanceSystemSpillcontainmentlocatedat:DetentionfacilitiesErosionandSedimentControlESCSiteSupervisor:T!BIDContactPhone:TIB/DAfterHoursPhone:TIBIDMaintenanceandOperationResponsibility:PrivateIPublicIfPrivate,MaintenanceLogRequired:YesINoFinancialGuaranteesandProvided:YesINoLiabilityWaterQualityType:BasicISensLakeIEnhancedBasicIBog(includefacilitysummarysheet)orexemptionNo.LandscapeManagementPlan:YesINoSpecialRequirements(asapplicable)AreaSpecificDrainageType:CDA1SDOIMDPIBPILMPISharedINoneRequirementsName:Floodplain/FloodwayDelineationType:MajorIMinorIExemption/None100-yearBaseFloodElevation(orrange):Datum:FloodProtectionFacilitiesDescribe:N/ASourceControlDescribeLanduse:(comm.Iindustriallanduse)Describeanystructuralcontrols:OilControlHigh-useSite:YesITreatmentBMP:MaintenanceAgreement:YesINo©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage5TechnicalInformationReportcityofRenton withwhom?OtherDrainageStructuresDescribe:AproposeddetentionvaultlocatedinTractAofVCwillservebothsubdivisions.Part13EROSIONANDSEDIMENTCONTROLREQUIREMENTSMINIMUMESCREQUIREMENTSMINIMUMESCREQUIREMENTSDURINGCONSTRUCTIONAFTERCONSTRUCTIONClearingLimitsStabilizeExposedSurfacesRemoveandRestoreTemporaryESCCoverMeasuresFacilitiesPerimeterProtectionCleanandRemoveAllSiltandTrafficAreaStabilizationDebris,EnsureOperationsofPermanentFacilitiesSedimentRetentionFlagLimitsofSAOandopenspaceSurfaceWaterCollectionPreservationareasLIOtherDewateringControlDustcontrolFlowControlPart14STORMWATERFACILITYDESCRIPTIONS(Note:IncludeFacilitySummaryandSketchFlowControlType/DescriptionWaterQualityType/DescriptionDetentionVaultElBiofiltrationEInfiltrationWetpoolWetvaultLIRegionalElMediaFiltrationFacilitySharedFacilityVaultElOilControlFlowControlRestrictedFootprintLISpillControlBMPsFullDispersionFlowControlSeeflowcontrolLIOtherBMPsLIOtherVuecrestEstates&VuecrestIIShortPlatPage6cityofRenton©2016D.R.STRONGconsultingEngineersInc.TechnicalInformationReport ©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportSianed/DatePage7CityofRentonPart15EASEMENTS/TRACTSDrainageEasementLICovenantElNativeGrowthProteCtionCovenantElTractLIOther:Part16STRUCTURALANALYSISCastinPlaceVaultDRetainingWallDRockery>4’HighDStructuralonSteepSlopeElOther:Part13SIGNATUREOFPROFESSIONALENGINEERIoracivilengineerundermysupervisionhavevisitedthesite.Actualsiteconditionsasobservedwereincorporatedintothisworksheetandtheattachments.Tothebestofmyknow,edetheinformationprovidedhereisaccurate.II4V-<LZ-‘,1Ub.lVuecrestEstates&VuecrestIIShortPlat TECHNICALINFORMATIONREPORT(TIR)WORKSHEET-VCIIPart1PROJECTOWNERANDPROJECTENGINEERProjectOwner:HarbourHomes,LLCPhone:(206)315-8130Address:1441N34thStreet,Suite200Seattle,WA98103ProjectEngineer:MaherA.Joudi,P.E.Company:D.R.STRONGConsultingEngineersInc.Phone:(425)827-3063Part3TYPEOFPERMITAPPLiCATIONLanduseServicesSubdivisionIShortSubdivisionIUPDLIBuildingServices:M/FICommercialISFRClearingandGradingLIRight-of-WayLIOther:Part2PROJECTLOCATIONANDDESCRIPTIONProjectName:VuecrestIIShortPlatRentonPermit#:LUAI5-000026Location:Township:23NorthRange:05EastSection:31SiteAddress:4903MainAveS.Part4OTHERREVIEWSANDPERMITSDEWHPAEShorelineMngmtElCOE404StructuralLIDOEDamSafetyRockery/WallLIFEMAFloodplainüESASection7COEWetlandsLiOther:Part5PLANANDREPORTINFORMATIONTechnicalInformationReportSiteImprovementPlan(Engr.Plans)TypeofDrainageReviewITargetedIType(circleone):j/ModifiedI(circle):LargeSiteSmallSiteDate(includerevisionSeptember17,2015Date(includerevisionSeptember17,2015dates):dates):DateofFinal:DateofFinal:Part6ADJUSTMENTAPPROVALSType(circleone):StandardIComplexIPreapplicationIExperimentalIBlanketDescription:(includeconditionsinTIRSection2)DateofApproval:©2016D.R.STRONGconsultingEngineersInc.TechnicalInformationReportPage8cityofRentonVuecrestEstates&VuecrestIIShortPlat Part7MONITORINGREQUIREMENTSMonitoringRequited:Yes!Describe:StartDate:CompletionDatePart8SITECOMMUNITYANDDRAINAGEBASINCommunityPlan:SoosCreekSpecialDistrictOverlays:N/ADrainageBasin:BlackRiverStormwaterRequirements:Level3FlowControl,BasicWQTreatmentMenuPart9ONSITEANDADJACENTSENSITIVEAREASRiver/StreamUnnamedstreamLISteepSlope________________________LILakeLIErosionHazard_____________________WetlandswetlandneatstreamElLandslideHazard____________________LIClosedDepressionElCoalMineHazard___________________LIFloodplainLISeismicHazard_____________________ElOtherElHabitatProtection____________________PartlOSOILSSoilTypeSlopesErosionPotentialAgC6-15%ModerateElHighGroundwaterTableElSoleSourceAquiferotherVerylowinfiltrationrateflSeeps/SpringsElAdditionalSheetsAttached©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage9TechnicalInformationReportcityofRenton VuecrestEstates&VuecrestIiShortPlatREFERENCELICore2—OffsiteAnalysisLISensitiveICriticalAreaElSEPAElOtherLILIMITATIONISITECONSTRAINTPartIIDRAINAGEDESIGNLIMITATIONSSensitiveareaspresentonSiteAdditionalSheetAttachedPart12TIRSUMMARYSHEET(provideoneTIRSummarySheetperThresholdDischargeArea)ThresholdDischargeArea:SingleTDA,unnamed(nameordescription)CoreRequirements(all8apply)DischargeofNaturalLocationyNumberofNaturalDischargeLocations:IOffsiteAnalysisLevel:j12I3dated:01/15/15FlowControlLevel:112I3orExemptionNumber(md.facilitysummarysheetSmallSiteBMPSRestrictedFootprint/FullDisp.ConveyanceSystemSpillcontainmentlocatedat:DetentionfacilitiesErosionandSedimentControlESCSiteSupervisor:T/B/DContactPhone:T/B/DAfterHoursPhone:TIB/DMaintenanceandOperationResponsibility:PrivateIPublicIfPrivate,MaintenanceLogRequired:YesINoFinancialGuaranteesandProvided:YesINoLiabilityWaterQualityType:BasicISensLakeIEnhancedBasicIBog(includefacilitysummarysheet)orexemptionNo.LandscapeManagementPlan:YesISpecialRequirements(asapplicable)AreaSpecificDrainageType:CDAISDOIMDPIBPILMPISharedINoneRequirementsName:Floodplain/FloodwayDelineationType:Major/MinorIExemptionINone100-yearBaseFloodElevation(orrange):Datum:FloodProtectionFacilitiesDescribe:N/ASourceControlDescribeLanduse:(comm./industriallanduse)Describeanystructuralcontrols:OilControlHigh-useSite:Yes1fTreatmentBMP:MaintenanceAgreement:Yes/©2016D.R.STRONGconsultingEngineersInc.TechnicalInformationReportPage10cityofRenton withwhom?OtherDrainageStructuresDescribe:AproposeddetentionvaultlocatedinTractAofVCwillservebothsubdivisions.Part13EROSIONANDSEDIMENTCONTROLREQUIREMENTSMINIMUMESCREQUIREMENTSMINIMUMESCREQUIREMENTSDURINGCONSTRUCTIONAFTERCONSTRUCTIONClearingLimitsStabilizeExposedSurfacesRemoveandRestoreTemporaryESCCoverMeasuresFacilitiesPerimeterProtectionCleanandRemoveAllSiltandTrafficAreaStabilizationDebris,EnsureOperationsofPermanentFacilitiesSedimentRetentionFlagLimitsofSAOandopenspaceSurfaceWaterCollectionPreservationareasLIOtherDewateringControlDustcontrolFlowControlPart14STORMWATERFACILITYDESCRIPTIONS(Note:IncludeFacilitySummaryandSketchFlowControlType/DescriptionWaterQualityType/DescriptionDetentionVaultElBiofiltrationElInfiltrationWetpoolWetvaultRegionalLIMediaFiltrationFacilitySharedFacilityVaultLIOilControlFlowControlRestrictedFootprintLISpillControlBMPsFullDispersionFlowControlSeeflowcontrolLIOtherBMPsLIOtherVuecrestEstates&VuecrestIIShortPlat©2016D.R.STRONGconsultingEngineersInc.TechnicalInformationReportPage11cityofRenton Part13SIGNATUREOFPROFESSIONALENGINEERIoracivilengineerundermysupervisionhavevisitedthesite.Actualsiteconditionsasobservedwereincorporatedintothisworksheetandtheattachments.TothebestofmyknowdQetheinformationprovidedhereisaccurate.VuecrestEstates&VuecrestIIShortPlatPa15EASEMENTS/TRACTSDrainageEasementDCovenantLINativeGrowthProtectionCovenantLITractLIOther:Part16STRUCTURALANALYSISCastinPlaceVaultDRetainingWallLIRockery>4’HighDStructuralonSteepSlopeLIOther:©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage12CityofRenton FIGURE2VICINITYMAPVuecrestEstates&VuecrestIIShortPlatPage13CityofRenton-•“j:Tu1vi1ac‘IiviL--\.titS::..,‘-Renton-Tnkwi)iI{efltOflKentt:tiiLw.,zz-”1I©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReport FIGURE3DRAINAGEBASINS,SUBBASINS,ANDSITECHARACTERISTICS©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage14TechnicalInformationReportCityofRenton -L — H ——-— VUECRESTESTATES &VUECRESTII SHORTPLAT RGLRE3:DRAINAGEB4SWS,SUBBASINS AND SITE CHAR4CTERIST!CS ©2016D.R.STRONGConsultingEngineersInc.Page15TechnicalInformationReportCityofRentonFIGURE4SOILSVuecrestEstates&VuecrestIIShortPlat AgC—Alderwoodgravellysandyloam,6to15percentslopesMapUnitSetting.Elevation:50to800feet.Meanannualprecipitation:25to60inches.Meanannualairtemperature:48to52degreesF.Frost-freeperiod:180to220daysMapUnitComposition.Alderwoodandsimilarsoils:95percent.Minorcomponents:5percentDescriptionofAlderwoodSetting.Landform:Moraines,tillplainsSParentmaterial:BasaltillwithsomevolcanicashPropertiesandqualities.Slope:6to15percent.Depthtorestrictivefeature:24to40inchestodensicmaterial.Drainageclass:Moderatelywelldrained.Capacityofthemostlimitinglayertotransmitwater(Ksat):Verylowtomoderatelylow(0.00toOO6in/hr).Depthtowatertable:About18to37inches.Frequencyofflooding:None.Frequencyofponding:None.Availablewatercapacity:Verylow(about2.5inches)Interpretivegroups.Farmlandclassification:Farmlandofstatewideimportance.Landcapability(nonirrigated):4s.HydrologicSoilGroup:BTypicalprofile.0to12inches:Gravellysandyloam.12to27inches:Verygravellysandyloam.27to60inches:VerygravellysandyloamMinorComponentsNorma.Percentofmapunit:1percent.Landform:DepressionsBellingham.Percentofmapunit:Ipercent.Landform:DepressionsSeattle.Percentofmapunit:Ipercent.Landlorm:DepressionsTukwila.Percentofmapunit:1percent.Landlorm:DepressionsShalcar.Percentofmapunit:1percent.Landform:DepressionsAgD—Alderwoodgravellysandyloam,15to30percentslopesMapUnitSetting.Elevation:50to800feet.Meanannualprecipitation:25to60inches©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage16TechnicalInformationReportCityofRenton Meanannualairtemperature:48to52degreesFFrost1reeperiod:180to220daysMapUnitCompositionAlderwoodandsimilarsoils:100percentDescriptionofAlderwoodSetting.Landform:Moraines,tillplains.Parentmaterial:BasaltillwithsomevolcanicashPropertiesandqualities.Slope:15to30percent.Depthtorestrictivefeature:24to40inchestodensicmaterial.Drainageclass:Moderatelywelldrained.Capacityofthemostlimitinglayertotransmitwater(Ksat):Verylowtomoderatelylow(0.00to0.06in/hr).Depthtowatertable:About18to37inches.Frequencyofflooding:None.Frequencyofponding:None.Availablewatercapacity:Verylow(about2.5inches)Interpretivegroups.Farmlandclassification:Farmlandofstatewideimportance.Landcapability(nonirrigated):4e.HydrologicSoilGroup:BTypicalprofile.0to12inches:GravellyashysandyloamS12to27inches:Verygravellysandyloam.27to60inches:Verygravellysandyloam©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage17TechnicalInformationReportcityofRenton SECTIONIICONDITIONSANDREQUIREMENTSSUMMARYTheProjectmustcomplywiththefollowingCoreandSpecialRequirements:.CR.#1—DischargeattheNaturalLocation:TheSitewilldischargeatitsnaturaldischargelocation..C.R.#2—OffsiteAnalysis:AnalysisisincludedinSectionIII.TheAnalysisdescribestheSite’srunoffpatternsindetail.ALevelTwoDownstreamAnalysiswasperformedontheCampenSpringsconveyancesystemintowhichtheProjectisdischarging.aCR.#3—FlowControl:TheprojectislocatedintheFlowControlDurationStandard,ForestedSiteConditions,area,howeverduetoconnectionthroughthedownstreamsystemwilladheretoLevel3FlowControlStandards.Adetentionvaultwillprovideflowcontrolasrequired.TheProjectisrequiredtomatchdurationsfor50%ofthetwo-yearpeakflowuptothefull50-yearpeakflow.Alsomatchdevelopedpeakdischargeratestopredevelopedpeakdischargeratesforthe2-year,I0-yearand100-yearreturnperiods(KCSWDM,Sec.I.2.)Furthermore,theProjectmustmeettheFlowControlBMPrequirementsasspecifiedinSection1.2.3.3oftheManual.TheProjectwillutilizethereducedimpervioussurfacecreditandfulldispersiontomeetthisrequirement.aC.R.#4—ConveyanceSystem:Newpipesystemsandditches/channelsarerequiredtobedesignedwithsufficientcapacitytoconveyandcontain(atminimum)the25-yearpeakflowwithaminimumof6inchesoffreeboardbetweenthedesignwatersurfaceandstructuregrate,assumingdevelopedconditionsforonsitetributaryareasandexistingconditionsforanyoffsitetributaryareas.Pipesystemstructuresandditches/channelsmayovertopforrunoffeventsthatexceedthe25-yeardesigncapacity,providedtheoverflowfromaI00-yearrunoffeventdoesnotcreateoraggravatea“severefloodingproblem”or“severeerosionproblem”asdefinedinC.R.#2.Anyoverflowoccurringonsiteforrunoffeventsuptoandincludingthe100-yeareventmustdischargeatthenaturallocationfortheprojectsite.Inresidentialsubdivisions,suchoverflowmustbecontainedwithinanonsitedrainageeasement,tract,covenantorpublicright-of-way.TheproposedconveyancesystemwasanalyzedusingtheKCBWprogram,andiscapableofconveyingthe100-yearpeakstormwithoutovertoppinganystructuresorchannels..C.R.#5—ErosionandSedimentControl:TheProjectprovidesthenineminimumESCmeasures..CR.#6—MaintenanceandOperations:MaintenanceoftheproposedstormdrainagefacilitieswillbetheresponsibilityoftheCity.AnOperationandMaintenanceManualisincludedinSectionX..C.R.#7—FinancialGuarantees:Priortocommencingconstruction,theApplicantmustpostadrainagefacilitiesrestorationandsitestabilizationfinancialguarantee.©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage18TechnicalInformationReportcityofRenton ForanyconstructedormodifieddrainagefacilitiestobemaintainedandoperatedbytheCity,theApplicantmust:1)Postadrainagedefectandmaintenancefinancialguaranteeforaperiodoftwoyears,and2)Maintainthedrainagefacilitiesduringthetwo-yearperiodfollowingpostingofthedrainagedefectandmaintenancefinancialguarantee..C.R.#8—WaterQuality:TheProjectislocatedintheBasicWaterQualityTreatmentarea.Thecombineddetention/waterqualityvaultwillaccommodatethisrequirement..S.R.#1—OtherAdoptedArea-SpecificRequirements:NotapplicableforthisProject..S.R.#2—Floodplain/FloodwayDelineation:NotapplicableforthisProject..S.R.#3—FloodProtectionFacilities:NotapplicableforthisProject..S.R.#4—SourceControl:NotapplicableforthisProject..S.R.#5—OilControl:NotapplicableforthisProject..S.R.#6—AquiferProtectionArea:NotapplicableforthisProject.©2016D.R.STRONGconsulungEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage19TechnicalInformationReportcityofRenton SECTIONIIIOFF-SITEANALYSISAnoffsiteLevelTwoDownstreamAnalysiswaspreparedbyDR.STRONGConsultingEngineersInc.andisincludedinAppendixA.AnoffsiteLevelOneDownstreamAnalysiswaspreparedbyBarghausenConsuttingEngineers,Inc.andisincludedinAppendixA.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage20TechnicalInformationReportCityofRenton SECTIONIVFLOWCONTROLANDWATERQUALITYFACILITYANALYSISANDDESIGNEXISTINGSITEHYDROLOGY(PARTA)KCRTSwasusedtomodelthepeakrunofffromtheSite.PerTable3.2.2.boftheManual,thesoiltypeismodeledas“Till”fortheAlderwoodgravellysandyloamSCSclassificationasshowninFigure4.Soils.TheentireProjectismodeledasForest.ResultsoftheKCRTSanalysisareincludedinthissection.Thetotaldisturbedareatobeincludedinthedetentioncalculationsis255,875s.f.(5.874acres);thisismodeledasTillForest.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage21TechnicalInformationReportCityofRenton PRE-DEVELOPEDHOURLYTIMESTEPMODELINGOUTPUT:FlowFrequencyAnalysisTimeSeriesFile:predev.tsfProjectLocation:Sea-Tac---AnnualFlowRatefCFS)0.3700.1000.2750.0100.1630.2840.2400.474ComputedFlowFrequencyAnalysis--Peaks--RankReturnProbfCFS)Period0.4741100.000.9900.370225.000.9600.284310.000.9000.27545.000.8000.24053.000.6670.16362.000.5000.10071.300.2310.01081.100.0910.43950.000.980©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage22CityofRentonPRE-DEVELOPEDHOURLYTIMESTEPMODELINGINPUT:LandcoverTiltForest(ac)TillGrass(ac)OutwashForest(ac)Impervious(ac)ScaleFactor:TimeStep:DataType:Projectlocation:TotalArea:5.8740.0000.0000.0001.00HourlyReducedSeatac5.874PeakFlowRates---RankTimeofPeak22/09/0118:0071/06/023:0042/28/033:0083/24/0420:0061/05/058:0031/18/0621:00511/24/064:0011/09/089:00PeaksVuecrestEstates&VuecrestIIShortPlat FIGURE5PREDEVELOPMENTAREAMAP©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage23TechnicalInformationReportCityofRenton •JdOO=HDNI[ooOO[0903-wooDIHdVdOF1Lc:NjHp DEVELOPEDSITEHYDROLOGY(PARTB)DEVELOPEDSITEAREAHYDROLOGYKCRTSwasusedtomodelthedevelopedpeakrunofffromtheSite.Thesoiltypesareunchangedfromthepre-developedconditions.TheportionsoftheSitewithintheproposedclearinglimitstributarytotheproposeddetentionvaultweremodeledas“TillGrass”and“Impervious”asappropriate.ThisareaisinclusiveofthefrontageimprovementsonMainAvenueSouth.ResultsoftheKCRTSanalysisareincludedinthissection.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&vuecrestIIShortPlatPage24TechnicalInformationReportCityofRenton )oeNPX4edeNuo!wwJuIIe!icdtIdJO4SII?9WS3flAU6U36WSODNOIIS09LOZtBOL£L900Vt8010V1801SPOiMOJOLvLOOZ66S1210T9OSStS11LO11DVNiJ1O1aootttvvivii0068s6pt000SGPL000t?3fJ96OVESLEGIS6S9tOCISSSzvGOES00GSSLOatOOSE000VGSSLSPtStS0SSSLI£9SOOES005951001OOS000559515965150E9SL99919005900999100100950005999199tV09991S£U9GOES009191001009900095191StS919091519asscossooLLSI001009900091191951919011.91915990095001591001009%00099591996919015919999900990099650010099000999689150691ocssstiijma-jijriidwIqeMojjSuuozAqdwisipuneavON1NoIiNaiiaoiioiSSVdA9PSJfl9S1VO1dL’NSII00091519SLSIZD10001995919959ODVLL0007996199961).DVSI00065919659199IDVUI9699OOSZ99190790919919SVCSEVDVNJ.SZ%IIIE8091t9699099%0099990190099900099Z9S9919709999UlISEZ099€0091150190099%0009IlLS9999990IlLS61stct06990099699090099966999659999%0965951990909910096910190099900099661110609691LI£10909960019990190099900099919191119099999109090991000191019009190009III9910900191619169099900959901900919000998991911909599#1966109190099911619009991666999911696909991II011106960000179900911611901911110001991011109990000691900999616%019119900069119999099%009199019009990009919911656909199011999099900006501900999000911619999990016160690999616106101019009990009199SILLS11501995IZI0690991909511019009150009999919959009195991669099995910tIll019009660009956106599III9861909909900161009190190099900091909190619LOS1909S196099%96090ISIS0190099900095599591699105559996650999996109195019009960009St69599119905dIgI6cc099919510919501900999000965095999579996509999909995199091050190099000096tt9596559100161t9I•9ij:iaijKiaw.99j99jX9telosi9iDi3jThs.dwjpanpadwt9MOj9U!UOZAqdw.i9i1s!pur.99iNOIINOJIG01107SSVdASpaqn9s5Jeav101dL’95UMOP)99J8 LandcoverTillForest(ac)TillGrass(ac)OutwashForest(ac)Impervious(ac)ScaleFactor:TimeStep:DataType:Projectlocation:TotalArea:0.0001.8770.0003.5801.00HourlyReducedSeatac5.457---AnnualFlowRate(CFS)1.030.8511.240.9271.111.101.352.09ComputedPeaks©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportFlowFrequencyAnalysis--Peaks--RankReturnProb(CFS)Period2.091100.000.9901.35225.000.9601.24310.000.9001.1145.000.8001.1053.000.6671.0362.000.5000.92771.300.2310.85181.100.0911.8450.000.980Page26CityofRentonDEVELOPEDHOURLYTIMESTEPMODELINGINPUT:DEVELOPEDHOURLYTIMESTEPMODELINGOUTPUT:FlowFrequencyAnalysisTimeSeriesFile:rdin.tsfProjectLocation:Sea-TacPeakFlowRates---RankTimeofPeak62/09/0181/05/0232/27/0378/26/04410/28/0451/18/06210/26/0611/09/082:0016:007:002:0016:0016:000:006:00VuecrestEstates&VuecrestIIShortPlat LandcoverTillForest(ac)TillGrass(ac)OutwashForest(ac)Impervious(ac)ScaleFactor:TimeStep:DataType:Projectlocation:TotalArea:0.0000.4170.0000.000I.00HourlyReducedSeatacr0.417---AnnualFlowRate(CFS)0.0370.0190.0470.0080.0200.0380.0340.088ComputedPeaks©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportFlowFrequencyAnalysis--Peaks--RankReturnProb(CFS)Period0.0881100.000.9900.047225.000.9600.038310.000.9000.03745.000.8000.03453.000.6670.02062.000.5000.01971.300.2310.00881.100.0910.07450.000.980Page27CityofRentonBYPASSHOURLYTIMESTEPMODELINGINPUT:BYPASSHOURLYTIMESTEPMODELINGOUTPUT:FlowFrequencyAnalysisTimeSeriesFile:bypass.tsfProjectLocation:Sea—TacPeakFlowRates---RankTimeofPeak42/09/0171/05/0222/27/0388/26/0461/05/0531/18/06511/24/0611/09/082:0016:007:002:008:0016:003:006:00VuecrestEstates&VuecrestIIShortPlat FIGURE6POSTDEVELOPMENTAREAMAP©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage28TechnicalInformationReportCityofRenton _zFRIGHTOfWAYAREALOTAREABrYASSr—iUND.’SR&EDLOTAREAIMPERROrIS:92200SFTILLGRASS:74702SfIMPERVIOUS:0I7LLCRASS:78759SFTILLFOREST8611SFDRAINAGERAFTIMPLRI1OUF2500SFJiLLCRASS:6392SFNDrn-i-iGRAPHICSCALE050100200t:1INCHIOOFT. PERFORMANCESTANDARDS(PARTC)TheProjectisrequiredtoadheretoLevel3FlowControlcriteria.TheLevel3performancecriteriarequiresthatthedevelopedcondition’sdurationsmustmatchthepredevelopeddurationsrangingfrom50%ofthetwo-yearpeakflowuptothefull50-yearpeakflowandalsomatchdevelopedpeakdischargeratestopredevelopedpeakdischargeratesforthe2-year,10-yearand100-yearreturnperiods(KCSWDM,Sec.I2).TheProjectwasevaluatedforonsiteinfiltrationanddispersionofroofdownspoutrunoff.ThelotshaveinsufficientspacetoallowforinfiltrationordispersionofroofrunoffandwillutilizethereducedimperviousfootprintBMPoption.TheBasicWaterQualityTreatmentgoalistoremove80%ofTSSforflowsorvolumesuptoandincludingtheWQdesignfloworvolume.ConveyancecriteriafortheProjectrequirethatallnewpipesbedesignedtoconveyandcontain(atminimum)the25-yearpeakflow.Theconveyancesystemwillconveythe100-yearpeakflowwithnoovertopping.FLOWCONTROLSYSTEM(PARTD)TheSitewillutilizeadetentionvaultmeetingtheLevel3FlowControlCriteria.TheKingCountyRunoffTimeSeries(KCRTS)softwarewasusedtosizethedetentionfacility.Thedetentionvaultdesigninformationisincludedinthissection.FLOWCONTROLBMPSELECTIONSubdivisionprojectsarerequiredtomitigateforimpervioussurfaceequaltoaminimumof10%ofeachlotareabyuseofFlowControlBestManagementPractices(BMP’s).ThereducedImperviousSurfaceCreditBMPasdescribedinAppendixC,SectionC.2.9oftheKCSWDMwillbeutilizedfortheProject.Themaximumimpervioussurfacecoverageallowedperzoningcodeforthetotallotarea75%.Theimpervioussurfacecreditisdefinedastheimperviousarearestrictedbelow4,000s.f.orthemaximumallowedbyzoningcode.Thetableonpage25ofthisreportreflectsthemaximumimperviousrestrictionandassociatedcreditforeachlot.VCwillutilizetherestrictedfootprintcredit,exclusively,whileVCllwillutilizerestrictedfootprintandfulldispersionintothetreeretentiontract.Arestrictedfootprintcovenantshallberecordedonthefaceofthefinalplatmap.ThissatisfiestheflowcontrolBMPrequirementsinSection1.2.3.3and5.2ofthe2009KCSWDM.©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage29TechnicalInformationReportcityofRenton FLOWCONTROLFACILITYDESIGNOUTPUTRetention/DetentionFacility©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage30CityofRentonTypeofFacility:DetentionVaultFacilityLength:82.0$ftFacilityWidth:$2.08ftFacilityArea:673$.sq.ftEffectiveStorageDepth:11.00ftStage0Elevation:357.50ftStorageVolume:74113.cc.ftRiserHead:11.00ftRiserDiameter:12.00inchesNumberoforifices:Orifice#123Height(ft)0.006.8010.003Diameter(in)1.042.0$1.97FullHeadDischarge(CFS)0.09$0.2400.105TopNotchWeir:NoneOutflowRatingCurve:NonePipeDiameter(in)6.04.0StageElevationStorageDischargePercolation(ft)(ft)(Cu.ft)(ac—ft)(cfs)(cfs)0.00357.500.0.0000.0000.000.01357.5167.0.0020.0030.000.02357.52135.0.0030.0040.000.03357.53202.0.0050.0050.000.04357.54270.0.0060.0060.000.05357.55337.0.0080.0070.000.07357.57472.0.0110.0080.000.08357.58539.0.0120.0080.000.09357.59606.0.0140.0090.000.30357.802021.0.0460.0160.000.52358.023504.0.0800.0210.000.73358.234918.0.1130.0250.000.95358.456401.0.1470.0290.001.17358.677883.0.1810.0320.001.38358.889298.0.2130.0350.001.60359.1010780.0.2470.0370.001.81359.3112195.0.2800.0400.002.03359.5313677.0.3140.0420.002.24359.7415092.0.3460.0440.002.46359.9616574.0.3800.0460.002.68360.1$18057.0.4150.0480.002.89360.3919471.0.4470.0500.003.11360.6120954.0.4810.0520.003.32360.8222369.0.5140.0540.003.54361.0423851.0.5480.0560.003.75361.2525266.0.5800.0570.00VuecrestEstates&VuecrestIIShortPlat 3.97361.4726748.0.6140.0590.004.19361.6928230.0.6480.0600.004.40361.9029645.0.6810.0620.004.62362.1231127.0.7150.0630.004.83362.3332542.0.7470.0650.005.05362.5534025.0.7810.0660.005.26362.7635439.0.8140.0680.005.48362.9836922.0.8480.0690.005.69363.1938337.0.8800.0710.005.91363.4139819.0.9140.0720.006.13363.6341301.0.9480.0730.006.34363.8442716.0.9810.0740.006.56364.0644198.1.0150.0760.006.77364.2745613.1.0470.0770.006.80364.3045815.1.0520.0770.006.82364.3245950.1.0550.0780.006.84364.3446085.1.0580.0820.006.86364.3646220.1.0610.0870.006.89364.3946422.1.0660.0950.006.91364.4146556.1.0690.1050.006.93364.4346691.1.0720.1160.006.95364.4546826.1.0750.1230.006.97364.4746961.1.0780.1270.006.99364.4947095.1.0810.1300.007.21364.7148578.1.1150.1540.007.43364.9350060.1.1490.1730.007.64365.1451475.1.1820.1890.007.86365.3652957.1.2160.2030.008.07365.5754372.1.2480.2160.008.29365.7955854.1.2820.2280.008.50366.0057269.1.3150.2390.008.72366.2258751.1.3490.2500.008.94366.4460234.1.3830.2590.009.15366.6561648.1.4150.2690.009.37366.2763131.1.4490.2780.009.58367.0864546.1.4820.2870.009.80367.3066028.1.5160.2950.0010.00367.5067375.1.5470.3030.0010.02367.5267510.1.5500.3040.0010.04367.5467645.1.5530.3080.0010.06367.5667780.1.5560.3120.0010.08367.5867914.1.5590.3190.0010.10367.6068049.1.5620.3260.0010.12367.6268184.1.5650.3360.0010.14367.6468319.1.5680.3450.0010.16367.6668453.1.5710.3520.0010.38367.8869936.1.6060.3820.0010.60368.1071418.1.6400.4050.0010.81368.3172833.1.6720.4260.0011.00362.5074113.1.7010.4430.0011.10368.6074787.1.7170.7590.0011.20368.7075460.1.7321.3300.0011.30368.8076134.1.7482.0700.0011.40368.9076808.1.7632.8700.00VuecrestEstates&VuecrestIIShortPlat©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage31CityofRenton HydR/DFacilityOutflow10.44230.300.2640.260.160.070.0780.06POCOutflowTargetCalc0.470.470.04***************0.330.05***************0.280.03***************0.04***************0.02***************0.02***************0.01***************RouteTimeSeriesthroughFacilityInflowTimeSeriesFile:rdin.tsfOutflowTimeSeriesFile:rdoutPOCTimeSeriesFile:dsoutInflow/OutflowAnalysisPeakInflowDischarge:PeakOutflowDischarge:PeakReservoirStage:PeakReservoirElev:PeakReservoirStorage:AddTimeSeries:bypass.tsfPeakSummedDischarge:9inYear89inYear80.471CFSat11:00onJan9inYear8VuecrestEstates&VuecrestIIShortPlat11.50369.0077482.1.7793.1600.0011.60369.1078155.1.7943.4200.0011.70369.2078829.1.8103.6600.0011.80369.3079503.1.8253.8900.0011.90369.4080177.1.8414.1000.0012.00369.5080850.1.8564.3000.0012.10369.6081524.1.8724.4900.0012.20369.7082198.1.8874.6700.0012.30369.8082872.1.9024.8500.0012.40369.9083545.1.9185.0200.0012.50370.0084219.1.9335.1800.0012.60370.1084893.1.9495.3400.0012.70370.2085567.1.9645.4900.0012.80370.3086240.1.98056400.0012.90370.4086914.1.9955.7900.00HydInflowOutflowPeakStorageStageElevfCu-Ft)(Ac-Ft)12.090.4411.00368.5074117.1.70121.030.3010.01367.5167445.1.54831.240.268.96366.4660374.1.38641.040.268.85366.3559600.1.36851.100.167.26364.7648907.1.12360.650.076.43363.9343318.0.99470.850.075.91363.4139826.0.91480.930.064.06361.5627321.0.627TributaryReservoirInflowInflow0.09********5670.280.180.090.080.062.09CFSat6:00onJan0.444CFSat11:00onJan11.00Ft368.50Ft74117.Cu—Ft1.701Ac—Ft©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage32CityofRenton PointofComplianceFile:dsout.tsfFlowfrequencyAnalysisTimeSeriesFile:rdout.tsfProjectLocation:Sea-Tac—-—AnnualFlowRate(CE’S)0.3820.0800.2810.0630.0860.1820.2790.47122/09/0171/06/0233/06/0388/26/0461/05/0551/19/06411/24/0611/09/0820:007:0022:006:0016:000:008:0011:00FlowDurationfromTimeSeriesFile:rdout.tsf---AnnualPeakFlowRates---FlowRateRankTimeofPeakFlowFrequencyAnalysis--Peaks--RankReturnProb(CE’S)(CE’S)(ft)Period0.35922/09/0120:000.44411.001100.000.07271/07/024:000.35910.21225.000.26033/06/0322:000.2608.97310.000.05988/26/047:000.2558.8545.000.07561/08/055:000.1597.2753.000.15951/19/060:000.0756.4362.000.255411/24/068:000.0726.0271.300.44411/09/0811:000.0594.0681.100.41610.7150.00ComputedPeaksFlowFrequencyAnalysisTimeSeriesFile:dsout.tsfProjectLocation:Sea-Tac0.9900.9600.9000.$000.6670.5000.2310.0910.980PeakFlowRates---RankTimeofPeakComputedPeaksFlowFrequencyAnalysis--Peaks—-RankReturnProb(CFS)Period0.4711100.000.9900.38$225.000.9600.281310.000.9000.27945.000.2000.18253.000.6670.08662.000.5000.08071.300.2310.06381.100.0910.44350.000.980CutoffCountFrequencyCDFExceedenceProbabilityCFS%0.0052945148.02848.02851.9720.520E+000.015807313.16561.19438.8060.38$E+000.025677311.04572.23927.7610.278E+000.03558299.50681.74518.2550.183E+000.04651228.35390.0989.9020.990E—010.05623333.80593.9026.0980.610E—010.06620083.27597.1772.8230.282E—010.07612822.09199.2680.7320.732E—020.08615$0.25899.5250.4750.475E—020.096230.03899.5630.4370.437E—020.10670.01199.5740.4260.426E—020.116110.01899.5920.4080.408E—020.126110.01899.6100.3900.390E—020.136260.04299.6530.3470.347E—020.146230.03899.6900.3100.310E—020.157300.04999.7390.2610.261E—020.167280.04699.7850.2150.215E—02VuecrestEstates&VuecrestIIShortPlat©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage33CityofRenton FlowDurationfromTimeSeriesFile:dsout.tsf0.177110.01899.8030.197O.197E—020.187120.02099.8220.178Ol78E—020.197100.01699.8390.161O.161E—020.20790.01599.8530.147O.147F—020.217130.02199.8740.126O.126E—020.22790.01599.8890.111O.111E—020.23790.01599.9040.096O.962E—030.247120.02099.9230.077O.766E—030.258160.02699.9490.051O.506E—030.268130.02199.9710.029O.294E—030.27820.00399.9740.026O.261E—030.28840.00799.9800.020O.196E—030.29$50.00899.9890.0110.114E—030.30$30.00599.9930.0070.652E—040.31$00.00099.9930.0070.652E—040.32$00.00099.9930.0070.652E—040.33$I0.00299.9950.0050.489E—040.34$00.00099.9950.0050.4$9E—040.35$20.00399.9980.0020.163E—04CDFExceedenceProbabilityCutoffCountFrequencyCFS%0.0062966$46.36248.38251.6180.516E+000.016860114.02662.40937.5910.376E+000.027682311.12773.53626.4640.265E+000.03$59379.68283.21816.7820.168E+000.04947097.67990.8979.1030.910E—010.06022033.59394.4905.5100.551E—010.07117362.83197.3212.6790.26$E—010.08211001.79499.1140.8860.$86E—020.0932350.38399.4980.5020.502E—020.104300.04999.5470.4530.453E—020.114160.02699.5730.4270.427E—020.125110.01899.5910.4090.409E—020.136150.02499.6150.3850.3$5E—020.147240.03999.6540.3460.346E—020.158220.03699.6900.3100.310E—020.169270.04499.7340.2660.266E—020.180240.03999.7730.2270.227E—020.1911$0.02999.8030.1970.197E—020.202130.02199.8240.1760.176E—020.21380.01399.8370.1630.163E—020.223100.01699.8530.1470.147E—020.234110.01899.8710.1290.129E—020.245110.01$99.8890.1110.111E—020.25680.01399.9020.0980.978E—030.267100.01699.9180.0820.815E—030.27$180.02999.9480.0520.522E—030.289130.02199.9690.0310.310E—030.30020.00399.9720.0280.277E—030.31140.00799.9790.0210.212E—030.32140.00799.9850.0150.147E—030.33230.00599.9900.0100.9785—04©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage34CityofRentonVuecrestEstates&VuecrestIIShortPlat 0.34320.0030.35400.0000.36510.0020.37600.0000.38720.003DurationComparisonAnaylsisBasefile:predev.tsfNewFile:dsout.tsfCutoffUnits:DischargeinCF’SEvaluatingFlowControlPerformance(KCSWDM3.3.2)I.Thepostdevelopmentflowdurationcurveliespredevelopmentcurveatthelowerlimitoftherangethe2-yearandthe2-year).Durationcomparisonanalysisshowsanegativepercentchangeupto0.192cfswhichisbeyondtherequired0.163cfslimit.2.Atanydurationwithintherangeofcontrol,thepostdevelopmentflowislessthanI.1timesthepredevelopmentflow.Atnodurationistheflowexceededbymorethan10%;themaximumpositiveexcursionis8.9%.3.Thetargetdurationcurvemaynotbeexceededalongmorethan50%oftherangeofcontrol.8outof15pointsshowanegativeexcursion.4.Thepeakflowattheupperendoftherangeofcontrol(reduced,25-year;historical,50year)maynotexceedpredevelopedlevelsbymorethan10%99.9930.0070.652E—0499.9930.0070.652E—0499.9950.0050.4$9E—0499.9950.0050.4$9E—0499.9980.0020.1635—04FractionofTimeCheckofToleranceCutoffBaseNew%ChangeProbabilityBaseNew%Change0.0810.95E—020.945—02—1.00.95E—020.0810.081—0.10.103I0.63E—020.45E—02—28.20.63E—020.1030.085—18.10.12610.50E—020.415—02—17.4I0.50E—020.1260.094—25.10.14810.37E—020.345—02—8.410.37E—020.1480.141—4.90.170I0.29E—020.265—02—8.60.29E—020.1700.165—2.70.192I0.22E—020.19E—02—12.5I0.225—020.1920.180—6.10.214I0.15E—020.16E—029.9‘0.15E—020.2140.2223.60.2370.1OE—020.125—0220.6I0.1OE—020.2370.2537.00.259I0.62E—030.955—0352.6I0.625—030.2590.2756.20.281I0.34E—030.39E—0314.3I0.345—030.2810.2851.50.3030.21E—030.245—0315.4I0.21E—030.3030.3143.40.326I0.16E—030.115—03—30.0I0.16E—030.3260.319—2.10.348I0.11E—030.65E—04—42.9I0.115—030.3480.327—6.00.370I0.165—040.49E—04200.00.165—040.3700.3874.7Maximumpositiveexcursion=0.022cfs(8.9%)occurringat0.241cfsontheBaseData:predev.tsfandat0.262cfsontheNewData:dsout.tsfMaximumnegativeexcursion=0.032cfs(-26.3%)occurringat0.122cfsontheBaseData:predev.tsfandat0.090cfsontheNewData:dsout.tsfstrictlyonorbelowtheofcontrol(between50%of©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage35CityofRentonVuecrestEstates&VuecrestIIShortPlat .Thepredev25-yearpeakis0.370cfs,thedsout25-yearpeakis0.388cfswhichequatestoa4.9%exceedanceandisthereforeacceptablebeinglessthantheallowable10%.—‘uI___ _ReturnPeriod5102050100L100tdoidpksmSooTa2edroutpusptedes.pus,R000__rr104OO.ip2,125102030708090959899©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReport405060CumulativeProbabilityPage36CityofRentonPEAKPLOT____5,C-)DURATIONANALYSISe-D5eMipeU,U-0rdoutdur0dsoutdur•target.Uur010ProbabilityExceedenceVuecrestEstates&VuecrestIIShortPlat WATERQUALITYTREATMENTSYSTEM(PARTE)TheProjectislocatedintheBasicWaterQualityTreatmentarea.Thetreatmentgoalis80%removaloftotalsuspendsolids(TSS)foratypicalrainfallyear,assumingtypicalpollutantconcentrationsinurbanrunoff.Thecombineddetention/waterqualityvaultwillaccommodatethisrequirement.Rainfall(R)ofthemeanannualstorm=0.47in.Areaofimpervioussurface(Ai)=155,933sf.Areaoftillsoilco’eredwithtillgrass(Atg)=81,783s.f.Areaoftillsoilco’redwithtillforest(Atf)=0s.f.Areaofoutwashsoilco’’eredwithgrassorforest(Ao)=0s.f.Volumefactor(f)=3N/ACalculationsUnitsVolumeofrunofffrommeanannualstorm(Vt)=6,297c.f.MinimumWetpoolvolumerequired(Vb)=18,892c.f.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage37TechnicalInformationReportCityofRenton FIGURE7DETENTION&WATERQUALITYFACILITYDETAILS©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage38TechnicalInformationReportCityofRenton FRNO7ES: SECTIONVCONVEYANCESYSTEMANALYSISANDDESIGNPerCR.#4oftheKCSWDM,theconveyancesystemmustbeanalyzedanddesignedforexistingtributaryanddevelopedonsiterunofffromtheproposedproject.Pipesystemsshallbedesignedtoconveythe100-yeardesignstorm.TheRationalMethodwillbeusedtocalculatetheQ-Ratioforeachpipenode.AconveyancesystemconsistingprimarilyofpipesandcatchbasinshasbeendesignedfortheProject.Onsiterunoffwillbecollectedbythemultiplecatchbasins.Pipesaretypicallytwelve-inchdiameterLOPEmaterial.Thepipeshaveaminimumslopeof0.50%.TheproposedconveyancesystemwillmeetalloftherequirementssetforthbytheManual.KCBWCalculationsareincludedinthisSection.Theupstreambypasspipes(P18,P19andP20)tobeinstalledwithinthefrontageimprovementsof102ndAveSE(MainAvenue5)aredesignedtoconveytheupstreamflowcurrentlydischarginginthatdirection.FieldreconnaissanceandCityGISindicatethatrunoffgeneratedislimitedtothewestsideofMainAve.S.(l02AveSE)fromjustsouthofSE188thStreettothesouthernboundaryoftheSite.Theareawestoftheroadwayslopestothewestandtheroadwayiscrownedsuchthattheeasternhalfdrainseast.Therefore,thetributaryareatothissystemtotals0.37acres(assumedtobe100%imperviousasaconservativemeasure).Utilizingtherationalmethod,itwasdeterminedthatthe100yearpeakflowis1.06cfs.Theproposed12-inchdiameter,ductileironpipewithaminimumslopeof0.50%iscapableofconveyingapproximately2.7cfs(SeeKCSWDMFigure4.2.1.F).Therefore,thesystemasdesignedisadequatetoconveytheupstreamrunoffasdepictedontheengineeringplans.©2016D.R.STRONGconsultingEngineersInc.TechnicalInformationReportSeeLevelTwoDownstreamAnalysisinAppendixAforanalysisofthevaultdischarge.Page39CityofRentonVuecrestEstates&vuecrestIIShortPlat BACKWATERANALYSISStormWaterRunoffVariables:A=TotalofSubasinandTributaryAreasc=RunoffCoefficient(theanticipatedproportionofrainfallvolumethatrunsoffthearea)see2009KCSWMTable32.1kCcCompositeRunoffCoefficientC=S(Cn*An)/ATvaT=TimeofConcentration,6.3minutesatupstreamendandincreasedby[(lengthofpipe)/6OV]foreachsubsequentreachR=designreturnfrequencyUnitpeakrainfallintensyfactorR(aXTC)’(-bR)aR,bR=coefficientsfrom‘98KCSWTVITable32.1BusedtoadjusttheequationforthedesignstormIsPeakrainfallintensityfactorforastormofreturnfrequencyRRPR*IRPR=totalprecipitation(inches)forthe24-hourstormeventforthegivenfrequency.SeeIssopluvialMapsin2OOKCSWK4Figures321A-Dpeakflow(cfs)forastormofreturnfrequencyR’QRCc*1R*ATheQ-Ratiodescribestheratioofthetnbutaryflowtothemainupstreamflow.R=j-yearstormaf=2.61bR=0.63RlinchesConveyanceSystemVariables:d=pipediametern=Manning’sNumber1=lengthofpipe)2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage40TechnicalInformationReportCityofRenton BASHPIPECBC8AlClA2D2AtCcTcPWOr(cfs)Q-ratioUMat’InISlopeFinEoutverfbw0FullVFutBendCBsfac.BusinTotalinft¾ftftftcfscfsdegreeaCB#8TOINLEI666526070.9290025289700.836.30823.190.180.180.0012LGFE0012300.5036625366.1369.252753.5002555425610.92850.25284600836.40.813.150.170.350.9712LtFE0.0121050.50366.10365.57369.222753.50101.52jn204-4204880.989710252945904Run4-3143060.9193702516243044—r--02545702107490173X1022521067218LCFE0012181L503607364i7371.278M5455104Run2034287160.9162700.254498613Ruin3-2129230.91420025143430241639091769002559329101760732t27354210118LCFE00121230503641363553748981045824jn102-24414091935025I6349C203TOC3203203203103155850.978980.25234830540686.30.823191031033131310.98372025215030490656.30.82319287160.91627002L44986t00.661*dB204TOC42041041559709842802524025055________-r-i-1120J4082aie1.17II374.45371377.4514.741876tI____—-.-6.968.69020.9o0.2510CBASNFEGBGBAlClA2c2AtCcTc0ROr(cfs)Q-ratioUMatCSfac.BasinTotaCkiCB#102TOC2182W2102!J5:o7oI63Io82l2.0.908.10.702720.006.240.0018LCFE0.0125.66.44362.86362.5376.2628.9516.388946T410410441615161164.5015115oiIo.e3.1914128740.910603234771.181.18108140.990171411413113121121111110110a137211109196310.616.40.81174630.9136303109312940.9744143825440.977781032210260.91141140990.607.00.760.0012LFEf0.012j27O31.5112Lc0170170001LOFE1.041.216.001LfDFELFE475680.95.49369.7136821372J19.071t59120.8214610.90.627.40.740.837.50.740.417.60.730.047.70.7252652842.030.6816216231.307260.060280.063.770.020.846.0OJO400.98406.850.848.70.700.284.415.62360.093.990.064.070.023.17400394.57405.986.898.7705.163393.09397.578.6071.2019.532039390.47396.096.938.8219.51.453389.86393.474.665.93204.3738383.02392.868,0910.3023.5Lcf:E10.0121536.1838379.74386.029.62376.75382.747.64122525.5©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportVuecrestEstates&VuecrestIIShortPlotPage41CityofRenton FIGURE8BACKWATERANALYSISMAP/PIPE-NODEDIAGRAM©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage42TechnicalInformationReportCityofRenton [:r VUECRESTESTATES a VUECRESTIISHORTPMT ti :•NODELINKDMGPAM - ;I CB6TOINLETI I =:-‘ / I NF;ThGRAPHICSCALE040801601INCH80FT.D£L /Z I eZ 90 ! ;;F VUECRESTESTATES VUECRESTIISHORTPLAT .NODE&LINKDMGPAM — :CBIO2TOcB2 j I i 1o 1m \ z -__ ,/N U .T VUECRESTESTATES VUECRESTIISHORTPLAT [[iDSJLLENGNEERS “NODE&L!NKDUGRAM CBX3TOcB3 Hi!LUC’)CikNDrn-i-i-GRAPHICSCALE04080160lB—iII BACKWATERANALYSISRESULTSPipedatafromfile:CB#6TOINLET1.bwpSurcharqeconditionatintermediatejunctionsTailwaterElevation:367.72feetDischargeRange:O.599to6.17StepofOverflowEievation:369.25feetWeir:NONEUpstreamVelocity:O.feet/sec0.599[cfs]362.86INLET:363.55INTYP:5DIA/WIDTH:4.0Q-RATIO:O15HWfFT)HWELEV.N-FACDCONTNDODEHWOHWI*********************************************************************4.19367.74*0.0120.290.204.874.874.194.190.374.20367.75*0.0120.410.284.874.874.194.200.554.24367.79*0.0120.510.344.894.894.214.240.694.29367.84*0.0120.590.404.914.914.244.290.824.36367.91*0.0120.660.444.944.944.284.360.944.44367.99*0.0120.730.494.984.984.334.441.054.54368.09*0.0120.790.535.025.024.384.541.164.65368.20*0.0120.850.575.085.084.454.651.284.78368.330.0120.900.605.135.134.524.781.394.93368.48*0.0120.950.645.205.204.604.931.505.08368.63*0.0121.000.675.275.274.695.081.62PIPENO.1:6LF—180986.44%OUTLET:362.50INLET:362.86INTYP:5JUNONO.1:OVERFLOW-EL:376.26BEND:89DEGDIA/WIDTH:4.0Q-RATIO:0.00Q(CFS)HW(FT)HWELEV.*N-FACDCUNTWDODEHWOHNI*******************************************************************************0.604.87367.73*0.0120.290.155.225.224.874.870.341.204.87367.73*0.0120.410.215.225.224.864.870.511.804.89367.75*0.0120.510.265.225.224.864.890.662.404.91367.77*0.0120.590.305.225.224.864.910.782.994.94367.800.0120.660.335.225.224.864.940.903.594.98367.84*0.0120.730.365.225.224.874.981.024.195.02367.88*0.0120.790.395.225.224.875.021.134.795.08367.94*0.0120.850.425.225.224.875.081.245.395.13367.99*0.0120.900.445.225.224.875.131.355.995.20368.06*0.0120.950.475.225.224.885.201.476.595.27368.13*0.0121.000.495.225.224.885.271.58Q255.33cfsQ1006.24cfsPIPENO.2:35LE-18”CP81.99%OUTLET:JUNONO.2:OVERFLOW-EL:377.29BEND:89DEGQ(CFS)0.601.201.802.402.993.594.194.795.395.996.59Q25.33cfsQ1006.24cfsPIPENO.3:123Lf—18’CP80.50%OUTLET:363.55INLET:364.17INTYP:5JUNONO.3:OVERFLOW-EL:374.89BEND:2DEGDIA/WIDTH:4.0Q-RATIO:1.01Q(CFS)HW(FT)HWELEV.*N-FACDCONTWDODEHWOHWI*******************************************************************************0.523.58367.75*0.0120.270.264.194.193.583.580.361.043.60367.77*0.0120.390.374.204.203.593.600.521.563.66367.83*0.0120.470.454.244.243.643.660.642.083.74367.91*0.0120.550.524.294.293.713.740.752.603.85368.02*0.0120.620.594.364.363.803.850.863.123.98368.150.0120.680.654.444.443.913.980.953.644.14368.310.0120.730.714.544.544.054.141.044.164.32368.49*0.0120.790.774.654.654.204.321.134.694.52368.69*0.0120.840.824.784.784.374.521.225.214.75368.92*0.0120.880.284.934.934.564.751.315.735.00369.17*0.0120.930.945.085.084.785.001.40Q254.63cfsQico5.42cfs©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage43CityofRentonVuecrestEstates&VuecrestIIShortPlat ©2016D.R.STRONGConsultingEngineersInc.Page44TechnicalInformationReportCityofRentonPIPENO.4:180Lf—18”CP@O.5OOUTLET:364.17INLET:365.07INTYP:5JUNCNO.4:OVERfLOW-EL:371.21BEND:10DEGDIA/WIDTH:4.0Q-RATIO:6.72Q(CFS)HW(FT)6WELEV.*NFACDCDNTWDODEHWOHWI*****************,**********************k*****************&****************0.262.69367.76*0.0120.190.193.583.582.692.690.250.522.70367.770.0120.270.263.603.602.702.700.360.782.77367.840.0120.330.323.663.662.772.770.441.042.87367.94*0.0120.380.373.743.742.862.670.511.292.99368.06*0.0120.430.413.853.852.972.990.581.553.13368.20*0.0120.470.453.983.983.123.130.641.813.31368.380.0120.510.494.144.143.283.310.702.073.51368.58*0.0120.550.524.324.323.483.510.752.333.74368.81*0.0120.580.564.524.523.703.740.812.594.00369.07*0.0120.610.594.754.753.954.000.862.854.28369.350.0120.650.625.005.004.224.280.91Q252:30cfsQioo2.70cfsPIPENO.5:105LE—12’1CP@0.50%OUTLET:365.57INLET:366.10INTYP:5JUNCNO.5:OVERFLOW-EL:369.22BEND:90Q(CFS)RW(FT)*******************0.031.670.071.670.101.740.131.840.171.960.202.110.232.290.272.490.302.720.332.98****************DIA/WIDTH:2.0Q-RATIO:0.97TWDODEHWOHWI********************************DEGHWELEV.N-FACDCON****************************367.77*0.0120.080.08367.77*0.0120.110.11367.84*0.0120.130.14367.94*0.0120.150.16368.06*0.0120.170.17368.21*0.0120.190.19368.39*0.0120.200.20368.59*0.0120.220.22368.82*0.0120.230.23369.08*0.0120.240.24OVERFLOWENCOUNTEREDAT0.372.192.191.671.670.102.202.201.671.670.142.272.271.741.740.172.372.371.841.840.202.492.491.961.960.222.632.632.112.110.252.812.812.282.290.273.013.012.492.490.293.243.242.722.720.313.503.502.972.980.32********OVERFLOWCONDITIONSCALCULATEDASSUMINGSURCHARGECONDITIONS*********0.373.26369.36*0.0120.260.253.783.783.263.260.34Q250.30cfsQioo0.35cfsCFSDISCHARGEPIPENO.6:29LF—12”CP@0.50%OUTLET:366.10INLET:366.25INTYP:5QfCFS)HW(FT)HWELEV.N-FACDCONTWDODEHWOHWI*******************************************************************************367.78367.77367.84367.94362.06368.21368.39368.59368.82369.020.021.530.031.520.051.590.071.690.091.810.101.960.122.140.142.340.152.570.172.830.193.12Q250.15cfsQ1000.18cfs*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.0120.060.080.100.110.120.140.150.160.170.171.671.671.741.841.962.112.292.492.722.980.060.080.100.110.130.140.150.160.170.170.190.181.671.671.741.841.962.112.292.492.722.981.531.521.591.691.811.962.142.342.572.831.531.521.591.691.811.962.142.342.572.83OVERfLOWENCOUNTEREDAT369.37*0.0120.180.070.100.120.140.160.170.190.200.210.23CF’SDISCHARGE3.263.263.113.120.24VuecrestEstates&VuecrestIIShortPlat Pipedatafromfile:CB#102TOCB12.bwpSurcharqeconditionatintermediatejunctionsTailwaterElevation:36$.53feetDischargeRange:O.03to0.33Stepof0.03[cfs]OverflowElevation:377.45feetWeir:NONEUpstreamVeiocity:O.feet/secPIPENO.1:23LF—12’CP@14.50%OUTLET:371.00INLET:374.45INTYP:5Q(CFS)HW(FT)NWELEV.*N-FACDCONTWDODERWOHWI*******************************************************************************0.030.08374.53*00120.080.040.000.040.080.040.060.10374.55*00120.100.050.000.050.100.060.090.13374.58*0.0120.130.060.000.060.13*****QQ90.120.15374.60*0.0120.150.070.000.070.150.120.150.16374.61*0.0120.160.080.000.080.160.140.180.18374.63*0.0120.180.080.000.080.180.160.210.19374.64*0.0120.190.090.000.090.190.180.240.21374.66*0.0120.210.090.000.090.21*****0.200.270.22374.67*0.0120.220.100.000.100.220.220.300.23374.68*0.0120.230.100.000.100.230.230.330.25374.70*0.0120.240.110.000.110.240.250.360.27374.72*0.0120.250.110.000.110.25*****0.27Q250.2$cfsQioo0.33cfsPipedatafromfile:CB#203TOCB#3.bwpSurchargeconditionatintermediatejunctionsTaliwaterElevation:369.feetDischargeRange:1.17to2.19Stepof0.102[cfs}OverflowElevation:376.2feetWeir:NONEUpstreamVelocity:0.feet/secPIPENO.1:23LF—12”CP80.51%OUTLET:368.14INLET:368.26INTYP:5JUNCNO.1:OVERFLOW-EL:374.89BEND:0DEGEllA/WIDTH:4.0Q-RATIO:0.87Q(CFS)HW(FT)HWELEV.*N-FACDCDNTWDODEHWOHWI*******************************************************************************1.170.83369.09*0.0120.460.460.860.860.760.830.651.270.85369.11*0.0120.480.480.860.860.760.850.681.370.86369.120.0120.500.500.860.860.760.860.711.480.88369.14*0.0120.520.530.860.860.760.880.741.580.90369.16*0.0120.540.550.860.860.770.900.781.680.92369.18*0.0120.560.570.860.860.770.920.811.780.94369.20*0.0120.570.590.860.860.780.940.841.880.96369.22*0.0120.590.610.860.860.780.960.871.990.98369.24*0.0120.610.630.860.860.790.980.902.091.00369.26*0.0120.620.660.260.860.791.000.932.191.03369.290.0120.64.0.680.860.860.801.030.962.291.06369.32*0.0120.650.700.860.860.811.060.99Q251.88cfsQioo2.19cfs©2016D.R.STRONGConsultingEngineersInc.Page45TechnicalInformationReportCityofRentonVuecrestEstates&VuecrestIIShortPlat Q(CFS)0.920.950.971.001.031.051.081.101.131.151.181.21Q251.01cfsQioo1.18cfsTWDO**********1.051.051.041.04LOS1.051.051.051.051.051.061.061.061.061.061.061.071.071.071.07L081.081.081.08DEHWOHWI********************0.41*****Q•540.41*****Q•550.42*****0.560.42*****Q•570.43*****0.580.44*****Q•590.44*****0.590.45*****0.600.45*****0.46*****0.620.46*****0.630.47*****0.64©2016D.R.STRONGConsulUngEngineersInc.TechnicalInformationReportVuecrestEstates&VuecrestIIShortPlatPIPENO.2:24LF—12”CP815.79%OUTLET:368.26INLET:372.20INTYP:5Q(CFS)RW(PT)RNELEV.N-FACDCDNTWDODEHWOHWI*********************************************************,**************-****0.630.38372.580.0120.330.140.830.830.330.6$0.40372.60*0.0120.350.150.850.850.350.400.740.42372.620.0120.360.150.860.860.360.420.790.44372.640.0120.380.160.880.880.3$0.440.840.46372.66*00120.390.160.900.900.390.460.900.48372.68*0.0120.400.170.920.920.400.480.950.50372.70*0.0120.410.170.940.940.410.501.010.52372.72*0.0120.430.180.960.960.43*****0.521.060.54372.74*0.0120.440.180.980.980.44Q541.120.56372.76*0.0120.450.191.001.000.45*****0.561.170.57372.77*0.0120.460.191.031.030.46*****0.571.230.59372.79*0.0120.470.201.061.060.47*****Q•59Q251.00cfsQ1001.17cfsPipedatafromfile:CB#204TOCB#4.bwpSurchargeconditionatintermediatejunctionsTailwaterElevation:369.19feetDischargeRange:1.1$to1.51Stepof0.033[cfs]OverflowElevation:372.71feetWeir:NONEUpstreamVelocity:0.feet/secPIPENO.1:23LF—12”CP811.21%OUTLET:365.57INLET:368.21INTYP:5JUNCNO.1:OVERFLOW-EL:371.21BEND:6DEGDIA/WIDTH:2.0Q-RATIO:0.28Q(CFS)RW(FT)HWELEV.*NFACDCONTWDOOPHWORET*******************************************************************************1.181.05369.26*0.0120.460.213.623.621.011.050.581.211.04369.25*0.0120.470.213.623.621.001.040.591.251.05369.26*0.0120.480.213.623.621.001.050.601.281.05369.260.0120.480.223.623.621.011.050.611.311.05369.26*0.0120.490.223.623.621.011.050.621.341.06369.27*0.0120.500.223.623.621.011.060.631.381.06369.27*0.0120.500.233.623.621.011.060.641.411.06369.27*0.0120.510.233.623.621.011.060.651.441.07369.28*0.0120.510.233.623.621.011.070.661.481.07369.28*0.0120.520.233.623.621.011.070.671.511.08369.29*0.0120.530.243.623.621.021.080.681.541.08369.29*0.0120.530.243.623.621.021.080.69Q251.30cfsQioo1.51cfsPIPENO.2:27LF-12”CP85.49%OUTLET:362.21INLET:369.71INTYP:5RW(FT)REELEV.*N-FACDCON*****************************************0.54370.25*0.0120.410.220.55370.26*0.0120.410.220.56370.270.0120.420.230.57370.28*0.0120.420.230.58370.29*0.0120.430.230.59370.30*0.0120.440.240.59370.30*0.0120.440.240.60370.31*0.0120.450.240.61370.32*0.0120.450.240.62370.33*0.0120.460.250.63370.34*0.0120.460.250.64370.35*0.0120.470.25Page46CityofRenton Pipedatafromfile:CB#17TOINLET2.bwpSurcharqeCOflditiQflatintermediatejunctionsTailwaterElevation:367.72feetDischargeRange:O.409to4.26Stepof0.409[cfs]OverflowElevation:4OS2feetWeir:NONEUpstreamVelocity:O.feet/sec9DEGDIA/WIDTH:2.0Q-RATIO:Q(CFS)HW(FT)HWELEV.N-EACDCDNTWDOIDEHWO***************************************************************************0.390.33380.07*0.0120.260.160.32O320.260.780.48380.220.0120.370.220.470.470.37*****1.170.60380.34*0.0120.460.270.590.590.461.560.71380.45*0.0120.540.310.700.700.54*****1.960.80380.54*00120.600.350.800.800.602.350.89380.63*0.0120.660.390.880.880.662740.97380.71*0.0120.710.420.970.970.713.131.05320.79*0.0120.760.451.071.070.76*****3.521.17380.91*0.0120.810.481.191.190.81*****3.911.29381.03*0.0120.840.511.321.320.84*****4.301.43381.17*0.0120.880.541.461.460.88Q253.48cfsQioo4.07cfsPIPENO.1:34LF—12’CP@20.62%OUTLET:367.00INLET:374.05INTYP:5JUNCNO.1:OVERFLOW-EL:379.05BEND:45DEGDIA/WIDTH:2.0Q-RATIO:0.01Q(CfS)HW(FT)NWELEV.*N-FACDCONTEDODEHWOEEl*******************************************************************************0.410.27374.32*0.0120.270.110.720.720.270.260.820.42374.47*0.0120.380.150.720.720.380.421.230.55374.60*0.0120.470.180.720.720.47*****Q551.640.66374.71*0.0120.550.210.720.720.550.662.050.77374.82*0.0120.620.240.720.720.620.772.450.87374.92*0.0120.680.260.720.720.68Q$72.860.98375.03*0.0120.730.280.720.720.73*****0.9$3.271.10375.15*0.0120.7$0.300.720.720.7$1.103.6$1.24375.29*0.0120.820.320.720.720.621.244.091.40375.45*0.0120.660.330.720.720.661.404.501.5$375.63*0.0120.690.350.720.720.691.5$Q253.64cfsQioo4.26cfsPIPENO.2:33LE-12”CP@7.97%OUTLET:374.05INLET:376.75INTYP:5JUNCNO.2:OVERFLOW-EL:379.75BEND:6DEGDIA/WIDTH:2.0Q-RATIO:0.03Q(CFS)HW(FT)HEELEV.N-FACDCDNTWDODEHWOHWI*******************************************************************************0.270.140.270.270.27*****0.320.3$0.190.420.420.3$0.470.470.230.550.550.470.590.540.270.660.660.54*****0.700.610.300.770.770.610.600.670.330.270.870.67*****0.730.350.980.980.730.970.770.381.101.100.771.070.820.401.241.240.821.190.860.431.401.400.861.320.890.451.581.580.891.46Q253.59cfsQioo4.20cfsPIPENO.3:76LE-12”CP63.90%OUTLET:376.75INLET:379.74INTYP:5JUNCNO.3:OVERFLOW-EL:382.74BEND:0.400.811.211.612.022.422.823.233.634.034.440.320.470.590.700.800.8$0.971.071.191.321.46377.07377.22377.34377.45377.55377.63377.72377.82377.94378.07378.21*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.0120.02EEl****0.330.480.600.710.800.890.971.051.171.291.43VuecrestEstates&VuecrestIIShortPlat©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage47CityofRenton Q253.17cfsQ1003.71cfsDEGQ(CFS)HW(FT)HWELEV.*N-FACDCDN***********************************************0.350.32390.79*0.0120.250.190.700.47390.94*0.0120.350.271.050.59391.06*0.0120.440.331.400.69391.16*0.0120.510.381.750.78391.25*0.0120.570.432.100.87391.34*0.0120.620.482.450.95391.42*0.0120.680.522.801.03391.50*0.0120.720.573.151.13391.60*0.0120.770.613.501.24391.71*0.0120.800.653.851.44391.91*0.0120.840.70Q253.12cfsQ1003.65cfs389.86INLET:390.47INTYP:5DIA/WIDTH:2.0Q-RATIO:0.08TWDODEHWOHWI********************************0.310.310.25*****0.320.460.460.35*****Q470.570.570.44*****Q590.670.670.51*****0.690.760.760.57*****0.780.850.850.620.870.930.930.68****0.951.001.000.72*****1.031.101.100.77*****1.131.211.210.881.201.241.321.321.141.441.36383.34383.49383.61383.72383.82383.91384.01384.10384.22384.36384.50*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.0120.260.370.460.530.600.650.710.760.800.840.870.140.200.240.2$0.310.340.370.390.420.440.470.330.4$0.600.710.800.890.971.051.17I.291.430.330.4$0.600.710.800.890.971.051.171.291.430.260.370.460.530.600.650.710.760.800.840.87*************************************0.320.470.590.700.800.890.991.081.201.341.48PIPENO.4:53LF—12’CP86.18%OUTLET:379.74INLET:383.02INTYP:5JUNC:NO.4:OVERFLOW—EL:386.02BEND:25DEGDIA/WIDTH:2.0Q—RATIO:0.0$Q(CFS)HWfFT)HWELEV.*N—FACDCDNTWDODEHWCHWI*******************************************************************************0.3$0.320.770.471.150.591.530.701.920.802.300.892.680.993.061.083.451.203.831.344.211.48Q253.41cfsQioo3.99cfsPIPENO.5:156LF—12”CP94.37%OUTLET:383.02INLET:389.86INTYP:5JUNCNO.5:OVERFLOW-EL:392.86BEND:23DEGDIA/WIDTH:2.0Q-RATIO:0.02Q(CFS)HW(FT)RWELEV.N-FACDCDNTWDODEHWOHWI*******************************************************************************0.360.31390.17*0.0120.250.150.320.320.25*****0.310.710.46390.320.0120.360.210.470.470.360.461.070.57390.43*0.0120.440.250.590.590.44*****Q571.420.67390.53*0.0120.510.290.700.700.51*****0.671.7$0.76390.62*0.0120.570.320.800.800.57*****0.762.140.85390.71*0.0120.630.360.890.890.630.852.490.93390.79*0.0120.680.390.990.990.680.932.851.00390.86*0.0120.730.421.081.080.73*****1.003.211.10390.96*0.0120.770.441.201.200.77*****3.561.21391.07*0.0120.810.471.341.340.811.213.921.32391.18*0.0120.850.501.481.480.85*****1.32PIPENO.6:42LF-12”CP81.45%OUTLET:JUNCNO.6:OVERFLOW-EL:393.47BEND:20VuecrestEstates&VuecrestIIShortPat©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage48CityofRenton 0.190.230.390.340.580.420.7$0.500.970.571.170.631.360.691.560.751.750.811.950.872.140.93Q251.73cfsQioo2.03cfsDIA/WIDTH:TWDO**********2.0Q—RATIO:0.6$DEHWOHWI********************0.19*****0.230.26*****0.340.32*****0.420.37*****0.500.42*****Q570.46*****0.630.50*****0.690.53*****0.750.57*****0.810.60*****0.870.63*****0.93©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportVuecrestEstates&VuecrestIIShortPlatPIPENO.7:81Lf—12”CP83.20%OUTLET:390.47INLET:393.09INTYP:5JUNCNO.7:OVERFLOW-EL:396.09BEND:19DEGDIA/WIDTH:2.0Q-RATIO:0.020(CFS)HW(FT)8WELEV.N-FACDCONTWDODEHWOHWI*******k**********************************************************************0.320.30393.39*0.0120.240.150.320.320.240.300.650.44393.53*0.0120.340.210.470.470.340.440.970.55393.640.0120.420.260.590.590.420.551.300.64393.73*0.0120.490.300.690.690.49*****0.641.620.73393.82*0.0120.550.330.780.780.55Q731.940.81393.90*0.0120.600.370.870.870.60*****0.812.270.88393.970.0120.650.400.950.950.65*****0.8$2.590.95394.04*0.0120.690.431.031.030.69*****Q952.921.02394.11*0.0120.740.461.131.130.741.023.241.11394.20*0.0120.780.491.241.240.78*****3.561.21394.30*0.0120.810.511.441.440.811.21Q252.88cfsQioo3.37cfsPIPENO.8:28LE—12”CP85.16%OUTLET:393.09INLET:394.57INTYP:5JUNCNO.8:OVERFLOW-EL:397.57BEND:19DEGDIA/WIDTH:2.0Q-RATIO:0.62Q(CFS)HN(FT)HWELEV.N-FACDCDNTWDODEHWOHWI*******************************************************************************Q252.81cfsQioo3.29cfsPIPENO.9:83.17%OUTLET:394.57INLET:400.98INTYP:5JUNCNO.9:OVERfLOW-EL:405.98BEND:0DEGQ(CFS)HW(FT)HWELEV.*N-FACDCON*************************************************0.320.630.951.271.5$1.902.212.532.853.163.480.290.430.550.650.750.$50.941.031.131.241.37394.$6395.00395.12395.22395.32395.42395.51395.60395.70395.81395.94*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.012*0.0120.240.340.410.4$0.540.590.640.690.730.770.800.130.190.230.260.290.320.350.370.400.420.440.300.440.550.640.730.810.880.951.021.111.210.300.440.550.640.730.810.8$0.951.021.111.210.240.340.410.4$0.540.590.640.690.730.770.80****************************************40.290.430.550.650.750.850.941.031.131.241.37202LF—12”CP401.21*0.0120.190.120.290.29401.32*0.0120.260.170.430.43401.40*0.0120.320.200.550.55401.48*0.0120.370.230.650.65401.55*0.0120.420.260.750.75401.61*0.0120.460.280.850.85401.67*0.0120.500.310.940.94401.73*0.0120.530.331.031.03401.79*0.0120.570.351.131.13401.85*0.0120.600.371.241.24401.91*0.0120.630.391.371.37Page49CityofRenton PIPENo.10:220LF—12”CP@1.30%OUTLET:400.9$INLET:403.85INTYP:5JUNCNo.10:CVERFLQWEL:406.85BEND:36DEGDIA/WIDTH:4.0Q-RATIO:6.00Q(CfS)HW(FT)HWELEV.*N-FACDCDNTWDODEHWOHWI0.120.18404.03*0.0120.140.120.230.230.140.180.230.26404.11*0.0120.200.160.340.340.200.260.350.33404.18*0.0120.250.200.420.420.250.330.460.38404.23*0.0120.290.220.500.500.29Q3$0.580.43404.280.0120.320.250.570.570.320.430.700.48404.33*0.0120.350.270.630.630.35*****0.480.810.52404.37*0.0120.380.300.690.690.380.520.930.56404.410.0120.410.320.750.750.41*****0.561.040.60404.45*0.0120.430.340.810.810.43*****0.601.160.64404.490.0120.460.360.870.870.46*****0.641.280.68404.53*0.0120.480.370.930.930.48*****0.68Q251.03cfsQico1.21cfsPIPENO.11:41LE—12”CP83.25%OUTLET:403.85INLET:405.20INTYP:5QfCFS)RW(FT)HWELEV.N-FACDCDNTWDODEHWOHWI*******************************************************************************0.020.06405.26*0.0120.060.040.180.180.060.060.030.08405.28*0.0120.080.050.260.260.080.0$0.050.11405.31*00120.100.070.330.330.10*****0.070.12405.32*0.0120.110.070.3$0.3$0.11*****0.120.080.14405.340.0120.120.080.430.430.12*****0.140.100.16405.360.0120.130.090.4$0.4$0.130.160.120.17405.37*0.0120.140.090.520.520.14*****0.170.130.1$405.38*0.0120.150.100.560.560.15*****0.1$0.150.20405.40*0.0120.160.110.600.600.160.200.170.21405.41*0.0120.170.110.640.640.17*****0.210.1$0.22405.42*0.0120.1$0.120.680.6$0.1$0.22Q250.15cfsQ1000.17cfsVuecrestEstates&VuecrestIIShortPlat©2016D.R.STRONGConsultingEngineersInc.TechnicalInformationReportPage50CityofRenton SECTIONVISPECIALREPORTSANDSTUDIESSeeTIRVolumeiiforthefollowingreportsandstudies.VuecrestEstatesI.TrafficImpactAnalysis—TraffEx,Inc.April23,20132.CriticalAreaStudy—WetlandResources,Inc.April8,20133.SupplementalStreamStudy—WetlandResources,Inc.MayI0,20134.GeotechnicalEngineeringStudy—EarthSolutionsNWLLC,February25,20135.GeotchnicalReview—AssociatedEarthSciences,Inc.,October31,20136.ResponsetoGeotechnicalReview—EarthSolutionsNWLLC,December2,20137.GeotechnicalReviewofPermitDocuments—HartCrowser,February24,20148.SlopeStabilityAnalysis—EarthSolutionsNWLLC,April10,20139.ProposedStormwaterVault—EarthSolutionsNWLLC,June24,201410.VuecrestArboristReport—GreenforestIncorporated,September8,201511.VuecrestEstatesHydrologyStudy—EdMcCarthy,P.E.,P.S.,January26,201612.GeotechnicalAddendum,VuecrestEstates(ScourAnalysis)—EarthSolutionsNWLLC,RevisedApril7,201613.GeotechnicalAddendum,VuecrestEstates(CulvertFootingBearingCapacity)—EarthSolutionsNWLLC,RevisedJune6,201614.PermanentSlopeAdjacenttoCulvert,VuecrestEstates—EarthSolutionsNW,LLC,August15,2016VuecrestIIShortPlat1.FinalTreeProtectionPlan—WashingtonForestryConsultants,Inc.,Dec19,20142.GeotechnicalEngineeringStudy—EarthSolutionsNWLLC,December15,20143.CriticalAreasStudy—WetlandResources,Inc.January5,2015©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage51TechnicalInformationReportCityofRenton SECTIONVIIOTHERPERMITS,VARIANCESANDADJUSTMENTS.ApprovedStreetModification—VuecrestIIShortPlat,April24,2015.CriticalAreaExemption—VuecrestEstatesIVuecrestIIShortPlat,pending.HydraulicProjectApproval(HPA)—VuecrestEstates,pending.DOEConstructionStormwaterGeneralPermit—March31,2016,WAR303895©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage52TechnicalInformationReportcityofRenton SECTIONVIIIESCPLANANALYSISANDDESIGN(PARTA)TheErosionandSedimentationControlDesignmeetsthenineminimumrequirements:1.ClearingLimits—Areastoremainundisturbedshallbedelineatedwithahigh-visibilityplasticfencepriortoanysiteclearingorgrading.2.CoverMeasures—DisturbedSiteareasshallbecoveredwithmulchandseeded,asappropriate,fortemporaryorpermanentmeasures.3.Perimeterprotection—Perimeterprotectionshallconsistofasiltfencedownslopeofanydisturbedareasorstockpiles.4.TrafficAreaStabilization—Astabilizedconstructionentrancewillbelocatedatthepointofingress/egress.5.SedimentRetention—SurfacewatercollectedfromdisturbedareasoftheSiteshallberoutedthroughasedimentvaultorsedimenttrapspriortoreleasefromtheSite.Thesedimentvaultortrapswillbeinstalledpriortogradingofanycontributingarea.6.SurfaceWaterControl—Interceptorbermsorswalesshallbeinstalledtocontrolandinterceptallsurfacewaterfromdisturbedareas.Surfacewatercontrolsshallbeinstalledconcurrentlywithand/orimmediatelyfollowingroughgtading.7.DewateringControl—Willbeprovidedasneeded.8.DustControl—Dustcontrolshallbeprovidedbysprayingexposedsoilswithwateruntilwet.Thisisrequiredwhenexposedsoilsaredrytothepointthatwindtransportispossiblewhichwouldimpactroadways,drainageways,surfacewaters,orneighboringresidences.9.FlowControl—Runoffcollectedinthesedimentvaultwilldischargetothepermanentdetentionvaultoutfallsystem.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIlShortPlatPage53TechnicalInformationReportCityofRenton swppsPLANDESIGN(PARTB)Constructionactivitiesthatcouldcontributepollutantstosurfaceandstormwaterincludethefollowing,withapplicableBMP’slistedforeachitem:1.Storageanduseofchemicals:Utilizesourcecontrol,andsoilerosionandsedimentationcontrolpractices,suchasusingonlyrecommendedamountsofchemicalmaterialsappliedinthepropermanner;neutralizingconcretewashwater,anddisposingofexcessconcretematerialonlyinareaspreparedforconcreteplacement,orreturntobatchplant;disposingofwash-upwatersfromwater-basedpaintsinsanitarysewer;disposingofwastesfromoil-basedpaints,solvents,thinners,andmineralspiritsonlythroughalicensedwastemanagementfirm,ortreatment,storage,anddisposal(TSD)facility.2.Materialdeliveryandstorage:Locatetemporarystorageareasawayfromvehiculartraffic,neartheconstructionentrance,andawayfromstormdrains.MaterialSafetyDataSheets(MSDS)shouldbesuppliedforallmaterialsstored,andchemicalskeptintheiroriginallabeledcontainers.Maintenance,fueling,andrepairofheavyequipmentandvehiclesshallbeconductedusingspillpreventionandcontrolmeasures.Contaminatedsurfacesshallbecleanedimmediatelyfollowinganyspillincident.Providecover,containment,andprotectionfromvandalismforallchemicals,liquidproducts,petroleumproducts,andotherpotentiallyhazardousmaterials.3.Buildingdemolition:Protectstormwaterdrainagesystemfromsediment-ladenrunoffandlooseparticles.Totheextentpossible,usedikes,berms,orothermethodstoprotectoverlanddischargepathsfromrunoff.Streetgutter,sidewalks,driveways,andotherpavedsurfacesintheimmediateareaofdemolitionmustbesweptdailytocollectandproperlydisposeofloosedebrisandgarbage.Spraytheminimumamountofwatertohelpcontrolwindblownfineparticlessuchasconcrete,dust,andpaintchips.Avoidexcessivesprayingsothatrunofffromthesitedoesnotoccur,yetdustcontrolisachieved.Oilsmustneverbeusedfordustcontrol.4.Sawcutting:Slurryandcuttingsshallbevacuumedduringtheactivitytopreventmigrationoffsiteandmustnotremainonpermanentconcreteorasphaltpavingovernight.Collectedslurryandcuttingsshallbedisposedofinamannerthatdoesnotviolategroundwaterorsurfacewaterqualitystandards.ThecompleteCSWPPPcanbefoundinAppendixB.©2016D.R.STRONGconsultingEngineersInc.VuecrestEstates&Vuecrest1ShortPlatPage54TechnicalInformationReportcityofRenton SECTIONIXBONDQUANTITIES,FACILITYSUMMARIES,ANDDECLARATIONOFCOVENANT1BondQuantityWorksheet—AppendixC•‘2.TheStormwaterFacilitySummarySheetisincludedinthissection3.DeclarationofCovenantforPrivatelyMaintainedFlowControlandWaterQualityFacilities—Notapplicable.4.DeclarationofCovenantforPrivatelyMaintainedFlowControlBMPs—adraftisprovidedwiththissubmittal.©2016D.R.STRONGConsulUngEngineersInc.VuecrestEstates&Vuecrest1ShortPlatPage55TechnicalInformationReportCityofRenton STORMWATERFACILITYSUMMARYSHEETDevelopmentVuecrestEstates&VuecrestIIShortPlatDateSeptember17,2015Location4800BlockofSmithersAvenueS,Renton,WAENGINEERDEVELOPERNameMaherA.Joudi,P.E.NameFirm0.R.STRONGConsultingFirmHarbourHomes,LLCEngineers,Inc..Address10604NE38thPlace,#232Address1441North34thStreet,Suite200Kirkland,WA98033Seattle,WA98103Phone(425)827-3063Phone(206)315-8130DevelopedSite:5.87acresNumberoflots28Numberofdetentionfacilitiesonsite:Numberofinfiltrationfacilitiesonsite:__jvault_ ______vaults—pond_ _____vaults_____tankstanksFlowcontrolprovidedinregionalfacility(givelocation)___________________________________Noflowcontrolrequired_____ExemptionnumberDownstreamDrainageBasinsImmediateMajorBasinBasinBlackRiverDuwamish—GreenRiverNumber&typeofwaterqualityfacilitiesonsite:_____ __biofiltrationswale(regular/wet!orcontinuousinflow?)_ ______sandfilter(basicorlarge?)_______sandfilter,linear(basicorlarge?)______CONTECHStormfilterIcombineddetentionlWQvault_____sandfiltervault(basicorlarge?)_____ _combineddetention/wetpond____ ___stormwaterwetland_______compostfilter___ ____wetvault(basicorlarge?)____ ___filterstrip____ ___Wetvault____ ___flowdispersion_______pre-settlingpond_____ _farmmanagementplan_ _____flow-splittercatchbasin______landscapemanagementplan______ _oil/waterseparator(baffleorcoalescingplate?)©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage56TechnicalInformationReportCityofRenton ______catchbasininserts:Manufacturer______________________pre-settlingstructure:ManufacturerDESIGNINFORMATIONINDIVIDUAL_BASINWaterQualitydesignflowWaterQualitytreatedvolumeDrainagebasin(s)Onsitearea(includesfrontage)5.87Offsite_areaTypeofStorageFacilityVaultLiveStorageVolume(reauired)74,113PredevRunoffRate2-year0.16310-year0.284I00-year0.474DevelopedRunoffRate2-year0.086(Usout.tsf)10-year0.281I00-year0.471TypeofRestrictorFrop-TeeSizeoforifice/restrictionNo.II.04No.22.08No.31.97©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortFlatPage57TechnicalInformationReportcityofRenton SECTIONXOPERATIONSANDMAiNTENANCEMANUALTheHomeOwnersAssociationwillberesponsibleformaintenanceofthe50-footdispersaltrench,locatedinTractC,towhichLot8ofVCI1drains.TheAssociationwillalsoberesponsibleformaintenanceofseveralprivatecatchbasinsonvariouslotsasdepictedontheplans.Maintenanceguidelinessetforthinthe2009KCSDWDMareincludedinthissection.Allotherdrainageelementsaretobepubliclymaintained.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage58TechnicalInformationReportcityofRenton NO.5—CATCHBASINSANDMANHOLESMyeiidencceconan*ansorpIutorisuchasoilgaso4ine.ncretesIurieorpaint.Sumofcacbasc-.i;.rMaterialsremosdanddisposedcLraccrdH9toapp1)caberegu1aicnsSourceconrcBMPsimplementedifappropiaeNoccntaninanlspresentcitherthanasurfaitim.©2016D.R.STRONGConsultingEngineersInc.TechnicallnformationReportPage59CityofRenton&int€i3nceDefectorProblemConditionVVenMaintenanceisNdedResultsExpectedWhenConiponentMaintenanceisPer1omed3elinie-texeis)%oftiefromtb:i:ct-e:;i&basnto:hewerftheIc:we:iet:rC.i:bas9rISWt9TI”:resofteis’-tct9elcwes:iiçeir:ccoitoftiecat::’,DaSIrTrasranddebrisTrashordebrsnrethicubccctwflicliNrasnordebnsbIOciTIorISCeCITThI3&yflfrCtCtreDa12bas,nocer1atlyIodcinçenta*C+efliTrIsblc:kinçc..spa&yoftiecatchtasInt&bsnbmorethan%.:lI-ashordebrisintheca:chasrma:eeedsNotS9ordebrisntecat±ssn:medeptnfromthebottomofbasintorrvrtthelowiss:pipeintooroutcthessirDeadarr..sovege.aicrthatudgeneraeNoder:asorcwor5thatudcauseccrrpwtsordangerousprese9twr.hncatchb.ssin.gasesmetnarte.DeFoStsofgathageexedng1cubicfootnNonthiionpresentwiizwouldIumeatiractorsupporthebreedi.ofInsectsorroceritsDz(r..SetoframeCornercfraneextendSmoreth9¾nchrastFrameiseenwithcurbanWtopslabcurbfaceintothesteetfpp1icae).Topslabhasholeslargerthan2squareinchesorTopslabisfreeoholesandcracks.cracksviderthan¼inch.Frarrrts4tbngflushcrtopab.Le.,Frameissrbngushontopslab.sep%3raior:cifmorethan¾inchofthefranefrrmtnetopslab.CracksnwallsorCracksw4derthantinchandIgerthan3feet.Catchbasinissealedandbottomanyeidenceofsoilparticlesenteringcstchstructurallysound.baslnthroughcracks,ormaintenancepersonjudgesthatcatchbaslnisunsound.Cracksw%derthan4inchandlcethanfootNccracksmorethaninchwideatathejotcanylnletfoletpipeorwryedence1hejtrItO1nIetOUfletpipecfsoilparticlesenteringcatchbasinthrouhcracks.SettlernenJCatchbasinhassetiednxethan1inchorhasBasinreplacedorrepredtodesignrrsaiignrrntrotatedirorethan2chesout&alignmentstsndards.DamagedpipejointsCracksw4derthan½-inchatthejointoftheNccracksmorethan3%-inchwdeatinietoutletpipesoranyeidenceofstenteringthejntofinletiouffetpipes.thecatchbaslnathejntotheinlet1ouetpes.ontarrinantsandpoutioninletOuUetPipeSedirrntSedirrertfilling2D%ormorecPthepipe.ln1etoutletpipesdearofsedimentaocumulationTrashanddebrisTrashanddebrisaocumulatedininlet1outletNofrasliordebrisinpipes.pipesfindudesoatablesandnon-oatsblesDxr3gedCracksw5derthan½-inchatthejdntoftheNccracksmorethanY.-nchwideatinlehoutietpipesoranyetidenoeofsoilentehngIhejntoftheinletoutletpipe.3thejointsoftheinlesouIepipes.VuecrestEstates&VuecrestIIShortPlat NO5—CATCHBASINSANDMANHOLESMaiflten3nceDefectorProblemConditionWbenMaintenanceisNeddResultsExpectUWhenConiponent_____________________________________MaintenanceisPertcrrneUMet:‘r:eJfeçatpeitrç:tt-m..rd.E:-iecengrneetce:C—t:-Easrst!9dis.TrEddeDr.Trashiie:isttisIc>rnret92D%3iereeofrh.iie:is.C’.ratCsuace.fctnc:ebgu:iesfocsca:aeorGiternssorbrokenmem:es;cf:heça:eGratesinpeancr-eetesrAnyopenstructurerequiresurgenttndds.rnantenarceManhoieCoerUdCaernonpeCcr1idismissinorontypabaJiyinpaceD’er1icptectscoentoAnyopenstructurerequiresurgentStrUtJre.rnanteranceockgme:hnismMe&a9ismnnotheopeecbyonetechiismopew:hpce:co1c4WCT.gmatenaee-sowippetcIs.ttt.scarteea:ea.Se-Ickco.er:1icoes‘ac:wo&Ccweridizfjft:oC-emai..te-eperorcannoreneCoer1idcabereneIanerrcve:er’hafterapp’,n;Bbsofretatedbyoneanenanper5oDispersionTrenchDispersiondevicesmustbeinspectedannuallyandaftermajorstormeventstoidentifyandrepairanyphysicaldefects.Whennativesoilisexposedorerosionchannelsarepresent,thesourcesoftheerosionorconcentratedflowneedtobeidentifiedandmitigated.Barespotsshouldbere-vegetatedwithnativevegetation.Concentratedflowcanbemitigatedbylevelingtheedgeoftheperviousareaand/orregardingorreplenishingtherockinthedispersiondevice,suchasinrockpadsandgravel-filledtrenches.©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage60TechnicalInformationReportCityofRenton APPENDICES©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage61TechnicalInformationReportCityofRenton APPENDIX“A”OFFSITEANALYSIS’©2016D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage62TechnicalInformationReportCityofRenton 3MLEVELIOFF-SITEDRAINAGEANALYSISTaskISTUDYAREADEFINITIONANDMAPSTheVuecrestIIprojectisaproposedshortplat,consistingof8lots.Thesiteislocatedonthewestsideof102ndAveSE,nearthe102ndAveSE&SE186thStreetintersection,inaportionofSection32,Township23North,Range05East,W.M.,intheCityofRenton.Theprojectsiteis2.45acresinsize(or106,680squarefeet).Thepropertyconsistsofonetaxparcel(TaxLotNo.3223059097)andthereisonesingle-familyhomelocatedonsite(eastsideofproperty)aswellasseveralassociatedoutbuildings,utilities,andprivategravelaccessdrive.Amajorityofthepropertyisaforestedarea(coveredwithmixeddeciduous/coniferoustrees;pleasereferencetheTreeProtectionPlanpreparedbyWashingtonForestryConsultants,Inc.)andasmallwetlandlocatedinthenorthwestcorneroftheproperty(CategoryIIWetland;pleasereferencetheCriticalAreaStudypreparedbyWetlandResources,Inc.).Thesitegenerallyslopesfromtheeasttowest(approximately35feetinelevationchange),withaslopeaveragingfrom1%to2%.However,inasmallareainthenorthwestcornerofthesite(neartheon-sitewetland),thetopographyincreasesbetween30%and35%.Pertheprojectsurveyor,therearenoslopesonsitethatexceed40%(asdefinedinRMC4-11-190,Slope,ProtectedandSlopeSensitive).Allsignificanttreesonthesitehavebeensurveyed(6-inchdiameteratbreastheight[DBH]orgreater)andareshownandidentifiedontheTreeRetentionPlanpreparedbyBarghausenConsultingEngineers,Inc.TheunderstorycoverismixedwithSalmonberry,VineMaple,WesternHazelnut,Swordfern,Salal,Oregongrape,PacificBlackberry,andportionsofthepropertyhaveornamentallandscapingandgrassareas(aroundandneartheexistingresidence).Theon-sitesoilsconsistofapproximately4to18inchesoftopsoiloverlyingnativesoilsconsistingprimarilyofmediumdensetodensesiltysandandsandysiltglacialtilldepositswhichareoneofthemorecommonsoiltypesinandaroundtheCityofRenton.PleaseseetheGeotechnicalReportpreparedbyEarthSolutionsNWdatedDecember15,2014.Asdiscussedearlier,asmallwetlandislocatedinthenorthwestcornerofthepropertyandisclassifiedasaClassIIWetlandrequiringa50-footbuffer.Theproposedprojectisutilizingbufferaveragingtoallowfortheconstructionandfutureextensionoftheon-sitepublicroadway(proposedRoadA).PleasereferencetheCriticalAreaStudypreparedbyWetlandResources,Inc.datedDecemberJanuary5,2015.Accesstothesiteisfrom102ndAvenueS.E.(residentialaccessstreet).Apublicroadwillbeconstructedtoprovideaccesstothe8lots,andwillbeextendedasfarnorthaspossiblesothattheneighboringpropertytobedevelopedbyHarbourHomes(VuecrestEstates;CityFileNo.LUAI3-000642)canextendtheroadwayforsecondaryaccess.Theprojectsiteissurroundedbyexistingsingle-familysubdivisionswithsimilardensities;however,alongthesouthpropertylinetherearelargersingle-familylots(duetotopography)thatrangefromIto2acresinsize.Asdesigned,thereareapproximately690linealfeetofproposedon-sitepublicright-of-way(halfstreet),whichwillhave32to39.5feetofpublicright-of-waywith20to26feetofpaving,curb,gutter,planter(8feetwideinportions),andsidewalk(5feetwide).Theprojectdevelopmentwillutilizeandextendexistingpublicutilitiesthroughtheprojectsite(waterandsewerprovidedbySoosCreekWaterandSewerDistrict)alongwithstormdrainageanddryutilities(power,telephone,naturalgas,andcable)servingalllots.SewerwillbeextendedfromthePlatofVuecrestEstates(CityFileNo.LUAI3-000642)tothewestpropertylineoftheVuecrestIIShortPlat.PleasereferencetheConceptualUtilityPlanpreparedbyBarghausenConsultingEngineers,Inc.formoredetailedinformation.17254.OO1-TIR.doc Inordertoconstructtheprojectasgenerallydepictedonthepreliminarygradingplan,approximately105acreswillbecleared.Approximately7,600cubicyardsofstructuralsoilwillbecutforgradingtheroadsandlots.Amajorityofthiscutmaterialwillbeusedonsitetoconstructtheprojecttothefinaldesigngrades.Anyexcessstructuralmaterialwillbeexportedfromthesiteduringconstructionalongwithanyexcesstopsoil.Thesefiguresareapproximateandwillbedeterminedatfinalengineeringdesign.StormwaterrunofffromtheVuecrestIIprojectwillbeconveyedoffsitetothedrainagefacilityforVuecrestEstates,whichwillbesizedtoincludethefuturedevelopedsiteareafromtheVuecrest11project.Theoff-sitedrainagefacilitywillberequiredtoprovideBasicWaterQualityTreatmentandLevel3FlowControlforthedevelopedareasfromthisproject,followingthe2009KingCountySurfaceWaterDesignManual(KCSWDM).TheprojectislocatedinaConservationFlowControlarea(Level2FlowControl);however,asnotedintheTIRpreparedbyDRStrongConsultingEngineers,Inc.fortheVuecrestEstatesproject,duetoaconnectionthroughthedownstreamsystemtheprojectwilladheretoLevel3FlowControlrequirements.ATechnicalInformationReport(TIR)hasbeenpreparedbyDRStrongConsultingEngineers,Inc.fortheVuecrestEstatesproject,datedJuly15,2014,whichwillbeupdatedduringfinalengineeringdesigntoincludedevelopedareasfromtheVuecrestIIproject.ALevelTwoDownstreamAnalysiswasalsopreparedbyDRStrongConsultingEngineers,Inc.fortheVuecrestEstatesproject,datedJuly15,2014,whichwillalsobeupdatedduringfinalengineeringdesigntoincludetheVuecrestIIproject.I7254.OO1-TIR.doc TASK2RESOURCEREVIEWAdoptedBasinPlans:Noneavailableatthistime.FinalizedDrainageStudies:Thisisnotapplicable.BasinReconnaissanceSummaryReport:ThesiteislocatedwithintheBlackRiverBasin,includedinReconnaissanceReportNo.14,preparedJune1987,includedinSection6.0ofthisreport.CriticalDrainageAreaMaps:AccordingtotheWaterQualityApplicationsMapinthe2009KingCountySurfaceWaterDesignManual(KCSWDM),BasicWaterQualityTreatmentisrequired.AccordingtotheFlowControlApplicationsMap(alsointheKCSWDM),ConservationFlowControlisrequired;however,asnotedintheTIRpreparedbyDRStrongConsultingEngineers,Inc.fortheVuecrestEstatesproject,duetoaconnectionthroughthedownstreamsystemtheprojectwilladheretoLevel3FlowControlrequirements.FloodplainandFloodwayFEMAMaps:PleaseseetheattachedFEMAMap(Section1.0)utilizedforthisanalysis.AsindicatedonthemapthesiteislocatedinZoneXandisoutsideofthe500-yearfloodplain.OtherOff-SiteAnalysisReports:ALevelTwoDownstreamAnalysiswasalsopreparedbyDRStrongConsultingEngineers,Inc.fortheVuecrestEstatesproject,datedJuly15,2014,whichwillalsobeupdatedduringfinalengineeringdesigntoincludetheVuecrestIIproject.SensitiveAreasFolios:BasedonareviewoftheKingCountySensitiveAreasMapFolios,thesitedoesnotcontainanyOn-SiteWetlands,ErosionSensitiveAreas,orLandSlideAreas.However,throughfieldsurveyandanalysisithasbeendeterminedthatthereisawetlandon-site.AsmallwetlandislocatedinthenorthwestcornerofthepropertyandisclassifiedasaClassIIWetlandrequiringa50-footbuffer.Theproposedprojectisutilizingbufferaveragingtoallowfortheconstructionandfutureextensionoftheon-sitepublicroadway(proposedRoadA).PleasereferencetheCriticalAreaStudypreparedbyWetlandResources,Inc.datedDecemberJanuary5,2015.RoadDrainageProblems:Thisisnotapplicable.UnitedStatesDepartmentofAgricultureKingCountySoilsSurvey:BasedontheSoilsMap(seeFigure3—SoilsMapSection1.0)forthisarea,themajorityofthesiteislocatedinthesoilsconfigurationknownasAlderwoodgravellysandyloam.Theon-sitesoilsconsistofapproximately4to18inchesoftopsoiloverlyingnativesoilsconsistingprimarilyofmediumdensetodensesiltysandandsandysiltglacialtilldepositswhichareoneofthemorecommonsoiltypesinandaroundtheCityofRenton.PleaseseetheGeotechnicalReportpreparedbyEarthSolutionsNWdatedDecember15,2014.WetlandInventoryMap:AsmallwetlandislocatedinthenorthwestcornerofthepropertyandisclassifiedasaClassIIWetlandrequiringa50-footbuffer.Theproposedprojectisutilizingbufferaveragingtoallowfortheconstructionandfutureextensionoftheon-sitepublicroadway(proposedRoadA).PleasereferencetheCriticalAreaStudypreparedbyWetlandResources,Inc.datedDecemberJanuary5,2015.MigratingRiverStudies:Thisisnotapplicable.CityofRentonAquiferProtectionZones:PertheCityofRenton’sGISMaptheprojectsiteisnotlocatedwithinanAquiferProtectionZone.17254.001-TIRdoc TASK3FIELDINSPECTIONThefieldreconnaissanceforthisLevel1Off-SiteDrainageAnalysiswasconductedonJanuary15,2015forthepurposeofanalyzingtheproposedprojectsiteanditsupstreamanddownstreamcorridors.Theweatherwascloudyduringthesitevisit.Duringthesiteinspection,therewasnoevidenceofstormwaterleavingthesite.31ConveyanceSystemNuisanceProblems(Type1)Conveyancesystemnuisanceproblemsareminorbutnotchronicfloodingorerosionproblemsthatresultfromtheoverflowofaconstructedconveyancesystemthatissubstandardorhasbecometoosmallasaresultofupstreamdevelopment.Suchproblemswarrantadditionalattentionbecauseoftheirchronicnatureandbecausetheyresultfromthefailureofaconveyancesystemtoprovideaminimumacceptablelevelofprotection.TherewerenoconveyancesystemnuisanceproblemsobservedduringtheAugust16,2013sitevisit.Furthermore,basedonareviewofthedrainagecomplaintsreceivedfromtheCityofRenton,thereisnoevidenceofpastconveyancesystemnuisanceproblemsoccurringinthedirectdownstreamdrainagecourse,asthereisarecordofnonehavingbeensubmitted.StormwaterrunofffromtheVuecrestIIprojectwillbeconveyedoffsitetothedrainagefacilityforVuecrestEstates,whichwillbesizedtoincludethefuturedevelopedsiteareafromtheVuecrestIIproject.Theoff-sitedrainagefacilitywillberequiredtoprovideBasicWaterQualityTreatmentandLevel3FlowControlforthedevelopedareasfromthisproject,followingthe2009KingCountySurfaceWaterDesignManual(KCSWDM).ProvidingLevel3FlowControlwillensurethatnodownstreamconveyancesystemnuisanceproblemsareaggravatedbytheproposedproject.3.2SevereErosionProblems(Type2)Severeerosionproblemscanbecausedbyconveyancesystemoverflowsortheconcentrationofrunoffintoerosion-sensitiveopendrainagefeatures.Severeerosionproblemswarrantadditionalattentionbecausetheyposeasignificantthreateithertohealthandsafetyortopublicorprivateproperty.StormwaterrunofffromtheVuecrestIIprojectwillbeconveyedoffsitetothedrainagefacilityforVuecrestEstates,whichwillbesizedtoincludethefuturedevelopedsiteareafromtheVuecrestIIproject.Theoff-sitedrainagefacilitywillberequiredtoprovideBasicWaterQualityTreatmentandLevel3FlowControlforthedevelopedareasfromthisproject,followingthe2009KingCountySurfaceWaterDesignManual(KCSWDM).Level2Flowcontrolisintendedtolimittheamountoftimethaterosiveflowsareatworkgeneratingerosionandsedimentationwithinnaturalandconstructeddrainagesystems.Level3Flowcontrolfurtherrestrictsthedownstreamreleaserateoftheproject’sdrainagefacilityintendedtopreventsignificantincreasesinexistingwatersurfacelevelsfor2-yearthrough100-yearreturnfrequenciesandpreventaggravationofexistingflooding.3.3SevereFloodingProblems(Type3)Severefloodingproblemscanbecausedbyconveyancesystemoverflowsortheelevatedwatersurfacesofponds,lakes,wetlands,orcloseddepressions.Severefloodingproblemsaredefinedasfollows:.Floodingofthefinishedareaofahabitablebuildingforrunoffeventslessthanorequaltothe100-yearevent.Examplesincludefloodingoffinishedfloorsofhomesandcommercialorindustrialbuildings.Floodinginelectrical/heatingsystemsand17254.001-TIRdoc componentsinthecrawispaceorgarageofahome.Suchproblemsarereferredtoas‘severebuildingfloodingproblems.”Floodingoveralllanesofaroadwayorseverelyimpactingasoleaccessdrivewayforrunoffeventslessthanorequaltothe100-yearevent.Suchproblemsarereferredtoas“severeroadwayfloodingproblems.”BasedonareviewoftheFEMAMap(Section1.0)theproposedsiteisoutsideofthe500-yearfloodplain,andthereisnoevidenceofseverefloodingproblemsencounteredduringourvisit.StormwaterrunofffromtheVuecrestIIprojectwillbeconveyedoffsitetothedrainagefacilityforVuecrestEstates,whichwillbesizedtoincludethefuturedevelopedsiteareafromtheVuecrestIIproject.Theoff-sitedrainagefacilitywillberequiredtoprovideBasicWaterQualityTreatmentandLevel3FlowControlforthedevelopedareasfromthisproject,followingthe2009KingCountySurfaceWaterDesignManual(KCSWDM).Level2Flowcontrolisintendedtolimittheamountoftimethaterosiveflowsareatworkgeneratingerosionandsedimentationwithinnaturalandconstructeddrainagesystems.Level3Flowcontrolfurtherrestrictsthedownstreamreleaserateoftheproject’sdrainagefacilityintendedtopreventsignificantincreasesinexistingwatersurfacelevelsfor2-yearthrough100-yearreturnfrequenciesandpreventaggravationofexistingflooding.17254.OO1-TIR.doc TASK4DRAINAGESYSTEMDESCRIPTIONANDPROBLEMDESCRIPTIONSPleaserefertothedownstreamdrainagesystemtableandmapincludedinthisSection.DrainagecomplaintswererequestedfromtheCityofRentonandareincludedinthissectionaswell.Therewereonlytwodrainagecomplaintsneartheprojectsite,andbothcomplaintswerefiledmorethan15yearsago.Thesecomplaintsdonotapplytothedownstreamdrainagecoursefromthisproject.17254.OO1-TIR.Uoc TASK5MITIGATIONOFEXISTINGORPOTENTIALPROBLEMSStormwaterrunofffromtheVuecrestIIprojectwillbeconveyedoffsitetothedrainagefacilityforVuecrestEstates,whichwillbesizedtoincludethefuturedevelopedsiteareafromtheVuecrestIIproject.Theoff-sitedrainagefacilitywillberequiredtoprovideBasicWaterQualityTreatmentandLevel3FlowControlforthedevelopedareasfromthisproject,followingthe2009KingCountySurfaceWaterDesignManual(KCSWDM).Level2Flowcontrolisintendedtolimittheamountoftimethaterosiveflowsareatworkgeneratingerosionandsedimentationwithinnaturalandconstructeddrainagesystems.Level3Flowcontrolfurtherrestrictsthedownstreamreleaserateoftheproject’sdrainagefacility,intendedtopreventsignificantincreasesinexistingwatersurfacelevelsfor2-yearthroughI00-yearreturnfrequenciesandpreventaggravationofexistingflooding.I7254.OO1-TIR.doc Basin:BlackRiverOFF-SiTEANALYSiSDRAINAGESYSTEMTABLESurfaceWaterDesignManual,CoreRequirement#2Distancet)bserationsofFieldInspector,LocationDrainageComponentDrainageComponentfromSiteExistingPotentialResourceReviewer,orIDType,Name,andSizeDescriptionSlopeDischargeProblemsProblemsResidentConstrictions.undercapacity.ponding,Type:sheetfloss.swale,stream,overtopping.floodmg,habitatororganismacipsep)deDass,hat,etatocoedectrh)senitbnk]osigIbtses1kelhoddphISeeMapdiameter,surfaceareadepth.typeofsensirivearea,volume%Ft.seditnenlation,incision.othererosionoverflowpathn’ays.potentialimpactsINaturalDischargePointforested0NoneNoneNoevidenceofflowingwaterAnticipated.durjngsiteinspection.RefertoPicture#1forphoto.I-2Swa]eHeavilyvegetated.SwaleNoneNoneTrickleflowatdownstreamwidthnarrowsasitcontinuesAnticipated.end.downstream.2Pipe12”DuctileIronPipeApprox.NoneNoneModerateFlow.Referto850’Anticipated.PictUre#2forphoto.2-3SwaleVegetagedIRocklinedswaleNoneNoneModerateflowApprox.2-4’wide.Anticipated.3BridgeCrossingPedestrianBridgeCrossingApprox.NoneNoneModerateFlow.Referto1,200’Anticipated.Picture#3forphoto.3-4SwaleRocklinedswaleNoneNoneModerateFlowApprox.2-4’wide.Anticipated.4Pipe12”pipecollectionpointApprox.NoneNoneModerateFlow.Referto‘/4mileAnticipated.Picture#4forphoto.I7254-Off-SiteAnalysisDrainageSystetnTahle.dor ,FPicture#1-LookingDownstreamfromNaturalDischargePoint[iture#3-Lookingupstreamfrompedestrianbridge.]IPicture#2-Lookingupstreamat12Dlpipecollectionpoint.Picture#4-Lookingupstreamatpipecollectionpoint. 11993-096532003-0475DRNGMNWFCR10/27/199311705/199318811104THPISE07/21/200308/05/200318839104THP1SE1778300060COUGARMEADOWS1778300290N/A(ooindownstream)]INIA(notindownstream)ComplaintRecNoProblemTypeRecdDateCloseDateAddressPINComments22002-0562MNWFCR07/31/200208/05/200218839104THPLSE1778300290REQUESTTOREMOVETANSYRAGWORTFROMPONDAREAInoUndowno2004-0720FRESUP09/21/200410/25/2004104THPLSEASE190THST1778300290REVISIONTOOUTFALLFROMD91882fNIA)notindownstream):2004-0720FRESUPF01/05/2005104THFLSE&SE190THST1775300290REVISIONTOOUTFALLFROMD91882NJA)oottodowostreamt61989-0727DRNGC11/08/198911/24/198919025104THPLSE2141270180WATEROVERFLOODEDR/DPOND59-0727N/A)notindownstream)71994-0955DRNGC12/22/199412/29/199410320SE186THST2641400090GROUNDWATERIMPACTTOCRAWLSPACEN’Anotindownstream)81995-0712PONDINGC08/29/199509/14/199510320SE186THST2641400090DRNGFROMADJACENTLOT(DOWNSPOUTS?)N?A)notndownstream)2000-0462DDMC06/22/200007/07/200010359SE187THFL2641400420WATERtNCRAWLSPACE.APPARENTPLUGGED4-N!Anotindownstream)INCHDIA.PJPE.PRIVATESYSTEMPRIVATEMAINTEANCERESPONSIBIL9Y.101996-0016C/BC01/08/199603/24/199710339SE187THPL2641400450PVTDRNGSYSCONCERNSELEVOFCBNIA)nottndownstream)111996-0817RETWALLFCR03/26/199604/18/199610335SE187THPL2641400460VANDALISMOFBLOCKRETAININGWALLN1A)notindownstream)122000-0209DUMPtNGWQC03/27/200005/15/200015725102NDAVESE2641400640PROPERTYOWNERDUMPINGLANDSCAPEDEBRISN/A131998-0647MAINTFCR09/24/199810/05/199810215SE186THST2641400640APPEARSPONDOKNOPEWILLNOTBECLEARENJA)nettndownstream)2001-0074BSRR01/19/200107/06/200110215SE186THST2641400640BIO-SWALERETROFITCATEGORYCCLOSETORETRN/A)rotindawneneam)142001-0467MMMFCR08/03/200108/24/200110215SE186THST2641400640MOWINGCREWSREQUESTEDPONDCLEANINGGROWTHTOOSUBSTA15NTIALFORMOWINGIN/A2004-0002MNMFCR01/05/200410215SE186THST2641400640TreesfallenfromprivatepropertyontoSWMtractandRoadROWTreespartiallycutbyneighborsforaccess.RDcontactedtoremoveremainingfromROW.WAfortreeremovalandfencerestora7°‘°16IN/A2004-0530MNMFCR07/12/200408/05/200415616102NDAVESE2641400640Blackberries/vegetationfromD92301tractgrowingoverfenceontocom17alainantproperty.N/A182004-0571MNMFCR07/13/200410215SE186THST2641400640FrogsN/A1919971589MAINTFCR12/11/199712/24/1997SEB6TH/O2NDAVESE2641400650CONCERNREMAINTRESPWETLANDISSUES2006-0567IREFCR05/29/200610/25/200610371SE157THFL2641400650TreesinD92301crackingsidewalk.WAtoremovetEenpriedrnntwRre20otace35-ftsectionsofsidewalk.IN/A211997-1384CULVERTC09/23/199710/17/19971B646100THSE3123059049WEETFLOWFROMPRIVATERDIMPPVTPROP222001-0817DDMC12/17/200112/31/200118819102NDAVESE3223059027APPARENTGROUNDWATERIMPACTTOLIVINGSPACEIN/Anotindownslrer231989-0672DRNGC10/23/198912/12/19591852B102NDAVESE3223059031BLKDEASMTN/A241999-0507DRAINAGEC07/07/199907/23/19991O3XXSE190THST3223059031FILLONLOTPRIORTOSFRCONSTRUCTIONN/A252005-0575DTAFCS10/01/200518808102NDAVESE3223059031f4/A)notindownstream) KINGCOUNTYWATERANI)LANDRESOURCESDIvIsioNDRAINAGEINVESTIbATIONREPORTPage1:INVESTIGATIONREQUEST_______DateqqOkabFILEoReceivedfrom:(Day)(NAME:&u-tDn)-.I*PHONE1SLDZ_______ADDRESS:Th5CityRefl+DflState____ZipD5ig1_,,,t‘Locationofproblcm;fdifferent77-ijr%j-1-/iJj>L1ReportedProblem:CALLFIRSTJ(WouldLikeToBePresent)-ThrL3-CeJ1Q4’tiM1V?6WhJMIkt&A1vMfVLS%irul.Ycc1JiyvttMro-ILn;Wtpt(tjsfyor-flL*LAJJC41i5&iOYAW&vbKJWoc(v3v;£V\3ttK5UItrrO%’*OWL1t1D7ISCY?J(F’I5e/((çIO,/AI.:n-tc;3r‘dL,r/A?,//k;Platname:Otheragenciesinvoh’ed:Nofieldinvestigationrequired(initials)r*zToBECOMPLETEDBYCOMPLAINTPROGRAMSTAFF‘s3’12’z5¼STRParcelNo.ItV‘4’7Kro11(5,Th.Bros:New/i24I’ZOld4(ESBasinCouncilDistrictChargeNo._________________________Leadagencyhasbeennotified:Problemhasbeencorrected._____‘c:’Privateproblem-NDAPwillnotconsiderbecause:Wateroriginatesonsiteandloronneighboringparcel.--LocationisoutsideWLRDServicDATECLOSED/7By_____PROBLEM:&%1v.t4’-bRECEIVEDBY:Type______(Eve)(‘kLC-t-&A4LotNo:BlockNo:RESPONSE:Citizennotifiedon//S?.by:Xphone.letter____inpersonaAL€LAJ_c:.446411ir’___L%(%L(LDISPOSITION:Turnedto____onIIby_____OR:Nofurtheractionrecommendedbecause:____Noproblemhasbeenidentified.—Priorinvestigationaddressesproblem:SEEFILEft________________Other(Specify): 1nvesthationDate:I()-7-97Parcel#3123t)59049MaintenanceDiv.RentonPatName:Imetwiththecomplainantatherhometodiscussherconcernsaboutthedrainageonaprivateaccessdrivefor8homes.1’hefirsttwopropertiesonthenorthsideoftheaccessdrivearelocatedwithinKConSE7thstreet(privateroad).South5thontheRentonsideoftheaccessroadalsoisaprivateroad.Waterrunsdowntheasphaltprivateaccessdriveonthecountysidedowntotherentonsideoftheaccessroad.ThewaterthanrunsdawnthedrivewaytoMrs.Buttonmobilehome.Mrs.Buttonwouldlikethecountytodosomethingaboutthedrainageontheaccessroad.IexplainedtoherthattheCountydoesn’tmaintainprivateaccessroadsorthedrainageonthem.Shewasalsoconcernedaboutaconcretepipeacrossthestreetthatwascracked.Thispipeisadrivewayculvertandtheownerpunchedaholeinthetopofthepipeandinstalledayarddrain.Noproblemwiththeconcretepipe.Allconcernsareconsideredaprivateproblem.Itoldher1wouldstillscreenthecomplaintandcallheriftherewasanychangeintheinvestigation.ei;ngCounty:Name:AlButton‘Comvlaint#97-1384‘DepartmentofNaturalResourcesRecei\ed9-23-97...Address:71)south)t*StWaterandLandResourcesI)ivistonAssined1)ate9-’t)-97LocalDrainageServicesUnitCityrenlonStatevaZip98()55ReportI)ateI0-8-97-ih()masI3ros.686I2Phone:Day25-6289STR,l-23-5BasinbikCouncil1)1st.6InitialsdcdPhone:EveniiJacility#,I•hNEWSFSUNDERCONST.YARDDRAINI—BUTTON7I5102NDAVESECITYOFRENTONKINGCOUNTY (f4,KingCountyDepartmentofNaturalResourcesWaterandLandResourcesDivision700FifthAye,Suite2200Seattle,WA98104-5022AI7(LLJDETACHHERE.&i_,,:.,-:.t’•:‘WJO!JI3Complaint#3’2/S’1Pleasetakeamomenttofilloutthissurvey.Yourinputwillhelpusimproveourcustomerservice.IWereyouabletoconvenientlyreachtherightpersonatWaterandLandResourcestoassist.CYESDNOyou?2.Oncethecomplaintwastaken,didstaffclearlyexplainhowyourcomplaintwillbehandledDYESDNOandwhattoexpect?1-3.Duringourinvestigationofyourcomplaint,wereyousatisfiedwithhowwellyouwerekeptDYESDNOinformed?4.Duringourinvestigation,didwemeetouragreement/commitments?DYES-DNO5.Wasthestaffprofessionalandcourteous?DYESDNO6.Overall,howdoyoufeelaboutourperformanceinvestigatingyourcomplaint?Name:(Optional)Phone:_________________ COMPINTYPROBLEMTYPEOFNEWNUTThERPEADI)RESSPROBLEMCDTTNENTSTNER75-oo(;6C82-0183C86-03A7C88-0130XI9225100341860019219SPRINGBROOKSE190THSTTALBOTRD102NDAVERDSPONDFLOGSEFLDGSEDRNG686B2686B2686B2686B2686B290-1610C730S55THSTMUDDYCONDITIONINRENTON@PARKRIDGEEAST/OVERFLOWANDEROSIONFLOGEROSION?SLIDE/HOUSECONST a+S7-?? 97-/1t4asa:a ci?./67%3bjI aJ:f%1:sq“4F-- c1’/bL,i.;NDczI-c_f’LgrOt),oD-IC)-Lt1,‘I_\A/‘t::‘c)1)0> Ij4o*qzsavij3l1stS;14HL6Z3SW2>3SIWzEz3%—;;,-.INUZZ$IS-).IS-_)$__Sz35;4.(L4L43$;dNLO—1rJf!35IS1fi-iE.“..‘..%c:;r_nz1tI‘::[—\jL_IJr‘z:ir_:.-—i1I‘is:IV--F:‘-—-I---‘:!‘.(:‘.I3i:?•—:-i..Iis—tiuiI:—•IktI—\_6f1.,II—j3-;_5inuiLx‘I—‘•.I--•s[—.—...\--cNI-T--3•1-I;:;r!i-%1S(JHI)1Is“I.‘-is—r‘——%A;h\;SH3YWIJN3V\1.:J3oc2sSiHLi/rI!gEINDU.iL?\sr--rmn14N‘m___•HI*Z35\;Ej5LLAL,bgrrLfc4;-:::ILtwL11rtLHUN3S8irI-i—i_sHIZIZ35+Ic5L,fT3ISLSHIUZHIt113i-]4iI:NtN411EH4c,5kt1i.LS$iuEisIzHL9EZSc?f4JHLZJEEH18O4kHJINJ3Js33H1t”H14NVdiNvJ1dN1N1,35HILU3S1IrI:;-ç‘pV‘H:IHrI”’’;;ip14“I:15L6OZSii—r-i-ii’--\“VHi:zot-S_tGS:rjV,-J\—,9Hj.,‘‘-“‘-,—-y;iAUVSis:‘LLtiNv1,_‘:‘cfc6(IISRir-•—--I—n————-H1961SSiWX!ISI?::IL17AY7“M<),:[.-L\Iisft—-.—“‘.ZL,1’.-:;-H—r---N-H11HtsjJ11HÜtISILS1HSIISIC’SIs—-UNbtisSlut35:35;‘(‘:.:tf:N1::::‘iooqt’INj4Th61h53Hd1H4jHS1HS’crvdI_-\-SSSz:‘,LSIHHLlSf_(__:th*2>::1‘H)U‘>HugIiI1I!it-:t-I-HtF-j-_--_--HH>i—__JI_flISHU99535is_:1!r1—EiHIk8IhSifr1rilSIi;s;.UHCSL3S,,_-v‘-1LiiLJC,)F_flSI.sL19-.,.,IkI1’.H:iN]wPz54,ç:“l.*’%Z4i/:jrU-jjISHIPHI35);—--989“.,.,.:J\:L-‘‘-:33S’_Q-—_%fa1IcVs!‘y“r C,,.00000CD.I P<’I.C CD 3GQ •.1‘‘<-3 c1 CD“CDNt%1 0cr cih.;;0rD c:-0 4CDCDa 0F\JjgQCD %rCDre%%r4.“IQ0%-‘•1(..•Nr.Cz0 (tgzCDbT1i.,\rrl::I I9.. cciIg \4 hi 0CDC,,CD 0 J %\\cL c(%(I.I1‘I‘;0?.Z1 L\2rt ‘S Nc::%%\-r •% . ç%%\ N N I h f az z00 w (Pc-> 00ri0]II CD 0 c,•tZc H CD •N __ _‘_\ ‘c \ ‘\ •@1:::!)KingCountyDepartmentofNaturalResourcesWaterandLandResourcesDivi’ion700FifthAye,Suite2200Seattle,WA98104-5022DETACHHERE....,.....;;..r):..HOWISOURCUSTOMERSERVICE?.Complaint#VPleasetakeamomenttofilloutthissurvey.Yourinputwillhelpusimproveourcustomerservice.I.WereyouabletoconvenientlyreachtherightpersonatWaterandLandResourcestoassistDYESDNOyou?2.Oncethecomplaintwastaken,didstaffclearlyexplainhowyourcomplaintwillbehandledDYESCNOandwhattoexpect?3.Duringourinvestigationofyourcomplaint,wereyousatisfiedwithhowwellyouwerekeptDYESCNOinformed?4.Duringourinvestigation,didwemeetouragreement/commitments?DYESDNO5.Wasthestaffprofessionalandcourteous?DYESDNO6.Overall,howdoyoufeelaboutourperformanceinvestigatingyourcomplaint?//Name:(optional)Phone:_________________j IfyouhavenotbeencontactedwIthin,feelfreetocall_-_at______________________,ourcomplaininvestigationline,296-1900ortollfreeat800/325-6165(KingCountyInformationwilltransferyou).Yourcomplaintwasclosed(inpersonoronthephone)on1a/ty7bycAJt:%:POSTAGEWILLBEPAiDBYTHEADDRESSEEKINGCOUNTYDEPTOfNATURALRESOURCESWATER&LANDRESOURCESDIVISION700fIfTHAVE,SUITE2200SEATTLE,WA98104-9898ATTN:LARRYGETTLE,SENIORENGINEERiP;.--±OMPLAINTINVESTIGATIONSTATUSAI3D1:,4...--.,fi-ComplaintNumber:DateReceived:17OneofKingCounty\VaterandLandResourcesDivision’sservicesistoprovideacontactfordrainageandwaterqualityconcernsandproblems.Citizensassistusbyinforminguswhentheynoticethesetypesofprohlems.TheLocalDrainageServicesUnitwillinvestigateanddetenincresponsibilityfortheproblem,refercomplaintstotheappropriategrouporagency.anddirectcustomerstoothersourcesofassistanceforproblemsoutsidetheagency’sscopeofresponsibility.Toensureproperreferral,weconductedaninitialreview/fieldinvestigationofyourcomplainton/1/1/97.STATUS.r:Requiresfurtherreviewbyanengineertodetermineproperreferralorresolution/closure.Wasreferredto:DKingCountyDepartmentofCKingCountyRoadsDevelopmentandEnvironmentalServicesOther-ReferralContact:‘,,4C4r(1)2’71’?1appreciateyourpatience...Duringsevererainstorms,wereceiveanunusuallyhighvolumeofdrainagecomplaints.Althoughweassignadditionalstafftohandlethesecalls,youmayexperienceadelayinresponsetoyourcomplaint._,KEEPTHISCARDFORYOURRECORDS-------------------------------[[H___[TEDSTATESBUSINESSREPLYMAILFIRSTCLASSMAILPERMITNO.1179SEATTLE,WAIIiIiiIiiIiiiiIIItinitiiItsI,tIiiIiIil.1I1iI1i!jiII COriPLNTYPROBLEMTYPEOFNEWNUT1BERPEADDRESSPROBLEMCOMMENTSTNBRWINDSORFIGHTSDEVELOPMENTCOUGARMEADOWSDETERIORATINGPVTROADINFOTODENTALOFFICEGROUNDWATERIMPACTTOCRAWLSPACEOBSTRUCTEDFLOWBYFREDRICK’SPLACE??NOEVIDENCEOFHERBACIDEAPPLICATIONALLEDGEDDRAINAGEFROMPLATIMPACTPROPALLEGEDDRAINAGEFROMPLATIMPACTPROPPVTDRNGSYSCONCERNSELEVOFCBPRIVATEPROPERTYIMPACTSFROMADJDEVPRIVATEPROPERTYIMPACTSFROMADJDEVSHEETFLOWSPREADERIMPACTNEIGHEORHOODSHEETFLOWSPREADERIMPACTNEIGHBORHOODSHEETFLOWGRNDWATERIMPACTPVTPROPVANDALISMOFBLOCKRETAININGWALLD/SNEIGHBORWILLMAINTAINMAINTENANCEACTIVITYRIDPONDOBSTRUCTEDDRAINAGEPVTPROPIMPCONCERNREPONDSIDESLOPESMEETSSTANDSHEETFLOWIRONOXIDEDISCHARGEOVERSWPVTPIPEINSTALLINEASEMENTPVTREPAIRAPPEARSTOBEACTIVECLEARINGPROJ93-0084C102AV@187STINQ93-0965C18811104THPDSEDRNG94-0133C92%398THPLSEROSION94-0529WQC4300TALBOTRDSWASHING94O955C10320SE186THSTDRNG94-0995C18616102NDAVESEFLOODING95-0550WQCSE104TH&192NDASEHERBICID95-0770C18862103RDCTSEDRAINAGE95-0770F18862103RDCTSEDRAINAGE96OO16C10339SE187THFLC/B96-0104C18616102NDAVESERUNOFF96-0104R18616102NDAVESERUNOFF96-0146FCR18808102NDAVESEPOND96-0146R18808102NDAVESEPOND96-0701C10320SE194THSTDRNG96-0517FCR10335SE187THPLRETWALL96-1259R18862103RDCT.SEEASEMENT96-1332FCRl8$51103RDCT.SERIDPOND97-0600C19121104THPLSEDRAINAGE97-0758C1921598THAVE5,#EDRAINAGE97-1107WQC1922398THPLSIRONOXID97-1213C18862103RDCTSEPIPE97-1239WQC18600102NDAVENEDUMPING686C2686C2686C2686C1686C2686C1686C2686C2636C2686C26$6C1686C1686C2686C2686C26$6C2686C2S86C2686C2686C2686C26$6C2686C1 11Ac!:::!frt_::iLL1’jcAje,.1’T,.•rC‘-ItfLN%I4L&:___.-—-—---*-IsiB%TH$7f.V,F’‘t4*fl1’\I;*,I’fI‘%?-:s:.r_-%t,.!7/4%J;—‘I\Th;:1.:‘;-.Ir’.c‘‘e.1:’,A4%a*tL-:56’iii4’2’r:CLt.tt._:“,j€I1LiçrsJ“:z”-:4sVa;g%4HJr!t”I.$rI1:_1:eJc&((J_9,47;:‘mt%,L2:.;/3,3:I3.s;©:4:1.)a:••.kç*JJ.‘,,‘r.itt;>—AeN%):_2n_%--r‘.‘%-‘r.(.---.4’-‘1-‘--r‘Irnt‘1%CL:ftr:‘;L./?..SEIE7IH:<:1N.4Q.,L-g::;‘I:.‘.‘,t?4.CCS’•i.J%fl(J;4TtD,-%_r_-.7A)Jr1/r-.#,1‘yt_An_____________—.—.—.4’$%‘4%r.;<,,k:‘-;IJ-*qTrhqrLfl’j.‘L1L.: ccGDcc.,‘..“‘.KN&T;;oSEEkkP_____________iLriT___—\/\[\[___I-----—--——,‘“----zH4/4:iaI3SAVQESt“w’,tczr—voNf;z%--;::t;;•%A-V.)ft’-1SRLtI_3SAYRt)StSv;ot‘—iV:,,—:1’;::cKti,;:c’3S,;?-AYoor)E__:_11%1LSj;;;fr’)i•:c:jwRLc;.AY!I—!cr:i3-zr-iiaoctc:F3SAITtAyzH1JyHi8tT;tI!r[;L:4t—L’;:1G1i--ft:djçv!)1!qirs:i3Si_ii\3S1dHLHLOtI_-::---..:r:i--:.£•j:ILj1:flThoii’::z—‘;_-AIFFFF—-—--a.—ji:;:dpot:çifcldr-_-I?P-4::°!‘dattIAvic:LTHERS1-rS7dr_I(I:ç‘%S!?1;rAVuoo1r/;1•;f%iifN—.41;_--4—__4j___fATJimITI.Gf6-co%‘J’‘‘ld;1sAY1uv6Ar3y11f9661fiThAUJJ-‘---dW‘.‘J31S4r1).;b4fl1r—r’.r11-_w;;:::EISHH’6‘di6‘b( LEVELTWODOWNSTREAMANALYSISforVUECRESTESTATES4800BlockofSmithersAvenueSouth,Renton,WashingtonDRSProjectNo.12102RentonFileNo.LUAI3-000642Owner/ApplicantHarbourHomes,LLC1441North34thStreet,Suite200Seattle,WA98103ReportPreparedbyD.R.STRONGConsultingEngineers,Inc.10604N.E.38thPlace,Suite232KirklandWA98033(425)827-3063ReportIssueDateMay21,2013ReportRevisionIssueDateSeptember28,2015©2015D.R.STRONGConsultingEngineersInc. LEVELTWODOWNSTREAMANALYSISVUECRESTESTATESTABLEOFCONTENTSTASKIDEFINEANDMAPTHESTUDYAREAITASK2RESOURCEREVIEW5TASK3FIELDINSPECTION16UpstreamTributaryArea16GeneralOnsiteandOffsiteDrainageDescription16TASK4DRAINAGESYSTEMDESCRIPTIONANDPROBLEMDESCRIPTIONS...17DrainageSystemDescription17DownstreamPathI7NDAI17NDA217ProposedDownstreamPathandAnalysis17TASK5MITIGATIONOFEXISTINGORPOTENTIALPROBLEMS22AppendixA.BasinReconnaissanceProgram23AppendixB.DownstreamSystemBackwaterAnalysis24ListofFiguresFigure1VicinityMap2Figure2SiteMap3Figure3KingCountyiMapTopography4Figure4Streamsand100-YearFloodplainsandFloodway6Figure5KingCountyiMapWetlands7Figure6CityofRentonErosionHazardAreas8Figure7CityofRentonLandslideHazardAreas9Figure8KingCountyiMapSeismicHazardAreas10Figure9FEMA—FloodInsuranceRateMap11Figure10KingCountyiMapDrainageComplaints12Figure11USDAKingCountySoilsSurveyMapI3Figure12DownstreamMap19Figure13DownstreamTable20©2015D.R.STRONGConsultingEngineersInc.PageiofiLevelTWODownstreamAnalysisVuecrestEstatesCityofRenton TASKIDEFINEANDMAPTHESTUDYAREAThisOffsiteAnalysiswaspreparedinaccordancewithCoreRequirement#2,SectionI.2.2ofthe2009KingCountySurfaceWaterDesignManual(Manual).TheSiteislocatedatthe4800BlockofSmithersAvenueSinRenton,Washington.SeeFigure1,Figure2,andFigure3formapsofthestudyarea.©2015D.R.STRONGconsultingEngineersInc.Page1LevelTWODownstreamAnalysisVuecrestEstatescityofRenton FIGURE1VICINITYMAP©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage2CityofRentonTheinformationincludedonthismaphasbeencompiledbyKingCountystafffromavarietyofsourcesandissubjecttochangewithoutnotice.KingCountymakesnorepresentationsorwarranties,expressorimplied,astoaccuracy,completeness,timeliness,orrightstotheuseofsuchinformation.KingCountyshallnotbeliableforanygeneral,special,indirect,incidental,orconsequentialdamagesincluding,butnotlimitedto,lostrevenuesorlostprofitsresultingfromtheuseormisuseoftheinformationcontainedonthismap.AnysaleofthismaporinformationonthismapisprohibitedexceptbywrittenpermissionofKingCounty.VuecrestEstates FIGURE2SITEMAP©2015D.R.STRONGConsultingEngineersInc.Page3LevelTWODownstreamAnalysisVuecrestEstatesCityofRenton o ——- 9c -----‘A c _;o0(4u1:Y •00000 C[.OC C CC o’ ----C —C êCoø0Ø0O0 I 0GEkØC::3o::°o% 4O FIGURE3KINGCOUNTYIMAPTOPOGRAPHY1—IxHighlightedFeatureCountyBouødaryMountainPeakscontours(5ffdark)OthvrF]Parcels©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage4CityofRentonLegendH1ghwaysStreets::LakesandLargeRivers3?v’StreamsVuecrestEstates TASK2RESOURCEREVIEW.AdoptedBasinPlans:Noneatthistime..Floodplain/Floodway(FEMA)Map:The500-yearfloodplainand100-yearfloodplainwithaveragedepthsoflessthan1-footexistonsite,SeeFigure9..OtherOffsiteAnalysisReports:OtherOffsiteAnalysisReportsincludeCampenSpringsCondominiumsandBorgataApartmentsandTownhomes..SensitiveAreasFolioMaps:SeeFigures4-8fordocumentationofthedistancedownstreamfromtheproposedprojecttothenearestcriticalareas.Included,aresectionsoftheKingCountySensitiveAreasFoliowhichindicatethefollowing:.Figure4Streamsand100-YearFloodplainsandFloodway:Thereisa100yearfloodplainwithinonemileoftheSitealongthedownstreampath..Figure5Wetlands:TherearemappedWetlandsthatexistsonsite..Figure6ErosionHazard:TherearemappedErosionHazardAreaswithinonemileoftheSitealongthedownstreampath..Figure7LandslideHazard:TherearemappedLandslideHazardAreaswithinonemileoftheSitealongthedownstreampath..Figure8SeismicHazard:TherearenomappedSeismicHazardAreaswithinonemileoftheSitealongthedownstreampath..DNRPDrainageComplaintsandStudies:AsshowninFigure10,therearenodrainagecomplaintswithinImileoftheSitealongthedownstreampath..RoadDrainageProblems:Nonenoted..USDAKingCountySoilsSurvey:SeeFigure11..WetlandsInventory:Vol.2South(1990)—Thewetlandinventoryrevealednoadditionalwetlandswithinthedownstreampath..MigratingRiverStudies:Noneareapplicabletothesite..WashingtonStateDepartmentofEcology’slatestpublishedCleanWaterActSection303dlistofpollutedwaters:Nonelistedalongthedownstreampath..KingCountyDesignatedWaterQualityProblems:Noneatthistime..AdoptedStormwaterCompliancePlans:Noneapplicabletothissite..BasinReconnaissanceSummaryReports:AreportisavailablefortheBlackRiver8am.SeeAppendixAforacopyofthisreport.©2015D.R.STRONGConsultingEngineersInc.Page5LevelTWODownstreamAnalysisVuecrestEstatesCityofRenton FIGURE4STREAMSAND100-YEARFLOODPLAINSANDFLOODWAY©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage6CityofRentonLegendSAOStreamHighlightedFeatureICOUntYBoundarYxMountainPeakHighway5Streets-Parcelsbc*ICbs*2PinsCIas2SmoCtass3Undawfj.dLakesandLargeRiversStreams100YearFloodplainVuecrestEstates At1nLocParcelsLakesandLargeRiversStreamsSAc,Wetland©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage7CityofRentonFIGURE5KINGCOUNTYMAPWETLANDSHighlightedFeatureI—_ICountyBoundaryxMountainPeaksHighwaysStreetskghy(cont)VuecrestEstates RentonCityLimitsEducationFireStationsPoliceDepartmentValleyMedicalCenterFIGURE6CITYOFRENTONEROSIONHAZARDAREASP/1_SITE-ThI—9#II’s*SeverityHighLEGENDErosionHazardPage8CityofRenton©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisVuecrestEstates RentonCityLimitsEducationFireStationsPoliceDepartmentValleyMedicalCenter©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisLandslideHazardSeverityVeryHigh.HighMModerateUnclassifiedPage9CityofRentonFIGURE7CITYOFRENTONLANDSLIDEHAZARDAREASLEGENDar9“S*VuecrestEstates ParcelsE1LakesandLargeRivers/v/StreamsSAOSeismicFIGURE8KINGCOUNTYIMAPSEISMICHAZARDAREASLoca’HghlightedFeatureI-_ICountyBoundaryxMountainPeaksH1gtiwaysStreetsF•’Hçhwzy(cont)©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage10CityofRentonVuecrestEstates UOWdJoADDO6edsieisIS8JO8flAS!SAIeUVW8J1SUMOGOMJIOAel‘oulSJ8aU!6U6u!jlnsuo3DNOd±Sdci9O©1P‘94’aNOZ‘P’(it:N;W()LJF’iiL’‘II‘‘‘I’.4V%’()‘‘I“.I:.•1xip.‘,;w.:ptlsXNOZSVjj’(IO()1JN]ftIO‘1;J)LNIs\Nk\C])C)I]‘“F’1P’‘‘3g\3NOZ.‘i)A3NOZ*f)%(l(‘p(i1•66VINOZ1)q’p‘I,II“lY’‘3d.ji.4%lPb1NOZLtJ.I,qIHV3NOZj)I$t’63NOZ‘VNOl(lt)f).1j\’Ik)‘it(1]1(NNils\1NV1N\-Z\HCfl(ii1\1j14sCIN]DEI1dvIj’J]IVN33NVNflSNIaOOii-63NflOLI FIGURE10KINGCOUNTYIMAPDRAINAGECOMPLAINTSParcei*Lakes3ndLatQR1vnStreamsDrswiageC*mti1aLegendSolactedPircals,l_CountyBoundaryxMotH1tanPeaksH•iWiwaysIncorporatedAreaAStreets//cont©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage12CityofRentonVuecrestEstates MapUnitSetting.Elevation:50to800feet.Meanannualprecipitation:25to60inches.Meanannualairtemperature:48to52degreesF.Frost-freeperiod:180to220daysMapUnitComposition.Alderwoodandsimilarsoils:95percent.Minorcomponents:5percentDescriptionofAlderwoodSetting.Landform:Moraines,tillplains©2015D.R.STRONGConsulUngEngineersInc.Page13LevelTWODownstreamAnalysisCityofRentonFIGURE11USDAKINGCOUNTYSOILSSURVEYMAPAgC—Alderwoodgravellysandyloam,6to15percentslopest.&\ZVuecrestEstates .Parentmaterial:BasaltillwithsomevolcanicashPropertiesandqualities.Slope:6to15percent.Depthtorestrictivefeature:24to40inchestodensicmaterial.Drainageclass:Moderatelywelldrained.Capacityofthemostlimitinglayertotransmitwater(Ksat):Verylowtomoderatelylow(0.00to0.06in/hr).Depthtowatertable:About18to37inches.Frequencyofflooding:None.Frequencyofponding:None.Availablewatercapacity:Verylow(about2.5inches)Interpretivegroups.Farmlandclassification:Farmlandofstatewideimportance.Landcapability(nonirrigated):4s.HydrologicSoilGroup:BTypicalprofile.0to12inches:Gravellysandyloam.12to27inches:Verygravellysandyloam.27to60inches:VerygravellysandyloamMinorComponentsNorma.Percentofmapunit:Ipercent.Landform:DepressionsBellingham.Percentofmapunit:Ipercent.Landform:DepressionsSeattle.Percentofmapunit:Ipercent.Landform:DepressionsTukwila.Percentofmapunit:Ipercent.Landform:DepressionsShalcar.Percentofmapunit:Ipercent.Landform:Depressions©2015D.R.STRONGconsultingEngineersInc.Page14LevelTWODownstreamAnalysisVuecrestEstatesCityofRenton AgD—Alderwoodgravellysandyloam,15to30percentslopesMapUnitSetting.Elevation:50to$00feet.Meanannualprecipitation:25to60inches.Meanannualairtemperature:48to52degreesF.Frost-freeperiod:I$0to220daysMapUnitComposition.Alderwoodandsimilarsoils:100percentDescriptionofAlderwoodSetting.Landform:Moraines,tillplains.Parentmaterial:BasaltillwithsomevolcanicashPropertiesandqualities.Slope:15to30percent.Depthtorestrictivefeature:24to40inchestodensicmaterial.Drainageclass:Moderatelywelldrained.Capacityofthemostlimitinglayertotransmitwater(Ksat):Verylowtomoderatelylow(0.00to0.06in/hr).Depthtowatertable:About18to37inches.Frequencyofflooding:None.Frequencyofponding:None.Availablewatercapacity:Verylow(about2.5inches)Interpretivegroups.Farmlandclassification:Farmlandofstatewideimportance.Landcapability(nonirrigated):4e.HydrologicSoilGroup:BTypicalprofile.0to12inches:Gravellyashysandyloam.12to27inches:Verygravellysandyloam.27to60inches:Verygravellysandyloam©2015D.R.STRONGconsultingEngineersInc.Page15LevelTWODownstreamAnalysisVuecrestEstatesCityofRenton TASK3FIELDINSPECTIONUPSTREAMTRIBUTARYAREAInevaluatingtheupstreamarea,wereviewedKingCountyIMAPaerialtopographyandimageryandconductedfieldreconnaissance.WeconcludedthattheupstreamareadoesnotdraintothedevelopableareaoftheSite.AportionofthepropertieseastoftheSiteappeartodraininaneasterlymannertowards102ndAvenueSE.ThewesternportionappearstodraintowardstheSite,howeverisinterceptedbythetwoonsitewetlandsanddoesnotreachthedevelopableSite.Thisareaisapproximately6.34acres.PropertiestothenorthdrainwesterlynotencroachingtheSite.PropertiestothesouthdrainssoutherlyawayfromtheSite.GENERALONSITEANDOFFSITEDRAINAGEDESCRIPTIONThetotalparcelarealessthesteepslopeswhichencumberthewesternhalfisapproximately6.05acres;2.10acresofwhichisencumberedbywetlandandopenspacetracts.Forpurposesofthisreport,the6.05acreswillbeconsideredthe“Site”.TheSitetopographyslopesfromtheeastofthesitetothewest.Thevegetationconsistsoftreesandmoderateunderbrush.TheSitecontainstwoNaturalDischargeAreas(NDA)whosedownstreampathsconvergewithinone-quartermileandarethereforecontainedwithinoneThresholdDischargeArea(TDA).NDAIAportionofSiterunoff(2.84acres,0.90developable)travelswesterlyandflowsofftheSite,throughavegetatedchannelnearS50thStreet,andeventuallyintoaconveyancesystemwithinTalbotRoadS.NDA2RunofffromtheremainderoftheSite(3.21acres,3.08developable)sheetflowsdownthesteepsleepandintotheconveyancesystemwithintheCampenSpringsCondominiumdevelopmentbeforeenteringtheconveyancesystemwithinTalbotRoadS.©2015D.R.STRONGConsultingEngineersInc.Page16LevelTWODownstreamAnalysisVuecrestEstatescityofRenton TASK4DRAINAGESYSTEMDESCRIPTIONANDPROBLEMDESCRIPTIONSDRAINAGESYSTEMDESCRIPTIONThedownstreamanalysisisfurtherillustratedanddetailedintheDownstreamMapandDownstreamTablelocatedinAppendixA.ThedownstreamareaislocatedwithintheDuwamish-GreenRiver;morespecificallytheBlackRiversubbasin.Thedownstreamareawasevaluatedbyreviewingavailableresources,andbyconductingafieldreconnaissanceonFebruary13th2013underovercastconditions.DownstreamPathNDAJRunofftravelswesterlythroughthesiteandappearstochannelizeaswithinthesteepslopeareabeforeenteringadefinedchannelontheneighboringpropertytothesouthwest.RunoffflowsthroughaductileironpipewhichappearedtobepartiallyblockedbeforeenteringamanicureddrainagechannelheadingwesttowardsTalbotRoadSouth(±800’).RunoffcontinuesthroughaseriesofpipesandcatchbasinsinasoutherlydirectionwithinTalbotRoadSouthuntilitteesintoan18”LCPEpipe(±1365’)whichconveysrunoffwesterlyintoaheavilyvegetatedarealocatedwithintheSpringbrookApartmentsdevelopment,westofTalbotRoadSouth(±1405’)NDA2Runofftravelswesterlyassheetflowacrosstheon-sitesteepslopearea.RunoffeventuallyentersaseriesofbirdcagestructurecatchbasinsontheCampenSpringspropertyandisconveyedwestthroughthepropertyviaaconveyancesystemconsistingofcatchbasins,twelveinchpipesandthedevelopmentwaterfeature.RunoffeventuallydischargesintoawetlandmitigationareajusteastofTalbotRoadSouthbeforeitcontinuessouththroughtheconveyancesystemwithinTalbotRoadSouth.RunofffromNDA2convergeswithrunofffromNDAIinfrontoftheBorgataApartmentsproperty(±1250’).ProposedDownstreamPathandAnalysisTheproposeddetentionfacilitywilldischargeviaanabovegroundHDPEpipewhichwillconnecttoCBNo.14oftheCampenSpringsconveyancesystem.Theconveyancesystemeventuallydischargestotheproject’ssoutherlydetentionfacilitybeforedischargingtothesoutherlywetlandmitigationareaandouttoTalbotRoadSouth.Perthe“DrainageReportforCampenApartments”preparedbyDaley-Morrow-Poblete,Inc.datedFebruary6,1998,theCampenSitegeneratesatotalof6.97cfsinthe100-year,developedcondition.ThereareessentiallytwoconveyancesystemswithintheSite,northandsouth,thataremirrorimagesofoneanotheranddraintotwoseparatedetentionfacilities;oneforthenorthernportion,theotherforthesouthernportion.Perthereport,facilitysizingwasperformedfortheentiresite,andthentherequiredvolumewassplitbetweenthetwodetentionvaults.Giventhetotalsitegeneratedrunoffof6.97©2015D.R.STRONGconsultingEngineersInc.Page17LevelTWODownstreamAnalysisVuecrestEstatescityofRenton cfs,itwasassumedthat3.5cfsisconveyedthrougheachconveyancesystem.100-yeardischargefromtheVuecrestEstatesDetentionFacilityis0.444cfs.Abackwateranalysiswasperformedwiththefollowingassumptions:.Dischargerateof4.00cfsthroughtheentiresouthernconveyancesystem;andThe.TailwaterElevationofthetopoftheriserwithintheCampenSpringsSouthernVault,El.185.5ThesearebothextremelyconservativeassumptionsgiventhefactthatdischargefromtheCampensitewouldonlybe3.5cfsattheinlettothevaultandwouldgetincrementallysmallerasitisanalyzedupstream.Further,toassumea100-yearTailwaterElevationforananalysisofthe100-yearstormthroughtheconveyancesystemessentiallyassumesastormof100-yearintensityfor48hourswherethevaultfillsuptothe100-yearstageinthefirst24hoursandtheconveyancesystemwouldcontinuetoconveyanother100-yearstorminthesecond.AppendixBcontainsthebackwaterspreadsheetandmapsaswellastheanalysisresults.Itwasfoundthatwiththeseconservativeassumptions,theadditionoftheVuecrestEstates100-yearpeakvaultdischargewouldincreasetheheadwaterwithintheconveyanceamaximumof3inches,whichdoesnotappeartocreateanynewdownstreamproblemswithinthesystem.Theconveyancesystemdownstreamofthedetentionfacilitywasquantitativelyanalyzed(uniformflowanalysis)usingamaximumvaultdischargeflowof3.75cfs.Thepipesdownstreamare12-inchminimumdiameter,smoothwallpipewithaminimumslopeofIP55%.Capacityofa12-inch,smoothwallpipe(n=0.012)withaslopeofI.55%isapproximately4.81cfs.Negligibleimpactstothedownstreamsystemareexpected.©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage18CityofRentonC:UserAMAJ1.DRS\Desktap\KCRTSF’4\FM.EXfIConnent:.Jannin9’SSolvePoiDiameter.......SlopeManning’sn....DischargeDepthPullElowCapacityI.O4_81ft/ftSftUelocityFlowAreaCFiticalSlopeCriticalDepthPercentFull..FroudeNumber.PullCapacity.QMAX.94D..vuecrestEstates FIGURE12DOWNSTREAMMAP©2015D.R.STRONGConsultingEngineersInc.Page19LevelTWODownstreamAnalysisVuecrestEstatesCityofRenton [-—Lzz__0—------__GRAPHICSCALE NDAIFIGURE13DOWNSTREAMTABLESymbolDrainageDrainageComponentSlopeDistanceExstingPotentialObservationsoffieldinspectorComponentType,DescriptionFromsiteProblemsProblemsresourcereviewer,orresidentName,andSizeDischargeType:sheetflow,swale,drainagebasin,vegetation,constrictions,undercapacity.ponding,tributaryarea,likelihoodofproblem.SeemapStream,channel,pipe,cover,%114mil,320ftovertopping,flooding,habitatororganiamoverflowpathways,potentialimpacts.Pond;Size:diameterdepth,typeofsensitivearea,destruction,scouring,banksloughing,Surfaceareavolumesedimentation,incision,othererosionANaturalDischargePointchannelflowacrosssouthwest±0’NoneObservedNoneAnticipatedpropertycornerA-BSouthwesterlychannelTrapezoidalchannel:0.5’Deep,±180’NoneObservedNoneAnticipatedTrickleFlowFlow3’widetaperingto1‘wide,heavilyvegetatedB-cSouthwesterlyPipeFlow12”DuctileIronPipe(DIP)toa±225’NoneObservedNoneAnticipatedTrickleFlowatOutletditchc-DWesterlychannelFlowTrapezoidalchannel:i’Deep,4’±695’NoneObservedNoneAnticipatedModerateFlow,WaterVDeepwide,heavilyvegetatedD-ENorthwesterlyPipeFlow12”LCPEPipetoaType1CB±740’NoneObservedNoneAnticipatedModerateFlowE-FWesterlyPipeFlow72”LCPEPipetoaType1cB±800’NoneObservedNoneAnticipatedModerateFlowF-GSoutherlyPipeFlow12”DIPtoaTypeICB±1,015’NoneObservedNoneAnticipatedModerateFlowG-HSoutherlyPipeFlow12”LCPEPipetoaType1CB±1,05D’NoneObservedNoneAnticipatedModerateFlowH-ISoutherlyPipeFlow12”LCPEPipetoaType1CB±1,20D’NoneObservedNoneAnticipatedModerateFlowl-JSoutherlyPipeFlow12”LCPEPipetoaType7CB±1,23D’NoneObservedNoneAnticipatedModerateFlowJ-KSoutherlyPipeFlow12”LCPEPipetoaType2CB±1320’NoneObservedNoneAnticipatedModerateFlowK-LWesterlyPipeFlow18”LCPEPipetoaType2CB±1,365’NoneObservedNoneAnticipatedModerateFlow©2015D.R.STRONGconsultingEngineersInc.LevelTWODownstreamAnalysisPage20VuecrestEstatescityofRenton L-MWesterlyPipeFlow36”LCPEPipetoaditch±1,405NoneObservedNoneAnticipatedModerateFlowNDA2SymbolDrainageDrainageComponentSlopeDistanceExistingPotentialObservationsoffleldinspectorComponentType,DescriptionFromsiteProblemsProblemsresourcereviewer,orresidentName,andSizeDischargeType:sheetflow,swale,drainagebasin,vegetation,Constrictions,undercapacity,ponding,tributaryarea,likelihoodofproblem,SeemapStream,channel,pipe,cover,%114mil,320ftovertopping,flooding,habitatororganismoverflowpathways,potentiatimpacts.Pond;Size:diameterdepth.typeofsensitivearea,destruction,scouring,banksloughing,Surfaceareavolumesedimentation,incision,othererosionAlNaturalDischargePointSheetFlowacrossWestern±0’NoneObservedNoneAnticipatedpropertytineAl-BiWesterlyPipeFlowcampenSpringsConveyance±675’NoneObservedNoneAnticipatedTrickleFlowSystemBi-CiSouthwesterlyWetlandWetlandMitigationArea±950’NoneObservedNoneAnticipatedTrickleFlowatOutletFlowCi-DiSoutherlyPipeFlow12’PipeDischargefromWetland±1025’NoneObservedNoneAnticipatedModerateFlow,Water1’DeepAreaD1-FSoutherlyPipeFlow12”PipesandCatchBasins±1250’NoneObservedNoneAnticipatedModerateFlowwithinTalbotRoadSouthFConvergencePointNDA2convergeswithNDA1at±1250’NoneObservedNoneAnticipatedModerateFlowcatchbasinwestofBorgataApartmentProperty©2015D.R.STRONGConsultingEngineersInc.Page21LevelTWODownstreamAnalysisVuecrestEstatesCityClRenton TASK5MITIGATIONOFEXISTINGORPOTENTIALPROBLEMSAreviewoftheKingCountyWaterandLandResourcesDivision—DrainageServicesSectionDocumentedDrainageComplaintswithinonemileofthedownstreamflowpathsrevealednocomplaintswithinthedownstreampathoftheSite.TheprojectshouldnotcreateanyproblemsasspecifiedinSection1.2.2.1oftheManualandthereforeisnotrequiredtoprovideDrainageProblemImpactMitigationsubjecttotherequirementsofSection1.2.2.2.ProjectrunofffromtheTDAwillbecollectedandreleasedpertheManual’srequirementstoaccommodateLevel3FloodProblemFlowControlandBasicWaterQualityrequirements.Duringconstruction,standardsedimentanderosioncontrolmethodswillbeutilized.Thiswillincludetheuseofastabilizedconstructionentrance,perimetersiltfencing,andothernecessarymeasurestominimizesoilerosionduringconstruction.©2015D.R.STRONGconsultingEngineersInc.Page22LevelTWODownstreamAnalysisvuecrestcityofRenton APPENDIXA.BASINRECONNAISSANCEPROGRAM©2015D.R.STRONGConsultingEngineersInc.Page23LevelTWODownstreamAnalysisVuecrestCityofRenton RECONNAISSANCEREPORTNO.14BLACKRIVERBASINJUNE1987NaturalResourcesandParksDivisionandSurfaceWaterManagementDivisionKingCounty,WashingtonP:BRTOC/m]in KingCountyExecutiveTimHillKingCountyCouncilAudreyGruger,DistrictICynthiaSulli’anDistrict2BillReams,District3LoisNorth,District4RonSims,District5BruceLaing,District6PaulBarden,District7BobGrieve,DistrictSGal)’Grant,District9DepartmentofPublicWorksDonLaBelle,DirectorSurfaceWaterManagementDivisionJosephJ.Simmier,DivisionManagerJIinKramer.AssistantDivisionManagerDaveClark,Manager,River&WaterResoureeSectionLarryGibbons,Manager,ProlectManagementandDesignSectionContributingStaffDougChin,Sr.EngineerRandallParsons,Sr.EngineerAndyLevesque,S;.EngineerBruceBarker,EngineerAmyStonkus,EngineerRaySteiger,EngineerPeteRingen,EngIneerConsultingStaffDonSpencer,AssociateGeologist,EarthConsultants,Inc.JohnBethel.SoilScientist,EarthConsultants,Inc.•rks,PlanningandResourcesJoeNagel,DirectorNaturalResourcesandParksDivIsionRussCahill,DivisionManagerDillJolly,ActingDivisionManagerDerekPoon.Chief,ResourcesPlanningSectionBillEckel.Manager,BasinPlanningProgramContributingStaffRayHeIler,ProjectManager&TeamLeaderMatthewClark,ProjectManagerRobertR.Fuerstenberg,I3iologist&TeamLeaderMatthew3.&uengo,GeologistLeeBenda,GeologistDerekBooth,GeologistDyanneSheldon,WetlandsBiologistCindyBaker,EarthScientistDiJohnson,PlanningSuJ)pOrt1echnicianRobertRadek,PlanningSupportTechnicianRandalBays,PlanningSupportTechnicianFredBentler,PlaimingSupportTechnicianMarkHudson,PlanningSupportTechnicianSharonClausen,PlanalagSupportTechnicianDavidTruax.PlannlagSupportTechnicianBrianVanderhurg,PlanaingSupportTechaicianCarolynM.Bycrly,TechnicalWriterSusannaIlornig,TechnicalWriterVirgialaNewman,GraphicArtistMarciaMcNultv,‘1vpcsetterMildredMiller,TypesetterJakiReed,TypesetterLetaLira,OfficeTechnicianMartyCox,OfficeTechnicianP:CR TABLEOFCONTENTS1SUMMARY1H.INTRODUCTION1lIEFINDINGSINBLACKRIVERBASIN2A.Overview2B.EffectsofUrbanization4C.SpecificProblems5Iv.RECOMMENDATIONS7A.Expandexistingand/orconstructadditionalRIDfacilities7aPreservewetlandsonplateautoprovidenaturalstorage7C,ProtectsteepvalicywaIlsfromerosionandlandslides7D.Reducesedimentationinstfeamsalongvalleyfloor7E.Enforceprohibitionsagainstdumpingdomestictrash7F.IncreasetheoveralleffectivenessofsurfacewatermanagementSV.MAP9AI>PENDICESAPPENDIXA:EstImatedCostsA4APPENDIXB:CapitalImprovementProjectsRatingList134APPENDIXC:DetailedFindingsandRecommendationsC-iPJ3R.TOC/mlrn SUMMAIYBlackRiverBasin.locatedinsouthKingCounty,isnamedforariverthatceasedtoexistin1917,aftermajoralterationstoriversystemsweremadetobuildtheLakeWashingtonshipcanal.ThereconnaissancewasconduciedalongthestreamsandtributariesstiHremaininginthisbasin.DevelopmentinthebasininandaroundthecitiesofKent,Renton,andTukwilahasproducedextensiveareasofimpervioussurface,whichareexpectedtodoublebythetimethebasinreachesitsUeve]oprnentcapacity.Stormrunofffromimpervioussurfacesisdrainedthroughpipesanddischargesinsomecasesdirectlyintothestreamsystem.FieldinvestigationofproblemsintheBlackRiverBasinrevealedthatvolumesandratesofstormwatcrflowshavecontributedtoseriousaccelerationoferosionofstreambanksandlowerslopesandhaveproduceddowucuttingandlandslidesinsomeplaces.Sedimentationresultingfromtheseprocesseshas,inturn,cloggedexistingconveyancesystems,renderingmanyofthemineffective,anddestroyedfishhabitatforspawning,rearing,andmigrating.Inaddition,thegeneralinefficiencyofthebasindrainagesystemhasincreasedthepotentialforflooding.AnotherproblemcitedwasvisiblypoorwaterqualityresultingfromlargeamountsofdomestictrashplacedInstrearnbedsandfromcommercial/industrialrunoff,particularlyneartheLongacresRacetrackinRenton.RecommendationsforactionintheBlackRiverBasininclude:1)expandingR/Dfacilitiesandpreservingwetlandstoassureadequatestormwaterstorage,2)takingmeasurestoprotectsteepvalleywallsfromerosionandlandsIides3)reducingsedimentationonthevalleyfloorwithsedimenttraps,4)increasingcnforccmcntofregulationsagainstthedumpingoftrashintostreams,and5)increasingtheoveralleffectivencasofsurfacewatermanagementinthebasinthroughdoingmoremaintenanceoffacilities,continuingintergovernmentalagreements,loweringvolumesandratesofreleaseforstormwater,andothermeasures.ILIN1’RODUCHON:HistoryandGoalsoftheProgramIn1985theKingCountyCouncilapprovedfundingforthePlanningDivision(nowcalledtheNaturalResourcesandParksDivision),incoordinationwiththeSurfaceWaterManagementDivision,toconductareconnaissanceof29majordrainagebasinslocatedinKingCounty.Theeffortbeganwithaninitialinvestigationofthreebasins--Evans,Soos,andHylebosCreeks-inordertodetermineexistingandpotentialsurfacewaterproblemsandtorecommendactiontomitigateandpreventtheseproblems.TheseInitialinvestigationsusedavailabledataandnewfieldobservationstoexaminegeology,hydrologyandhabitatconditionsineachbasin.FindingsfromthesethreebasinsledtheKingCountyCounciltoadoptResolution6018inAprili986,callingforreconnaissancetohecompletedontheremaining26basins,TheBasinReconnaissanceProgram,whichwassubsequentlyestablished,isnowanimportantelementofsurfacewatermanagement.Thegoalsoftheprogramaretoprovideusefuldatawithregardto1)criticalproblemsneedingimmediatesolutions,2)basincharacteristicsforuseinthepreparationofdetailedbasinmanagementplans,and3)capitalcostsassociatedwiththeearlyresolutionofdrainageproblems.Thereconnaissancereportsareintendedtoprovideanevaluationofpresentdrainagecon-ditionsintheCountyinordertotransmitinformationtopolicymakerstoaidthemindevelopingmoredetailedregulato;ymeasuresandspecificcapitalimprovementplans.TheyarenotintendedtoascrIbeinanyconclusivemannerthecausesofdrainageorerosionproblems;instead,theyaretolieusedasinitialsurveysfromwhichchoicesforsubsequentdetailedengineeringandotherprofessionalenvironmentalanalysesmaybemade.Duetothelimitedamountoftimeavailableforthefieldworkineachbasin,thereportsmustbeviewedasI>:BR/jrI BlackRiverI3asin(COntifliid)descriptlyeenvironmentalnarrativesratherthanasfinalengineeringconclusions.Recommendationscontainedineachreportprovideadescriptionofpotentialmitigativemeasuresforeachparticularbasin;thesemeasuresmightprovidemaximumenvironmentalprotectionthroughcapitalprojectconstructionordevelopmentapprovalconditions.Theappropriateextentofsuchmeasureswillbedecidedonacase-by-casebasisbyCountyofficialsresponsibleforreviewingapplicationsforpermitapprovalsandforchoosingamongcoin-petingprojectsforpublicconstruction.Nothinginthereportsisintendedtosubstituteforamorethoroughenvironmentalandengineeringanalysispossibleonasite-specificbasisforanyproposal.UI.FINIXNGSINBLACKRIVERBASINThefieldreconnaissanceinBlackRiverBasInwasconductedinFebruary1987byRayHelIe;,i’esourccplanner;RaySteigerandDougChin,engineers;andMatthewJ.Brunengogeologist.Theirfindingsandrecommendationsaiepresentedhere.A.OverviewofBlackRiverBasinGeographicandlandusefeatures.BlackRiverBasinisgenerallyboundedonthenorthbythecitiesofRentonandTukwilaandonthesouthbythecityofKent.ThewesternandeasternboundariesareformedbytheGreenRiverand116thAvenueSE,respectively,InthissouthernKingCountybasin.TheI3lackRiver,whichgivesitsnametothisbasin.actuallyceasedtoexistini917,whentheLakeWashingtonshipcanalwasbuiltandthelevelofLakeWashingtonwaslowered,cuttingoffflowtotheBlackRive;.The28-square-milebasininvestigatedbythisfieldteamincludeswhatremainsofthenetwoikoftribulariesthatformerlyconnectedwiththeBlackRiver.TheBlackRiverBasinissplitnearlyequallyintoaneasternuplandplateauandawesternfloodplainintheLowe;GreenRiverValleyalongStateRoadtSR)167ThefloodplainisalmostwhollycontainedwithinthecitiesofTukwila,Renton,andKent,whereextensivedevelopmentinthelasttwodecadeshaschangedthelandscapefromaruralfarmingareatoacommercialandindustrialone.WhileopenspaceandfarmingstillCxiSthere,theareawillbeinfiHed.priinaiilybyacombinationofcommercial,industrial,andsomemulti-familycomplexes,bytheyear2000.TheKingCountyComprehensivePlanshowsthattheuplandareawillbedevelopedaturbandensities.Thistransitionisalreadyinprogress,withcommercialdevelopmentsemergingalongtheKent-KanglevHighway(SR516),theBensonHighway(SR515),andtheCarrRoad-176thStreetSE-PetrovitskyRoadcorridor.Multi-familylanduseoccursintheuplandsalsoandsurroundscommercialdevelopments.Newsingle-familyunitsa;ebeingbuiltthroughoutmostoftheeasternuplandportionofthebasin.Theamountofimpervioussurfaceisexpectedtonearlydoublebetween1985andthetimethebasinisfullydeveloped.Thiswillrequirestrictcontrolsonsurfacewaterdischargetoassurepreventionoffurtherdegradationofthestreamsystem,whichhasalreadybeguntoexhibitadverseenvironmentalimpactsresultingfromurbanization.Otherfactorsofconcerninthisbasinarethosesensitiveareasoccupiedbywetlands,streams,floodplains,coal-minezones,andlandslidezones.Mostlylocatedintheeasternportionofthebasin,theseareashavealreadybeendamagedbytheeffectsofdevelop-P:BR/jr B]ackRRc1Basin(continued)ment.Detailsofthedamage,alongwithsuggestionsformitigation,arecontainedinlatefsectionofthisreport.Dominantgeologicandgeomorphicfeatums.BlackRiverBasinconsistsofthepartoftheDuwarnishValleyeastoftheGreenRiverandthewesternedgeoftheCovingtondriftplain,aplateauunderlainbyglacialdeposits.Smallcreeks,whichflowacrossitsroIlingsurface,haveerodeddeep,narrowravinesupto1.5milesintotheplateau.Downcuttingismigratingheadwardintheupperreaches,anderosionofbanksandlowerslopescauseslandsildinginthecanyonwalls,mostofwhicharenaturallyunstable.Bothoftheseprocessesareacceleratedbyincreasedflowsattributabletourbanization.Sedimentisdepositedwherethestreamsflowontothevalleyfloor.ThesurfaceoftheCovingtondriftplainisdominantlybasaltill,mantledinplaceswithrecessionaloutwashordepositsofpost-glaciallakes.NeartheedgeoftheplateauareseverallensesofsedimentdepositedadjacenttoaglacierlobeintheDuwarnishValley.Oldersedimentsareexposedintheravinesandbluffs.Inthenorth,unconsolidatedsedimentslapupOnic)thesouthernlimboftheNewcastleanticline;sedimentaryandvolcanicrockscropoutinthebluffsnorthofPantherCreekandformtheRenton,Talbot,andEarlingion1-IlIlsinthenorthernendoftheval]eytowardTukwila.Coalwasminedfromthisareafrom1853untilthe1940s.TheDuwamishValleyispartofatroughcarvedintothedriftplainduringthelastglaciation;itlaterbecameanarmofPugetSound.AcatastrophicmudfloworiginatingonMountRainierapproximately5700yearsagodumpedmassiveamountsofdebrisintothetrough.1hisandotherevents,plusthedepositionofalluvia]sediment,expelledthesaltwater.Throughthenineteenthcentury,thecombinedWhiteandGreenRiversmeanderedthroughthevalley.NearRenton,theCedarRiverflowedintotheBlackwhichdrainedLakeWashingtonandflowedintotheDuwamish.Beginningini906asel.iesofchangeswasmadetotheseriversystems.TheCedarRiverwasdivertedintoLakeWashington,andtheWhiteRiverwasdivertedsouthtothePuyallup.TheBlackRiveritselfceasedtoexist.GeomorphicprocessesintheBlackRiverBasinaremostactiveonthewesternedgeoftheplateau.Lakesandwetlandsformedhereinthepoorlydrainedswales,Whereconditionsofdrainageandpercolationareappropriate,smallstreamsflowbetweenthedrcimlins.erodingdeepravinesintotheunconsolidatedsedimentsintheprocess.O?ertime.theravineshavebeenwidenedbymass-wastingoftheirwalls(aprocessaidedbygroundwater)anderosioi;bytributarycreeks;theirupperendshavemigratedtheirupstreamintotheplateau.SedimentcarriedbythesestreamswasdepositedintheDuwamishtrough;afterthetroughbecameanalluvialvalley,smallfansformedonitsedge.Ilydrologicandhydraulicfeatures.TherearethreedistinctgeographIcfeaturesassociatedwiththehydraulicsofBlackRiverBasin:theplateaueastoftheLowerGreenRiverValley,thesteep(5-35°)erosivehillsides,andtheflatfloodplainofthevalleyfloor.Mill,GarrisonSSpring1rook,andPantherCreeks,aswellasthreesmall,unnamedtnhutanies(0023,00061.3,and000GC),alloriginatefromlocationsontopoftheplateau.PantherCreekoriginatesfroniPantherLakeandthesurroundingwetlands.TheP:BlVjr3 BlackRiverBasintcontinued)remainingtrihutaricsoriginateprimarilyfromsurfacewaterstoredinnaturaldepressionsandwetlandareasalongthetopofthehill.Thesurfacewateriscollectedandroutedgenerallynorthandwestvianaturalswales,openroadsideditches,eulverts,andpipelineswithinstreetrights-of-wayand,finally,downthesteephillsidestothe‘allevfloor.Mil]Creek,locatedatthesouthernmostendoftheBlackRiverBasin,flowsnofthbetweentheGreenRiverandSR167andthencrossesunderthehighwayatvariouslocations.MIII,Springbrook,andGanisonCreekscontinuenorthalongthewestsideofSR167andeventuallycombineasSpringbrookCreekbeforebeingpumpedintotheGreenRiverthroughKingCounty’sBlackRiverpumpstation.Tributaries00068andt)OO6CflownorthindependentlydownthehillsideadjacenttoInterstate405andintoRenton.wheretheyenterthecitysstormdrainsystem.Habitatcharactcrisics.‘i’lwuseofnaturalstreamsforurbanstormwaterconduitshashadadetrimentaleffectonmoststreamsystemsintheBlackRiverBasin.Increasedstormwaterreleaseratesthatarehigherthanstreamscanconveywithoutproblemshaveresultedinextensiveerosion.sedimentation.andlandslIdes.Waterqualityproblemscausedbydomesticgarbageplacedinstreamsandpointdischargesofpollutantsareadditionalfactors.Whatisstrikingaboutthisbasinisthatthesehabitatproblemsexisteverywhere.Whilesomeproblemsareworsethanothers,theirimpactonthefishhabitatofeachstreamexaminedwasprofound.Nofishwereobservedinanystreamsduringtheinvestigation.fo;’tifisreasonitissurprisingthatthefishcounterattheBlackRiverptzmpplantlocatedonMonsierRoad(throughwhichallwaterinthebasinisdischargedintotheGreenRiverrecorded84fishenteringthestreamsystemini986.Whilethisfigureishigherthanthatforfishcountsinthepreviousfiveyea;s,itissignificantlylowerthanhistoricallevelsorthepotentiallevelsthatmightbeachievedifstreamswereinbetterconditionforspawning.Thecurrenthabitatconditionsofferlittlehopeforthefutureofthesesalmonruns.Toreachspawningareasfishmustfirst’passtlnoughanopenflood-controldrainageditchforaminimumoffivemiles.Thisditchhasnovegetationorpoolprotectionforfishtotakerefugeagainstpredatorsorwater-temperatureincreases.Inaddition,waterqualityisvisiblypoor.Theeggsoffishthatdoreachspawningterritoryarelikelytobesmotheredwithsedimentorwashedoutduringheavyrainstorms.Iftheseproblemsassociatedwithdevelopmentworsen,streamsystemswillprobablyheleftbiologicallysterile.Reversingthispatternofdegradationisdependentonrevisingthepoliciesandprioritiesintheplanningandzoningactivities,thedevelop-mentreviewprocessesontheSurfaceWaterManagementprogramsofKingCounty,Renton,Tukwila,andKent.B.EffectsofUrbanizationintheRainTheexistingupperreachesoftheBlackRiverbasinwereonceheavilyvegetated,andnaturaldepressionsretainedmuchofthesurfacewater.Waterwasreleasedslowlythen,andthestream$VstefllScouldconveyflowseasily.Developmenthasbroughtabouttheremovalofthisvegetativecoverandfillingofthenaturaldepressions.Manystreamsarenowbeingpiped.Imperviousj;fareincreasingandwilleventuallyaccountfor50percentofthebasi&ssurfacearea.Ingeneral,surfacewaterisenteringnaturalsystemsatafasterandhigherratethanbeforedevelopmentacceleratedtwodecadesago.4 BlackRiverBasin(continued)Earlierdiscussionspointedouttheseriouseffectsthisisproducingintheformoferosionandsedimenttransporttolowerstreamreaches.AdditIonally,sedimentationdecreasestheefficiencyoftheentirebasindrainagesystembyfillingculvertsandchannels.ThisinturnincreasesthepotentialforfloodIng.ThecityofKentremovesanestimated1,100cubicyardsofsedimentannuallyfromitssedimentfacilityatMillCreekPark.TheWashingtonStateDepartmentofTransportationalsoemploysaregularcleaningscheduletoremovegravelandsedimentfromitsculvertunderSouth212thStreetonTributary0023.SedimentfromSpringhrookCreekhasbeentransporteddownstreamfromtheerosivehillsidetoaprivaletroutfarmwestofTalbotRoadandtendereditinoperative.Similarexamplesoccul.throughoutthebasinalongthebottomofthesteephillsideandeastofStateRoad167.E;•osionisfurtheracceleratedbydrainageoutletsfromdevelopmentsandpublicareas.DischargefromapipeintoGarrisonCreekadjacenttoBensonRoadfreefallsforapproximately10feetbeforescourIngtheravineitenters.SimilarerosionoccursonTributary00068wherewaterisdischargedfrontheFredNelsonJuniorHighSchoolacrossBensonRoadtothetopofaseverelyerodedravine.AnonsitedetentionfacilitydownstreamattheVictoriaHillshousingdevelopmentaccumulateslargeamountsofsediment.Itscapacityisdecreasing,andthefunctionofthefacilityisthreatened.ThedevelopmenttrendsinthisbasinmeanthatlandforregionalRIDfacilitieswillbecomemoredifficulttoobtainatthesametimethaterosionandpotentialforfloodingareincreasing.AdditionalproblemsmayarIseifexistingonsiteRIDsystemsmalfunctionfromimproperdesignorconstructionorfromlackofmaintenance.Anonsitefacilityforaprivatelydevelopedtrailerpark,locatedwestoftheBensonRoadadjacenttoGarrisonCreek,exemplifiesthepotentialhazard.UnstablefillwasplacedonthesteepravineandanRIDpondbuiltonitsedge.Thefillbecomessaturatedwhenthepondisinuse,andtensioncracksinthefillalongtheslopeindicatepotentialfailure.Suchaneventwouldaddlargeamountsofsedimenttothedrainagesystem.Developmentmaycreatesimilarproblemselsewhereiftheproperdesign,construction,inspection,andmaintenanceofRIDfacilitiesisneglected.C.SpecificProblemsIdentifiedBlackRiverBasinexhibitsseriousproblemsthroughoutitssystem,withexceptionsonlyinthesouthforkofSpringbrookCreekandonPantherCreekinsubcatchment10.Themostsignificantproblemsnotedbythefieldteamduringitsinvestigationarelistedbelow.:1.Streamchannelerosionacceleratedbythemutingofrunofffromdevelopedareasintostreams.Majorproblemsexistintheravines,wherestreamsarecuttingintotillattheupperendsofcanyonsandassociatedlandslidingandsurfaceerosionoccur(seesection3below).Althoughtheseprocesseshavebeentakingplacenaturallyforalongtime,increasedrunofffromdevelopingareasontheplateauiscausingaccelerationoftheerosion.a.TheworstcasesoferosionobservedincludethoseonMillCreek(0005),P:BR/jr5 BlackRiverBasin(contirnied)GarrisonCreek(0022)anditstributaries(0023,0024,and0025),thenorthforkofSpringbrookCreek(0021),andPantherCreek(0006).l,Prominentexamplesofgullyingatdrainage-structureoutfallsareinMillCreek(0005),SpringbrookCreek(0021),PantherCreek(0006),andbelowBensonRoadonbothGarrisonCreek(0022)andTalho;Creek(00068)C.ExamplesofaccelerateddowneuttingresultingfromincreasedrunofffromdevelopingareasarelocatedinTalbotCreekandtwosmallstreams(0064Aand0006C)inRenton.2.L.andslidingassociatedwithstreamerosioninravines,asaresultofsteepslopesandsaturatedsoils.Instabilitygenerallytakestheformofrotationalfailuresordebrisslidestriggeredbystreamundercutting.Inmanycases,naturalinstabilityisexacerbatedbyfillingand/orbyconstructiononcanyonwalls;forexample,anewfillaboveGarrisonCreekatBensonRoadisfailing,andoldfillsarebeingunder-Cut.Alloftheravinesshouldbeconsideredlandslide-hazardareas.ThesameistrueofthebluffsatthewesternedgeoftheplateauSeventhoughtherehavenotbeenmanyproblemsyet.Thesearemoderatetosteep,landslide-susceptiblesb-pes,espeeiaJlyinthenorthern(Renton)andsouthern(Kent)endsofthebasin--theareaunderthemostdevelopmentpressure.3.Damageto(ordestructionof)habitatdueto:a.Highflowsandhighvelocities,whichremovemacrophylesandbenthicorganisms,plants,insects,andpossiblyfish.VisibleevidenceofhighvelocitieswasnotedonallthestreamsinthisbasinexceptthesouthforkofSpringhrookCreek.b.Sedimentationfromcxcessiveerosion,whichisfillingpoo]s,chokingspawninggravels.andinsomecasesfillingstreambedstothepointofmakingchannelsimpassibletofish.AllofthefourbigstreamsystemsinBlackRiverBasinexhibitthisproblem.TheKentparksdepartmentannuallyremoves1,100cubicyardsofmaterialfromMillCreek.AlargesedimentflowhasfilledtheSpringhrookCreekstreamchanneltoadepthofapproximately5feet,andPantherCreekjustnorthofValleyGeneralHospitalhasalargealluvialfan.CoVisiblypoorwaterquality:1)I..argeamountsofdomestictrashhavebeendepositedinthesestreamcanyons.MillCreekhasbecomeadumpforappliancesatrivermile9.60,andGarrisonCreekappearstohemoreofalandfillthanacreekat1.30.Suchpracticeshaveadetrimentaleffectonwaterqualityaswellasthe?ist1alqualityoftheenvironment.2)Commercialandindustriafenterprisesareproducingrunoffthatcausesmanystreamstobeoily,turbid,andsudsy.SpringbrookCreek(Trib.0005atP.M1.30),flowingunderthebridgeofSouthwest16thStreetjusteastofLongacresinRenton,isoneoftheworstexamplesnoted.TheWesternProcessingfacilityjustupstreamhasbeenidentifiedasasourceoftoxicwastesenteringbothsurfaceandgroundwatersystems.P:BR/jr6 BlackRiverBasin(continued)Iv.RECOMMENDATIONSFORAGIIONHabitat,erosion,landslidIng,andfloodingproblemsintheBlackRiverBasincanbeaddressedbythemeasuresidentifiedbelow.Mostofthesolutionslistedherewillmitigatespecificproblemsobservedduringfieldinvestigationorwillpreventsimilarproblemsiithefuture.However,additionalrecommendationshavebeenincludedtosuggestadministrativeorregulatorymeasuresthatwouldincreasetheoveralleffectivenessofsurfacewatermanagementinthisbasin.A.Expandexistingand/orconstructaddItionalrcgionalk/I)facilitiesontheplateauinordertocontrolstormflowsthatoriginatethere.Sitefacilitiesupstreamofthefourlargecreekravinesthatareexperiencingtheworstdamage.facilitiesshouldberegionalinscopeandshouldfollowthegeneralspecificationsoutlinedinAppendixAofthisreport.ThesewIllimpedethedirectconveyanceofrunoffintothesteep,naturallyerosiveravines,therebyreducingerosionratesthatresultinsedImenttransportandslopeinstabilityandthatdamagehabitat.B.Preservewetlandsontheplateautoprovidenaturalstorage.inaddition,reconsiderPantherLakeforuseasaregionalRIDsite.Althoughthelakehasbeenclassifiedasa#1-Cwetland,theamountofstorageitoffersissubstantialwIthamoderateaUdi-tional(.25-to.50-foot)fluctuationindepth.C.Protectsteepvalleywallsfromerosionandlandslidescausedfromdirectdischargesofstormwater:1.Tightlinedischargesorprovideotherappropriatenonemsiveconveyanceoversteepbillsidcsprovideenergydissipationattheoutfalts.ThishasalreadybeendoneatseveralpointsonMillCreek(Tributary0005)withgoodresults.2.Considerreroutingflowincaseswheretightliningorothcrmethodsarenotfeasible.Forexample,runofffromtheareasoutheastofSpringbrookCreekmighthepipeddownSoutheast200thStreetratherthanroutedintothenorthfork(0021)asitisnow.3.LowerthepotentialforlandslidesbyrestrictingdevelopmcntinandalongthetopsofravinesInparticular,stronglydiscouragefillingalongtheedges;thefillatBensonRoadaboveGarrisonCreek(0022)willprobablyhavetoberemoved.1).ReducesedimentationinstreamsatongthevalleyfloorincaseswheresedimentationisnotadecjuatelypreventedbyRIDandotherupstreammeasures.Inextremecases(probablyincludingPantherCreek[0006]),constructsedimenttraps(withconvenientaccessforremovalofaccumulatedmaterial)atpointstvherestreamsflowontothevalleyfloor.B.hcreaseenforcementofregulatIonsagainstthedumpingofdomestictrashinto;vinesandstreamchannels.TheSeattle-KingCountyHealthDepartmentandtheKingCountyofficeofBuildingandLandDevelopmentshouldheaskedtoinvestigatethiongoingproblemandtotakeappropriateactionwhenviolatorsareidentified.P:BRfjr7 BlackRiverI3asin(coniinued)F.IncreasetheoveralleffectivenessofsurfacewatermanagementintheBlackRiverBasin:1ContinuecoopcmtiveintcrgovemmentaarrangementsbetweenthecitiesofTukwila,Kent,andRenton;theWashingtonStateDepartmentofTransportation;andtheKingCountySurfaceWaterManagementDivisiontoidentifyandproposesolutionstohabitatandhydraulicproblemsinthebasin.Theseeffortsshouldincludedevelopingcost-sharingagreementswherecapitalimprovementsarerequired.2.Evaluateandreduce,ifappropriate,thevolumesandratesofreleaseforstormwateroriginatingfromdevelopments.Presentreleaseratesandvolumesarecausingerosion,sedimentationandhabitatproblems.3.IncreasethemaintenanceandinspectionofexistingKingCountyandcitydrainagesystemstoensurethattheyarefunctioningproperly.4.Encouragepublicparticipationinmaintainingwaterqualityandinstormwatermanagementinthebasin,includingcitizenactionprojectstocleantrashfromstreamsandeducationaboutCitizCflS;oleinmaintainingcleanwaterandstreamsystems.5.Performmoredetailedandcomprehensivehydrologic/hydraulicanalysisofalldrainagesystemswithinthebasintodeterminehowtheexistingfacilitieswillfunctionunderexistingandfutureflows.6.Prepareacomprehensivebasinplanwithparticipationbyallagenciesconcernedwithsurfacewatermanagementinthebasin.Theplanshouldassesstheeconomie,hydrologic,andhabitatimpactofindividualprojectsonabasin-widescale.P:13R/jr8 \:iI:‘I-\,..\:flMu1fl’s\I::L,-\N•;!‘N—11-:..:.‘,,\1:I‘.//\\j\j’AwBLACKRIVERBASINBasinBoundary.—\SubcatchrnentBoundaryCollectionPoint0006•0301StreamtTributaryNumberProposedProject4\h1.’\ APPENDIXBCAPITALIMPROVEMENTPROJECTRANKINGBLACKRIVERBASINPriortotheBlackRiverBasinfieldreconnaissance,sevenprojectshadbeenidentIfiedandrafedusingtheCIPselectioncriteriadevelopedbytheSurfaceWaterManagement(SWM)andNaturalResourcesandParksDivisions.followingthereconnaissance,sevenprojectsremainproposedforthisarea.Theyincludeonenew,previouslyunidentifiedandunratedproject.Thisdisplacesonepreviouslyselectedproject,whichwaseliminatedbasedontheconsensusofthereconnaissanceteambecausenoproblemwasapparentinthefield.ThepreviousSWMcapitalimprovementprojectlistfortheBlackRiverBasinhadanestimatedcostof$1,250,000,whitetherevisedlistincreasestoanestimatedcostof$1,280,000.This2.4percentincreaseinestimatedcapitalcostsisduemainlytoupwardrevisedcostfiguresforsecuringoracquiringeasementsoverwetlandsandcostsassociatedwithanewprojecttosolveapreviouslyunidentifiedproblem.ThefollowingtablesummarizesthescoresandcostsfortheCIPsproposedfortheBlackRiverBasin.TheseprojectswereratedaccordingtopreviouslyestablishedSWMProgramCitizenAdvisoryCommitteecriteria.Theprojectsrankedbelowarethoseforwhichthefirstratingquestion,ELEMENT1:GO/NOGO,”couldbeansweredaffirmatively.TheseprojectscanheconsIderednowformergingintothe‘lIve1’CIPlist.RANKPROJECTNO.SCORECOSTIO3O2125$208,0002030V110125,0003030910026,00040301*95345,00050305*90116,00060307*60309,00070304*55151,0QOTOTALS1.280,000*IndicatesprojectwasidentifiedbytheSurfaceWaterManagementDivisionpriortoreconnaissance.P:BR.APB.B-I Tiil,.&Collect. !I!n RIVCf Mite Point ExistIng c?I%2!Y ?rop Proj Conditions and Problems Anticipated Conditions and Problems .Recommendations 25 0006C 5 IIabitat Rolling Hills Creek exhib its oil sheen on water in upper portion of the creek. Little or no fish habitat (or potential)exists. Little change due to riprap along stream to protect sewer line that parallels stream. None. 26 0009 RM .00- .15 9 Geology Dank and tower-slope erosion in small tributary channel, especially behind eonstnic tion equipment lot. flows in tributary will in- crease;erosion will continue causing sedimentation down- stream and perhaps threaten stability of building. -RID in upper basin. -Remove fill along stream. 27 0009 RM .15-.20 9 1 labitat Lots of litter;stream has extensive downcutting,bank erosion,and bedload movement. Worsening of water quality, sedimentation,and erosIon. -Reduce the volume and rate of water to non-erosive levels by new RID. -Consider restricting future develop- ment (down-zone). -Community action projects could remove litter. 28 0020 RM .20 12 Habitat Sediment has destroyed fish habitat.City of Kent removes sediment each year. Possible flooding and sedi mentation along S 192nd St. Remove sedimentation source (see also Trib.0023,RM.95). 29 0020 RM .50- .70 21 Geology Bank erosion,Iandsliding in canyon due to outfalls at end of SE 196th St.and from R/D on 200th plus natural sensitivity (landslides).Heavy damage in Jan.86 storm.SeW- mentation above old road, and in trout farm below Talbot Rd.,as well as cr0- sion in the ravine. Problems will continue.-Control storm flows.Increase R/D above RM .40 in 0021;reroute or control flows from vicinity of SE 200th (tightllne west on 200th). -Provide energy dissipation at RID outfall (RM .40). -Restrict development on north side of 0021 (runoff to be tightlineU or routed around ravine). P:BR.APC/mlm C-7 Ti•ib Sr Collect Item River Mile Point Cçgorv Existing Propjroj.Conditions and Problems Anticipated Conditions and Problems Rccqiimciations 30 0020 RM .60 21 Habitat Excess sediment from upstream has destroyed a private trout farm. Thousands of fish were killed during Jan.86 storm. Further sedimentation from upstream sediment sources. Several options:construct sediment pond above Talbot Road.Reduce flow rates and volumes in Trib. 0021.Increase RID upstream of Talbot Rd.Down-zone land to reduce surface water impacts of future development. 31 0021 RM .00 0.50 32 0021 RM .40 22,Geology 22 1-lydrology 0302 Bank erosion,landsliding in ravine due to outfalls at end of SE 196th St. and from RID pond at SE 200th plus natural sensitivity (landslides). Heavy damage in Jan.‘86 storm.Sedimentation above old road and in trout farm below Talbot Rd.(0020),as well as erosion in the canyon. The upper reaches of Springbrook Creek lie within the city of Renton City Watershed.The creek originates in highly cr0- sive and steeply sloping soils.Alterations of the natural drainage patterns by development,roadway construction,and poor practice in handling runoff have increased ero sion and sediment transport to the lower gradient downstream reaches. Problems will continue. Development will continue and impervious area will continue to grow.Increased runoff will further erode the unstable soils carrying sediment and debris downstream,where they will reduce the efficiency of or even destroy culverts,pipe- lines,and streambeds. Flooding could result from the inefficient facilities coupled with the greater runoff. -Control storm flows:RID above RM .40 in 0021;reroute or control flows from vicinity of SE 200th (tightline flows west on 200th). -Provide energy dissipation at RID outfall (RM .40). -Restrict development on north side of 0021 (runoff to be tightlined or routed around canyon). -Construct a regional RID faci lity in the natural drainage swale at the upper reaches of this system. -Construct a dam across the swale with an outlet control structure and an overflow spifiway. -Tightlinc existing drainage into area to further reduce erosion and raise existing roadway to prevent flooding. P:UR.APC/mlm C-S APPENDIXB.DOWNSTREAMSYSTEMBACKWATERANALYSIS©2015D.R.STRONGConsultingEngineersInc.Page24LevelTWODownstreamAnalysisVuecrestCityofRenton ATTEI’JUATB3FLOWANALYSISConveyanceSystemVariables:d=pipedianatern=Manning’sNuner1=lengthofpipeRpeStructuresSubasinsAAACtDCTcTributaries99888777666555444333222111H\LE1Ct9TOINLEfI900.000.906.30.82800.000.906.30.82700.000.906.30.82600.000.906.30.82500.000.906.30.82400.000.906.30.82300.000.906.30.82200.000.906.30.82I00.000.906.30.82Assunptiens:100year1WBevationof185.5inCanpenVaultRowof4.00cfs(3.5cfsfromCanpen+0.5fromVC)Thisflowisassumedthroughtheentirerun,fromtheupstreamendtothevaultinletISlopeivertinvertover-QVBendtDBinoutflowFullFullelev.FlewRowft%ftftftcfsfP5©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage25CityofRentonFROfTocBcBiRHQRSQR0-dterialnsubasinRatioSfAcMn.cfscfsin3.278.008.000.0012P’C0.01159.22.01236.12234.93244.005.997.62043.270.008.000.0012PJC0.01191.512.00234.93223.95239.9314.6318.623523.270.008.000.0012R’C0.01154.813.01223.67216.54228.67152319.395023.270.008.000.0012PJC0.01147.12.29211.28210.2220.546.398.141543.270.008.000.0012Ps/C0.01140.112.02208.20203.38213.2014.6418.64023.270.008.000.0012PVC0.01146.412.00202.38196.81207.3814.6318.622023.270.008.000.0012PVC0.01185.32.00191.46189.75203.125.987.61543.270.008.000.0012Ps/C0.01144.312.01189.75184.43197.6214.6318.63043.270.008.000.0012L0.0124.25.00181.21181195.078.6511.02904Vuecrest ©2015D.R.STRONGConsultingEngineersInc.Page26LevelTWODownstreamAnalysisCityofRentonBACKWATERCOMPUTERPROGRAMFORPIPESPipedatafromf±le:CP#9TOINLET1.bwpSurcharqeconditionatintermediatejunctionsTailwaterElevation:185.5feetDischargeRanqe:O.25to10.Stepof0.25[cfs]OverflowElevation:244.feetWeir:NONEUpstreamVelocity:O.feet/secPIPENO.1:4LE—12”CP@5.OOtOUTLET:181.00INLET:181.21INTYP:5JUNCNO.1:OVERFLOW-EL:195.07BEND:90DECDIA/WIDTH:4.0Q-RATIO:0.000(CE’S)HW(PT)HWELEV.N-FACDCDNTWDODEHWOHEI*******************************************************************************0.254.30185.51*0.0120.210.124.504.504.304.300.250.504.30185.51*0.0120.300.174.504.504.294.300.380.754.32185.53*0.0120.370.204.504.504.294.320.481.004.34185.55*0.0120.430.234.504.504.294.340.581.254.37185.58*0.0120.480.264.504.504.294.370.671.504.40185.61*0.0120.520.294.504.504.304.400.751.754.44185.65*0.0120.570.314.504.504.304.440.842.004.48185.69*0.0120.610.334.504.504.304.480.932.254.54185.750.0120.650.354.504.504.304.541.022.504.59185.20*0.0120.680.374.504.504.314.591.112.754.66185.87*0.0120.720.394.504.504.314.661.203.004.73185.94*0.0120.750.414.504.504.324.731.293.254.80186.01*0.0120.780.434.504.504.324.801.413.504.89186.10*0.0120.800.454.504.504.324.891.533.754.97186.18*0.0120.830.474.504.504.334.971.674.005.07186.28*0.0120.850.484.504.504.345.071.81PIPENO.2:44LE—12”CP812.01%OUTLET:184.43INLET:189.75INTYP:5JUNCNO.2:OVERFLOW-EL:197.62BEND:0DECDIA/WIDTH:4.0Q-RATIO:0.00Q(CFS)HW(FT)HWELEV.N-FAGDCDNTWDODEHWOHWI*******************************************************************************0.250.22189.97*0.0120.210.101.081.080.21*****0.220.500.34190.09*0.0120.300.141.081.080.300.340.750.43190.18*0.0120.370.171.101.100.37*****Q431.000.51190.26*00120.430.191.121.120.43*****0.511.250.58190.33*0.0120.480.211.151.150.48*****Q5$1.500.65190.40*00120.520.231.181.180.52*****0.651.750.71190.460.0120.570.251.221.220.57*****0.712.000.76190.51*0.0120.610.271.261.260.610.762.250.81190.56*0.0120.650.281.321.320.650.812.500.87190.62*0.0120.680.301.371.370.68Q$72.750.91190.660.0120.720.311.441.440.72*****0.913.000.96190.71*0.0120.750.331.511.510.75*****0.963.251.03190.78*0.0120.780.341.581.580.78*****1.033.501.10190.85*0.0120.800.351.671.670.801.103.751.17190.92*0.0120.830.371.751.750.831.174.001.25191.000.0120.850.381.851.850.85*****1.25Vuecrest PIPENO.3:JUNCNO.3:85Lf—12”CP@2.00%OUTLET:189.75INLET:191.46INTYP:5OVERfLOW-EL:203.12BEND:5DEGIDIA/WIDTH:4.0Q-RATIO:0.00Q(CFS)HW(FT)HWELEV.*N-FACDCDNTWDODEHWOHWIQ(CfS)HW(FT)HWELEV.*N-FACDCONTWDODERWCHWI******************************************************************************0.250.27191.730.0120.210.150.220.220.21*****0.270.500.39191.85*0.0120.300.210.340.340.300.390.750.48191.94*0.0120.370.260.430.430.37*****Q4$1.000.56192.02*0.0120.430.290.510.510.43*****1.250.63192.09*0.0120.480.330.580.580.48*****0.631.500.70192.16*0.0120.520.360.650.650.52*****Q7Q1.750.76192.22*0.0120.570.390.710.710.570.762.000.81192.27*0.0120.610.420.760.760.61*****0.812.250.27192.33*0.0120.650.450.810.810.65*****0.872.500.92192.380.0120.680.480.870.870.680.922.750.97192.43*0.0120.720.510.910.910.72*****0.973.001.02192.48*0.0120.750.530.960.960.75*****1.023.251.08192.54*0.0120.780.561.031.030.78*****1.083.501.15192.61*0.0120.800.591.101.100.801.153.751.23192.69*0.0120.830.611.171.170.831.234.001.30192.76*0.0120.850.641.251.250.85*****1.30PIPENO.4:46LF—12”CP812.00%OUTLET:196.81INLET:202.38INTYP:5JUNCNO.4:OVERFLOW-EL:207.38BEND:20DEGDIA/WIDTH:2.0Q-RATIO:0.00Q(CFS)**********0.250.500.751.001.251.501.752.002.252.502.753.003.253.503.754.00HW(FT)HWELEV.N-FACDCDNTWDODEHWOHWI*********************************************************************0.22202.60*0.0120.210.100.000.100.21*****0.220.34202.72*0.0120.300.140.000.140.300.340.43202.81*0.0120.370.170.000.170.37*****Q430.51202.890.0120.430.190.000.190.43*****0.510.58202.96*0.0120.480.210.000.210.48*****0.580.65203.03*0.0120.520.230.000.230.52*****0.650.71203.09*0.0120.570.250.000.250.57*****0.710.77203.15*0.0120.610.270.000.270.61*****Q•770.83203.21*0.0120.650.280.000.280.65*****0.830.88203.26*0.0120.680.300.000.300.68*****0.880.93203.31*0.0120.720.310.000.310.72*****0.930.99203.37*0.0120.750.330.000.330.75*****Q991.05203.43*0.0120.780.340.000.340.78*****1.051.13203.51*0.0120.800.350.000.350.80*****1.131.20203.58*0.0120.830.370.000.370.83*****1.201.28203.66*0.0120.850.380.000.380.85*****1.28PIPENO.5:40LF—12”CP812.02%OUTLET:203.38INLET:208.20INTYP:5JUNCNO.5:OVERFLOW-EL:213.20BEND:0DEGDIA/WIDTH:2.0Q-RATIO:0.00*******************************************************************************0.250.22208.42*0.0120.210.100.000.100.21*****0.220.500.34208.54*0.0120.300.140.000.140.300.340.750.43208.630.0120.370.170.000.170.37*****0.431.000.51208.71*0.0120.430.190.000.190.43*****0.511.250.58208.78*0.0120.480.210.000.210.48*****0.581.500.65208.85*0.0120.520.230.000.230.52*****0.651.750.71208.91*0.0120.570.250.000.250.57*****0.712.000.76208.96*0.0120.610.270.000.270.61*****0.762.250.81209.01*0.0120.650.280.000.280.65*****0.812.500.87209.07*0.0120.680.300.000.300.680.872.750.91209.11*0.0120.720.310.000.310.72*****0.913.000.96209.16*0.0120.750.330.000.330.75*****0.96©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage27CityofRentonVuecrest oc:C’%J00)G)0>0ccr-inifl(:D(r-Ccc‘occDc’r-r-cncLOrcjincD—icflcc’jOrQ—c)aorc)(NC’JLI)0-(NC)(N0QC’GH-H<N0H‘(NCflT’LOLO-r—coODOOGC—I—1(NCflDF-(NC)LI)LI)D1ODODO’0CJ(flD3(\]C)LI)LO0.....-(....(H-H-HH(14Q-DcccDccccccc——i—1cXQccc.cacc0c—i—i—i—C—i-c-ccccccc><>-l•>-iH•’(H’(E—••oo•zo(((<HH1----K3--HF-4--K----4Hjf—i--4-14((1<E-O-<------E01((14(-(4(3((4(EHQ144((--)<---(-((F:11<1(44c-Icc----)j(coi:<--(4--((((r-I(4C(C--((C-)CcnhX-(<(NI-<‘1---)cQI--K-(<((4(--CI--.o•0-H-c-fl1(:VcocC)L)HHDflCOCNr—HLflcoCNU)cODCflLI)(NHcD-C)O@J-—4LI)OD(NLI)coQ()LI)Cfl1cLDrC)cO(\Jr[—ODDODC0C’)()ci‘ru)nLO.DD——[‘—COcocoe-c-jcnc-rLI)LI)D.D--[—xODc-0-c-jc)C)LflLI).....):-..Q-.•-cDccc•.TDcDccDcDDcDccQ0cccDcc•.()QQQ)QQQQ..\JQH-H-E--I-3..--KrILI)I-10-KLI)QLI)GD(NLI).OHI-DCHc3QØ—)DC)O0)—4CDODO-(NC)LI)LQDf)YLi)I)CflInCflE-0-HI)-)1%)(NCfl(fl)flrrr:rflLI)U)LI)DE-0-K—i—11%)C%JC’-)C’-)(N(NI)c’)P)(0C)(flE—10-KHH—(NC)I)r...)Hi))•—i)•—fCDQcDcDFCQQQ0QLi))D0)D00DQF100QQ0D0000D0cD000HC)0C)CDC)C)C)rC4C)—-K•cr-U)-..cLI)CflC)C)(NI)-KC)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)LI)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)0)<-KC)LI)LI)0LI)C)HI)l(N•FC)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)—1C)C)C)0C)C)C)C)C)C)C)C)C)C)C)C)•HIC)C)V—i(NI)3••••C))::)c--•...........•.‘‘L0DE-L................cnC)C)C)C)-KC)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)-1C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)CN-KC)C)C)C)C)C)C)C—)I-)4(N-K-K-K-crLI)I—C)••-KLI)C)U)C)I))LI)coHSrLI)0)r-OC)H••-KC)(flDC))—I))WCOI))—(N(flLI)D1-••C)1-0)—11)U)I)I)cflO)H(DZ-K—1(N(NI)iI)I)fl‘I‘U)HHHH(NC’J(N(N(N(NI)I)c)C)I)I))E-(DZ-KH—LH(N(NC’-)••••bFi)•........••...•.••••••.•••‘••••‘••‘••••C)C)C)C)1)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)L:lC)C)C)C)C)C)C)H-KHH4U)-KC))U)(0C)enU)0H-HC)1-I)C)I)-)1-HU)C)I))U)C)C)flU)0U)—LC)r-)CO(N[-—)U)C)(NU)C)C)I))U)0c—iC)—I)CX)I)J1-I—C)C)C)UI))flI)zr‘rU)U)DLQLQ[——-C)CQC)(JC\JI’)C)crciU)U)-DLOLOr-r—[-(0)0)UI)Jf)IflVrU)U)•••••.••••••••••••••••••Q‘•••‘••••••••••..•-KC)C)C)C)_)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)o\°IC)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)o\°)-KC)C)C)C)C)C)C)Z-KC)ZCN-KC)xC)reicicic-i•cUc-II)iei(NC-iC’iI))CJ(NI))(NIi(N(NI)C\J•U(NC\J(N(N(N(N(NC’)(NI))(N(NI)J(NC\JC\J•flUK(N(N(N(NI)J(N(NHH—H0)I)-KHH—H—1C—iHH-1H—1HHI)I)-K—1-1H—iH-H—1C—I—L-1—H—i—1—(NK1—1—LHH—CC)C)C)I--LC)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)—1C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)—ix-1C)C)C)C)C)C)C).•.,c:r•...............I—I-K•...............Cr)14•......C)C)C)C)))LiU)ZC)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)cDZ-C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)C)jI))-KC)C)C)C)C)C)C)C•-K••IC1<1<IC1<C)-K-KII-K-K-K-K-K-K-K-KC)-K-K-KICICKI-K-K-K-K0CIC-K-K-K-KIC(NI(NICC)ICCCCI•-K(N(N•-K(N(N•-KI)C)r-U)()>-KU)I-QcrHCOIC)U)C)U)-HC)I(NC)U>COC)C)JLDC)I)-C)L-D(NHC)0)C)U>-KU)-DU)(N0)U)IIC)I)2•.(NU)‘-C1-C)0)0)C)HH(N(N(flI)U)Li):•.(-KC)C)—I-I(NCflziU)LQLO—0)C)C)C):•.-KH(NI)siU)U)D•••.(N-••••••••••••••••(N•••••••‘••••••••••‘••••I))U)CLC)C-HC1-KHHC-IC—iCHV—I(N(N(N(N(N(N(N(N(N(N-HN(Nrrrr)C)C)C:)rTC•C3C)C4CrU)Hz1U)U)U)U)U)U)U)C)C)C)C)HC-IC-I—1C-I-I—IV—IH-H-IH—1—1HC—II(N(N(N(N(N(N(N(N(N(N(N(N(N(N(N(NI-K(NCC)(N(C)(Y)Y)(N)<N(N(N(N)-K(N(N(N(N(N(N(N(N(N(N(N(N(N(N(N(NI::(N(N(N(N(N(N(N(N(N(NI(N(N(N(N(N(N(N00XI00XICII14C-C4CICEiIK-L4-K-K10<t—(C——If-r;1OS(C)C)(-U)ç)C>Ht-U)C)LU(NC)C0(N1-(NI-(-C)C))()•Cr(NU)>—1(C)(N(N0-(—(0C)I—(C)I)))()Lr(C)(N(Na>(Nco(No-o(N(•)wC)HV—IC-ICEUK(N(C)C)U)Or-r-O)COI))0)C)C—)H(NI)C(NI))U)U)-0r-CoC)0)0)C)—1(NC)srQ(N(flUU)U)LQf-z••••—-K••‘•‘•••••••.••••.••••••••••I••••••.C-H-H-HC-IIC)C)C)C)C)C)C)C)C)C)C)—1HHC—I—IC)C)C)C)C)C)C)C)C)C)C)—1-IH-IHICC)C)C)C)C)C)C)‘••.•“•••.•.IcCLi)-KNC-aODIc-K-KIC••-K.•IC•.IcLI)C)LI)C)00—-KU)C)U)C)U)C)U)C)U)C)U)C)U)C)U)C)Q0-KU)C)U)C)U)C)U)C)U)C)U)C)U)C)U)C)0C)—-KU)C)U)C)U)C)U)0C’-]U)(-C)ZZU)-K(NU-)r-C)(NU)I-C)(NLI)[—C)(NU)I—C)ZZU)-K(NU)1—C)(NU)r—C)(NU)I-C)(NU)I-C)Z(I)IC(NU)I-C)(NU)I-•••••••••.•.••.••••.••••••••t4cf-flInO)L]U-KC)C)C)C—IHHH(N(N(N(N(NI)(flI)3C(J(JC)C)C)-IHH—1(N(N(N(N(NC)(NI)zrçxUUC)C)C)C—I-IC—f—)CCZ—‘zQZICCa)F-lUHh-ILYC4D-KhDQ)IC 2.000.79235.72*0.0120.510.270.520.520.610.792.250.85235.780.0120.650.290.590.590.650.852.500.90235.83*0.0120.680.300.650.650.680.902.750.96235.$9*0.0120.720.310.710.710.720.963.001.02235.950.0120.750.330.7$0.7$0.751.023.251.10236.03*0.0120.780.340.$60.860.781.103.501.17236.10*0.0120.800.350.950.950.801.173.751.26236.19*0.0120.830.371.041.040.831.264.001.35236.2$*0.0120.850.381.141.140.85*****1.35PIPENO.9:59LF—12’CP92.01%OUTLET:234.93INLET:236.12INTYP:5Q(CFS)HW(FT)RWELEV.N-FACDCDNTWDODEHWOHWI*******************************************************************************0.250.27236.39*0.0120.210.150.220.220.210.270.500.39236.51*0.0120.300.210.340.340.300.390.750.49236.61*0.0120.370.260.430.430.37*****Q491.000.58236.70*0.0120.430.290.520.520.43*****Q•5$1.250.67236.79*0.0120.480.330.590.590.480.671.500.75236.87*0.0120.520.360.660.660.52*****Q751.750.83236.95*0.0120.570.390.720.720.570.832.000.91237.03*0.0120.610.420.790.790.61*****0.912.250.99237.110.0120.650.450.850.850.65*****Q992.501.07237.190.0120.680.480.900.900.681.072.751.15237.27*0.0120.720.510.960.960.72*****1.153.001.24237.36*0.0120.750.531.021.020.75*****1.243.251.34237.46*0.0120.780.561.101.100.781.343.501.45237.57*00120.800.591.171.170.801.453.751.57237.69*0.0120.830.611.261.260.831.574.001.69237.81*0.0120.850.641.351.350.85*****1.69R:\2012\1\12102\3\Documents\Reports\FinaRLevel2DS12102.docx©2015D.R.STRONGConsultingEngineersInc.LevelTWODownstreamAnalysisPage29CityofRentonVuecrest APPENDIX“B”CSWPPP©2015D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage63TechnicalInformationReportCityofRenton ConstructionStormwaterGeneralPermitStormwaterPollutionPreventionPlan(SWPPP)forVuecrestEstates&VuecrestIIShortPlatPreparedfor:TheWashingtonStateDepartmentofEcologyNorthwestRegionalOffice319016thAvenueSEBellevue,WA98008-5452PermitteeIOwnerDeveloperOperatorIContractorHarbourHomes,LLCHarbourHomes,LLCTBD1441N.34thStreet,Suite2001441N.34thStreet,Suite200Seattle,WA98103Seattle,WA981034800BlockofSmithersAvenueSinRenton,WashingtonCertifiedErosionandSedimentControlLead(CESCL)NameOrganizationContactPhoneNumberTBDEarthSolutionsNW,LLC425.284.3300SWPPPPreparedByNameOrganizationContactPhoneNumberMaherA.Joudi,PEDRStrongConsulting(425)827-3063Engineers,Inc.SWPPPPreparationDateSeptember23,2015ProjectConstructionDatesActivityIPhaseStartDateEndDateSiteDevelopmentTEDTEDD.R.STRONGConsultingEngineers,Inc.StormwaterPollutionPreventionPlanVuecrestEstates&VuecrestIIShortPlat TableofContentsProjectinformation2I.1ExistingConditions21.2ProposedConstructionActivities22ConstructionStormwaterBestManagementPractices(BMPs)42.1The12Elements42.11ElementI:PreserveVegetationIMarkClearingLimits42.12Element2:EstablishConstructionAccess52.1.3Element3:ControlFlowRates62.1.4Element4:InstallSedimentControls72.1.5Element5:StabilizeSoils92.1.6Element6:ProtectSlopes102.1.7Elementf:ProtectDrainInlets112.1.8Element8:StabilizeChannelsandOutlets122.1.9Element9:ControlPollutants132.1.10Element10:ControlDewatering162.1.11Elementll:MaintainBMPs172.1.12Element12:ManagetheProject183PollutionPreventionTeam204MonitoringandSamplingRequirements214.1SiteInspection214.2StormwaterQualitySampling214.2.1TurbiditySampling224.2.2pHSampling235Dischargesto303(d)orTotalMaximumDailyLoad(TMDL)Waterbodies245.1303(d)ListedWaterbodies245.2TMDLWaterbodies246ReportingandRecordKeeping256.1RecordKeeping256.1.1SiteLogBook256.1.2RecordsRetention256.1.3UpdatingtheSWPPP256.2Reporting256.2.1DischargeMonitoringReports256.2.2NotificationofNoncompliance26D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPagei ListofTablesTableI—SummaryofSitePollutantConstituents2Table3—pH-ModifyingSources15Table5—Management18Table7—TeamInformation20Table8—TurbiditySamplingMethod22Table9—pHSamplingMethod23ListofAppendicesA.SiteMapB.BMPDetailC.CorrespondenceD.SiteInspectionFormE.ConstructionStormwaterGeneralPermit(CSWGP)D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageii ListofAcronymsandAbbreviationsAcronymIAbbreviationExplanation303(d)SectionoftheCleanWaterActpertainingtoImpairedWaterbodiesBFOBellinghamFieldOfficeoftheDepartmentofEcologyBMP(s)BestManagementPractice(s)CESCLCertifiedErosionandSedimentControlLeadCo2CarbonDioxideCR0CentralRegionalOfficeoftheDepartmentofEcologycswGPConstructionStormwaterGeneralPermitCWACleanWaterActDMRDischargeMonitoringReportDODissolvedOxygenEcologyWashingtonStateDepartmentofEcologyEPAUnitedStatesEnvironmentalProtectionAgencyEROEasternRegionalOfficeoftheDepartmentofEcologyERTSEnvironmentalReportTrackingSystemESCErosionandSedimentControlGULDGeneralUseLevelDesignationNPDESNationalPollutantDischargeEliminationSystemNTUNephelometricTurbidityUnitsNWRONorthwestRegionalOfficeoftheDepartmentofEcologypHPowerofHydrogenRCWRevisedCodeofWashingtonsPccSpillPrevention,Control,andCountermeasuresuStandardUnitsSWMMEWStormwaterManagementManualforEasternWashingtonSWMMWWStormwaterManagementManualforWesternWashingtonswPPPStormwaterPollutionPreventionPlanTESCTemporaryErosionandSedimentControlSWROSouthwestRegionalOfficeoftheDepartmentofEcologyTMDLTotalMaximumDailyLoadVFOVancouverFieldOfficeoftheDepartmentofEcologyWACWashingtonAdministrativeCodeWSDOTWashingtonDepartmentofTransportationWWHMWesternWashingtonHydrologyModelD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage1 IProjectInformationProject/SiteName:VuecrestEstates&VuecrestIISPStreet/Location:4800BlockofSmithersAvenueSouthCity:RentonState:WAZipcode:98055Subdivision:N/AReceivingwaterbody:BlackRiver1.1ExistingConditionsTotalacreage(includingsupportactivitiessuchasoft-siteequipmentstagingyards,materialstorageareas,borrowareas).Totalacreage:II.76Disturbedacreage:5.874Existingstructures:0.10Landscapetopography:0.40(estimate)Drainagepatterns:0.02(streamchannel)ExistingVegetation:0.50(treeretention)CriticalAreas(wetlands,streams,higherosionStreamandadjacentwetlandrisk,steepordifficulttostabilizeslopes):5.10Listofknownimpairmentsfor303(d)listedorTotalMaximumDailyLoad(TMDL)forthereceivingwaterbody:NoneknownTableIincludesalistofsuspectedand/orknowncontaminantsassociatedwiththeconstructionactivity.TableI—SummaryofSitePollutantConstituentsConstituent(Pollutant)LocationDepthConcentrationNoknowncontaminantsexistontheSite1.2ProposedConstructionActivitiesTheapplicanthasgainedapprovaltocreate28lots(VC—20lots,VCll—8lots)withlotsizesrangingfromapproximately4,500s.f.to17,046s.f.The28single-familyresidencescombinedwiththeirdrivewayswillcreateapproximately95,800s.f.(3,600sftobefullydispersed)ofimperviousarea.Themajorityoftheproposedrightofwaywillbeimprovedwith26feetofpavement,verticalcurb,gutter,eight-footplanterstripandfive-footsidewalks.Portionsoftherightofwaythroughthesensitiveareaswillbeimprovedwith22feetofpavement,curbandgutterandafive-footsidewalkononesidewhiletheportionfrontingLots1through7ofVCIIwillbeimprovedwith26feetofpavement,curbandgutter,eightfootplanterandfive-footsidewalkononeside(modifiedCityofRentonHalfStreetstandard).Twostubroadsareproposedtoservefourlotseach;theywillbecomprisedof20feetofpavement.Theimprovementsfromright-ofwaysandstubroadswilladdapproximately63,750s.f.ofimpervioussurface.Thetotaldeveloped/disturbedareais259,475s.f.ofwhich159,550isimpervious(155,950totheD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage2 detentionfacilitydueto3,600s.f.offulldispersion).Theremainderofthedisturbedarea(99,925s.f.)willconsistoflandscapingandlawns.TheProjectisrequiredtoprovideBasicWaterQualitytreatmentandLevel3FlowControl,perthe2009KCSWDM(Manual).Allsurfacewaterrunofffromimpervioussurfaceswillbecollectedandconveyedtoastormdetention/waterqualityvaultlocatedinTract“A”ofVC.AppendixAshowstheSitePlanwithT.E.S.C.measures.Finalstabilizationofthedisturbedlandwillinclude:.Asphaltroadway.Concretesidewalks.Formallandscapeplanting.BufferlandscapeplantingContaminatedSiteInformation:Proposedactivitiesregardingcontaminatedsoilsorgroundwater(example:on-sitetreatmentsystem,authorizedsanitarysewerdischarge):Notapplicableasnoknowncontamination.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage3 2ConstructionStormwaterBestManagementPractices(BMPs)TheSWPPPisalivingdocumentreflectingcurrentconditionsandchangesthroughoutthelifeoftheproject.Thesechangesmaybeinformal(i.e.,hand-writtennotesanddeletions).UpdateLtheSWPPPwhentheCESCLhasnotedadeficiencyinBMPsordeviationfromoriginaldesign.2.1The12Elements2.11ElementI:PreserveVegetationIMarkClearingLimitsToprotectadjacentpropertiesandreducetheareaofsoilexposedtoconstruction,thelimitsofconstructionwillbeclearlymarkedbeforeland-disturbingactivitiesbegin.Treesthataretobepreserved,aswellasallsensitiveareasandtheirbuffers,shallbeclearlydelineated,bothinthefieldandontheplans.Ingeneral,naturalvegetationandnativetopsoilshallberetainedinanundisturbedstatetothemaximumextentpossible.TheBMPsrelevanttomarkingtheclearinglimitsthatwillbeappliedforthisprojectinclude:ThesiltfencewillbeplacedaroundtheperimeterofthedevelopableareaoftheSite.BMPwillbeimplementedatthestartofconstruction.AlternateBMPsformarkingclearinglimitsareincludedinAppendixCasaquickreferencetoolfortheonsiteinspectorintheeventtheBMP(s)listedabovearedeemedineffectiveorinappropriateduringconstructiontosatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD).Toavoidpotentialerosionandsedimentcontrolissuesthatmaycauseaviolation(s)oftheNPDESConstructionStormwaterpermit(asprovidedinAppendixD),theCESCLwillpromptlyinitiatetheimplementationofoneormoreofthealternativeBMPslistedinAppendixCafterthefirstsignthatexistingBMPsareineffectiveorfailing.ListanddescribeBMPs:HighVisibilityPlasticorMetalFence(BMPCl03)SiltFence(EMPC223)InstallationSchedules:Installationwilloccurbeforeallotheractivity.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage4 2.t2Element2:EstablishConstructionAccessConstructionaccessoractivitiesoccurringonunpavedareaswillbeminimized,yetwherenecessary,accesspointsshallbestabilizedtominimizethetrackingofsedimentontopublicroads,andwheelwashing,streetsweeping,andstreetcleaningshallbeemployedtopreventsedimentfromenteringstatewaters.Allwashwastewatershallbecontrolledonsite.AstabilizedconstructionentrancewillbeplacedalongtheproposedSmithersAvenueright-of-wayandtheprojectwillutilizetheexistingasphalt/graveldrivewayfrom102dAveSE.ListanddescribeBMPs:StabilizedConstructionEntrance(BMPC105)ConstructionRoad/ParkingAreaStabilization(BMPCl07)InstallationSchedules:Installationwilloccuraftertheclearinglimitsaremarked.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage5 2.t3Element3:ControlFlowRatesInordertoprotectthepropertiesandwaterwaysdownstreamoftheprojectsite,stormwaterdischargesfromthesitewillbecontrolled.ThespecificBMPsforflowcontrolthatshallbeusedonthisprojectinclude:.SedimentTrap(BMP0240)TwoSedimentTrapswillbeutilizedduringconstructionasaflowcontrolandsedimentationdevice.Thenorthernsedimenttrapwillpumpstormwatertotheproposedoutfallconveyancesystem.Thesouthernsedimenttrapwilloverflowrunoffintotheproposedtreeretentiontract.AlternateflowcontrolBMPsareincludedinAppendixCasaquickreferencetoolfortheonsiteinspectorintheeventtheBMP(s)listedabovearedeemedineffectiveorinappropriateduringconstructiontosatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD).Toavoidpotentialerosionandsedimentcontrolissuesthatmaycauseaviolation(s)oftheNPDESConstructionStormwaterpermit(asprovidedinAppendixD),theCertifiedErosionandSedimentControlLeadwillpromptlyinitiatetheimplementationofoneormoreofthealternativeBMPslistedinAppendixCafterthefirstsignthatexistingBMPsareineffectiveorfailing.TheprojectsiteislocatedwestoftheCascadeMountainCrest.Assuch,theprojectmustcomplywithMinimumRequirement7(Ecology2005).Ingeneral,dischargeratesofstormwaterfromthesitewillbecontrolledwhereincreasesinimperviousareaorsoilcompactionduringconstructioncouldleadtodownstreamerosion,orwherenecessarytomeetlocalagencystormwaterdischargerequirements(e.g.dischargetocombinedsewersystems).Willyouconstructstormwaterretentionand/ordetentionfacilities?YesLINoWillyouusepermanentinfiltrationpondsorotherlowimpactdevelopment(example:raingardens,bio-retention,porouspavement)tocontrolflowduringconstruction?ElYesNoListanddescribeBMPs:SedimentTraps(BMPC240)BakerTanks(Asnecessary)InstallationSchedules:Installationwilloccurbeforeanygradingoccurs.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage6 2.1.4Element4:InstallSedimentControlsSiltfencewillbeinstalledaroundtheperimeteroftheSiteinareaswhererunoffcouldsheet-flowoffsite.ThisBMPwillbeinstalledatthestartofconstruction.Theinterceptorswaleswillbeinstalledduringsitegrading.Theinterceptorswaleswillbedirectedtowardsthesedimenttraps.AlternatesedimentcontrolBMPsareincludedinAppendixCasaquickreferencetoolfortheonsiteinspectorintheeventtheBMP(s)listedabovearedeemedineffectiveorinappropriateduringconstructiontosatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD).Toavoidpotentialerosionandsedimentcontrolissuesthatmaycauseaviolation(s)oftheNPDESConstructionStormwaterpermit(asprovidedinAppendixD),theCertifiedErosionandSedimentControlLeadwillpromptlyinitiatetheimplementationofoneormoreofthealternativeBMPslistedinAppendixCafterthefirstsignthatexistingBMPsareineffectiveorfailing.Inaddition,sedimentwillberemovedfrompavedareasinandadjacenttoconstructionworkareasmanuallyorusingmechanicalsweepers,asneeded,tominimizetrackingofsedimentsonvehicletiresawayfromthesiteandtominimizewashoffofsedimentsfromadjacentstreetsinrunoff.Wheneverpossible,sedimentladenwatershallbedischargedintoonsite,relativelylevel,vegetatedareas(BMPC240paragraph5,page4-102).Insomecases,sedimentdischargeinconcentratedrunoffcanbecontrolledusingpermanentstormwaterBMPs(e.g.,infiltrationswales,ponds,trenches).SedimentloadscanlimittheeffectivenessofsomepermanentstormwaterBMPs,suchasthoseusedforinfiltrationorbiofiltration;however,thoseBMPsdesignedtoremovesolidsbysettling(wetpondsordetentionponds)canbeusedduringtheconstructionphase.WhenpermanentstormwaterBMPswillbeusedtocontrolsedimentdischargeduringconstruction,thestructurewillbeprotectedfromexcessivesedimentationwithadequateerosionandsedimentcontrolBMPs.AnyaccumulatedsedimentshallberemovedafterconstructioniscompleteandthepermanentstormwaterBMPwillberestabilizedwithvegetationperapplicabledesignrequirementsoncetheremainderofthesitehasbeenstabilized.ThefollowingBMPswillbeimplementedasend-of-pipesedimentcontrolsasrequiredtomeetpermittedturbiditylimitsinthesitedischarge(s).Priortotheimplementationofthesetechnologies,sedimentsourcesanderosioncontrolandsoilstabilizationBMPeffortswillbemaximizedtoreducetheneedforend-of-pipesedimentationcontrols.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage7 ListanddescribeBMPs:BakerTank(Asnecessary).....SiltFence(BMPC233).InterceptorSwale(BMP0200)InstallationSchedules:Thesewillallbeinstalledbeforeanygradingoccurs.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage8 2.1.5Element5:StabilizeSoilsTemporaryseedingandcovermeasuresmayberequiredforinterimgradingactivityandatsoilstockpilesandtheTemporarySedimentTraps.PermanentSeedingwilloccurasgradingiscompleted.Allstabilizedsectionswillbeseededandvegetated.NetsandBlanketsalongwithPlasticCoveringwillbeusedonallslopesof2:1asshownontheplan.DustControlwilloccurthroughoutthesiteasdeemednecessarybythecontractorandCESCL.AlternatesoilstabilizationBMPsareincludedinAppendixCasaquickreferencetoolfortheonsiteinspectorintheeventtheBMP(s)listedabovearedeemedineffectiveorinappropriateduringconstructiontosatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD).Toavoidpotentialerosionandsedimentcontrolissuesthatmaycauseaviolation(s)oftheNPDESConstructionStormwaterpermit(asprovidedinAppendixD),theCertifiedErosionandSedimentControlLeadwillpromptlyinitiatetheimplementationofoneormoreofthealternativeBMPslistedinAppendixCafterthefirstsignthatexistingBMPsareineffectiveorfailing.Ingeneral,cutandfillslopeswillbestabilizedassoonaspossibleandsoilstockpileswillbetemporarilycoveredwithplasticsheeting.Allstockpiledsoilsshallbestabilizedfromerosion,protectedwithsedimenttrappingmeasures,andwherepossible,belocatedawayfromstormdraininlets,waterways,anddrainagechannels.WestoftheCascadeMountainsCrestNumberofDaysSoilsCanSeasonDatesbeLeftExposedDuringtheDrySeasonMayI—September307daysDuringtheWetSeasonOctoberl—April302daysSoilsmustbestabilizedattheendoftheshiftbeforeaholidayorweekendifneededbasedontheweatherforecast.Anticipatedprojectdates:Startdate:TBDEnddate:TBDWillyouconstructduringthewetseason?YesLNoListanddescribeBMPs:TemporaryandPermanentSeeding(BMPC120)NetsandBlankets(BMPC122)PlasticCovering(BMPC123)DustControl(BMPC140)InstallationSchedules:Thesewillallbeinstalledbeforeanygradingoccurs.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortP1stStormwaterPollutionPreventionPlanPage9 2.1.6Element6:ProtectSlopesTemporaryslopeprotectionmeasuresmayberequiredforinterimgradingactivityandatsoilstockpilesandtheTemporarySedimentTrap.PermanentSeedingwilloccurthroughoutthesiteasslopesarestabilized.NetsandBlanketsalongwithPlasticCoveringwillbeusedonallslopesof2:1asshownontheplan.ChecksDamswillbeinstalledevery50’asshownontheplan.AlternateslopeprotectionBMPsareincludedinAppendixCasaquickreferencetoolfortheonsiteinspectorintheeventtheBMP(s)listedabovearedeemedineffectiveorinappropriateduringconstructiontosatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD).Toavoidpotentialerosionandsedimentcontrolissuesthatmaycauseaviolation(s)oftheNPDESConstructionStormwaterpermit(asprovidedinAppendixD),theCertifiedErosionandSedimentControlLeadwillpromptlyinitiatetheimplementationofoneormoreofthealternativeBMPslistedinAppendixCafterthefirstsignthatexistingBMPsareineffectiveorfailing.Willsteepslopesbepresentatthesiteduringconstruction?YesLNoListanddescribeEMPs:TemporaryandPermanentSeeding(BMPC120)NetsandBlankets(BMPC122)PlasticCovering(BMPC123)CheckDams(BMPC207)InstallationSchedules:Ingeneral,cutandfillslopeswillbestabilizedassoonaspossibleandsoilstockpileswillbetemporarilycoveredwithplasticsheeting.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortP1stStormwaterPollutionPreventionPlanPage10 2.1.7Element7:ProtectDrainInletsAllstormdraininletsandculvertsmadeoperableduringconstructionshallbeprotectedtopreventunfilteredoruntreatedwaterfromenteringthedrainageconveyancesystem.However,thefirstpriorityistokeepallaccessroadscleanofsedimentandkeepstreetwashwaterseparatefromenteringstormdrainsuntiltreatmentcanbeprovided.StormDrainInletProtection(BMP0220)willbeimplementedforalldrainageinletsandculvertsthatcouldpotentiallybeimpactedbysediment-ladenrunoffonandneartheprojectsite.Thefollowinginletprotectionmeasureswillbeappliedonthisproject:.CatchBasinFiltersThereareseveralexistingcatchbasinswhichwillrequirefilters.IftheBMPoptionslistedabovearedeemedineffectiveorinappropriateduringconstructiontosatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD),orifnoBMPsarelistedabovebutdeemednecessaryduringconstruction,theCertifiedErosionandSedimentControlLeadshallimplementoneormoreofthealternativeBMPinletprotectionoptionslistedinAppendixC.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage11 2.1.8Element8:StabilizeChannelsandOutletsTheprojectwillnotdischargetoanyoutletsorchannels;therefore,noBMPsarerequired.Providestabilization,includingarmoringmaterial,adequatetopreventerosionofoutlets,adjacentstreambanks,slopes,anddownstreamreaches,willbeinstalledattheoutletsofallconveyancesystems.DR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage12 11.9Element9:ControlPollutantsAllpollutants,includingwastematerialsanddemolitiondebris,thatoccuronsiteshallbehandledanddisposedofinamannerthatdoesnotcausecontaminationofstormwater.Goodhousekeepingandpreventativemeasureswillbetakentoensurethatthesitewillbekeptclean,well-organized,andfreeofdebris.Ifrequired,BMPstobeimplementedtocontrolspecificsourcesofpollutantsarediscussedbelow.Vehicles,constructionequipment,and/orpetroleumproductstorage/dispensing:.Allvehicles,equipment,andpetroleumproductstorage/dispensingareaswillbeinspectedregularlytodetectanyleaksorspills,andtoidentifymaintenanceneedstopreventleaksorspills..On-sitefuelingtanksandpetroleumproductstoragecontainersshallincludesecondarycontainment.aSpillpreventionmeasures,suchasdrippans,willbeusedwhenconductingmaintenanceandrepairofvehiclesorequipment..Inordertoperformemergencyrepairsonsite,temporaryplasticwillbeplacedbeneathand,ifraining,overthevehicle..Contaminatedsurfacesshallbecleanedimmediatelyfollowinganydischargeorspillincident.Demolition:.Dustreleasedfromdemolishedsidewalks,buildings,orstwctureswillbecontrolledusingDustControlmeasures(BMPC140).aStormdraininletsvulnerabletostormwaterdischargecarryingdust,soil,ordebriswillbeprotectedusingStormDrainInletProtection(BMPC220asdescribedaboveforElement7)..ProcesswaterandslurryresultingfromsawcuttingandsurfacingoperationswillbepreventedfromenteringthewatersoftheStatebyimplementingSawcuttingandSurfacingPollutionPreventionmeasures(BMPCl52).Concreteandgrout:.ProcesswaterandslurryresultingfromconcreteworkwillbepreventedfromenteringthewatersoftheStatebyimplementingConcreteHandlingmeasures(BMPC151).Sanitarywastewater:.Portablesanitationfacilitieswillbefirmlysecured,regularlymaintained,andemptiedwhennecessary.SolidWaste:.Solidwastewillbestoredinsecure,clearlymarkedcontainers.Other:.OtherBMPswillbeadministeredasnecessarytoaddressanyadditionalpollutantsourcesonsite.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage13 TheprojectisnotexpectedtoexceedtheI320gallonstored-fuelthresholdthatrequiresdevelopingaSpillPrevention,Control,andCountermeasure(SPCC)PlanundertheFederalregulationsoftheCleanWaterAct(CWA).ListanddescribeBMPs:DustControlmeasures(BMPC140)ConcreteHandlingmeasures(BMPC151)SawcuttingandSurfacingPollutionPreventionmeasures(BMPC152)StormDrainInletProtection(BMPC220)InstallationSchedules:Immediatelyfollowingorinconjunctionwithactivities.InspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLWillmaintenance,fueling,and/orrepairofheavyequipmentandvehiclesoccuron-site?LZIYesNoListanddescribeEMPs:N/AInstallationSchedules:N/AInspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLWillwheelwashortirebathsystemBMPsbeusedduringconstruction?EYesjNoListanddescribeBMPs:Presentlynotanticipated.SWPPPtobeamendedifwheelwashprovesnecessary.InstallationSchedules:TBDInspectionandMaintenanceplan:WeeklyResponsibleStaff:CESCLWillpH-modifyingsourcesbepresenton-site?D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortP1stStormwaterPollutionPreventionPlanPage14 YesENoTable3—pH-ModifyingSourcesUUUUUNUULINUUListanddescribeBMPs:WashwatertobecontainedandroutedtoBakerTank.SpecificpHtreatmentmeasurestobedeterminedbycontractorandCECSL.Presently,CO2spargingordryiceanticipatedapproachifpHmustbealtered.InstallationSchedules:priortoplacementofconcreteInspectionandMaintenanceplan:Monitoringwilloccuratthetimeofconcretewashoperations.ResponsibleStaff:CESCLConcretetrucksmustnotbewashedoutontotheground,orintostormdrains,openditches,streets,orstreams.Excessconcretemustnotbedumpedon-site,exceptindesignatedconcretewashoutareaswithappropriateBMPsinstalled.D.R.STRONGConsultingEngineers,Inc.StormwaterPollutionPreventionPlanVuecrestEstates&VuecrestIIShortPlatNoneBulkcementCementkilndustFlyash,-OthercementitiousmaterialsNewconcretewashingorcuringwatersWastestreamsgeneratedfromconcretegrindingandsawingExposedaggregateprocessesDewateringconcretevaultsConcretepumpingandmixerwashoutwatersRecycledconcreteOther(i.e.,calciumlignosulfate)[pleasedescribe:Page15 2.1.10Element10:ControlDewateringTherewillbenodewateringaspartofthisconstructionproject.Ifexcavationresultsintherequirementofdewatering,thisSWPPPcanbemodifiedtoincludedewateringmeasuresincludingcontrolofdischargewaters.DR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage16 2.1.11ElementII:MaintainBMPsAlltemporaryandpermanentErosionandSedimentControl(ESC)BMPsshallbemaintainedandrepairedasneededtoensurecontinuedperformanceoftheirintendedfunction.MaintenanceandrepairshallbeconductedinaccordancewitheachparticularBMPspecification(seeVolumeIIoftheSWMMWWorChapter7oftheSWMMEW).VisualmonitoringofallBMPsinstalledatthesitewillbeconductedatleastonceeverycalendarweekandwithin24hoursofanystormwaterornon-stormwaterdischargefromthesite.Ifthesitebecomesinactiveandistemporarilystabilized,theinspectionfrequencymaybereducedtoonceeverycalendarmonth.AlltemporaryESCBMPsshallberemovedwithin30daysafterfinalsitestabilizationisachievedorafterthetemporaryBMPsarenolongerneeded.Trappedsedimentshallbestabilizedon-siteorremoved.DisturbedsoilresultingfromremovalofeitherBMPsorvegetationshallbepermanentlystabilized.Additionally,protectionmustbeprovidedforallBMPsinstalledforthepermanentcontrolofstormwaterfromsedimentandcompaction.BMPsthataretoremaininplacefollowingcompletionofconstructionshallbeexaminedandrestoredtofulloperatingcondition.IfsedimententerstheseBMPsduringconstruction,thesedimentshallberemovedandthefacilityshallbereturnedtoconditionsspecifiedintheconstructiondocuments.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage17 2.1.12Element12:ManagetheProjectProjectmanagementwillincorporatethekeycomponentslistedbelow:Table5—ManagementNrNNNNNUAsthisprojectsiteislocatedwestoftheCascadeMountainCrest,theprojectwillbemanagedaccordingtothefollowingkeyprojectcomponents:PhasingofConstruction.Theconstructionprojectisbeingphasedtotheextentpracticableinordertopreventsoilerosion,and,tothemaximumextentpossible,thetransportofsedimentfromthesiteduringconstruction..Revegetationofexposedareasandmaintenanceofthatvegetationshallbeanintegralpartoftheclearingactivitiesduringeachphaseofconstruction,pertheSchedulingBMP(C162).SeasonalWorkLimitations.FromOctober1throughApril30,clearing,grading,andothersoildisturbingactivitiesshallonlybepermittedifshowntothesatisfactionofthelocalpermittingauthoritythatsilt-ladenrunoffwillbepreventedfromleavingthesitethroughacombinationofthefollowing:0Siteconditionsincludingexistingvegetativecoverage,slope,soiltype,andproximitytoreceivingwaters;and0Limitationsonactivitiesandtheextentofdisturbedareas;and0Proposederosionandsedimentcontrolmeasures..Basedontheinformationprovidedand/orlocalweatherconditions,thelocalpermittingauthoritymayexpandorrestricttheseasonallimitationonsitedisturbance..Thefollowingactivitiesareexemptfromtheseasonalclearingandgradinglimitations:0RoutinemaintenanceandnecessaryrepairoferosionandsedimentcontrolBMPs;0Routinemaintenanceofpublicfacilitiesorexistingutilitystructuresthatdonotexposethesoilorresultintheremovalofthevegetativecovertosoil;and0Activitieswherethereis100percentinfiltrationofsurfacewaterrunoffwithinthesiteinapprovedandinstallederosionandsedimentcontrolfacilities.DR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortP1stStormwaterPollutionPreventionPlanDesigntheprojecttofittheexistingtopography,soils,anddrainagepatternsEmphasizeerosioncontrolratherthansedimentcontrolMinimizetheextentanddurationoftheareaexposedKeeprunoffvelocitieslowRetainsedimenton-siteThoroughlymonitorsiteandmaintainallESCmeasuresSchedulemajorearthworkduringthedryseasonOther(pleasedescribe)Page18 CoordinationwithUtilitiesandOtherJurisdictionsaCarehasbeentakentocoordinatewithutilities,otherconstructionprojects,andthelocaljurisdictioninpreparingthisSWPPPandschedulingtheconstructionwork.InspectionandMonitoring.AllBMPsshallbeinspected,maintained,andrepairedasneededtoassurecontinuedperformanceoftheirintendedfunction.Siteinspectionsshallbeconductedbyapersonwhoisknowledgeableintheprinciplesandpracticesoferosionandsedimentcontrol.Thispersonhasthenecessaryskillsto:0Assessthesiteconditionsandconstructionactivitiesthatcouldimpactthequalityofstormwater,and0Assesstheeffectivenessoferosionandsedimentcontrolmeasuresusedtocontrolthequalityofstormwaterdischarges..ACertifiedErosionandSedimentControlLeadshallbeon-siteoron-callatalltimes..Wheneverinspectionand/ormonitoringrevealsthattheBMPsidentifiedinthisSWPPPareinadequate,duetotheactualdischargeoforpotentialtodischargeasignificantamountofanypollutant,appropriateBMPsordesignchangesshallbeimplementedassoonaspossible.MaintaininganUpdatedConstructionSWPPP.ThisSWPPPshallberetainedon-siteorwithinreasonableaccesstothesite..TheSWPPPshallbemodifiedwheneverthereisachangeinthedesign,construction,operation,ormaintenanceattheconstructionsitethathas,orcouldhave,asignificanteffectonthedischargeofpollutantstowatersofthestate..TheSWPPPshallbemodifiedif,duringinspectionsorinvestigationsconductedbytheowner/operator,ortheapplicablelocalorstateregulatoryauthority,itisdeterminedthattheSWPPPisineffectiveineliminatingorsignificantlyminimizingpollutantsinstormwaterdischargesfromthesite.TheSWPPPshallbemodifiedasnecessarytoincludeadditionalormodifiedBMPsdesignedtocorrectproblemsidentified.RevisionstotheSWPPPshallbecompletedwithinseven(7)daysfollowingtheinspection..IfBMP(s)aredeemeddonotsatisfytherequirementssetforthintheGeneralNPDESPermit(AppendixD),theCESCLwillpromptlyimplementoneormoreofthealternativeBMPslistedinAppendixCafterthefirstsignthatexistingBMPsareineffectiveorfailing..SiteinspectionsandmonitoringwillbeconductedinaccordancewithSpecialCondition54oftheCSWGP.Samplingwilloccuratthebakertankdischargepiping..TheSWPPPwillbeupdated,maintained,andimplementedinaccordancewithSpecialConditions$3,S4,and$9oftheCSWGP..AssiteworkprogressestheSWPPPwillbemodifiedroutinelytoreflectchangingsiteconditions.TheSWPPPwillbereviewedmonthlytoensurethecontentiscurrent..Uponrequest,contractorshallprovidetheDOEandCityofSammamishwithcurrentSWPPP.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage19 3PollutionPreventionTeamTable7—TeamInformationTitleName(s)PhoneNumberCertifiedErosionandEarthSolutionsNW,LLC4252843300SedimentControlLead(CESCL)ResidentEngineerMaherA.Joudi,PE425-827-3063EmergencyEcologyHowardZorzi425-649-7130ContactEmergencyPermittee/JamieWaltier206-315-8130OwnerContactNon-EmergencyOwnerJamieWaltier206-315-8130ContactMonitoringPersonnelEarthSolutionsNW,LLC425.284.3300EcologyRegionalOfficeNorthwestRegionalOffice425-649-7000CitySpillHotline(8:00amto425-295-05005:00pm)KingCountySpillHotline206-296-8100(AfterHours)D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage20 4MonitoringandSamplingRequirementsMonitoringincludesvisualinspection,samplingforwaterqualityparametersofconcern,anddocumentationoftheinspectionandsamplingfindingsinasitelogbook.Asitelogbookwillbemaintainedforallon-siteconstructionactivitiesandwillinclude:.ArecordoftheimplementationoftheSWPPPandotherpermitrequirements.Siteinspections.StormwatersamplingdataFileablankformunderAppendixD.Thesitelogbookmustbemaintainedon-sitewithinreasonableaccesstothesiteandbemadeavailableuponrequesttoEcologyorthelocaljurisdiction.Numericeffluentlimitsmayberequiredforcertaindischargesto303(d)listedwaterbodies.SeeCSWGPSpecialCondition58andSection5ofthistemplate.4.1SiteInspectionAllBMPswillbeinspected,maintained,andrepairedasneededtoassurecontinuedperformanceoftheirintendedfunction.TheinspectorwillbeaCertifiedErosionandSedimentControlLead(CESCL)perBMPC160.ThenameandcontactinformationfortheCESCLisprovidedinSection3ofthisSWPPP.Siteinspectionwilloccurinallareasdisturbedbyconstructionactivitiesandatallstormwaterdischargepoints.Stormwaterwillbeexaminedforthepresenceofsuspendedsediment,turbidity,discoloration,andoilysheen.ThesiteinspectorwillevaluateanddocumenttheeffectivenessoftheinstalledBMPsanddetermineifitisnecessarytorepairorreplaceanyoftheBMPstoimprovethequalityofstormwaterdischarges.Allmaintenanceandrepairswillbedocumentedinthesitelogbookorformsprovidedinthisdocument.AllnewBMPsordesignchangeswillbedocumentedintheSWPPPassoonaspossible.Siteinspectionswillbeconductedatleastonceeverycalendarweekandwithin24hoursfollowinganydischargefromthesite.Forsitesthataretemporarilystabilizedandinactive,therequiredfrequencyisreducedtooncepercalendarmonth.Theprojectdoesnotanticipatetodischargeanystormwater.ThesiteinspectorwillrecordeachsiteinspectionusingthesiteloginspectionformsprovidedinAppendixE.ThesiteinspectionlogformsmaybeseparatedfromthisSWPPPdocument,butwillbemaintainedon-siteorwithinreasonableaccesstothesiteandbemadeavailableuponrequesttoEcologyorthelocaljurisdiction.4.2StormwaterQualitySamplingRunoffwillbecollectedandconveyedtotheproposedinfiltrationfacilityinTractA,precededbyawetbiofiltrationswaletoaccommodateBasicWaterQualityrequirements.TheprojectwillD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage21 infiltrate100%ofthestormwatergenerated;howevertestingwilloccurasdeemednecessarybytheCESCLandtheexistingdownstreamcatchbasins.4.2.1TurbiditySamplingRequirementsincludecalibratedturbiditymeterortransparencytubetosamplesitedischargesforcompliancewiththeCSWGP.Samplingwillbeconductedatalldischargepointsatleastoncepercalendarweek.Methodforsamplingturbidity:Table8—TurbiditySamplingMethodETurbidityMeter/Turbidimeter(requiredfordisturbances5acresorgreaterinsize)TransparencyTube(optionfordisturbanceslessthan1acreandupto5acresinsize)Thebenchmarkforturbidityvalueis25nephelometricturbidityunits(NTU)andatransparencylessthan33centimeters.Ifthedischarge’sturbidityis26to249NTUjthetransparencyislessthan33cmbutequaltoorgreaterthan6cm,thefollowingstepswillbeconducted:1.ReviewtheSWPPPforcompliancewithSpecialCondition$9.Makeappropriaterevisionswithin7daysofthedatethedischargeexceededthebenchmark.2.Immediatelybegintheprocesstofullyimplementandmaintainappropriatesourcecontroland/ortreatmentBMPsassoonaspossible.Addresstheproblemswithin10daysofthedatethedischargeexceededthebenchmark.IfinstallationofnecessarytreatmentBMPsisnotfeasiblewithinI0days,EcologymayapproveadditionaltimewhenthePermitteerequestsanextensionwithintheinitial10-dayresponseperiod.3.DocumentBMPimplementationandmaintenanceinthesitelogbook.Iftheturbidityexceeds250NTUorthetransparencyis6cmorlessatanytime,thefollowingstepswillbeconducted:I.TelephonetheapplicableEcologyRegion’sEnvironmentalReportTrackingSystem(ERTS)numberwithin24hours..CentralRegion(Benton,Chelan,Douglas,Kittitas,Klickitat,Okanogan,Yakima):(509)575-2490.EasternRegion(Adams,Asotin,Columbia,Ferry,Franklin,Garfield,Grant,Lincoln,PendOreille,Spokane,Stevens,WallaWalla,Whitman):(509)329-3400.NorthwestRegion(King,Kitsap,Island,SanJuan,Skagit,Snohomish,Whatcom):(425)649-7000.SouthwestRegion(Clallam,Clark,Cowlitz,GraysHarbor,Jefferson,Lewis,Mason,Pacific,Pierce,Skamania,Thurston,Wahkiakum,):(360)407-63002.Immediatelybegintheprocesstofullyimplementandmaintainappropriatesourcecontroland/ortreatmentBMPsassoonaspossible.Addresstheproblemswithin10daysofthedatethedischargeexceededthebenchmark.IfinstallationofnecessaryD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage22 treatmentBMPsisnotfeasiblewithin10days,EcologymayapproveadditionaltimewhenthePermitteerequestsanextensionwithintheinitial10-dayresponseperiod3.DocumentBMPimplementationandmaintenanceinthesitelogbook.4.Continuetosampledischargesdailyuntiloneofthefollowingistrue:.Turbidityis25NTU(orlower)..Transparencyis33cm(orgreater)..Compliancewiththewaterqualitylimitforturbidityisachieved.01-5NTUoverbackgroundturbidity,ifbackgroundislessthan50NTU01%-10%overbackgroundturbidity,ifbackgroundis50NTUorgreater.Thedischargestopsoriseliminated.4.2.2pHSamplingpHmonitoringisrequiredfor‘Significantconcretework”(i.e.,greaterthan1000cubicyardspouredorrecycledconcreteoverthelifeoftheproject).Theuseofengineeredsoils(soilamendmentsincludingbutnotlimitedtoPortlandcement-treatedbase[CTB],cementkilndust[CKD]orflyash)alsorequirespHmonitoring.Forsignificantconcretework,pHsamplingwillstartthefirstdayconcreteispouredandcontinueuntilitiscured,typicallythree(3)weeksafterthelastpour.Forengineeredsoils,pHsamplingbeginswhenengineeredsoilsarefirstexposedtoprecipitationandcontinuesuntiltheareaisfullystabilized.IfthemeasuredpHis8.5orgreater,thefollowingmeasureswillbetaken:I.PreventhighpHwaterfromenteringstormsewersystemsorsurfacewater.2.AdjustorneutralizethehighpHwatertotherangeof6.5to8.5suusingappropriatetechnologysuchascarbondioxide(CC2)sparging(liquidordryice).3.WrittenapprovalwillbeobtainedfromEcologypriortotheuseofchemicaltreatmentotherthan002spargingordryice.MethodforsamplingpH:Table9—pHSamplingMethodEpHmeterEpHtestkitDWiderangepHindicatorpaperNot:pHmonitoringequipmentunknownatthistime;tobedeterminedbyCESCLD.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage23 5Dischargesto303(d)orTotalMaximumDailyLoad(TMDL)Waterbodies5.1303(U)ListedWaterbodiesIsthereceivingwater303(d)(Category5)listedforturbidity,finesediment,phosphorus,orpH?LIYesNoListtheimpairment(s):5.2TMDLWaterbodiesWasteLoadAllocationforCWSGPdischarges:ListanddescribeBMPs:DischargestoTMDLreceivingwaterbodieswillmeetin-streamwaterqualitycriteriaatthepointLofdischarge.TheConstructionStormwaterGeneralPermitProposedNewDischargetoanImpairedWaterBodyformisincludedinAppendixF.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPage24 gO6edUIdUOI1UOAOJduo!lnhIoUJ4MWJOj9e1dJOII1SGJ3flA‘soieis1SOJOOflA.3uI‘sJoou!6u36U!TIflSUODONOdIS•dGueA!6e6uinpe6JqospOUSMeieq41Aq}UOWi6OIO3]opewqnseqII!M(sda)sjoded6u!]o1!uoe6eqosi‘eiojeieqie6ieiioeie()auoSieoueqinsiplbseA!eIflWfl3spodeN6UUO!UOJe6ieipsiV96UiJOdeN9peiededeqII!MuoiieiueweidwidIAi9]OJeuew!peiepdnuveouejdwooiojkiesseoeueiesjpe!JIpowioeuo!ppeeu!wleTep(s)uo!186!TseAu!Jo(s)uopedsu!J!SAG3UiueiesU!q!Mpe!!poweq1PMdddMSeqeeseqJos]eeMOsTueTnhlodJOe6JeLpspequopejeTUeO!J!U6!Se‘eAeqiinooio‘seqeqesuo!lon.flsuOoeqeoueueu!ewio‘uo!1e]edo‘uopnsuoo‘u6sepue6ueqoeseeq.e!seqjWOJJSe6JeqOSpJ}MWJO}SU!SlUBiflhlod6U!z!w!u!wAIIUBO!J!U6!S.io6U!I8U!w!IeU!eA!loeJJeU!PUflOd:4!Pe!J!PoweqII!MdddMSeqdddMSeq6U!Bpdfl£•V9•dEMSDeqJo•D9SUO!}!PU0D12!3edS111!MeoepoooeU!6U!!]MU!pelsefibe]UeqMo!qfldeqj01pep!Ao]deqII!MdUUMSeqjo}sseooe]OaaawseqJOAdooyA6ojooWOJJTseflbeU8]MJOTd!eoejosApU!Lfl!Mpep!AwdeqII!MUo!lelUewfloop!wedN0096odddMS]ane7e6B]eAo3pwjeudDMSD:eps-UopeUieeJeqoUo!TeTUewfl3op!W]eddDMSDeqJOD99UO!!pUODIB!oeUSL.ll!Me3UBp]O33U!e68]eAOO1!weUoUO!leU!W]ejeq6U!MoIIoJseeA(c;)eeiqjjoWflW!U!W8]OJPU43e[OJdeqjoeqj6U!JflppeU!BTe]eqtI!MspooejUO!UOOspiooejV9s6oieidwe.sUo!l3edsU!epslUewal!nbej1!wJeUeqoPU8auuwseqjoUo!TelUeweIUw!eqiJOJO38]V:epflIoU!II!MpueS8i!A!38UO!3fl]SUO3eiS-UOflG]OJpeU!U!eweq11W’ooq6oesVNoo86ole;IS10V96U!dee)jpJo3e96uIdeeNp]OOOjpUE6uipode9 monitoringperiodtheDMRwillbesubmittedasrequired,reporting‘NoDischarge”.TheDMRduedateisfifteen(15)daysfollowingtheendofeachcalendarmonth.DMRswillbereportedonlinethroughEcology’sWQWebDMRSystem.6.2.2NotificationofNoncomplianceIfanyofthetermsandconditionsofthepermitisnotmet,andtheresultingnoncompliancemaycauseathreattohumanhealthortheenvironment,thefollowingactionswillbetaken:I.EcologywillbeimmediatelynotifiedofthefailuretocomplybycallingtheapplicableRegionalofficeERTSphonenumber(Regionalofficenumberslistedbelow).2.Immediateactionwillbetakentopreventthedischarge/pollutionorotherwisestoporcorrectthenoncompliance.Ifapplicable,samplingandanalysisofanynoncompliancewillberepeatedimmediatelyandtheresultssubmittedtoEcologywithinfive(5)daysofbecomingawareoftheviolation.3.AdetailedwrittenreportdescribingthenoncompliancewillbesubmittedtoEcologywithinfive(5)days,unlessrequestedearlierbyEcology.Anytimeturbiditysamplingindicatesturbidityis250NTUsorgreater,orwatertransparencyis6cmorless,theEcologyRegionalofficewillbenotifiedbyphonewithin24hoursofanalysisasrequiredbySpecialConditionS5.AoftheCSWGP..CentralRegionat(509)575-2490forBenton,Chelan,Douglas,Kittitas,Klickitat,Okanogan,orYakimaCounty.EasternRegionat(509)329-3400forAdams,Asotin,Columbia,Ferry,Franklin,Garfield,Grant,Lincoln,PendOreille,Spokane,Stevens,WallaWalla,orWhitmanCounty.NorthwestRegionat(425)649-7000forIsland,King,Kitsap,SanJuan,Skagit,Snohomish,orWhatcomCounty.SouthwestRegionat(360)407-6300forClallam,Clark,Cowlitz,GraysHarbor,Jefferson,Lewis,Mason,Pacific,Pierce,Skamania,Thurston,orWahkiakumIncludethefollowinginformation:1.Yournameand/Phonenumber2.Permitnumber3.CityICountyofproject4.Sampleresults5.Date/Timeofcall6.DateITimeofsample7.ProjectnameInaccordancewithSpecialConditionS4.D.5.boftheCSWGP,theEcologyRegionalofficewillbenotifiedifchemicaltreatmentotherthanCO2spargingisplannedforadjustmentofhighpHwater.DR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortP1stStormwaterPollutionPreventionPlanPage26 AppendixASiteMapDR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageA-i —-0-€-ccwsTRucncw5EQUNGEI’:(II0NQrHS&JECtACThSCftANU15x/U15xxxxxDRSPROECTNO.12102 EROSIONCONTROLNOTES&SPECIFICAflONSII0>SE7/4SECTION37.TOWNSHIP23N,RANGE5E,WM.VUECRESTESTATES&VUECRESTIISHORTPLAT—--•‘:-:::N-_‘fl”:”*,,,,,,,.::‘:.,,!=‘‘:‘-,,.‘*‘“S,‘‘-—.--,,,--:-“.-‘•“:;‘::E’”‘‘‘EEE AppendixBBMPDetailsDR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageB-I BMPClOl:PreservingNaturalVegetationPtiiposeThepurposeofpreservingnaturalvegetationistoreduceerosionwhereverpracticable.Limitingsitedisturbanceisthesinglemosteffectivemethodforreducingerosion.Forexample.coniferscanholduptoabout50ereentofallrainthatfallsduringastonmUpto20-30percentofthisrainmayneverreachthegroundbutistakenupbythetreeorevaporates.Anotherbenefitisthattherainheldinthetreecanbereleasedslowlytothegroundafterthestorm.ConditionsofUseNaturalvegetationshouldbepreservedonsteepslopes,nearperennialandintermittentwatercoursesorswales,andonbuildingsitesinwoodedareas..Asrequiredbylocalgovernments..Phaseconstructiontopreservenaturalvegetationontheprojectsiteforaslongaspossibleduringtheconstructionperiod.DesignandNaturalvegetationcanbepreservedinnaturalclumpsorasindividualInsta!latio,,trees,shrubsandvines.Specifications.....Thepreservationofindividualplantsismoredifficultbecauseheavyequipmentisgenerallyusedtoremoveunwantedvegetation.Thepointstorememberwhenattemptingtosaveindividualplantsare:.Istheplantworthsaving?Considerthelocation,species,size,age,vigor,andtheworkinvolved.Localgovernmentsmayalsohaveordinancestosavenaturalvegetationandtrees..Fenceorclearlymarkareasaroundtreesthataretobesaved.Itispreferabletokeepgrounddisturbanceawayfromthetreesatleastasfaroutasthedripline.Plantsneedprotectionfromthreekindsofinjuries:.Constructionuiment-Thisinjurycanbeaboveorbelowthegroundlevel.Damageresultsfromscarring,cuttingofroots,andcompactionofthesoil.Placingafencedbufferzonearoundplantstobesavedpriortoconstructioncanpreventconstructionequipmentinjuries..GraeCanes-Changingthenaturalgroundlevelwillaltergrades,whichaffectstheplant’sabilitytoobtainthenecessaryair,water,andminerals.Minorfillsusuallydonotcauseproblemsalthoughsensitivitybetweenspeciesdoesvaryandshouldbechecked.Treescantypicallytoleratefillof6inchesorless.Forshrubsandotherplants,thefillshouldbeless.Whentherearemajorchangesingrade,itmaybecomenecessarytosupplyairtotherootsofplants.Thiscanbedonebyplacingalayerofgravelandatilesystemovertherootsbeforethefillismade.Atilesystemprotectsatreefromaraisedgrade.ThetilesystemshouldbeoltimeConstructionStonnwaterPollutionFreentionuust2012 laidoutontheoriginalgradeleadingfromadrywellaroundthetreetrunk.Thesystemshouldthenbecoveredwithsmallstonestoallowairtocirculateovertherootarea.Loweringthenaturalgroundlevelcanseriouslydamagetreesandshrubs.Thehighestpercentageoftheplantrootsareintheupper12inchesofthesoilandcutsofonly2-3inchescancauseseriousinjury.Toprotecttherootsitmaybenecessarytoterracetheimmediateareaaroundtheplantstobesaved.ifrootsareexposed.constructionofretainingwallsmaybeneededtokeepthesoilinplace.Plantscanalsobepreservedbyleavingthemonanundisturbed,gentlyslopingmound.Toincreasethechancesforsurvival,itisbesttolimitgradechangesandothersoildisturbancestoareasoutsidethedriplineoftheplant.caations-Protecttreesandotherplantswhenexcavatingfordrainfields,power,water,andsewerlines.Wherepossible,thetrenchesshouldberoutedaroundtreesandlargeshrubs.Whenthisisnotpossible,itisbesttotunnelunderthem.Thiscanbedonewithhandtoolsorwithpoweraugers.Ifitisnotpossibletoroutethetrencharoundplantstobesaved,thenthefollowingshouldbeobserved:Cutasfewrootsaspossible.Whenyouhavetocut,cutclean.Paintcutrootendswithawooddressinglikeasphaltbasepaintifrootswillbeexposedformorethan24-hours.Backfillthetrenchassoonaspossible.Tunnelbeneathrootsystemsasclosetothecenterofthemaintrunktopreservemostoftheimportantfeederroots.Someproblemsthatcanbeencounteredwithafewspecifictreesare:Maple,Dogwood,Redalder,Westernhemlock,Westernredcedar,andDouglasfirdonotreadilyadjusttochangesinenvironmentandspecialcareshouldbetakentoprotectthesetrees.ThewindthrowhazardofPacificsilverfirandmadronaishigh,whilethatofWestemhemlockismoderate.Thedangerofwindthrowincreaseswheredensestandshavebeenthinned.Otherspecies(unlesstheyareonshallow,wetsoilslessthan20inchesdeep)havealowwindthrowhazard.Cottonwoods,maples,andwillowshavewater-seekingroots.Thesecancausetroubleinsewerlinesandinfiltrationfields.Ontheotherhand,theythriveinhighmoistureconditionsthatothertreeswouldnot.ThinningoperationsinpureormixedstandsofGrandfir,Pacificsilverfir,Noblefir,Sitkaspruce,Westernredcedar,Westernhemlock,Pacificdogwood,andRedaldercancauseseriousdiseaseproblems.Diseasecanbecomeestablishedthroughdamagedlimbs,trunks,roots,ohtnzeConstructionStormwaterPollutionPreentionuust2012 andfreshlycutstumps.Diseasedandweakenedtreesarealsosusceptibletoinsectattack.Maintenanceinspectflaggedand/orfenccdareasregularlytomakesureflaggingorStandardsfencinghasnotbeenremovedordamaged.Iftheflaggingorfencinghasbeendamagedorvisibilityreduced,itshallberepairedorreplacedimmediatelyandvisibilityrestored..Iftreerootshavebeenexposedorinjured,“prune”cleanlywithanappropriatepruningsaworlopersdirectlyabovethedamagedrootsandrecoverwithnativesoils.Treatmentofsapflowingtrees(fir,hemlock,pine,softmaples)isnotadvisedassapformsanaturalhealingbarrier.BMPC102:BufferZonesPiiiposeCreationofanundisturbedareaorstripofnaturalvegetationoranestablishedsuitableplantingthatwillprovidealivingfiltertoreducesoilerosionandrunoffvelocities.ConditionsofUseNaturalbufferzonesareusedalongstreams,wetlandsandotherbodiesofwaterthatneedprotectionfromerosionandsedimentation.Vegetativebufferzonescanbeusedtoprotectnaturalswalesandcanbeincorporatedintothenaturallandscapingofanarea.Critical-areasbufferzonesshouldnotbeusedassedimenttreatmentareas.Theseareasshallremaincompletelyundisturbed.Thelocalpermittingauthoritymayexpandthebufferwidthstemporarilytoallowtheuseoftheexpandedareaforremovalofsediment.Designand.Preservingnaturalvegetationorplantingsinclumps,blocks,orstripsInstallationisgenerallytheeasiestandmostsuccessfulmethod.Specifications..Leaveallunstablesteepslopesinnaturalvegetation..Markclearinglimitsandkeepallequipmentandconstructiondebrisoutofthenaturalareasandbufferzones.Steelconstructionfencingisthemosteffectivemethodinprotectingsensitiveareasandbuffers.Alternatively,wire-backedsiltfenceonsteelpostsismarginallyeffective.flaggingaloneistypicallynoteffective..Keepallexcavationsoutsidethedriplineoftreesandshrubs..Donotpushdebrisorextrasoilintothebufferzoneareabecauseitwillcausedamagefromburyingandsmothering..Vegetativebufferzonesforstreams,lakesorotherwaterwaysshallbeestablishedbythelocalpermittingauthorityorotherstateorfederalpermitsorapprovals.MaintenanceInspecttheareafrequentlytomakesureflaggingremainsinplaceandtheStandardsarearemainsundisturbed.Replacealldamagedflaggingimmediately.ohtmeConstructionStormwaterPollutionPreentionuust2012 BMPC103:HighVisibilityFencePitiposefencingisintendedto:1.Restrictclearingtoapprovedlimits.2.Preventdisturbanceofsensitiveareas,theirbtiffers,andotherareasrequiredtobeleftundisturbed.3.Limitconstructiontraffictodesignatedconstructionentrances,exits,orinternalroads.4.Protectareaswheremarkingwithsurveytapemaynotprovideadequateprotection.Co,iditionsofUseToestablishclearinglimitsplastic,fabric,ormetalfencemaybeused:.Attheboundaryofsensitiveareas,theirbuffers,andotherareasrequiredtobeleftuncleared..Asnecessarytocontrolvehicleaccesstoandonthesite.DesignandHighvisibilityplasticfenceshallbecomposedofahigh-densityInstallationpolyethylenematerialandshallbeatleastfourfeetinheight.PostsforSpecificationsthefencingshallbesteelorwoodandplacedevery6feetoncenter(maximum)orasneededtoensurerigidity.Thefencingshallbefastenedtotheposteverysixincheswithapolyethylenetie.Onlongcontinuouslengthsoffencing,atensionwireorropeshallbeusedasatopstringertopreventsaggingbetweenposts.Thefencecolorshallbehighvisibilityorange.Thefencetensilestrengthshallbe360lbs./ft.usingtheA$TMD4595testingmethod.IfappropriateinstallfabricsiltfenceinaccordancewithBMPC233toactashighvisibilityfence.Siltfenceshallbeatleast3feethighandmustbehighlyvisibletomeettherequirementsofthisBMP.Metalfencesshallbedesignedandinstalledaccordingtothemanufacturer’sspecifications.Metalfencesshallbeatleast3feethighandmustbehighlyvisible.fencesshallnotbewiredorstapledtotrees.MaintenanceIfthefencehasbeendamagedorvisibilityreduced,itshallberepairedorStandardsreplacedimmediatelyandvisibilityrestored.olumeConstructionStorrnwaterPollutionPreentionuust2012 BMPC105:StabilizedConstructionEntranceIExitPuiposeStabilizedConstructionentrancesarcestablishedtoreducetheamountofsedimenttransportedontopavedroadsbyvehiclesorequipment.Thisisdonebyconstructingastabilizedpadofquarryspallsatentrancesandexitsforconstructionsites.Co;;ditionsofUseConstructionentrancesshallbestabilizedwherevertrafficwillbeenteringorleavingaconstructionsiteifpavedroadsorotherpavedareasarewithin1,000feetofthesite.Forresidentialconstructionprovidestabilizedconstructionentrancesforeachresidence,ratherthanonlyatthemainsubdivisionentrance.Stabilizedsurfacesshallbeofsufficientlength/widthtoprovidevehicleaccess/parking,basedonlotsize/configuration.Onlargecommercial,highway,androadprojects,thedesignershouldincludeenoughextramaterialsinthecontracttoallowforadditionalstabilizedentrancesnotshownintheinitialConstructionSWPPP.Itisdifficulttodetenmineexactlywhereaccesstotheseprojectswilltakeplace;additionalmaterialswillenablethecontractortoinstallthemwhereneeded.DesigitandSeeFigure4.1.1fordetails.Note:the100’minimumlengthoftheInstallationentranceshallbereducedtothemaximumpracticablesizewhenthesizeSpecificatiolisorconfigurationofthesitedoesnotallowthefulllength(100’).Constructstabilizedconstructionentranceswitha12-inchthickpadof4-inchto8-inchquarryspalls,a4-inchcourseofasphalttreatedbase(ATB),oruseexistingpavement.Donotusecrushedconcrete,cement,orcalciumchlorideforconstructionentrancestabilizationbecausetheseproductsraisepHlevelsinstorrnwaterandconcretedischargetosurfacewatersoftheStateisprohibited.Aseparationgeotextileshallbeplacedunderthespallstopreventfinesedimentfrompumpingupintotherockpad.Thegeotextileshallmeetthefollowingstandards:GrabTensileStrength(ASTMD4751)200psimm.GrabTensileElongation(ASTM30%max.D4632)MullenBurstStrength(ASTM400psimm.D37$6-$Oa)AOS(ASTMD4751)20-45(U.S.standardsievesize).Considerearlyinstallationofthefirstliftofasphaltinareasthatwillpaved;thiscanbeusedasastabilizedentrance.Alsoconsidertheinstallationofexcessconcreteasastabilizedentrance.Duringlargeconcretepours,excessconcreteisoftenavailableforthispurpose.olumeConstructionStormwaterPollutionPreentioliuust2012 .Fencing(seeBMPC103)shallbeinstalledasnecessarytorestricttraffictotheconstructionentrance..Wheneverpossible.theentranceshallbeconstrtictedonafirm,compactedsubgradc.Thiscansubstantiallyincreasetheeffectivenessofthepadandreducetheneedformaintenance..Constructionentrancesshouldavoidcrossingexistingsidewalksandbackofwalkdrainsifatallpossible.Ifaconstructionentrancemustcrossasidewalkorbackofwalkdrain,thefulllengthofthesidewalkandbackofwalkdrainmustbecoveredandprotectedfromsedimentleavingthesite.MaintenanceQuarryspallsshallbeaddedifthepadisnolongerinaccordancewithStandardsthespecifications..Iftheentranceisnotpreventingsedimentfrombeingtrackedontopavement,thenalternativemeasurestokeepthestreetsfreeofsedimentshallbeused.Thismayincludereplacement/cleaningoftheexistingquarryspalls,streetsweeping,anincreaseinthedimensionsoftheentrance,ortheinstallationofawheelwash..Anysedimentthatistrackedontopavementshallberemovedbyshovelingorstreetsweeping.Thesedimentcollectedbysweepingshallberemovedorstabilizedonsite.Thepavementshallnotbecleanedbywashingdownthestreet,exceptwhenhighefficiencysweepingisineffectiveandthereisathreattopublicsafety.Ifitisnecessarytowashthestreets,theconstructionofasmallsumptocontainthewashwatershallbeconsidered.Thesedimentwouldthenbewashedintothesumpwhereitcanbecontrolled..Performstreetsweepingbyhandorwithahighefficiencysweeper.Donotuseanon-highefficiencymechanicalsweeperbecausethiscreatesdustandthrowssoilsintostormsystemsorconveyanceditches..Anyquarryspallsthatareloosenedfromthepad,whichendupontheroadwayshallberemovedimmediately..Ifvehiclesareenteringorexitingthesiteatpointsotherthantheconstructionentrance(s),fencing(seeBMPCl03)shallbeinstalledtocontroltraffic..Uponprojectcompletionandsitestabilization,allconstructionaccessesintendedaspermanentaccessformaintenanceshallbepermanentlystabilized.ohtmeConstructionStorrnwaterPollutionFreentionuust2012 Figure4.1.1—StabilizedConstructionEntranceApprovedasEquivalentEcologyhasapprovedproductsasabletomeettherequirementsofBMPCl05.TheproductsdidnotpassthroughtheTechnologyAssessmentProtocol—Ecology(TAPE)process.Localjurisdictionsmaychoosenottoacceptthisproductapprovedasequivalent,ormayrequireadditionaltestingpriortoconsiderationforlocaluse.TheproductsareavailableforreviewonEcology’swebsiteathttp:I/www.ecy.wa.gov/programs/wq/storrnwater/newtech/equivalent.htmlBMPC106:WheelWashPurposeConditionsofUseWheelwashesreducetheamountofsedimenttransportedontopavedroadsbymotorvehicles.Whenastabilizedconstructionentrance(seeBMPCl05)isnotpreventingsedimentfrombeingtrackedontopavement..WheelwashingisgenerallyaneffectiveBMPwheninstalledwithcarefulattentiontotopography.forexample,awheelwashcanbedetrimentalifinstalledatthetopofaslopeabuttingaright-of-waywherethewaterfromthedrippingtruckcanrununimpededintothestreet.DrivewayshallmeettherequirementsofthepermittingagencyItyrecommendedthattheentrancebecrownedsothatrunoffdrainsoffthepadInstalldrivewayculvertifthereisaroadsideditchpresent4•—8,quarspats—Geotextile.\_7±-;:>12mm.thickness______Providefullwidthofingress/egressareaolumeConstructionStonm4’aterPollutionPreentionuust2012 .Pressurewashingcombinedwithanadequatelysizedandsurfacedpadwithdirectdrainagetoalarge10-footx10-footsumpcanbevcryeffective..Dischargewheelwashortirebathwastewatertoaseparateon-sitetreatmentsystemthatpreventsdischargetosurfacewater,suchasclosed-looprecirculationoruplandlandapplication.ortothesanitarysewerwithlocalsewerdistrictapproval..Wheelwashortirebathwastewatershouldnotincludewastewaterfromconcretewashoutareas.DesignaiidSuggesteddetailsareshowninfigure4.1.2.TheLocalPermittingInstallatIonAuthoritymayallowotherdesigns.Aminimumof6inchesofasphaltSpecificationstreatedbase(ATB)overcrushedbasematerialor8inchesoveragoodsubgradeisrecommendedtopavethewheelwash.Usealowclearancetrucktotestthewheelwashbeforepaving.Eitherabellydumporlowboywillworkwelltotestclearance.Keepthewaterlevelfrom12to14inchesdeeptoavoiddamagetotruckhubsandfillingthetrucktongueswithwater.Midpointspraynozzlesareonlyneededinextremelymuddyconditions.Wheelwashsystemsshouldbedesignedwithasmallgradechange,6-to1-inchesfora10-foot-widepond,toallowsedimenttoflowtothelowsideofpondtohelppreventre-suspensionofsediment.Adrainpipewitha2-to3-footrisershouldbeinstalledonthelowsideofthepondtoallowforeasycleaningandrefilling.Polymersmaybeusedtopromotecoagulationandflocculationinaclosed-loopsystem.Polyacrylamide(PAM)addedtothewheelwashwateratarateof0.25-0.5poundsper1,000gallonsofwaterincreaseseffectivenessandreducescleanuptime.IfPAMisalreadybeingusedfordustorerosioncontrolandisbeingappliedbyawatertruck,thesametruckcanbeusedtochangethewashwater.MaintenanceThewheelwashshouldstartoutthedaywithfreshwater.StandardsThewashwatershouldbechangedaminimumofonceperday.Onlargeearthworkjobswheremorethan10-20trucksperhourareexpected,thewashwaterwillneedtobechangedmoreoften.ohimeConstructionStol7nwaterPollutionFreentionuust201210 Notes:2.3.4.Figure4.1.2—WheelWashAsphaltconstructionentrance6in.asphalttreatedbase(ATB).3-inchtrashpumpwithfloatsonthesuctionhose.Midpointspraynozzles,ifneeded.6-inchsewerpipewithbutterflyvalves.Bottomoneisadrain.Locatetoppipe’sinvert1footabovebottomofwheelwash.5.8footx8footsumpwith5feetofcatch.Buildsothesumpcanbecleanedwithatrackhoe.6.Asphaltcurbonthelowroadsidetodirectwaterbacktopond.7.6-inchsleeveunderroad.8.Ballvalves.9.15foot.ATBaprontoprotectgroundfromsplashingwater.olumeConstructionStormwaterPollutionFreention11Uust20126SEWERPIPEWITHBUTTERFLYVALVES—8x8SUMPWITH5OFCATCH2%SLOPE-3TRASHPUMPWITHFLOATSONSUCTIONHOSE2SCHEDULE401—1/2SCHEDULE40FORSPRAYERS•15’AThAPRONTOPROTECTGROUNDFROMSPLASHINGWATER-MIDPOINTSPRAYNOZZLESJIFNEEDED-2%SLOPE6SLEEVEUNDERI1515’IELANVIEW20’6ATBCONSTRUCTIONENTRANCEASPHALTCURBONTHELOWROADSIDETODIRECTWATERBACKTOPOND15’I50’[ELEVATIONVIEWi—.---—CURB-.%--%——6SLEEVELOCATEINVERTOFTOPPIPE1‘ABOVEBOTTOMOFWHEELWASH8’x8’SUMP18’DRAINPIPEISECT1ONA—AlNOTES:1:1SLOPE1.BUILD8’x8’SUMPTOACCOMODATECLEANiNGBYTRACKHOE. BMPC107:ConstructionRoad/ParkingAreaStabilizationPuiposeStabilizingsubdivisionroads,parkingareas,andotheron-sitevehicletransportationroutesimmediatelyaftergradingreduceserosioncausedbyconstructiontrafficorrunoff.Co;iditioi,sofUseRoadsorparkingareasshallbestabilizedwherevertheyareconstructed.whetherpermanentortemporary,forusebyconstructiontraffic..HighVisibilityfencing(seeBMPC103)shallbeinstalled,ifnecessary,tolimittheaccessofvehiclestoonlythoseroadsandparkingareasthatarestabilized.Designaiid•Onareasthatwillreceiveasphaltaspartoftheproject,installthefirstInstallationliftassoonaspossible.Specifications.•A6-inchdepthof2-to4-inchcrushedrock,gravelbase,orcrushedsurfacingbasecourseshallbeappliedimmediatelyaftergradingorutilityinstallation.A4-inchcourseofasphalttreatedbase(ATB)mayalsobeused,ortheroad/parkingareamaybepaved.Itmayalsobepossibletousecementorcalciumchlorideforsoilstabilization.Ifcementorcementkilndustisusedforroadbasestabilization,pHmonitoringandBMPs(BMPsC252andC253)arenecessarytoevaluateandminimizetheeffectsonstormwater.Iftheareawillnotbeusedforpermanentroads,parkingareas,orstructures,a6-inchdepthofhogfuelmayalsobeused,butthisislikelytorequiremoremaintenance.Wheneverpossible,constructionroadsandparkingareasshallbeplacedonafirm,compactedsubgrade.•Temporaryroadgradientsshallnotexceed15percent.Roadwaysshallbecarefullygradedtodrain.Drainageditchesshallbeprovidedoneachsideoftheroadwayinthecaseofacrownedsection,orononesideinthecaseofasuper-elevatedsection.DrainageditchesshallbedirectedtoasedimentcontrolBMP.•Ratherthanrelyingonditches,itmayalsobepossibletogradetheroadsothatrunoffsheet-flowsintoaheavilyvegetatedareawithawell-developedtopsoil.Landscapedareasarenotadequate.Ifthisareahasatleast50feetofvegetationthatwatercanflowthrough,thenitisgenerallypreferabletousethevegetationtotreatrunoff,ratherthanasedimentpondortrap.The50feetshallnotincludewetlandsortheirbuffers.Ifrunoffisallowedtosheetfiowthroughadjacentvegetatedareas,itisvitaltodesigntheroadwaysandparkingareassothatnoconcentratedrunoffiscreated.•Stormdraininletsshallbeprotectedtopreventsediment-ladenwaterenteringthestormdrainsystem(seeBMPC220).MainteitanceInspectstabilizedareasregularly,especiallyafterlargestormevents.Standards..Crushedrock,gravelbase,etc.shallbeaddedasrequiredtomamtamaolitmeConstructionStorinwaterPolhctionPreentioniiust201212 stabledrivingsurfaceandtostabilizeanyareasthathaveeroded.Followingconstruction,theseareasshallberestoredtopre-constructionconditionorbettertopreventfutureerosion.Performstreetcleaningattheendofeachdayormoreoftenifnecessary.BMPC120:TemporaryandPermanentSeedingPinposeSeedingreduceserosionbystabilizingexposedsoils.Awell-establishedvegetativecoverisoneofthemosteffectivemethodsofreducingerosion.ConditionsofUseUseseedingthroughouttheprojectondisturbedareasthathavereachedfinalgradeorthatwillremainunworkedformorethan30days.TheoptimumseedingwindowsforwesternWashingtonareApril1throughJune30andSeptember1throughOctober1.BetweenJuly1andAugust30seedingrequiresirrigationuntil75percentgrasscoverisestablished.BetweenOctober1andMarch30seedingrequiresacoverofmulchwithstraworanerosioncontrolblanketuntil75percentgrasscoverisestablished.ReviewalldisturbedareasinlateAugusttoearlySeptemberandcompleteallseedingbytheendofSeptember.Otherwise,vegetationwillnotestablishitselfenoughtoprovidemorethanaverageprotection..Mulchisrequiredatalltimesforseedingbecauseitprotectsseedsfromheat,moistureloss,andtransportduetorunoff.Mulchcanbeappliedontopoftheseedorsimultaneouslybyhydroseeding.SeeBMPC121:Mulchingforspecifications..Seedandmulch,alldisturbedareasnototherwisevegetatedatfinalsitestabilization.Finalstabilizationmeansthecompletionofallsoildisturbingactivitiesatthesiteandtheestablishmentofapermanentvegetativecover,orequivalentpermanentstabilizationmeasures(suchaspavement,riprap,gabionsorgeotextiles)whichwillpreventerosion.DesignandSeedretention/detentionpondsasrequired.Instai!atioii...InstallchannelsintendedforvegetationbeforestartingmajorSpecifications..earthworkandhydroseedwithaBondedFiberMatrix.forvegetatedchannelsthatwillhavehighflows,installerosioncontrolblanketsoverhydroseed.Beforeallowingwatertoflowinvegetatedchannels,establish75percentvegetationcover.Ifvegetatedchannelscannotbeestablishedbyseedbeforewaterflow;installsodinthechannelbottom—overhydromulchanderosioncontrolblankets.ohtmeConstructionStormwaterPollutionPreentionuust20121 Confirmtheinstallationofallrequiredsurfacewatercontrolmeasurestopreventseedfromwashingaway.Hydroseedapplicationsshallincludeaminimumof1,500poundsperacreofmulchwith3percenttackifier.SeeBMPCl2l:Mu1cingforspecifications..Areasthatwillhaveseedingonlyandnotlandscapingmayneed-compostormeal-basedmulchincludedinthehydroseedinordertoestablishvegetation.Re-installnativetopsoilonthedisturbedsoilsurfacebeforeapplication.Wheninstallingseedviahydroseedingoperations,onlyabout1/3oftheseedactuallyendsupincontactwiththesoilsurface.Thisreducestheabilitytoestablishagoodstandofgrassquickly.Toovercomethis,considerincreasingseedquantitiesbyupto50percent.Enhancevegetationestablishmentbydividingthehydrornuichoperationintotwophases:1.Phase1-Installallseedandfertilizerwith25-30percentmulchandtackifierontosoilinthefirstlift.2.Phase2-Installtherestofthemulchandtackifieroverthefirstlift.Or,enhancevegetationby:1.Installingthemulch,seed,fertilizer,andtackifierinonelift.2.Spreadorblowstrawoverthetopofthehydrornulchatarateof800-1000poundsperacre.3.Holdstrawinplacewithastandardtackifier.Bothoftheseapproacheswillincreasecostmoderatelybutwillgreatlyimproveandenhancevegetativeestablishment.Theincreasedcostmaybeoffsetbythereducedneedfor:.Irrigation..Reapplicationofmulch..Repairoffailedslopesurfaces.Thistechniqueworkswithstandardhydromuich(1,500poundsperacreminimum)andBFM/MBFMs(3,000poundsperacreminimum).Seedmaybeinstalledbyhandif:ITemporaryandcoveredbystraw,mulch,ortopsoil..Permanentinsmallareas(usuallylessthan1acre)andcoveredwithmulch,topsoil,orerosionblankets.Theseedmixeslistedinthetablesbelowincluderecommendedmixesforbothtemporaryandpermanentseeding.ohimeConstructionStorrnwaterPollutionPreentionuust20121 .Applytheseiiñxes,wjththeexceptionofthcwetlandmix,atarateof120poundsperacre.Thisratecanbefeducedifsoilamendmentsorslow-releasefertilizersareused..Consultthelocalsuppliersorthelocalconservationdistrictfortheirrecommendationsbecausetheappropriatemixdependsonavarietyoffactors,includinglocation,exposure,soiltype,slope,andexpectedfoottraffic.Alternativeseedmixesapprovedbythelocalauthoritymaybeused..Othermixesmaybeappropriate,dependingonthesoiltypeandhydrologyofthearea.Table4.1.2liststhestandardmixforareasrequiringatemporaryvegetativecover.Table4.1.2TemporaryErosionControlSeedMixwjPriGrinaionChewingsorannualbluegrass409890estucarubraarcommutataorFoaannaPerennialrye-509890oliuijierenneRedtoporcolonialbentgrass59285rostisalbaorrostistenuis___________________________Whitedutchclover59890rioliurnreensTable4.1.3listsarecommendedmixforlandscapingseed.Table4.1.3LandscapingSeedMixWIPriGrinalonPerennialryeblend709890oliumerenneChewingsandredfescueblend309890estucarubraarcommutataorestucarubraolumeConstructionStorrnwaterPollutionPreentionuust20121 Table4.1.4listsaturfseedmixfordrysituationswherethereisnoneedforwatering.Thismixrequiresverylittlemaintenance.Table4.1.4Low-GrowingTurfSeedMix\ijPriCrinalonDwarftallfescue(severalvarieties)459890estuca(XPUfliliaceaarDwarfperennialrye(Barclay)309890oliurnerennearbarciaRedfescue209890estztcarubraColonialbentgrass59890rostistenitisTable4.1.5listsamixforbioswalesandotherintermittentlywetareas.Table4.1.5BioswaleSeedMix*WIPriGrinaionTallormeadowfescue75-809890estucaarunmaccaorestitcaelatior____________________Seaside/Creepingbentgrass10-159285ro s t i s__ alu s t ris _______ _________________ ____Redtopbentgrass5-109080rostisa/baorrostisiantea0iieriarreen,iicroseeinGuieetlansSeeiolumeConstructionStormwaterPollutionPreentionUUSt20121 Table4.1.6listsalow-growing,relativelynon-invasiveseedmixappropriateforverywetareasthatarenotregulatedwetlands.Applythismixtureatarateof60poundsperacre.ConsultHydraulicPermitAuthority(HPA)forseedmixesifapplicable.Table4.1.6WetAreaSeedMix*vIPriGrinaionTallormeadowfescue60-709890estitcaaruninaceaorestticaelatiorSeaside/Creepingbentgrass10-159885rostisahistrisMeadowfoxtail10-159080leocurzisratensis___________________________ ___Alsikeclover1-6989011oliuiiibriurnRedtopbentgrass1-69285rostisa/ba01ieriarreeii,flCroseeinGuiect/ansSeeITable4.1.7listsarecommendedmeadowseedmixforinfrequentlymaintainedareasornon-maintainedareaswherecolonizationbynativeplantsisdesirable.Likelyapplicationsincluderuralroadandutilityright-of-way.SeedingshouldtakeplaceinSeptemberorveryearlyOctoberinordertoobtainadequateestablishmentpriortothewintermonths.Considertheappropriatenessofclover,afairlyinvasivespecies,inthemix.Amendingthesoilcanreducetheneedforclover.Table4.1.7MeadowSeedMixWIPriGrinaionRedtoporOregonbentgrass209285rostisa/baorrostisoreonensis_________________________Redfescue709890estucarubra__________________Whitedutchclover1098907.io/iurnreensolurneConstructionStorrnwaterPollutionPreentionuust20121 RofluandRooiinTheseedbedshouldbefirmandrough.Roughenallsoilnomatterwhattheslope.Trackwalkslopesbeforeseedingifengineeringpurposesrequirecompaction.Backbladingorsmoothingofslopesgreaterthan4H:1Visnotallowediftheyaretobeseeded.Restoration-basedlandscapepracticesrequiredeeperincorporationthanthatprovidedbyasimplesingle-passrototillingtreatment.Whereverpractical.initiallyripthesubgradetoimprovelong-termpermeability,infiltration,andwaterinflowqualities.Ataminimum,permanentareasshallusesoilamendmentstoachieveorganicmatterandpermeabilityperformancedefinedinengineeredsoil/landscapesystems.forsystemsthataredeeperthan8inchescompletetherototillingprocessinmultiplelifts,orpreparetheengineeredsoilsystemperspecificationsandplacetoachievethespecifieddepth.FrilrConductingsoilteststodeterminetheexacttypeandquantityoffertilizerisreconmiended.Thiswillpreventtheover-applicationoffertilizer.Organicmatteristhemostappropriateformoffertilizerbecauseitprovidesnutrients(includingnitrogen,phosphorus,andpotassium)intheleastwater-solubleform..Ingeneral,use10-4-6N-P-K(nitrogen-phosphorus-potassium)fertilizeratarateof90poundsperacre.Alwaysuseslow-releasefertilizersbecausetheyaremoreefficientandhavefewerenvironmentalimpacts.Donotaddfertilizertothehydromuichmachine,oragitate,morethan20minutesbeforeuse.Toomuchagitationdestroystheslow-releasecoating.Therearenumerousproductsavailablethattaketheplaceofchemicalfertilizers.Theseincludeseveralwithseaweedextractsthatarebeneficialtosoilmicrobesandorganisms.If100percentcottonseedmealisusedasthemulchinhydroseed,chemicalfertilizermaynotbenecessary.Cottonseedmealprovidesagoodsourceoflong-term,slow-release,availablenitrogen.BonddFlrMariandManiaBonddFlrMari.OnsteepslopesuseBondedFiberMatrix(BFM)orMechanicallyBondedFiberMatrix(MBFM)products.ApplyBFM/MBFMproductsataminimumrateof3,000poundsperacreofmulchwithapproximately10percenttackifier.Achieveaminimumof95percentsoilcoverageduringapplication.Numerousproductsareavailablecommercially.Installedproductspermanufacturer’sinstructions.Mostproductsrequire24-36hourstocurebeforerainfallandcannotbeinstalledonwetorsaturatedsoils.olitmeConstructionStorm4’aterPollutionFreentionuust20121 Generally,roductscomein40-50poundbagsandincludeallnecessaryingredientsexceptforseedandfertilizer..BFMsandMBFMsprovidegoodalternativestoblanketsinmostareasrequiringvegetationestablishment.Advantagesoverblanketsinclude:.BfMandMBFMsdonotrequirestirfacepreparation..HelicopterscanassistininstallingBfMandMBFMsinremoteareas..Onslopessteeperthan2.5H:1V,blanketinstallersmayrequireropesandharnessesforsafety..InstallingBFMandMBFMscansaveatleast$1,000peracrecomparedtoblankets.MabiteitanceReseedanyseededareasthatfailtoestablishatleast80percentcoverStandards(100percentcoverforareasthatreceivesheetorconcentratedflows).Ifreseedingisineffective,useanalternatemethodsuchassodding,mulching,ornets/blankets.Ifwinterweatherpreventsadequategrassgrowth,thistimelimitmayberelaxedatthediscretionofthelocalauthoritywhensensitiveareaswouldotherwisebeprotected..Reseedandprotectbymulchanyareasthatexperienceerosionafterachievingadequatecover.Reseedandprotectbymulchanyerodedarea..Supplyseededareaswithadequatemoisture,butdonotwatertotheextentthatitcausesrunoff.ApprovedasEcologyhasapprovedproductsasabletomeettherequirementsofBMPEquivalentC120.TheproductsdidnotpassthroughtheTechnologyAssessmentProtocol—Ecology(TAPE)process.Localjurisdictionsmaychoosenottoacceptthisproductapprovedasequivalent,ormayrequireadditionaltestingpriortoconsiderationforlocaluse.TheproductsareavailableforreviewonEcology’swebsiteathttpi/www.ecy.wa.gov/programs/wq/storrnwater/newtech/equivalent.htrnlBMPC121:MulchingPurposeMulchingsoilsprovidesimmediatetemporaryprotectionfromerosion.Mulchalsoenhancesplantestablishmentbyconservingmoisture,holdingfertilizer,seed,andtopsoilinplace,andmoderatingsoiltemperatures.Thereisanenormousvarietyofmulchesthatcanbeused.Thissectiondiscussesonlythemostcommontypesofmulch.Conditio,;sofUseAsatemporarycovermeasure,mulchshouldbeused:.forlessthan30daysondisturbedareasthatrequirecover.IAtalltimesforseededareas,especiallyduringthewetseasonandoltinieConstructionStornnvaterPollutionFreentionuust20121 duringthehotsummermonths..Duringthewetseasononslopessteeperthan3H:IVwithmorethan10feetofverticalrelief.Mulchmaybeappliedatanytimeoftheyearandmustberefreshedperiodically..Forseededareasmulchmaybemadeupof100percent:cottonseedmeal;fibersmadeofwood,recycledcellulose,hemp,kenaf:compost;orblendsofthese.Tackifiershallbeplant-based,suchasguaroralphaplantago,orchemical-basedsuchaspolyacrylamideorpolymers.Anymulchortackifierproductusedshallbeinstalledpermanufacturer’sinstructions.Generally,mulchescomein40-50poundbags.Seedandfertilizerareaddedattimeofapplication.DesignandFormulchmaterials,applicationrates,andspecifications,seeTable4.1.8.InstallationAlwaysusea2-inchminimummulchthickness;increasethethicknessSpecificationsuntilthegroundis95%covered(i.e.notvisibleunderthemulchlayer).Note:Thicknessmaybeincreasedfordisturbedareasinornearsensitiveareasorotherareashighlysusceptibletoerosion.Mulchusedwithintheordinaryhigh-watermarkofsurfacewatersshouldbeselectedtominimizepotentialflotationoforganicmatter.Compostedorganicmaterialshavehigherspecificgravities(densities)thanstraw,wood,orchippedmaterial.ConsultHydraulicPermitAuthority(HPA)formulchmixesifapplicable.Maintenance•Thethicknessofthecovermustbemaintained.StandardsAnyareasthatexperienceerosionshallberernuichedand/orprotectedwithanetorblanket.Iftheerosionproblemisdrainagerelated,thentheproblemshallbefixedandtheerodedarearemuiched.olitmeConstructionStorinwaterPollutionPreentionuust201220 Table4.1.8MulchStandardsandGuidelinesAlalon1/I1IanaQaiSandardRaRarStrawAir-dried:freefrom2-3’thick:5Cost-effectiveprotectionwhenappliedwithadeqtiatethickness.undesirableseedandbalesper1,000Hand-applicationgenerallyrequiresgreaterthicknessthancoarsematerial.sfor2-3tonsperblownstraw.Thethicknessofstrawmaybereducedbyhalfacrewhenusedinconjunctionwithseeding.Inwindyareasstrawmustbeheldinplacebycrimping.usingatackifler,orcoveringwithnetting.Blownstrawalwayshastobeheldinplacewithatackifierasevenlightwindswillblowitaway.Straw,however,hasseveraldeficienciesthatshouldbeconsideredwhenselectingmulchmaterials.Itoftenintroducesand/orencouragesthepropagationofweedspeciesandithasnosignificantlong-termbenefits.Itshouldalsonotbeusedwithintheordinaryhigh-waterelevationofsurfacewaters(duetoflotation).HydrornuichNogrowthApprox.25-30Shallbeappliedwithhydrornuicher.Shallnotbeusedwithoutinhibitingfactors.lbsper1,000sfseedandtackiflerunlesstheapplicationrateisatleastdoubled.or1,500-2,000Fiberslongerthanabout/4-linchcloghydromuichequipment.lbsperacreFibersshouldbekepttolessthan3/4inch.CompostedNovisiblewateror2”thickmm.;MoreeffectivecontrolcanbeobtainedbyincreasingthicknessMulchanddustduringapprox.100tonsto3”.ExcellentmulchforprotectingfinalgradesuntilComposthandling.Mustbeperacre(approx.landscapingbecauseitcanbedirectlyseededortilledintosoilproducedin800lbsperyard)asanamendment.Compostedmulchhasacoarsersizeaccordancewithgradationthancompost.ItismorestableandpracticaltouseinWAC173-350,wetareasandduringrainyweatherconditions.DonotuseSolidWaste.-compostedmulchnearwetlandsornearphosphorousimpairedHandlingStandards....waterbodies.ChippedSiteAveragesizeshall2’thickmm.;Thisisacost-effectivewaytodisposeofdebrisfromclearingVegetationbeseveralinches.andgrubbing,anditeliminatestheproblemsassociatedwithGradationsfromburning.Generally,itshouldnotbeusedonslopesabovefinesto6inchesinapprox.I0%becauseofitstendencytobetransportedbylengthfortexture,runoff.Itisnotrecommendedwithin200feetofsurfacewaters.variation,andIfseedingisexpectedshortlyaftermulch,thedecompositionofinterlockingthechippedvegetationmaytieupnutrientsimportanttograssproperties.establishment.Wood-basedNovisiblewateror2”thickmm.;Thismaterialisoftencalled“hogorhoggedfuel.”TheuseofMulchorWooddustduringapprox.100tonsmulchultimatelyimprovestheorganicmatterinthesoil.Strawhandling.Mustbeperacre(approx.Specialcautionisadvisedregardingthesourceandcompositionpurchasedfroma$00lbs.perofwood-basedmulches.ItspreparationtypicallydoesnotsupplierwithaSolidcubicyard)provideanyweedseedcontrol,soevidenceofresidualWasteHandlingvegetationinitscompositionorknowninclusionofweedplantsPermitoroneorseedsshouldbemonitoredandprevented(orminimized).exemptfromsolidwasteregulations.WoodStrandAblendofloose,2”thickmm.Cost-effectiveprotectionwhenappliedwithadequatethickness.Mulchlong,thinwoodAinitiiniuinof95-percentofthewoodstrandshallhavelengthspiecesderivedfrombet’Ween2and10-inches,withawidthandthicknessbetweennativeconiferor1/16and3/s-inches.Themulchshallnotcontainresin,tannin,ordeciduoustreeswithothercompoundsinquantitiesthatwouldbedetrimentaltoplanthighlength-to-widthlife.Sawdustorwoodshavingsshallnotbeusedasmulch.ratio.(WSDOTspecification(9-14.4(4))olumeConstructionSton;ni’aterPollutionFreentionuust201221 BMPC122:NetsandBlanketsPurposeErosioncontrolnetsandblanketsareintendedtopreventerosionandholdseedandnmlchinplaceonsteepslopesandinchanhelssothatvegetationcanbecomewellestablished.inaddition,somenetsandblanketscanbeusedtopemrnnentlyreinforceturftoprotectdrainagewaysduringhighflows.Nets(commonlycalledmatting)arestrandsofrnaterialwovenintoanopen,buthigh-tensilestrengthnet(forexample.coconutfibermatting).Blanketsarestrandsofmaterialthatarenottightlywoven,butinsteadformalayerofinterlockingfibers,typicallyheldtogetherbyabiodegradableorphotodegradablenetting(forexample,excelsiororstrawblankets).Theygenerall.yhavelowertensilestrengththannets,butcoverthegroundmorecompletely.Coir(coconutfiber)fabriccomesasbothnetsandblankets.ConditionsofUseErosioncontrolnetsandblanketsshouldbeused:.Toaidpermanentvegetatedstabilizationofslopes2H:1Vorgreaterandwithmorethan10feetofverticalrelief..Fordrainageditchesandswales(highlyrecommended).Theapplicationofappropriatenettingorblankettodrainageditchesandswalescanprotectbaresoilfromchannelizedrunoffwhilevegetationisestablished.Netsandblanketsalsocancaptureagreatdealofsedimentduetotheiropen,porousstructure.Netsandblanketscanbeusedtopermanentlystabilizechannelsandmayprovideacost-effective,environmentallypreferablealternativetoriprap.100percentsyntheticblanketsmanufacturedforuseinditchesmaybeeasilyreusedastemporaryditchliners.Disadvantagesofblanketsinclude:.Surfacepreparationrequired..Onslopessteeperthan2.5H:lv,blanketinstallersmayneedtoberopedandharnessedforsafety..Theycostatleast$4,000-6,000peracreinstalled.Advantagesofblanketsinclude:.Installationwithoutmobilizingspecialequipment..Installationbyanyonewithminimaltraining.Installationinstagesorphasesastheprojectprogresses..Installerscanhandplaceseedandfertilizerastheyprogressdowntheslope..Installationinanyweather..Therearenumeroustypesofblanketsthatcanbedesignedwithvariousparametersinmind.Thoseparametersinclude:fiberblend,meshstrength,longevity,biodegradability,cost,andavailability.olz.iineConstructionStorrnwaterPollutionPreentionuust201222 Designaitd•SeeFigure4.1.3andFigure4.1.4fortypicalorientationandInstallationinstallationofblanketsusedinchannelsandassopcprotection.Note:Specificcitiolisthesearetypicalonly;allblanketsmustbeinstalledpermanufacturer’sinstallationinstructions.•Installationiscriticaltotheeffectivenessoftheseproducts.Ifgoodgroundcontactisnotachieved,runoffcanconcentrateundertheproduct.resultinginsignificanterosion.•InstallationofBlanketsonSlopes:1.Comp’etefinalgradeandtrackwalkupanddowntheslope.2.Installhydromuichwithseedandfertilizer.3.Digasmalltrench,approximatelyI2incheswideby6inchesdeepalongthetopoftheslope.4.Installtheleadingedgeoftheblanketintothesmalltrenchandstapleapproximatelyevery18inches.NOTE:Staplesaremetal,“U”-shaped,andaminimumof6incheslong.Longerstaplesareusedinsandysoils.Biodegradablestakesarealsoavailable.5.Rolltheblanketslowlydowntheslopeasinstallerwalksbackwards.NOTE:Theblanketrestsagainsttheinstaller’slegs.Staplesareinstalledastheblanketisunrolled.Itiscriticalthattheproperstaplepatternisusedfortheblanketbeinginstalled.TheblanketisnottobeallowedtorolldOwntheslopeonitsownasthisstretchestheblanketmakingitimpossibletomaintainsoilcontact.Inaddition,nooneisallowedtowalkontheblanketafteritisinplace.6.Iftheblanketisnotlongenoughtocovertheentireslopelength,thetrailingedgeoftheupperblanketshouldoverlaptheleadingedgeofthelowerblanketandbestapled.Onsteeperslopes,thisoverlapshouldbeinstalledinasmalltrench,stapled,andcoveredwithsoil.•Withthevarietyofproductsavailable,itisimpossibletocoverallthedetailsofappropriateuseandinstallation.Therefore,itiscriticalthatthedesignengineerconsultthemanufacturer’sinformationandthatasitevisittakesplaceinordertoensurethattheproductspecifiedisappropriate.Informationisalsoavailableatthefollowingwebsites:1.W$DOT(Section3.2.4):http://www.wsdot.wa.gov/NR/rdonlyres/3B4IE087-FA86-4717-932D-D7A8556CCD5710/ErosionTrainingManual.pdf2.TexasTransportationInstitute:http://www.txdot.gov/business/doingbusiness/product_evaluationIerosioncontrol.htmolumeConstructionStol7nwaterPollutionPreentionuust20122 .Usejutemattinginconjunctionwithmulch(BMPC121).Excelsior,wovenstrawblanketsandcoir(coconutfiber)blanketsmaybeinstalledwithoutmulch.Therearemanyothertypesoferosioncontrolnetsandblanketsonthemarketthatmaybeappropriateincertaincircumstances..ingeneral,mostnets(e.g.,jutematting)requiremulchinordertopreventerosionbecausetheyhaveafairlyopenstructure.Blanketstypicallydonotrequiremulchbecausetheyusuallyprovidecompleteprotectionofthesurface..Extremelysteep,unstable,wet,orrockyslopesareoftenappropriatecandidatesforuseofsyntheticblankets,asareriverbanks,beachesandotherhigh-energyenvironments.Ifsyntheticblanketsareused,thesoilshouldbehydromuichedfirst..100-percentbiodegradableblanketsareavailableforuseinsensitiveareas.Theseorganicblanketsareusuallyheldtogetherwithapaperorfibermeshandstitchingwhichmaylastuptoayear..Mostnettingusedwithblanketsisphotodegradable,meaningtheybreakdownundersunlight(notUVstabilized).However,thisprocesscantakemonthsoryearsevenunderbrightsun.Oncevegetationisestablished,sunlightdoesnotreachthemesh.Itisnotuncommontofindnon-degradednettingstillinplaceseveralyearsafterinstallation.Thiscanbeaproblemifmaintenancerequirestheuseofrnowersorditchcleaningequipment.Inaddition,birdsandsmallanimalscanbecometrappedinthenetting.Maintenance•Maintaingoodcontactwiththeground.ErosionmustnotoccurStandardsbeneaththenetorblanket.•Repairandstapleanyareasofthenetorblanketthataredamagedornotinclosecontactwiththeground.•fixandprotecterodedareasiferosionoccursduetopoorlycontrolleddrainage.oltimeConstructionStorrnwaterPollutionPreentionuust20122 NOTES:1.Checkslotstobeconstructedpermanufacturersspecifications.2.Stakingorstaplinglayoutpermanufacturersspecifications.Figure4.1.3—ChannelInstallationFigure4.1.4—SlopeInstallation///N\///,%//t//////LYfr5omm)v//\\//\/’\//1r/x/>1F‘//\‘7<’v/(//c/K(/j\\\.\‘\\\ç\1ns)\‘\\\\\\\\\\\\InitialChannelAnchorTrenchIntermittentCheckSlotSlopesurfaceshallbesmoothbeforeplacementforpropersoilcontact.Staplingpatternaspermanufacturer’srecommendations.Mm.2”OverlapIfthereisabermatthetopofslope,anchorupslopeoftheberm.Mm.6overlap.Donotstretchblankets/mailingstight-allowtherollstomoldtoanyirregularities.Forslopeslessthan3H:IV,rollsmaybeplacedinhorizontalstrips.Stapleoverlapsmax.5’spacing.Bringmaterialdowntoalevelarea,turntheendunder4”andstapleat12”intervals.Lime,fertilize,andseedbeforeinstallation.Plantingofshrubs,trees,etc.Shouldoccurafterinstallation.olumeConstructionStormwaterPollutionPreentionuust20122 BMPC123:PlasticCoveringPuiposePlasticcoveringprovidesimmediate,short-termerosionprotectiontoslopesanddisturbedareas.ConditiojisofPlasticcoveringmaybeusedondisturbedareasthatrequirecoverUsemeasuresforlessthan30days,exceptasstatedbelow..Plasticisparticularlyusefulforprotectingcutandfillslopesandstockpiles.Note:Therelativelyrapidbreakdownofmostpolyethylenesheetingmakesitunsuitableforlong-term(greaterthansixmonths)applications..Duetorapidrunoffcausedbyplasticcovering,donotusethismethodupsiopeofareasthatmightbeadverselyimpactedbyconcentratedrunoff.Suchareasincludesteepand/orunstableslopes..Plasticsheetingmayresultinincreasedmnoffvolumesandvelocities,requiringadditionalon-sitemeasurestocounteracttheincreases.Creatingatroughwithwattlesorothermaterialcanconveycleanwaterawayfromtheseareas..Topreventundercutting,trenchandbackfillrolledplasticcoveringproducts..Whileplasticisinexpensivetopurchase,theaddedcostofinstallation,maintenance,removal,anddisposalmakethisanexpensivematerial,upto$1.50-2.00persquareyard..Wheneverplasticisusedtoprotectslopesinstallwatercollectionmeasuresatthebaseoftheslope.Thesemeasuresincludeplastic-coveredberms,channels,andpipesusedtocoveycleanrainwaterawayfrombaresoilanddisturbedareas.Donotmixcleanrunofffromaplasticcoveredslopewithdirtyrunofffromaproject..Otherusesforplasticinclude:1.Temporaryditchliner.2.Pondlinerintemporarysedimentpond.3.Linerforbermedtemporaryfuelstorageareaifplasticisnotreactivetothetypeoffuelbeingstored.4.Emergencyslopeprotectionduringheavyrains.5.Temporarydrainpipe(“elephanttrunk”)usedtodirectwater.Designand•Plasticslopecovermustbeinstalledasfollows:Installation1.Runplasticupanddownslope,notacrossslope.Specifications2.Plasticmaybeinstalledperpendiculartoaslopeiftheslopelengthislessthan10feet.3.Minimumof8-inchoverlapatseams.olumeConstructionStormwaterPollutionPreentioniiust20122 4.Onlongorwideslopes.orslopessubjecttowind,tapeallseams.5.Placeplasticintoasmall(I2-inchwideby6-inchdeep)slottrenchatthetopoftheslopeandbackfillwithsoiltokeepwaterfromflowingunderneath.6.Placesandfilledburlaporgeotextilebagsevery3to.6feetalongseamsandtiethemtogetherwithtwinetoholdtheminplace.7.Inspectplasticforrips,tears,andopenseamsregularlyandrepairimmediately.Thispreventshighvelocityrunofffromcontactingbaresoilwhichcausesextremeerosion.8.Sandbagsmaybeloweredintoplacetiedtoropes.However,allsandbagsmustbestakedinplace..Plasticsheetingshallhaveaminimumthicknessof0.06millimeters..Iferosionatthetoeofaslopeislikely,agravelberm,riprap,orothersuitableprotectionshallbeinstalledatthetoeoftheslopeinordertoreducethevelocityofrunoff.Mai,itena,;ce•Tornsheetsmustbereplacedandopenseamsrepaired.Standards....•Completelyremoveandreplacetheplasticifitbeginstodetenorateduetoultravioletradiation.•Completelyremoveplasticwhennolongerneeded.•Disposeofoldtiresusedtoweightdownplasticsheetingappropriately.ApprovedasEcologyhasapprovedproductsasabletomeettherequirementsofBMPEquivalentCl23.TheproductsdidnotpassthroughtheTechnologyAssessmentProtocol—Ecology(TAPE)process.Localjurisdictionsmaychoosenottoacceptthisproductapprovedasequivalent,ormayrequireadditionaltestingpriortoconsiderationforlocaluse.TheproductsareavailableforreviewonEcology’swebsiteathttp:/Iwww.ecy.wa.gov/programs/wq/stormwater/newtechleguivalent.htmlBMPCI24:SoddingPuiposeThepurposeofsoddingistoestablishpermanentturfforimmediateerosionprotectionandtostabilizedrainagewayswhereconcentratedoverlandflowwilloccur.CoitditionsofUseSoddingmaybeusedinthefollowingareas:IDisturbedareasthatrequireshort-termorlong-termcover.•Disturbedareasthatrequireimmediatevegetativecover.•Allwaterwaysthatrequirevegetativelining.Waterwaysmayalsobeseededratherthansodded,andprotectedwithanetorblanket.ohilneConstructionStorrnwaterPollutionFreentionuust20122 DesigiiandSodshallbefreeofweeds,ofuniformthickness(approximately1-inchInsttt!tationthick),andshallhaveadenserootmatformcclmnicalstrength.spc’ci:ticatioiis..Thefollowingstepsarereconmiendedforsodinstallation:.Shapeandsmooththesurfacetofinalgradeinaccordancewiththeapprovedgradingplan.Theswaleneedstobeoverexcavated4to6inchesbelowdesignelevationtoallowroomforplacingsoilamendmentandsod..Amend4inches(minimum)ofcornpostintothetop8inchesofthesoiliftheorganiccontentofthesoilislessthantenpercentorthepermeabilityislessthan0.6inchesperhour.See.http://www.ecy.wa.gov/prograrns/swfa/organics/soiLhtrnlforfurtherinformation..Fertilizeaccordingtothesupplier’srecommendations..WorklimeandfertilizerIto2inchesintothesoil,andsmooththesurface.aLaystripsofsodbeginningatthelowestareatobesoddedandperpendiculartothedirectionofwaterflow.Wedgestripssecurelyintoplace.Squaretheendsofeachstriptoprovideforaclose,tightfit.Staggerjointsatleast12inches.Stapleonslopessteeperthan3H:1V.Stapletheupstreamedgeofeachsodstrip.aRollthesoddedareaandirrigate.aWhensoddingiscarriedoutinalternatingstripsorotherpatterns,seedtheareasbetweenthesodimmediatelyaftersodding.Maintei;anceIfthegrassisunhealthy,thecauseshallbedeterminedandappropriateStaiidardsactiontakentoreestablishahealthygroundcover.Ifitisimpossibletoestablishahealthygroundcoverduetofrequentsaturation,instability,orsomeothercause,thesodshallberemoved,theareaseededwithanappropriatemix,andprotectedwithanetorblanket.BMPC125:TopsoilingICompostingPii;poseTopsoilingandcompostingprovideasuitablegrowthmediumforfinalsitestabilizationwithvegetation.Whilenotapermanentcoverpracticeinitself,topsoilingandcompostingareanintegralcomponentofprovidingpermanentcoverinthoseareaswherethereisanunsuitablesoilsurfaceforplantgrowth.UsethisBMPinconjunctionwithotherBMPssuchasseeding,mulching,orsodding.Nativesoilsanddisturbedsoilsthathavebeenorganicallyamendednotonlyretainmuchmorestormwater,buttheyalsoserveaseffectivebiofiltersforurbanpollutantsand,bysupportingmorevigorousplantgrowth,reducethewater,fertilizerandpesticidesneededtosupportolumeConstructionStonln%’aterPollutionPreentionuust20122 installedlandscapes.Topsoildoesnotincludeanysubsoilsbutoniythematerialfromthetopseveralinchesincludingorganicdebris.Coitditioiisof.PermanentlandscapedareasshallcontainhealthytopsoilthatreducesUsetheneedforfertilizers,improvesoveralltopsoilquality,providesforbettervegetalhealthandvitality,improveshydrologiccharacteristics,andreducestheneedforirrigation..Leavenativesoilsandthedufflayerundisturbedtothemaximumextentpracticable.Strippingofexisting.properlyfunctioningsoilsystemandvegetationforthepurposeoftopsoilingduringconstructionisnotacceptable.Preserveexistingsoilsystemsinundisturbedanduncompactedconditionsiffunctioningproperly..Areasthatalreadyhavegoodtopsoil,suchasundisturbedareas,donotrequiresoilamendments..Restore,tothemaximumextentpractical,nativesoilsdisturbedduringclearingandgradingtoaconditionequaltoorbetterthantheoriginalsitecondition’smoisture-holdingcapacity.Useon-sitenativetopsoil,incorporateamendmentsintoon-sitesoil,orimportblendedtopsoiltomeetthisrequirement.Topsoilingisarequiredprocedurewhenestablishingvegetationonshallowsoils,andsoilsofcriticallylowpH(highacid)levels.Bewareofwherethetopsoilcomesfrom,andwhatvegetationwasonsitebeforedisturbance,invasiveplantseedsmaybeincludedandcouldcauseproblemsforestablishingnativeplants,landscapedareas,orgrasses.Topsoilfromthesitewillcontainrnycorrhizalbacteriathatarenecessaryforhealthyrootgrowthandnutrienttransfer.Thesenativemycorrhizaareacclimatedtothesiteandwillprovideoptimumconditionsforestablishinggrasses.Usecommerciallyavailablernycorrhizaproductswhenusingoff-sitetopsoil.DesignaiidMeetthefollowingrequirementsforareasrequiringdisruptionandInstallationtopsoiling:Specifications•Maximizethedepthofthetopsoilwhereverpossibletoprovidethemaximumpossibleinfiltrationcapacityandbeneficialgrowthmedium.Topsoilshallhave:.Aminimumdepthof8-inches.Scarifysubsoilsbelowthetopsoillayeratleast4-incheswithsomeincorporationoftheuppermaterialtoavoidstratifiedlayers,wherefeasible.Rippingorrestructuringthesubgrademayalsoprovideadditionalbenefitsregardingtheoverallinfiltrationaridinterfiowdynamicsofthesoilsystem.olumeConstructionStorinwaterPollutionPreentionuust20122 .Aminimumorganiccontentof10%dryweight.and5%organicmattercontentinturfareas.Incorporateorganicamendmentstoaminimum8-inchdepthexceptwheretreerootsorothernaturalfeatureslimitthedepthofincorporation..ApHbetween6.0and8.0ormatchingthepHoftheundisturbedsoil..Ifblendedtopsoilisimported,thenfinesshouldbelimitedto25percentpassingthrougha200sieve.AccomplishtherequiredorganiccontentandpHbyeitherreturningnativetopsoiltothesiteand/orincorporatingorganicamendments..Tomeettheorganiccontentusecompostthatmeetsthedefinitionof”compostedmaterials”inWAC173-350-220.Thiscodeisavailableonlineat:http://apps.leg.wa.gov/WA.C/defauit.aspx?cite=173-350-220.Thecompostmustalsohaveanorganicmattercontentof35%to65%,andacarbontonitrogenratiobelow25H:1V.Thecarbontonitrogenratiomaybeashighas35H:1VforplantingscomposedentirelyofplantsnativetothePugetSoundLowlandsregion..Fortillsoilsuseamixtureofapproximatelytwopartssoiltoonepartcompost.Thisequatesto4inchesofcompostmixedtoadepthof12inchesintillsoils.Increasingtheconcentrationofcompostbeyondthislevelcanhavenegativeeffectsonvegetalhealth,whiledecreasingtheconcentrationscanreducethebenefitsofamendedsoils..Gravelorcobbleoutwashsoils,mayrequiredifferentapproaches.Organicsandfineseasilymigratethroughtheloosestructureofthesesoils.Therefore,theimportationofatleast6inchesofqualitytopsoil,underlainbysometypeoffilterfabrictopreventthemigrationoffines,maybemoreappropriateforthesesoils.Thefinalcompositionandconstructionofthesoilsystemwillresultinanaturalselectionorfavoringofcertainplantspeciesovertime.Forexample,incorporationoftopsoilmayfavorgrasses,whilelayeringwithmildlyacidic,high-carbonamendmentsmayfavormorewoodyvegetation.Allowsufficienttimeinschedulingfortopsoilspreadingpriortoseeding,sodding,orplanting.Takecarewhenapplyingtopsoiltosubsoilswithcontrastingtextures.Sandytopsoiloverclayeysubsoilisaparticularlypoorcombination,aswatercreepsalongthejunctionbetweenthesoillayersandcausesthetopsoiltoslough.Iftopsoilandsubsoilarenotproperlybonded,waterwillnotinfiltratethesoilprofileevenlyanditwillbedifficulttoohtmeConstructionStoriinraterPollutionPreentioniiust20120 .westablishvegetation.Thebestmethodtopreventalackofbondingistoactuallyworkthetopsoilintothelayerbelowforadepthofatleast6inches.fieldexplorationofthesiteshallbemadetodetermineifthereissurfacesoilofsufficientquantityandqualitytojustifystripping.Topsoilshallbefriableandloamy(loam,sandyloam,siltloam,sandyclayloam,andclayloam).Avoidareasofnaturalgroundwaterrecharge.Strippingshallbeconfinedtotheimmediateconstructionarea.A4-inchto6-inchstrippingdepthiscommon,butdepthmayvarydependingontheparticularsoil.Allsurfacerunoffcontrolstructuresshallbeinplacepriortostripping.Donotplacetopsoilwhileinafrozenormuddycondition,whenthesubgradeisexcessivelywet,orwhenconditionsexistthatmayotherwisebedetrimentaltopropergradingorproposedsoddingorseeding.Inanyareasrequiringgradingremoveandstockpilethedufflayerandtopsoilonsiteinadesignated,controlledarea,notadjacenttopublicresourcesandcriticalareas.Stockpiledtopsoilistobereappliedtootherportionsofthesitewherefeasible.Locatethetopsoilstockpilesothatitmeetsspecificationsanddoesnotinterferewithworkonthesite.Itmaybepossibletolocatemorethanonepileinproximitytoareaswheretopsoilwillbeused.Stockpilingoftopsoilshalloccurinthefollowingmanner:.Sideslopesofthestockpileshallnotexceed2H:1V..BetweenOctober1andApril30:.Aninterceptordikewithgraveloutletandsiltfenceshallsurroundalltopsoil..Within2dayscompleteerosioncontrolseeding,orcoveringstockpileswithclearplastic,orothermulchingmaterials..BetweenMay1andSeptember30:IAninterceptordikewithgraveloutletandsiltfenceshallsurroundalltopsoilifthestockpilewillremaininplaceforalongerperiodoftimethanactiveconstructiongrading..Within7dayscompleteerosioncontrolseeding,orcoveringstockpileswithclearplastic,orothermulchingmaterials.Whennativetopsoilistobestockpiledandreusedthefollowingshouldapplytoensurethatthemycorrhizalbacterial,earthworms,andotherbeneficialorganismswillnotbedestroyed:1.Re-installtopsoilwithin4to6weeks.olumeConstructionStormwaterPollutionPreentionuust20121 2.Donotallowthesaturationoftopsoilwithwater.3.Donotuseplasticcovering.Mainte;ic,izce•Inspectstockpilesregularly,especiallyafterlargestormevents.StandardsStabilizeanyareasthathaveeroded.•Establishsoilqualityanddepthtowardtheendofconstructionandonceestablished,protectfromcompaction,suchasfromlargemachineryuse,andfromerosion.•Plantandmulchsoilafterinstallation.•Leaveplantdebrisoritsequivalentonthesoilsurfacetoreplenishorganicmatter.•Reduceandadjust,wherepossible,theuseofirrigation,fertilizers,herbicidesandpesticides,ratherthancontinuingtoimplementformerlyestablishedpractices.BMPC126:Polyacrylamide(PAM)forSoilErosionProtectionPuiposePolyacrylamide(PAM)isusedonconstructionsitestopreventsoilerosion.ApplyingPAMtobaresoilinadvanceofaraineventsignificantlyreduceserosionandcontrolssedimentintwoways.first,PAMincreasesthesoil’savailableporevolume,thusincreasinginfiltrationthroughflocculationandreducingthequantityofstormwaterrunoff.Second,itincreasesflocculationofsuspendedparticlesandaidsintheirdeposition,thusreducingstonrnvaterrunoffturbidityandimprovingwaterquality.ConditionsofUsePAMshallnotbedirectlyappliedtowaterorallowedtoenterawaterbody.Inareasthatdraintoasedimentpond,PAMcanbeappliedtobaresoilunderthefollowingconditions:•Duringroughgradingoperations.•InStagingareas.•Balancedcutandfillearthwork.•Haulroadspriortoplacementofcrushedrocksurfacing.•Compactedsoilroadbase.•Stockpiles.•Afterfinalgradeandbeforepavingorfinalseedingandplanting.•Pitsites.olumeConstructionStormwaterPollutionPreentionuust20122 .Siteshavingawintershutdown.inthecaseofwintershutdown.orwheresoilwillremainunworkedforseveralmonths,PAMshouldbeusedtogetherwithmulch.PAMmaybeapplied‘ithwaterindissolvedform.ThepreferredDesiai;tii;d.applicationmethodisthedissolvedform.InstctllatwiiSpecificationsPAMistobeappliedatamaximumrateof2/3poundPAMper1,000gallonswater(80rng/L)per1acreofbaresoil.Table4.1.9canbeusedtodeterminethePAMandwaterapplicationrateforadisturbedsoilarea.HigherconcentrationsofPAMdonoprovideanyadditionaleffectiveness.Table4.1.9PAMandWaterApplicationRatesDirdAra(a)PAM()War(a)0.500.335001.000.661,0001.501.001,5002.001.322,0002.501.652,5003.002.003,0003.502.333,5004.002.654,0004.503.004,500-5.003.335,000ThePreferredMethod:.Pre-measuretheareawherePAMistobeappliedandcalculatetheamountofproductandwaternecessarytoprovidecoverageatthespecifiedapplicationrate(2/3poundPAMI1000gallons/acre)..PAMhasinfinitesolubilityinwater,butdissolvesveryslowly.Dissolvepre-measureddrygranularPAMwithaknownquantityofcleanwaterinabucketseveralhoursorovernight.MechanicalmixingwillhelpdissolvethePAM.AlwaysaddPAMtowater-notwatertoPAM..Pre-fillthewatertruckabout1/8fullwithwater.Thewaterdoesnothavetobepotable,butitmusthaverelativelylowturbidity—intherangeof2ONTUorless..AddPAM/Watermixturetothetruck.Completelyfillthewatertrucktospecifiedvolume..SprayPAM/Watermixtureontodrysoiluntilthesoilsurfaceisuniformlyandcompletelywetted.AnAlternateMethod:olitmeConstructionStornm’aterPollutionPreentionuust2012 PAMmayalsobeappliedasapowderattherateof5lbs.peracre.Thismustbeappliedonadaythatisdry.forareaslessthan5-10acres,ahand-held“organgrinder”fertilizerspreadersettothesmallestsettingwillwork.Tractor-mountedspreaderswillworkforlargerareas.ThefollowingshallbeusedforapplicationofpowderedPAM:.PoweredPAMshallbeusedinconjunctionwithotherBMPsandnotinplaceofotherBMPs..DonotusePAMonaslopethatflowsdirectlyintoastreamorwetland.ThestorrnwaterrunoffshallpassthroughasedimentcontrolBMPpriortodischargingtosurfacewaters..DonotaddPAMtowaterdischargingfromsite..Whenthetotaldrainageareaisgreaterthanorequalto5acres,PAMtreatedareasshalldraintoasedimentpond..Areaslessthan5acresshalldraintosedimentcontrolBMPs,suchasaminimumof3checkdamsperacre.Thetotalnumberofcheckdamsusedshallbemaximizedtoachievethegreatestamountofsettlementofsedimentpriortodischargingfromthesite.Eachcheckdamshallbespacedevenlyinthedrainagechamelthroughwhichstormwaterflowsaredischargedoff-site..Onallsites,theuseofsiltfenceshallbemaximizedtolimitthedischargesofsedimentfromthesite..Allareasnotbeingactivelyworkedshallbecoveredandprotectedfromrainfall.PAMshallnotbetheonlycoverBMPused..PAMcanbeappliedtowetsoil,butdrysoilispreferredduetolesssedimentloss..PAMwillworkwhenappliedtosaturatedsoilbutisnotaseffectiveasapplicationstodryordampsoil..KeepthegranularPAMsupplyoutofthesun.GranularPAMlosesitseffectivenessinthreemonthsafterexposuretosunlightandair..Properapplicationandre-applicationplansarenecessarytoensuretotaleffectivenessofPAMusage..PAM,combinedwithwater,isveryslipperyandcanbeasafetyhazard.CaremustbetakentopreventspillsofPAMpowderontopavedsurfaces.DuringanapplicationofPAM,preventover-sprayfromreachingpavementaspavementwillbecomeslippery.IfPAMpowdergetsonskinorclothing,wipeitoffwitharoughtowelratherthanwashingwithwater-thisonlymakescleanupmessierandtakelonger..SomePAMsaremoretoxicandcarcinogenicthanothers.OnlythemostenvironmentallysafePAMproductsshouldbeused.olitmeConstructionStorrnwaterPollutionPreentionuust2012 ThespecificPAMcopolyrnerformulationmustbeanionic.CaioniPA11anodinanaIaionaofnonaaI01110.OnlythehighestdrinkingwatergradePAM,certifiedforcompliancewithANSI/NSFStandard60fordrinkingwatertreatment.willbeusedforsoilapplications.RecentmediaattentionandhighinterestinPAMhasresultedinsomeentrepreneurialexploitationoftheterm“polymer.’AllPAMarepolymers,butnotallpolymersarePAM,andnotallPAMproductscomplywithANSi/NSFStandard60.PAMuseshallbereviewedandapprovedbythelocalpermittingauthority..PAMdesignatedfortheseusesshouldbe“watersoluble”or“linear”or“nomcrosslinked”.Cross-linkedorwaterabsorbentPAM,polymerizedinhighlyacidic(pH<2)conditions,areusedtomaintainsoilmoisturecontent..ThePAManionicchargedensitymayvaryfrom2-30percent;avalueof18percentistypical.StudiesconductedbytheUnitedStatesDepartmentofAgriculture(USDA)/ARSdemonstratedthatsoilstabilizationwasoptimizedbyusingveryhighmolecularweight(12-15mg/mole),highlyanionic(>20%hydrolysis)PAM.PAMtackifiersareavailableandbeingusedinplaceofguarandalphaplantago.Typically,PAMtackifiersshouldbeusedatarateofnomorethan0.5-1lb.per1000gallonsofwaterinahydrornuichmachine.Sometackifierproductinstructionssaytouseatarateof3—5lbs.peracre,whichcanbetoomuch.Inaddition,pumpproblemscanoccurathigherratesduetoincreasedviscosity.Maintena,;ce•PAMmaybereappliedonactivelyworkedareasaftera4$-hourStandardsperiod.•ReapplicationisnotrequiredunlessPAMtreatedsoilisdisturbedorunlessturbiditylevelsshowtheneedforanadditionalapplication.IfPAMtreatedsoilisleftundisturbedareapplicationmaybenecessaryaftertwomonths.MorePAMapplicationsmayberequiredforsteepslopes,siltyandclayeysoils(USDAClassificationType“C”and“D”soils),longgrades,andhighprecipitationareas.WhenPAMisappliedfirsttobaresoilandthencoveredwithstraw,areapplicationmaynotbenecessaryforseveralmonths.•LossofsedimentandPAMmaybeabasisforpenaltiesperRCW90.48.080.BMPC130:SurfaceRougheningPurposeSurfacerougheningaidsintheestablishmentofvegetativecover,reducesrunoffvelocity,increasesinfiltration,andprovidesforsedimenttrappingthroughtheprovisionofaroughsoilsurface.HorizontaldepressionsareolumeConstructionStormwaterPollutionPreentionuust2012 createdbyoperatingatillerorothersuitableequipmentonthecontourorbyleavingslopesinaroughenedconditionbynotfinegradingthem.UsethisBMPinconjunctionwithotherBMPssuchasseeding,mulching,orsodding.Coiiditionsfor.Allslopessteeperthan3H:1Vandgreaterthan5verticalfeetUserequiresurfacerougheningtoadepthof2to4inchespriortoseeding...Areasthatwillnotbestabilizedimmediatelymayberoughenedtoreducerunoffvelocityuntilseedingtakesplace..Slopeswithastablerockfacedonotrequireroughening..Slopeswheremowingisplannedshouldnotbeexcessivelyroughened.Desigi;andTherearedifferentmethodsforachievingaroughenedsoilsurfaceonaInstallationslope,andtheselectionofanappropriatemethoddependsuponthetypeofSpecificationsslope.Rougheningmethodsincludestair-stepgrading,grooving,contourfulTOws,andtracking.Seefigure4.1.5fortrackingandcontourfurrows.Factorstobeconsideredinchoosingamethodareslopesteepness,mowingrequirements,andwhethertheslopeisformedbycuttingorfilling..Disturbedareasthatwillnotrequiremowingmaybestair-stepgraded,grooved,orleftroughafterfilling..Stair-stepgradingisparticularlyappropriateinsoilscontaininglargeamountsofsoftrock.Each“step”catchesmaterialthatsloughsfromabove,andprovidesalevelsitewherevegetationcanbecomeestablished.Stairsshouldbewideenoughtoworkwithstandardearthmovingequipment.Stairstepsmustbeoncontourorgullieswillformontheslope..Areasthatwillbemowed(theseareasshouldhaveslopeslesssteepthan3H:1V)mayhavesmallfurrowsleftbydisking,harrowing,raking,orseed-plantingmachineryoperatedonthecontour..Gradedareaswithslopessteeperthan3H:1Vbutlessthan2H:1Vshouldberoughenedbeforeseeding.Thiscanbeaccomplishedinavarietyofways,including“trackwalking,”ordrivingacrawlertractorupanddowntheslope,leavingapatternofcleatimprintsparalleltoslopecontours..Trackingisdonebyoperatingequipmentupanddowntheslopetoleavehorizontaldepressionsinthesoil.Maintenance•AreasthataregradedinthismannershouldbeseededasquicklyasStandardspossible.•Regularinspectionsshouldbemadeofthearea.Ifrillsappear,theyshouldbere-gradedandre-seededimmediately.oluineConstructionStornnraterPollutionPreentionuust2012 Tracking--EE—-_---:-:E-Ez__-—Z____N::----N=—:-=--1__‘z,----—=E_--——.-;-_ContourFurrows‘TRACKING’withmachineryupanddowntheslopeprovidesgroovesthatwillcatchseed,rainfallandreducerunoff./S50’/(15m//(150mm)MaidmumyGroovesWillCatchSeed,Fertilizer,Mulch,RainfallandDecreaseRunoff.Figure4.1.5—SurfaceRougheningbyTrackingandContourFurrowsolumeConstructionStormwaterPollutionPreentionitust2012 BMPCl31:GradientTerracesPuiposeGradientterracesreduceerosiondamagebyinterceptingsurfacerunoffandconductingittoastableoutletatanon-erosivevelocity.ConditionsofUse.GradienttelTacesnormallyarelimitedtodenudedlandhavingawatererosionproblem.Theyshouldnotbeconstructedondeepsandsoronsoilsthataretoostony,steep,orshallowtopermitpracticalandeconomicalinstallationandmaintenance.Gradientterracesmaybeusedonlywheresuitableoutletsareorwillbemadeavailable.SeeFigure4.1.6forgradientterraces.Designand•ThemaximumverticalspacingofgradientterracesshouldbeInstallationdeterminedbythefollowingmethod:SpecificationsVI=(O.$)s+yWhere:VIverticalintervalinfeetS=landriseper100feet,expressedinfeety=asoilandcovervariablewithvaluesfrom1.0to4.0Valuesof“y”areinfluencedbysoilerodibilityandcoverpractices.Thelowervaluesareapplicabletoerosivesoilswherelittletonoresidueisleftonthesurface.Thehighervalueisapplicableonlytoerosion-resistantsoilswherealargeamountofresidue(1V2tonsofstraw/acreequivalent)isonthesurface.•Theminimumconstructedcross-sectionshouldmeetthedesigndimensions.•Thetopoftheconstructedridgeshouldnotbeloweratanypointthanthedesignelevationplusthespecifiedoverfillforsettlement.Theopeningattheoutletendoftheterraceshouldhaveacrosssectionequaltothatspecifiedfortheterracechannel.•Channelgradesmaybeeitheruniformorvariablewithamaximumgradeof0.6feetper100feetlength(0.6%).Forshortdistances,terracegradesmaybeincreasedtoimprovealignment.Thechannelvelocityshouldnotexceedthatwhichisnonerosiveforthesoiltype.•Allgradientterracesshouldhaveadequateoutlets.Suchanoutletmaybeagrassedwaterway,vegetatedarea,ortileoutlet.Inallcasestheoutletmustconveyrunofffromtheterraceorterracesystemtoapointwheretheoutflowwillnotcausedamage.Vegetativecovershouldbeusedintheoutletchannel.•Thedesignelevationofthewatersurfaceoftheterraceshouldnotbelowerthanthedesignelevationofthewatersurfaceintheoutletattheirjunction,whenbothareoperatingatdesignflow.olumeConstructionStol7llwaterPollutionPreentionuust2012 .Verticalspacingdeterminedbytheabovemethodsmaybeincreasedasmuchas0.5feetor10percent,whicheverisgreater,toprovidebetteralignmentorlocation,toavoidobstacles,toadjustforequipmentsize,ortoreachasatisfactoryoutlet.Thedrainageareaabovetheterraceshouldnotexceedtheareathatwouldbedrainedbyaterracewithnormalspacing..Theterraceshouldhaveenoughcapacitytohandlethepeakrunoffexpectedfroma2-year,24-hourdesignstormwithoutovertopping..Thetenacecross-sectionshouldbeproportionedtofitthelandslope.Theridgeheightshouldincludeareasonablesettlementfactor.Theridgeshouldhaveaminimumtopwidthof3feetatthedesignheight.Themininmmcross-sectionalareaoftheterracechannelshouldbe8squarefeetforlandslopesof5percentorless,7squarefeetforslopesfrom5to8percent,and6squarefeetforslopessteeperthan8percent.Theterracecanbeconstructedwideenoughtobemaintainedusingasmallvehicle.Mainteizance•Maintenanceshouldbeperformedasneeded.TerracesshouldbeStandardsinspectedregularly;atleastonceayear,andafterlargestormevents.Slopetoadequate—_-—-—Figure4.1.6—GradientTerracesolitmeConstructionStor,m%’aterPollutionPreentionuust2012 BMPC140:DustControlPuiposeDustcontrolpreventswindtransportofdustfromdisturbedsoilsurfacesontoroadways,drainageways,andsurfacewaters.Conditioi;sofUse•Inareas(includingroadways)subjecttosurfaceandairmovementofdustwhereon-siteandoff-siteimpactstoroadways,drainageways,orsurfacewatersarelikely.Designand•Vegetateormulchareasthatwillnotreceivevehicletraffic.InareasInstallationwhereplanting,mulching,orpavingisimpractical,applygravelorSpecificationslandscapingrock.•Limitdustgenerationbyclearingonlythoseareaswhereimmediateactivitywilltakeplace,leavingtheremainingarea(s)intheoriginalcondition.Maintaintheoriginalgroundcoveraslongaspractical.•Constructnaturalorartificialwindbreaksorwindscreens.Thesemaybedesignedasenclosuresforsmalldustsources.•Sprinklethesitewithwateruntilsurfaceiswet.Repeatasneeded.Topreventcarryoutofmudontostreet,refertoStabilizedConstructionEntrance(BMPC105).•Irrigationwatercanbeusedfordustcontrol.Irrigationsystemsshouldbeinstalledasafirststeponsiteswheredustcontrolisaconcern.•Sprayexposedsoilareaswithadustpalliative,followingthemanufacturer’sinstructionsandcautionsregardinghandlingandapplication.Usedoilisprohibitedfromuseasadustsuppressant.LocalgovernmentsmayapproveotherdustpalliativessuchascalciumchlorideorPAM.•PAM(BMPC126)addedtowateratarateof0.5lbs.per1,000gallonsofwaterperacreandappliedfromawatertruckismoreeffectivethanwateralone.Thisisduetoincreasedinfiltrationofwaterintothesoilandreducedevaporation.Inaddition,smallsoilparticlesarebondedtogetherandarenotaseasilytransportedbywind.AddingPAMmayactuallyreducethequantityofwaterneededfordustcontrol.UseofPAMcouldbeacost-effectivedustcontrolmethod.Techniquesthatcanbeusedforunpavedroadsandlotsinclude:•Lowerspeedlimits.Highvehiclespeedincreasestheamountofduststirredupfromunpavedroadsandlots.•Upgradetheroadsurfacestrengthbyimprovingparticlesize,shape,andmineraltypesthatmakeupthesurfaceandbasematerials.•Addsurfacegraveltoreducethesourceofdustemission.Limittheamountoffineparticles(thosesmallerthan.075mm)to10to20percent.olumeConstructionStormwaterPollutionPreentionuust20120 .Usegeotextilefabricstoincreasethestrengthofnewroadsorroadsundergoingreconstruction..Encouragetheuseofalternate,pavedroutes,ifavailable..Restrictuseofpavedroadwaysbytrackedvehiclesandheavytruckstopreventdamagetoroadsurfaceandbase..Applychemicaldustsuppressantsusingtheadmixmethod,blendingtheproductwiththetopfewinchesofsurfacematerial.Suppressantsmayalsobeappliedassurfacetreatments..Paveunpavedpermanentroadsandothertraffickedareas..Usevacuumstreetsweepers..Removemudandotherdirtpromptlysoitdoesnotdryandthenturnintodust..Limitdust-causingworkonwindydays..ContactyourlocalAirPollutionControlAuthorityforguidanceandtrainingonotherdustcontrolmeasures.CompliancewiththelocalAirPollutionControlAuthorityconstitutescompliancewiththisBMP.MaintenanceResprayareaasnecessarytokeepdusttoaminimum.Standards.BMPC150:MaterialsonHandPuiposeKeepquantitiesoferosionpreventionandsedimentcontrolmaterialsontheprojectsiteatalltimestobeusedforregularmaintenanceandemergencysituationssuchasunexpectedheavysummerrains.Havingthesematerialson-sitereducesthetimeneededtoimplementBMPswheninspectionsindicatethatexistingBMPsarenotmeetingtheConstructionSwPPPrequirements.Inaddition,contractorscansavemoneybybuyingsomematerialsinbulkandstoringthemattheirofficeoryard.ConditionsofUse•Constructionprojectsofanysizeortypecanbenefitfromhavingmaterialsonhand.Asmallcommercialdevelopmentprojectcouldhavearollofplasticandsomegravelavailableforimmediateprotectionofbaresoilandtemporarybermconstruction.Alargeearthworkproject,suchashighwayconstruction,mighthaveseveraltonsofstraw,severalrollsofplastic,flexiblepipe,sandbags,geotextilefabricandsteel“I”posts.•Materialsarestockpiledandreadilyavailablebeforeanysiteclearing,grubbing,orearthworkbegins.Alargecontractorordevelopercouldkeepastockpileofmaterialsthatareavailableforuseonseveralprojects.•Ifstoragespaceattheprojectsiteisatapremium,thecontractorcouldmaintainthematerialsattheirofficeoryard.Theofficeoryardmustbelessthananhourfromtheprojectsite.oluineConstructionStormwaterPollutionPreentionitust2012I DesignaiidDependingonprojecttype,size.complexity.andlength,materialsandI,istctllationquantitieswillvary.AgoodminimumlistofitemsthatwillcoverSpecxjicatioiisnumeroussituationsincludes:MaterialClearPlastic,6ml!______ ____Drainpipe,6or8inchdiameterSandbags,filledStrawBalesfornmlching,WashedGravel_____________GeotextileFabric___________CatchBasinInserts_____________Steel “I”Posts ___________ _______ ____Siltfencematerial__________________StrawWattlesMabzteiiaiice•Allmaterialswiththeexceptionofthequarryspalls,steel“T”posts,Staiidardsandgravelshouldbekeptcoveredandoutofbothsunandrain.•Re-stockmaterialsusedasneeded.BMPC151:ConcreteHandlingPuiposeConcreteworkcangenerateprocesswaterandslurrythatcontainfineparticlesandhighpH,bothofwhichcanviolatewaterqualitystandardsinthereceivingwater.ConcretespillageorconcretedischargetosurfacewatersoftheStateisprohibited.UsethisBMPtominimizeandeliminateconcrete,concreteprocesswater,andconcreteslurryfromenteringwatersofthestate.Coi;ditionsofUseAnytimeconcreteisused,utilizethesemanagementpractices.Concreteconstructionprojectsinclude,butarenotlimitedto,thefollowing:•Curbs•Sidewalks•Roads•Bridges•Foundations•Floors•RunwaysDesignand•Washoutconcretetruckchutes,pumps,andinternalsintoformedInstallationareasonly.Assurethatwashoutofconcretetrucksisperformedoff-olumeConstructionStorniwaterPollutionPreentioniiust20122 Specificationssiteorindesignatedconcretewashoutareas.Donotwashoutconcretetrucksontotheground.orintostormdrains.openditches.streets,orstreams.RefertoBMPC154forinformationonconcretewashoutareas..Returnunusedconcreteremaininginthetruckandpumptotheoriginatingbatchplantforrecycling.Donotdumpexcessconcreteonsite,exceptindesignatedconcretewashoutareas..Washoffhandtoolsincluding,butnotlimitedto,screeds,shovels,rakes,floats,andtrowelsintoformedareasoniy..Washequipmentdifficulttomove,suchasconcretepayersinareasthatdonotdirectlydraintonaturalorconstructedstorrnwaterconveyances..Donotallowwashdownfromareas,suchasconcreteaggregatedriveways,todraindirectlytonaturalorconstructedstormwaterconveyances..Containwashwaterandleftoverproductinalinedcontainerwhennoformedareasareavailable,.Disposeofcontainedconcreteinamannerthatdoesnotviolategroundwaterorsurfacewaterqualitystandards..Alwaysuseformsorsolidbaniersforconcretepours,suchaspilings,within15-feetofsurfacewaters..RefertoBMPsC252andC253forpHadjustmentrequirements..RefertotheConstructionStormwaterGeneralPermitforpHmonitoringrequirementsiftheprojectinvolvesoneofthefollowingactivities:.Significantconcretework(greaterthan1,000cubicyardspouredconcreteorrecycledconcreteusedoverthelifeofaproject)..Theuseofengineeredsoilsamendedwith(butnotlimitedto)Portlandcement-treatedbase,cementkilndustorflyash..Dischargingstormwatertosegmentsofwaterbodiesonthe303(d)list(Category5)forhighpH.MaintenanceCheckcontainersforholesinthelinerdailyduringconcretepoursandStandardsrepairthesameday.ohimeConstructionStonnwaterPollutionPreentionuust2012 BMPC152:SawcuttingandSurfacingPollutionPreventionPuiposeSawcuttingandsurfacingOpCfatiOflSgenerateslurryandprocesswaterthatcontainsfineparticlesandhighpH(concretecutting),bothofwhichcanviolatethewaterqualitystandardsinthereceivingwater.Concrete.spillageorconcretedischargetosurfacewatersoftheStateisprohibited.UsethisBMPtominimizeandeliminateprocesswaterandslurrycreatedthroughsawcuttingorsurfacingfromenteringwatersoftheState.ConditionsofUseUtilizethesemanagementpracticesanytimesawcuttingorsurfacingoperationstakeplace.Sawcuttingandsurfacingoperationsinclude,butarenotlimitedto,thefollowing:.Sawing.Coring.Grinding.Roughening.Hydro-demolition.BridgeandroadsurfacingDesigna;id•Vacuumslurryandcuttingsduringcuttingandsurfacingoperations.histailatlo,,.•SlurryandcuttingsshallnotremainonpermanentconcreteorasphaltSpecificationspavementovernight.•Slurryandcuttingsshallnotdraintoanynaturalorconstructeddrainageconveyanceincludingstorrnwatersystems.Thismayrequiretemporarilyblockingcatchbasins.•Disposeofcollectedslurryandcuttingsinamannerthatdoesnotviolategroundwaterorsurfacewaterqualitystandards.•Donotallowprocesswatergeneratedduringhydro-demolition,surfacerougheningorsimilaroperationstodraintoanynaturalorconstructeddrainageconveyanceincludingstorrnwatersystems.Disposeprocesswaterinamannerthatdoesnotviolategroundwaterorsurfacewaterqualitystandards.•Handleanddisposecleaningwastematerialanddemolitiondebrisinan;annerthatdoesnotcausecontaminationofwater.Disposeofsweepingmaterialfromapick-upsweeperatanappropriatedisposalsite.Mainte;;anceContinuallymonitoroperationstodeterminewhetherslurry,cuttings,orStandardsprocesswatercouldenterwatersofthestate.Ifinspectionsshowthataviolationofwaterqualitystandardscouldoccur,stopoperationsandimmediatelyimplementpreventivemeasuressuchasberms,barriers,secondarycontainment,andvacuumtrucks.olumeConstructionStormwaterPollutionPreentionuust2012 BMPC153:MaterialDelivery,StorageandContainmentPurposePrevent,reduce,oreliminatethedischargeofpollutantstothestormwatersystemorwatercoursesfrommaterialdeliveryandstorage.Minimizethestorageofhazardousmaterialson-site,storematerialsinadesignatedarea,andinstallsecondarycontainment.Co;tdllionsofUseTrodrarIaforaaonrioniidIrandoraoffooinana.Petroleumproductssuchasfuel,oilandgrease.Soilstabilizersandbinders(e.g.Polyacrylamide).fertilizers,pesticidesandherbicides.Detergents.Asphaltandconcretecompounds.Hazardouschemicalssuchasacids,lime,adhesives,paints,solventsandcuringcompounds.AnyothermaterialthatmaybedetrimentalifreleasedtotheenvironmentDesigi;andTfooinodaiiomlIniInstallation•Temporarystorageareashouldbelocatedawayfromvehiculartraffic,Spec;ficatioitsneartheconstructionentrance(s),andawayfromwaterwaysorstormdrains.•MaterialSafetyDataSheets(MSDS)shouldbesuppliedforallmaterialsstored.Chemicalsshouldbekeptintheiroriginallabeledcontainers.•Hazardousmaterialstorageon-siteshouldbeminimized.•Hazardousmaterialsshouldbehandledasinfrequentlyaspossible.•Duringthewetweatherseason(Oct1—April30),considerstoringmaterialsinacoveredarea.•Materialsshouldbestoredinsecondarycontainments,suchasearthendike,horsetrough,orevenachildren’swadingpooifornon-reactivematerialssuchasdetergents,oil,grease,andpaints.Smallamountsofmaterialmaybesecondarilycontainedin“busboy”traysorconcretemixingtrays.•Donotstorechemicals,drums,orbaggedmaterialsdirectlyontheground.Placetheseitemsonapalletand,whenpossible,andwithinsecondarycontainment.•Ifdrumsmustbekeptuncovered,storethemataslightangletoreducepondingofrainwateronthelidstoreducecorrosion.Domedplasticcoversareinexpensiveandsnaptothetopofdrums,preventingwaterfromcollecting.ohtmeConstructionStorrnwaterPollutionPreentionuust2012 ManaSoraAraandSondarConamnPraI.Liquids,petroleumproducts,andsubstanceslistedin40CFRParts110.117or302shallbestoredinapprovedcontainersanddrumsandshallnotbeoverfihled.Containersanddrumsshallbestoredintemporarysecondarycontainmentfacilities..Temporarysecondarycontainmentfacilitiesshallprovideforaspillcontainmentvolumeabletocontain10%ofthetotalenclosedcontainervolumeofallcontainers,or110%ofthecapacityofthelargestcontainerwithinitsboundary,whicheverisgreater..Secondarycontainmentfacilitiesshallbeimpervioustothematerialsstoredthereinforaminimumcontacttimeof72hours..Secondarycontainmentfacilitiesshallbemaintainedfreeofaccumulatedrainwaterandspills.Intheeventofspillsorleaks,accumulatedrainwaterandspillsshallbecollectedandplacedintodrums.Theseliquidsshallbehandledashazardouswasteunlesstestingdeterminesthemtobenon-hazardous..Sufficientseparationshouldbeprovidedbetweenstoredcontainerstoallowforspillcleanupandemergencyresponseaccess..Duringthewetweatherseason(Oct1—April30),eachsecondarycontainmentfacilityshallbecoveredduringnon-workingdays,priortoandduringrainevents..Keepmaterialstorageareasclean,organizedandequippedwithanamplesupplyofappropriatespillclean-upmaterial(spillkit)..Thespillkitshouldinclude,ataminimum:.1-WaterResistantNylonBag.3-OilAbsorbentSocks3”x4’.2-OilAbsorbentSocks3”x10’I12-OilAbsorbentPads17”x19”.1-PairSplashResistantGoggles.3-PairNitrileGloves.10-DisposableBagswithTies.InstructionsohimeConstructionStornn4’aterPollutionFreentionuust2012 BMPC154:ConcreteWashoutAreaPuiposePreventorreducethedischargeofpollutantstostormwaterfromconcretewastebyconductingwashoutoff-site,orperformingon-sitewashoutinadesignatedareatopreventpollutantsfromenteringsurfacewatersorgroundwater.ConditionsofUseConcretewashoutareabestmanagementpracticesareimplementedonconstructionprojectswhere:.Concreteisusedasaconstructionmaterial.Itisnotpossibletodisposeofallconcretewastewaterandwashoutoff-site(readymixplant,etc.)..Concretetrucks,pumpers,orotherconcretecoatedequipmentarewashedon-site..Note:Iflessthan10concretetrucksorpumpersneedtobewashedouton-site,thewashwatermaybedisposedofinaformedareaawaitingconcreteoranuplanddisposalsitewhereitwillnotcontaminatesurfaceorgroundwater.Theuplanddisposalsiteshallbeatleast50feetfromsensitiveareassuchasstormdrains,openditches,orwaterbodies,includingwetlands.DesignandIiiaionInstallation..ThefollowingstepswillhelpreducestorrnwaterpollutionfromconcreteSpecificationswastes:.Performwashoutofconcretetrucksoff-siteorindesignatedconcretewashoutareasoniy..Donotwashoutconcretetrucksontotheground,orintostormdrains,openditches,streets,orstreams..Donotallowexcessconcretetobedumpedon-site,exceptindesignatedconcretewashoutareas..Concretewashoutareasmaybeprefabricatedconcretewashoutcontainers,orself-installedstructures(above-gradeorbelow-grade)..Prefabricatedcontainersaremostresistanttodamageandprotectagainstspillsandleaks.Companiesmayofferdeliveryserviceandprovideregularmaintenanceanddisposalofsolidandliquidwaste..Ifself-installedconcretewashoutareasareused,below-gradestructuresarepreferredoverabove-gradestructuresbecausetheyarelesspronetospillsandleaks..Self-installedabove-gradestructuresshouldonlybeusedifexcavationisnotpractical.oltimeConstructionStorrnwaterPollutionPreentionuust2012 Edaion.DiscusstheconcretemanagementtechniquesdescribedinthisBMPwiththeready-mixconcretesupplierbeforeanydeliveriesaremade..EducateemployeesandsubcontractorsontheconcretewastemanagementtecimiquesdescribedinthisBMP..Arrangeforcontractor’ssuperintendentorCertifiedErosionandSedimentControlLead(CESCL)tooverseeandenforceconcretewastemanagementprocedures..Asignshouldbeinstalledadjacenttoeachtemporaryconcretewashoutfacilitytoinformconcreteequipmentoperatorstoutilizetheproperfacilities.ConraIncorporaterequirementsforconcretewastemanagementintoconcretesupplierandsubcontractoragreements.LoaionandPaH.Locatewashoutareaatleast50feetfromsensitiveareassuchasstormdrains,openditches,orwaterbodies,includingwetlands..Allowconvenientaccessforconcretetrucks,preferablyneartheareawheretheconcreteisbeingpoured..Iftrucksneedtoleaveapavedareatoaccesswashout,preventtrack-outwithapadofrockorquarryspalls(seeBMPC105).Theseareasshouldbefarenoughawayfromotherconstructiontraffictoreducethelikelihoodofaccidentaldamageandspills..Thenumberoffacilitiesyouinstallshoulddependontheexpecteddemandforstoragecapacity..Onlargesiteswithextensiveconcretework,washoutsshouldbeplacedinmultiplelocationsforeaseofusebyconcretetruckdrivers.On-iTorarConrWaofaii,TraniTrWaoProdr.Temporaryconcretewashoutfacilitiesshallbelocatedaminimumof50ftfromsensitiveareasincludingstormdraininlets,opendrainagefacilities,andwatercourses.SeeFigures4.1.7and4.1.8..Concretewashoutfacilitiesshallbeconstructedandmaintainedinsufficientquantityandsizetocontainallliquidandconcretewastegeneratedbywashoutoperations..Approximately7gallonsofwashwaterareusedtowashonetruckchute..Approximately50gallonsareusedtowashoutthehopperofaconcretepumptruck.olumeConstructionStorinwaterPollutionPreentionuust20]2 Washoutofconcretetrucksshallbeperformedindesignatedareasonly.Concretewashoutfromconcretepumperbinscanbewashedintoconcretepumpertrucksanddischargedintodesignatedwashoutareaorproperlydisposedofoff-site.Onceconcretewastesarewashedintothedesignatedareaandallowedtoharden,theconcreteshouldbebrokenup,removed,anddisposedofperapplicablesolidwasteregulations.Disposeofhardenedconcreteonaregularbasis.TemporaryAbove-GradeConcreteWashoutFacility.Temporaryconcretewashoutfacility(typeabovegrade)shouldbeconstructedasshownonthedetailsbelow,witharecommendedminimumlengthandminimumwidthof10ft,butwithsufficientquantityandvolumetocontainallliquidandconcretewastegeneratedbywashoutoperations..Plasticliningmaterialshouldbeaminimumof10mupolyethylenesheetingandshouldbefreeofholes,tears,orotherdefectsthatcompromisetheimpermeabilityofthematerial.TemporaryBelow-GradeConcreteWashoutFacility.Temporaryconcretewashoutfacilities(typebelowgrade)shouldbeconstructedashownonthedetailsbelow,witharecommendedminimumlengthandminimumwidthof10ft.Thequantityandvolumeshouldbesufficienttocontainallliquidandconcretewastegeneratedbywashoutoperations..Lathandflaggingshouldbecommercialtype..Plasticliningmaterialshallbeaminimumof10mupolyethylenesheetingandshouldbefreeofholes,tears,orotherdefectsthatcompromisetheimpermeabilityofthematerial.aLinerseamsshallbeinstalledinaccordancewithmanufacturers’recommendations.SSoilbaseshallbepreparedfreeofrocksorotherdebristhatmaycausetearsorholesintheplasticliningmaterial.Mai;ttenanceInionandMainnanStandardsaInspectandverifythatconcretewashoutBMPsareinplacepriortothecommencementofconcretework.aDuringperiodsofconcretework,inspectdailytoverifycontinuedperformance..Checkoverallconditionandperformance..Checkremainingcapacity(%full).olumeConstructionStormvaterPollutionPreentionuust2012 .Ifusingself-installedwashoutfacilities.verifyplasticlinersareintactandsidewallsarenotdamaged..Ifusingprefabricatedcontainers,checkforleaks..Washoutfacilitiesshallbemaintainedtoprovideadequateholdingcapacitywithaminimumfreeboardof12inches..Washoutfacilitiesmustbecleaned.ornewfacilitiesmustbeconstructedandreadyforuseoncethewashoutis75%full..Ifthewashoutisnearingcapacity.vacuumanddisposeofthewastematerialinanapprovedmanner..Donotdischargeliquidorslurrytowaterways,stormdrainsordirectlyontoground..Donotusesanitarysewerwithoutlocalapproval..Placeasecure,non-collapsing,non-watercollectingcoverovertheconcretewashoutfacilitypriortopredictedwetweathertopreventaccumulationandoverflowofprecipitation..Removeanddisposeofhardenedconcreteandreturnthestructuretoafunctionalcondition.Concretemaybereusedon-siteorhauledawayfordisposalorrecycling..Whenyouremovematerialsfromtheself-installedconcretewashout,buildanewstructure;or,ifthepreviousstructureisstillintact,inspectforsignsofweakeningordamage,andmakeanynecessaryrepairs.Re-linethestructurewithnewplasticaftereachcleaning.R0aofTorarConrWaofaiii.Whentemporaryconcretewashoutfacilitiesarenolongerrequiredforthework,thehardenedconcrete,slurriesandliquidsshallberemovedandproperlydisposedof..Materialsusedtoconstructtemporaryconcretewashoutfacilitiesshallberemovedfromthesiteoftheworkanddisposedoforrecycled..Holes,depressionsorothergrounddisturbancecausedbytheremovalofthetemporaryconcretewashoutfacilitiesshallbebackfilled,repaired,andstabilizedtopreventerosion.olitmeConstructionStorrnwaterPollutionFreentionuust20120 Figure4.1Ja—ConcreteWashoutAreaolumeConstructionStorrnwaterPollutionPreentionuust2012:-LL•t—E&:Tfr[r:J.rTh!j-.t:fEt”WIThP)STA1ES1t£“JIn(EE14rw-,IzrJf5ECflOA-AAN.nTi(rAi:)J:_HvARi\ILJbb\DCwnIPAS11CLNG4T1(AjTYPESELOWGRADr‘Acrn)ALi*çirPtwvNFtNTNFfl[LRihiONCI*ftW-t)UiStNSEEPA:L1;)Dfti1Aft’W!TKNr;apyLCNCkCftA,4DuAU1T0AI-%rqP{Ii4A---2POUCH—_wDTA)AE1B,_I/:‘B’srk’cfFI/-t1dPLA!flcLININCNOT10&TYPEABOVEGRADrwiThwoooPLANKS1 :ir:w,ii,/ML1’--10PS1/‘I_&4FAf;:t‘‘J:1—-DQN-‘lNUi_-1ThZhZZLNOTitALE7YpEA9OYEGRADrWITHSTRAWBMEStAUUALYOU)EiERWNDNTHi;HLW2THECO’RtTE*AkOWC4CSEflG4—15)SHALLfEI14SLLEDW1Th4iN10rnOTilETPR4CNcriTwA5*-ouTFAL’iIY.c;*.6/n1;—11mI;s—:—i—nFigure4.1.Zb—ConcreteWashoutAreaFigure4.18—PrefabricatedConcreteWashoutContainerwlRampoltirneConstructionStorrnwaterPollutionPreentioniiust201221ERE3kEt_;•ORsIA:Es{PUIWII)PLASI1CLtNNi-‘PLW1OflC——1C{)61frnf‘1P,—L.1tC%ITCONCRETE_LtCVLETIERS:wsieurI__J__i-lL_[At;IEWS*irn(12.nrr,j1j’L:‘CONCRETEWASHOUT$GNDtTML(OREQUIVALENT)‘H2OOrnrnIF—STAPLEDEWL‘1_STRAWBEtrp-) BMPC160:CertifiedErosionandSedimentControlLeadPurposeTheprojectproponentdesignatesatleastonepersonastheresponsiblerepresentativeinchargeoferosionandsedimentcontrol(ESC),andwaterqualityprotection.ThedesignatedpersonshallbetheCertifiedErosionandSedimentControlLead(CESCL)whoisresponsibleforensuringcompliancewithalllocal,state,andfederalerosionandsedimentcontrolandwaterqualityrequIrements.ConditionsofUseACE$CLshallbemadeavailableonprojectsoneacreorlargerthatdischargestormwatertosurfacewatersofthestate.SiteslessthanoneacremayhaveapersonwithoutCE$CLcertificationconductinspections;samplingisnotrequiredonsitesthatdisturblessthananacre..TheCE$CLshall:.HaveacurrentcertificateprovingattendanceinanerosionandsedimentcontroltrainingcoursethatmeetstheminimumESCtrainingandcertificationrequirementsestablishedbyEcology(seedetailsbelow).EcologywillmaintainalistofESCtrainingandcertificationprovidersat:http://www.ecy.wa.gov/prograrns/wq/storrnwater/cescl.htmlOR.BeaCertifiedProfessionalInErosionandSedimentControl(CPESC);foradditionalinformationgoto:www.cpesc.netSpecifications•Certificationshallremainvalidforthreeyears.•TheCE$CLshallhaveauthoritytoactonbehalfofthecontractorordeveloperandshallbeavailable,oron-call,24hoursperdaythroughouttheperiodofconstruction..TheConstructionSWPPPshallincludethename,telephonenumber,faxnumber,andaddressofthedesignatedCESCL..ACESCLmayprovideinspectionandcomplianceservicesformultipleconstructionprojectsinthesamegeographicregion.DutiesandresponsibilitiesoftheCESCLshallinclude,butarenotlimitedtothefollowing:.MaintainingpermitfileonsiteatalltimeswhichincludestheConstructionSWPPPandanyassociatedpermitsandplans..DirectingBMPinstallation,inspection,maintenance,modification,andremoval.olitmeConstructionStormwaterPollutionPreentionuust2012 .UpdatingallprojectdrawingsandtheConstructionSWPPPwithchangesmade..CompletinganysamplingrequirementsincludingreportingresultsusingWebDMR...Keepingdailylogs.andinspectionreports.Inspectionreportsshouldinclude:.Inspectiondate/time..Weatherinformation;generalconditionsduringinspectionandapproximateamountofprecipitationsincethelastinspection..AsummaryorlistofallBMPsimplemented.includingobservationsofallerosion/sedimentcontrolstructuresorpractices.Thefollowingshallbenoted:1.LocationsofBMPsinspected.2.LocationsofBMPsthatneedmaintenance.3.LocationsofBMPsthatfailedtooperateasdesignedorintended.4.LocationsofwhereadditionalordifferentBMPsarerequired..Visualmonitoringresults,includingadescriptionofdischargedstorrnwater.Thepresenceofsuspendedsediment,turbidwater,discoloration,andoilsheenshallbenoted,asapplicable..Anywaterqualitymonitoringperformedduringinspection..Generalcommentsandnotes,includingabriefdescriptionofanyBMPrepairs,maintenanceorinstallationsmadeasaresultoftheinspection..facilitate,participatein,andtakecorrectiveactionsresultingfrominspectionsperformedbyoutsideagenciesortheowner.BMPC162:SchedulingPitiposeSequencingaconstructionprojectreducestheamountanddurationofsoilexposedtoerosionbywind,rain,mnoff,andvehicletracking.ConditionsofUseTheconstructionsequencescheduleisanorderlylistingofallmajorland-disturbingactivitiestogetherwiththenecessaryerosionandsedimentationcontrolmeasuresplannedfortheproject.Thistypeofscheduleguidesthecontractoronworktobedonebeforeotherworkisstartedsothatseriouserosionandsedimentationproblemscanbeavoided.Followingaspecifiedworkschedulethatcoordinatesthetimingofland-disturbingactivitiesandtheinstallationofcontrolmeasuresisperhapsthemostcost-effectivewayofcontrollingerosionduringconstruction.TheremovalofsurfacegroundcoverleavesasitevulnerabletoacceleratedolumeConstructionStornn%’aterPollutionPreentionuitst2012 erosion.Constrtictionproceduresthatlimitlandclearingprovidetimelyinstallationoferosionandsedimentationcontrols,andrestoreprotectivecoverquicklycansignificantlyreducetheerosionpotentialofasite.Design.Minimizeconstructionduringrainyperiods.Co;;sidertitioiis.....Scheduleprojectstodisturboniysmallportrnnsofthesiteatanyonetime.Completegradingassoonaspossible.immediatelystabilizethedisturbedportionbeforegradingthenextportion.Practicestagedseedinginordertorevegetatecutandfillslopesastheworkprogresses.ohimeConstructionStorrnwaterPollutionPreentionuust2012 BMPC200:InterceptorDikeandSwalePuiposeProvidearidgeofcompactedsoiLoraridgewithanupsiopeswale.atthetoporbaseofadisturbedslopeoralongtheperimeterofadisturbedconstructionareatoconveystorrnwater.Usethedikeand/orsw&etointercepttherunofffromunprotectedareasanddirectittoareaswhereerosioncanbecontrolled.Thiscanpreventstormrunofffromenteringtheworkareaorsediment-ladenrunofffromleavingtheconstructionsite.ConditionsofUseWheretherunofffromanexposedsiteordisturbedslopemustbeconveyedtoanerosioncontrolfacilitywhichcansafelyconveythestorrnwater..Locateupslopeofaconstructionsitetopreventrunofffromenteringdisturbedarea..Whenplacedhorizontallyacrossadisturbedslope,itreducestheamountandvelocityofrunoffflowingdowntheslope..Locatedownslopetocollectrunofffromadisturbedareaanddirectwatertoasedimentbasin.Designand•Dikeand/orswaleandchannelmustbestabilizedwithtemporaryorInstallationpermanentvegetationorotherchannelprotectionduringconstruction.SpecificationsChannelrequiresapositivegradefordrainage;steepergradesrequirechannelprotectionandcheckdams.•Reviewconstructionforareaswhereovertoppingmayoccur.•Canbeusedattopofnewfillbeforevegetationisestablished.•Maybeusedasapermanentdiversionchanneltocarrytherunoff.•Sub-basintributaryareashouldbeoneacreorless.•Designcapacityforthepeakflowfroma10-year,24-hourstorm,assumingaType1Arainfalldistribution,fortemporaryfacilities.Alternatively,use1.6timesthe10-year,1-hourflowindicatedbyanapprovedcontinuousrunoffmodel.Forfacilitiesthatwillalsoserveonapermanentbasis,consultthelocalgovernment’sdrainagerequirements.Inrordishallmeetthefollowingcriteria:TopWidth2feetminimum.Height1.5feetminimumonbemiSideSlope2H:1Vorflatter.GradeDependsontopography,however,dikesystemminimumis0.5%,andmaximumis1%.CompactionMinimumof90percentASTMD698standardproctor.olumeConstructionStornni’aterPollutionFreentionuust2012 HorizontalSpacingofInterceptorDikes:AraSoSoPmFoaLn20H:1Vorless3-5%300feet(lOto2O)H:1V5-10%200feet(4to10)H:1V10-25%100feet(2to4)H:1V25-50%50feetStabilizationdependsonvelocityandreachSlopes<5%Seedandmulchappliedwithin5daysofdikeconstruction(seeBMPC121.Mulching).Slopes5-40%Dependentonrunoffvelocitiesanddikematerials.Stabilizationshouldbedoneimmediatelyusingeithersodorripraporothermeasurestoavoiderosion..Theupslopesideofthedikeshallprovidepositivedrainagetothedikeoutlet.Noerosionshalloccurattheoutlet.Provideenergydissipationn;easuresasnecessary.Sediment-ladenrunoffmustbereleasedthroughasedimenttrappingfacility..Minimizeconstructiontrafficovertemporarydikes.Usetemporarycrossculvertsforchannelcrossing.Inrorashallmeetthefollowingcriteria:2feetminimum;thecross-sectionbottomshallbelevel.1-footminimum.2H:lVorflatter.Maximum5percent,withpositivedrainagetoasuitableoutlet(suchasasedimentpond).SeedasperBMPC120,emoraranPermanentSeein,orFC202,Canizelmm,12inchesthickriprappressedintothebankandextendingatleast8inchesverticalfromthebottom..Inspectdiversiondikesandinterceptorswalesonceaweekandaftereveryrainfall.Immediatelyremovesedimentfromtheflowarea..Damagecausedbyconstructiontrafficorotheractivitymustberepairedbeforetheendofeachworkingday.Checkoutletsandmaketimelyrepairsasneededtoavoidgullyformation.Whentheareabelowthetemporarydiversiondikeispermanentlystabilized,removethedikeandfillandstabilizethechanneltoblendwiththenaturalsurface.BottomWidthDepthSideSlopeGradeStabilizationoluineConstructionStormwaterPollutionFreentionuust2012 BMPC201:Grass-LinedChannelsPuiposeToprovideachannelwithavegetativeliningforconveyanceofrunoff.SeeFigure4.2.1fortypicalgrass-linedchannels.Co;iditionsofUseThispracticeappliestoconstructionsiteswhereconcentratedrunoffneedstobecontainedtopreventerosionorflooding..Whenavegetativeliningcanprovidesufficientstabilityforthechannelcrosssectionandatlowervelocitiesofwater(normallydependentongrade).Thismeansthatthechannelslopesaregenerallylessthan5percentandspaceisavailableforarelativelylargecrosssection..Typicalusesincluderoadsideditches,channelsatpropertyboundaries,outletsfordiversions,andotherchannelsanddrainageditchesinlowareas..Channelsthatwillbevegetatedshouldbeinstalledbeforemajorearthworkandhydroseededwithabondedfibermatrix(BFM).Thevegetationshouldbewellestablished(i.e.,75percentcover)beforewaterisallowedtoflowintheditch.Withchannelsthatwillhavehighflows,erosioncontrolblanketsshouldbeinstalledoverthehydroseed.lfvegetationcannotbeestablishedfromseedbeforewaterisallowedintheditch,sodshouldbeinstalledinthebottomoftheditchinlieuofhydromuichandblankets.DesignandLocatethechannelwhereitcanconformtothetopographyandotherInstallationfeaturessuchasroads.Specifications•Locatethemtousenaturaldrainagesystemstothegreatestextentpossible..Avoidsharpchangesinalignmentorbendsandchangesingrade..Donotreshapethelandscapetofitthedrainagechannel..Themaximumdesignvelocityshallbebasedonsoilconditions,typeofvegetation,andmethodofrevegetation,butatnotimesshallvelocityexceed5feet/second.Thechannelshallnotbeovertoppedbythepeakrunofffroma10-year,24-hourstorm,assumingaType1Arainfalldistribution.”Alternatively,use1.6timesthe10-year,1-hourflowindicatedbyanapprovedcontinuousrunoffmodeltodetermineaflowratewhichthechannelmustcontain..Wherethegrass-linedchannelwillalsofunctionasapermanentstormwaterconveyancefacility,consultthedrainageconveyancerequirementsofthelocalgovernmentwithjurisdiction.ohimeConstructionStormwaterPollutionPreentionuust2012 .Anestablishedgrassorvegetatedliningisrequiredbeforethechannelcanbeusedtoconveystormwater,unlessstabilizedwithnetsorblankets..Ifdesignvelocityofachanne’tobevegetatedbyseedingexceeds2ft/sec.atemporarychannellinerisrequired.Geotextileorspecialmulchprotectionsuchasfiberglassrovingorstrawandnettingprovidesstabilityuntilthevegetationisfullyestablished.Seefigure4.2.2..Checkdarnsshallberemovedwhenthegrasshasmaturedsufficientlytoprotecttheditchorswaleunlesstheslopeoftheswaleisgreaterthan4percent.Theareabeneaththecheckdarnsshallbeseededandmulchedimmediatelyafterdamremoval..lfvegetationisestablishedbysodding,thepermissiblevelocityforestablishedvegetationmaybeusedandnotemporarylinerisneeded..Donotsubjectgrass-linedchanneltosedimentationfromdisturbedareas.Usesediment-trappingBMPsupstreamofthechannel..V-shapedgrasschannelsgenerallyapplywherethequantityofwaterissmall,suchasinshortreachesalongroadsides.TheV-shapedcrosssectionisleastdesirablebecauseitisdifficulttostabilizethebottomwherevelocitiesmaybehigh..Trapezoidalgrasschannelsareusedwheren;noffvolumesarelargeandslopeislowsothatvelocitiesarenonerosivetovegetatedlinings.(Note:itisdifficulttoconstructsmallparabolicshapedchannels.).Subsurfacedrainage,orriprapchannelbottoms,maybenecessaryonsitesthataresubjecttoprolongedwetconditionsduetolongdurationflowsorahighwatertable..Provideoutletprotectionatculvertendsandatchannelintersections..Grasschannels,ataminimum,shouldcarrypeakrunofffortemporaryconstructiondrainagefacilitiesfromthe10-year,24-hourstormwithouteroding.Wherefloodhazardexists,increasethecapacityaccordingtothepotentialdamage..Grassedchannelsideslopesgenerallyareconstructed3H:lVorflattertoaidintheestablishmentofvegetationandformaintenance..Constructchannelsaminimumof0.2footlargeraroundtheperipherytoallowforsoilbulkingduringseedbedpreparationsandsodbuildup.MaintenanceDuringtheestablishmentperiod,checkgrass-linedchannelsaftereveryStandardsrainfall..Aftergrassisestablished,periodicallycheckthechannel;checkitaftereveryheavyrainfallevent.Inimediatelymakerepairs..Itisparticularlyimportanttocheckthechanneloutletandallroadcrossingsforbankstabilityandevidenceofpipingorscourholes.olumeConstructionStorrnwaterPollutionPreentionuust20120 .Renioveallsignificantsedimentaccuiu1ationstomaintainthedesignedcarryingcapacity.Keepthegrassinahealthy.vigorousconditionatalltimes,sinceitistheprimaryerosionprotectionforthechannel.TypicalVShapedChannelCross-sectionC\rsjeGr-Li’’dI.j’‘q1].:‘;;:4tLI,:-.‘.S._r-:.>/\.EIL-\../.‘:si5-Z5”iti1Fiic•/;/\‘••KeyinFajfc.:.:__WithRockCentetTypicalParabolicChannelCross-Section/LWithGhneILiner“?.‘.%/\•-,:!.-.,,-,.J4•\.‘_\V.’.‘.t.\6-9,/t;:;-•.fl:O225mrr‘,\FtlteiKeyInF-abti’,-\/_</%%./Fabric—WtihRoekCenierlotGaspFtowFigure4.2.1—TypicalGrass-LinedChannelsolumeConstructionStorrnwaterPollutionFreentionuust2012TypicalTrapezoidalChannelCross-SectionOestqflDepth)vercutcflannel2’(5UmmhIlohijtkindurinqsedbectpeparatonandwwtnt:iveetOnFlow1 Overlapti50mm)mn1rwjr1IntermittentCheckSlotmats.LongitudinalAnchorTrenchFigure4.2.2—TemporaryChannelLinersolumeConstructionStor,nv’aterPollutionPreentionuust20122E:cI;3[Gic..::j(f(j.cS!:c:v;nIOVERCTCHANNEL2(50mm)TOALLOWBLKINRINSEEBEPREPARATiONt:ri[r:r‘-‘a->/,‘tv-,1‘5’r)TPICALINSTALLATIONIWITHEROSIONCONTROLIBLANKETSORTRF4TREINFORCEENTATSShingle-lapsplicedendsorbeginnewrollinanintermittentcheckslot4Preparesoilandapplyseedbeforeinstallingblankets,matsorothertemporarychannellinersystem4NOTES:IDesignvelocitiesexceeding2ft/sec(O.5mlsec)requiretemporaryblankets,matsorsimilarlinerstoprotectseedandsoiluntilvegetationbecomesestablished.2Grass-linedchannelswithdesignvelocitiesexceeding6ft/sec(2ni’sec)shouldincludeturfreinforcement BMPC202:ChannelLiningPuiposeToprotectchannelsbyprovidingachannellinerusingeitherblanketsorriprap.CojiditionsofWhennaturalsoilsorvegetatedstabilizedsoilsinachannelarenotadequatUcetopreventchannelerosion..Whenapermanentditchorpipesystemistobeinstalledandatemporarymeasureisneeded..Inalmostallcases,syntheticandorganiccoconutblanketsaremoreeffectivethanriprapforprotectingchannelsfromerosion.Blanketscanbeusedwithandwithoutvegetation.Blanketedchannelscanbedesignedtohandleanyexpectedflowandlongevityrequirement.Somesyntheticblanketshaveapredictedlifespanof50yearsormore,eveninsunlight.SOtherreasonswhyblanketsarebetterthanrockincludetheavailabilityofblanketsoverrock.Inmanyareasofthestate,rockisnoteasilyobtainableorisveryexpensivetohaultoasite.Blanketscanbedeliveredanywhere.Rockrequirestheuseofdumptruckstohaulandheavyequipmenttoplace.Blanketsusuallyonlyrequirelaborerswithhandtools,andsometimesabackhoe..TheFederalHighwayAdministrationrecommendsnotusingflexiblelinerswhenevertheslopeexceeds10percentortheshearstressexceeds8lbs/ft2.DesignandSeeBMPC122forinformationonblankets.Installation.......Sinceriprapisusedwhereerosionpotentialishigh,constructionmustbeSpecifications......sequencedsothatthenprapisputinplacewiththeminimumpossibledelay..Disturbanceofareaswhereriprapistobeplacedshouldbeundertakenonlywhenfmalpreparationandplacementoftheriprapcanfollowimmediatelybehindtheinitialdisturbance.Whereriprapisusedforoutletprotection,theriprapshouldbeplacedbeforeorinconjunctionwiththeconstructionofthepipeorchannelsothatitisinplacewhenthepipeorchannelbeginstooperate..Thedesigner,afterdeterminingtheriprapsizethatwillbestableundertheflowconditions,shallconsiderthatsizetobeaminimumsizeandthen,basedonriprapgradationsactuallyavailableinthearea,selectthesizeorsizesthatequalorexceedtheminimumsize.Thepossibilityofdrainagestructuredamagebychildrenshallbeconsideredinselectingariprapsize,especiallyifthereisnearbywateroragullyinwhichtotossthestones..Stoneforriprapshallconsistoffieldstoneorquarrystoneofapproximatelyrectangularshape.ThestoneshallbehardandangularolumeConstnictionStorrnv’aterPollutionFreentionuust2012 andofsuchqualitythatitwillnotdisintegrateonexposuretowaterorweatheringanditsimlibesuitableinallrespectsforthepurposeintended..Aliningofengineeringfilterfabric(geotextile)shallbeplacedbetweentheriprapandtheunderlyingsoilsurfacetopreventsoilmovementintoorthroughtheriprap.Thegeotextileshouldbekeyedinatthetopofthebank..filterfabricshallnotbetisedonslopesgreaterthanl-1/2H:1Vasslippagemayoccur.Itshouldbeusedinconjunctionwithalayerofcoarseaggregate(granularfilterblanket)whentheripraptobeplacedis12inchesandlarger.BMPC203:WaterBarsPurposeAsmallditchorridgeofmaterialisconstructeddiagonallyacrossaroadorright-of-waytodivertstorrnwaterrunofffromtheroadsurface,wheeltracks,orashallowroadditch.Seefigure4.2.3.ConditionsofuseClearingright-of-wayandconstructionofaccessforpowerlines,pipelines,andothersimilarinstallationsoftenrequirelongnarrowright-of-waysoverslopingterrain.Disturbanceandcompactionpromotesgullyformationintheseclearedstripsbyincreasingthevolumeandvelocityofrunoff.Gullyformationmaybeespeciallysevereintiretracksandruts.Topreventgullying,runoffcanoftenbedivertedacrossthewidthoftheright-of-waytoundisturbedareasbyusingsmallpredesigneddiversions..Givespecialconsiderationtoeachindividualoutletarea,aswellastothecumulativeeffectofaddeddiversions.Usegraveltostabilizethediversionwheresignificantvehiculartrafficisanticipated.DesignandHeight:8-inchminimummeasuredfromthechannelbottomtotheridgetop.Installation..Sideslopeofchannel:2H:lVmaximum;3H:1VorflatterwhenSpecificatw;;s•vehicleswillcross..Basewidthofridge:6-inchminimum..Locatethemtousenaturaldrainagesystemsandtodischargeintowellvegetatedstableareas..GuidelineforSpacing:SoSam(f)<51255-1010010-207520-3550>35UserocklinedditchohimeConstructio,iStormwaterPollutionPreentionuust20]2 .Gradeofwaterbarandangle:Selectanglethatresultsinditchslopelessthan2percent..Installassoonastheclearingandgradingiscomplete.Reconstructwhenconstructioniscompleteonasectionwhenutilitiesarebeinginstalled..Cornpacttheridgewheninstalled..Stabilize,seedandmulchtheportionsthatarenotsubjecttotraffic.Graveltheareascrossedbyvehicles.MaintenancePeriodicallyinspectright-of-waydiversionsforwearandaftereveryheavyStandardsrainfallforerosiondamage..Immediatelyremovesedimentfromtheflowareaandrepairthedike..Checkoutletareasandmaketimelyrepairsasneeded..Whenpermanentroaddrainageisestablishedandtheareaabovethetemporaryright-of-waydiversionispermanentlystabilized,removethedikesandfillthechanneltoblendwiththenaturalground,andappropriatelystabilizethedisturbedarea.DEEPWATERBARA24to30inchesB6to1OfeSHALLOWWATERBARA8to12inchesB6to12feFigure4.2.3—WaterBarolitmeConstructionStornnvaterPollutionPreentionuust2012 BMPC204:PipeSlopeDrainsPuiposeTouseapipetoconveystormwatcranytimewaterneedstobedivertedawayfromoroverbaresoiltopreventgullies,channelerosion,andsaturationofslide-pronesoils.Co;tditionsofUsePipeslopedrainsshouldbeusedwhenatemporaryorpermanentstormwaterconveyanceisneededtomovethewaterdownasteepslopetoavoiderosion(figure4.2.4).Onhighwayprojects,pipeslopedrainsshouldbeusedatbridgeendstocollectrunoffandpipeittothebaseofthefillslopesalongbridgeapproaches.Thesecanbedesignedintoaprojectandincludedasbiditems.Anotheruseonroadprojectsistocollectrunofffrompavementandpipeitawayfromsideslopes.Theseareusefulbecausethereisgenerallyatimelagbetweenhavingthefirstliftofasphaltinstalledandthecurbs,gutters,andpermanentdrainageinstalled.Usedinconjunctionwithsandbags,orothertemporarydiversiondevices,thesewillpreventmassiveamountsofsedimentfromleavingaproject.Watercanbecollected,channeledwithsandbags,TriangularSiltDikes,berms,orothermaterial,andpipedtotemporarysedimentponds.Pipeslopedrainscanbe:.Connectedtonewcatchbasinsandusedtemporarilyuntilallpermanentpipingisinstalled;.Usedtodrainwatercollectedfromaquifersexposedoncutslopesandtakeittothebaseoftheslope;.Usedtocollectcleanrunofffromplasticsheetinganddirectitawayfromexposedsoil;.Installedinconjunctionwithsiltfencetodraincollectedwatertoacontrolledarea;.Usedtodivertsmallseasonalstreamsawayfromconstruction.Theyhavebeenusedsuccessfullyonculvertreplacementandextensionjobs.Largeflexpipecanbeusedonlargerstreamsduringculvertremoval,repair,orreplacement;and,.Connectedtoexistingdownspoutsandroofdrainsandusedtodivertwaterawayfromworkareasduringbuildingrenovation,demolition,andconstructionprojects.Therearenowseveralcommerciallyavailablecollectorsthatareattachedtothepipeinletandhelppreventerosionattheinlet.ohti;zeConstructionStornnvaterPollutionPreentionuust2012 DesignandSizethepipetoconveytheflow.ThecapacityfortemporarydrainsshallbeIi;stctllationsufficienttohandlethepeakflowfroma10-year,24-hourstormevent,SpecificcttionsassumingaType1Arainfalldistribtition.Alternatively.use1.6timesthe10-year,1-hourflowindicatedbyanapprovedcontinuousrunoffmodel.Consultlocaldrainagerequirementsforsizingpenanentipeslopedrains..Usecareinclearingvegetatedslopesforinstallation..Re-establishcoverimmediatelyonareasdisturbedbyinstallation..Usetemporarydrainsonnewcutorfillslopes..Usediversiondikesorswalestocollectwateratthetopoftheslope..Ensurethattheentranceareaisstableandlargeenoughtodirectflowintothepipe..Pipingofwaterthroughthebermattheentranceareaisacommonfailuremode..Theentranceshallconsistofastandardflaredendsectionforculverts12inchesandlargerwithaminimum6-inchmetaltoeplatetopreventrunofffromundercuttingthepipeinlet.Theslopeoftheentranceshallbeatleast3percent.Sandbagsmayalsobeusedatpipeentrancesasatemporarymeasure..Thesoilaroundandunderthepipeandentrancesectionshallbethoroughlycompactedtopreventundercutting..Theflaredinletsectionshallbesecurelyconnectedtotheslopedrainandhavewatertightconnectingbands..Slopedrainsectionsshallbesecurelyfastenedtogether,fusedorhavegasketedwatertightfittings,andshallbesecurelyanchoredintothesoil..Thrustblocksshouldbeinstalledanytime90degreebendsareutilized.Dependingonsizeofpipeandflow,thesecanbeconstructedwithsandbags,strawbalesstakedinplace,“t”postsandwire,orecologyblocks..Pipeneedstobesecuredalongitsfulllengthtopreventmovement.Thiscanbedonewithsteel“t”postsandwire.Apostisinstalledoneachsideofthepipeandthepipeiswiredtothem.Thisshouldbedoneevery10-20feetofpipelengthorso,dependingonthesizeofthepipeandquantityofwatertodivert..Interceptordikesshallbeusedtodirectrunoffintoaslopedrain.Theheightofthedikeshallbeatleast1foothigheratallpointsthanthetopoftheinletpipe..Theareabelowtheoutletmustbestabilizedwithariprapapron(seeBMPC209OutletProtection,fortheappropriateoutletmaterial).olumeConstructionStol7nwaterPollutionPreentionuust2012 4Iai;itei,anceStttndards.Ifthepipeslopedrainisconveyingsediment-ladenwater,directallflowsintothesedinenttrappingfacility..Materialsspecificationsforanypermanentpipedsystemshallbesetbythelocalgovernment.Checkinletandoutletpointsregularly,especiallyaflerstorms.Theinletshouldbefreeofundercutting,andnowatershouldbegoingaroundthepointofentry.Ifthereareproblems,theheadwallshouldbereinforcedwithcompactedearthorsandbags..Theoutletpointshouldbefreeoferosionandinstalledwithappropriateoutletprotection..forpermanentinstallations,inspectpipeperiodicallyforvandalismandphysicaldistresssuchasslidesandwind-throw..Normallythepipeslopeissosteepthatcloggingisnotaproblemwithsmoothwallpipe,however,debrismaybecomelodgedinthepipe.Figure4.2.4—PipeSlopeDrainDikematerialcompacted90%modifiedproctorCPEPorequivalentpipeDischargetoastabilizedwatercourse,sedimentretentionfacility,orstabilizedoutletStandardflaredendsectionInletandallsectionsmustbesecurelyfastenedtogetherwithgasketedwatertightfittingsoltimeConstructionStormwaterPollutionPreentionUust2012 BMPC205:SubsurfaceDrainsPitiposeTointercept,collect,andconveygroundwatertoasatisfactoryoutlet,usingaperforatedpipeorconduitbelowthegroundsurface.Subsurfacedrainsarealsoknownas“frenchdrains.”Theperforatedpipeprovidesadewateringmechanismtodrainexcessivelywetsoils,provideastablebaseforconstruction,improvestabilityofstructureswithshallowfoundations,ortoreducehydrostaticpressuretoimproveslopestability.ConditionsofUseUsewhenexcessivewatermustberemovedfromthesoil.Thesoilpermeability,depthtowatertableandimperviouslayersareallfactorswhichmaygoverntheuseofsubsurfacedrains.DesignandRIfdrainareusedeithertolowerthewatertableinlarge,relativelyIi,stallatio,;flatareas,improvethegrowthofvegetation,ortoremovesurfacewater.SpecificationsReliefdrainsareinstalledalongaslopeanddraininthedirectionoftheslope.Theycanbeinstalledinagridpattern,ahe;Tingbonepattern,orarandompattern..Inrordrainareusedtoremoveexcessgroundwaterfromaslope,stabilizesteepslopes,andlowerthewatertableimmediatelybelowaslopetopreventthesoilfrombecomingsaturated.Interceptordrainsareinstalledperpendiculartoaslopeanddraintothesideoftheslope.Theyusuallyconsistofasinglepipeorseriesofsinglepipesinsteadofapatternedlayout..Dandainofinrordrain--Thedepthofaninterceptordrainisdetenninedprimarilybythedepthtowhichthewatertableistobeloweredorthedepthtoaconfininglayer.Forpracticalreasons,themaximumdepthisusuallylimitedto6feet,withaminimumcoverof2feettoprotecttheconduit..Thesoilshouldhavedepthandsufficientpermeabilitytopermitinstallationofaneffectivedrainagesystematadepthof2to6feet..Anadequateoutletforthedrainagesystemmustbeavailableeitherbygravityorbypumping..Thequantityandqualityofdischargeneedstobeaccountedforinthereceivingstream(additionaldetentionmayberequired)..Thisstandarddoesnotapplytosubsurfacedrainsforbuildingfoundationsordeepexcavations..Thecapacityofaninterceptordrainisdeterminedbycalculatingthemaximumrateofgroundwaterflowtobeintercepted.Therefore,itisolumeConstructionStol7mi’aterPollutionPreentionuust2012 goodpracticetomakecompletesubsurfaceinvestigations,includinghydraulicconductivityofthesoil,beforedesigningasubsurfacedrainagesystem..Siofdrain--Sizesubsurfacedrainstocarrytherequiredcapacitywithoutpressureflow.Minimumdiameterforasubsurfacedrainis4inches..Theminimumvelocityrequiredtopreventsiltingis1.4ft./sec.Thelineshallbegradedtoachievethisvelocityataminimum.Themaximumallowablevelocityusingasand-gravelfilterorenvelopeis9ft/sec..Filtermaterialandfabricshallbeusedaroundalldrainsforproperbeddingandfiltrationoffinematerials.Envelopesandfiltersshouldsurroundthedraintoaminimumof3-inchthickness..Theoutletofthesubsurfacedrainshallemptyintoasedimentpondthroughacatchbasin.Iffreeofsediment.itcanthenemptyintoareceivingchannel,swale,orstablevegetatedareaadequatelyprotectedfromerosionandundermining..Thetrenchshallbeconstructedonacontinuousgradewithnoreversegradesorlowspots..Softoryieldingsoilsunderthedrainshallbestabilizedwithgravelorothersuitablematerial..Backfillingshallbedoneimmediatelyafterplacementofthepipe.Nosectionsofpipeshallremainuncoveredovernightorduringarainstorm.Backfillmaterialshallbeplacedinthetrenchinsuchamannerthatthedrainpipeisnotdisplacedordamaged..Donotinstallpermanentdrainsneartreestoavoidthetreerootsthattendtoclogtheline.Usesolidpipewithwatertightconnectionswhereitisnecessarytopassasubsurfacedrainagesystemthroughastandoftrees..0--Ensurethattheoutletofadrainemptiesintoachamelorotherwatercourseabovethenormalwaterlevel..Secureananimalguardtotheoutletendofthepipetokeepoutrodents..Useoutletpipeofcorrugatedmetal,castiron,orheavy-dutyplasticwithoutperforationsandatleast10feetlong.Donotuseanenvelopeorfiltermaterialaroundtheoutletpipe,andburyatleasttwo-thirdsofthepipelength..Whenoutletvelocitiesexceedthoseallowableforthereceivingstream,outletprotectionmustbeprovided.olitnieConstructionStorinwaterPollutionPreentionuust20120 MabitenaliceSubsurfacedrainsshallbecheckedperiodicallytoensurethattheyareStaizclards.free-flowingandnotcloggedwithsedimentorroots..Theoutletshallbekeptcleanandfreeofdebris..Surfaceinletsshallbekeptopenandfreeofsedimentandotherdebris..Treeslocatedtooclosetoasubsurfacedrainoftenclogthesystemwiththeirroots.Ifadrainbecomesclogged.relocatethedrainorremovethetreesasalastresort.Drainplacementshouldbeplannedtominimizethisproblem..Wheredrainsarecrossedbyheavyvehicles,thelineshallbecheckedtoensurethatitisnotcrushed.BMPC206:LevelSpreaderPuiposeToprovideatemporaryoutletfordikesanddiversionsconsistingofanexcavateddepressionconstructedatzerogradeacrossaslope.Toconvertconcentratedrunofftosheetflowandreleaseitontoareasstabilizedbyexistingvegetationoranengineeredfilterstrip.ConditionsofUseUsedwhenaconcentratedflowofwaterneedstobedispersedoveralargeareawithexistingstablevegetation..Itemstoconsiderare:1.Whatistheriskoferosionordamageiftheflowmaybecomeconcentrated?2.Isaneasementrequiredifdischargedtoadjoiningproperty?3.Mostoftheflowshouldbeasgroundwaterandnotassurfaceflow.4.Isthereanunstableareadownstreamthatcannotacceptadditionalgroundwater?.Useonlywheretheslopesaregentle,thewatervolumeisrelativelylow,andthesoilwilladsorbmostofthelowflowevents.DesignandUseaboveundisturbedareasthatarestabilizedbyexistingvegetation.InstallationIfthelevelspreaderhasanylowpoints,flowwillconcentrate,createSpecificatioitschannelsandmaycauseerosion..Dischargeareabelowtheoutletmustbeuniformwithaslopeflatterthan5H:1V..Outlettobeconstructedlevelinastable,undisturbedsoilprofile(notonfill)..Therunoffshallnotre-concentrateafterreleaseunlessinterceptedbyanotherdownstreammeasure.olumeConstructionStormwaterPollutionFreentionuust20121 .Thegradeofthechannelforthelast20feetofthedikeorinterceptorenteringthelevelspreadershallbelessthanorequaltoIpercent.Thegradeofthelevelspreadershallbe0percenttoensureuniformspreadingofstormrunoff.IA6-inchhighgravelbermplacedacrossthelevellipshallconsistofwashedcrushedrock,2-to4-inchor3/4-inchto1-inchsize..Thespreaderlengthshallbedeterminedbyestimatingthepeakflowexpectedfromthe10-year,24-hourdesignstorm.Thelengthofthespreadershallbeaminimumof15feetfor0.1cfsandshallincreaseby10feetforeach0.1cfsthereaftertoamaximumof0.5cfsperspreader.Usemultiplespreadersforhigherflows..Thewidthofthespreadershouldbeatleast6feet.MaintenanceStandards.Thedepthofthespreaderasmeasuredfromthelipshouldbeatleast6inchesanditshouldbeuniformacrosstheentirelength..Levelspreadersshallbesetbackfromthepropertylineunlessthereisaneasementforflow..Levelspreaders,wheninstalledeverysoofteningrassyswales,keeptheflowsfromconcentrating.Materialsthatcanbeusedincludesandbags,lumber,logs,concrete,andpipe.Tofunctionproperly,thematerialneedstobeinstalledlevelandoncontour.Figures4.2.5Figure425and4.2.6provideacross-sectionandadetailofalevelspreader.Acappedperforatedpipecouldalsobeusedasaspreader.Thespreadershouldbeinspectedaftereveryrunoffeventtoensurethatitisfunctioningcorrectly..Thecontractorshouldavoidtheplacementofanymaterialonthestructureandshouldpreventconstructiontrafficfromcrossingoverthestructure..Ifthespreaderisdamagedbyconstructiontraffic,itshallbeimmediatelyrepaired.olunieConstructionStormwaterPollutionPreentionuust2012Pressure-Treated2”xl0”DenselyvegetatedforaMm.of100’ands’opelessthan5:1Figure4.2.5—CrossSectionofLevelSpreader2 Piti-poseConstructionofsmalldarnsacrossaswaleorditchreducesthevelocityofconcentratedflowanddissipatesenergyatthecheckdam.ConditionsofUseWheretemporarychannelsorpermanentchannelsarenotyetvegetated,channelliningisinfeasible,and/orvelocitychecksarerequired..CheckdamsmaynotbeplacedinstreamsunlessapprovedbytheStateDepartmentofFishandWildlife.Checkdamsmaynotbeplacedinwetlandswithoutapprovalfromapermittingagency..DonotplacecheckdamsbelowtheexpectedbackwaterfromanysalmonidbearingwaterbetweenOctober1andMay31toensurethatthereisnolossofhighflowrefugehabitatforoverwinteringjuvenilesalmonidsandemergentsalmonidfry..Constructrockcheckdarnsfromappropriatelysizedrock.Therockusedmustbelargeenoughtostayinplacegiventheexpecteddesignflowthroughthechannel.Therockmustbeplacedbyhandorbymechanicalmeans(nodumpingofrocktoformdam)toachievecompletecoverageoftheditchorswaleandtoensurethatthecenterofthedamislowerthantheedges..Checkdamsmayalsobeconstructedofeitherrockorpea-gravelfilledbags.Numerousnewproductsarealsoavailableforthispurpose.Theytendtobere-usable,quickandeasytoinstall,effective,andcostefficient..Placecheckdamsperpendiculartotheflowofwater..Thedarnshouldformatrianglewhenviewedfromtheside.Thispreventsundercuttingaswaterflowsoverthefaceofthedamratherthanfallingdirectlyontotheditchbottom.SpreadermustbelevelTreated2xlOmaybeabuttedendtoendformax.spreaderlengthof50rEi-[TTE1IImm.A18”miii.rebarsupports8max.spacingFigure4.2.6—DetailofLevelSpreaderBMPC207:CheckDamsolumeConstructionStorinv’aterPollutionFreentionuust2012 .Beforeinstallingcheckdamsimpoundandbypassupstreamwaterflowawayfromtheworkarea.Optionsforbypassingincludepumps,siphons,ortemporarychannels..Checkdamsinassociationwithsumpsworkmoreeffectivelyatslowingflowandretainingsedimentthanjustacheckdarnalone.Adeepsumpshouldbeprovidedimmediatelyupstreamofthecheckdarn..Insomecases,ifcarefullylocatedanddesigned,checkdarnscanremainaspermanentinstallationswithveryminorregrading.Theymaybeleftaseitherspiliways,inwhichcaseaccumulatedsedimentwouldbegradedandseeded,orascheckdarnstopreventfurthersedimentfiornleavingthesite..Themaximumspacingbetweenthedarnsshallbesuchthatthetoeoftheupstreamdarnisatthesameelevationasthetopofthedownstreamdarn..Keepthemaximumheightat2feetatthecenterofthedarn..Keepthecenterofthecheckdarnatleast12incheslowerthantheouteredgesatnaturalgroundelevation.IKeepthesideslopesofthecheckdarnat2H:1Vorflatter..Keythestoneintotheditchbanksandextenditbeyondtheabutmentsaminimumof18inchestoavoidwashoutsfromoverflowaroundthedarn..Usefilterfabricfoundationunderarockorsandbagcheckdam.Ifablanketditchlinerisused,filterfabricisnotnecessary.Apieceoforganicorsyntheticblanketcuttofitwillalsoworkforthispurpose..Inthecaseofgrass-linedditchesandswales,allcheckdarnsandaccumulatedsedimentshallberemovedwhenthegrasshasmaturedsufficientlytoprotecttheditchorswale-unlesstheslopeoftheswaleisgreaterthan4percent.Theareabeneaththecheckdarnsshallbeseededandmulchedimmediatelyafterdamremoval..Ensurethatchannelappurtenances,suchasculvertentrancesbelowcheckdarns,arenotsubjecttodamageorblockagefromdisplacedstones.Figure4.2.7depictsatypicalrockcheckdarn.MaintenanceCheckdamsshallbemonitoredforperformanceandsedimentStandardsaccumulationduringandaftereachrunoffproducingrainfall.Sedimentshallberemovedwhenitreachesonehalfthesumpdepth..Anticipatesubmergenceanddepositionabovethecheckdamanderosionfromhighflowsaroundtheedgesofthedarn..Ifsignificanterosionoccursbetweendams,installaprotectiveripraplinerinthatportionofthechannel.oltiineConstructionStormwaterPollutionFreentionuust2012 ApprovedasEcologyhasapprovedproductsasabletomeettherequirementsofBMPEquivalentC207.TheproductsdidnotpassthroughtheTecimologyAssessmentProtocol—Ecology(TAPE)process.Localjurisdictionsmaychoosenottoacceptthisproductapprovedasequivalent,ormayrequireadditionaltestingpriortoconsiderationforlocaluse.TheproductsareavailableforreviewonEcology’swebsiteathttp:/!www.ecy.wa.gov/programs/wq/stormwater/newtech!eguivalent.htmlohimeConstructionStorrnwaterPollutionPreentionuust2012 olumeConstructionStormwaterPollutionPreentionuust2012Figure4.2.7—RockCheckDam BMPC208:TriangularSiltDike(TSD)(Geotextile-EncasedCheckDam)Pu;poseTriangularsiltdikesmaybeusedascheckdams,forperimeterprotection.fortemporarysoilstockpileprotection,fordropinletprotection,orasatemporaryinterceptordike.Conditionsofuse•Maybeusedonsoilorpavementwithadhesiveorstaples.•TSDshavebeenusedtobuildtemporary:1.sedimentponds;2.diversionditches;3.concretewashoutfacilities;4.curbing;5.waterbars;6.levelspreaders;and,7.berms.DesignandMadeofurethanefoamsewnintoawovengeosyntheticfabric.Instatlatio;;.......Itistriangular,10inchesto14incheshighinthecenter,witha20-inchtopec;icatwns28-inchbase.A2—footapronextendsbeyondbothsidesofthetrianglealongitsstandardsectionof7feet.Asleeveatoneendallowsattachmentofadditionalsectionsasneeded.•Installwithendscurveduptopreventwaterfromflowingaroundtheends.•Thefabricflapsandcheckdarnunitsareattachedtothegroundwithwirestaples.WirestaplesshouldbeNo.11gaugewireandshouldbe200mmto300mniinlength.•Whenmultipleunitsareinstalled,thesleeveoffabricattheendoftheunitshalloverlaptheabuttingunitandbestapled.•Checkdamsshouldbelocatedandinstalledassoonasconstructionwillallow.•Checkdamsshouldbeplacedperpendiculartotheflowofwater.•Whenusedascheckdams,theleadingedgemustbesecuredwithrocks,sandbags,orasmallkeyslotandstaples.•Inthecaseofgrass-linedditchesandswales,checkdamsandaccumulatedsedimentshallberemovedwhenthegrasshasmaturedsufficientlytoprotecttheditchorswaleunlesstheslopeoftheswaleisgreaterthan4percent.Theareabeneaththecheckdamsshallbeseededandmulchedimmediatelyafterdarnremoval.Maintenance•TriangularsiltdamsshallbeinspectedforperformanceandsedimentoluineConstructionStonnwaterPollutionPreentionulist2012 Stttndardsaccumulationduringandaftereachrunoffproducingrainfall.Sedimentshallberemovedwhenitreachesonehalftheheightofthedarn..Anticipatesubmergenceanddepositionabovethetriangularsiltdarnanderosionfromhighflowsaroundtheedgesofthedarn.Immediatelyrepairanydamageoranyundercuttingofthedarn.BMPC209:OutletProtectionPurposeOutletprotectionpreventsscouratconveyanceoutletsandminimizesthepotentialfordownstreamerosionbyreducingthevelocityofconcentratedstorrnwaterflows.ConditionsofuseOutletprotectionisrequiredattheoutletsofallponds,pipes,ditches,orotherconveyances,andwhererunoffisconveyedtoanaturalormanmadedrainagefeaturesuchasastream,wetland,lake,orditch.DesignandThereceivingchannelattheoutletofaculvertshallbeprotectedfromInstallationerosionbyrockliningaminimumof6feetdownstreamandextendingupSpecificationsthechannelsidesaminimumof1—footabovethemaximumtailwaterelevationor1-footabovethecrown,whicheverishigher.Forlargepipes(morethan18inchesindiameter),theoutletprotectionliningofthechannelislengthenedtofourtimesthediameteroftheculvert..Standardwingwalls,andtaperedoutletsandpavedchannelsshouldalsobeconsideredwhenappropriateforpermanentculvertoutletprotection.(SeeWSDOTHydraulicManual,availablethroughW$DOTEngineeringPublications)..Organicorsyntheticerosionblankets,withorwithoutvegetation,areusuallymoreeffectivethanrock,cheaper,andeasiertoinstall.Materialscanbechosenusingmanufacturerproductspecifications.ASTMtestresultsareavailableformostproductsandthedesignercanchoosethecorrectmaterialfortheexpectedflow..Withlowflows,vegetation(includingsod)canbeeffective..Thefollowingguidelinesshallbeusedforriprapoutletprotection:1.Ifthedischargevelocityattheoutletislessthan5fps(pipeslopelessthan1percent),use2-inchto8-inchriprap.Minimumthicknessis1-foot.2.For5to10fpsdischargevelocityattheoutlet(pipeslopelessthan3percent),use24-inchto48-inchriprap.Minimumthicknessis2feet.3.Foroutletsatthebaseofsteepslopepipes(pipeslopegreaterthan10percent),anengineeredenergydissipatershallbeused.SFilterfabricorerosioncontrolblanketsshouldalwaysbeusedunderripraptopreventscourandchannelerosion.olumeConstructionStol7nwaterPollutionPreentionuust2012 .Newpipeoutfallscanprovideanopportunityforlow-costfishhabitatimprovements.forexample,analcoveoflow-velocitywatercanbecreatedbyconstructingthepipeoutfallandassociatedenergydissipaterbackfromthestreamedgeanddiggingachanneLover-widenedtotheupstreamside.fromtheoutfall.Overxvinteringjuvenileandmigratingadultsalmonidsmayusethealcoveasshelterduringhighflows.Bankstabilization,bioengineering,andhabitatfeaturesmayberequiredfordisturbedareas.ThisworkmayrequireaHPA.SeeVolumeVformoreinformationonoutfallsystemdesign.Maintenance•inspectandrepairasneeded.Standards...•Addrockasneededtomaintaintheintendedfunction.•Cleanenergydissipaterifsedimentbuildsup.BMPC220:StormDrainInletProtectionPurposeStormdraininletprotectionpreventscoarsesedimentfromenteringdrainagesystemspriortopermanentstabilizationofthedisturbedarea.ConditionsofUseUsestormdraininletprotectionatinletsthatareoperationalbeforepermanentstabilizationofthedisturbeddrainagearea.Provideprotectionforallstormdraininletsdownslopeandwithin500feetofadisturbedorconstructionarea,unlessconveyingrunoffenteringcatchbasinstoasedimentpondortrap.Alsoconsiderinletprotectionforlawnandyarddrainsonnewhomeconstruction.Thesesmallandnumerousdrainscoupledwithlackofguttersinnewhomeconstructioncanaddsignificantamountsofsedimentintotheroofdrainsystem.Ifpossibledelayinstallinglawnandyarddrainsuntiljustbeforelandscapingorcapthesedrainstopreventsedimentfromenteringthesystemuntilcompletionoflandscaping.Provide18-inchesofsodaroundeachfinishedlawnandyarddrain.Table4.2.2listsseveraloptionsforinletprotection.Allofthemethodsforstormdraininletprotectiontendtoplugandrequireahighfrequencyofmaintenance.Limitdrainageareastooneacreorless.Possiblyprovideemergencyoverflowswithadditionalend-of-pipetreatmentwherestorrnwaterpondingwouldcauseahazard.olumeConstructionStormwaterPollutionPreentioizuust2012 Table4.2.2StormDrainInletProtectionApplicableforTypeofInletEmergencyPaved!EarthenProtectionOverflowSurfacesConditionsofUseDropInletProtectionExcavateddropinletYes,EarthenApplicableforheavyflows.Easyprotectiontemporarytomaintain.LargeareafloodingwillRequirement:30’X30’/acreoccurBlockandgraveldropYesPavedorEarthenApplicableforheavyconcentratedinletprotectionflows.Willnotpond.GravelandwiredropNoApplicableforheavyconcentratedinletprotectionflows.Willpond.Canwithstandtraffic.CatchbasinfiltersYesPavedorEarthenFrequentmaintenancerequired.CurbInletProtectionCurbinletprotectionSmallcapacityPavedUsedforsturdy,morecompactwithawoodenweiroverflowinstallation.BlockandgravelcurbYesPavedSturdy,butlimitedfiltration.inletprotectionCulvertInletProtectionCulvertinletsediment18monthexpectedlife.trapDesignandcaateDronietProtection-AnexcavatedimpoundmentaroundtheInstallatloitstormdrain.SedimentsettlesoutofthestorrnwaterpriortoenteringtheSpecificationsstormdrain..Provideadepthof1-2ftasmeasuredfromthecrestoftheinletstructure..Slopesidesofexcavationnosteeperthan2H:1V..Minimumvolumeofexcavation35cubicyards..Shapebasintofitsitewithlongestdimensionorientedtowardthelongestinflowarea..Installprovisionsfordrainingtopreventstandingwaterproblems..Cleartheareaofalldebris..Gradetheapproachtotheinletuniformly..Drillweepholesintothesideoftheinlet..Protectweepholeswithscreenwireandwashedaggregate..Sealweepholeswhenremovingstructureandstabilizingarea.olumeConstructionStor,ni’vaterPollutionPreentionuust20120 .Buildatemporarydike,ifnecessary,tothedownslopesideofthestructtiretopreventbypassflow.lotanGraelliter-Abarrierformedaroundthestormdraininletwithstandardconcreteblocksandgravel.SeeFigure4.28..Provideaheightof1to2feetaboveinlet..Recessthefirstrow2-inchesintothegroundforstability..Supportsubsequentcoursesbyplacinga2x4throughtheblockopening..Donotusemortar..Laysomeblocksinthebottomrowontheirsidefordewateringthepool..Placehardwareclothorcomparablewiremeshwith¼-inchopeningsoverallblockopenings..Placegraveijustbelowthetopofblocksonslopesof2H:1Vorflatter..Analternativedesignisagraveldonut..Provideaninletslopeof3H:1V..Provideanoutletslopeof2H:IV.aProvideal-footwidelevelstoneareabetweenthestructureandtheinlet.aUseinletslopestones3inchesindiameterorlarger.aUsegravel/2-to3/4-inchataminimumthicknessof1-footfortheoutletslope.oltimeConstructionStorrnwaterPollutionPreentionuust20121 uo-isnnttoiuaa1Vc4UUolautlilo•(issoou!qSWJOd!JsUOutqIOWJiSdILflSoqdrIJAO•aJrnoniTsP-’Joapisqoipuoqooj-ijomnairniw1?SUXal!MOsplu!doipioqswatioijj1ttt:iouiunqipusoiprn-gj‘;oai.toooj-qi{ipiAoiJ•3wJtosJ1O3sfl•suudOq3u!?/q5jJJtMqtuudrno3ioqopsnAOflJAOUpJAoJdousoprnpn.issiqiiujodo:oiIAOpwidJou.rnqPAJv-taqSdatiuvpvtJajfAJ9PUBN0I89t’ain6j.irn3flh1sqiJoapisdosuopqiuo&inssuq(uwipi(rniodwrotufThussucL(qwoijjjoutuUAJdodost;opuottpunoiopqtt’qisntu(iqiq&upuod)aimotusipjodoq;lelu!doipojuooeipe8Z!SjuefoJnsjouseqe)8A3X3(%9U1flssaj)seeiea6eu!eip8A81Aieeu‘jwsiojpesneqoeiesieweqiuewfpes4euIdoi•:seloN\Ijeudoa!eH6ulpuod\MO,jJAOI!P10U8eAeJQJq1eI!d—NDoIaoieiouooJoueaoseJ!MV-VuojoestoCc:oaoccsoreciir-c:Doc--_-QCII!INOES?GbO\dr)QQcYooC)\_1:‘N0018ejeiouot1Uüüuuuu[II\/Q°soRQc;cz’eI1W:5UnILibo__LiNI‘‘o5o6?NoQpc-MO!AUId .Placecoarseaggregateoverthewiremesh..Provideatleasta12-inchdepthofgravelovertheentireinletopeningandextendatleast18-inchesonallsides.Catebasinliters—Useinsertsdesignedbymanufacturersforconstructionsites.Thelimitedsedimentstoragecapacityincreasestheamountofinspectionandmaintenancerequired.whichmaybedailyforheavysedimentloads.Toreducemaintenancerequirementscombineacatchbasinfilterwithanothertypeofinletprotection.Thistypeofinletprotectionprovidesflowbypasswithoutoverflowandthereforemaybeabettermethodforinletslocatedalongactiverights-of-way..Provides5cubicfeetofstorage..Requiresdewateringprovisions..Providesahigh-flowbypassthatwillnotclogundernormaluseataconstnictionsite..Insertthecatchbasinfilterinthecatchbasinjustbelowthegrating.CurbizletProtectionwitooeneir—Barrierformedaroundacurbinletwithawoodenframeandgravel..Usewiremeshwith1/2-inchopenings..Useextrastrengthfiltercloth..Constructaframe..Attachthewireandfilterfabrictotheframe..Pilecoarsewashedaggregateagainstwire/fabric..Placeweightonframeanchors.bcanGraelCurbnietProtection—Barrierformedaroundacurbinletwithconcreteblocksandgravel.SeeFigure4.2.9..Usewiremeshwith1/2-inchopenings..Placetwoconcreteblocksontheirsidesabuttingthecurbateithersideoftheinletopening.Thesearespacerblocks..Placea2x4studthroughtheouterholesofeachspacerblocktoalignthefrontblocks..Placeblocksontheirsidesacrossthefrontoftheinletandabuttingthespacerblocks..Placewiremeshovertheoutsideverticalface..Pilecoarseaggregateagainstthewiretothetopofthebarrier.CurbanGutterSeimentarrier—Sandbagorrockberm(riprapandaggregate)3feethighand3feetwideinahorseshoeshape.SeeFigure4.2.10.olumeConstructionStormwaterPollutionPreentionuust2012 .Constructahorseshoeshapedberm.facedwithcoarseaggregateifusingriprap.3feethighand3feetwide.atleast2feetfromtheinlet..Constructahorseshoeshapedsedimentationtrapontheoutsideofthebermsizedtosedimenttrapstandardsforprotectingaculvertinlet.Maintenance.Inspectcatchbasinfiltersfrequently,especiallyafterstormevents.StaiidardsCleanandreplacecloggedinserts.Forsystemswithcloggedstonefilters:pullawaythestonesfromtheinletandcleanorreplace.Analternativeapproachwouldbetousethecloggedstoneasfillandputfreshstonearoundtheinlet..Donotwashsedimentintostormdrainswhilecleaning.Spreadallexcavatedmaterialevenl.yoverthesurroundinglandareaorstockpileandstabilizeasappropriate.ApprovedasEcologyhasapprovedproductsasabletomeettherequirementsofBMPEqttivaleiitC220.TheproductsdidnotpassthroughtheTechnologyAssessmentProtocol—Ecology(TAPE)process.Localjurisdictionsmaychoosenottoacceptthisproductapprovedasequivalent,ormayrequireadditionaltestingpriortoconsiderationforlocaluse.TheproductsareavailableforreviewonEcology’swebsiteathttp://www.ecy.wa.gov/prograrns/wq/stormwater/newtech/equivalent.htmlolumeConstructionStorrnwaterPollutionFreentio;iuust2012 PlanViewNOTES:I.Useblockandgraveltypesedimentbarrierwhencurbinletislocatedingentlyslopingstreetsegment,wherewatercanpondandallowsedimenttoseparatefromrunoff.2.Barriershallallowforoverflowfromseverestormevent.3.Inspectbarriersandremovesedimentaftereachstormevent.Sedimentandgravelmustberemovedfromthetraveledwayimmediately.Figure4.2.9—BlockandGravelCurbInletProtectionBackofSidewalkACatchBasinBackofCurb2x4WoodStudConcreteBlockSectionA-A(20mm)¾”DrainGravel(20mm)BlockBlockWireScreenorFilterFabricCurbInlet(100x50limberStud)CatchBasinolumeConstructionStornn%’aterPollutionPreentionuust2012 PlanViewBackofSidewalkNOTES:1.Placecurbtypesedimentbafflersongentlyslopingstreetsegments,wherewatercanpondandallowsedimenttoseparatefromrunoff.2.Sandbagsofeitherburlaporwoven‘geotextile’fabric,arefilledwithgravel,layeredandpackedtightly.3.Leaveaonesandbaggapinthetoprowtoprovideaspilwayforoverflow.4.Inspectbarriersandremovesedimentaftereachstormevent.Sedimentandgravelmustberemovedfromthetraveledwayimmediately.Figure4.2.10—CurbandGutterBarrierBurlapSackstoCatchBasinCurbInletBackofCurbGravelFilledSandbagsStackedTightlyolumeConstructionStornnvaterPollutionPreentionUust2012 BMPC231:BrushBarrierPItIi)OSeConditionsofUseDesignaiidInstallatlo,;Specificatio;tsPJai;ztenanceStandardsThepurposeofbrushbarriersistoreducethetransportofcoarsesedimentfromaconstructionsitebyprovidingatemporaryphysicalbafriertosedimentandreducingtherunoffvelocitiesofoverlandflow..Brushbarriersmaybeuseddownslopeofalldisturbedareasoflessthanone-quarteracre..Brushbarriersarenotintendedtotreatconcentratedflows.noraretheyintendedtotreatsubstantialamountsofoverlandflow.Anyconcentratedflowsmustbeconveyedthroughthedrainagesystemtoasedimentpond.Theonlycircumstanceinwhichoverlandflowcanbetreatedsolelybyabrushbarrier,ratherthanbyasedimentpond,iswhentheareadrainingtothebarrierissmall..Brushbarriersshouldonlybeinstalledoncontours..Height2feet(minimum)to5feet(maximum)..Width5feetatbase(minimum)to15feet(maximum)..Filterfabric(geotextile)maybeanchoredoverthebrushbermtoenhancethefiltrationabilityofthebarrier.Ten-ounceburlapisanadequatealternativetofilterfabric..Chippedsitevegetation,compostedmulch,orwood-basedmulch(hogfuel)canbeusedtoconstructbrushbarriers..A100percentbiodegradableinstallationcanbeconstructedusing10-ounceburlapheldinplacebywoodenstakes.Figure4.2.11depictsatypicalbrushbarrier..Thereshallbenosignsoferosionorconcentratedrunoffunderoraroundthebarrier.Ifconcentratedflowsarebypassingthebarrier,itmustbeexpandedoraugmentedbytoed-infilterfabric..Thedimensionsofthebarriermustbemaintained.Figure4.2.11—BrushBarrierIfrequired,drapefilterfabricoverbrushandsecurein4”x4”mm.trenchwithcompactedbackfill.Anchordownhilledgeoffilterfabricwithstakes,sandbags,orequivalent.Mm.5’widebwshbarrierwithmax.6”diameterwoodydebris.Alternativelytopsoilstrippingsmaybeusedtoformthebarrier.olumeConstructionStormwaterPollutionFreentionuust2012 BMPC232:GravelFilterBermP1111)OSCAgravelfilterbermisconstructedonrights-of-wayortrafficareaswithin•aconstructionsitetoretainsedimentbyusingafilterbermofgravelor•:crushedrock.‘ConditionsofUseWhereatemporarymeasureisneededtoretainsedimentfromrights-of-wayorintrafficareasonconstructionsites.Designaizd•Bermmaterialshallbe3/4to3inchesinsize,washedwell-gradegravelInstallationorcrushedrockwithlessthan5percentfines.Specifications..•Spacingofberrns:—Every300feetonslopeslessthan5percent—Every200feetonslopesbetween5percentand10percent—Every100feetonslopesgreaterthan10percent•Bermdimensions:—1foothighwith3H:lVsideslopes—8linearfeetper1cfsrunoffbasedonthe10-year,24-hourdesignstonnMaintenance•Regularinspectionisrequired.SedimentshallberemovedandfilterStandardsmaterialreplacedasneeded.BMPC233:SiltFencePuiposeUseofasiltfencereducesthetransportofcoarsesedimentfromaconstructionsitebyprovidingatemporaryphysicalbarriertosedimentandreducingtherunoffvelocitiesofoverlandflow.SeeFigure4.2.12fordetailsonsiltfenceconstruction.ConditionsofUseSiltfencemaybeuseddownslopeofalldisturbedareas.•Siftfenceshallpreventsoilcarriedbyrunoffwaterfromgoingbeneath,through,oroverthetopofthesiltfence,butshallallowthewatertopassthroughthefence.•Siltfenceisnotintendedtotreatconcentratedflows,norisitintendedtotreatsubstantialamountsofoverlandflow.Conveyanyconcentratedflowsthroughthedrainagesystemtoasedimentpond.•DonotconstructsiltfencesinstreamsoruseinV-shapedditches.Siltfencesdonotprovideanadequatemethodofsiltcontrolforanythingdeeperthansheetoroverlandflow.olumeConstructionStorrnwaterPollutionPreentionitust2012 Figure4.2.12—SiltFenceDesignandInstallationSpecifications.UseincombinationwithsedimentbasinsorotherBMPs..Maximumslopesteepness(normal(jerpendicular)tofenceline)1H:1V..MaximumsheetoroverlandflowpathlengthtothefenceofI00feet..Donotallowflowsgreaterthan0.5cfs..Thegeotextileusedshallmeetthefollowingstandards.Allgeotextilepropertieslistedbelowareminimumaveragerollvalues(i.e.,thetestresultforanysampledrollinalotshallmeetorexceedthevaluesshowninTable4.2.3):Table4.2.3GeotextileStandardsPolymericMeshAOS0.60mmmaximumforslitfilmwoven(#30sieve).0.30(ASTMD4751)mmmaximumforallothergeotextiletypes(#50sieve).0.15mmminimumforallfabrictypes(#100sieve).WaterPermittivity0.O2secTminimum(ASTMD4491)GrabTensileStrength180lbs.Minimumforextrastrengthfabric.(ASTMD4632)..100lbsminimumforstandardstrengthfabric.GrabTensileStrength30%maximum(ASTMD4632)UltravioletResistance70%minimum(ASTMD4355).Supportstandardstrengthfabricswithwiremesh,chickenwire,2-inchx2-inchwire,safetyfence,orjutemeshtoincreasethestrengthoftheJointsinNierfabricshallbespiced31pos1sUses1apeswireri19soC1LHVEiItDflt10attachfahnctoposts2!x2bV14Gwin:oreqLiIvaent.ifStalidatCistiengthfabricusedFl1rtabnc3%A——6max—-c’JIPostspacingmaybeincreasedto8ifwirebackingisusedMIflImUm4x4trench/tA\BackfilltrenchwithnativeSoIlor34-1.5’washedgravelEc’JI2x2woodposts,steellencepostsorequivalentolumeConstructionStormwaterPollutionPreentionuust2012 fabric.Siltfencematerialsareavailablethathavesyntheticmeshbackingattached.Filterfabricmaterialshallcontainultravioletrayinhibitorsandstabilizerstoprovideaminimumofsixmonthsofexpectedusableconstructionlifeatatemperaturerangeof0°F.to120°F.One-hundredpercentbiodegradablesiltfenceisavailablethatisstrong,longlasting,andcanbeleftinplaceaftertheprojectiscompleted,ifpermittedbylocalregulations.RefertoFigure4.2.12forstandardsiltfencedetails.IncludethefollowingstandardNotesforsiltfenceonconstructionplansandspecifications:1.ThecontractorshallinstallandmaintaintemporarysiltfencesatthelocationsshowninthePlans.2.Constructsiltfencesinareasofclearing,grading,ordrainagepriortostartingthoseactivities.3.Thesiltfenceshallhavea2-feetmm.anda2i4-feetmax.heightabovetheoriginalgroundsurface.4.Thefilterfabricshallbesewntogetheratthepointofmanufacturetoformfilterfabriclengthsasrequired.Locateallsewnseamsatsupportposts.Alternatively,twosectionsofsiltfencecanbeoverlapped,providedtheContractorcandemonstrate,tothesatisfactionoftheEngineer,thattheoverlapislongenoughandthattheadjacentfencesectionsarecloseenoughtogethertopreventsiltladenwaterfromescapingthroughthefenceattheoverlap.5.Attachthefilterfabricontheup-slopesideofthepostsandsecurewithstaples,wire,orinaccordancewiththemanufacturer’srecommendations.Attachthefilterfabrictothepostsinamannerthatreducesthepotentialfortearing.6.Supportthefilterfabricwithwireorplasticmesh,dependentonthepropertiesofthegeotextileselectedforuse.Ifwireorplasticmeshisused,fastenthemeshsecurelytotheup-slopesideofthepostswiththefilterfabricup-slopeofthemesh.7.Meshsupport,ifused,shallconsistofsteelwirewithamaximummeshspacingof2-inches,oraprefabricatedpolymericmesh.Thestrengthofthewireorpolymericmeshshallbeequivalenttoorgreaterthan180lbs.grabtensilestrength.Thepolymericmeshmustbeasresistanttothesamelevelofultravioletradiationasthefilterfabricitsupports.8.Burythebottomofthefilterfabric4-inchesmm.belowthegroundsurface.Backfillandtampsoilinplaceovertheburiedportionofthefilterfabric,sothatnoflowcanpassbeneaththefenceandohiineConstructiol?Stornn4.’aterFollutiol?Preentionuiist20120 scouringcannotoccur.Whenwireorpolymericback-upsupportmeshisused,thewireorpolymericmeshshallextendintotheground3-inchesmm.9.Driveorplacethefencepostsintotheground18-inchesmm.AI2—inchmm.depthisallowediftopsoilorothersoftsubgradesoilisnotpresentand18-mnchescannotbereached.Increasefencepostu-un.depthsby6inchesifthefenceislocatedonslopesof3H:1Vorsteeperandtheslopeisperpendiculartothefence.ifrequiredpostdepthscannotbeobtained,thepostsshallbeadequatelysecuredbybracingorguyingtopreventoverturningofthefenceduetosedimentloading.10.Usewood,steelorequivalentposts.Thespacingofthesupportpostsshallbeamaximumof6-feet.Postsshallconsistofeither:.Wood‘jthdimensionsof2-inchesby2-incheswidemm.anda3-feetmm.length.Woodpostsshallbefreeofdefectssuchasknots,splits,orgouges..No.6steelrebarorlarger..ASTMA120steelpipewithaminimumdiameterof1-inch..U,T,L,orCshapesteelpostswithaminimumweightof1.35lbs./ft..Othersteelpostshavingequivalentstrengthandbendingresistancetothepostsizeslistedabove.11.Locatesiltfencesoncontourasmuchaspossible,exceptattheendsofthefence,wherethefenceshallbeturneduphillsuchthatthesiltfencecapturestherunoffwaterandpreventswaterfromflowingaroundtheendofthefence.i2.Ifthefencemustcrosscontours,withtheexceptionoftheendsofthefence,placegravelcheckdamsperpendiculartothebackofthefencetominimizeconcentratedflowanderosion.Theslopeofthefencelinewherecontoursmustbecrossedshallnotbesteeperthan3H:1V..Gravelcheckdamsshallbeapproximately1-footdeepatthebackofthefence.Gravelcheckdamsshallbecontinuedperpendiculartothefenceatthesameelevationuntilthetopofthecheckdarninterceptsthegroundsurfacebehindthefence..Gravelcheckdamsshallconsistofcrushedsurfacingbasecourse,gravelbackfillforwalls,orshoulderballast.Gravelcheckdamsshallbelocatedevery10feetalongthefencewherethefencemustcrosscontours.Refertofigure4.2.13forslicingmethoddetails.Siltfenceinstallationusingtheslicingmethodspecifications:oltimeConstructionStol7nwaterPollutionPreentionuust20121 1.Thebaseofbothendpostsmustbeatleast2-to4-inchesabovethetopofthefilterfabriconthemiddle1)OStsforditchcheckstodrainproperly.Useahandlevelorstringlevel,ifnecessaiy,tomarkbasepointsbeforeinstallation.2.Installposts3-to4-feetapartincriticalretentionareasand6-to7-feetapartinstandardapplications.3.Installposts24-inchesdeeponthedownstreamsideofthesiltfence,andascloseaspossibletothefilterfabric,enablingpoststosupportthefilterfabricfromupstreamwaterpressure.4.Installpostswiththenipplesfacingawayfromthefilterfabric.5.Attachthefilterfabrictoeachpostwiththreeties,allspacedwithinthetop8-inchesofthefilterfabric.Attacheachtiediagonally45degreesthroughthefilterfabric,witheachpunctureatleast1-inchverticallyapart.Eachtieshouldbepositionedtohangonapostnipplewhentighteningtopreventsagging.6.Wrapapproximately6-inchesoffabricaroundtheendpostsandsecurewith3ties.7.Nomorethan24-inchesofa36-inchfilterfabricisallowedabovegroundlevel.Compactthesoilimmediatelynexttothefilterfabricwiththefrontwheelofthetractor,skidsteer,orrollerexertingatleast60poundspersquareinch.Compacttheupstreamsidefirstandtheneachsidetwiceforatotaloffourtrips.Checkandcorrectthesiltfenceinstallationforanydeviationbeforecompaction.Useaflat-bladedshoveltotuckfabricdeeperintothegroundifnecessary.olumeConstructionStormwaterPollutionFreentionuust20122 AttachfabricftupstreamsideofpostFLOW—.Ddv.oww.schaid.ofsiftfence2to4tImeswithdeviceexerting60p..i.orreeftrPOSTSPACING:7•max.onop.nruns4•max.onpoolingar.ssPOSTDEPTh:AsmuchbelowgroundCefabricabovegroundRolofsfenceSlchgblade(18mmwidth)Fabiicaboveigou•200-300mmI/7’Vib(atOfyplowisnotacceptablebecauseofhodzontalcompactionFigure4.213—SiltFenceInstallationbySlicingMethodPoststaedaftercompactionMaintenanceStandards.Repairanydamageimmediately.aInterceptandconveyallevidentconcentratedflowsuphillofthesiltfencetoasedimentpond..Checktheuphillsideofthefenceforsignsofthefencecloggingandactingasabarriertoflowandthencausingchannelizationofflowsparalleltothefence.Ifthisoccurs,replacethefenceorremovethetrappedsediment.Pendingheightmax.24100%compsctionDiagonalauachmerfdoubins*e8AflAHMENTDEtAIlS:CGathertebdcofposts.IneededCUtilizetiseefesperpost,oIlwithintop8oftabric.CPositioneachliecIlagonaIly,puncttaingholesveiticalyarrIlnlmLmnof1opalS.CHangeachtieonapostnippleandtightensecirely.Usecable(SOIbsorsoêwie.Nomorethan24°ofa36fabricisallowedaboveground.4—OpprationSUtFenceIHodwnt&ctigd(76mmwid‘‘%:‘‘;N’‘‘‘t“‘•‘CompletedkistalationolumeConstructionStormwaterPollutionPreentionuus!2012 .Removesedimentdepositswhenthedepositreachesapproximatelyone-thirdtheheightofthesiltfence,orinstallasecondsiftfence..Replacefilterfabricthathasdeterioratedduetoultravioletbreakdown.BMPC234:VegetatedStripPuiposeVegetatedstripsreducethetransportofcoarsesedimentfromaconstructionsitebyprovidingatemporaryphysicalbarriertosedimentandreducingtherunoffvelocitiesofoverlandflow.ConditionsofUse.Vegetatedstripsmaybeuseddownslopeofalldisturbedareas..Vegetatedstripsarenotintendedtotreatconcentratedflows,noraretheyintendedtotreatsubstantialamountsofoverlandflow.Anyconcentratedflowsmustbeconveyedthroughthedrainagesystemtoasedimentpond.Theonlycircumstanceinwhichoverlandflowcanbetreatedsolelybyastrip,ratherthanbyasedimentpond,iswhenthefollowingcriteriaaremet(seeTable4.2.4):Table4.2.4ContributingDrainageAreaforVegetatedStripsAraConriinAraConriinaraMaConriinaraSoPrnSoarafoaLn1.5H:1Vorflatter67%orflatter100feet2H:1Vorflatter50%orflatter115feet4H:lVorflatter25%orflatter150feet6H:1Vorflatter16.7%orflatter200feet1OH:1Vorflatter10%orflatter250feetDesignaiid•Thevegetatedstripshallconsistofaminimumofa25-footfiowpathInstallationlengthcontinuousstripofdensevegetationwithtopsoil.Grass-Specificationscovered,landscapedareasaregenerallynotadequatebecausethevolumeofsedimentoverwhelmsthegrass.Ideally,vegetatedstripsshallconsistofundisturbednativegrowthwithawell-developedsoilthatallowsforinfiltrationofrunoff.•Theslopewithinthestripshallnotexceed4H:lV.•Theuphillboundaryofthevegetatedstripshallbedelineatedwithclearinglimits.Maintenance•AnyareasdamagedbyerosionorconstructionactivityshallbeStandardsseededimmediatelyandprotectedbymulch.•Ifmorethan5feetoftheoriginalvegetatedstripwidthhashadvegetationremovedorisbeingeroded,sodmustbeinstalled.•Ifthereareindicationsthatconcentratedflowsaretravelingacrossthebuffer,surfacewatercontrolsmustbeinstalledtoreducetheflowsolumeConstructionStorrnwaterPollutionfreentionuust2012 enteringthebuffer,oradditionalperimeterprotectionmustbeinstalled.BMPC235:WattlesPuiposeWattlesaretemporaryerosionandsedimentcontrolbarriersconsistingofstraw,compost,orothermaterialthatiswrappedinbiodegradabletubularplasticorsimilarencasingmaterial.Theyreducethevelocityandcanspreadtheflowofnilandsheetrunoff,andcancaptureandretainsediment.Wattlesaretypically8to10inchesindiameterand25to30feetinlength.Wattlesareplacedinshallowtrenchesandstakedalongthecontourofdisturbedornewlyconstructedslopes.SeeFigure4.2.14fortypicalconstructiondetails.WSDOTStandardPlan1-30.30-00alsoprovidesinformationonWattles(http://www.wsdot.wa.gov/Design/Standards/Plans.htm#Sectionl)ConditionsofUse•Usewattles:.Indisturbedareasthatrequireimmediateerosionprotection..Onexposedsoilsduringtheperiodofshortconstructiondelays,oroverwintermonths..Onslopesrequiringstabilizationuntilpermanentvegetationcanbeestablished..Thematerialuseddictatestheeffectivenessperiodofthewattle.Generally,Wattlesaretypicallyeffectiveforonetotwoseasons..Preventrillingbeneathwattlesbyproperlyentrenchingandabuttingwattlestogethertopreventwaterfrompassingbetweenthem.DesignCriteria•Installwattlesperpendiculartotheflowdirectionandparalleltotheslopecontour.•Narrowtrenchesshouldbedugacrosstheslopeoncontourtoadepthof3-to5-inchesonclaysoilsandsoilswithgradualslopes.Onloosesoils,steepslopes,andareaswithhighrainfall,thetrenchesshouldbedugtoadepthof5-to7-inches,or112to2/3ofthethicknessofthewattle.•Startbuildingtrenchesandinstallingwattlesfiornthebaseoftheslopeandworkup.Spreadexcavatedmaterialevenlyalongtheuphillslopeandcompactedusinghandtampingorothermethods.•Constructtrenchesatintervalsof10-to25-feetdependingonthesteepnessoftheslope,soiltype,andrainfall.Thesteepertheslopetheclosertogetherthetrenches.•Installthewafflessnuglyintothetrenchesandabuttightlyendtoend.Donotoverlaptheends.•Installstakesateachendofthewattle,andat4-footcentersalongentirelengthofwattle.ohnneConstructionStornnvaterPollutionFreentioniiust2012 .Ifrequired.installpilotholesforthestakesusingastraightbartodriveho’esthroughthewattleandintothesoil..Woodenstakesshouldbeapproximately3/4x3/4x24inchesmm.Willowcuttingsor3/8-inchrebarcanalsobeusedforstakes..Stakesshouldbedriventhroughthemiddleofthewattle,leaving2to3inchesofthestakeprotrudingabovethewattle.Mainteiiaiice•WattlesmayrequiremaintenancetoensuretheyareincontactwithStandardssoilandthoroughlyentrenched,especiallyaftersignificantrainfallonsteepsandysoils.oltimeConstructionStorrnwaterPollutionFreentionuust2012 StrawRollsMustBePlacedAlongSlopeContoursN/3”-5”(75-125mm))\)‘2\<\2\228”-1O”DlA.(200-250mm)/1/1”Xi”Stake(25x25mm)_3,-4,\(1.2m)“S10-25’(3-8m)Sediment,organicmatter,andnativeseedsarecapturedbehindtherolls.SpacingDependsonSoilTypeandSlopeSteepnessLivenottoscaleNOTE:1.Strawrollinstallationrequirestheplacementandsecurestakingoftherollinatrench,3-5”(75-125mm)deep,dugoncontour.runoffmustnotbeallowedtorununderoraroundroll.Figure4.214—Wattlesol;tmeConstructionStormwaterPollutionPreentionUust2012 .Inspecttheslopeaftersignificantstormsandrepairanyareaswhereatt1esarenottightlyabuttedorwaterhasscouredbeneaththewattles.ApprovedasEcologyhasapprovedproductsasabletomeettherequirementsofBMPEquivctlentC235.TheproductsdidnotpassthroughtheTecimologyAssessmentProtocol—Ecology(TAPE)process.Localjurisdictionsmaychoosenottoacceptthisproductapprovedasequivalent,ormayrequireadditionaltestingpriortoconsiderationforlocaluse.TheproductsareavailableforreviewonEcology’swebsiteathttp://www.ecy.wa.gov/programs/wq/storrnwater/newtech/eguivalent.htrnlBMPC236:VegetativeFiltrationPurposeVegetativefiltrationmaybeusedinconjunctionwithBMPC241TemporarySedimentPonds,BMPC206LevelSpreaderandapumpingsystemwithsurfaceintaketoimproveturbiditylevelsofstoniiwaterdischargesbyfilteringthroughexistingvegetationwhereundisturbedforestfloordufflayerorestablishedlawnwiththatchlayerarepresent.VegetativeFiltrationcanalsobeusedtoinfiltratedewateringwastefromfoundations,vaults,andtrenchesaslongasrunoffdoesnotoccur.ConditionsofUse•Foreveryfiveacreofdisturbedsoiluseoneacreofgrassfield,farmpasture,orwoodedarea.Reduceorincreasethisareadependingonprojectsize,groundwatertableheight,andothersiteconditions..Wetlandsshallnotbeusedforfiltration..DonotusethisBMPinareaswithahighgroundwatertable,orinareasthatwillhaveahighseasonalgroundwatertableduringtheuseofthisBMP.•ThisBMPmaybelesseffectiveonsoilsthatpreventtheinfiltrationofthewater,suchashardtill.•UsingothereffectivesourcecontrolmeasuresthroughoutaconstructionsitewillpreventthegenerationofadditionalhighlyturbidwaterandmayreducethetimeperiodorareaneedforthisBMP.•Stopdistributingwaterintothevegetatedareaifstandingwaterorerosionresults.DesignCriteria•Findlandadjacenttotheprojectthathasavegetatedfield,preferablyafarmfield,orwoodedarea.•Iftheprojectsitedoesnotcontainenoughvegetatedfieldareaconsiderobtainingpermissionfromadjacentlandowners(especiallyforfarmfields).•Installapumpanddownstreamdistributionmanifolddependingontheprojectsize.Generally,themaindistributionlineshouldreach100to200-feetlong(manylargeprojects,orprojectsontightsoil,willohtineConstructionStorniwaterPollutionFreentionuust2012 requiresystemsthatreachseveralthousandfeetlongwithnumerousbranchlinesoffofthemaindistributionline)..Themanifoldshouldhaveseveralvalves.allowingforcontroloverthedistributionareainthefield..Installseveralbranchesof4”schedule20,swaged-fitcommonseptictight-linedsewerline.or6”firehose,whichcanconveytheturbidwaterouttovarioussectionsofthefield.SeeFigure4.2.15..Determinethebranchlengthbasedonthefieldareageographyandnumberofbranches.Typically,branchesstretchfrom200-feettoseveralthousandfeet.Always,laybranchesoncontourwiththeslope..Onunevenground,sprinklersperformwell.Spacesprinklerheadssothatspraypatternsdonotoverlap..Onrelativelyevensurfaces,alevelspreaderusing4-inchperforatedpipemaybeusedasanalternativeoptiontothesprinklerheadsetup.Installdrainpipeatthehighestpointonthefieldandatvariouslowerelevationstoensurefullcoverageofthefiltrationarea.Pipeshouldbeplacewiththeholesuptoallowforagentleweepingofstormwaterevenlyoutallholes.Levelingthepipebystakingandusingsandbagsmayberequired..Topreventtheoversaturationofthefieldarea,rotatetheuseofbranchesorsprayheads.Dothisasneededbasedonmonitoringthesprayfield..Monitorthesprayfieldonadailybasistoensurethatoversaturationofanyportionofthefielddoesn’toccuratanytime.Thepresenceofstandingpuddlesofwaterorcreationofconcentratedflowsvisuallysignifythatoversaturationofthefieldhasoccurred..Sincetheoperatorishandlingcontaminatedwater,physicallymonitorthevegetatedsprayfieldallthewaydowntothenearestsurfacewater,orfurthestsprayarea,toensurethatthewaterhasnotcausedoverlandorconcentratedflows,andhasnotcreatederosionaroundthespraynozzle..Monitoringusuallyneedstotakeplace3-5timesperdaytoensuresheet-flowintostatewaters.Donotexceedwaterqualitystandardsforturbidity..Ecologystronglyrecommendsthataseparateinspectionlogbedeveloped,maintainedandkeptwiththeexistingsitelogbooktoaidtheoperatorconductinginspections.Thisseparate“FieldfiltrationLogbook”canalsoaidthefacilityindemonstratingcompliancewithpermitconditions.Maiiitenance•Inspectthespraynozzlesdaily,ataminimum,forleaksandpluggingStandardsfromsedimentparticles.olumeConstructionStorrnwaterPollutionPreentionuust20]2 .Iferosion,concentratedflows,oroversaturationofthefieldoccurs,rotatetheuseofbranchesorsprayheadsormovethebranchestoanewfieldlocation..Checkallbranchesandthemanifoldforunintendedleaks.FlowpathGuidelinesforVegetativeFiltrationAverageSlopeAverageArea%SlopeEstimatedFlowpathLength(ft)1.5H:1V67%2502H:1V50%2004H:1V25%1506H:1V16.7%1151OH:1V10%100oltimeConstructionStormwaterPollutionPreentionuust2012Figure4.2.15—ManifoldandBrachesinawooded,vegetatedsprayfield100 BMPC240:SedimentTrapPitiposeAsedimenttrapisasmalltemporarypondingareawithagraveloutletusedtocollectandstoresedimentfromsitesclearedand/orgradedduringconstruction.Sedimenttraps,alongwithotherperimetercontrols,shallbeinstalledbeforeanylanddisturbancetakesplaceinthedrainagearea.Coi;ditionsofUsePriortoleavingaconstructionsite,storrnwaterrunoffmustpassthroughasedimentpondortraporotherappropriatesedimentremovalbestmanagementpractice.Non-engineeredsedimenttrapsmaybeusedon-sitepriortoanengineeredsedimenttraporsedimentpondtoprovideadditionalsedimentremovalcapacity.Itisintendedforuseonsiteswherethetributarydrainageareaislessthan3acres,withnounusualdrainagefeatures,andaprojectedbuild-outtimeofsixmonthsorless.Thesedimenttrapisatemporarymeasure(withadesignlifeofapproximately6months)andshallbemaintaineduntilthesiteareaispermanentlyprotectedagainsterosionbyvegetationand/orstructures.Sedimenttrapsandpondsareonlyeffectiveinremovingsedimentdowntoaboutthemediumsiltsizefraction.Runoffwithsedimentoffinergrades(finesiltandclay)willpassthroughuntreated,emphasizingtheneedtocontrolerosiontothemaximumextentfirst.Wheneverpossible,sediment-ladenwatershallbedischargedintoon-site,relativelylevel,vegetatedareas(seeBMPC234VegetatedStrip).Thisistheonlywaytoeffectivelyremovefineparticlesfrommnoffunlesschemicaltreatmentorfiltrationisused.Thiscanbeparticularlyusefulafterinitialtreatmentinasedimenttraporpond.Theareasofreleasemustbeevaluatedonasite-by-sitebasisinordertodetermineappropriatelocationsforandmethodsofreleasingrunoff.Vegetatedwetlandsshallnotbeusedforthispurpose.frequently,itmaybepossibletopumpwaterfromthecollectionpointatthedownhillendofthesitetoanupsiopevegetatedarea.Pumpingshallonlyaugmentthetreatmentsystem,notreplaceit,becauseofthepossibilityofpurnpfailureorrunoffvolumeinexcessofpumpcapacity.Allprojectsthatareconstructingpermanentfacilitiesforrunoffquantitycontrolshouldusetherough-gradedorfinal-gradedpermanentfacilitiesfortrapsandponds.Thisincludescombinedfacilitiesandinfiltrationfacilities.Whenpermanentfacilitiesareusedastemporarysedimentationfacilities,thesurfacearearequirementofasedimenttraporpondmustbemet.Ifthesurfacearearequirementsarelargerthanthesurfaceareaofthepermanentfacility,thenthetraporpondshallbeenlargedtocomplywiththesurfacearearequirement.Thepermanentpondshallalsobedividedintotwocellsasrequiredforsedimentponds.olumeConstructionStorniwaterPollutionPreentionuust2012101 Eitherapermanentcontrolstructureorthetemporarycontrolstructure(describedinBMPC24I,TemporarySedimentPond)canbeused.ifapermanentcontrolstructureisused,itmaybeadvisabletopartiallyrestrictthelowerorificewithgraveltoincreaseresidencetimewhilestillallowingdewateringofthepond.Ashut-offvalvemaybeaddedtothecontrolstructuretoallowcompleteretentionofstormwaterinemergencysituations.Inthiscase,anemergencyoverflowweirmustbeadded.AskimmermaybeusedforthesedimenttrapoutletifapprovedbytheLocalPermittingAuthority.Designand•Seefigures4.2.16and4.2.17fordetails.Installation....•Ifperrnanentrunoffcontroltacihtiesarepartoftheproject,theySpecifications.shouldbeusedforsedimentretention.•Todeterminethesedimenttrapgeometry,firstcalculatethedesignsurfacearea(SA)ofthetrap,measuredattheinvertoftheweir.Usethefollowingequation:S(2/)where2=Designinflowbasedonthepeakdischargefromthedeveloped2-yearrunoffeventfromthecontributingdrainageareaascomputedinthehydrologicanalysis.The10-yearpeakflowshallbeusediftheprojectsize,expectedtiminganddurationofconstruction,ordownstreamconditionswarrantahigherlevelofprotection.Ifnohydrologicanalysisisrequired,theRationalMethodmaybeused.S=Thesettlingvelocityofthesoilparticleofinterest.The0.02mm(mediumsilt)particlewithanassumeddensityof2.65g/cm3hasbeenselectedastheparticleofinterestandhasasettlingvelocity()of0.00096ft/sec.S=Asafetyfactorof2toaccountfornon-idealsettling.Therefore,theequationforcomputingsurfaceareabecomes:S=2x2/0.00096Of2080squarefeetpercfsofinflowNote:Evenifperrnanentfacilitiesareused,theymuststillhaveasurfaceareathatisatleastaslargeasthatderivedfromtheabovefommia.Iftheydonot,thepondmustbeenlarged..Toaidindeterminingsedimentdepth,allsedimenttrapsshallhaveastaffgaugewithaprominentmark1-footabovethebottomofthetrap.olttmeConstructionStorrnwaterPollutionFrentionuust2012102 .Sedimenttrapsmaynotbefeasibleonutilityprojectsduetothelimitedworkspaceortheshort-termnatureofthework.Portabletanksmaybeusedinplaceofsedimenttrapsforutilityprojects....::Maintenance•Sedimentshallberemovedfromthetrapwhenitreaches1-footinStandardsdepth.•Anydamagetothepondembankrnentsorslopesshallberepaired.SurfaceareadeterminedI4Mm.attopofweir--———j\\Lc-iMmOverflow11Mm.9A\4Mm355iA••,...:fl?aPP-1.5”\2”-4”RockWashedgravel\\Note:TrapmaybeformedbybermorbyGlpartialorcompleteexcavationeoexIeDischargetostabilizedconveyance,outlet,orlevelspreaderFigure4216—CrossSectionofSedimentTrapH’6’Mm.Hcompactedbackfill‘,\4-iJ24rock-9-fl::_IIL-:::H’IzIIiHHIJEMmIdepth3/4I5Geotextile_jwashedgravelFigure4.2.17—SedimentTrapOutletolttineConstructionStorrnwaterPollutionPreentionuust201210 BMPC241:TemporarySedimentPondPurposeSedimentpondsremovesedimentfromrunofforiginatingfromdisturbedareasofthesite.Sedimentpondsarctypicallydesignedtoremovesedimentnosmallerthanmediumsilt(0.02mm).Consequently,theyusuallyreduceturbidityonlyslightly.ConditionsofUsePriortoleavingaconstructionsite,stormwaterrunoffmustpassthroughasedimentpondorotherappropriatesedimentremovalbestmanagementpractice.Asedimentpondshallbeusedwherethecontributingdrainageareais3acresormore.Pondsmustbeusedinconjunctionwitherosioncontrolpracticestoreducetheamountofsedimentflowingintothebasin.Designand•SedimentbasinsmustbeinstalledonlyonsiteswherefailureoftheInstallationstructurewouldnotresultinlossoflife,damagetohomesorSpecificationsbuildings,orinterruptionofuseorserviceofpublicroadsorutilities.Also,sedimenttrapsandpondsareattractivetochildrenandcanbeverydangerous.Compliancewithlocalordinancesregardinghealthandsafetymustbeaddressed.Iffencingofthepondisrequired,thetypeoffenceanditslocationshallbeshownontheESCplan.•Structureshavingamaximumstoragecapacityatthetopofthedarnof10acre-ft(435,600fi3)ormorearesubjecttotheWashingtonDarnSafetyRegulations(Chapter173-175WAC).•Seefigures4.2.18,4.2.19,and4.2.20fordetails.•Ifpermanentrunoffcontrolfacilitiesarepartoftheproject,theyshouldbeusedforsedimentretention.Thesurfacearearequirementsofthesedimentbasinmustbemet.Thismayrequiretemporarilyenlargingthepermanentbasintocomplywiththesurfacearearequirements.Thepermanentcontrolstructurenmstbetemporarilyreplacedwithacontrolstructurethatonlyallowswatertoleavethepondfromthesurfaceorbypumping.Thepermanentcontrolstructuremustbeinstalledafterthesiteisfullystabilized.•Useofinfiltrationfacilitiesforsedimentationbasinsduringconstructiontendstoclogthesoilsandreducetheircapacitytoinfiltrate.Ifinfiltrationfacilitiesaretobeused,thesidesandbottomofthefacilitymustonlyberoughexcavatedtoaminimumof2feetabovefinalgrade.Finalgradingoftheinfiltrationfacilityshalloccuronlywhenallcontributingdrainageareasarefullystabilized.Theinfiltrationpretreatmentfacilityshouldbefullyconstructedandusedwiththesedimentationbasintohelppreventclogging.•DeterminingPondGeometryObtainthedischargefromthehydrologiccalculationsofthepeakflowforthe2-yearrunoffevent(2).The10-yearpeakflowshallbeusedifoliimeConstructionStorimraterPollutionFreentionuust201210 theprojectsize,expectedtiminganddurationofconstruction,ordownstreamconditionswarrantahigherlevelofproteetion.ifnohydrologicanalysisisrequired,theRationalMethodmaybeused.Determinetherequiredsurfaceareaatthetopoftheriserpipewiththeequation:S=2x2!O.00096or2080squarefeetperefsofinflowSeeBMPC240formoreinformationonthederivationofthesurfaceareacalculation.Thebasicgeometryofthepondcannowbedeterminedusingthefollowingdesigncriteria:RequiredsurfaceareaSA(fromStep2above)attopofriser.Minimum3.5-footdepthfromtopofrisertobottomofpond.Maximum3H:1Vinteriorsideslopesandmaximum2H:1Vexteriorslopes.Theinteriorslopescanbeincreasedtoamaximumof2H:1Viffencingisprovidedatorabovethemaximumwatersurface.SOnefootoffreeboardbetweenthetopoftheriserandthecrestoftheemergencyspiliway.flatbottom.Minimum1-footdeepspillway.Length-to-widthratiobetween3:1and6:1.SizingofDischargeMechanisms.Theoutletforthebasinconsistsofacombinationofprincipalandemergencyspiliways.Theseoutletsmustpassthepeakrunoffexpectedfromthecontributingdrainageareafora100-yearstorm.if,duetositeconditionsandbasingeometry,aseparateemergencyspill-wayisnotfeasible,theprincipalspiliwaymustpasstheentirepeakrunoffexpectedfromthe100-yearstorm.However,anattempttoprovideaseparateemergencyspillwayshouldalwaysbemade.Therunoffcalculationsshouldbebasedonthesiteconditionsduringconstruction.Theflowthroughthedewateringorificecannotbeutilizedwhencalculatingthe100-yearstormelevationbecauseofitspotentialtobecomeclogged;therefore,availablespillwaystoragemustbeginattheprincipalspiliwayrisercrest.Theprincipalspiliwaydesignedbytheprocedurescontainedinthisstandardwillresultinsomereductioninthepeakrateofrunoff.However,theriseroutletdesignwillnotadequatelycontrolthebasindischargetothepredevelopmentdischargelimitationsasstatedinMinimumRequirement#7:flowControl.However,ifthebasinforapermanentstormwaterdetentionpondisusedforatemporaryolitmeConstructionStormwaterPollutionFreentionuust201210 sedimentationbasin,thecontrolstructureforthepern;anentpondcanbeusedtomaintainpredevelopmentdischargelimitations.Thesizeofthebasin.theexpectedlifeoftheconstructionproject,theanticipateddownstreameffectsandtheanticipatedweatherconditionsduringconstruction,shouldbeconsideredtodeterminetheneedofadditionaldischargecontrol.SeeFigure4.2.21forriserinflowcurves.Figure4.2.19—SedimentPondCrossSectionolumeConstructionStorinwaterPollutionPreentionuust201210Note:PondmaybeformedbybermorbypartialorcompleteexcavationFigure4.2.18—SedimentPondPlanViewRiserpipe(principalspillway)Crestofwithemergencspiliway6man.Widthl=H=T11Embankmentcompacted95%•fl1=iDewateringdevice\i-%:::.JerviousmaterialssuchassandshallWire-backedsiltfenceDewateringConcretebaseconveyanceoutletorstakedhaybeswrappedorifice(seeriserdetail)levelspreaderequivalentdivider PolyethylenecapProvideadequate18mm.Alternatively,metalstakes_I__Concretebausedto1-•-—axriserdia.Mm.—•Figure4.2.20—SedimentPondRiserDetailolumeConstructionStormwaterPollutionPreentionuust201210 100C00C)0C)0C)C)0.00aFigure4.2.21—RiserInflowCurves1010.1110HEADINFEET(measuredfromcrestofriser)°weirDH312°ari1ice3782D2H1120incls,DandHinfeetSlopechangeoccursatweir-orificetransitionolumeConstructionStorrnwaterPollutionPreentionuust201210 PrinIaSIaDeterminetherequireddiameterfortheprincipalspiliway(riserpipe).Thediametershallbetheminimumnecessarytopassthesite’s15-minute,10-yearflowrate.IfusingtheWesternWashingtonHydrologyModel(WWHM),Version2or3,designflowisthe10-year(1hour)flowforthedeveloped(unmitigated)site,multipliedbyafactorof1.6.UseFigure4.2.21todeterminethisdiameter(1-foot).oleernianentcontrolstuiteturemabeuseinsteaoaternorarriserErII0rf0SIaDeterminetherequiredsizeanddesignoftheemergencyoverflowspiliwayforthedeveloped100-yearpeakflowusingthemethodcontainedinVolumeIII.DanflOrifiDeterminethesizeofthedewateringorifice(s)(minimum1-inchdiameter)usingamodifiedversionofthedischargeequationforaverticalorificeandabasicequationfortheareaofacircularorifice.Determinetherequiredareaoftheorificewiththefollowingequation:—(2)500.6x3600°where=orificearea(squarefeet)S=pondsurfacearea(squarefeet)=headofwateraboveorifice(heightofriserinfeet)=dewateringtime(24hours)=accelerationofgravity(32.2feet/second2)ConverttherequiredsurfaceareatotherequireddiameterDoftheorifice:D=24xF=13.54xThevertical,perforatedtubingconnectedtothedewateñngorificemustbeatleast2incheslargerindiameterthantheorificetoimproveflowcharacteristics.Thesizeandnumberofperforationsinthetubingshouldbelargeenoughsothatthetubingdoesnotrestrictflow.Theorificeshouldcontroltheflowrate..AdditionalDesignSpecificationsThepondshallbedividedintotworoughlyequalvolumecellsbyapermeabledividerthatwillreduceturbulencewhileallowingmovementofwaterbetweencells.Thedividershallbeatleastone-halftheheightoftheriserandaminimumofonefootbelowthetopoftheriser.Wire-backed,2-to3-foothigh,extrastrengthfilterfabricsupportedbytreated4”x4”scanbeusedasadivider.Alternatively,stakedstrawbaleswrappedwithfilterfabric(geotextile)maybeused.Ifthepondismorethan6feetdeep,adifferentmechanismmustbeproposed.AriprapembankmentisoneacceptablemethodofolitmeConstructionStormwaterPollutionPreentionuus!201210 separationfordeeperponds.Otherdesignsthatsatisfytheintentofthisp1•ovisioflareallowedaslongasthedividerispermeable,structurallysound,anddesignedtopreventerosionunderoraroundthebarrier.Toaidindeterminingsedimentdepth,one-footintervalsshallbe1)romincntlymarkedontheriser.ifanembankmentofmorethan6feetisproposed,thepondmustcomplywiththecriteriacontainedinVolumeIIIregardingdamsafetyfordetentionBMPs..Themostcommonstructuralfailureofsedimentationbasinsiscausedbypiping.Pipingreferstotwophenomena:(1)waterseepingthroughfine-grainedsoil,erodingthesoilgrainbygrainandformingpipesortunnels;and,(2)waterunderpressureflowingupwardthroughagranularsoilwithaheadofsufficientmagnitudetocausesoilgrainstolosecontactandcapabilityforsupport.Themostcriticalconstructionsequencestopreventpipingwillbe:1.Tightconnectionsbetweenriserandbarrelandotherpipeconnections.2.Adequateanchoringofriser.3.Propersoilcompactionoftheembankmentandriserfooting.4.Properconstructionofanti-seepdevices.Maintenance•Sedimentshallberemovedfromthepondwhenitreaches1—footinStandardsdepth.•Anydamagetothepondembankmentsorslopesshallberepaired.BMPC250:ConstructionStormwaterChemicalTreatmentPurposeThisBMPapplieswhenusingstormwaterchemicalsinbatchtreatmentorflow-throughtreatment.Turbidityisdifficulttocontroloncefineparticlesaresuspendedinstormwaterrunofffromaconstructionsite.Sedimentationpondsareeffectiveatremovinglargerparticulatematterbygravitysettling,butareineffectiveatremovingsmallerparticulatessuchasclayandfinesilt.TraditionalerosionandsedimentcontrolBMPsmaynotbeadequatetoensurecompliancewiththewaterqualitystandardsforturbidityinreceivingwater.Chemicaltreatmentcanreliablyprovideexceptionalreductionsofturbidityandassociatedpollutants.Chemicaltreatmentmayberequiredtomeetturbiditystormwaterdischargerequirements,especiallywhenconstructionistoproceedthroughthewetseason.ConditionsofUseformalwrittenapprovalfromEcologyisrequiredfortheuseofchemicaltreatmentregardlessofsitesize.TheLocalPermittingAuthoritymayalsoohtmeConstructionStonnwaterPollutionFreentionuust2012110 requirereviewandapproval.Whenapproved.thechemicaltreatmentsystemsmustbeincludedintheConstructionStornvaterPollutionPreventionPlan(SWPPP).Designai;dSeeAppendix11-Bforbackgroundinformationonchemicaltreatment.InstalThtio,iSpecificationsCr1naforCIaTranProdUChemicallytreatedstormwaterdischargedfromconstructionsitesmustbenontoxictoaquaticorganisms.TheChemicalTecimologyAssessmentProtocol(CTAPE)mustbeusedtoevaluatechemicalsproposedforstorrnwatertreatment.OnlychemicalsapprovedbyEcologyundertheCTAPEmaybeusedforstormwatertreatment.Theapprovedchemicals,theirallowableapplicationtechniques(batchtreatmentorflow-throughtreatment),allowableapplicationrates,andconditionsofusecanbefoundattheDepartmentofEcologyEmergingTechnologieswebsite:http://www.ecy.wa.gov/programs/wq/stormwater/newtechltechnologies.html.TranSDInConIdraionThedesignandoperationofachemicaltreatmentsystemshouldtakeintoconsiderationthefactorsthatdetermineoptimum,cost-effectiveperformance.Itisimportanttorecognizethefollowing:.OnlyEcologyapprovedchemicalsmaybeusedandmustfollowapproveddoserate..ThepHofthestormwatermustbeintheproperrangeforthepolymerstobeeffective,whichistypically6.5to8.5.Thecoagulantmustbemixedrapidlyintothewatertoensureproperdispersion..Aflocculationstepisimportanttoincreasetherateofsettling,toproducethelowestturbidity,andtokeepthedosagerateaslowaspossible.IToolittleenergyinputintothewaterduringtheflocculationphaseresultsinfloesthataretoosmalland/orinsufficientlydense.Toomuchenergycanrapidlydestroyfloeasitisformed..Caremustbetakeninthedesignofthewithdrawalsystemtominimizeoutflowvelocitiesandtopreventfloedischarge.Dischargefromabatchtreatmentsystemshouldbedirectedthroughaphysicalfiltersuchasavegetatedswalethatwouldcatchanyunintendedfloedischarge.Currently,flow-throughsystemsalwaysdischargethroughthechemicallyenhancedsandfiltrationsystem..Systemdischargeratesmusttakeintoaccountdownstreamconveyanceintegrity.olumeConstructionStormwaterPollutionFreentionuus!2012111 PorBaTranProDriionAbatchchemicaltreatmentsystemconsistsofthestormwatercollectionsystem(eithertemporarydiversionorthepermanentsitedrainagesystem).astoragepond,pumps,achemicalfeedsystem,treatmentcells,andinterconnectingpiping.Thebatchtreatmentsystemshalluseaminimumoftwolinedtreatmentcellsinadditiontoanuntreatedstormwaterstoragepond.Multipletreatmentcellsallowforclarificationoftreatedwaterwhileothercellsarebeingfilledoremptied.Treatmentcellsmaybepondsortanks.Pondswithconstructedearthenembankrnentsgreaterthansixfeethighorwhichimpoundmorethan10acre-feetrequirespecialengineeringanalyses.TheEcologyDamSafetySectionhasspecificdesigncriteriafordarnsinWashingtonState(seehttp://www.ecy.wa.gov/programs/wr/dams!GuidanceDocs.htrnl).Storrnwateriscollectedatinterceptionpoint(s)onthesiteandisdivertedbygravityorbypumpingtoanuntreatedstormwaterstoragepondorotheruntreatedstorrnwaterholdingarea.Thestorrnwaterisstoreduntiltreatmentoccurs.Itisimportantthattheholdingpondbelargeenoughtoprovideadequatestorage.ThefirststepinthetreatmentsequenceistocheckthepHofthestorrnwaterintheuntreatedstormwaterstoragepond.ThepHisadjustedbytheapplicationofcarbondioxideorabaseuntilthestonnwaterinthestoragepondiswithinthedesiredpHrange,6.5to2.5.Whenused,carbondioxideisaddedimmediatelydownstreamofthetransferpump.Typicallysodiumbicarbonate(bakingsoda)isusedasabase,althoughotherbasesmaybeused.Whenneeded,baseisaddeddirectlytotheuntreatedstormwaterstoragepond.Thestormwaterisrecirculatedwiththetreatmentpumptoprovidemixinginthestoragepond.InitialpHadjustmentsshouldbebasedondailybenchtests.FurtherpHadjustmentscanbemadeatanypointintheprocess.OncethestormwateriswithinthedesiredpHrange(dependantonpolymerbeingused),thestormwaterispumpedfromtheuntreatedstormwaterstoragepondtoatreatmentcellaspolymerisadded.Thepolymerisaddedupstreamofthepumptofacilitaterapidmixing.Afterpolymeraddition,thewateriskeptinalinedtreatmentcellforclarificationofthesediment-floe.Inabatchmodeprocess,clarificationtypicallytakesfrom30minutestoseveralhours.PriortodischargesamplesarewithdrawnforanalysisofpH,flocculentchemicalconcentration,andturbidity.Ifbothareacceptable,thetreatedwaterisdischarged.Severalconfigurationshavebeendevelopedtowithdrawtreatedwaterfromthetreatmentcell.TheoriginalconfigurationisadevicethatwithdrawsthetreatedwaterfromjustbeneaththewatersurfaceusingaolumeConstructionStoriln%’aterPollutionPreentionuust2012112 floatwithadjustablestrutsthatpreventthefloatfromsettlingonthecellbottom.ThisreducesthepossibilityofpickingUI)sediment-floefromthebottomofthepond.Thestrutsareusuallysetataminimumclearanceofabout12inches;thatis.thefloatwillcomewithin12inchesofthebottomofthecell.Othersystemshaveusedverticalguidesorcableswhichconstrainthefloat,allowingittodriftupanddownwiththewaterlevel.MorerecentdesignshaveanH-shapedarrayofpipes,setonthehorizontal.Thisschemeprovidesforwithdrawalfi’omfourpointsratherthanone.Thisconfigurationreducesthelikelihoodofsuckingsettledsolidsfromthebottom.Italsoreducesthetendencyforavortextoform.Inletdiffusers,alongfloatingorfixedpipewithmanysmallholesinit,arealsoanoption.Safetyisaprimaryconcern.Designshouldconsiderthehazardsassociatedwithoperations,suchassampling.Facilitiesshouldbedesignedtoreducesliphazardsanddrowning.Tanksandpondsshouldhaveliferings,ladders,orstepsextendingfromthebottomtothetop.PorBaTranProPriionAtaminimum,aflow-throughchemicaltreatmentsystemconsistsofthestormwatercollectionsystem(eithertemporarydiversionorthepermanentsitedrainagesystem),anuntreatedstorrnwaterstoragepond,andthechemicallyenhancedsandfiltrationsystem.Stormwateriscollectedatinterceptionpoint(s)onthesiteandisdivertedbygravityorbypumpingtoanuntreatedstorrnwaterstoragepondorotheruntreatedstormwaterholdingarea.Thestormwaterisstoreduntiltreatmentoccurs.Itisimportantthattheholdingpondbelargeenoughtoprovideadequatestorage.Stormwateristhenpumpedfromtheuntreatedstonnwaterstoragepondtothechemicallyenhancedsandfiltrationsystemwherepolymerisadded.AdjustmentstopHmaybenecessarybeforechemicaladdition.ThesandfiltrationsystemcontinuallymonitorsthestormwaterforturbidityandpH.IfthedischargewateriseveroutofanacceptablerangeforturbidityorpH,thewaterisrecycledtotheuntreatedstormwaterpondwhereitcanberetreated.forbatchtreatmentaitdflow-throug!itreatmeiit,thefollowingequipmentshouldbelocatedinalockableshed:.Thechemicalinjector..Secondarycontainmentforacid,caustic,bufferingcompound,andtreatmentchemical.IEmergencyshowerandeyewash..MonitoringequipmentwhichconsistsofapHmeterandaturbidimeter.olumeConstructionStormwaterPollutionPreentionuust20121] SSun:Certainsitesarerequiredtoimplementflowcontrolforthedevelopedsites.Thesesitesmustalsocontrolstormwatcrreleaseratesduringconstruction.Generally,thesearesitesthatdischargestormwaterdirectly.orindirectly,throughaconveyancesystem,intoafreshwater.Systemsizingisdependentonflowcontrolrequirements.SiinCririaforBaTranSforFoConroEWarBodiThetotalvolumeoftheuntreatedstormwaterstoragepondandtreatmentpondsortanksmustbelargeenoughtotreatstormwaterthatisproducedduringmultipledaystormevents.Itisrecommendedthatataminimumtheuntreatedstoirriwaterstoragepondbesizedtohold1.5timestherunoffvolumeofthe10-year,24-hourstormevent.Bypassshouldbeprovidedaroundthechemicaltreatmentsystemtoaccommodateextremestormevents.RunoffvolurneshallbecalculatedusingthemethodspresentedinVolume3,Chapter2.Worst-caselandcoverconditions(i.e.,producingthemostrunoff)shouldbeusedforanalyses(inmostcases,thiswouldbethelandcoverconditionsjustpriortofinallandscaping).Primarysettlingshouldbeencouragedintheuntreatedstormwaterstoragepond.Aforebaywithaccessformaintenancemaybebeneficial.Therearetwoopposingconsiderationsinsizingthetreatmentcells.Alargercellisabletotreatalargervolumeofwatereachtimeabatchisprocessed.However,thelargerthecellthelongerthetimerequiredtoemptythecell.Alargercellmayalsobelesseffectiveatflocculationandthereforerequirealongersettlingtime.Thesimplestapproachtosizingthetreatmentcellistomultiplytheallowabledischargeflowratetimesthedesireddrawdowntime.A4-hourdrawdowntimeallowsonebatchpercellper8-hourworkperiod,given1hourofflocculationfollowedbytwohoursofsettling.IfthedischargeisdirectlytoaflowcontrolexemptreceivingwaterlistedinAppendixI-EofVolumeIortoaninfiltrationsystem,thereisnodischargeflowlimit.Pondssizedforflowcontrolwaterbodiesmustataminimummeetthesizingcriteriaforflowcontrolexemptwaters.SiinCririaforFo-TroTranSforFoConroEWarBodiWhensizingstoragepondsortanksforflow-throughsystemsforflowcontrolexemptwaterbodies,thetreatmentsystemcapacityshouldbeafactor.Theuntreatedstormwaterstoragepondortankshouldbesizedtohold1.5timestherunoffvolumeofthe10-year,24-hourstormeventminusthetreatmentsystemflowrateforan8-hourperiod.Forachitosanenhancedsandfiltrationsystem,thetreatmentsystemflowrateshouldbesizedusingahydraulicloadingratebetween6-8gpmlft2.OtherhydraulicolumeConstructionStornnraterPollutionPreentionuust201211 loadingratesmaybemoreappropriateforothersystems.Bypassshouldbeprovidedaroundthechemicaltreatmentsystemtoaccommodateextremestorms.RunoffvolurneshallbecalculatedusingthemethodspresentedinVolume3,Chapter2.Worst-caselandcoverconditions(i.e.,producingthemostrunoff)shouldbeusedforanalyses(inmostcases,thiswouldbethelandcoverconditionsjustpriortofinallandscaping).SiinCr1riaforFoConroWarBodiSitesthatmustimplementflowcontrolforthedevelopedsiteconditionmustalsocontrolstormwaterreleaseratesduringconstruction.Constructidnsitestormwaterdischargesshallnotexceedthedischargedurationsofthepre-developedconditionfortherangeofpre-developeddischargeratesfromofthe2-yearflowthroughthe10-yearflowaspredictedbyanapprovedcontinuousrunoffmodel.Thepre-developedconditiontobematchedshallbethelandcoverconditionimmediatelypriortothedevelopmentproject.Thisrestrictiononreleaseratescanaffectthesizeofthestoragepondandtreatmentcells.ThefollowingishowWWHMcanbeusedtodeterminethereleaseratesfromthechemicaltreatmentsystems:1.Determinethepre-developedflowdurationstobematchedbyenteringtheexistinglanduseareaunderthe“Pre-developed”scenarioinWWHM.Thedefaultflowrangeisfrom½ofthe2-yearflowthroughthe10-yearflow.2.Enterthepostdevelopedlanduseareainthe“DevelopedUnmitigated”scenarioinWWHM.3.Copythelanduseinformationfromthe“DevelopedUnmitigated”to“DevelopedMitigated”scenario.4.Whileinthe“DevelopedMitigated”scenario,addapondelementunderthebasinelementcontainingthepost-developedlanduseareas.Thispondelementrepresentsinformationontheavailableuntreatedstormwaterstorageanddischargefromthechemicaltreatmentsystem.Incaseswherethedischargefromthechemicaltreatmentsystemiscontrolledbyapump,astage/storage/discharge(SSD)tablerepresentingthepondmustbegeneratedoutsideWWHMandimportedintoWWHM.WWHMcanroutetherunofffromthepost-developedconditionthroughthisSSDtable(thepond)anddeterminecompliancewiththeflowdurationstandard.ThiswouldbeaniterativedesignprocedurewhereiftheinitialSSDtableprovedtobeinadequate,thedesignerwouldhavetomodifytheSSDtableoutsideWWHMandre-importinWWHMandroutetherunoffthroughitagain.Theiterationwillcontinueuntilapondthatcomplieswiththeflowdurationstandardiscorrectlysized.NotesonSSDtablecharacteristics:olumeConstructionStomiwaterPollutionPreentionuust201211 .Thepumpdischargeratewouldlikelybeinitiallysetatjustbelow‘/2ofthe2-yearflowfromthepre-developedcondition.Asrunoffcomingintotheuntreatedstormwaterstoragepondincreasesandtheavailableuntreatedstoririwaterstoragevolumegetsusedup,itwouldbenecessarytoincreasethepumpdischargerateabove‘Aofthe2-year.Theincrease(s)above1/2ofthe2-yearmustbesuchthattheyprovidesomerelieftotheuntreatedstorrnwaterstorageneedsbutatthesametimewillnotcauseviolationsoftheflowdurationstandardatthehigherflows.ThefinaldesignSSDtablewillidentifytheappropriatepumpingratesandthecorrespondingstageandstorages..Whenbuildingsuchaflowcontrolsystem,thedesignmustensurethatanyautomaticadjustmentstothepumpingrateswillbeasaresultofchangestotheavailablestorageinaccordancewiththefinaldesignSSDtable.5.Itshouldbenotedthattheaboveprocedureswouldbeusedtomeettheflowcontrolrequirements.Thechemicaltreatmentsystemmustbeabletomeettherunofftreatmentrequirements.Itislikelythatthedischargeflowrateof%ofthe2-yearormoremayexceedthetreatmentcapacityofthesystem.Ifthatisthecase,theuntreatedstormwaterdischargerate(s)(i.e.,influenttothetreatmentsystem)mustbereducedtoallowpropertreatment.Anyreductionintheflowswouldlikelyresultintheneedforalargeruntreatedstormwaterstoragevolume.Ifthedischargeistoamunicipalstormdrainagesystem,theallowabledischargeratemaybelimitedbythecapacityofthepublicsystem.Itmaybenecessarytocleanthemunicipalstormdrainagesystempriortothestartofthedischargetopreventscouringsolidsfromthedrainagesystem.Ifthemunicipalstormdrainagesystemdischargestoawaterbodynotontheflowcontrolexemptlist,theprojectsiteissubjecttoflowcontrolrequirements.Obtainpermissionfromtheownerofthecollectionsystembeforedischargingtoit.Ifsystemdesigndoesnotallowyoutodischargeattheslowerratesasdescribedaboveandifthesitehasaretentionordetentionpondthatwillservetheplanneddevelopment,thedischargefromthetreatmentsystemmaybedirectedtothepermanentretention/detentionpondtocomplywiththeflowcontrolrequirement.Inthiscase,theuntreatedstorrnwaterstoragepondandtreatmentsystemwillbesizedaccordingtothesizingcriteriaforflow-throughtreatmentsystemsforflowcontrolexemptwaterbodiesdescribedearlierexceptalldischarge(waterpassingthroughthetreatmentsystemandstorrnwaterbypassingthetreatmentsystem)willbedirectedintothepermanentretention/detentionpond.Ifsiteconstraintsmakelocatingtheuntreatedstormwaterstorageponddifficult,thepermanentretention/detentionpondmaybedividedtoserveastheuntreatedstormwaterstoragepondandthepost-treatmentflowcontrolpond.AbermorbarriermustbeusedinthiscasesotheuntreatedwaterdoesnotmixwiththetreatedolumeConstructionStorrnwaterPollutionPreentionitust201211 water.Bothuntreatedstormwaterstoragerequirements,andadequatepost-treatmentflowcontrolmustbeachieved.Thepost-treatmentflowcontrolpond’sreviseddimensionsmustbeenteredintotheWWHMandtheWWHMmustberuntoconfirmcompliancewiththeflowcontrolrequirement.AIaii;te,ianceMoniorinAtaminimum,thefollowingmonitoringshallbeStandardsconducted.Testresultsshallberecordedonadailylogkeptonsite.AdditionaltestingmayberequiredbytheNPDESpermitbasedonsiteconditions.OperationalMonitoring:.Totalvolumetreatedanddischarged..Flowmustbecontinuouslymonitoredandrecordedatnotgreaterthan15-minuteintervals..TypeandamountofchemicalusedforpHadjustment..Amountofpolyrnerusedfortreatment.ISettlingtime.ComplianceMonitoring:.InfluentandeffluentpH,flocculentchemicalconcentration,andturbiditymustbecontinuouslymonitoredandrecordedatnotgreaterthan15-minuteintervals.pHandturbidityofthereceivingwater.Biomonitoring:Treatedstormwatermustbenon-toxictoaquaticorganisms.Treatedstormwatermustbetestedforaquatictoxicityorresidualchemicals.FrequencyofbiomonitoringwillbedeterminedbyEcology.ResidualchemicaltestsmustbeapprovedbyEcologypriortotheiruse.Iftestingtreatedstormwaterforaquatictoxicity,youmusttestforacute(lethal)toxicity.BioassaysshallbeconductedbyalaboratoryaccreditedbyEcology,unlessotherwiseapprovedbyEcology.AcutetoxicitytestsshallbeconductedpertheCTAPEprotocol.DiarCoIanPriorodiar,radoraradanddforoIanIH,foiiíaonnraion,andrMiIi.TheselimitsmaybeestablishedbytheConstructionStormwaterGeneralPermitorasite-specificdischargepermit.Samplingandtestingforotherpollutantsmayalsobenecessaryatsomesites.pHmustbewithintherangeof6.5to8.5standardunitsandnotcauseachangeinthepHofthereceivingwaterofmorethan0.2standardunits.Treatedstormwatersamplesandmeasurementsshallbetakenfromthedischargepipeoranotherlocationrepresentativeofthenatureofthetreatedstormwaterdischarge.Samplesusedfordeterminingcompliancewiththewaterqualitystandardsinthereceivingwatershallnotbetakenfromthetreatmentpondpriortodecanting.Compliancewiththewaterqualitystandardsisdeterminedinthereceivingwater.olumeConstructionStormwaterPollutionPreentionuust201211 0raorTraininEachcontractorwhointendstousechemicaltreatmentshallbetrainedbyanexperiencedcontractor.EachsiteusingchemicaltreatmentmusthaveanoperatortrainedandcertifiedbyanorganizationapprovedbyEcology.SandardBl1PSurfacestabilizationBMPsshouldbeimplementedonsitetopreventsignificanterosion.Allsitesshalluseatruckwheelwashtopreventtrackingofsedimentoffsite.SdfnRoaandDioa.Sedimentshallberemovedfromthestorageortreatmentcellsasnecessary.Typically,sedimentremovalisrequiredatleastonceduringawetseasonandatthedecommissioningofthecells.Sedimentremaininginthecellsbetweenbatchesmayenhancethesettlingprocessandreducetherequiredchemicaldosage..Sedimentthatisknowntobenon-toxicmaybeincorporatedintothesiteawayfromdrainages.BMPC251:ConstructionStormwaterFiltrationPuiposefiltrationremovessedimentfromrunofforiginatingfromdisturbedareasofthesite.BackgroundInformation:filtrationwithsandmediahasbeenusedforoveracenturytotreatwaterandwastewater.Theuseofsandfiltrationfortreatmentofstormwaterhasdevelopedrecently,generallytotreatrunofffromstreets,parkinglots,andresidentialareas.Theapplicationoffiltrationtoconstructionstorrnwatertreatmentiscurrentlyunderdevelopment.ConditionsofUseTraditionalBMPsusedtocontrolsoilerosionandsedimentlossfromsitesunderdevelopmentmaynotbeadequatetoensurecompliancewiththewaterqualitystandardforturbidityinthereceivingwater.Filtrationmaybeusedinconjunctionwithgravitysettlingtoremovesedimentassmallasfinesilt(0.5jim).Thereductioninturbiditywillbedependentontheparticlesizedistributionofthesedimentinthestorrnwater.Insomecircumstances,sedimentationandfiltrationmayachievecompliancewiththewaterqualitystandardforturbidity.TheuseofconstructionstorrnwaterfiltrationdoesnotrequireapprovalfromEcologyaslongastreatmentchemicalsarenotused.FiltrationinconjunctionwithpolymertreatmentrequirestestingundertheChemicalTechnologyAssessmentProtocol—Ecology(CTAPE)beforeitcanbeinitiated.ApprovalfromtheappropriateregionalEcologyofficemustbeobtainedateachsitewherepolymersuseisproposedpriortouse.FormoreguidanceonstormwaterchemicaltreatmentseeBMPC250.olumeConstnictionStormwaterPollutionPreentionuus!201211 Desigi;andTwotypesoffiltrationsystemsmaybeappliedtoconstructionstormwaterInstctllatioi,treatment:rapidandslow.RapidsandfiltersarethetypicalsystemusedSpecificcztionsforwaterandwastewatertreatment.Theycanachieverelativelyhighhydraulicflowrates,ontheorderof2to20gpm/sf.becausetheyhaveautomaticbackwashsystemstoremoveaccumulatedsolids.Incontrast.slowsandfiltershaveverylowhydraulicrates,ontheorderof0.02grn!sf,becausetheydonothavebackwashsystems.Slowsandfiltrationhasgenerallybeenusedtotreatstorrnwater.Slowsandfiltrationismechanicallysimpleincomparisontorapidsandfiltrationbutrequiresamuchlargerfilterarea.FlraionEIii.Sandmediafiltersareavailablewithautomaticbackwashingfeaturesthatcanfilterto50jimparticlesize.Screenorbagfilterscanfilterdownto5tm.Fiberwoundfilterscanremoveparticlesdownto0.5irn.Filtersshouldbesequencedfromthelargesttothesmallestporeopening.Sedimentremovalefficiencywillberelatedtoparticlesizedistributioninthestormwater.TranProDriion.Stonnwateriscollectedatinterceptionpoint(s)onthesiteandisdivertedtoanuntreatedstorrnwatersedimentpondortankforremovaloflargesedimentandstorageofthestormwaterbeforeitistreatedbythefiltrationsystem.Theuntreatedstormwaterispumpedfromthetrap,pond,ortankthroughthefiltrationsysteminarapidsandfiltrationsystem.Slowsandfiltrationsystemsaredesignedasflowthroughsystemsusinggravity.Maintena,;ceRapidsandfilterstypicallyhaveautomaticbackwashsystemsthatareStandardstriggeredbyapre-setpressuredropacrossthefilter.Ifthebackwashwatervolumeisnotlargeorsubstantiallymoreturbidthantheuntreatedstormwaterstoredintheholdingpondortank,backwashreturntotheuntreatedstormwaterpondortankmaybeappropriate.However,othermeansoftreatmentanddisposalmaybenecessary..Screen,bag,andfiberfiltersmustbecleanedand/orreplacedwhentheybecomeclogged..Sedimentshallberemovedfromthestorageand/ortreatmentpondsasnecessary.Typically,sedimentremovalisrequiredonceortwiceduringawetseasonandatthedecommissioningoftheponds.SiinCr1riaforFo-TroTranSforFoConroEWarBodiWhensizingstoragepondsortanksforflow-throughsystemsforflowcontrolexemptwaterbodiesthetreatmentsystemcapacityshouldbeafactor.Theuntreatedstormwaterstoragepondortankshouldbesizedtohold1.5timestherunoffvolumeofthe10-year,24-hourstormeventminusthetreatmentsystemflowrateforan8-hourperiod.Forachitosanenhancedsandfiltrationsystem,thetreatmentsystemflowrateshouldbesizedusingahydraulicloadingratebetween6-8gpm/ft2.OtherhydraulicolumeConstructionStorrn%’aterPollutionPreentionuust201211 loadingratesmaybemoreappropriateforothersystems.Bypassshouldbeprovidedaroundthechemicaltreatmentsystemtoaccommodateextremestorms.RunoffvolumeshallbecalculatedusingthemethodspresentedinVolume3,Chapter2.Worst-caseconditions(i.e..producingthemostrunoff)shouldbeusedforanalyses(mostlikelyconditionspresentpriortofinallandscaping).SiinCr1naforF0ConroWarBodiSitesthatmustimplementflowcontrolforthedevelopedsiteconditionmustalsocontrolstonriwaterreleaseratesduringconstruction.Constructionsitestormwaterdischargesshallnotexceedthedischargedurationsofthepre-developedconditionfortherangeofpre-developeddischargeratesfrom1/2ofthe2-yearflowthroughthe10-yearflowaspredictedbyanapprovedcontinuousrunoffmodel.Thepre-developedconditiontobematchedshallbethelandcoverconditionimmediatelypriortothedevelopmentproject.Thisrestrictiononreleaseratescanaffectthesizeofthestoragepond,thefiltrationsystem,andtheflowratethroughthefiltersystem.ThefollowingishowWWHMcanbeusedtodeterminethereleaseratesfromthefiltrationsystems:1.Determinethepre-developedflowdurationstobematchedbyenteringthelanduseareaunderthe“Pre-developed”scenarioinWWHM.Thedefaultflowrangeisfrom,4ofthe2-yearflowthroughthe10-yearflow.2.Enterthepostdevelopedlanduseareainthe“DevelopedUnmitigated”scenarioinWWHM.3.Copythelanduseinformationfromthe“DevelopedUnmitigated”to“DevelopedMitigated”scenario.4.Therearetwopossiblewaystomodelstorrnwaterfiltrationsystems:a.Thestormwaterfiltrationsystemusesanuntreatedstormwaterstoragepond/tankandthedischargefromthispond/tankispumpedtooneormorefilters.In-linefiltrationchemicalswouldbeaddedtotheflowrightafterthepond/tankandbeforethefilter(s).Becausethedischargeispumped,WWHMcan’tgenerateastage/storage/discharge(SSD)tableforthissystem.ThissystemismodeledthesamewayasdescribedinBMPC250andisasfollows:Whileinthe“DevelopedMitigated”scenario,addapondelementunderthebasinelementcontainingthepost-developedlanduseareas.Thispondelementrepresentsinformationontheavailableuntreatedstorrnwaterstorageanddischargefromthefiltrationsystem.Incaseswherethedischargefromthefiltrationsystemiscontrolledbyapump,astage/storage/discharge(S$D)tablerepresentingthepondmustbegeneratedoutsideWWHMandohiineConstructionStorrnwaterPollutionFreentionuust2012120 importedintoWWHM.WWHMcanroutetherunofffromthepost-developedconditionthroughthisSSDtable(thepond)anddeterminecompliancewiththeflowdtirationstandard.ThiswouldbeaniterativedesignprocedurewhereiftheinitialSSDtableprovedtobeoutofcornpliance.thedesignerwouldhavetomodifytheSSDtableoutsideWWHMandre-importinWWHMandroutetherunoffthroughitagain.Theiterationwillcontinueuntilapondthatenablescompliancewiththeflowdurationstandardisdesigned.NotesonSSDtablecharacteristics:IThepumpdischargeratewouldlikelybeinitiallysetatjustbelow‘/2ifthe2-yearflowfromthepre-developedcondition.Asrunoffcomingintotheuntreatedstormwaterstoragepondincreasesandtheavailableuntreatedstorrnwaterstoragevolumegetsusedup,itwouldbenecessarytoincreasethepumpdischargerateabove/2ofthe2-year.Theincrease(s)above4ofthe2-yearmustbesuchthattheyprovidesomerelieftotheuntreatedstormwaterstorageneedsbutatthesametimetheywillnotcauseviolationsoftheflowdurationstandardatthehigherflows.ThefinaldesignSSDtablewillidentifytheappropriatepumpingratesandthecorrespondingstageandstorages..Whenbuildingsuchaflowcontrolsystem,thedesignmustensurethatanyautomaticadjustmentstothepumpingrateswillbeasaresultofchangestotheavailablestorageinaccordancewiththefinaldesignSSDtable.b.Thestormwaterfiltrationsystemusesastoragepond/tankandthedischargefromthispond/tankgravityflowstothefilter.ThisisusuallyaslowsandfiltersystemanditispossibletomodelitinWWHMasaFilterelementorasacombinationofPondandfilterelementplacedinseries.Thestage/storage/dischargetable(s)maythenbegeneratedwithinWWHMasfollows:(i)Whileinthe“DevelopedMitigated”scenario,addaFilterelementunderthebasinelementcontainingthepost-developedlanduseareas.Thelengthandwidthofthisfilterelementwouldhavetobethesameasthebottomlengthandwidthoftheupstreamuntreatedstormwaterstoragepond/tank.(ii)Incaseswherethelengthandwidthofthefilterisnotthesameasthoseforthebottomoftheupstreamuntreatedstorrnwaterstoragetank/pond,thetreatmentsystemmaybemodeledasaPondelementfollowedbyaFilterelement.Byhavingthesetwoelements,WWHMwouldthengeneratea$$DtableforthestoragepondwhichthengravityflowstotheFilterelement.ThefilterelementdownstreamoftheuntreatedstormwaterolumeConstructionStormwaterPollutionFreentionitust2012121 storagepondwouldhaveastoragecomponentthroughthemedia,andanoverflowcomponentforwhenthefiltrationcapacityisexceeded.WWHMcanroutetherunofffromthepost-developedconditionthroughthetreatmentsystemsin4banddeterrriinecompliancewiththeflowdurationstandard.Thiswouldbeaniterativedesignprocedurewhereiftheinitialsizingestimatesforthetreatmentsystemprovedtobeinadequate,thedesignerwouldhavetomodifythesystemandroutetherunoffthroughitagain.Theiterationwouldcontinueuntilcompliancewiththeflowdurationstandardisachieved.5.Itshouldbenotedthattheaboveprocedureswouldbeusedtomeettheflowcontrolrequirements.Thefiltrationsystemmustbeabletomeetthemnofftreatrnentrequirements.Itislikelythatthedischargeflowrateof4ofthe2-yearormoremayexceedthetreatmentcapacityofthesystem.Ifthatisthecase,theuntreatedstormwaterdischargerate(s)(i.e.,mfluenttothetreatmentsystem)mustbereducedtoallowpropertreatment.Anyreductionintheflowswouldlikelyresultintheneedforalargeruntreatedstorrnwaterstoragevolume.Ifsystemdesigndoesnotallowyoutodischargeattheslowerratesasdescribedaboveandifthesitehasaretentionordetentionpondthatwillservetheplanneddevelopment,thedischargefromthetreatmentsystemmaybedirectedtothepermanentretention/detentionpondtocomplywiththeflowcontrolrequirements.Inthiscase,theuntreatedstormwaterstoragepondandtreatmentsystemwillbesizedaccordingtothesizingcriteriaforflow-throughtreatmentsystemsforflowcontrolexemptwaterbodiesdescribedearlierexceptalldischarges(waterpassingthroughthetreatmentsystemandstormwaterbypassingthetreatmentsystem)willbedirectedintothepermanentretentionldetentionpond.Ifsiteconstraintsmakelocatingtheuntreatedstorrnwaterstorageponddifficult,thepermanentretention/detentionpondmaybedividedtoserveastheuntreatedstormwaterdischargepondandthepost-treatmentflowcontrolpond.Abermorbarriermustbeusedinthiscasesotheuntreatedwaterdoesnotmixwiththetreatedwater.Bothuntreatedstormwaterstoragerequirements,andadequatepost-treatmentflowcontrolmustbeachieved.Thepost-treatmentflowcontrolpond’sreviseddimensionsmustbeenteredintotheWWHMandtheWWHMmustberuntoconfirmcompliancewiththeflowcontrolrequirement.olunieConstiuctionStol7nwaterPollutionPreentionuust2012122 BMPC252:HighpHNeutralizationUsingCO2PiuposeWhenpHlevelsinstormwaterriseabove8.5itisnecessarytolowerthepHlevelstotheacceptablerangeof6.5to8.5.thisprocessiscalledpHneutralization.iHneutralizationinvolvestheuseofsolidorcompressedcarbondioxidegasinwaterrequiringneutralization.NeutralizedstormwateririaybedischargedtosurfacewatersundertheGeneralConstructionNPDESpermit.Neutralizedprocesswatersuchasconcretetruckwash-out,hydrodemolition,orsaw-cuttingslurrymustbemanagedtopreventdischargetosurfacewaters.Anystormwatercontaminatedduringconcreteworkisconsideredprocesswastewaterandmustnotbedischargedtosurfacewaters.RaonforHNraiaionApHlevelrangeof6.5to8.5istypicalformostnaturalwatercourses,andthisneutralpHisrequiredforthesurvivalofaquaticorganisms.ShouldthepHriseordropoutofthisrange,fishandotheraquaticorganismsmaybecomestressedandmaydie.CalciumhardnesscancontributetohighpHvaluesandcausetoxicitythatisassociatedwithhighpHconditions.Ahighlevelofcalciumhardnessinwatersofthestateisnotallowed.ThewaterqualitystandardforpHinWashingtonStateisintherangeof6.5to8.5.GroundwaterstandardforcalciumandotherdissolvedsolidsinWashingtonStateislessthan500mg/i.ConditionsofUseCaofHiHHighpHatconstructionsitesismostcomiiaonlycausedbythecontactofstormwaterwithpouredorrecycledconcrete,cement,mortars,andotherPortlandcementorlimecontainingconstructionmaterials.(SeeBMPCi51:ConcreteHandlingformoreinformationonconcretehandlingprocedures).Theprincipalcausticagentincementiscalciumhydroxide(freelime).AdanaofCO2$arin.RapidlyneutralizeshighpHwater..Costeffectiveandsafertohandlethaiiacidcompounds..CO2isself-buffering.ItisdifficulttooverdoseandcreateharmfullylowpHlevels..Materialisreadilyavailable.ohimeConstructionStornnvaterPollutionPreentionuust201212 TClaProWhencarbondioxide(C02)isaddedtowater(H20),carbonicacid(H2C03)isformedwhichcanfurtherdissociateintoaproton(H±)andabicarbonateanion(HCO3)asshownbelow:C02+H20<-*H2C03-*H++HC03ThefreeprotonisaweakacidthatcanlowerthepH.Watertemperaturehasaneffectonthereactionaswell.Thecolderthewatertemperatureistheslowerthereactionoccursandthewarmerthewatertemperatureisthequickerthereactionoccurs.MostconstructionapplicationsinWashingtonStatehavewatertemperaturesinthe50°forhigherrangesothereactionisalmostsimultaneous.DesignandTraiiProI,;stallation.••HighpHwatermaybetreatedusingcontinuoustreatment,continuousSpecifications.•dischargesystems.ThesemanufacturedsystemscontinuouslyrnomtorinfluentandeffluentpHtoensurethatpHvaluesarewithinanacceptablerangebeforebeingdischarged.AllsystemsmusthavefailsafeautomaticshutoffswitchesintheeventthatpHisnotwithintheacceptabledischargerange.Onlytrainedoperatorsmayoperatemanufacturedsystems.Systemmanufacturersoftenprovidetrainedoperatorsortrainingontheirdevices.Thefollowingproceduremaybeusedwhennotusingacontinuousdischargesystem:1.Priortotreatment,theappropriatejurisdictionshouldbenotifiedinaccordancewiththeregulationssetbythejurisdiction.2.EveryeffortshouldbemadetoisolatethepotentialhighpHwaterinordertotreatitseparatelyfromotherstormwateron-site.3.Watershouldbestoredinanacceptablestoragefacility,detentionpond,orcontainmentcellpriortotreatment.4.Transferwatertobetreatedtothetreatmentstructure.Ensurethattreatmentstructuresizeissufficienttoholdtheamountofwaterthatistobetreated.Donotfilltankcompletely,allowatleast2feetoffreeboard.5.TheoperatorsamplesthewaterforpHandnotestheclarityofthewater.Asaruleofthumb,lessC02isnecessaryforclearerwater.Thisinformationshouldberecorded.6.InthepHadjustmentstructure,addC02untilthepHfallsintherangeof6.9-7.1.RememberthatpHwaterqualitystandardsapplysoadjustingpHtowithin0.2pHunitsofreceivingwater(backgroundpH)isrecommended.ItisunlikelythatpHcanbeadjustedtowithin0.2pHunitsusingdryice.CompressedcarbondioxidegasshouldbeintroducedtothewaterusingacarbondioxidediffuserlocatednearolumeConstructio,iStormwaterPollutionPreentioizuust201212 thebottomofthetank,thisvi11allowcarbondioxidetobubbleupthroughthewateranddiffusemoreevenly.7.SlowlydischargethewatermakingsurewaterdoesnotgetstilTedupintheprocess.Releaseabout80%ofthewaterfromthestructureleavinganysludgebehind.8.Dischargetreatedwaterthroughapondordrainagesystem.9.Excesssludgeneedstobedisposedofproperlyasconcretewaste.IfseveralbatchesofwaterareundergoingpHtreatment,sludgecanbeleftintreatmentstructureforthenextbatchtreatment.Disposeofsludgewhenitfills50%oftankvolume.Sitesthatmustimplementflowcontrolforthedevelopedsitemustalsocontrolstormwaterreleaseratesduringconstruction.Alltreatedstormwatermustgothroughaflowcontrolfacilitybeforebeingreleasedtosurfacewaterswhichrequireflowcontrol.MaintenanceSafandManaHandinStandards...AllequipmentshouldbehandledinaccordancewithOSHArulesandregulations..Followmanufacturerguidelinesformaterialshandling.0raorRordEachoperatorshouldprovide:.Adiagramofthemonitoringandtreatmentequipment..Adescriptionofthepumpingratesandcapacitythetreatmentequipmentiscapableoftreating.Eachoperatorshouldkeepawrittenrecordofthefollowing:IClientnameandphonenumber..Dateoftreatment..Weatherconditions..Projectnameandlocation..Volumeofwatertreated..pHofuntreatedwater..AmountofCO2neededtoadjustwatertoapHrangeof6.9-7.1..pHoftreatedwater..Dischargepointlocationanddescription.Acopyofthisrecordshouldbegiventotheclient/contractorwhoshouldretaintherecordforthreeyears.olumeConstructionStorrnwaterPollutionPreentionuust201212 BMPC253:pHControlforHighpHWaterPitiposeWhenpHlevelsinstormwaterriseabove8.5itisnecessarytolowerthepHlevelstotheacceptablerangeof6.5to8.5,thisprocessiscalledpHneutralization.StormwaterwithpHlevelsexceedingwaterqualitystandardsmaybetreatedbyinfiltration,dispersioninvegetationorcompost,pumpingtoasanitarysewer,disposalatapermittedconcretebatchplantwithpHneutralizationcapabilities.orcarbondioxidesparging.BMPC252givesguidelinesforcarbondioxidesparging.RaonforHNralalonApHlevelrangeof6.5to8.5istypicalformostnaturalwatercourses,andthispHrangeisrequiredforthesurvivalofaquaticorganisms.ShouldthepHriseordropoutofthisrange,fishandotheraquaticorganismsmaybecomestressedandmaydie.Co,tditionsofUseCaofHiHHighpHlevelsatconstructionsitesaremostcommonlycausedbythecontactofstormwaterwithpouredorrecycledconcrete,cement,mortars,andotherPortlandcementorlimecontainingconstructionmaterials.(SeeBMPC151:ConcreteHandlingformoreinformationonconcretehandlingprocedures).Theprincipalcausticagentincementiscalciumhydroxide(freelime).DesignandDioaModInstallationInfiraionSpecifications.Infiltrationisonlyallowedifsoiltypeallowsallwatertoinfiltrate(nosurfacerunoff)withoutcausingorcontributingtoaviolationofsurfaceorgroundwaterqualitystandards..InfiltrationtechniquesshouldbeconsistentwithVolumeV,Chapter7DinonUseBMPT5.30FullDispersionSanianSnfloa.Localsewerauthorityapprovalisrequiredpriortodisposalviathesanitarysewer.ConnBaPanDioa.OnlypermittedfacilitiesmayaccepthighpHwater..facilityshouldbecontactedbeforetreatmenttoensuretheycanacceptthehighpHwater.SonanDianAnypHtreatmentoptionsthatgeneratetreatedwaterthatmustbedischargedoffsitearesubjecttoflowcontrolrequirements.SitesthatmustimplementflowcontrolforthedevelopedsitemustalsocontrololumeConstructionStormwaterPollutionFreentionuust201212 stormwaterreleaseratesduringconstruction.Alltreatedstormwatermustgothroughaflowcontrolfacilitybeforebeingreleasedtosurfacewaterswhichrequireflowcontrol.ohtmeConstructionStorinwaterPollutionFreentionuust201212 AppendixCCorrespondenceConstructionstormwaterisnotanticipatedtoleavethesiteatanytimeduringconstruction.Ifstormwateristobedischarged,atanypointduringconstruction,aNPDESpermitshallbeappliedforimmediately.DR.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageC-I AppendixDSiteInspectionFormTheresultsofeachinspectionshallbesummarizedinaninspectionreportorchecklistthatisenteredintoorattachedtothesitelogbook.Itissuggestedthattheinspectionreportorchecklistbeincludedinthisappendixtokeepmonitoringandinspectioninformationinonedocument,butthisisoptional.However,itismandatorythatthisSWPPPandthesiteinspectionformsbekeptonsiteatalltimesduringconstruction,andthatinspectionsbeperformedanddocumentedasoutlinedbelow.Ataminimum,eachinspectionreportorchecklistshallinclude:Inspectiondate/timesWeatherinformation:generalconditionsduringinspection,approximateamountofprecipitationsincethelastinspection,andapproximateamountofprecipitationwithinthelast24hours.AsummaryorlistofallBMPsthathavebeenimplemented,includingobservationsofallerosion/sedimentcontrolstructuresorpractices.Thefollowingshallbenoted:locationsofBMPsinspected,locationsofBMPsthatneedmaintenance,thereasonmaintenanceisneeded,locationsofBMPsthatfailedtooperateasdesignedorintended,andlocationswhereadditionalordifferentBMPsareneeded,andthereason(s)whyAdescriptionofstormwaterdischargedfromthesite.Thepresenceofsuspendedsediment,turbidwater,discoloration,and/oroilsheenshallbenoted,asapplicable.Adescriptionofanywaterqualitymonitoringperformedduringinspection,andtheresultsofthatmonitoring.Generalcommentsandnotes,includingabriefdescriptionofanyBMPrepairs,maintenanceorinstallationsmadeasaresultoftheinspection.Astatementthat,inthejudgmentofthepersonconductingthesiteinspection,thesiteiseitherincomplianceoroutofcompliancewiththetermsandconditionsoftheSWPPPandtheNPDESpermit.Ifthesiteinspectionindicatesthatthesiteisoutofcompliance,theinspectionreportshallincludeasummaryoftheremedialactionsrequiredtobringthesitebackintocompliance,aswellasascheduleofimplementation.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageD-1 Name,title,andsignatureofpersonconductingthesiteinspection;andthefollowingstatement:‘Clcertifyunderpenaltyoflawthatthisreportistrue,accurate,andcomplete,tothebestofmyknowledgeandbelief”.WhenthesiteinspectionindicatesthatthesiteisnotincompliancewithanytermsandconditionsoftheNPDESpermit,thePermitteeshalltakeimmediateaction(s)to:stop,contain,andcleanuptheunauthorizeddischarges,orotherwisestopthenoncompliance;correcttheproblem(s);implementappropriateBestManagementPractices(BMPs),and/orconductmaintenanceofexistingEMPs;andachievecompliancewithallapplicablestandardsandpermitconditions.Inaddition,ifthenoncompliancecausesathreattohumanhealthortheenvironment,thePermitteeshallcomplywiththeNoncomplianceNotificationrequirementsinSpecialConditionS5.Fofthepermit.D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageD-2 ConstructionStormwaterSiteInspectionFormProjectName______________ _______Permit#:_______ ____ ____ _NameofCertifiedErosionSedimentControlLead(CESCL)orqualifiedinspectoriflessthanoneacrePrintName:Approximaterainfallamountsincethelastinspection(ininches):____________ _____ _____ ________Approximaterainfallamountinthelast24hours(ininches):______ _______ _____ _______ ____CurrentWeatherClearCloudyMistRainWindFogA.Typeofinspection:WeeklyDPostStormEventOtherB.PhaseofActiveConstruction(checkallthatapply):PreConstruction/installationoferosion/sedimentcontrolsClearing/Demo/GradingInfrastructure/storm/roadsConcretepoursVerticalConstruction/buildingsUtilitiesOffsiteimprovementsSitetemporarystabilizedFinalstabilizationC.Questions:1.Wereallareasofconstructionanddischargepointsinspected?2.Didyouobservethepresenceofsuspendedsediment,turbidity,discoloration,oroilsheen3.Wasawaterqualitysampletakenduringinspection?(refertopermitconditions54&55)4.Wasthereaturbiddischarge250NTUorgreater,orTransparency6cmorless?*5.Ifyesto#4wasitreportedtoEcology?6.IspHsamplingrequired?pHrangerequiredis6.5to8.5.YesNoYesNoYesNoYesNoYesNoYesNoIfansweringyestoadischarge,describetheevent.Includewhen,where,andwhyithappened;whatactionwastaken,andwhen.*lfansweringyesto#4recordNTU/Transparencywithcontinualsamplingdailyuntilturbidityis25NTUorless!transparencyis33cmorgreater.SamplingResults:Date:ParameterMethod(circleone)ResultOther/NoteNTUcmpHTurbiditytube,meter,laboratorypHPaper,kit,meterD.R.STRONGConsultingEngineers,Inc.StormwaterPollutionPreventionPlanVuecrestEstates&VuecrestIIShortPlatDate:Time:PageD-3 ConstructionStormwaterSiteInspectionFormD.Checktheobservedstatusofallitems.Provide“ActionRequired“detailsanddates.Element#InspectionBMPsBMPneedsBMPActionrequiredInspectedmaintenancefailed(describein-;—-:;“--;j-sectionF)1BeforebeginninglanddisturbingClearingactivitiesareallclearinglimits,naturalLimitsresourceareas(streams,wetlands,buffers,trees)protectedwithbarriersorsimilarBMPs?(highvisibilityrecommended)2ConstructionaccessisstabilizedwithConstructionquarryspallsorequivalentBMPtoAccesspreventsedimentfrombeingtrackedontoroads?Sedimenttrackedontotheroadwaywascleanedthoroughlyattheendofthedayormorefrequentasnecessary.3AreflowcontrolmeasuresinstalledtoControlFlowcontrolstormwatervolumesandRatesvelocityduringconstructionanddotheyprotectdownstreampropertiesandwaterwaysfromerosion?Ifpermanentinfiltrationpondsareusedforflowcontrolduringconstruction,aretheyprotectedfromsiltation?4Allperimetersedimentcontrols(e.g.Sedimentsiltfence,wattles,compostsocks,Controlsberms,etc.)installed,andmaintainedinaccordancewiththeStormwaterPollutionPreventionPlan(SWPPP).SedimentcontrolBMPs(sedimentponds,traps,filtersetc.)havebeenconstructedandfunctionalasthefirststepofgrading.StormwaterrunofffromdisturbedareasisdirectedtosedimentremovalBMP.5Haveexposedun-workedsoilsbeenStabilizeSoilsstabilizedwitheffectiveBMPtopreventerosionandsedimentdeposition?Arestockpilesstabilizedfromerosion,protectedwithsedimenttrappingmeasuresandlocatedawayfromdraininlet,waterways,anddrainagechannels?Havesoilsbeenstabilizedattheendoftheshift,beforeaholidayorweekendifneededbasedontheweatherforecast?D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPtatStormwaterPollutionPreventionPlanPageD-4 ConstructionStormwaterSiteInspectionFormElement#InspectionBMPsInspectedBMPneedsBMPActionrequired—maintenancefailed(describeinyesnon/asection_F)6HasstormwaterandgroundwaterProtectbeendivertedawayfromslopesandSlopesdisturbedareaswithinterceptordikes,pipesandorswales?Isoff-sitestormwatermanagedseparatelyfromstormwatergeneratedonthesite?Isexcavatedmaterialplacedonuphillsideoftrenchesconsistentwithsafetyandspaceconsiderations?Havecheckdamsbeenplacedatregularintervalswithinconstructedchannelsthatarecutdownaslope?7StormdraininletsmadeoperableDrainInletsduringconstructionareprotected.Areexistingstormdrainswithintheinfluenceoftheprojectprotected?8Haveallon-siteconveyancechannelsStabilizebeendesigned,constructedandChannelandstabilizedtopreventerosionfromOutletsexpectedpeakflows?Isstabilization,includingarmoringmaterial,adequatetopreventerosionofoutlets,adjacentstreambanks,slopesanddownstreamconveyancesystems?9ArewastematerialsanddemolitionControldebrishandledanddisposedoftoPollutantspreventcontaminationofstormwater?Hascoverbeenprovidedforallchemicals,liquidproducts,petroleumproducts,andothermaterial?Hassecondarycontainmentbeenprovidedcapableofcontaining110%ofthevolume?Werecontaminatedsurfacescleanedimmediatelyafteraspillincident?WereBMPsusedtopreventcontaminationofstormwaterbyapHmodifyingsources?Wheelwashwastewaterishandledanddisposedofproperly.10Concretewashoutindesignatedareas.ControlNowashoutorexcessconcreteontheDewateringground.DewateringhasbeendonetoanapprovedsourceandincompliancewiththeSWPPP.Werethereanycleannonturbiddewateringdischarges?D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageD-5 ConstructionStormwaterSiteInspectionFormElement#InspectionBMPslnspectedBMPneedsBMPActionrequiredyesnon/amaintenancefailed(describeinsection_F)11ArealltemporaryandpermanentMaintainerosionandsedimentcontrolBMPsBMPmaintainedtoperformasintended?12HastheprojectbeenphasedtotheManagethemaximumdegreepracticable?ProjectHasregularinspection,monitoringandmaintenancebeenperformedasrequiredbythepermit?HastheSWPPPbeenupdated,implementedandrecordsmaintained?E.Checkallareasthathavebeeninspected.v’AllinplaceBMPsAlldischargelocationsAlldisturbedsoilsAllmaterialstorageareasDAllconcretewashoutareasDAllequipmentstorageareasDAllconstructionentrances/exitsF.Elementschecked“ActionRequired”(sectionD)describecorrectiveactiontobetaken.Listtheelementnumber;bespecificonlocationandworkneeded.Document,initial,anddatewhenthecorrectiveactionhasbeencompletedandinspected.ElementDescriptionandLocationActionRequiredCompletionInitials#DateAttachadditionalpageifneededSignthefollowingcertification:“Icertifythatthisreportistrue,accurate,andcomplete,tothebestofmyknowledgeandbelief”Inspectedby:PrintSignatureTitle/QualificationofInspectorDateD.R.STRONGConsultingEngineers,Inc.StormwaterPollutionPreventionPlanVuecrestEstates&VuecrestIIShortPlatPageD-6 AppendixEConstructionStormwaterGeneralPermit(CSWGP)_____D.R.STRONGConsultingEngineers,Inc.VuecrestEstates&VuecrestIIShortPlatStormwaterPollutionPreventionPlanPageF-2 IssuanceDate:December1,2010EffectiveDate:January1,2011ExpirationDate:December31,2015CONSTRUCTIONSTORNIWATERGENERALPERMITNationalPollutantDischargeEliminationSystem(NPDES)andStateWasteDischargeGeneralPermitforStormwaterDischargesAssociatedwithConstructionActivity.StateofWashingtonDepartmentofEcologyOlympia,Washington92504IncompliancewiththeprovisionsofChapter90.48RevisedCodeofWashington(StateofWashingtonWaterPollutionControlAct)andTitle33UnitedStatesCode,Section1251etseq.TheFederalWaterPollutionControlAct(TheCleanWaterAct)Untilthispermitexpires,ismodifiedorrevoked,Permitteesthathaveproperlyobtainedcoverageunderthisgeneralpermitareauthorizedtodischargeinaccordancewiththespecialandgeneralconditionsthatfollow./41’Susewind,P.E.,P.G.7WaterQualityProgramManagerWashingtonStateDepartmentofEcology TABLEOfCONTENTSL1STOFTABLES3SPECIALCONDITIONS5S1.PERMITCOVERAGE5S2.APPLICATIONREQUIREMENTS8S3.COMPLIANCEWITHSTANDARDS11S4.MONITORiNGREQUIREMENTS12$5.REPORTINGANDRECORDKEEPTNGREQUIREMENTS1956.PERMITFEES2257.SOLIDANDLIQUIDWASTEDISPOSAL2258.DISCHARGESTO303(D)ORTMDLWATERBODIES2259.STORMWATERPOLLUTIONPREVENTIONPLAN26510.NOTICEOfTERMINATION34GENERALCONDITIONS36Gi.DISCHARGEVIOLATIONS36G2.SIGNATORYREQUIREMENTS36G3.RIGHTOfNSPECTIONANDENTRY37G4.GENERALPERMITMODIFICATIONANDREVOCATION37G5.REVOCATIONOfCOVERAGEUNDERThEPERMIT37G6.REPORTINGACAUSEFORMODIFICATION38G7.COMPLIANCEWITHOTHERLAWSANDSTATUTES38G8.DUTYTOREAPPLY38G9.TRANSFEROfGENERALPERMITCOVERAGE39Gb.REMOVEDSUBSTANCES39Gil.DUTYTOPROVIDEINFORMATION39G12.OTHERREQUIREMENTSOf40CfR39Gi3.ADDITIONALMONITORING39G14.PENALTIESFORVIOLATiNGPERMITCONDITIONS40G15.UPSET40ConstructionStorrnwaterGeneralPermit—December1,2010Page2 G16.PROPERTYRIGHTS40G17.DUTYTOCOMPLY40G18.TOXICPOLLUTANTS41G19.PENALTIESFORTAMPERING41G20.REPORTINGPLANNEDCHANGES41G21.REPORTINGOTHERINFORMATION42G22.REPORTINGANTICIPATEDNON-COMPLIANCE42G23.REQUESTSTOBEEXCLUDEDFROMCOVERAGEUNDERTHEPERMIT42G24.APPEALS42G25.SEVERABILITY43G26.BYPASSPROHIBITED43APPENDIXA-DEFINITIONS46APPENDIXB-ACRONYMS54LISTOFTABLESTable1.SummaryofPermitReportSubmittals4Table2.SummaryofRequiredOn-siteDocumentation4Table3.SummaryofPrimaryMonitoringRequirements12Table4.MonitoringandReportingRequirements16Table5.Turbidity,FineSediment&PhosphorusSamplingandLimitsfor303(d)-Listed...24Table6.pHSamplingandLimitsfor303(d)-ListedWaters24ConstructionStormwaterGeneralPermit—December1,2010Page3 SUMMARYOfPERMITREPORTSUBMITTALSRefertotheSpecialandGeneralConditionswithinthispermitforadditionalsubmittalrequirements.AppendixAprovidesalistofdefinitions.AppendixBprovidesalistofacronyms.TableISummaryofPermitReportSubmittalsPermitSubmittalFrequencyFirstSubmittalDateSectionS5.AandHighTurbidity/TransparencyPhoneAsNecessaryWithin24hours58Reporting55.8DischargeMonitoringReportMonthly*Within15daysofapplicablemonitoringperiodS5.FandNoncomplianceNotificationAsnecessaryImmediately58S5.FNoncomplianceNotification—AsnecessaryWithin5Daysofnon-WrittenReportcomplianceG2.NoticeofChangeinAuthorizationAsnecessaryG6.PermitApplicationforSubstantiveAsnecessaryChangestotheDischargeG8.ApplicationforPermitRenewal1/permitcycleNolaterthan180daysbeforeexpirationG9.NoticeofPermitTransferAsnecessaryG20.NoticeofPlannedChangesAsnecessaryG22.ReportingAnticipatedNon-AsnecessarycomplianceSPECIALNOTE:*pejtteesmustsubmitDischargeMonitoringReports(DMRs)totheWashingtonStateDepartmentofEcologymonthly,regardlessofsitedischarge,forthefulldurationofpermitcoverage.RefertoSectionS5.BofthisGeneralPermitformorespecificinformationregardingDMRs.Table2.SummaryofRequiredOn-siteDocumentationDocumentTitlePermitConditionsPermitCoverageLetterSeeConditions52,S5ConstructionStormwaterGeneralPermitSeeConditions52,55SiteLogBookSeeConditions54,55StormwaterPollutionPreventionPlan(SWPPP)SeeConditions59,55ConstructionStOl7nwaterGeneralPermit—December1,2010Page4 SPECIALCONDITIONSSi.PERMITCOVERAGEA.PermitAreaThisConstructionStormwaterGeneralPermit(CSWGP)coversallareasofWashingtonState,exceptforfederalandTriballandsasspecifiedinSpecialConditionS1.E.3.B.OperatorsRequiredtoSeekCoverageUnderthisGeneralPermit:1.OperatorsofthefollowingconstructionactivitiesarerequiredtoseekcoverageunderthisCSWGP:a.Clearing,gradingand/orexcavationthatresultsinthedisturbanceofoneormoreacresanddischargesstormwatertosurfacewatersoftheState;andclearing,gradingand/orexcavationonsitessmallerthanoneacrethatarepartofalargercommonplanofdevelopmentorsale,ifthecommonplanofdevelopmentorsalewillultimatelydisturboneacreormoreanddischargestorrnwatertosurfacewatersoftheState.i.Thisincludesforestpractices(including,butnotlimitedto,classIVconversions)thatarepartofaconstructionactivitythatwillresultinthedisturbanceofoneormoreacres,anddischargetosurfacewatersoftheState(thatis,forestpracticesthatprepareasiteforconstructionactivities);andb.AnysizeconstructionactivitydischargingstormwatertowatersoftheStatethattheDepartmentofEcology(“Ecology”):i.DeterminestobeasignificantcontributorofpollutantstowatersoftheStateofWashington.ii.Reasonablyexpectstocauseaviolationofanywaterqualitystandard.2.OperatorsofthefollowingactivitiesarenotrequiredtoseekcoverageunderthisC$WGP(unlessspecificallyrequiredunderSpecialConditionSi.B.1.b.above):a.Constructionactivitiesthatdischargeallstormwaterandnon-storrnwatertogroundwater,sanitarysewer,orcombinedsewer,andhavenopointsourcedischargetoeithersurfacewaterorastormsewersystemthatdrainstosurfacewatersoftheState.b.ConstructionactivitiescoveredunderanErosivityWaiver(SpecialConditionS2.C).c.Routinemaintenancethatisperformedtomaintaintheoriginallineandgrade,hydrauliccapacity,ororiginalpurposeofafacility.ConstructionStormwaterGeneralPermit—December1,2010Page5 C.AuthorizedDischarges:1.StorrnwaterAssociatedwithConstructionActivity.Subjecttocompliancewiththetemsandconditionsofthispermit.PermitteesareauthorizedtodischargestorrnwaterassociatedwithconstructionactivitytosurfacewatersoftheStateortoastormsewersystemthatdrainstosurfacewatersoftheState.(Notethat“surfacewatersoftheState”mayexistonaconstructionsiteaswellasoffsite;forexample,acreekrunningthroughasite.)2.StormwaterAssociatedwithConstructionSupportActivity.Thispermitalsoauthorizesstorrnwaterdischargefromsupportactivitiesrelatedtothepermittedconstructionsite(forexample,anon-siteportablerockcrusher,off-siteequipmentstagingyards,materialstorageareas,borrowareas,etc.)provided:a.ThesupportactivityrelatesdirectlytothepermittedconstructionsitethatisrequiredtohaveaNPDESpermit;andb.Thesupportactivityisnotacommercialoperationservingmultipleunrelatedconstructionprojects,anddoesnotoperatebeyondthecompletionoftheconstructionactivity;andC.AppropriatecontrolsandmeasuresareidentifiedintheStormwaterPollutionPreventionPlan(SWPPP)forthedischargesfromthesupportactivityareas.3.Non-StormwaterDischarges.Thecategoriesandsourcesofnon-stormwaterdischargesidentifiedbelowareauthorizedconditionally,providedthedischargeisconsistentwiththetermsandconditionsofthispermit:a.Dischargesfromfire-fightingactivities.b.Firehydrantsystemflushing.C.Potablewater,includinguncontaminatedwaterlineflushing.d.Pipelinehydrostatictestwater.e.Uncontaminatedairconditioningorcompressorcondensate.f.Uncontaminatedgroundwaterorspringwater.g.Uncontaminatedexcavationdewateñngwater(inaccordancewithS9.D.1O).h.Uncontaminateddischargesfromfoundationorfootingdrains.i.Waterusedtocontroldust.Permitteesmustminimizetheamountofdustcontrolwaterused.j.Routineexternalbuildingwashdownthatdoesnotusedetergents.k.Landscapeirrigationwater.TheSWPPPmustadequatelyaddressallauthorizednon-stormwaterdischarges,exceptfordischargesfromfire-fightingactivities,andmustcomplywithSpecialConstructionStormwaterGeneralPermit—December1,2010Page6 ConditionS3.Ataminimum,dischargesfrompotablewater(includingwaterlineflushing),firehydrantsystemflushing,andpipelinehydrostatictestwatermustundergothefollowing:dechlorinationtoaconcentrationofO.1partspermillion(ppm)orless,andpHadjustmenttowithin6.5—8.5standardunits(su),ifnecessary.D.ProhibitedDischarges:ThefollowingdischargestowatersoftheState,includinggroundwater,areprohibited.1.Concretewastewater.2.Wastewaterfromwashoutandclean-upofstucco,paint,fonnreleaseoils,curingcompoundsandotherconstructionmaterials.3.Processwastewaterasdefinedby40CodeoffederalRegulations(CFR)122.1(seeAppendixAofthispermit).4.Slurrymaterialsandwastefromshaftdrilling.5.Fuels,oils,orotherpollutantsusedinvehicleandequipmentoperationandmaintenance.6.Soapsorsolventsusedinvehicleandequipmentwashing.7.Wheelwashwastewater,unlessdischargedaccordingtoSpecialCondition59.D.9.d.8.Dischargesfromdewateringactivities,includingdischargesfromdewateringoftrenchesandexcavations,unlessmanagedaccordingtoSpecialConditionS9.D.10.E.LimitsonCoverageEcologymayrequireanydischargertoapplyforandobtaincoverageunderanindividualpermitoranothermorespecificgeneralpermit.SuchalternativecoveragewillberequiredwhenEcologydeterminesthatthisCSWGPdoesnotprovideadequateassurancethatwaterqualitywillbeprotected,orthereisareasonablepotentialfortheprojecttocauseorcontributetoaviolationofwaterqualitystandards.Thefollowingstormwaterdischargesarenotcoveredbythispermit:1.Post-constructionstormwaterdischargesthatoriginatefromthesiteaftercompletionofconstructionactivitiesandthesitehasundergonefinalstabilization.2.Non-pointsourcesilviculturalactivitiessuchasnurseryoperations,sitepreparation,reforestationandsubsequentculturaltreatment,thinning,prescribedburning,pestandfirecontrol,harvestingoperations,surfacedrainage,orroadconstructionandmaintenance,fromwhichthereisnaturalrunoffasexcludedin40CFRSubpart122.3.StorrnwaterfromanyfederalprojectorprojectonfederallandorlandwithinanIndianReservationexceptforthePuyallupReservation.WithinthePuyallupConstructionStol7nwaterGeneralPermit—December1,2010Page7 Reservation,anyprojectthatdischargestosurfacewateronlandheldintrustbythefederalgovernmentmaybecoveredbythispermit.4.StonwaterfromanysitecoveredunderanexistingNPDESindividualpermitinwhichstonwatermanagementand/ortreatmentrequirementsareincludedforallstonrnvaterdischargesassociatedwithconstructionactivity.5.StormwaterfromasitewhereanapplicableTotalMaximumDailyLoad(TMDL)requirementspecificallyprecludesorprohibitsdischargesfromconstructionactivity.S2.APPLICATIONREQUIREMENTSA.PermitApplicationForms1.NoticeofIntentFonm’Tirnelinea.Operatorsofneworpreviouslyunpermittedconstructionactivitiesmustsubmitacompleteandaccuratepermitapplication(NoticeofIntent,orNOl)toEcology.b.TheoperatormustsubmittheNOlatleast60daysbeforedischargingstormwaterfromconstructionactivitiesandmustsubmititonorbeforethedateofthefirstpublicnotice(seeSpecialConditionS2.Bbelowfordetails).The30-daypubliccommentperiodrequiredbyWAC173-226-130(5)beginsonthepublicationdateofthesecondpublicnotice.UnlessEcologyrespondstothecompleteapplicationinwriting,basedonpubliccomments,oranyotherrelevantfactors,coverageunderthegeneralpermitwillautomaticallycommenceonthethirty-firstdayfollowingreceiptbyEcologyofacompletedNOI,ortheissuancedateofthispermit,whicheverislater,unlessEcologyspecifiesalaterdateinwriting.C.ApplicantswhoproposetodischargetoastormorsewersystemoperatedbySeattle,KingCounty,SnohomishCounty,Tacoma,PierceCounty,orClarkCountymustalsosubmitacopyoftheNOltotheappropriatejurisdiction.d.IfanapplicantintendstouseaBestManagementPractice(BMP)selectedonthebasisofSpecialConditionS9C.4(“demonstrablyequivalent”BMPs),theapplicantmustnotifyEcologyofitsselectionaspartoftheNOl.IntheeventtheapplicantselectsBMPsaftersubmissionoftheNOI,itmustprovidenoticeoftheselectionofanequivalentBMPtoEcologyatleast60daysbeforeintendeduseoftheequivalentBMP.e.PermitteesmustnotifyEcologyregardinganychangestotheinformationprovidedontheNOlbysubmittinganupdatedNOl.Examplesofsuchchangesinclude,butarenotlimitedto,i.changestothePermittee’smailingaddress,ii.changestotheon-sitecontactpersoninformation,andConstructionStorrnwaterGeneralPermit—December1,2010Page8 iii.changestothearea/acreageaffectedbyconstructionactivity.2.TransferofCoverageformThePermitteecantransfercurrentcoverageunderthispermittooneormorenewoperators,includingoperatorsofsiteswithinaCommonPlanofDevelopment,providedthePermitteesubmitsaTransferofCoverageforminaccordancewithGeneralConditionG9.Transfersdonotrequirepublicnotice.B.PublicNoticeforneworpreviouslyunpennittedconstructionactivities,theapplicantmustpublishapublicnoticeatleastonetimeeachweekfortwoconsecutiveweeks,atleast7daysapart,inanewspaperwithgeneralcirculationinthecountywheretheconstructionistotakeplace.Thenoticemustcontain:1.Astatementthat“TheapplicantisseekingcoverageundertheWashingtonStateDepartmentofEcology’sConstructionStormwaterNPDESandStateWasteDischargeGeneralPermit.”2.Thename,addressandlocationoftheconstructionsite.3.Thenameandaddressoftheapplicant.4.Thetypeofconstructionactivitythatwillresultinadischarge(forexample,residentialconstruction,commercialconstruction,etc.),andthenumberofacrestobedisturbed.5.Thenameofthereceivingwater(s)(thatis,thesurfacewater(s)towhichthesitewilldischarge),or,ifthedischargeisthroughastormsewersystem,thenameoftheoperatorofthesystem.6.Thestatement:“AnypersonsdesiringtopresenttheirviewstotheWashingtonStateDepartmentofEcologyregardingthisapplication,orinterestedinEcology’sactiononthisapplication,maynotifyEcologyinwritingnolaterthan30daysofthelastdateofpublicationofthisnotice.Ecologyreviewspubliccommentsandconsiderswhetherdischargesfromthisprojectwouldcauseameasurablechangeinreceivingwaterquality,and,ifso,whethertheprojectisnecessaryandintheoverridingpublicinterestaccordingtoTierIIantidegradationrequirementsunderWAC173-201A-320.Commentscanbesubmittedto:DepartmentofEcology,P.O.Box47696,Olympia,WA98504-7696Atm:WaterQualityProgram,ConstructionStormwater.”ConstructionStol7nwaterGeneralPermit—December1,2010Page9 C.ErosivityWaiverConstructionsiteoperatorsmayqualifyforanerosivitywaiverfromtheCSWGPifthefollowingconditionsaremet:I.Thesitewillresultinthedisturbanceoffewerthan5acresandthesiteisnotaportionofacommonplanofdevelopmentorsalethatwilldisturb5acresorgreater.2.CalculationofErosivity“R”FactorandRegionalTimeframe:a.Theproject’srainfallerosivityfactor(“R”Factor)mustbelessthan5duringtheperiodofconstructionactivity,ascalculatedusingeithertheTexasA&MUniversityonlinerainfallerosivitycalculatorat:http://ei.tamu.edu/orEPA’scalculatorathttp://cfpub.epa.ov/npdes/stormwater/1ew/lewcalcu1ator.cfntTheperiodofconstructionactivitystartswhenthelandisfirstdisturbedandendswithfinalstabilization.Inaddition:b.Theentireperiodofconstructionactivitymustfallwithinthefollowingtimeframes:i.ForsiteswestoftheCascadesCrest:June15—September15.ii.forsiteseastoftheCascadesCrest,excludingtheCentralBasin:June15—October15.iii.forsiteseastoftheCascadesCrest,withintheCentralBasin:noadditionaltimeframerestrictionsapply.TheCentralBasinisdefinedastheportionsofEasternWashingtonwithmeanannualprecipitationoflessthan12inches.ForamapoftheCentralBasin(Region2),refertohttp://www.ecy.wa.gov/pubs/ecy070202.pdf.3.ConstructionsiteoperatorsmustsubmitacompleteErosivityWaivercertificationformatleastoneweekbeforedisturbingtheland.Certificationmustincludestatementsthattheoperatorwill:a.Complywithapplicablelocalstormwaterrequirements;andb.ImplementappropriateerosionandsedimentcontrolBMPstopreventviolationsofwaterqualitystandards.4.ThiswaiverisnotavailableforfacilitiesdeclaredsignificantcontributorsofpollutantsasdefinedinSpecialConditionS1.B.1.b.5*Thiswaiverdoesnotapplytoconstructionactivitieswhichincludenon-stormwaterdischargeslistedinSpecialConditionSl.C.3.6.Ifconstructionactivityextendsbeyondthecertifiedwaiverperiodforanyreason,theoperatormusteither:a.Recalculatetherainfallerosivity“R”factorusingtheoriginalstartdateandanewprojectedendingdateand,ifthe“R”factorisstillunder5jictheentireConstructionStorrnwaterGeneralPermit—December1,2010Page10 projectfallswithintheapplicableregionaltimeframeinSpecialConditionS2.C.2.b,completeandsubmitanamendedwaivercertificationformbeforetheoriginalwaiverexpires;orb.SubmitacompletepermitapplicationtoEcologyinaccordancewithSpecialConditionS2.AandBbeforetheendofthecertifiedwaiverperiod.$3.COMPLIANCEWITHSTANDARDSA.Dischargesmustnotcauseorcontributetoaviolationofsurfacewaterqualitystandards(Chapter173-201AWAC),groundwaterqualitystandards(Chapter173-200WAC).sedimentmanagementstandards(Chapter173-204WAC),andhumanhealth-basedcriteriaintheNationalToxicsRule(40CFRPart131.36).Dischargesnotincompliancewiththesestandardsarenotauthorized.B.Priortothedischargeofstorrnwaterandnon-storrnwatertowatersoftheState,thePermitteemustapplyallknown,available,andreasonablemethodsofprevention,control,andtreatment(AKART).ThisincludesthepreparationandimplementationofanadequateStorrnwaterPollutionPreventionPlan(SWPPP),withallappropriateBMPsinstalledandmaintainedinaccordancewiththeSWPPPandthetermsandconditionsofthi.spennit.C.EcologypresumesthataPermitteecomplieswithwaterqualitystandardsunlessdischargemonitoringdataorothersite-specificinformationdemonstratesthatadischargecausesorcontributestoaviolationofwaterqualitystandards,whenthePermitteecomplieswiththefollowingconditions.ThePermifteemustfully:1.Complywithallpenriitconditions,includingplanning,sampling,monitoring,reporting,andrecordkeepingconditions.2.ImplementstormwaterBMPscontainedinstormwatermanagementmanualspublishedorapprovedbyEcology,orBMPsthataredemonstrablyequivalenttoBMPscontainedinstormwatertechnicalmanualspublishedorapprovedbyEcology,includingtheproperselection,implementation,andmaintenanceofallapplicableandappropriateBMPsforon-sitepollutioncontrol.(forpurposesofthissection,thestormwatermanualslistedinAppendix10ofthePhaseIMunicipalStormwaterPermitareapprovedbyEcology.)D.Whereconstructionsitesalsodischargetogroundwater,thegroundwaterdischargesmustalsomeetthetermsandconditionsofthisCSWGP.PermitteeswhodischargetogroundwaterthroughaninjectionwellmustalsocomplywithanyapplicablerequirementsoftheUndergroundInjectionControl(UIC)regulations,Chapter173-218WAC.ConstructionStonnwaterGeneralPermit—December1,2010Page11 S4.MONITORiNGREQUIREMENTS,BENCHMARKSANDREPORTINGTRIGGERSTable3.SummaryofPrimaryMonitoringRequirementsA.SiteLogBookThePermitteemustmaintainasitelogbookthatcontainsarecordoftheimplementationoftheSWPPPandotherpermitrequirements,includingtheinstallationandmaintenanceofBMPs,siteinspections,andstormwatermonitoring.B.SiteInspectionsThePermittee’s(operator’s)siteinspectionsmustincludeallareasdisturbedbyconstructionactivities,allBMPs,andallstorrnwaterdischargepoints.(SeeSpecialConditions54.B.3andB.4belowfordetailedrequirementsofthePermittee’sCertifiedErosionandSedimentControlLead[CESCL]).1Soildisturbanceiscalculatedbyaddingtogetherallareasaffectedbyconstructionactivity.Constructionactivitymeansclearing,grading,excavation,andanyotheractivitythatdisturbsthesurfaceoftheland,includingingress/egressfromthesite.2Ifconstructionactivityresultsinthedisturbanceof1acreormore,andinvolvessignificantconcretework(1,000cubicyardsofpouredorrecycledconcreteoverthelifeofaproject)ortheuseofengineeredsoils(soilamendmentsincludingbutnotlimitedtoPortlandcement-treatedbase[CTB],cementkilndust[CKD],orflyash),andstormwaterfromtheaffectedareadrainstosurfacewatersoftheStateortoastormsewerstormwatercollectionsystemthatdrainstoothersurfacewatersoftheState,thePermitteemustconductpHmonitoringsamplinginaccordancewithSpecialConditionS4.D.3Siteswithoneormoreacres,butfewerthan5acresofsoildisturbance,mustconductturbidityortransparencysamplinginaccordancewithSpecialConditionS4.C.4Sitesequaltoorgreaterthan5acresofsoildisturbancemustconductturbiditysamplingusingaturbiditymeterinaccordancewithSpecialConditionS4.C.ConstructionStormwaterGeneralPermit—December1,2010Page12SizeofSoilWeeklySiteWeeklyWeeklyWeeklypHRequiresDisturbance1InspectionsSamplingwISamplingwISampling2CESCLTurbidityTransparencyCertification?MeterTubeSitesthatdisturbRequiredNotRequiredNotRequiredNotRequiredNolessthanIacre,butarepartofalargerCommonPlanofDevelopmentSitesthatdisturbIRequiredSamplingRequired—RequiredYesacreormore,buteithermethodfewerthan5acresSitesthatdisturb5RequiredRequiredNotRequired4RequiredYesacresormore ConstructionsitesoneacreorlargerthatdischargestormwatertosurfacewatersoftheStatemusthavesiteinspectionsconductedbyacertifiedCESCL.SiteslessthanoneacremayhaveapersonwithoutCESCLcertificationconductinspections;samplingisnotrequiredonsitesthatdisturblessthananacre.1.ThePermitteemustexaminestormwatervisuallyforthepresenceofsuspendedsediment.turbidity,discoloration,andoilsheen.ThePermitteemustevaluatetheeffectivenessofBMPsanddetermineifitisnecessarytoinstall,maintain,orrepairBMPstoimprovethequalityofstorrnwaterdischarges.Basedontheresultsoftheinspection,thePermitteemustcorrecttheproblemsidentifiedby:a.ReviewingtheSWPPPforcompliancewithSpecialConditionS9andmakingappropriaterevisionswithin7daysoftheinspection.b.Immediatelybeginningtheprocessoffullyimplementingandmaintainingappropriatesourcecontroland/ortreatmentBMPsassoonaspossible,addressingtheproblemsnolaterthanwithin10daysoftheinspection.IfinstallationofnecessarytreatmentBMPsisnotfeasiblewithin10days,EcologymayapproveadditionaltimewhenanextensionisrequestedbyaPermitteewithintheinitial10-dayresponseperiod.C.DocumentingBMPimplementationandmaintenanceinthesitelogbook.2.ThePermifteemustinspectallareasdisturbedbyconstructionactivities,allBMPs,andallstormwaterdischargepointsatleastonceeverycalendarweekandwithin24hoursofanydischargefromthesite.(Forpurposesofthiscondition,individualdischargeeventsthatlastmorethanonedaydonotrequiredailyinspections.Forexample,ifastormwaterponddischargescontinuouslyoverthecourseofaweek,onlyoneinspectionisrequiredthatweek.)ThePermitteemayreducetheinspectionfrequencyfortemporarilystabilized,inactivesitestoonceeverycalendarmonth.3.ThePermitteemusthavestaffknowledgeableintheprinciplesandpracticesoferosionandsedimentcontrol.TheCESCL(sitesoneacreormore)orinspector(siteslessthanoneacre)musthavetheskillstoassessthe:a.Siteconditionsandconstructionactivitiesthatcouldimpactthequalityofstorrnwater,andb.Effectivenessoferosionandsedimentcontrolmeasuresusedtocontrolthequalityofstormwaterdischarges.4.TheSWPPPmustidentifytheCESCLorinspector,whomustbepresentonsiteoron-callatalltimes.TheCESCLmustobtainthiscertificationthroughanapprovederosionandsedimentcontroltrainingprogramthatmeetstheminimumtrainingstandardsestablishedbyEcology(seeBMPCl60inthemanualreferredtoinSpecialConditionS9.C.1and2).ConstructionStormwaterGeneralPermit—December1,2010Page13 5.ThePermitteemustsummarizetheresultsofeachinspectioninaninspection::::.:reportorchecklistandenterthereport/checklistinto,orattachitto.thesitelog..z:..book.Ataminimum,eachinspectionreportorchecklistmustinclude::•••::a.inspectiondateandtime.b.Weatherinforniation,thegeneralconditionsduringinspectionandtheapproximateamountofprecipitationsincethelastinspection,andprecipitationwithinthelast24hours.c.AsummaryorlistofallimplementedBMPs,includingobservationsofallerosion/sedImentcontrolstructuresorpractices.d.Adescriptionofthelocations:i.OfBMPsinspected.ii.OfBMPsthatneedmaintenanceandwhy.iii.OfBMPsthatfailedtooperateasdesignedorintended,andiv.WhereadditionalordifferentBMPsareneeded,andwhy.e.Adescriptionofstormwaterdischargedfromthesite.ThePermitteemustnotethepresenceofsuspendedsediment,turbidity,discoloration,andoilsheen,asapplicable.f.Anywaterqualitymonitoringperformedduringinspection.g.Generalcommentsandnotes,includingabriefdescriptionofanyBMPrepairs,maintenanceorinstallationsmadefollowingtheinspection.h.AsummaryreportandascheduleofimplementationoftheremedialactionsthatthePermifteeplanstotakeifthesiteinspectionindicatesthatthesiteisoutofcompliance.TheremedialactionstakenmustmeettherequirementsoftheSWPPPandthepermit.i.Thename,title,andsignatureofthepersonconductingthesiteinspection,aphonenumberorotherreliablemethodtoreachthisperson,andthefollowingstatement:“Icertifythatthisreportistrue,accurate,andcompletetothebestofmyknowledgeandbelief.”C.Turbidity/TransparencySamplingRequirementsSamplingMethodsa.Ifconstructionactivityinvolvesthedisturbanceof5acresormore,thePermitteemustconductturbiditysamplingperSpecialConditionS4.C.b.Ifconstructionactivityinvolves1acreormorebutfewerthan5acresofsoildisturbance,thePermitteemustconducteithertransparencysamplingorturbiditysamplingperSpecialConditionS4.C.ConstructionStormwaterGeneralPermit—December1,2010Page14 2.SamplingFrequencya.ThePermitteemustsamplealldischargelocationsatleastonceeverycalendarieekwhenstorrnwater(orauthorizednon-storrnwater)dischargesfl-on;thesiteorentersanyon-sitesurfacewatersofthestate(forexample,acreekrunningthroughasite).b.Samplesmustberepresentativeoftheflowandcharacteristicsofthedischarge.c.Samplingisnotrequiredwhenthereisnodischargeduringacalendarweek.d.Samplingisnotrequiredoutsideofnormalworkinghoursorduringunsafeconditions.e.IfthePermitteeisunabletosan;pleduringamonitoringperiod,thePermitteemustincludeabriefexplanationinthemonthlyDischargeMonitoringReport(DMR).f.Samplingisnotrequiredbeforeconstructionactivitybegins.3.SamplingLocationsa.Samplingisrequiredatallpointswherestormwaterassociatedwithconstructionactivity(orauthorizednon-stormwater)isdischargedoffsite,includingwhereitentersanyon-sitesurfacewatersofthestate(forexample,acreekrunningthroughasite).b.ThePermitteemaydiscontinuesamplingatdischargepointsthatdrainareasoftheprojectthatarefullystabilizedtopreventerosion.C.ThePermitteemustidentifyallsamplingpoint(s)ontheSWPPPsitemapandclearlymarkthesepointsinthefieldwithaflag,tape,stakeorothervisiblemarker.d.Samplingisnotrequiredfordischargethatissentdirectlytosanitaryorcombinedsewersystems.4.SamplingandAnalysisMethodsa.ThePermitteeperformsturbidityanalysiswithacalibratedturbiditymeter(turbidimeter)eitheronsiteoratanaccreditedlab.ThePermitteemustrecordtheresultsinthesitelogbookinnephelornetricturbidityunits(NTU).b.ThePermitteeperformstransparencyanalysisonsitewitha1¾-inch-diameter,60-centimeter(cm)-longtransparencytube.ThePermifteewillrecordtheresultsinthesitelogbookincentimeters(cm).Transparencytubesareavailablefrom:http://watermonitoringequip.com/pageslstream.html.ConstructionStormwaterGeneralPermit—December1,2010Page15 Table4.MonitoringandReportingRequirementsParameterUnitAnalyticalMethodSamplingBenchmarkPhoneFrequencyValueReportingTriggerValueTurbidityNTUSM2130orEPAWeekly,if25NTU250NTU180.1dischargingTransparencycmManufacturerWeekly,if33cm6cminstructions,ordischargingEcologyguidance5.Turbidity/TransparencyBenchmarkValuesandReportingTriggersThebenchmarkvalueforturbidityis25NTUorless.Thebenchmarkvaluefortransparencyis33centimeters(cm).Note:BenchmarkvaluesdonotapplytodischargestosegmentsofwaterbodiesonWashingtonState’s303(d)list(Category5)forturbidity,finesediment,orphosphorus;thesedischargesaresubjecttoanumericeffluentlimitforturbidity.RefertoSpecialCondition$8formoreinformation.a.Turbidity26—249NTU.orTransparency32—7cm:Ifthedischargeturbidityis26to249NTU;orifdischargetransparencyislessthan33cm,butequaltoorgreaterthan6cm,thePermitteemust:i.ReviewtheSWPPPforcompliancewithSpecialCondition59andmakeappropriaterevisionswithin7daysofthedatethedischargeexceededthebenchmark.ii.Immediatelybegintheprocesstofullyimplementandmaintainappropriatesourcecontroland/ortreatmentBMPsassoonaspossible,addressingtheproblemswithin10daysofthedatethedischargeexceededthebenchmark.IfinstallationofnecessarytreatmentBMPsisnotfeasiblewithin10days,EcologymayapproveadditionaltimewhenthePermifteerequestsanextensionwithintheinitial10-dayresponseperiod.iii.DocumentBMPimplementationandmaintenanceinthesitelogbook.b.Turbidity250NTUorgreater,orTransparency6cmorless:Ifadischargepoint’sturbidityis250NTUorgreater,orifdischargetransparencyislessthanorequalto6cm,thePermilteemustcompletethereportingandadaptivemanagementprocessdescribedbelow.i.TelephonetheapplicableEcologyRegion’sEnvironmentalReportTrackingSystem(ERTS)numberwithin24hours,inaccordancewithSpecialConditionS5.F..CentralRegion(Okanogan,Chelan,Douglas,Kittitas,Yakima,Klickitat,Benton):(509)575-2490Constn.ictionStol7nwaterGeneralPermit—December1,2010Page16 .EasternRegion(Adams,Asotin,Columbia,FelTy,Franklin.Garfield,Grant,Lincoln,PendOreille.Spokane,Stevens.WallaWalla,Whitman):(509)329-3400.NorthwestRegion(Kitsap,Snohomish,island.King,SanJuan,Skagit,Whatcom):(425)649-7000.SouthwestRegion(GraysHarbor,Lewis,Mason,Thurston,Pierce,Clark,Cowlitz,Skarnania,Wahkiakurn,Clallam.Jefferson,Pacific):(360)407-6300Thesenumbersarealsolistedatthefollowingwebsite:http://wwwecywagov/programs/xvg/stormwater/constructionYpermit.htrnlii.ReviewtheSWPPPforcompliancewithSpecialConditionS9andmakeappropriaterevisionswithin7daysofthedatethedischargeexceededthebenchmark.iii.Immediatelybegintheprocesstofullyimplementandmaintainappropriatesourcecontroland/ortreatmentBMPsassoonaspossible,addressingtheproblemswithin10daysofthedatethedischargeexceededthebenchmark.IfinstallationofnecessarytreatmentBMPsisnotfeasiblewithin10days,EcologymayapproveadditionaltimewhenthePermitteerequestsanextensionwithintheinitial10-dayresponseperiod.iv.DocumentBMPimplementationandmaintenanceinthesitelogbook.v.Continuetosampledischargesdailyuntil:a)Turbidityis25NTU(orlower);orb)Transparencyis33cm(orgreater);orc)ThePermitteehasdemonstratedcompliancewiththewaterqualitylimitforturbidity:1)Nomorethan5NTUoverbackgroundturbidity,ifbackgroundislessthan50NTU,or2)Nomorethan10%overbackgroundturbidity,ifbackgroundis50NTUorgreater;ord)Thedischargestopsoriseliminated.D.pHSamplingRequirements--SignificantConcreteWorkorEngineeredSoilsIfconstructionactivityresultsinthedisturbanceof1acreormore,andinvolvessignificantconcretework(significantconcreteworkmeansgreaterthan1000cubicyardspouredconcreteorrecycledconcreteusedoverthelifeofaproject)ortheuseofengineeredsoils(soilamendmentsincludingbutnotlimitedtoPortlandcement-treatedbase[CTB],cementkilndust[CKDJ,orflyash),andstormwaterfromtheaffectedareaConstructionStorrnwaterGeneralPermit—December1,2010Page17 drainstosurfacewatersoftheStateortoastormsewersystemthatdrainstosurfacewatersofthestate,thePermitteemustconductpHmonitoringassetforthbelow.Note:Inaddition.dischargestosegmentsofwaterbodiesonWashingtonState’s303(d)list(Category5)forhighpHaresubjecttoanumericeffluentlimitforpH;refertoSpecialConditionS8.1.forsiteswithsignificantconcretework,thePermitteemustbeginthepHmonitoringperiodwhentheconcreteisfirstpouredandexposedtoprecipitation,andcontinueweeklythroughoutandaftertheconcretepourandcuringperiod,untilstormwaterpHisintherangeof6.5to8.5(su).2.Forsiteswithengineeredsoils,thePermitteemustbeginthepHmonitoringperiodwhenthesoilamendmentsarefirstexposedtoprecipitationandmustcontinueuntiltheareaofengineeredsoilsisfullystabilized.3.DuringtheapplicablepHmonitoringperioddefinedabove,thePermitteemustobtainarepresentativesampleofstormwaterandconductpHanalysisatleastonceperweek.4.ThePermitteemustmonitorpHinthesedimenttrap/pond(s)orotherlocationsthatreceivestormwaterrunofffromtheareaofsignificantconcreteworkorengineeredsoilsbeforethestonnwaterdischargestosurfacewaters.5.ThebenchmarkvalueforpHis8.5standardunits.AnytimesamplingindicatesthatpHis8.5orgreater,thePermitteemusteither:a.PreventthehighpHwater(8.5orabove)fromenteringstormsewersystemsorsurfacewaters;orb.Ifnecessary,adjustorneutralizethehighpHwateruntilitisintherangeofpH6.5to8.5(su)usinganappropriatetreatmentBMPsuchascarbondioxide(C02)spargingordryice.ThePennitteemustobtainwrittenapprovalfromEcologybeforeusinganyformofchemicaltreatmentotherthanCO2spargingordryice.6.ThePermilteemustperformpHanalysisonsitewithacalibratedpHmeter,pHtestkit,orwiderangepHindicatorpaper.ThePermitteemustrecordpHmonitoringresultsinthesitelogbook.ConstructionStorrnwaterGeneralPermit—December1,2010Page18 S5.REPORTiNGANDRECORDKEEPINGREQUiREMENTSA.HighTurbidityPhoneReportingAnytimesamplingperformedinaccordancewithSpecialCondition54.Cindicatesturbidityhasreachedthe250NTUphonereportinglevel,thePermitteemustcallEcology’sRegionalofficebyphonewithin24hoursofanalysis.Thewebsiteishttp://www.ecy.wa.gov/programs/wg!stormwater/construction!penmt.htrnl.AlsoseephonenumbersinSpecialConditionS4.C.5.b.i.B.DischargeMonitoringReportsPermitteesrequiredtoconductwaterqualitysamplinginaccordancewithSpecialConditionsS4.C(Turbidity/Transparency),S4.D(pH),S8(303[dJ/TMDLsampling),and/orG13(AdditionalSampling)mustsubmittheresultstoEcology.PermitteesmustsubmitmonitoringdatausingEcology’sWebDMRprogram.TofindoutmoreinformationandtosignupforWebDMRgoto:http://www.ecy.wa.gov/programs/wq/perrnits/paris/webdmr.html.Permitteesunabletosubmitelectronically(forexample,thosewhodonothaveanInternetconnection)mustcontactEcologytorequestawaiverandobtaininstructionsonhowtoobtainapapercopyDMRat:MailingAddress:DepartmentofEcologyWaterQualityProgramAttn:StormwaterComplianceSpecialistP0Box47696Olympia,WA98504-7696PermitteeswhoobtainawaivernottouseWebDMRmustusetheformsprovidedtothembyEcology;submittalsmustbemailedtotheaddressabove.PermitteesshallsubmitDMRformstobereceivedbyEcologywithin15daysfollowingtheendofeachmonth.Iftherewasnodischargeduringagivenmonitoringperiod,allPermitteesmustsubmitaDMRasrequiredwith“nodischarge”enteredinplaceofthemonitoringresults.formoreinformation,contactEcologystaffusinginformationprovidedatthefollowingwebsite:http://www.ecy.wa.gov/programs/spills/response/assistancesoil%20map.pdfC.RecordsRetentionThePennitteemustretainrecordsofallmonitoringinformation(sitelogbook,samplingresults,inspectionreports/checklists,etc.),StorrnwaterPollutionPreventionPlan,andanyotherdocumentationofcompliancewithpermitrequirementsfortheentirelifeoftheconstructionprojectandforaminimumofthreeyearsfollowingtheterminationofpermitcoverage.Suchinformationmustincludeallcalibrationandmaintenancerecords,andrecordsofalldatausedtocompletetheapplicationforthisConstructionStonnwaterGeneralPennit—December1,2010Page19 peiTnit.Thisperiodofretentionmustbeextendedduringthecourseofanyunresolved-litigationregardingthedischargeofpollutantsbythePermitteeorwhenrequestedby..Ecology.D.RecordingResultsforeachmeasurementorsampletaken,thePermitteemustrecordthefollowinginformation:1.Date,place,method,andtimeofsamplingormeasurement.2.Thefirstandlastnameoftheindividualwhoperformedthesamplingormeasurement.3.Thedate(s)theanalyseswereperformed.4.Thefirstandlastnameoftheindividualwhoperformedtheanalyses.5.Theanalyticaltechniquesormethodsused.6.Theresultsofallanalyses.E.AdditionalMonitoringbythePemiitteeIfthePermitteemonitorsanypollutantmorefrequentlythanrequiredbythispermitusingtestproceduresspecifiedbySpecialConditionS4ofthispermit,theresultsofthismonitoringmustbeincludedinthecalculationandreportingofthedatasubmittedinthePermittee’sDMR.F.NoncomplianceNotificationIntheeventthePermitteeisunabletocomplywithanypartofthetermsandconditionsofthispermit,andtheresultingnoncompliancemaycauseathreattohumanhealthortheenvironment,thePermifteemust:1.ImmediatelynotifyEcologyofthefailuretocomplybycallingtheapplicableRegionalofficeERTSphonenumber(findathp//www.ecy.wa.gov/programs/spills/response/assistancesoil%2Omap.pdf)orrefertoSpecialConditionS4.C.5.b.i.2.Immediatelytakeactiontopreventthedischarge/pollution,orotherwisestoporcorrectthenoncompliance,and,ifapplicable,repeatsamplingandanalysisofanynoncomplianceimmediatelyandsubmittheresultstoEcologywithinfive(5)daysofbecomingawareoftheviolation.3.SubmitadetailedwrittenreporttoEcologywithinfive(5)days,unlessrequestedearlierbyEcology.Thereportmustcontainadescriptionofthenoncompliance,includingexactdatesandtimes,andifthenoncompliancehasnotbeencorrected,theanticipatedtimeitisexpectedtocontinue;andthestepstakenorplannedtoreduce,eliminate,andpreventreoccurrenceofthenoncompliance.ConstructionStOl7flWaterGeneralPerinit—December1,2010Page20 ThePermitteemustreportanyunanticipatedbypassand/orupsetthatexceedsanyeffluentlimitinthepermitinaccordancewiththe24-hourreportingrequirementcontainedin40C.F.R.122.41(1)(6)).CompliancewiththeserequirementsdoesnotrelievethePermitteefromresponsibilitytomaintaincontinuouscompliancewiththetermsandconditionsofthispermitortheresultingliabilityforfailuretocomply.RefertoSectionG14ofthispermitforspecificinformationregardingnon-compliance.G.AccesstoPlansandRecords1.ThePermitteemustretainthefollowingpermitdocumentation(plansandrecords)onsite,orwithinreasonableaccesstothesite,forusebytheoperatororforon-sitereviewbyEcologyorthelocaljurisdiction:a.GeneralPermit.b.PermitCoverageLetter.C.StormwaterPollutionPreventionPlan(SWPPP).d.SiteLogBook.2.ThePermitteemustaddresswrittenrequestsforplansandrecordslistedabove(SpecialConditionS5.GA)asfollows:a.ThePermitteemustprovideacopyofplansandrecordstoEcologywithin14daysofreceiptofawrittenrequestfromEcology.b.ThePermifteemustprovideacopyofplansandrecordstothepublicwhenrequestedinwriting.UponreceivingawrittenrequestfromthepublicforthePermittee’Splansandrecords,thePermitteemusteither:i.Provideacopyoftheplansandrecordstotherequesterwithin14daysofareceiptofthewrittenrequest;orii.Notifytherequesterwithin10daysofreceiptofthewrittenrequestofthelocationandtimeswithinnormalbusinesshourswhentheplansandrecordsmaybeviewed;andprovideaccesstotheplansandrecordswithin14daysofreceiptofthewrittenrequest;orWithin14daysofreceiptofthewrittenrequest,thePennitteemaysubmitacopyoftheplansandrecordstoEcologyforviewingand/orcopyingbytherequesteratanEcologyoffice,oramutuallyagreedlocation.Ifplansandrecordsareviewedand/orcopiedatalocationotherthanatanEcologyoffice,thePennifteewillprovidereasonableaccesstocopyingservicesforwhichareasonablefeemaybecharged.ThePermitteemustnotifytherequesterwithin10daysofreceiptoftherequestwheretheplansandrecordsmaybeviewedand/orcopied.ConstructionStormwaterGeneralPermit—December1,2010Page21 S6.PERMiTFEESThePermitteemustpaypermitfeesassessedbyEcology.feesforstormwaterdischargescoveredunderthispermitareestablishedbyChapter173-224WAC.EcologycontinuestoassesspermitfeesuntilthepermitisterminatedinaccordancewithSpecialConditionS10orrevokedinaccordancewithGeneralConditionG5.S7.SOLIDANDLIQUIDWASTEDISPOSALThePermitteemusthandleanddisposeofsolidandliquidwastesgeneratedbyconstructionactivity,suchasdemolitiondebris,constructionmaterials,contaminatedmaterials,andwastematerialsfrommaintenanceactivities.includingliquidsandsolidsfromcleaningcatchbasinsandotherstorrnwaterfacilities,inaccordancewith:A.SpecialConditionS3,CompliancewithStandards.B.WAC173-216-110.C.Otherapplicableregulations.S8.DISCHARGESTO303(D)ORTMDLWATERBODIESA.SamplingandNumericEffluentLimitsForCertainDischargesto303(d)-listedWaterBodies1.PermitteeswhodischargetosegmentsofwaterbodieslistedasimpairedbytheStateofWashingtonunderSection303(d)oftheCleanWaterActforturbidity,finesediment,highpH,orphosphorus,mustconductwaterqualitysamplingaccordingtotherequirementsofthissection,andSpecialConditionsS4.C.2.b-fandS4.C.3.b-d,andmustcomplywiththeapplicablenumericeffluentlimitationsinS8.CandS$.D.2.AllreferencesandrequirementsassociatedwithSection303(d)oftheCleanWaterActmeanthemostcurrentlistingbyEcologyofimpairedwaters(Category5)thatexistsonJanuary1,2011,orthedatewhentheoperator’scompletepermitapplicationisreceivedbyEcology,whicheverislater.B.LimitsonCoverazeforNewDischargestoTMDLor303(d)-listedWatersOperatorsofconstructionsitesthatdischargetoa303(d)-listedwaterbodyarenoteligibleforcoverageunderthispermitunlesstheoperator:1.Preventsexposingstormwatertopollutantsforwhichthewaterbodyisimpaired,andretainsdocumentationintheSWPPPthatdetailsprocedurestakentopreventexposureonsite;or2.Documentsthatthepollutantsforwhichthewaterbodyisimpairedarenotpresentatthesite,andretainsdocumentationofthisfindingwithintheSWPPP;orConstructionStormwaterGeneralPermit—December1,2010Page22 -.--3.ProvidesEcologywithdataindicatingthedischargeisnotexpectedtocauseorcontributetoanexceedanceofawaterqualitystandard,andretainssuchdataonsitewiththeSWPPP.TheoperatormustprovidedataandothertechnicalinfonnationtoEcologythatsufficientlydemonstrate:a.fordischargestowaterswithoutanEPA-approvedor-establishedTMDL,thatthedischargeofthepollutantforwhichthewaterisimpairedwillmeetin-streamwaterqualitycriteriaatthepointofdischargetothewaterbody;orb.fordischargestowaterswithanEPA-approvedor-establishedTMDL,thatthereissufficientremainingwasteloadallocationintheTMDLtoallowconstructionstormwaterdischargeandthatexistingdischargerstothewaterbodyaresubjecttocomplianceschedulesdesignedtobringthewaterbodyintoattainmentwithwaterqualitystandards.OperatorsofconstructionsitesareeligibleforcoverageunderthispermitifEcologyissuespermitcoveragebaseduponanaffirmativedeterminationthatthedischargewillnotcauseorcontributetotheexistingimpairment.C.SamplingandNumericEffluentLimitsforDischargestoWaterBodiesonthe303(d)ListforTurbidity,FineSediment,orPhosphorus1.Pennitteeswhodischargetosegmentsofwaterbodiesonthe303(d)list(Category5)forturbidity,finesediment,orphosphorusmustconductturbiditysamplinginaccordancewithSpecialCondition54.C.2andcomplywitheitherofthenumericeffluentlimitsnotedinTable5below.2.Asanalternativetothe25NTUeffluentlimitnotedinTable5below(appliedatthepointwherestormwater[orauthorizednon-stormwater]isdischargedoff-site),pennitteesmaychoosetocomplywiththesurfacewaterqualitystandardforturbidity.Thestandardis:nomorethan5NTUoverbackgroundturbiditywhenthebackgroundturbidityis50NTUorless,ornomorethana10%increaseinturbiditywhenthebackgroundturbidityismorethan50NTU.Inordertousethewaterqualitystandardrequirement,thesamplingmusttakeplaceatthefollowinglocations:a.Backgroundturbidityinthe303(d)-listedreceivingwaterimmediatelyupstream(upgradient)oroutsidetheareaofinfluenceofthedischarge.b.Turbidityatthepointofdischargeintothe303(d)-listedreceivingwater,insidetheareaofinfluenceofthedischarge.3.Dischargesthatexceedthenumericeffluentlimitforturbidityconstituteaviolationofthispermit.4.Penuifteeswhosedischargesexceedthenumericeffluentlimitshallsampledischargesdailyuntiltheviolationiscorrectedandcomplywiththenon-compliancenotificationrequirementsinSpecialConditionS5.F.ConstructionStorrnwaterGeneralPermit—December1,2010Page23 Table5.Turbidity,FineSediment&PhosphorusSamplingandLimitsfor303(d)-ListedWatersD.DischargestoWaterBodiesonthe303(d)ListforHighpHI.Permitteeswhodischargetosegmentsofwaterbodiesonthe303(d)list(Category5)forhighpHmustconductpHsamplinginaccordancewiththetablebelow,andcomplywiththenumericeffluentlimitofpH6.5to8.5su(Table6).Table6.pHSamplingandLimitsfor303(d)-ListedWatersParameteridentifiedinParameterAnalyticalSamplingNumericEffluent303(d)listingSampledlUnitsMethodFrequencyLimitHighpHpH/StandardpHmeterWeekly,ifIntherangeof6.5—Unitsdischarging8.52.AtthePermittee’sdiscretion,compliancewiththelimitshallbeassessedatoneofthefollowinglocations:a.Directlyinthe303(d)-listedwaterbodysegment,insidetheimmediateareaofinfluenceofthedischarge;orb.Alternatively,thepermitteemaymeasurepHatthepointwherethedischargeleavestheconstructionsite,ratherthaninthereceivingwater.3.DischargesthatexceedthenumericeffluentlimitforpH(outsidetherangeof6.5—8.5su)constituteaviolationofthispermit.4.Pennitteeswhosedischargesexceedthenumericeffluentlimitshallsampledischargesdailyuntiltheviolationiscorrectedandcomplywiththenon-compliancenotificationrequirementsinSpecialCondition55.F.ConstructionStol7nwaterGeJ?eralPermit—December1,2010Page24ParameteridentifiedParameterUnitAnalyticalSamplingNumericEffluentin303(d)listingSampledMethodFrequencyLimit1.TurbidityTurbidity-üSM2130orWeekly,if25NTU,atthepoint.FineSedimentEPA18O.1dischargingwherestormwaterisaPhosphorusdischargedfromthesite;ORIncompliancewiththesurfacewaterqualitystandardforturbidity(S8.C.1a)1Permitteessubjecttoanumericeffluentlimitforturbiditymay,attheirdiscretion,chooseeithernumericeffluentlimitationbasedonsite-specificconsiderationsincluding,butnotlimitedto,safety,accessandconvenience. E.SamplingandLimitsforSitesDischargingtoWatersCoveredbyaTMDLorAnotherPollutionControlPlan1.DischargestoawaterbodythatissubjecttoaTotalMaximumDailyLoad(TMDL)forturbidity,finesediment,highpH,orphosphorusmustbeconsistentwiththeTMDL.Refertohttp://www.ecywa.gov/programs/wg/tmdl/index.htmlformoreinfonationonTMDLs.a.WhereanapplicableTMDLsetsspecificwasteloadallocationsorrequirementsfordischargescoveredbythispermit,dischargesmustbeconsistentwithanyspecificwasteloadallocationsorrequirementsestablishedbytheapplicableTMDL.1.ThePermitteemustsampledischargesweeklyorasotherwisespecifiedbytheTMDLtoevaluatecompliancewiththespecificwasteloadallocationsorrequirements.ii.AnalyticalmethodsusedtomeetthemonitoringrequirementsmustconformtothelatestrevisionoftheGuidelinesEstablishingTestProceduresfortheAnalysisofPollutantscontainedin40CFRPart136.TurbidityandpHmethodsneednotbeaccreditedorregisteredunlessconductedatalaboratorywhichmustotherwisebeaccreditedorregistered.b.WhereanapplicableTMDLhasestablishedageneralwasteloadallocationforconstructionstormwaterdischarges,buthasnotidentifiedspecificrequirements,compliancewithSpecialConditions54(Monitoring)and59(SWPPPs)willconstitutecompliancewiththeapprovedTMDL.C.WhereanapplicableTMDLhasnotspecifiedawasteloadallocationforconstructionstorrnwaterdischarges,buthasnotexcludedthesedischarges,compliancewithSpecialConditions54(Monitoring)and59(SWPPPs)willconstitutecompliancewiththeapprovedTMDL.d.WhereanapplicableTMDLspecificallyprecludesorprohibitsdischargesfromconstructionactivity,theoperatorisnoteligibleforcoverageunderthispermit.2.ApplicableTMDLmeansaTMDLforturbidity,finesediment,highpH,orphosphorusthatiscompletedandapprovedbyEPAbeforeJanuary1,2011,orbeforethedatetheoperator’scompletepermitapplicationisreceivedbyEcology,whicheverislater.TMDLscompletedaftertheoperator’scompletepermitapplicationisreceivedbyEcologybecomeapplicabletothePermitteeonlyiftheyareimposedthroughanadministrativeorderbyEcology,orthroughamodificationofpennitcoverage.ConstructionStormwaterGeneralPermitDecember1,2010Page25 S9.STORMWATERPOLLUTiONPREVENTiONPLANThePermittecmustprepareandproperlyimplementanadequateStormwaterPollutionPreventionPlan(SWPPP)forconstructionactivityinaccordancewiththerequirementsofthispermitbeginningwithinitialsoildisturbanceanduntilfinalstabilization.A.ThePermittee’sSWPPPmustmeetthefollowingobjectives:1.Toimplementbestmanagementpractices(BMPs)topreventerosionandsedimentation,andtoidentify,reduce,eliminateorpreventstorrnwatercontaminationandwaterpollutionfromconstructionactivity.2.Topreventviolationsofsurfacewaterquality,groundwaterquality,orsedimentmanagementstandards.3.Tocontrolpeakvolumetricflowratesandvelocitiesofstorrnwaterdischarges.B.GeneralRequirements1.TheSWPPPmustincludeanarrativeanddrawings.AllBMPsmustbeclearlyreferencedinthenarrativeandmarkedonthedrawings.TheSWPPPnarrativemustincludedocumentationtoexplainandjustifythepollutionpreventiondecisionsmadefortheproject.Documentationmustinclude:a.Informationaboutexistingsiteconditions(topography,drainage,soils,vegetation,etc.).b.Potentialerosionproblemareas.C.The12elementsofaSWPPPinSpecialConditionS9.D.l-l2,includingBMPsusedtoaddresseachelement.d.Constructionphasing/sequenceandgeneralBMPimplementationschedule.e.TheactionstobetakenifBMPperformancegoalsarenotachieved—forexample,acontingencyplanforadditionaltreatmentand/orstorageofstormwaterthatwouldviolatethewaterqualitystandardsifdischarged.f.Engineeringcalculationsforpondsandanyotherdesignedstructures.2.ThePermitteemustmodifytheSWPPPif,duringinspectionsorinvestigationsconductedbytheowner/operator,ortheapplicablelocalorstateregulatoryauthority,itisdeterminedthatthe$WPPPis,orwouldbe,ineffectiveineliminatingorsignificantlyminimizingpollutantsinstoimwaterdischargesfromthesite.ThePermitteemustthen:a.Reviewthe$WPPPforcompliancewithSpecialCondition59andmakeappropriaterevisionswithin7daysoftheinspectionorinvestigation.b.Immediatelybegintheprocesstofullyimplementandmaintainappropriatesourcecontroland/ortreatmentBMPsassoonaspossible,addressingtheproblemsnolaterthan10daysfromtheinspectionorinvestigation.IfConstructionStol7nwaterGeneralPermit—December1,2010Page26 installationofnecessarytreatmentBMPsisnotfeasiblewithin10days,EcologymayapproveadditionaltimewhenanextensionisrequestedbyaPermittcewithintheinitialI0-dayresponseperiod,C.DocumentBMPimplementationandmaintenanceinthesitelogbook.ThePermitteemustmodifytheSWPPPwheneverthereisachangeindesign,construction,operation,ormaintenanceattheconstructionsitethathas,orcouldhave,asignificanteffectonthedischargeofpollutantstowatersoftheState.C.StorrnwaterBestManagementPracticestBMPs)BMPsmustbeconsistentwith:1.StormwaterManagementManualforWesternWashington(mostrecentedition),forsiteswestofthecrestoftileCascadeMountains;or2.StorrnwaterManagementManualforEasternWashington(mostrecentedition),forsiteseastofthecrestoftheCascadeMountains;or3.RevisionstothemanualslistedinSpecialConditionS9.C.l.&2.,orotherstormwatermanagementguidancedocumentsormanualswhichprovideanequivalentlevelofpollutionprevention,thatareapprovedbyEcologyandincorporatedintothispermitinaccordancewiththepermitmodificationrequirementsofWAC173-226-230;or4.DocumentationintheSWPPPthattheBMPsselectedprovideanequivalentlevelofpollutionprevention,comparedtotheapplicableStorrnwaterManagementManuals,including:a.ThetechnicalbasisfortheselectionofallstormwaterBMPs(scientific,technicalstudies,and/ormodeling)thatsupporttheperformanceclaimsfortheBMPsbeingselected.b.AnassessmentofhowtheselectedBMPwillsatisfyAKARTrequirementsandtheapplicablefederaltechnology-basedtreatmentrequirementsunder40CfRpart125.3.D.SWPPP—NarrativeContentsandRequirementsThePermitteemustincludeeachofthe12elementsbelowinSpecialConditionS9.D.1-12inthenarrativeoftheSWPPPandimplementthemunlesssiteconditionsrendertheelementunnecessaryandtheexemptionfromthatelementisclearlyjustifiedintheSWPPP.1.PreserveVegetation/MarkClearingLimitsa.Beforebeginningland-disturbingactivities,includingclearingandgrading,clearlymarkallclearinglimits,sensitiveareasandtheirbuffers,andtreesthataretobepreservedwithintheconstructionarea.ConstructionStorrnwaterGeneralPermit—December1,2010Page27 b.Retainthedufflayer.nativetopsoil,andnaturalvegetationinanundisturbedstatetothemaximumdegreepracticable.2.EstablishConstructionAccessa.Limitconstructionvehicleaccessandexittooneroute,ifPossible.b.Stabilizeaccesspointswithapadofquarryspalls,crushedrock,orotherequivalentBMPs.tominimizetrackingsedimentontoroads.C.Locatewheelwashortirebathsonsite,ifthestabilizedconstructionentranceisnoteffectiveinpreventingtrackingsedimentontoroads.d.Ifsedimentistrackedoffsite,cleantheaffectedroadwaythoroughlyattheendofeachday,ormorefrequentlyasnecessary(forexample,duringwetweather).Removesedimentfromroadsbyshoveling,sweeping,orpickupandtransportofthesedimenttoacontrolledsedimentdisposalarea.C.ConductstreetwashingonlyaftersedimentremovalinaccordancewithSpecialConditionS9.D.2.d.ControlstreetwashwastewaterbypumpingbackonsiteorotherwisepreventingitfromdischargingintosystemstributarytowatersoftheState.3.ControlFlowRatesa.Protectpropertiesandwaterwaysdownstreamofdevelopmentsitesfromerosionandtheassociateddischargeofturbidwatersduetoincreasesinthevelocityandpeakvolumetricflowrateofstormwaterrunofffromtheprojectsite,asrequiredbylocalplanapprovalauthority.b.WherenecessarytocomplywithSpecialConditionS9.D.3.a,constructstormwaterretentionordetentionfacilitiesasoneofthefirststepsingrading.Assurethatdetentionfacilitiesfunctionproperlybeforeconstructingsiteimprovements(forexample,impervioussurfaces).C.Ifperrnanentinfiltrationpondsareusedforflowcontrolduringconstruction,protectthesefacilitiesfromsiltationduringtheconstructionphase.4.InstallSedimentControlsThePermitteemustdesign,installandmaintaineffectiveerosioncontrolsandsedimentcontrolstominimizethedischargeofpollutants.Ataminimum,thePermitteemustdesign,installandmaintainsuchcontrolsto:a.ConstructsedimentcontrolBMPs(sedimentponds,traps,filters,etc.)asoneofthefirststepsingrading.TheseBMPsmustbefunctionalbeforeotherlanddisturbingactivitiestakeplace.b.Minimizesedimentdischargesfromthesite.Thedesign,installationandmaintenanceoferosionandsedimentcontrolsmustaddressfactorssuchastheamount,frequency,intensityanddurationofprecipitation,thenatureofConstructionStorrnwaterGeneralPern’iit—December1,2010Page28 resultingstomwatcrrunoffandsoilcharacteristics,includingtherangeofsoilparticlesizesexpectedtobepresentonthesite.C.DirectstonmvatcrrunofffromdisturbedareasthroughasedimentpondorotherappropriatesedimentremovalBMP,beforetherunoffleavesaconstructionsiteorbeforedischargetoaninfiltrationfacility.RunofffromfullystabilizedareasmaybedischargedwithoutasedimentremovalBMP,butmustmeettheflowcontrolperformancestandardofSpecialConditionS9.D.3.a.d.LocateBMPsintendedtotrapsedimentonsiteinamannertoavoidinterferencewiththemovementofjuvenilesalmonidsattemptingtoenteroff-channelareasordrainages.e.Provideandmaintainnaturalbuffersaroundsurfacewaters,directstorrnwatertovegetatedareastoincreasesedimentremovalandmaximizestormwaterinfiltration,unlessinfeasible.f.Wherefeasible,designoutletstructuresthatwithdrawimpoundedstormwaterfromthesurfacetoavoiddischargingsedimentthatisstillsuspendedlowerinthewatercolumn.5.StabilizeSoilsa.ThePermitteemuststabilizeexposedandunworkedsoilsbyapplicationofeffectiveBMPsthatpreventerosion.ApplicableBMPsinclude,butarenotlimitedto:temporaryandpermanentseeding,sodding,mulching,plasticcovering,erosioncontrolfabricsandmatting,soilapplicationofpolyacrylarnide(PAM),theearlyapplicationofgravelbaseonareastobepaved,anddustcontrol.b.ThePermitteemustcontrolstormwatervolumeandvelocitywithinthesitetominimizesoilerosion.C.ThePermitteemustcontrolstormwaterdischarges,includingbothpeakflowratesandtotalstorrnwatervolume,tominimizeerosionatoutletsandtominimizedownstreamchannelandstreambankerosion.d.Dependingonthegeographiclocationoftheproject,thePermitteemustnotallowsoilstoremainexposedandunworkedformorethanthetimeperiodssetforthbelowtopreventerosion:WestoftheCascadeMountainsCrestDuringthedryseason(May1-Sept.30):7daysDuringthewetseason(October1-April30):2daysEastoftheCascadeMountainsCrest,exceptforCentralBasin*Duringthedryseason(July1-September30):10daysDuringthewetseason(October1-June30):5daysTheCentralBasin*,EastoftheCascadeMountainsCrestConstructionStormwaterGeneralPermit—December1,2010Page29 DuringthedrySeason(July1-September30):30daysDuringthewetseason(October1-June30):15days*Note.TheCentralBasinisdefinedastheportionsofEasternWashingtonwithmeanannualprecipitationoflessthan12inches.e.ThePermitteemuststabilizesoilsattheendoftheshiftbeforeaholidayorweekendifneededbasedontheweatherforecast.f.ThePenriitteemuststabilizesoilstockpilesfromerosion,protectedwithsedimenttrappingmeasures,andwherepossible,belocatedawayfromstormdraininlets,waterways,anddrainagechannels.g.ThePermitteemustminimizetheamountofsoilexposedduringconstructionactivity.h.ThePermitteemustminimizethedisturbanceofsteepslopes.ThePermitteemustminimizesoilcompactionand,unlessinfeasible,preservetopsoil.6.ProtectSlopesa.ThePermitteemustdesignandconstructcut-and-fillslopesinamannertominimizeerosion.Applicablepracticesinclude,butarenotlimitedto,reducingcontinuouslengthofslopewithterracinganddiversions,reducingslopesteepness,androugheningslopesurfaces(forexample,trackwalking).b.ThePermitteemustdivertoff-sitestorrnwater(run-on)orgroundwaterawayfromslopesanddisturbedareaswithinterceptordikes,pipes,and/orswales.Off-sitestormwatershouldbemanagedseparatelyfromstonnwatergeneratedonthesite.C.Atthetopofslopes,collectdrainageinpipeslopedrainsorprotectedchannelstopreventerosion.i.WestoftheCascadeMountainsCrest:Temporarypipeslopedrainsmusthandlethepeak10-minutevelocityofflowfromaType1A,10-year,24-hourfrequencystormforthedevelopedcondition.Alternatively,the10-year,1-hourflowratepredictedbyanapprovedcontinuousrunoffmodel,increasedbyafactorof1.6,maybeused.Thehydrologicanalysismustusetheexistinglandcoverconditionforpredictingflowratesfromtributaryareasoutsidetheprojectlimits.Fortributaryareasontheprojectsite,theanalysismustusethetemporaryorpermanentprojectlandcovercondition,whicheverwillproducethehighestflowrates.IfusingtheWesternWashingtonHydrologyModel(WWHM)topredictflows,baresoilareasshouldbemodeledas“landscapedarea.”ConstructionStol7nwaterGeneralPermit—December1,2010Page30 ii.EastoftheCascadeMountainsCrest:Temporarypipeslopedrainsmusthandletheexpectedpeakflowvelocityfroma6-month,3-hourstormforthedevelopedcondition.referredtoastheshortdurationstorm.d.Placeexcavatedmaterialontheuphillsideoftrenches,consistentwithsafetyandspaceconsiderations.e.Placecheckdarnsatregularintervalswithinconstructedchannelsthatarecutdownaslope.7.ProtectDrainInletsa.Protectallstormdraininletsmadeoperableduringconstructionsothatstorrnwaterrunoffdoesnotentertheconveyancesystemwithoutfirstbeingfilteredortreatedtoremovesediment.b.Cleanorremoveandreplaceinletprotectiondeviceswhensedimenthasfilledone-thirdoftheavailablestorage(unlessadifferentstandardisspecifiedbytheproductmanufacturer).8.StabilizeChannelsandOutletsa.Design,constructandstabilizeallon-siteconveyancechannelstopreventerosionfromthefollowingexpectedpeakflows:i.WestoftheCascadeMountainsCrest:Channelsmusthandlethepeak10-minutevelocityofflowfromaTypelA,10-year,24-hourfrequencystormforthedevelopedcondition.Alternatively,the10-year,i-hourflowrateindicatedbyanapprovedcontinuousrunoffmodel,increasedbyafactorof1.6,maybeused.Thehydrologicanalysismustusetheexistinglandcoverconditionforpredictingflowratesfromtributaryareasoutsidetheprojectlimits.Fortributaryareasontheprojectsite,theanalysismustusethetemporaryorpermanentprojectlandcovercondition,whicheverwillproducethehighestflowrates.IfusingtheWWFIMtopredictflows,baresoilareasshouldbemodeledas“landscapedarea.”ii.EastoftheCascadeMountainsCrest:Channelsmusthandletheexpectedpeakflowvelocityfroma6-month,3-hourstormforthedevelopedcondition,referredtoastheshortdurationstorm.b.Providestabilization,includingarmoringmaterial,adequatetopreventerosionofoutlets,adjacentstreambanks,slopes,anddownstreamreachesattheoutletsofallconveyancesystems.9.ControlPollutantsDesign,install,implementandmaintaineffectivepollutionpreventionmeasurestominimizethedischargeofpollutants.ThePermitteemust:ConstructionStol7nwaterGeneralPennit—December1,2010Page31 a.Handleanddisposeofallpollutants.includingwastematerialsanddemolitiondebristhatoccuronsiteinamannerthatdoesnotcausecontaminationofstonrnvater.b.Providecover,containment,andprotectionfromvandalismforallchemicals.liquidproducts,petroleumproducts,andothermaterialsthathavethepotentialtoposeathreattohumanhealthortheenvironment.On-sitefuelingtanksmustincludesecondarycontainment.Secondarycontainmentmeansplacingtanksorcontainerswithinanimperviousstructurecapableofcontaining110%ofthevolumecontainedinthelargesttankwithinthecontainmentstructure.Double-walledtanksdonotrequireadditionalsecondarycontainment.C.Conductmaintenance,fueling,andrepairofheavyequipmentandvehiclesusingspillpreventionandcontrolmeasures.Cleancontaminatedsurfacesimmediatelyfollowinganyspillincident.d.Dischargewheelwashortirebathwastewatertoaseparateon-sitetreatmentsystemthatpreventsdischargetosurfacewater,suchasclosed-looprecirculationoruplandlandapplication,ortothesanitarysewerwithlocalsewerdistrictapproval.e.ApplyfertilizersandpesticidesinamaimerandatapplicationratesthatwillnotresultinlossofchemicaltostormwaterrunoffFollowmanufacturers’labelrequirementsforapplicationratesandprocedures.f.UseBMPstopreventcontaminationofstormwaterrunoffbypH-modifyingsources.Thesourcesforthiscontaminationinclude,butarenotlimitedto:bulkcement,cementkilndust,flyash,newconcretewashingandcuringwaters,wastestreamsgeneratedfromconcretegrindingandsawing,exposedaggregateprocesses,dewateringconcretevaults,concretepumpingandmixerwashoutwaters.(Alsorefertothedefinitionfor“concretewastewater”inAppendixA--Defmitions.)g.AdjustthepHofstormwaterifnecessarytopreventviolationsofwaterqualitystandards.h.Assurethatwashoutofconcretetrucksisperformedoffsiteorindesignatedconcretewashoutareasonly.Donotwashoutconcretetrucksontotheground,ofintostormdrains,openditches,streets,orstreams.Donotdumpexcessconcreteonsite,exceptindesignatedconcretewashoutareas.ConcretespillageorconcretedischargetosurfacewatersoftheStateisprohibited.i.ObtainwrittenapprovalfromEcologybeforeusingchemicaltreatmentotherthanCO2ordryicetoadjustpH.10.ControlDewateñnga.Permifteesmustdischargefoundation,vault,andtrenchdewateñngwater,whichhavecharacteristicssimilartostormwaterrunoffatthesite,intoaConstntctiol?StonnwaterGeneralPermit—December1,2010Page32 controlledconveyancesystembeforedischargetoasedimenttraporsedimentpond.b.Penitteesmaydischargeclean,non-turbiddewateringwater.suchaswell-pointgroundwater,tosystemstributaryto,ordirectlyintosurfacewatersoftheState.asspecifiedinSpecialConditionS9.D.8,providedthedewateringflowdoesnotcauseerosionorfloodingofreceivingwaters.Donotroutecleandewateringwaterthroughstorrnwatersedimentponds.Notethat“surfacewatersoftheState”mayexistonaconstructionsiteaswellasoffsite;forexample,acreekrunningthroughasite.C.Othertreatmentordisposaloptionsmayinclude:i.Infiltration.ii.Transportoffsiteinavehicle,suchasavacuumflushtruck,forlegaldisposalinamannerthatdoesnotpollutestatewaters.iii.Ecology-approvedon-sitechemicaltreatmentorothersuitabletreatmenttechnologies.iv.Sanitaryorcombinedsewerdischargewithlocalsewerdistrictapproval,ifthereisnootheroption.V.Useofasedimentationbagwithdischargetoaditchorswaleforsmallvolumesoflocalizeddewatering.d.Permifteesmusthandlehighlyturbidorcontaminateddewateringwaterseparatelyfromstormwater.11.MaintainBMPsa.PermifteesmustmaintainandrepairalltemporaryandpermanenterosionandsedimentcontrolBMPsasneededtoassurecontinuedperformanceoftheirintendedfunctioninaccordancewithBMPspecifications.b.PermitteesmustremovealltemporaryerosionandsedimentcontrolBMPswithin30daysafterachievingfinalsitestabilizationorafterthetemporaryBMPsarenolongerneeded.12.ManagetheProjecta.Phasedevelopmentprojectstothemaximumdegreepracticableandtakeintoaccountseasonalworklimitations.b.Inspectionandmonitoring--Inspect,maintainandrepairallBMPsasneededtoassurecontinuedperformanceoftheirintendedfunction.ConductsiteinspectionsandmonitoringinaccordancewithSpecialConditionS4.C.MaintaininganupdatedconstructionSWPPP--Maintain,update,andimplementtheSWPPPinaccordancewithSpecialConditionsS3,S4and$9.Constructiol?StorinwaterGeneralPermit—December1,2010Page33 E.SWPPP—MapContentsandRequirementsThePermitte&sSWPPPmustalsoincludeavicinitymaporgenerallocationmap(forexample,aUSGSquadranglemap,aportionofacountyorcitymap,orotherappropriatemap)withenoughdetailtoidentifythelocationoftheconstructionsiteandreceivingwaterswithinonemileofthesite.TheSWPPPmustalsoincludealegiblesitemap(ormaps)showingtheentireconstructionsite.Thefollowingfeaturesmustbeidentified.unlessnotapplicableduetositeconditions:1.Thedirectionofnorth,propertylines,andexistingstructuresandroads.2.Cutandfillslopesindicatingthetopandbottomofslopecatchlines.3.Approximateslopes,contours,anddirectionofstormwaterflowbeforeandaftermajorgradingactivities.4.Areasofsoildisturbanceandareasthatwillnotbedisturbed.5.Locationsofstructuralandnonstructuralcontrols(BMPs)identifiedintheswPPP.6.Locationsofoff-sitematerial,stockpiles,wastestorage,borrowareas,andvehicle/equipmentstorageareas.7.Locationsofallsurfacewaterbodies,includingwetlands.8.Locationswherestormwaterornon-storrnwaterdischargesoff-siteand/ortoasurfacewaterbody,includingwetlands.9.Locationofwaterqualitysamplingstation(s),ifsamplingisrequiredbystateorlocalpermittingauthority.10.Areaswherefinalstabilizationhasbeenaccomplishedandnofurtherconstruction-phasepermitrequirementsapply.$10.NOTICEOfTERMINATIONA.Thesiteiseligibleforterminationofcoveragewhenithasmetanyofthefollowingconditions:1.Thesitehasundergonefinalstabilization,thePeimitteehasremovedalltemporaryBMPs(exceptbiodegradableBMPsclearlymanufacturedwiththeintentionforthematerialtobeleftinplaceandnotinterferewithmaintenanceorlanduse),andallstormwaterdischargesassociatedwithconstructionactivityhavebeeneliminated;or2.AllportionsofthesitethathavenotundergonefinalstabilizationperSpecialConditionS1O.A.1havebeensoldand/ortransferred(perGeneralConditionG9),andthePermitteenolongerhasoperationalcontroloftheconstructionactivity;orConstructionStOl7flWaterGeneralPermit—December1,2010Page34 3.Forresidentialconstructiononly.thePennitteehascompletedtemporarystabilizationandthehomeownershavetakenpossessionoftheresidences.B.Whenthesiteiseligiblefortermination,thePermitteemustsubmitacompleteandaccurateNoticeofTermination(NOT)form,signedinaccordancewithGeneralConditionG2,to:DepartmentofEcologyWaterQualityProgram-ConstructionStormwaterPOBox47696Olympia,Washington98504-7696TheterminationiseffectiveonthedateEcologyreceivestheNOTform,unlessEcologynotifiesthePermitteewithin30daysthatterminationrequestisdeniedbecausethePermitteehasnotmettheeligibilityrequirementsinSpecialConditionSl0.A..Permitteestransferringthepropertytoanewpropertyowneroroperator/permitteearerequiredtocompleteandsubmittheNoticeofTransferformtoEcology,butarenotrequiredtosubmitaNoticeofTerminationformforthistypeoftransaction.ConstructionStormwaterGeneralPer,iiit—December1,2010Page35 GENERALCONDITiONSGi.DISCHARGEVIOLATIONSAlldischargesandactivitiesauthorizedbythisgeneralpermitmustbeconsistentwiththetermsandconditionsofthisgeneralpermit.Anydischargeofanypollutantmorefrequentthanoratalevelinexcessofthatidentifiedandauthorizedbythegeneralpermitmustconstituteaviolationofthetermsandconditionsofthispermit.G2.SIGNATORYREQUIREMENTSA.Allpermitapplicationsmustbearacertificationofcorrectnesstobesigned:1.Inthecaseofcorporations,byaresponsiblecorporateofficerofatleastthelevelofvicepresidentofacorporation;2.Inthecaseofapartnership,byageneralpartnerofapartnership;3.Inthecaseofsoleproprietorship,bytheproprietor;or4.Inthecaseofamunicipal,state,orotherpublicfacility,byeitheraprincipalexecutiveofficerorrankingelectedofficial.B.AllreportsrequiredbythispermitandotherinformationrequestedbyEcologymustbesignedbyapersondescribedaboveorbyadulyauthorizedrepresentativeofthatperson.Apersonisadulyauthorizedrepresentativeonlyif:1.TheauthorizationismadeinwritingbyapersondescribedaboveandsubmittedtotheEcology.2.Theauthorizationspecifieseitheranindividualorapositionhavingresponsibilityfortheoveralloperationoftheregulatedfacility,suchasthepositionofplantmanager,superintendent,positionofequivalentresponsibility,oranindividualorpositionhavingoverallresponsibilityforenvironmentalmatters.C.Changestoauthorization.IfanauthorizationunderparagraphG2.B.2aboveisnolongeraccuratebecauseadifferentindividualorpositionhasresponsibilityfortheoveralloperationofthefacility,anewauthorizationsatisfyingtherequirementsofparagraphG2.B.2abovemustbesubmittedtoEcologypriortoortogetherwithanyreports,information,orapplicationstobesignedbyanauthorizedrepresentative.D.Certification.Anypersonsigningadocumentunderthissectionmustmakethefollowingcertification:“Icertifyunderpenaltyoflaw,thatthisdocumentandallattachmentswerepreparedundermydirectionorsupervisioninaccordancewithasystemdesignedtoassurethatqualifiedpersonnelproperlygatheredandevaluatedtheinformationsubmitted.Basedonmyinquiryofthepersonorpersonswhomanagethesystem,orthosepersonsdirectlyresponsibleforgatheringConstructionStol7nwaterGeneralPermit—December1,2010Page36 information,theinformationsubmittedis.tothebestofrnyknowledgeandbelief,true,accurate,andcomplete.Iamawarethattherearesignificantpenaltiesforsubmittingfalseinformation,includingthepossibilityoffineandimprisonmentforknowingviolations”G3.RIGHTOFINSPECTIONANDENTRYThePermitteemtistallowanauthorizedrepresentativeofEcology,uponthepresentationofcredentialsandsuchotherdocumentsasmayberequiredbylaw:A.Toenteruponthepremiseswhereadischargeislocatedorwhereanyrecordsarekeptunderthetermsandconditionsofthispermit.B.Tohaveaccesstoandcopy—atreasonabletimesandatreasonablecost--anyrecordsrequiredtobekeptunderthetermsandconditionsofthispermit.C.Toinspect--atreasonabletimes—anyfacilities,equipment(includingmonitoringandcontrolequipment),practices,methods,oroperationsregulatedorrequiredunderthispermit.D.Tosampleormonitor—atreasonabletimes—anysubstancesorparametersatanylocationforpurposesofassuringpermitcomplianceorasotherwiseauthorizedbytheCleanWaterAct.G4.GENERALPERMITMODIFICATIONANDREVOCATIONThispermitmaybemodified,revokedandreissued,orterminatedinaccordancewiththeprovisionsofChapter173-226WAC.Groundsformodification,revocationandreissuance,orterminationinclude,butarenotlimitedto,thefollowing:A.Whenachangeoccursinthetechnologyorpracticesforcontrolorabatementofpollutantsapplicabletothecategoryofdischargerscoveredunderthispermit.B.WheneffluentlimitationguidelinesorstandardsarepromulgatedpursuanttotheCWAorChapter90.48RCW,forthecategoryofdischargerscoveredunderthispermit.C.Whenawaterqualitymanagementplancontainingrequirementsapplicabletothecategoryofdischargerscoveredunderthispermitisapproved,orD.Wheninformationisobtainedthatindicatescumulativeeffectsontheenvironmentfromdischargerscoveredunderthispermitareunacceptable.G5.REVOCATIONOFCOVERAGEUNDERTHEPERMITPursuanttoChapter43.21BRCWandChapter173-226WAC,theDirectormayterminatecoverageforanydischargerunderthispermitforcause.Caseswherecoveragemaybeterminatedinclude,butarenotlimitedto,thefollowing:ConstructionStormwaterGeneralPermit—December1,2010Page37 A.Vio’ationofanytermorconditionofthispemit.B.Obtainingcoverageunderthispermitbymisrepresentationorfailuretodisclosefullyallrelevantfacts.C.Achangeinanyconditionthatrequireseitheratemporaryorpermanentreductionoreliminationofthepenriitteddischarge.D.failureorrefusalofthePermitteetoallowentryasrequiredinRCW90.48.090.E.Adetenuinationthatthepermittedactivityendangershumanhealthortheenvironment,orcontributestowaterqualitystandardsviolations.F.NonpaymentofpermitfeesorpenaltiesassessedpursuanttoRCW90.48.465andChapter173-224WAC.G.FailureofthePermitteetosatisfythepublicnoticerequirementsofWAC173-226-130(5),whenapplicable.TheDirectormayrequireanydischargerunderthispermittoapplyforandobtaincoverageunderanindividualpermitoranothermorespecificgeneralpermit.PermitteeswhohavetheircoveragerevokedforcauseaccordingtoWAC173-226-240mayrequesttemporarycoverageunderthispermitduringthetimeanindividualpermitisbeingdeveloped,providedtherequestismadewithinninety(90)daysfromthetimeofrevocationandissubmittedalongwithacompleteindividualpermitapplicationform.G6.REPORTINGACAUSEFORMODIFICATIONThePermifteemustsubmitanewapplication,orasupplementtothepreviousapplication,wheneveramaterialchangetotheconstructionactivityorinthequantityortypeofdischargeisanticipatedwhichisnotspecificallyauthorizedbythispermit.Thisapplicationmustbesubmittedatleastsixty(60)dayspriortoanyproposedchanges.filingarequestforapermitmodification,revocationandreissuance,ortermination,oranotificationofplannedchangesoranticipatednoncompliancedoesnotrelievethePermitteeofthedutytocomplywiththeexistingpermituntilitismodifiedorreissued.G7.COMPLIANCEWITHOTHERLAWSANDSTATUTESNothinginthispermitwillbeconstruedasexcusingthePennitteefromcompliancewithanyapplicablefederal,state,orlocalstatutes,ordinances,orregulations.G$.DUTYTOREAPPLYThePermitteemustapplyforpermitrenewalatleast180dayspriortothespecifiedexpirationdateofthispermit.ConstructionStol7nwaterGeneralPermit—December1,2010Page38 G9.TRANSFEROFGENERALPER1’1ITCOVERAGECoverageunderthisgeneralpenitisautomaticallytransferredtoanewdischarger.includingoperatorsoflots/parcelswithinacommonplanofdevelopmentorsale,if:A.Awrittenagreement(TransferofCoverageform)betweenthecurrentdischarger(Pemittee)andnewdischarger,signedbybothpartiesandcontainingaspecificdatefortransferofpermitresponsibility,coverage,andliabilityissubmittedtotheDirector;andB.TheDirectordoesnotnotifythecurrentdischargerandnewdischargeroftheDirector’sintenttorevokecoverageunderthegeneralpermit.Ifthisnoticeisnotgiven,thetransferiseffectiveonthedatespecifiedinthewrittenagreement.Whenacurrentdischarger(Pennittee)transfersaportionofapermittedsite,thecurrentdischargermustalsosubmitanupdatedapplicationform(NOl)totheDirectorindicatingtheremainingpermittedacreageafterthetransfer.Gb.REMOVEDSUBSTANCESThePermitteemustnotre-suspendorreintroducecollectedscreenings,grit,solids,sludges,filterbackwash,orotherpollutantsremovedinthecourseoftreatmentorcontrolofstorrnwatertothefinaleffluentstreamfordischargetostatewaters.Gil.DUTYTOPROVIDEINFORMATIONThePermitteemustsubmittoEcology,withinareasonabletime,allinformationthatEcologymayrequesttodeterminewhethercauseexistsformodifying,revokingandreissuing,orterminatingthispermitortodeterminecompliancewiththispermit.ThePermitteemustalsosubmittoEcology,uponrequest,copiesofrecordsrequiredtobekeptbythispermit[40CFR122.41(h)].Gi2.OTHERREQUIREMENTSOF40CFRAllotherrequirementsof4OCFR122.41and122.42areincorporatedinthispennitbyreference.Gl3.ADDITIONALMONITORINGEcologymayestablishspecificmonitoringrequirementsinadditiontothosecontainedinthispermitbyadministrativeorderorpermitmodification.ConstructionStol7nwaterGeneralPermit—December1,2010Page39 G14.PENALTiESFORVIOLATINGPERMITCONDiTIONSAnypersonwhoisfoundguiltyofwillfullyviolatingthetermsandconditionsofthispermitshallbedeemedguiltyofacrime,anduponconvictionthereofshallbepunishedbyafineofuptotenthousanddollars($10,000)andcostsofprosecution,orbyimprisonmentinthediscretionofthecourt.Eachdayuponwhichawillfulviolationoccursmaybedeemedaseparateandadditionalviolation.Anyersonwhoviolatesthetermsandconditionsofawastedischargepermitshallincur.inadditiontoanyotherpenaltyasprovidedbylaw,acivilpenaltyintheamountofuptotenthousanddollars($lOOOO)foreverysuchviolation.Eachandeverysuchviolationshallbeaseparateanddistinctoffense,andincaseofacontinuingviolation,everyday’scontinuanceshallbedeemedtobeaseparateanddistinctviolation.G15.UPSETDefinition—“Upset”meansanexceptionalincidentinwhichthereisunintentionalandtemporarynoncompliancewithtechnology-basedpermiteffluentlimitationsbecauseoffactorsbeyondthereasonablecontrolofthePermittee.Anupsetdoesnotincludenoncompliancetotheextentcausedbyoperationalerror,improperlydesignedtreatmentfacilities,inadequatetreatmentfacilities,lackofpreventivemaintenance,orcarelessorimproperoperation.Anupsetconstitutesanaffirmativedefensetoanactionbroughtfornoncompliancewithsuchtechnology-basedpermiteffluentlimitationsiftherequirementsofthefollowingparagrapharemet.APermitteewhowishestoestablishtheaffirmativedefenseofupsetmustdemonstrate,throughproperlysigned,contemporaneousoperatinglogsorotherrelevantevidencethat:1)anupsetoccurredandthatthePermitteecanidentifythecause(s)oftheupset;2)thepermittedfacilitywasbeingproperlyoperatedatthetimeoftheupset;3)thePermitteesubmittednoticeoftheupsetasrequiredinSpecialCondition55.f,and;4)thePermitteecompliedwithanyremedialmeasuresrequiredunderthispermit.Inanyenforcementproceeding,thePermitteeseekingtoestablishtheoccurrenceofanupsethastheburdenofproof.G16.PROPERTYRIGHTSThispermitdoesnotconveyanypropertyrightsofanysort,oranyexclusiveprivilege.G17.DUTYTOCOMPLYThePermitteemustcomplywithallconditionsofthispermit.AnypermitnoncomplianceconstitutesaviolationoftheCleanWaterActandisgroundsforenforcementaction;forpennittermination,revocationandreissuance,ormodification;ordenialofapermitrenewalapplication.ConstructionStormwaterGeneralPermit—December1,2010Page40 cis.TOXICPOLLUTANTSThePermitteemustcomplywitheffluentstandardsorprohibitionsestablishedunderSection307(a)oftheCleanWaterActfortoxicpollutantswithinthetimeprovidedintheregulationsthatestablishthosestandardsorprohibitions,evenifthispenithasnotyetbeenmodifiedtoincorporatetherequirement.G19.PENALTIESFORTAMPERINGTheCleanWaterActprovidesthatanypersonwhofalsifies,tamperswith,orknowinglyrendersinaccurateanymonitoringdeviceormethodrequiredtobemaintainedunderthispermitshall,uponconviction,bepunishedbyafineofnotmorethan$10,000perviolation,orbyimprisonmentfornotmorethantwoyearsperviolation,orbyboth.Ifaconvictionofapersonisforaviolationcommittedafterafirstconvictionofsuchpersonunderthiscondition,punishmentshallbeafineofnotmorethan$20,000perdayofviolation,orimprisonmentofnotmorethanfour(4)years,orboth.G20.REPORTINGPLANNEDCHANGESThePermitteemust,assoonaspossible,givenoticetoEcologyofplannedphysicalalterations,modificationsoradditionstothepermittedconstructionactivity.ThePermitteeshouldbeawarethat,dependingonthenatureandsizeofthechangestotheoriginalpermit,anewpublicnoticeandotherpermitprocessrequirementsmayberequired.ChangesinactivitiesthatrequirereportingtoEcologyincludethosethatwillresultin:A.Thepermittedfacilitybeingdeterminedtobeanewsourcepursuantto40CfR122.29(b).B.Asignificantchangeinthenatureoranincreaseinquantityofpollutantsdischarged,includingbutnotlimitedto:forsites5acresorlarger,a20%orgreaterincreaseinacreagedisturbedbyconstructionactivity.C.Achangeinoradditionofsurfacewater(s)receivingstormwaterornon-stonnwaterfromtheconstructionactivity.D.Achangeintheconstructionplansand/oractivitythataffectsthePermittee’smonitoringrequirementsinSpecialConditionS4.followingsuchnotice,permitcoveragemaybemodified,orrevokedandreissuedpursuantto40CfR122.62(a)tospecifyandlimitanypollutantsnotpreviouslylimited.Untilsuchmodificationiseffective,anyneworincreaseddischargeinexcessofpermitlimitsornotspecificallyauthorizedbythispermitconstitutesaviolation.ConstructionStormwaterGeneralPermit—December1,20]0Page4l C21.REPORTiNGOTHERINFORMATiONWherethePermitteebecomesawarethatitfailedtosubmitanyrelevantfactsinapermitapplication,orsubmittedincorrectinformationinapermitapplicationorinanyreporttoEcology,itmustpromptlysubmitsuchfactsorinformation.G22.REPORTINGANTICIPATEDNON-COMPLIANCEThePermitteemustgiveadvancenoticetoEcologybysubmissionofanewapplicationorsupplementtheretoatleastforty-five(45)dayspriortocommencementofsuchdischarges,ofanyfacilityexpansions,productionincreases,orotherplannedchanges,suchasprocessmodifications,inthepermittedfacilityoractivitywhichmayresultinnoncompliancewithpermitlimitsorconditions.Anymaintenanceoffacilities,whichmightnecessitateunavoidableinterruptionofoperationanddegradationofeffluentquality,mustbescheduledduringnon-criticalwaterqualityperiodsandcarriedoutinamannerapprovedbyEcology.G23.REQUESTSTOBEEXCLUDEDFROMCOVERAGEUNDERTHEPERMITAnydischargerauthorizedbythispermitmayrequesttobeexcludedfromcoverageunderthegeneralpermitbyapplyingforanindividualpermit.ThedischargermustsubmittotheDirectoranapplicationasdescribedinWAC173-220-040orWAC173-216-070,whicheverisapplicable,withreasonssupportingtherequest.Thesereasonswillfullydocumenthowanindividualpermitwillapplytotheapplicantinawaythatthegeneralpermitcannot.Ecologymaymakespecificrequestsforinformationtosupporttherequest.TheDirectorwilleitherissueanindividualpermitordenytherequestwithastatementexplainingthereasonforthedenial.Whenanindividualpermitisissuedtoadischargerotherwisesubjecttotheconstructionstormwatergeneralpermit,theapplicabilityoftheconstructionstorrnwatergeneralpermittothatPermitteeisautomaticallyterminatedontheeffectivedateoftheindividualpermit.G24.APPEALSA.Thetermsandconditionsofthisgeneralpermit,astheyapplytotheappropriateclassofdischargers,aresubjecttoappealbyanypersonwithin30daysofissuanceofthisgeneralpermit,inaccordancewithChapter43.21BRCW,andChapter173-226WAC.B.Thetermsandconditionsofthisgeneralpermit,astheyapplytoanindividualdischarger,areappealableinaccordancewithChapter43.21BRCWwithin30daysoftheeffectivedateofcoverageofthatdischarger.Considerationofanappealofgeneralpermitcoverageofanindividualdischargerislimitedtothegeneralpermit’sapplicabilityornonapplicabilitytothatindividualdischarger.C.Theappealofgeneralpermitcoverageofanindividualdischargerdoesnotaffectanyotherdischargerscoveredunderthisgeneralpermit.Ifthetermsandconditionsofthisgeneralpermitarefoundtobeinapplicabletoanyindividualdischarger(s),thematterConstructionStol7nwaterGeneralPermit—December1,2010Page42 shallberemandedtoEcologyforconsiderationofissuanceofanindividualpemilorpermits.G25.SEVERABILITYTheprovisionsofthispermitareseverable,andifanyprovisionofthispermit,orapplicationofanyprovisionofthispemittoanycircumstance.isheldinvalid,theapplicationofsuchprovisiontoothercircumstances,andtheremainderofthispermitshallnotbeaffectedthereby.G26.BYPASSPROffiBITEDA.BypassProceduresBypass,whichistheintentionaldiversionofwastestreamsfron;anyportionofatreatmentfacility,isprohibitedforstorrnwatereventsbelowthedesigncriteriaforstormwatermanagement.EcologymaytakeenforcementactionagainstaPermitteeforbypassunlessoneofthefollowingcircumstances(1,2,3or4)isapplicable.1.Bypassofstormwaterisconsistentwiththedesigncriteriaandpartofanapprovedmanagementpracticeintheapplicablestormwatermanagementmanual.2.Bypassforessentialmaintenancewithoutthepotentialtocauseviolationofpermitlimitsorconditions.Bypassisauthorizedifitisforessentialmaintenanceanddoesnothavethepotentialtocauseviolationsoflimitationsorotherconditionsofthispermit,oradverselyimpactpublichealth.3.Bypassofstorrnwaterisunavoidable,unanticipated,andresultsinnoncomplianceofthispermit.Thisbypassispermittedonlyif:a.Bypassisunavoidabletopreventlossoflife,personalinjury,orseverepropertydamage.“Severepropertydamage”meanssubstantialphysicaldamagetoproperty,damagetothetreatmentfacilitieswhichwouldcausethemtobecomeinoperable,orsubstantialandpermanentlossofnaturalresourceswhichcanreasonablybeexpectedtooccurintheabsenceofabypass.b.Therearenofeasiblealternativestothebypass,suchastheuseofauxiliarytreatmentfacilities,retentionofuntreatedwastes,maintenanceduringnormalperiodsofequipmentdowntime(butnotifadequatebackupequipmentshouldhavebeeninstalledintheexerciseofreasonableengineeringjudgmenttopreventabypasswhichoccurredduringnormalperiodsofequipmentdowntimeorpreventativemaintenance),ortransportofuntreatedwastestoanothertreatmentfacility.ConstructionStormwaterGeneralPermit—December1,2010Page43 C.EcologyisproperlynotifiedofthebypassasrequiredinSpecialConditionS5.fofthispermit.4.Aplannedactionthatwouldcausebypassofstormwaterandhasthepotentialtoresultinnoncomplianceofthispermitduringastormevent.ThePermitteemustnotifyEcologyatleastthirty(30)daysbeforetheplanneddateofbypass.Thenoticemustcontain:a.adescriptionofthebypassanditscauseb.ananalysisofallknownalternativeswhichwouldeliminate,reduce,ormitigatetheneedforbypassing.c.acost-effectivenessanalysisofalternativesincludingcomparativeresourcedamageassessment.d.theminimumandmaximumdurationofbypassundereachalternative.e.arecommendationastothepreferredalternativeforconductingthebypass.f.theprojecteddateofbypassinitiation.g.astatementofcornpliancewithSEPA.h.arequestformodificationofwaterqualitystandardsasprovidedforinWAC173-201A-11O,ifanexceedanceofanywaterqualitystandardisanticipated.i.stepstakenorplannedtoreduce,eliminate,andpreventreoccurrenceofthebypass.5.Forprobableconstructionbypasses,theneedtobypassistobeidentifiedasearlyintheplanningprocessaspossible.TheanalysisrequiredabovemustbeconsideredduringpreparationoftheStormwaterPollutionPreventionPlan(SWPPP)andmustbeincludedtotheextentpractical.Incaseswheretheprobableneedtobypassisdeterminedearly,continuedanalysisisnecessaryuptoandincludingtheconstructionperiodinanefforttominimizeoreliminatethebypass.Ecologywillconsiderthefollowingbeforeissuinganadministrativeorderforthistypebypass:a.Ifthebypassisnecessarytoperformconstructionormaintenance-relatedactivitiesessentialtomeettherequirementsofthispermit.b.Iftherearefeasiblealternativestobypass,suchastheuseofauxiliarytreatmentfacilities,retentionofuntreatedwastes,stoppingproduction,maintenanceduringnormalperiodsofequipmentdowntime,ortransportofuntreatedwastestoanothertreatmentfacility.C.Ifthebypassisplannedandscheduledtominimizeadverseeffectsonthepublicandtheenvironment.ConstructionStonnwaterGeneralPermit—December1,2010Page44 Afterconsiderationofthcaboveandtheadverseeffectsoftheiroioscdbypassandanyotherrelevantfactors,Ecologywillapprove,conditionallyapprove,ordenytherequest.Thepublicmustbenotifiedandgivenanopportunitytocommentonbypassincidentsofsignificantduration,totheextentfeasible.ApprovalofarequesttobypasswillbebyadministrativeorderissuedbyEcologyunderRCW90.48.120.B.DutytoMitigateThePermitteeisrequiredtotakeallreasonablestepstominimizeorpreventanydischargeorsludgeuseordisposalinviolationofthispermitthathasareasonablelikelihoodofadverselyaffectinghumanhealthortheenvironment.ConstructionStoi7nwaterGeneralPermit—December1,2010Page45 APPENDiXA-DEFINiTiONSAKARTisanacronymfor“allknown,available,andreasonablemethodsofprevention.control,andtreatment.”AKARTrepresentsthemostcurrentmethodologythatcanbereasonablyrequiredforpreventing,controlling,orabatingthepollutantsandcontrollingpollutionassociatedwithadischarge.ApplicableTMDLmeansaTMDLforturbidity,finesediment,highpH,orphosphorus,whichwascompletedandapprovedbyEPAbeforeJanuary1,2011,orbeforethedatetheoperator’scompletepermitapplicationisreceivedbyEcology,whicheverislater.Applicantmeansanoperatorseekingcoverageunderthispermit.BestManagementPractices(BMPs)meansschedulesofactivities,prohibitionsofpractices,maintenanceprocedures,andotherphysical,structuraland/ormanagerialpracticestopreventorreducethepollutionofwatersoftheState.BMPsincludetreatmentsystems,operatingprocedures,andpracticestocontrol:stormwaterassociatedwithconstructionactivity,spillageorleaks,sludgeorwastedisposal,ordrainagefromrawmaterialstorage.Buffermeansanareadesignatedbyalocaljurisdictionthatiscontiguoustoandintendedtoprotectasensitivearea.Bypassmeanstheintentionaldiversionofwastestreamsfromanyportionofatreatmentfacility.CalendarDayAperiodof24consecutivehoursstartingat12:00midnightandendingthefollowing12:00midnight.CalendarWeek(sameasWeek)meansaperiodofsevenconsecutivedaysstartingat12:01a.m.(0:01hours)onSunday.CertifiedErosionandSedimentControlLead(CESCL)meansapersonwhohascurrentcertificationthroughanapprovederosionandsedimentcontroltrainingprogramthatmeetstheminimumtrainingstandardsestablishedbyEcology(seeBMPC160intheSWMM).CleanWaterAct(CWA)meanstheFederalWaterPollutionControlActenactedbyPublicLaw92-500,asamendedbyPublicLaws95-217,95-576,96-483,and97-117;USC1251etseq.CombinedSewermeansasewerwhichhasbeendesignedtoserveasasanitarysewerandastormsewer,andintowhichinflowisallowedbylocalordinance.CommonPlanofDevelopmentorSalemeansasitewheremultipleseparateanddistinctconstructionactivitiesmaybetakingplaceatdifferenttimesondifferentschedulesand/orbydifferentcontractors,butstillunderasingleplan.Examplesinclude:1)phasedprojectsandprojectswithmultiplefilingsorlots,eveniftheseparatephasesorfilings/lotswillbeconstructedunderseparatecontractorbyseparateowners(e.g.,adevelopmentwherelotsaresoldtoseparatebuilders);2)adevelopmentplanthatmaybephasedovermultipleyears,butisstillunderaConstructionStormwaterGeneralPermit—December1,2010Page46 consistentpianforlong-termdevelopment;3)projectsinacontiguousareathatmaybeunrelatedbutstillunderthesamecontract,suchasconstructionofabuildingextensionandanewparkinglotatthesamefaci1ityand4)linearprojectssuchasroads,pipelines.orutilities.Iftheprojectispartofacommonplanofdevelopmentorsale,thedisturbedareaoftheentireplaniTlustbeusedindeterminingpermitrequirements.CompositeSamplemeansamixtureofgrabsamplescollectedatthesamesamplingpointatdifferenttimes,formedeitherbycontinuoussamplingorbymixingdiscretesamples.Maybe“time-composite”(collectedatconstanttimeintervals)or‘flow-proportional’(collectedeitherasaconstantsamplevolumeattimeintervalsproportionaltostreamflow,orcollectedbyincreasingthevolumeofeachaliquotastheflowincreaseswhilemaintainingaconstanttimeintervalbetweenthealiquots.Concretewastewatermeansanywaterusedintheproduction,pouringand/orclean-upofconcreteorconcreteproducts,andanywaterusedtocut,grind,wash,orotherwisemodifyconcreteorconcreteproducts.Examplesincludewaterusedfororresultingfromconcretetruck/rnixer/purnper!toollchuterinsingorwashing,concretesawcuttingandsurfacing(sawing,coring,grinding,roughening,hydro-demolition,bridgeandroadsurfacing).Whenstormwatercomingleswithconcretewastewater,theresultingwaterisconsideredconcretewastewaterandmustbemanagedtopreventdischargetowatersofthestate,includinggroundwater.ConstructionActivitymeanslanddisturbingoperationsincludingclearing,gradingorexcavationwhichdisturbsthesurfaceoftheland.Suchactivitiesmayincluderoadconstruction,constructionofresidentialhouses,officebuildings,orindustrialbuildings,anddemolitionactivity.Contaminantmeansanyhazardoussubstancethatdoesnotoccurnaturallyoroccursatgreaterthannaturalbackgroundlevels.Seedefinitionof“hazardoussubstance”andWAC173-340-200.DemonstrablyEquivalentmeansthatthetechnicalbasisfortheselectionofallstormwaterBMPsisdocumentedwithinaSWPPP,including:1.ThemethodandreasonsforchoosingthestormwaterBMPsselected.2.ThepollutantremovalperformanceexpectedfromtheBMPsselected.3.ThetechnicalbasissupportingtheperformanceclaimsfortheBMPsselected,includinganyavailabledataconcerningfieldperformanceoftheBMPsselected.4.AnassessmentofhowtheselectedBMPswillcomplywithstatewaterqualitystandards.5.AnassessmentofhowtheselectedBMPswillsatisfybothapplicablefederaltechnology-basedtreatmentrequirementsandstaterequirementstouseallknown,available,andreasonablemethodsofprevention,control,andtreatment(AKART).DepartmentmeanstheWashingtonStateDepartmentofEcology.Detentionmeansthetemporarystorageofstormwatertoimprovequalityand/ortoreducethemassflowrateofdischarge.ConstructionStormwaterGeneralPermit—December1,2010Page47 Dewateringmeanstheactofpumpinggroundwaterorstorrnwaterawayfromanactiveconstructionsite.DirectormeanstheDirectoroftheWashingtonDepartmentofEcologyorhis/herauthorizedrepresentative.DischargermeansanowneroroperatorofanyfacilityoractivitysubjecttoregulationunderChapter90.48RCWorthefederalCleanWaterAct.DomesticWastewatermeanswatercarryinghumanwastes,includingkitchen,bath,andlaundrywastesfromresidences,buildings,industrialestablishments,orotherplaces,togetherwithsuchgroundwaterinfiltrationorsurfacewatersasmaybepresent.EcologymeanstheWashingtonStateDepartmentofEcology.EngineeredSoilsmeanstheuseofsoilamendmentsincluding,butnotlimited,toPortlandcementtreatedbase(CTB),cementkilndust(CKD),orflyashtoachievecertaindesirablesoilcharacteristics.EquivalentBMPsmeansoperational,sourcecontrol,treatment,orinnovativeBMPswhichresultinequalorbetterqualityofstormwaterdischargetosurfacewaterortogroundwaterthanBMPsselectedfromtheSWMM.Erosionmeansthewearingawayofthelandsurfacebyrunningwater,wind,ice,orothergeologicalagents,includingsuchprocessesasgravitationalcreep.ErosionandSedimentControlBMPsmeansBMPsintendedtopreventerosionandsedimentation,suchaspreservingnaturalvegetation,seeding,mulchingandmatting,plasticcovering,filterfences,sedimenttraps,andponds.ErosionandsedimentcontrolBMPsaresynonymouswithstabilizationandstructuralBMPs.FinalStabilization(sameasfullystabilizedorfullstabilization)meanstheestablishmentofapermanentvegetativecover,orequivalentpermanentstabilizationmeasures(suchasriprap,gabionsorgeotextiles)whichpreventserosion.GroundWatermeanswaterinasaturatedzoneorstratumbeneaththelandsurfaceorasurfacewaterbody.HazardousSubstancemeansanydangerousorextremelyhazardouswasteasdefinedinRCW70.105.010(5)and(6),oranydangerousorextremelydangerouswasteasdesignatedbyruleunderchapter70.105RCW;anyhazardoussub-stanceasdefinedinRCW70.105.010(14)oranyhazardoussubstanceasdefinedbyruleunderchapter70.105RCW;anysubstancethat,ontheeffectivedateofthissection,isahazardoussubstanceundersection101(14)ofthefederalcleanuplaw,42U.S.C.,Sec.9601(14);petroleumorpetroleumproducts;andanysubstanceorcategoryofsubstances,includingsolidwastedecompositionproducts,determinedbythedirectorConstructionStol7nwaterGeneralPermit—December1,2010Page48 byruletopresentathreattohumanhealthortheenvironmentifreleasedintotheenvironment.Thetermhazardoussubstancedoesnotincludeanyofthefollowingwhencontainedinanundergroundstoragetankfromwhichthereisnotarelease:crudeoiloranyfractionthereoforpetroleum,ifthetankisincompliancewithallapplicablefederal,state.andlocallaw.InjectionWellmeansawellthatisusedforthesubsurfaceemplacementoffluids.(SeeWell.)Jurisdictionmeansapoliticalunitsuchasacity,townorcounty;incorporatedforlocalself-government.NationalPollutantDischargeEliminationSystem(NPDES)meansthenationalprogramforissuing,modifying,revokingandreissuing,terminating,monitoring,andenforcingpermits,andimposingandenforcingpretreatmentrequirements,undersections307,402,318,and405oftheFederalCleanWaterAct,forthedischargeofpollutantstosurfacewatersoftheStatefrompointsources.ThesepermitsarereferredtoasNPDESpermitsand,inWashingtonState,areadministeredbytheWashingtonDepartmentofEcology.NoticeofIntent(NOT)meanstheapplicationfor,orarequestforcoverageunderthisgeneralpermitpursuanttoWAC173-226-200.NoticeofTermination(NOT)meansarequestforterminationofcoverageunderthisgeneralpermitasspecifiedbySpecialCondition510ofthispermit.Operatormeansanypartyassociatedwithaconstructionprojectthatmeetseitherofthefollowingtwocriteria:.Thepartyhasoperationalcontroloverconstructionplansandspecifications,includingtheabilitytomakemodificationstothoseplansandspecifications;or.Thepartyhasday-to-dayoperationalcontrolofthoseactivitiesataprojectthatarenecessarytoensurecompliancewithaSWPPPforthesiteorotherpermitconditions(e.g.,theyareauthorizedtodirectworkersatasitetocarryoutactivitiesrequiredbytheSwPPPorcomplywithotherpermitconditions).Permitteemeansindividualorentitythatreceivesnoticeofcoverageunderthisgeneralpermit.llmeansaliquid’smeasureofacidityoralkalinity.ApHof7isdefinedasneutral.Largevariationsaboveorbelowthisvalueareconsideredharmfultomostaquaticlife.pHmonitoringperiodmeansthetimeperiodinwhichthepHofstormwaterrunofffromasitemustbetestedaminimumofonceeverysevendaystodetermineifstonnwaterpHisbetween6.5and8.5.Pointsourcemeansanydiscernible,confmed,anddiscreteconveyance,includingbutnotlimitedto,anypipe,ditch,channel,tunnel,conduit,well,discretefissure,andcontainerfromwhichpollutantsareormaybedischargedtosurfacewatersoftheState.Thistermdoesnotincludereturnflowsfromirrigatedagriculture.(SeeFactSheetforfurtherexplanation.)ConstructionStonnwaterGeneralPerniit—December1,2010Page49 Pollutantmeansdredgedspoil,solidwaste,incineratorresidue,filterbackwash,sewage,garbage,domesticsewagesludge(biosolids),munitions,chemicalwastes,biologicalmaterials,radioactivematerials,heat.wreckedordiscardedequipment,rock.sand,cellardirt,andindustrial,municipal,andagriculturalwaste.Thistermdoesnotincludesewagefromvesselswithinthemeaningofsection312oftheCWA,nordoesitincludedredgedorfillmaterialdischargedinaccordancewithapermitissuedundersection404oftheCWA.Pollutionmeanscontaminationorotheralterationofthephysical,chemical,orbiologicalpropertiesofwatersoftheState;includingchangeintemperature,taste,color,turbidity,orodorofthewaters;orsuchdischargeofanyliquid,gaseous,solid,radioactiveorothersubstanceintoanywatersoftheStateaswillorislikelytocreateanuisanceorrendersuchwatersharmful,detrimentalorinjurioustothepublichealth,safetyorwelfare;ortodomestic,commercial,industrial,agricultural,recreational,orotherlegitimatebeneficialuses;ortolivestock,wildanimals,birds,fishorotheraquaticlife.Processwastewatermeansanywaterwhich,duringmanufacturingorprocessing,comesintodirectcontactwithorresultsfromtheproductionoruseofanyrawmaterial,intermediateproduct,finishedproduct,byproduct,orwasteproduct(40CFR122.1).Receivingwatermeansthewaterbodyatthepointofdischarge.Ifthedischargeistoastormsewersystem,eithersurfaceorsubsurface,thereceivingwateristhewaterbodytowhichthestormsystemdischarges.Systemsdesignedprimarilyforotherpurposessuchasforgroundwaterdrainage,redirectingstreamnaturalflows,orforconveyanceofirrigationwater/returnflowsthatcoincidentallyconveystormwaterareconsideredthereceivingwater.Representativemeansastormwaterorwastewatersamplewhichrepresentstheflowandcharacteristicsofthedischarge.Representativesamplesmaybeagrabsample,atime-proportionatecompositesample,oraflowproportionatesample.Ecology’sConstructionStormwaterMonitoringManualprovidesguidanceonrepresentativesampling.Sanitarysewermeansasewerwhichisdesignedtoconveydomesticwastewater.Sedimentmeansthefragmentedmaterialthatoriginatesfromtheweatheringanderosionofrocksorunconsolidateddeposits,andistransportedby,suspendedin,ordepositedbywater.Sedimentationmeansthedepositingorformationofsediment.Sensitiveareameansawaterbody,wetland,stream,aquiferrechargearea,orchannelmigrationzone.SEPA(StateEnvironmentalPolicyAct)meanstheWashingtonStateLaw,RCW43.21C.020,intendedtopreventoreliminatedamagetotheenvironment.SignificantAmountmeansanamountofapollutantinadischargethatisamenabletoavailableandreasonablemethodsofpreventionortreatment;oranamountofapollutantthathasaConstructionStol7nwaterGeneralPermit—December1,2010.Page50 reasonablepotentialtocauseaviolationofsurfaceorgroundwaterqualityorsedimentmanagementstandards.Significantconcreteworkmeansgreaterthan1000cubicyardspouredconcreteorrecycledconcreteoverthelifeofaproject.SignificantContributorofPollutantsmeansafacilitydeterminedbyEcologytobeacontributorofasignificantamount(s)ofapollutant(s)towatersoftheStateofWashington.Sitemeansthelandorwaterareawhereany“facilityoractivity”isphysicallylocatedorconducted.SourcecontrolBMPsmeansphysical,structuralormechanicaldevicesorfacilitiesthatareintendedtopreventpollutantsfromenteringstorrnwater.AfewexamplesofsourcecontrolBMPsareerosioncontrolpractices,maintenanceofstorrnwaterfacilities,constructingroofsoverstorageandworkingareas,anddirectingwashwaterandsimilardischargestothesanitaryseweroradeadendsump.StabilizationmeanstheapplicationofappropriateBMPstopreventtheerosionofsoils,suchas,temporaryandpermanentseeding,vegetativecovers,mulchingandmatting,plasticcoveringandsodding.SeealsothedefinitionofErosionandSedimentControlBMPs.Stormdrainmeansanydrainwhichdrainsdirectlyintoastormsewersystem,usuallyfoundalongroadwaysorinparkinglots.Stormsewersystemmeansameansaconveyance,orsystemofconveyances(includingroadswithdrainagesystems,municipalstreets,catchbasins,curbs,gutters,ditches,manmadechannels,orstormdrainsdesignedorusedforcollectingorconveyingstormwater.ThisdoesnotincludesystemswhicharepartofacombinedsewerorPubliclyOwnedTreatmentWorks(POTW)asdefinedat40CfR122.2.Stormwatermeansthatportionofprecipitationthatdoesnotnaturallypercolateintothegroundorevaporate,butflowsviaoverlandflow,interfiow,pipes,andotherfeaturesofastormwaterdrainagesystemintoadefinedsurfacewaterbody,oraconstructedinfiltrationfacility.StorrnwaterManagementManual(SWMM)orManualmeansthetechnicalManualpublishedbyEcologyforusebylocalgovernmentsthatcontaindescriptionsofanddesigncriteriaforBMPstoprevent,control,ortreatpollutantsinstorrnwater.StorrnwaterPollutionPreventionPlan(SWPPP)meansadocumentedplantoimplementmeasurestoidentify,prevent,andcontrolthecontaminationofpointsourcedischargesofstormwater.SurfaceWatersoftheStateincludeslakes,rivers,ponds,streams,inlandwaters,saltwaters,andallothersurfacewatersandwatercourseswithinthejurisdictionofthestateofWashington.ConstructionStOl7flWaterGeJ?eralPermit—December1,2010Page51 TemporaryStabilizationmeanstheexposedgroundsurfacehasbeencoveredwithappropriatematerialstoprovidetemporarystabilizationofthesurfacefromwaterorwinderosion.Materialsinclude,butarenotlimitedto,mulch,riprap,erosioncontrolmatsorblanketsandtemporarycovercrops.Seedingaloneisnotconsideredstabilization.Temporarystabilizationisnotasubstituteforthemorepermanent“finalstabilization.”TotalMaximumDailyLoad(TMDL)meansacalculationofthemaximumamountofapollutantthatawaterbodycanreceiveandstillmeetstatewaterqualitystandards.Percentagesofthetotalmaximumdailyloadareallocatedtothevariouspollutantsources.ATMDListhesumoftheallowableloadsofasinglepollutantfromallcontributingpointandnonpointsources.TheTMDLcalculationsmustincludea“marginofsafety”toensurethatthewaterbodycanbeprotectedincasethereareunforeseeneventsorunknownsourcesofthepollutant.Thecalculationmustalsoaccountforseasonablevariationinwaterquality.TreatmentBMPsmeansBMPsthatareintendedtoremovepollutantsfromstormwater.AfewexamplesoftreatmentBMPsaredetentionponds,oil/waterseparators,biofiltration,andconstructedwetlands.Transparencymeansameasurementofwaterclarityincentimeters(cm),usinga60cmtransparencytube.ThetransparencytubeisusedtoestimatetherelativeclarityortransparencyofwaterbynotingthedepthatwhichablackandwhiteSecchidiscbecomesvisiblewhenwaterisreleasedfromavalueinthebottomofthetube.Atransparencytubeissometimesreferredtoasa“turbiditytube.”Turbiditymeanstheclarityofwaterexpressedasnephelometricturbidityunits(NTU)andmeasuredwithacalibratedturbidimeter.Uncontaminatedmeansfreefromanycontaminant,asdefinedinMTCAcleanupregulations.Seedefinitionof”contaminant”andWAC173-340-200.WasteLoadAllocation(WLA)meanstheportionofareceivingwater’sloadingcapacitythatisallocatedtooneofitsexistingorfuturepointsourcesofpollution.WLAsconstituteatypeofwaterqualitybasedeffluentlimitation(40CFR130.2[h]).Waterqualitymeansthechemical,physical,andbiologicalcharacteristicsofwater,usuallywithrespecttoitssuitabilityforaparticularpurpose.WatersoftheStateincludesthosewatersasdefinedas“watersoftheUnitedStates”in40CFRSubpart122.2withinthegeographicboundariesofWashingtonStateand“watersoftheState”asdefinedinChapter90.48RCW,whichincludelakes,rivers,ponds,streams,inlandwaters,undergroundwaters,saltwaters,andallothersurfacewatersandwatercourseswithinthejurisdictionofthestateofWashington.w.llmeansabored,drilledordrivenshaft,ordugholewhosedepthisgreaterthanthelargestsurfacedimension.(SeeInjectionwell.)ConstructionStorrnwaterGeneralPermit—December1,2010Page52 \Vheelwashwastewateriieansanywaterusedin,orresultingfromtheoperationof,atirebathofwheelwash(BMPC106:WheelWash),orotherstructureorpracticethatuseswatertophysicallyremovemudanddebrisfromvehiclesleavingaconstructionsiteandpreventtrack-otitontoroads.Whenstormwatercomingleswithwheelwashwastewater,theresultingwaterisconsideredwheelwash1astewaterandmustbemanagedaccordingtoSpecialConditionS9.D.9.ConstructionStorrnwaterGeneralPermit—December1,2010Page53 APPENDiXB-ACRONYMS....AKARTAllKnown,Available,andReasonableMethodsofPrevention.Control,andTreatmentBMPBestManagementPracticeCESCLCertifiedErosionandSedinientControlLeadCFRCodeofFederalRegulationsCKDCementKilnDustcmCentimetersCTBCement-TreatedBaseCWACleanWaterActDMRDischargeMonitoringReportEPAEnvironmentalProtectionAgencyESCErosionandSedimentControlFRFederalRegisterNOTNoticeofIntentNOTNoticeofTerminationNPDESNationalPollutantDischargeEliminationSystemNTUNephelometricTurbidityUnitRCWRevisedCodeofWashingtonSEPAStateEnvironmentalPolicyActSWMM$tormwaterManagementManualSwPPPStormwaterPollutionPreventionPlanTMDLTotalMaximumDailyLoadUICUndergroundInjectionControlUSCUnitedStatesCodeUSEPAUnitedStatesEnviromnentalProtectionAgencyWACWashingtonAdministrativeCodeWQWaterQualityWWHMWesternWashingtonHydrologyModelConstructionStOl7flWaterGeneralPermit—December1,2010Page54 AppendixFEngineeringCalculationsEXISTINGSITEHYDROLOGYKCRTSwasusedtomodelthepeakrunofffromtheSite.PerTable3.2.2,boftheManualthesoiltypeforthemajorityofthesiteismodeledas‘Till”fortheAlderwoodgravellysandyloamscsclassificationasshowninFigure4.Soils.TheentireProjectismodeledas“Forest.”ResultsoftheKCRTSanalysisareincludedinthissection.ModelingInputTable1Pre-DevelopedKCRTSModelingInputModelingResultsSITEFlowFrequencyAnalysisTimeSeriesFile:predev.tsfProjectLocation:Sea-TacSedimentTrapFacilitySizingTheSitewillutilizetwosedimenttrapsforsedimentcontrol.Themaximumdischargerateforthesiteis0.0815cfs(50%ofthe2-yearpredevelopedpeak).Thenorthernsedimenttrapwillpumpstormwatertotheproposedoutfallconveyancesystem.Thesouthernsedimenttrapwilloverflowrunoffintotheproposedtreeretentiontract.D.R.STRONGConsultingEngineers,Inc.StormwaterPollutionPreventionPlanVuecrestEstates&VuecrestIIShortPlatLandcoverTillForest(ac)I5874TillGrass(ac)OutwashForest(ac)L_lmpervious(ac)ScaleFactor:TimeStep:DataType:Projectlocation:0.0000.000-0.0001.00-HourlyReducedSeatacTotalArea:I5.874---AnnualPeakFlowRates---FlowFrequencyAnalysisFlowRateRankTimeofPeak--Peaks--RankReturnProb(CFS)(CFS)Period0.37022/09/0118:000.4741100.000.9900.10071/06/023:000.370225.000.9600.27542/28/033:000.284310.000.9000.01083/24/0420:000.27545.000.8000.16361/05/058:000.24053.000.6670.28431/18/0621:000.16362.000.5000.240511/24/064:000.10071.300.2310.47411/09/089:000.01081.100.091ComputedPeaks0.43950.000.980PageF-2 Belowissizingsummary:SedimentTrapI:2yearpeakflowrate:RequiredSurfaceArea:ProvidedSurfaceArea:2.95acrestofcfs2,225sf.2,650s.fSedimentTrap2:2yearpeakflowrate:RequiredSurfaceArea:ProvidedSurfaceArea:217acresO591cfsI,2305!.2,000s.f.D.R.STRONGConsultingEngineers,Inc.StormwaterPollutionPreventionPlanVuecrestEstates&VuecrestIIShortPlatPageF-2 APPENDIX“C”BONDQUANTITYWORKSHEET©2015D.R.STRONGConsultingEngineersInc.VuecrestEstates&VuecrestIIShortPlatPage64TechnicalInformationReportCityofRenton —‘RentonBONDQUANTITYWORKSHEETINSTRUCTIONSConiinunity&ECOflOIHiCi)cvelopmentPlanningDivision/1055SouthGradyWay—6thFloor/Renton,WA9O57(425)430-7200Thisworksheetisintendedtobeaworkingcopyofthebondquantityworksheet,whichwillbeusedthroughoutaliphasesoftheproject,frominitialsubmittaltoprojectclose-outapprovaLSubmitthisworkbook,initsentirety,asfollows:.(1)electroniccopyand(2)hardcopiesoftheentireworkbookforcivilconstructionpermitsubmittalHardcopiesaretobeIncludedaspartoftheTechnicalInformationReport(TIR)..(1)electroniccopyand(1)hardcopyoftheentireworkbookforfinalclose-outsubmittal.Thefollowingformsaretobecompletedbytheengineer/developer/applicantasapplicabletotheproject:SectionI:ProjectInformation.Thissectionincludesallpertinentinformationfortheproject.Thissectionmustbecompletedinitsentirety.Informationfromthissectionauto-populatestoallotherrelevantareasoftheworkbookSectionII:BondQuantitiesWorksheets.SectionIIcontainsaseparatespreadsheetTABforeachofthefollowingspecialties:.Sectionll.aEROSIONCONTROL(Stabilization/ErosionSedimentControl(ESC)).Sectionll.bTRANSPORTATION(StreetandSiteImprovements).Sectionll.cDRAINAGE(DrainageandStormwaterFacilities):.Sectionll.dWATER-ONLYAPPLICABLEIFWATERSERVICEiSPROVIDEOBYCITYOFRENTON.SectionI.eSANITARYSEWER-ONLYAPPLICABLEIFSEWERSERVICEISPROVIOEDBYCITYOFRENTON.CompletetheQuantitycolumnsforeachoftheappropriatesection(s).IncludeexistingRight-of-Way(ROW),FuturePublicImprovementsandPrivateImprovements..Note:Privateimprovements,withtheexceptionofstormwaterfacilities,arenotIncludedInthebondamountcalculation,butmustbeenteredontheform.Stormwaterfacilities(publicandprivate)arerequiredtobeincludedinthebondamount..The‘QuantityRemaining’columnisonlytobeusedwhenaprojectisunderconstruction.TheCityallowsone(1)bondreductionduringthelifeoftheprojectwiththeexceptionofthemaintenanceperiodreduction..Excelwillauto-calculateandauto-populatetherelevantfieldsandsubtotalsthroughoutthedocument.Onlythe‘Quantity’columnsshouldneedcompleting..Additionalitemsnotincludedinthelistscanbeaddedunderthe“write-in”sections.Provideacompletedescription,costestimateandunitofmeasureforeachwrite-initem..Allunitpricesincludelabor,equipment,materials,overheadandprofit.TheBondWorksheetformwillauto-cakulateandauto-populatefromtheinformationprovidedinSection1andSectionII.SectionIII.BondWorksheet.ThissectioncalculatestherequiredPermitBondforconstructionpermitissuanceaswellastherequiredMaintenanceBondforprojectclose-outsubmittalstoreleasethepermitbondonaproject.unitPricesUpdated:03/2016Page1of14Version:06/2016Ref8-HBondQuantityWorksheetINSTRUCTIONSPrinted8/26/2016 SITEIMPROVEMENTBONDQUANTITYWORKSHEETPROJECTINFORMATION—“RentonCo;munity&EconomicPlanningDivision/1055SouthGradyWay—6thFloar/Renton,WA98057(425)430-7200DeVelopiTlentDatePrepared:17/25/2016pProjectPhaseFORAPPROVALPreparedby:EngineerStampRequiredName:MaherA.Joudi(allcostestimatesmusthaveoriginalwetstampandsignature)PERegistrationNo:45232FirmName:DR.STRONGConsultingEngineers,Inc.FirmAddress:6207thAvenuePhoneNo.425.827.3063EmailAddress:maher.joudi@drstrong.comProjectLocationandDescriptionProjectOwnerInformationProjectName:VuecrestEstatesProjectOwner:HarbourHomes,LLCCEDPlanIt(LUA):LUA3-000642Phone:206315.8130CEDPermit11(U):U15007217Address:400N34thStreet,Suite300SiteAddress:SmithersAveS&S47thStSeattle,WA98103StreetIntersection:Addt’lProjectOwner:N/AParcelIt(s):3123059048Phone:AbbreviatedLegalPARCELCOFRENTONLLAeLUAO2O451.LAREC2OO2O8239OOOO3Address..LOCATEDINNE1/4OF5E1/4OFSDSECDescription:ClearingandGradingUtilityProvidersClearingandgradinggreaterthanorequalto5,000boardfeetoftimber?Yes/No:INOIWaterServiceProvidedby:5005CREEKWATER&SEWERIfYes,ProvideForestPracticePermitU:IN/AISewerServiceProvidedby:CITYOFRENTON1Selectthecurrentprojectstatus/phasefromthefollowingoptions:ForApproval-PreliminaryDataEnclosed,pendingapprovalfromtheCity;ForConstructionEstimatedDataEnclosed,PlanshavebeenapprovedforcontructionbytheCity;ProjectCloseout-FinalCostsandQuantitiesEnclosedforProjectClose-outSubmittalunitPricesUpdated:06/14/2016Page2of14version:06/14/2016Ref8-HBondQuantityworksheetSECTIONIPROJECTINFORMATIONPrinted8/26/2016 CEDPermit#:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFOREROSION&SEDIMENTCONTROLEROSION/SEDIMENTSUBTOTAL:69,333.40SALESTAX@9.5%6,586.67EROSION/SEDIMENTTOTAL:75,920.07(A)UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016Unit(A)DescriptionNo.Reference#PriceUnitQuantityCostBackfill&compaction-embankmentESC-16.50CVCheckdams,4”minusrockESC-2SWDM5.4.6.380.00Each9720.00CatchBasinProtectionESC-335.50Each26923.00Crushedsurfacing11/4’minusESC-4WSDOTO-03.9(3)95.00CVDitchingESC-59.00CVlii1,017.00Excavation-bulkESC-62.00CVFence,slitESC-7SWDM54.3.11.50LF15982,397.00Fence,Temporary(NOPE)ESC-81.50LF12501,875.00GeotextileFabricESC-92.50SVHayBaleSiltTrapESC-100.50EachHydroseedingESC-11SWDM£42.40.80SV2103316,826.40InterceptorSwaleIDikeESC-1Z100LFJuteMeshESC-13SWDMS.4.2.2350SYLevelSpreaderESC-141.75LFMulch,byhand,straw,3”deepESC-15SWDM5.4.2.12.50SYMulch,bymachine,straw,2”deepESC-16SWDMS4.2.12.00SY750015,000.00Piping,temporary,CPP,6”ESC4712.00LFPiping,temporary,CPP,8’ESC-1814.00LFPiping,temporary,CPP,12”ESC4918.00LF1302,340.00Plasticcovering,6mmthick,sandbagged[SC-20SWDM5.4.2.34.00SY8853,540.00RipRap,machineplaced;slopesESC-21W5D0T943.1(2)45.00CVRockConstructionEntrance,50’x15’xl’ESC-22SWDM5.4.411,800.00EachRockConstructionEntrance,100’x15’xl’ESC-23SWDM5.4.4.13,200.00Each13,200.00SedimentpondriserassemblyESC-24SWDM5.4.5.22,200.00EachSedimenttrap,5’hIghbermESC-25SWDM5.4.5.119.00LF3256,175.00Sed.trap,5’high,riprappedspillwaybermsectIonESC-26SWDM5.4.5.170.00LF6420.00Seeding,byhandESC-27SWDMS.4.2.41.00SVSodding,1”deep,levelgroundESC-28SWDM5.4.2.58.00SYSodding,1”deep,slopedgroundESC-29SWDM54.2.510.00SYTESCSupervisorESC-303110.00HR808,800.00Watertruck,dustcontrolESC-31SWDM5.4.73140.00HR405,600.00UnitWRITE-IN-ITEMSReference#PriceUnitQuantityCostSedimentTrapPump$50000Each1500.00Page3ofl4Ref8-HBondQuantityWorksheetSECTIONl.aEROSION_CONTROL Page4ofl4Ref8-HBondQuantityWorksheetSITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSTREETANDSITEIMPROVEMENTSSUBTOTALTHISPAGE:(F)UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007217ExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction)181CIID))E)DescriptionINo.UnitPriceUnitQuant.ICostQuant.CostQuant.ICostQuant.ICostEENERALITEMSackfill&Compaction-embankmentGl-1$6.00CY571934,314.00ackfill&Compaction-trenchG(-2$900CV49441.008027,218.00lear/RemoveBrush,byhand(SY)$100SYoI(ards-fixed24074Eachol(ards-removab(e452.34Eachearine/Grubbing/TreeRemoval10,00000Acre1.6816,800.0026726,700.00)n-bulk200CY1610532,210.00)n-Trench500CY49245.006024,010.00,cedar,6’high2000LF,chainlink,4’3$_3114,366.25—-chainlink,vinylcoated,6’high20.00LF,chainlink,gate,vinylcoated,20’1,400.00Each:ompact-commonbarrow25.00CYompact-gravelbase27.00CVompact-screenedtopsoil39.00CV12”deep,stonefilledmesh65.00SY,18”deep,stonefilledmesh90.00SY,36”deep,stonefilledmesh15000SVg,fine,byhand$2.50SV8,fine,withgrader200SViients,3’Long250.00Each82,000.00yeAreasSign$700—175.00g,1”deep,slopedground$8.00SVng,line&grade850.00Day6,800.00ng,lotlocation/lines$1,800.00Acre2674,806.00TypeA(imported)1-26S28.50CVcontrolcrew(2flaggers)(-27$12000HR,4”chIppedwood1-28$800SV-4”crushedcinder-29$9.00SV,4”topcourse1-30$1200SVduit,2”-31$5.00IF,retaining,concrete-32$55.00SF603,300.00all,rockery1-33$1500SFI686.00I114,218.25II38,481.00I(B)(C)ID)SECTIONll.bTRANSPORTATION UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSTREETANDSITEIMPROVEMENTSExistingFuturePublicPrivateQuantityRemainingRight-of-wayImprovementsImprovements(BondReduction((B)(C)(0))E)DescriptionINo.UnitPriceUnitQuant.ICostQuant.ICostQuant.ICostQuant.ICostCADIMPROVEMENTJPAVEMENT/SURFACINGrinding,4widemachine<l000sy-1$30.00SYGrinding,4’widemachine1000-2000sy-2$16.0051Grinding,4’wIdemachine>2000sy-3$1000SYCRemoval/Disposal-4$3500SY78227,370.00rricade,Typelii(Permanent)-5$56.00LFrURail-6$30.00LF1504,500.00b&Gutter,rolled-7$17.00LFb&Gutter,vertical-8$12.50LF150018,750.00andGutter,demolitionanddisposal-9$1800LF2103,780.00b.extrudedasphalt-10$5.50LFb.extrudedconcrete-11$7.00LF,asphalt,3”depth-12$1.85LF3259.20,concrete,per1”depth-13$3.00LF,asphalt-14$2.00LF3264.00er,gravel,4”thick-15$15.00SYIt,4”thick-16$38.00SY52720,026.001k,4”thick,demolitionanddisposal-17$32.00SY1k,5”thick-18$41.00SY1375,617.001k,5”thick,demolitionanddisposal-19$40.00SYgn,Handicap-20$85.00Eachriping,perstali-21$7.00Eachriping,thermoplastic,(forcrosswalk)-22$3.00SFriping,4’reflectorizedline-23$0.50IFdditional25”CrushedSurfacing-24$3.60SYMA1/2’Overlay1.5”-25$14.00SYMA1/2”Overlay2”-26$18.00SYMARoad,2”,4”rock,First2500SY-27$2800SYMARoad,2”,4”rock,Qty.over2500SY-28$21.00SYMARoad,4”,6’rock,First2500SY-29$45.00SY2500112,500.00MARoad,4”,6”rock,Qty.over2500SY-30$37.00SY1224,514.00MARoad,4”,4.5”ATB-31$38.00SYaye)Road,4”rock,First2500SY-32$1500SYravelRoad,4”rock,Qty.over2500SY-33$10.00SYhickenedEdge-34$8.60IFSUBTOTALTHISPAGE:I27,493.20j169,687.00f1I(BIcci(Di(ElPage5of14Ref8-HBondQuantityWorksheetSECTiONll.bTRANSPORTATION SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSTREETANDSITEIMPROVEMENTSSTREETANDSITEIMPROVEMENTSSUBTOTAL:SALESTAX@9.5%STREETANDSITEIMPROVEMENTSTOTAL:I28,179.20II348,355.JI74,706.00I2,677.02I33,093.757,097.07II30,856.22jI381,449.001I$1,803.07(B)(C)fD)IIIIIIc)Page6of14UnitPricesUpdated:06/14/2016Version:06/14/2016CEDPermit#:U15007217ExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovementsI(BondReduction)(B)(Cl(DlIIE)DescriptionINo.IUnitPriceIUnitQuant.ICostQuant.ICostQuant.ICostLQuant.ICostPARKINGLOTSURFACINGNo.,,AC,2’topcourserock&4”borrowPL-1$21.00SY‘:AC,1.5”topcourse&25”basecoursePL-2$28.00SY,,selectborrowPL-3$5.00SY.5”topcourserock&2.5”basecoursePL-4$14.00SYSUBTOTALPARKINGLOTSURFACING:IIIIIII(B)(CI(D)IE)LANDSCAPING&‘No.—__________ ____StreetTreesLA-i$20000Each163,200.00MedianLandLA-2Right-of-WayLandscapingLA-3$50.00SY42521,250.00WetlandLandscapingLA-4$17.25SY210036,225.00SUBTOTALLANDSCAPING&VEGETATION:III24,450.00II36,225.00II8)(C)ID)(ElTRAFFIC&LIGHTINGNo.SignsTR-1$200.00Each204,000.00StreetLightSystemf#ofPoles)TR-2$3,000.00Each1236,000.00TrafficSignalTR-3TrafficSignalModificationTR-4SUBTOTALTRAFFIC&LIGHTING:III40,000.00IIII(B)(C)ID)(ElSUBTOTALWRITE-INITEMS:II1IIIIIRef8-HBondQuantityWorksheetSECT1ON(i.bTRANSPORTATIONPrinted8/26/2016 CEDPermit:U15OO7217Page7of14Ref8-HBondQuantityWorksheet(C)UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction((B)(C)(D)i)DescriptionINo.UnitPriceJUnitCostQuant.CostQuant.CostQuant.CostDRAINAGE)CPE=CorrugatedPolyethylenePipeNilorEivalent)ForCuIv-tp,icrcoverwasassursdAssumeperforatedPVCissolidpipe.)AccessRoad,R/DD-1$26.ODSY2406,240.00e(CBSincludeframeandlid)Beehive-2$90.00EachThrough-curbInletFramework-3$400.00EachCBTypeI-4$1,500.00Each1116,500.0069,000.00CsTypeIL-5$1,750.00EachCBTypeH,48’diameter-6$2,300.00Each12,300.00613,800.00-7480.00FT3.671,761.60-12foradditionaldepthover4’-13850.00FTICBTypeII,96’diameter-14$14,000.00Eachforadditionaldepthover4’-15925.00FTRack,12-16350.00EachTrashRack,15’-17410.00EachTrashRack,lB-18$480.00EachTrashRack,21”-19550.00EachCleanout,PVC,4”-20$150.00EachCleanout,PVC,6”-21170.00Each142,380.00-22$200.00EachCulvert,PVC,36’(NotallowedinROW)-31Culvert,CMP,8”-32$19.00CFCulvert,CMP,12”-33$29.00LFSUBTOTAITHISPAGE:I4,061.60I(B)I47,690.40(C)I21,078.00(0)SECTIONIl.cDRAINAGE UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit8:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESKAPfl”,CMP,36’‘CMP,48’ExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovementsBondReductioni(8)IC))D))E)DescriptionINo.IUnitPriceIUnitQuant.ICostQuant.ICostQuant.ICostQuant.(Cost,Concrete,48”,CPE,6”(NotallowedinROW),CPE,8”(NotallowedinROW),CPE,12”(NotallowedinROW)CPE,15”(NotallowedinROW)78.00LF130.00CF190.00LFCFCFCFLFCF205.00CF14.00CF16.00CF24.00IF35.00CFCFCF144.00156.00LF168.00IFulvert,CCPE,36”ulvert,LCPE,48”ulvert,CCPE,54”SUBTOTACTHISPAGE:Page8of14Ref$HBondQuantityWorksheetIII78,300,00(B)(C)(0)SECTION)l.cDRAINAGE Culvert,LCPE,60Culvert,LCPE,72Culvert,HDPE,6’Culvert,HDPE,8’Culvert,HDPE,12’Culvert,HDPE,15”Culvert,HDPE,18”Culvert,HOPE,24”Culvert,HDPE,30”Culvert,HDPE,36”Culvert,HDPE,48”Culvert,HOPE,54”Culvert,HOPE,60”Culvert,HDPE,72”Pipe,Polypropylene,6”Pipe,Polypropylene,8”Pipe,Polypropylene,12”Pipe,Polypropylene,15”Pipe,Polypropylene,18”Pipe,Polypropylene,24”Pipe,Polypropylene,30”Pipe,Polypropylene,36”Pipe,Polypropylene,48”Pipe,Polypropylene,54”Pipe,Polypropylene,60”Pipe,Polypropylene,72”Culvert,Dl,6”Culvert,Dl,8”Culvert,Dl,12”Culvert,Dl,15”Culvert,Dl,18”Culvert,Dl,24”Culvert,Dl,30”Culvert,Dl,36”Culvert,Dl,4$”Culvert,Dl,54”Culvert,Dl,60”Culvert,Dl,72”0-69$180.00LF0-70$192.00LFD-71$42.00LFD-72$42.00LFD-73$74.00IF0-74$10600LFD-75$138.00LF0-76$221.00LFD-77$276.00IFD-7$$331.00IFD-79538600IF0-80S441.00IFD-81$496.00IFD-82$551.00IFD-835$4.00IF0-84$89.00IFD-$5$95.00IFD-86$100.00IFD87$106.00IFD-$8$11100IF----D-$9$11900IFD-90$15400IF0-91$226.00IFD-92$332.00IFD-93$439.00IFD-94$545.00IF0-95$61,00IF0-96$$4.00IFD-97$106.00IF0-98$129.00IF0-99$15200IF0-100$175.00IFD-101$198.00IF0-102$220.00IF0-103$243.00IF0-104$266.00IF0-105$289.00IF0-106$311.00IFSUBTOTALTHISPAGE:tuantitynemainingBondReduction)(E)IIII(0)ElPage9ofl4Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016CEDPermit#:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivate‘‘•Right-of-WayImprovementsImprovements)O)ciOescriptionINo.IUnitPriceIUnitQuant.ICostQuant.ICostQuant.ICostQuant.CostDRAINAGE(Continued)2543918,796.004,134.00III22,930.00IlB)(C)SECTION(l.cORAINAGEPrinted8/26/2016 Page10of14Ref8-HBondcluantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016PrintedB/26/2016CEDPermit#:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction)10)(C)(D)IEIDescriptionINo.UnitPriceUnitQuant.CostQuant.CostQuant.CostDuanE.CostSpecialtyDrainageItemsDitchingSD-i$950CVFlowDispersalTrench(1,436base÷(SD-3$28.00LFFrenchDrain(3depth)SD-4$26.00LFGeotextile,(aidintrench,polypropyleneSD-S$300SYMid-tankAccessRiser,48”dia,6’deep50-6S2,00000EachPondOverflowSpillway50-7$16.00SYRestrictor/OilSeparator,12”SD-B$1,150.00EachRestrictor/Oi(Separator,15”SD-9$1,350.00EachRestrictor/OllSeparator,18”SD4O$1,70000EachRiprap,placedSD-il$42.00CVTankEndReducer(36”diameter)SD-Il$1,200.00EachInfiltrationpondtesting50-13$12500HRPermeablePavement50-14PermeableConcreteSidewalkSD-15Culvert,BoxxftSD-16SUBTOTALSPECIALTYDRAINAGEITEMS:(B)(C)(D)ISTORMWATER.ZJ...-.dFIUvvacer.IraIII1yummaryneeiFACIIITIFS(IncludeFInNControl‘‘-QualityDetentionPondSF-iEachIIDetentionTankSF-2IDetentionVaultSF-3S’””IInfiltrationPondSF-4EachIInfiltrationTankSF-5EachIInfiltrationVaultSF-6EachIInfiltrationTrenchesSF-7EachIBasicBiofiltrationSwaleSF-BEachiofiltrationSwaleSF-9EachWetpondSF-bEachWetvaultSF-ilEachSandFilterSF-12EachSandFilterVaultSF-13EachLinearSandFilterSF44EachStormFilterSF45EachRainGardenSF-16Eachavu,uw.vvI(El(Eland5ktrh1iI300,000.00I(C)SUBTOTALSTORMWATERFACILITIES:I(DI(B(SECTIONII.cDRAINAGE SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESDRAINAGEANDSTORMWATERFACILITIESSUBTOTALSALESTAX@9.5%DRAINAGEANDSTORMWATERFACILITIESTOTAL:4,06160I385.85II4,447.45I(B)I505,990.401I48,069.091I554,059.49I(C)I21,078.00II2,002.41II23,080.41I(0)IIIIII(B)Page11of14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007217ExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction0)Ic)(0)E)DescriptionINo.UnitPriceIUnitQuant.ICostQuant.ICostQuant.ICostQuant.ICostWRITE-IN-ITEMSCONTECHSing(eRadiusArch-1$80,000.00Each180,000.00-4(-5-8-10-11-12-13-14-15SUBTOTALWR(TE-(N(TEMS:.80,000.00IISECF(ON)(.cORA(NAGE Page12of14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORWATERExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction((B)IC)(0)(E)DescriptionNo.UnitPriceUnitQuant.CostQuant.CostQuant.CostQuant.CostConnectiontoExistingWatermainW-12,000.00EachDuctileIronWatermain,CL52,4InchDiameterW-250.00LFDuctileIronWatermain,CL52,6InchDiameterW-356.00LFDuctileIronWatermain,CL52,8InchDiameterW-460.00LFDuctileIronWatermaln,CL52,10InchDiameterW-570.00LFDuctileIronWatermaln,CL52,12InchDiameterW-680.00LFGateValve,4InchDiameterW-7$500.00EachGateValve,6inchDiameterW-8$700.00EachGateValve,8InchDiameterW-9$$00.00EachGateValve,10InchDiameterW-101,00000EachGateValve,12InchDiameterW-111,200.00EachFireHydrantAssemblyW-124,000.00EachPermanentBlow-OffAssemblyW-131,800.00EachAir-VacAssembly,2-InchDiameterW-142,000.00EachAir-VacAssembly,1-InchDiameterW-151,500.00EachCompoundMeterAssembly3-inchDiameterW-16S8,000.00EachCompoundMeterAssembly4-inchDiameterW-179,000.00EachCompoundMeterAssembly6-inchDiameterW-1810,000.00EachPressureReducingValveStation8-inchto10-inchW-1920,000.00EachWATERSUBTOTAL:IIIIIIISALESIAX@95%IIIIIIIIWATERTOTAL:IIIIIIII(B)(C)fD)(E)SECTIONIl.dWATER UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007217SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSANITARYSEWERExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction((B)(C)DlIF)DescriptionNo.UnitPriceUnitQuant.CostQuant.CostQuant.CostQuant.CostCleanOuts-1,00o002020,000.00GreaseInterceptor,500gallon-28,000.00EachGreaseInterceptor,1000gallon-3$10,000.00EachGreaseInterceptor,1500gallon-4$15,000.00EachSideSewerPipe,PVC.4InchDiameter-5$80.00IFSideSewerPipe,PVC.6InchDiameter-6$95.00LF69566,025.00SewerPipe,PVC,8inchDiameter-7$105.00IF1100115,500.00SewerPipe,PVC,12InchDiameter-8$120.00LFSewerPipe,Dl,8InchDiameter-9$115.00IFSewerPipe,Dl,12InchDiameter5-10$130.00IFManhole,48InchDiameter-116,000.00Each848,000.00Manhole,54InchDiameter-136,500.00EachManhole,60InchDiameter-157,500.00EachManhole,72InchDiameter-178,500.00EachManhole,96inchDiameter-19$14,000.00EachPipe,C-900,12InchDiameter-21$180.00IFOutsideDrop-24$1,500.0015InsideDrop-25$1,000.00ISSewerPipe,PVC,InchDiameter-26liftStation(EntireSystem)-2i‘13’SANITARYSEWERSUBTOTAL:[1I163,500.00II86,025.00IISALESTAX@9.5%1II15,532.50II8,172.38]IISANITARYSEWERTOTAL:III179,032.50II94,197.3$jLIlBl(C)101IE)Page13of14Ref8-HBondQuantityWorksheetSECTIONI.eSANITARYSEWER CITYOFSITEIMPROVEMENTBONDQUANTITYCommunity&EconomicPlanningDivision/1055SouthGradyWay—6thFloorIRenton,WA98057(425)430-7200I)evelopmentDate:7/25/2016Preparedby:ProjectInformationName:MaherA.JoudiProjectName:VuecrestEstatesPERegistrationNo:45232cEoPlanIIILUAI:LUA13000642FirmName:DR.STRONGConsultingEngineers,Inc.CEDPermit#(U):U15007217FirmAddress:6207thAvenueSiteAddress:SmithersAveS&S47thStPhoneNo.425827.3063Parcel#ls):3123059048EmailAddress:maher.joudi@drstrong.comProjectPhase:FORAPPROVALCONSTRUCTIONBONDMAINTENANCE(priortopermitissuance)(afterfinalacceptanceofconstruction)SiteRestoration/ErosionSedimentControlSubtotalal$75,920.07lal$75,920.07ExistingRight-of-WayimprovementsSubtotallbl[30,856.22fb)$30,856.22FuturePublicImprovementsSubtotalId$560,481.50Id[s560,481.50Stormwater&DrainageFacilitiesSubtotalIdI$581,587.35ldl$581,587.35BondReduction(QuantityRemaining)2(e)$.(e)$-SiteRestorationlalxisO%113,880.11CivilConstructionPermitllbl+lcl+ldlla150%1,759,387.61MaintenanceBondEST1t$234,585.01Iib)l’)‘(Ut2%Bond2Sf.I(e)o150%ConstructionPermitBondAmountT$1,873,267.72(P+R-S)MinimumBondAmountis$10,000.001EstimateOnly-Mayinvolvemultipleandvariablecomponents,whichwillbeestablishedonanindividualbasisbyDevelopmentEngineering.STheCityofRentonallowsonerequestonlyforbondreductionpriortothemaintenanceperiod.Reductionofnotmorethan70%oftheoriginalbondamount,providedthattheremaining30%willcoverallremainingitemstobeconstructed,3RequiredBondAmountsaresubjecttoreviewandmodificationbyDevelopmentEngineering.,Note:ThewordBONDasusedinthisdocumentmeansanyfinancialguaranteeacceptabletotheCityofRenton.‘5Note:Allpricesincludelabor,equipment,materials,overheadandprofit.tntPricesUpdated:00/14/2015Pagel4of14versIon:06/14/2016RefO.HBondQuantityWorksheetSECTIONIII.BONDWORKSHEETPrinted0/26/2016 —RentonBONDQUANTITYWORKSHEETINSTRUCTIONS(;iunity&FeOflOflhltI)evelf)PlhhCIhtPlanningDivision/1055SouthGradyWay—6thFloor/Renton,WA92057(425)430-7200Thisworksheetisintendedtobeaworkingcopyofthebondquantityworksheet,whichwillbeusedthroughoutallphasesoftheproject,frominitialsubmittaltoprojectclose-outapprovaLSubmitthisworkbook,initsentirety,asfollows:.(1)electroniccopyand(2)hardcopiesoftheentireworkbookfordviiconstructionpermitsubmittal.HardcopiesaretobeIncludedaspartoftheTechnicalInformationReport(TIR)..(1)electroniccopyand(1)hardcopyoftheentireworkbookforfinalclose-outsubmittal.Thefoiowingformsaretobecompletedbytheengineer/developer/applicantasapplicabletotheproject:SectionI:ProjectInformation.Thissectionincludesallpertinentinformationfortheproject.Thissectionmustbecompletedinitsentirety.Informationfromthissectionauto-populatestoallotherrelevantareasoftheworkbookSectionII:BondQuantitiesWorksheets.SectionIIcontainsaseparatespreadsheetTABforeachofthefollowingspecialties:.Sectionll.aEROSIONCONTROL(Stabilization/ErosionSedimentControlfESC)).Sectionll.bTRANSPORTATION(StreetandSiteImprovements).SectionII.cDRAINAGE(DrainageandStormwaterFacilities):.SectionlI.dWATER-ONLYAPPLICABLEIFWATER5ERWCEIsPROVIOEOBYCITYOFRENTON.SectionlI.eSANITARYSEWER-ONLYAPPL1CABLEIFSEWERSERVICEISPROVIDEDBYCITYOFRENTON.CompletetheQuantity’columnsforeachoftheappropriatesection(s).IncludeexistingRight-of-Way(ROW),FuturePublicImprovementsandPrivateImprovements..Note:Privateimprovements,withtheexceptionofstormwaterfacilities,arenotincludedinthebondamountcalculation,butmustbeenteredontheform.Stormwaterfacilities(publicandprivate)arerequiredtobeincludedinthebondamount..TheQuantityRemainingcolumnisonlytobeusedwhenaprojectisunderconstruction.TheCityallowsone(1)bondreductionduringthelifeoftheprojectwiththeexceptionofthemaintenanceperiodreduction..Excelwillauto-calculateandauto-populatetherelevantfieldsandsubtotalsthroughoutthedocument.Onlythe‘Quantity’columnsshouldneedcompleting..Additionalitemsnotincludedinthelistscanbeaddedunderthe‘write-in’sections.Provideacompletedescription,costestimateandunitofmeasureforeachwrite-initem..AllunitpricesIncludelabor,equipment,materials,overheadandprofit.TheBondWorksheetformwillauto-cakulateandauto-populatefromtheinformationprovidedinSectionIandSectionII.SectionIII.BondWorksheet.ThissectioncalculatestherequiredPermitBondforconstructionpermitissuanceaswellastherequiredMaintenanceBondforprojectclose-outsubmittalstoreleasethepermitbondonaproject.unitPricesupdated:03/2016Page1of14Version:06/2016Ref8-HBondQuantityWorksheetINSTRUCTIONSPrinted8/26/2016 SITEIMPROVEMENTBONDQUANTITYWORKSHEETPROJECTINFORMATIONPlanningDivision/1055SouthGradyWay—6thFloar/Renton,WA98057(425)430-72001Selectthecurrentprojectstatus/phasefromthefollowingoptions:ForApproval-PreliminaryDataEnclosed,pendingapprovalfromtheCity;ForConstruction-EstimatedDataEnclosed,PlanshavebeenapprovedforcontructionbytheCity;ProjectCloseout-FinalCostsandQuantitiesEnclosedforProjectClose-outSubmittalPage2of14Ref8-HBondQuantityWorksheetContmunity&Econo;icDevelopmentUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016—RentonDatePrepared:7/25/2016jProjectPhaseIFORAPPROVALPreparedby:EngineerStampRequiredName:MaherA.JOUdi(allcastestimatesmusthaveoriginalwetstampandsignature)PERegistrationNo:45232FirmName:DR.STRONGConsultingEngineers,Inc.FirmAddress:6207thAvenuePhoneNo.425827.3063EmailAddress:maherjoudi@drstrong.comProjectLocationandDescriptionProjectOwnerInformationProjectName:VuecrestIIProjectOwner:HarbourHomes,LLCCEDPlanIt(LUA):LUA5-000026Phone:206.315.8130CEDPermit#(U):U15007232Address:400N34thStreet,Suite300SiteAddress:4903MainAveSSeattle,WA98103StreetIntersection:MainAveS&SE186thStAddt’IProjectOwner:N/AParcelli(s):3223059097Phone:AbbreviatedLegalN1/4OF5W1/4OFNW1/4OFSW1/4LESScoRDAddress:Description:ClearingandGradingUtilityProvidersClearingandgradinggreaterthanorequalto5,000boardfeetoftimber?Yes/No:INOIWaterServiceProvidedby:5005CREEKWATER&SEWERlfYes,ProvideForestPracticePermit#:IN/AISewerServiceProvidedby:CITYOFRENTONSECTIONIPROJECTINFORMATION CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFOREROSION&SEDIMENTCONTROLEROSION/SEDIMENTSUBTOTAL:44,436.80SALESTAX@9.5%F4,221.50IEROSION/SEDIMENTTOTAL:I48,65$J(A)UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016Unit(A)DescriptionNo.ReferenceUPriceUnitQuantityCostBackfi((&compaction-embankmentESC-16.50Checkdams,4’minusrockESC-2SWDM54.6.380.00Each11880.00CatchBasinProtectionESC-335.50Each14497.00Crushedsurfacing11/4mInusESC4WSDOTO-039(3)95.00CVDitchingESC-59.00CV79711.00Excavation-bulkESC-62.00CVFence,siltESC-7SWDM543.21.50LF664996.00Fence,Temporary(NGPE)ESC-81.50IFGeotextileFabricESC-92.50SVHayBaleSiltTrapESC-100.50EachHydroseedingESC41SWDM54.2.4080SV116669,332.80InterceptorSwaleIDikeESC421.00LFJuteMeshESC-13SWDM54.2.23.50SVLevelSpreaderESC441.75IFMulch,byhand,straw,3”deepESC-15SWDM54.2.1250SVMulch,bymachine,straw,2’deepESC-16SWDM5.4.2.12.00SV40008,000.00Piping,temporary,CPP,6”ESC-1712.00IFPiping,temporary,CPP,8”ESC-1814.00IFPipIng,temporary,CPP,12”ESC-1918.00IF25450.00Plasticcovering,6mmthick,sandbaggedESC-20SWDM5.42.34.00SY4171,668.00RipRap,machineplaced;slopesESC-21WSDOT9-31(2)4500CYRockConstructionEntrance,50’x15’xl’ESC-22SWDM5.4.4.131,800.00EachRockConstrudionEntrance,100’x15’xl’ESC-23SWDM5.4.4.13,20000Each13,200.00SedimentpondriserassemblyESC-24SWDM5.4.5.232,200.00EachSedimenttrap,5’highbermESC-25SWDM5.4.5.119.00IF1783,382.00Sed.trap,5’high,riprappedspiliwaybermsectionESC-26SWDM5.4.5J70.00LF6420.00Seeding,byhandESC-27SWDM5.4.2.4100SYSodding,1”deep,levelgroundESC-28SWDM5.4.2.58.00SYSodding,1”deep,slopedgroundESC-29SWDM54.2.51000SVTESCSupervisorESC-303110.00HR808,800.00Watertruck,dustcontrolESC-31SWOM5.4.714000HR405,600.00UnitWRITE-IN-ITEMSReference#PriceUnitQuantityCostSedimentTrapPump$50000Each1500.00Page3ofl4Ref8-HBondQuantityWorksheetSECTIONlI.aEROSION_CONTROl SITEIMPROVEMENTBONDQUANTITYWORKSHEET.FORSTREETANDSITEIMPROVEMENTSPage4of14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232ExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction)181CIID)ElDescriptionINo.UnitPriceUnitQuant.ICostQuant.ICostQuant.ICostDuanE.ICostCJTEMS‘mpaction-embankment-1$600CV2101,260.00ackflll&Compaction-trench-2$9.00CY64576.004083,672.00Brush,byhand(SY)-3$100SY-4240.74Each-removable-5452.34Each‘Grubbing/TreeRemoval-6$10,000.00Acre0377,700.001.5416,400.00on-bulk-7$2.00CY568211,364.00on-Trench-6$5.00CY64320.004082,040.00cedar,6’hIgh-92000LFchainlink,4’-1038.31LF37514,366.25chainlink,vinylcoated,6’high-112000LEchainlink,gate,vinylcoated,20’-12$1,400.00Eachmpact-commonbarrow-1325.00CYmpact-gravelbase-1427.00CVmpact-screenedtopsoil-1539.00CVn,12’deep,stonefilledmesh-1665.00SYn,16”deep,stonefilledmesh-1790.00SYn,36”deep,stonefilledmesh-ig15000SYng,fine,byhand-19$2.50SY“B’fine,withgrader-20$2.00SYments,3’Long-2125000Each1250.0041,000.00lyeAreasSign--$7.00Each535.00ng,1”deep,slopedground-23$8.00SYying,line&grade-2485000Day54,250.00eying,lotlocation/lines-25$1,800.00Acre1.642,952.00soilTypeA(imported)-2628.50CVticcontrolcrew(2flaggers)-2712000HR161,920.00,4”chippedwood-2$$$00SY,4”crushedcinder-29$900SY,4”topcourse-301200SYduit,2”-315.00LF,retaining,concrete-32$55.00SF$6647,630.00,rockery-33$15.00SFSUBTOTALTHISPAGE:r3,066.00II89,032.251123,637.00II(B)(C((D)(ElSECTIONll.bTRANSPORTATION UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSTREETANDSITEIMPROVEMENTSExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction)(B)(C)(Dl(ElDescriptionINo.UnitPriceUnitQuant.ICostQuant.ICostQuant.CostQuant.ICostPOADIMPROVEMENT/PAVEMENT/SURFACINACGrinding,4widemachine<l000sy-1$30.00SYCGrinding,4’wIdemachine1000-2000sy-2$16.00SYCGrinding,4’wIdemachine>2000sy-3$1000SYCRemoval/Disposal-4$35.00SYarricade,TypeIll(Permanent)-5$56.00IFuardRail-6$30.00IF2006,000.00urb&Gutter,rolled-717.00LFurb&Gutter,vertical-812.50IF1361,700.0086210,775.00urbandGutter,demolitionanddisposal-918.00IFurb,extrudedasphalt-105.50IFurb,extrudedconcrete-11$7.00IFwcut,asphalt,3”depth-121.85LF253468.05wcut,concrete,per1’depth-133.00IFalant,asphalt-14200IF253506.00houider,gravel.4”thick-15$15.00SYk,4”thick-16$38.00SY672,546.0028110,678.00k,4”thick,demolitionanddisposal-17$32.00SYk,5”thick484100SY712,911.00k,5”thick,demolitionanddisposal-194000SYndicap-2085.00Each,perstall-21700Each,thermoplastic,(forcrosswalk)-223.00SF,4”refiectorizedline-23$0.50IFnal2.5’CrushedSurfacing-24$3.60SY2”Overlay1.5”-2514.00SY2’Overlay2”-26$18.00SYad,2”,4’rock,First2500SY-2728.00SYad,2”,4”rock,Qty.over2500SY-2821.00SY-sad,4”,6’rock,First2500SY-294500SY2009,000.00162172,945.00ad,4”,6”rock,Qty.over2500SY-30$37.00SYsad,4”,4.5”ATB-3138.00SYRoad,4”rock,First2500SY-3215.00SYravelRoad,4”rock,Qty.over2500SY-3310.00SYhickenedEdge-..—8.60IFSUBTOTALTHISPAGE:t14,220.05IBII103,309.00IdID)lE)Page5ofl4Ref8-HBondQuantityWorksheetSECTIONii.bTRANSPORTATION SUBTOTALWRITE-INITEMS:STREETANDSITEIMPROVEMENTSSUBTOTAL:SALESTAX@9.5%STREETANDSITEIMPROVEMENTSTOTAL:IIIIUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSTREETANDSITEIMPROVEMENTSExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReductlon(181IC))D)ElINo.IUnitPriceUnitQuant.ICostQuant.ICostQuant.ICostQuant.ICostPARKINGI.OT‘No.2’AC,2topcourserock&4”borrowPL-1$21.00SY2AC,1.5*topcourse&2.5basecoursePL-2$28.00SY4”selectborrowPL-3$5.00SY1.5”topcourserock&2.5’basecoursePL-4$14.00SYSUBTOTALPARKINGLOTSURFACING:IIIIIIIIBIICIID))E)No.LA-i$200.00Each1200.0051,000.00MedianLandscapingLA-2Right-of-WayLandscapingLA-3$50.00SY1005,000.0024012,000.00WetlandLandscapingLA-4$17.25SY40690.00SUBTOTALLANDSCAPING&VEGETATION:I5,200.00II13,000.00II690.00118)ICIID)ElTRAFFIC&LI(No.SignsTR-1$200.00Each173,400.00StreetLightSystem(#ofPoles)TR-2$3,000.00Each824,000.00TrafficSignalTR-3TrafficSignalModificationTR-4SUBTOTALTRAFFIC&LIGHTING:III27,400.00IIB)IC)ID)lE)‘sI22,486.05II232,741.25II2,136.17II22,110.42II24,622.221I254,85167]IB)IC)!24,327.00II2,311.07II26,638.07IID)IIIIIIII)E)Page6of14Ref8-HBondQuantityWorksheetSECTION)).bTRANSPORTATION CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivateuantityRemainingRight-of-WayImprovementsImprovements(BondReduction((B)(C)D((F)DescriptionINo.UnitPriceUnitQuant.CostQuant.CostDRAINAGEcci’=CorrugatedPolyethylenePipe,NlzorEquivalent)ForCu)gggF4coverwasassurperforatedPVCiscessolidpipe.)AccessRoad,R/DD4$2600SY2406,240.00a(CBsincludeframeandlid)BeehiveD-290.00EachThrough-curbInletFrameworkD-3400.00Each1400.00CBTypeID-41,500.00Each23,000.0057,500.0034,500.00CBTypeILD-51,75000EachCBTypeII,48’diameterD-62,300.00Each24,600.0012,300.00foradditionaldepthover4’D-7480.00FTCBTypeII,54”diameterD-82,50000Eachforadditionaldepthover4’D-949500FTCBTypeII,60”diameterD-IO2,800.00Eachforadditionaldepthover4’D-11600.00FTCBTypeII,72’diameterD-126,000.00Eachforadditionaldepthover4’D43850.00FTCBTypeIl,96’diameterD4414,00000Eachforadditionaldepthover4’FTRack,12’EachRack,15”EachRack,18”EachRack,21”550.Eachout,PVC,4”150.0Eachout,PVC,6”170.0Each5850.00out,PVC,8”200.Eachrt,PVC,18”(NotallowedinROW)41.LFrt,CMP,B”D-3219.00LFI7,600.00j16,440.00111,785.00](BIIC)DlPage7ofl4Ref8-HBondOaantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016rt,PVC,6”IIrt,PVC,8”1rt,PVC,4”(NotallowedinROW)10.LFJotallowedirNotallowediirt,PVC,12”(NotallowedinROW)23.51,PVC,15”(NotallowedinROW)735.rt,PVC,24”(NotallowedinROW)rt,PVC,30”(NotallowedinROW)IFrt,PVC,36”(NotallowedinROW)IF29ROW)D13.IF4956,435.00nROW)15.IFrt,CMP,12”3O56.00IF3178.00LF130.00IF.332900IFSUBTOTAITHISPAGE:(ElSECTIONll.cDRAINAGE SITEiMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReductioni(B)(C)(D)fE)DescriptionINo.UnitPriceUnitQuantCostQuant.CostQuant.CostQuant.CostNAGE(Continued)CMP,15’D-3435.00LFCMP,18D-354100LFCMP,24”D-3656.00IFCMP,30’D-3778.00IFCMP,36D-38$130.00LF11CMP,4$D-39190.00LFrtCMP,60D40$270.00IFrtCMP,72”D-41$35000LFConcrete,8”D-424200IFConcrete,12D-434800IFConcrete,15”D-447800IFConcrete,18’D-454800IFConcrete,24”D-4678.00LFConcrete,30”D-47$125.00LFrt.CPE,12”(Nota(IowedinROW)D-5324.00IFrt,CPE,15”(NotallowedinROW)D-5435.00IFrt,CPE,18”(NotallowedinROW)D-5541.00IFVrt,CPE,24”(NotallowedinROW)D-5656.00IFVrt,CPE,30”(NotallowedinROW)D-5778.00IFrt,CPE,36”(NotallowedinROW)D-58$130.00IFrt,ICPE,6”D-5960.00IFrt,LCPE,8”D-6O72.00IFrt,ICPE,12”D-6184.00IF67056,280.00ri,LCPE,15”D-6296.00IFIII__56,28000I(B)(C)0)UnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232t,ICPE,18”63-64108.00IF-65120.00IF132.00IF144.00156.00IF168.00SUBTOTALTHISPAGE:Page8of14RefS-HBondQaantityWorksheetSECTION)(.cDRAINAGE IIII(0)tE)Page9of14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReductioni8)(C))D)(E)DescriptionINo.IUnitPriceIUnitQuant.ICostQuant.ICostQuant.ICostQuant.CostAtfu(vert.Iu(vert,LCPE,72(vert,HDPE,6-r42.00LFert,HDPE,8”-72$42.00LFerR,HDPE,12”-73$74.00LFHDPE,15--106.00LF,HDPE,18-75138.00LFHDPE,24-76221.00LF-77276.00LF331.00.Polypropytene.8,Potypropytene,36’,Potypropytene,48”,Potypropytene,54”‘Polypropytene,60’-8489.00LF,,____________________-85$95.00LF;“__ ________ ________ __-86100.00LFI’,____________________-87106.00LF,Potypropytene,24”-88111.00IF,Potypropytene,30”-89119.00LF-90154.00IF-91226.00IF-92332.00IF-93439.00IF-94545.00IF243.00IF-104266.00IF-105289.00IFSUBTOTALTH(SPAGE:-106311.00IFI19,504.00II(B)(C)SECT(ONt(.cDRAtNAGE LExistingFuturePubhcPrivateQiantityRemainingRight-of-WayImprovementsImprovements(BondReductioni18)IC))D))E)DescriptionINo.UnitPriceUnitQuant.CostQuant.CostQuant.CostQuant.CostinageItems————DitchingD-1$950CVFlowDispersalTrench(1,436base+(D-3$2800LFFrenchDrain(3depth)D-4$26.00LFGeotextile,(aidintrench,polypropyleneD-5$3_DoSYfl-6$2,00000EachI$SYIEachInfiltrationpondtestingb-13$12500HRPermeablePavementD-14PermeableConcreteSidewalkD-15Culvert,BoxftxftD-16SUBTOTALSPECIALTYDRAINAGEITEMS:—181(C)(D)fE)IsT0RMwATERFACILITIES(IncludeFlowntrnlandWaterQua“FaciPt’,SummaryStneitancCketch)IDetentionPondF-iEachIDetentionTankF-2EachIDetentionVaultF-3EachIInfiltrationPondF4EachIInfiltrationTankF-5EachI(nfiftrationVaultF-6EachI(nfi(trationTrenchesF-7Each[pcjofiftrationSwaleF-8EachWetBiofiltrationSwafeF-9EachWetpondF-iDEachWetvau)tF-liEachSandFilter•F-12EachSandFilterVaultF-13EachLinearSandFilterF-l4EachStormFilterF-15EachRainGardenF-16EachriIIIILIBI(C)(0)(E)Page10of14RefS-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESSUBTOTALSTORMWATERFACILITIES:SECTIONll.cDRAINAGE Pageflof14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORDRAINAGEANDSTORMWATERFACILITIESExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction)1eq5)(5)DescriptionINo.UnitPriceUnitQuant.jCostQuant.CostQuant.CostQuant.CostWRITE-IN-ITEMS-4-10-11-12-13-14-15[I[I-SUBTOTALWRITE-INITEMS:DRAINAGEANDSTORMWATERFACILITIESSUBTOTAL:SALESTAX@9.5%DRAINAGEANDSTORMWATERFACILITIESTOTAL:I1I7,600.oolI722.00II8,322.00IIBII72,720.00II6,908.40II79,628.40I(C)I11,78500I1,119.58II12,904.58I(Dl(6)SECTIONII.cDRAINAGE Page12of14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORWATERExistingFuturePublicPrivateQUantityRemainingRight-of-WayImprovementsImprovements(BondReduction((61(C)ID)fE)DescriptionNo.UnitPriceUnitQuant.CostQuant.CostQuant.CostQuarit.CostconnectiontoExistingWatermain-1$2,000.00EachDuctileIronWatermain,CL52,4InchDiameter-2$50.00LFDuctileIronWatermain,CL52,6InchDiameter-3$56.00LFDuctileIronWatermain,CL52,8InchDiameter-4$60.00LFDuctileIronWatermain,CL52,10InchDiameter-5$70.00LFDuctileIronWatermain,CL52,12InchDiameter-6$8000LFGateValve,4InchDiameter-7500.00EachGateValve,6inchDiameter-8700.00EachGateValve,6InchDiameter-9800.00EachGateValve,10InchDiameter-10$1,000.00EachGateValve,12InchDiameter-11$1,200.00EachFireHydrantAssembly-12$4,000.00EachPermanentBlow-OffAssembly-13$1,800.00EachAir-VacAssembly,2-InchDiameter-14$2,000.00EachAir-VacAssembly,1-InchDiameter-15$1,500.00EachCompoundMeterAssembly3-inchDiameter-16$8,000.00EachCompoundMeterAssembly4-inchDiameter-17$9,00000EachCompoundMeterAssemblyB-inchDiameter-18$10,000.00EachPressureReducingValveStation8-inchto10-inch-19$20,00000EachWATERSUBTOTAL:IIIIIIISALESTAX@9.5%IIIIIIIIWATERTOTAL:I1IIIIII181(ClIDI(ElSECTIONll.dWATER Page13of14Ref8-HBondQuantityWorksheetUnitPricesUpdated:06/14/2016Version:06/14/2016Printed8/26/2016CEDPermit#:U15007232SITEIMPROVEMENTBONDQUANTITYWORKSHEETFORSANITARYSEWERExistingFuturePublicPrivateQuantityRemainingRight-of-WayImprovementsImprovements(BondReduction)—tBlC)(0)IEIDescriptionNo.UnitPriceUnitQuant.CostQuant.CostQuant.CostQuant.CosteanOuts-1,000.00Each88,00O.0O.reaseInterceptor,500gallon-28,000.00EachreaseInterceptor,1000gallon-3$10,000.00EachreaseInterceptor,1500gallon-4$15,000.00EachewerPipe,PVC.4InchDiameter-5$$0.00LFewerPipe,PVC.6InchDiameter-6S95.00LF26925,555.00tPipe,PVC,8inchDiameter-7$105.00IF58060,900.00Pipe,PVC,12InchDiameter-8$120.00IFtPipe,Dl,8InchDiameter-9$115.00IFPipe,Dl,12InchDiameter-10$13000LFhnle,48InchDIameter-116,000.00Each424,000.00hole,54InchDiameter-136,500.00Eachhole,60InchDiameter-157,500.00Eachole,72InchDiameter-178,500.00Eachole,96InchDiameter-19$14,000.00EachPipe,C-900,12InchDiameter-21$180.00IFOutsideDrop-24$1,500.00ISnsideDrop-25$1,000.00ISSewerPipe,PVC,InchDiameter-26LiftStation(EntireSystem)-22TSANITARYSEWERSUBTOTAL:]84,900.00fI33,555.001IISALESTAX@9.5%II8,065.503,187.73IISANITARYSEWERTOTAL:III92,965.50II36,742.73III(B)(C))D)CE)SECTIONII.eSANITARYSEWER