The URL can be used to link to this page

Home My WebLink AboutChelan Creek PUD Storm Adjustment ApprovalDenisLawCtf1YiCommunity&EconomicDevelopmentDepartmentC.E.”Chip”Vincent,AdministratorDecember17,2015Ms.CaraVisintainerCESNWInc.31029thStreetNE,Suite101Puyallup,WA98372RE:ChelanCreekPUD(U15005174)—AmericastFilterra®forResidentialandPublicUse-Adjustment2015-04DearMs.Visintainer:TheCityofRentonhascompletedreviewoftheadjustmentrequestfortheChelanCreekPUD(U15005174)inaccordancewithCityadopted2009KingCountySurfaceWaterDesignManualandassociatedCityAmendments.TheWashingtonStateDepartmentofEcologyhasapprovedtheFilterra®BioretentionSystemsforGeneralUseLevelDesignationforTotalSuspendedSolids,oilandgrease,andenhanceddissolvedmetalstreatment.Ourreviewoftheinformationleadsustounderstandthatyou,astheproject’sengineer,arerequestinganadjustmentfortheimplementationoftheFilterraSystemonresidentialpropertyownedbytheHomeownersAssociationandinpublicrightofway.TheAmericastFilterra®BioretentionSystemsforBasicTreatment,EnhancedBasicWaterQualityand/orOilTreatmentisapprovedwiththefollowingconditions:1.TheHomeowner’sAssociationisresponsibleforthemaintenanceandoperationoftheFilterra®Systemswithinprivateproperty(Filterra#1-perplans).2.TheHomeowner’sAssociationshallenterintoaservicecontractwithanapprovedcontractororFilterrarepresentativeforthelongtermmaintenanceofthesystemlocatedonprivatepropertytobemaintainedbytheHomeownersAssociation(Filterra#1)3.TheprojectdevelopershallalsoenterintoaserviceagreementwithFilterraSystemsand/orapprovedcontractorformaintenanceoftheFilterraSystemslocatedwithinCityright-of-way(Filterra#2andFilterra#3).Theserviceagreementshallencompassthetwoyearmaintenanceanddefectbondperiod.RentonCityHall1055SouthGradyWay.Renton,Washington98057rentonwa.gov Ms.CaraVistintainerPage2of3December17,2015Uponcompletionofthetwoyearmaintenanceanddefectperiod,theFilterrasystemsintheCity’spublicright-of-waywillbemaintainedbytheCity4.EachFilterra®unitshallbesizedforOilTreatmentusingafilterhydraulicconductivityof35.46inches/hour(assumingahydraulicgradientof1.41inch/inchaslistedintheWashingtonStateDepartmentofEcologyGeneralUseLevelDesignationforAmericast’sFilterra®)usingthesandfiltermoduleinthelatestversionoftheWesternWashingtonHydrologyModel(WWHM)orotherEcology-approvedcontinuousrunoffmodel.Themodelmustindicatetheunitiscapableofprocessing91percentoftheinfluentrunofffile.5.EachFilterra®unitshallbesizedforBasicTreatmentusingafilterhydraulicconductivityof35.46inches/hour(assumingahydraulicgradientof1.41inch/inchaslistedintheTechnicalInformationReport(TIR))usingthesandfiltermoduleinthelatestversionoftheWesternWashingtonHydrologyModelorotherEcology-approvedcontinuousrunoffmodel.Themodelmustindicatetheunitiscapableofprocessing91percentoftheinfluentrunofffile.6.Filterra®mediashallconformtothespecificationssubmittedtoandapprovedbyEcology.7.Facilityinspection,maintenance,andreportingarerequiredbytheCityofRentonSurfaceWaterUtilityfortheHomeownerAssociationmaintainedFilterra(Filterra#1)inperpetuity.TheFilterra’s(Filterra#2andFilterra#3)constructedinpublicright-of-waymustbeinspected,maintainedandreportsprovidedtotheSurfaceWaterUtilitybytheHomeownersassociationduringthe2-yearmaintenanceanddefectbondperiod.Thefacilityinspection,maintenanceandreportingisrequiredpertheEcologyNationalPollutantDischargeEliminationSystemPhaseIIMunicipalStormwaterPermit(SectionS5.C.4.c.iii).Facilityownersareresponsibleforensuringthatstormwaterfacilitiesareproperlymaintainedandfunctioningasdesignedandpermitted.TheFilterra®facilityshallbeinspectedeverysixmonthsbythesupplierduringthefirstyearofoperationasofferedwiththepurchaseoftheFilterra®systems.Inspectionswillbeusedtodeterminethesite-specificmaintenanceschedulesandrequirements.Maintenanceofthefacilityshallincluderemovingtrash,degradedmulch,replacementofdiseased,damagedordeadtreesandaccumulateddebrisfromthefiltersurfaceandreplacingthemulchlayer.MaintenanceproceduresshouldfollowthosegiveninthemostrecentversionoftheFilterra®BioretentionSystemsOperationandMaintenanceManual.Duringthefirstyearofoperationofthefacility,writtenrecordsoftheinspectionsandmaintenanceshallbesubmittedtotheCityofRentonSurfaceWaterUtilityPrivateStormwaterInspectionProgram. Ms.CaraVistintainerPage3of3December17,20158.Followingthefirstyearofoperation,theHomeowner’sAssociationand/orrepresentativeofthefacilityshallannuallyhavetheFilterra®BioretentionSystemsinspectedandmaintainedpertheproceduresinthemostrecentversionoftheFilterra®BioretentionSystemsOperationandMaintenanceManual.WrittenrecordsoftheinspectionandmaintenanceshallbesubmittedtotheCityofRentonSurfaceWaterUtility,totheattentionofSurfaceWaterUtilityPrivateStormwaterFacilityInspectionProgram.IfmorefrequentinspectionandmaintenanceoftheFilterra®BioretentionSystemsisrequiredbythemanufacturerorisneededtoensureperformanceofthefacility,thentheadditionalinspectionandmaintenancereportscompletedwithintheyearshallbeprovidedwiththeannualreport.9.TheapplicantwillneedtosubmitaDrainageFacilityCovenantforinspectionandmaintenanceoftheprivateFilterra®treatmentfacilitythatwillbeprivatelymaintained.TheDrainageFacilityCovenantcanbefoundinReferenceJoftheCityofRentonAmendmentstothe2009KingCountySurfaceWaterDesignManual.AsiteplanshowingthelocationofthetreatmentfacilitymustbeincludedasExhibitAwiththedeclarationofcovenant.10.Theapprovalofthisadjustmentdoesnotrelievetheapplicantfromothercity,state,orfederalrequirements.Ifyouhaveanyquestionsaboutthisadjustment,pleasecontactRonStraka,SurfaceWaterUtilityEngineeringManager,at(425)430-7248.Sincerely/BnanneBannwah,P.E.RonStraka,P.E.DevelopmentEngineeringManagerSurfaceWaterUtilityEngineeringManagercc:LysHornsby,P.E.,UtilitySystemsDirectorMikeStenhouse,MaintenanceServicesDirectorJanlIlian,PlanReviewerRocaleTimmons,PlannerHebéBernardo,SurfaceWaterUtilityEngineer\\RvFPS-02\Depts\PW\FileSys\SWP-SurfaceWaterProjects\SWP-27-SurfaceWaterProjects(CIP)\27-3129RentonStormwaterManual\ADJUSTMENTS\2015\2015-4ChelanCreekPUD-Residential-PublicFilterra.doc\HCBah