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b. PostConstructionStormwaterManagementBMPsmustmeetthe <br />followingcriteria: <br />i. Designedwithacceptedengineeringpracticesandinaccordancewithpart3.d. <br />(PermanentStormwaterManagementSystemDesignCriteria). <br />ΝLƷĻƒЋЉ͵ЍΞ <br />ii. Designedsothatdischargesfromtheprojectduringandafterconstruction <br />activitiesdonotcauseaviolationofstatewaterqualitystandards,including <br />nuisanceconditions,erosioninreceivingchannelsorondownslope <br />properties,orasignificantadverseimpacttowetlandscausedbyinundation <br />ordecreaseofflow. <br />iii. Treatthewaterqualityvolumeonanyprojectwherethesumofthenewimpervious <br />surfaceandthefullyreconstructedimpervioussurfaceequalsoneormoreacres. <br />ΝLƷĻƒ <br />ЋЉ͵ЎΞ <br />iv. Forconstructionactivity(excludinglinearprojects),waterqualityvolumemustbe <br />calculatedasone(1)inchtimesthesumofthenewandthefullyreconstructed <br />impervioussurface.ΝLƷĻƒЋЉ͵ЏΞ <br />v. Forlinearprojects,waterqualityvolumemustbecalculatedasthelargerofone(1)inch <br />timesthenewimpervioussurfaceoronehalf(0.5)inchtimesthesumofthenewandthe <br />fullyreconstructedimpervioussurface.Wheretheentirewaterqualityvolumecannotbe <br />treatedwithintheexistingrightofway,areasonableattempttoobtainadditionalright <br />ofway,easement,orotherpermissiontotreatthestormwaterduringtheproject <br />planningprocessmustbemade.Volumereductionpracticesmustbeconsideredfirst,as <br />describedinSection3.b.vi.Volumereductionpracticesarenotrequiredifthepractices <br />cannotbe <br />providedcosteffectively.Ifadditionalrightofway,easements,orother <br />permissioncannotbeobtained,theowner/operatorofconstructionactivitymust <br />maximizethetreatmentofthewaterqualityvolumepriortodischargefrom theCityof <br />Centerville͸sMS4. <br />ΝLƷĻƒЋЉ͵АΞ <br />vi. Volumereductionpractices(e.g.,infiltrationorother)toretainthewaterqualityvolume <br />onsitemustbeconsideredfirstwhendesigningthepermanentstormwatertreatment <br />system.Wetsedimentationbasinsandfiltrationsystemsarenotconsideredvolume <br />reductionpractices.Ifinfiltrationisprohibited,asdescribedinPart3.d.i.14.(Infiltration <br />System),othervolumereductionpractices,awetsedimentationbasin,orafiltrationbasin <br />maybeconsidered.ΝLƷĻƒЋЉ͵БΞ <br />vii. Fordischargestoatroutstream,thesystemmustbedesignedsothedischargefromthe <br />projectminimizesanyincreaseinthetemperatureoftroutstreamsresultingfromtheone <br />(1)ortwo(2)year24hourprecipitationevents.Thisincludesalltributariesofdesignated <br />troutstreamslocatedwithinthesamePublicLandSurveySystem(PLSS)Section.The <br />designmustincorporateoneormoreofthefollowingmeasures,inorderofpreference: <br />1) Providestormwaterinfiltrationorothervolumereductionpracticesasdescribedin <br />Part3.b.iii.,3.b.iv.,and3.b.v.above,toreducerunoff.Infiltrationsystemsmust <br />dischargeallstormwaterroutedtothesystemwithin24hours; <br />2) ProvidestormwaterfiltrationasdescribedinPart3.d.ii.(FiltrationSystem).Filtration <br />systemsmustdischargeallstormwaterroutedtothesystemwithin24hours; <br />3) Minimizethedischargefromconnectedimpervioussurfacesbydischargingto <br />vegetatedareas,orgrassswales,andthroughtheuseofothernonstructuralcontrols; <br />March2024|wqstrm498 <br />Page 16 of 23 <br /> <br />