ImpingementMortalityDecisionTreeforBTATechnologyRequirementsEither1(1)installpreapprovedBTA(i.e.,modifiedtravellingscreenssuchasIfpreapprovedBTAistechnicallyinfeasibleDeMinimisException:Does( ,gRistroph screenswithpost‐Fletchermodificationsormaximumintakevelocity(i.e.,approachvelocity))andoperatesuchBTAtechnologyconsistentwithbestmanagementpracticesor(2)operatepreexistingoffshorevelocitycapsorclosedcyclecooling2consistentwithbestmanagementpracticesIfpreapprovedBTAistechnicallyinfeasiblebasedonsitespecificconsiderationsorifcompanydemonstratesthatmorecosteffectivetechnology(ies)willachievecomparableperformancetopreapprovedBTA,identifyBTAtechnology(ies),incoordinationwithpermittingdirector,throughfollowingsteps:thefacility’simpingementmortalitymeetoneofthedeminimisexceptions(e.g.,actualvs.designflow,numericimpingementlevel,oroperatingcharacteristics)?NoIfnotTechnologyOptions:IdentifypotentiallyavailabletechnologiesorOperateintakeconsistentwithbestmanagementYesmanagementpractices.SelectBTA(orcombinationoftechnologies)andinstallandoperateconsistentwithbestmanagementpracticesandmanufacturer’sp ygcombinationoftechnologies,consideringtechnologiesalreadyinstalled,thatminimizeimpingementmortality3:•Advancedscreenswithfishreturnsystems;practices.managementpracticesandmanufacturer srecommendations.Verifyeffectivenessduringrequiredpermittingreviewconsideringexpectedeffectivenessidentifiedinrankingprocess.•IntakeVelocity(i.e.,throughscreenvelocity);•Offshorevelocitycaps;•Diversiontechnology;•Wedgewire screens;or•OthertechnologiesbasedonsitespecificfactorsJustification:DocumentwhypreapprovedBTAtechnologiesareImpingementAnalysis:RankremainingtechnologiesbasedonCostBenefitAnalysiswithPermittingAuthority:Incoordinationwithpermittingdirector,evaluateremainingtechnologiesandidentifymosteffectivecontrolbasedoncostpreapprovedTAtechnologiesareinfeasibleatsiteandeliminateanyotherinfeasibletechnologies basedonsitespecificconsiderations.remainingtechnologiesbasedonexpectedimpingementmortalityreductionincludingavoidanceofimpingement.effectivecontrolbasedoncostbenefitanalysis4(e.g.,reductioninimpingementmortality,avoidedimpingement,andothersocialcostsandbenefits)anddocumentresults.ImpingementMortalityDecisionTreeforBTATechnologyRequirementsThisdecisionstructureprovidesalogicalandconsistentmechanismtomakeaBTAdeterminationforafacility.Withthepreapprovedoptionandobligationtooperatethattechnologyconsistentwithbestmanagementpractices,weanticipatethatthevastmajorityoffacilitieswillinstallthepreapprovedBTAtechnologyForthesmallsubsetoffacilitieswhereadvancedscreensor1. PreapprovedBTAincludemodifiedtravellingscreenssuchasRistroph screenswithpost‐Fletchermodificationsormaximumintakevelocity(i.e.,approachvelocity).Pre‐existingoffshorevelocitycapsorclosedcyclecooling(includingcoolingtowersvastmajorityoffacilitieswillinstallthepreapprovedBTAtechnology.Forthesmallsubsetoffacilitieswhereadvancedscreensorminimalintakevelocityisnottechnicallypractical,thisdecisionprocessensuresBTAisinstalledatthefacilitybasedon sitespecificconsiderations.NotesorcoolingpondsthatarenotdeterminedtobethewatersoftheU.S.)wouldbedeemedcompliantwiththeimpingementmortalitystandardsundersection316(b).Thus,unitsthathavepre‐existingoffshorevelocitycapsorclosedcyclecooling;haveorinstallmodifiedtravellingscreenssuchasRistroph screenswithpost‐Fletchermodifications;orthatmeetthemaximumintakevelocity(i.e.,approachvelocity)wouldberequiredtooperatethosetechnologiesconsistentwithbestmanagementpractices.2. Theproposeddefinitionofclosedcyclecoolingshouldberefinedtoeliminatetherequirementofaminimumnumberofcyclesofconcentration.3. InidentifyingallBTAtechnologies,thefacilityandpermittingdirectorshouldconsideranyapplicableexamplesincludedin adatabaseEPAestablishestoillustratetheexpectedperformanceofBTAtechnologiesatspecificsites.Theseexamplesshouldbebasedonarobustdatasetandreflectdifferentsituationsthatwillaffectimpingementsuchasdifferentwaterbodies,fragilespecies,facilitysizes,andseasonaldynamics.Theexpectedperformanceshouldbebasedonbothfishmortalityandbiomassandaccountforactionsthatpreventfishimpingement.Thisdatabasewouldfacilitatepermittingauthorities’identificationandassessmentofalternativestothepreapprovedBTAtechnologies.Theseexampleswouldnotestablishanationalstandardthato ldbeapplicabletofacilitiesnationalstandardwuapplicableallfacilities.4. CostBenefitAnalysisCriteria– Inthecostbenefitanalysis,thefacilityandpermittingdirectorshouldevaluatetheeconomicandenvironmentalimpactsassociatedwitheachoptionremainingunderconsideration.The“top”rankedtechnologyorcombinationoftechnologiesshouldbeconsideredBTAunlessthefacilitydemonstrates,andthepermittingdirectoragrees,th tthdi tli ttifl ith ltiblthaeeconomicanenvronmentalmpacsjusyaconcusonthathetecnoogyisnofeaseorecostsarenotjustifiedatthatfacility.Inthisevaluation,thefacilityandpermittingdirectorshouldconsidercomparableexamplesin thedatabasenotedabove,applicableliterature,andanyavailablesiteorcomparablesitestudies.Thiscostbenefitanalysiswouldbeconsistentwiththeanalysisforentrainment.