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Home My WebLink AboutSUS411']11]JJ]]]]]]]]1]1,....SUSITNAHYDROELECTRICPRoJtCTi.FIRSTINTERIMM1TIGATIONPLANFORCHUMSALMONSPAWNING•HABITATINSIDESLOUGHSOFTHEMIDDLESUSITNARIVERPREPAREDBY:WOODWARD-CLYDECONSULTANTS701SESAMESTREETANCHORAGE,ALASKA99503SUBMITTEDTO:HARZA-EBASCOSUSITNAJOINTVENTURE711HSTREETANCHORAGE,ALASKA99501FOR:THEALASKAPOWERAUTHORITY324W.5THAVENUE,2NDFLOORANCHORAGE,ALASKA99501NOVEMBER1984Dill.FT TABLEOFCONTENTS1 -INTRODUCTION1.1-ApproachtoMitigation1.2 -Scope1.3-SelectionofEvaluationSpecies1.4-OverviewofSelectedEvaluationSpeciesintheMiddleSusitnaRiver2 -MITIGATIONOPTIONS-HISTORICALPERSPECTIVE2.1~FlowRelease2.2-HabitatModification2.2.1-Alaska2.2.2-CanadianChumEnhancementProjects2.2.3-WashingtonState'.Page11236999913143 -SUSITNARIVERMITIGATIONPLAN243.1-ImpactAssessment243.1.1SpawningHabitatUtilizationinSloughsandSideChannels243.1.2ProjectRelatedPhysicalChangesinSloughsandSideChannels263.1.3RelationshipBetweenPhysicalChangesandAvailableHabitatinSloughsandSideChannels293.2-MitigationOptions353.2.1FlowRelease353.2.2HabitatModification423.2.3ArtificialPropagation763.3-MonitoringStudies3.3.1ImpactMonitoringofSalmonPopulations3.3.2MitigationMonitoring4 -REFERENCESAPPENDIXAPassageReachFlowEvaluationAPPENDIXBDetailedMitigationCosts818182 LISTOFTABLESTable1.SusitnaRiverannualsalmonescapementbysub-basinandspeciesTable2.ChumsalmonpeakindexcountsbyhabitattypeaboveRM98.6,,1981-1983.Table3.ChumsalmonpeakindexcountsinsloughsaboveRM98.6,1981-1983.Table4.Second-runsockeyesalmonpeaksurveycountsinsloughsaboveRM98.6,1981-1983Table5.Pinksalmontotalsloughescapement1981-1983.aboveRM98.6,Table6.Selectedriverswithhydroelectricprojectsandassociatedmitigationsforanadromousfishspecies.Table7.Table8.Table9.AreaspawnedwithinSlough8Abackwaterbetweenpassagereachesfor1982,1983andofthecompositetothetotalareaspawnedalsoshown.AreaspawnedwithinSlough9backwaterbetweenpassagereachesfor1982,1983andofthecompositetothetotalareaspawnedalsoshown.AreaspawnedwithinSlough9Abackwaterbetweenpassagereachesfor1982,1983andofthecompositetothetotalareaspawnedalsoshown.zoneandareas1984.Theratioforallyearsiszoneandareas1984.Theratioforallyearsiszoneandareas1984.TheratioforallyearsisTable10.AreaspawnedwithinSlough11backwaterzoneandareasbetweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.Table11.AreaspawnedbetweenpassagereacheswithinSideChannel21betweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.Table12.AreaspawnedbetweenpassagereacheswithinSlough21betweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspa~~edforall,yearsisalsoshown. LISTOFTABLES(Continued)Table13.AreaspawnedwithinSideChannel21backwaterzoneandareasbetweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.Table14.MeanmonthlydischargesatGoldCreekfornaturalconditions.Table15.Relationshipbetweenmitigationalternativesandtheimpactsforwhichtheyareapplicable.Table16.Summaryofestimatedcostsforhabitatmodificationmeasuresinselectedsloughsandsidechannels.Table17.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduring'theperiod20August-20SeptemberatSlough8A.Table18.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough9.Table19.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough9A.Table20.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough11.Table21.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatUpperSideChannel11.Table22.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough21.Table23.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSideChannel21.Table24.Candidagesitesfordevelopmentofreplacementspawninghabitat. LISTOFFIGURES1981-1983Susitnachumescapementandrelativeutilization1981-1983SusitnacohoescapementandrelativeutilizationOdd-year(1981and1983)Susitnapinkescapementandrelativeutilization.PredictedwintermainstemstagesfornaturalandprojectflowsneartheheadofSlough8AbetweenrelativerelativeandandescapementsockeyechinookescapementShoreicebuildupwithoutovertoppingSchematicdiagramillustratingdifferencecompositeareaandtotalareaspawned1981-1983Susitnautilization.1982-1983SusitnautilizationFigure1.Figure2.Figure3.Figure4.Figure5.Figure6.Figure7.Figure8.Figure9.PredictedwintermainstemstagesfornaturalandprojectflowsneartheheadofSlough9Figure10.PredictedwintermainstemstagesfornaturalandprojectflowsneartheheadofSlough9AFigure11.PredictedwintermainstemstagesfornaturalandproejctflowsneartheheadofSlough11Figure12.PredictedwintermainstemstagesfornaturalandprojectflowsneartheheadofSlough21Figure13.Simulatedminimum,maximumandmeanmonthlydischargesformaximumpowerCaseP-1comparedwithminimum,maximumandmeanmonthlydischargesfornaturalconditionsFigure14.MinimumandmaximumweeklydischargesforCaseCflowscomparedwithminimum,maximumandmeanmonthlydischargesfornaturalconditionsFigure15.MinimumandmaximumweeklydischargesforCaseEVflowscomparedwithminimum,maximumandmeanmonthlydischargesfornaturalconditionsFigure16.MinimumandmaximumweeklydischargesforCaseEVIflowscomparedwithminimum,maximumandmeanmonthlydischargesfornaturalconditions. ~~~-.-.-.J"'~~1..JJ-.JLISTOFFIGURES(Continued)Figure17.·Simulatedminimum,maximumandmeanmonthlydischargescomparedwithminimumandmaximumweeklydischargesforCaseEVIinstreamflowrequirementsFigure18.WingdeflectorFigure19.TypicalpassagereachofsloughalongmiddlesectionoftheSusitnaRiverFigure20.RockgabionchannelFigure21.ChannelbarriersFigure22.CollectortankatSlough9Figure23.ThalwegprofileofSlough9Figure24.ThalwegprofileofSlough11Figure25.ThalwegprofileofSlough21Figure26.InducedupwellingusingtributarywatersupplyFigure27•WeirtoincreasespawninghabitatFigure28.TimberpostweirFigure29.RockgabionweirFigure30.RockweirFigure31.Bermdesigntopreventovertoppingofsloughs-.~..J~..J.J-"Figure32.Figure33.Figure34.Figure35.Figure36.LocationsofmitigationmeasuresdistributionsofspawningchumsalmonSlough8ALocationsofmitigationmeasuresdistributionsofspawningchumsalmonSlough9LocationsofmitigationmeasuresdistributionsofspawningchumsalmonSlough9ALocationsofmitigationmeasuresdistributionsofspawningchumsalmonSlough11andUpperSideChannel11LocationsofmitigationmeasuresdistributionsofspawningchumsalmonLowerSideChannel21.andpercentageduring1984inandpercentageduring1984inandpercentageduring1984inandpercentageduring1984inandpercentageduring1984in l_~J[[[[[[[[[[[[~":,[[[[[r"u1 -INTRODUCTION1.1-ApproachtoMitigationTheAlaskaPowerAuthority's(APA)goalforSusitnaHydroelectricProjectfisheriesmitigationistomaintaintheproductivityofnaturalreproducingpopulations(AcresAmerican1983).ThisisconsistentwiththemitigationgoalsoftheU.S•.FishandWildlifeService(USFWS)andtheAlaskaDepartmentofFishandGame(ADF&G)(APA1982,ADF&G1982a,USFWS1981).TheAPAplanstoeithermaintainexistinghabitatorprovidereplacementhabitatofsufficientquantityandqualitytomaintainthisproductivity.Whereitisnotfeasibletoachievethis,goal,APAwillcompensatefortheimpactwithpropagationfacilities.MitigationmeasuresproposedfortheSusitnaHydroelectricProjectaregroupedinto~wobroadapproaches:Modificationstodesign,construction,oroperationoftheprojectResourcemanagementstrategiesThefirstapproachisprojectspecificandemphasizesthef~~a~~~m~m~m~~~~~0~~~jp~~af~n~~Grf~adur~~i~~f~adverseimpactsaccordingtotheFishandWildlifeMitigationPolicyestablishedbytheAPA(1982)andcoordinatingagencies(ADF&G1982a,USFWS'1981).Thesemeasuresinvolveadjustingoraddingprojectfeaturesduringdesignandplanningsothatmitigationbecomesabuilt-incomponentofprojectactions.Ifimpactscannotbemitigatedbythefirstapproach,t;'\,<;j.JJ!~~i.rc£n'!jll!)~·C::CilJ):J.'f>";"~~~~"1,~~~.measureswillbeimplemented.Thistypeofmitigationwillinvolvemanagementoftheresourceratherthanadjustmentstotheproject,andwillrequireconcurrenceofresourcemanagementboardsoragencieswithjurisdictionoverresourceswithintheprojectarea.1 -",.,~,-''-'l!.."--"1_J~J-.,-",JlJJJ.....--MitigationplanningfortheSusitnaHydroelectricProjecthasemphasizedbothapproaches.Thesequenceofoptionsfromavoidancethroughcompensationhasbeenappliedtoeachimpactissue.Iffullmitigationcanbeachievedatahighpriorityoption,loweroptionsmaynotbeconsidered.Intheresultingmitigationplans,measurestoavoid,minimize,orrectifypotentialimpactsaretreatedingreatestdetail.Specificationsforfacilitysitinganddesign,specialmitigationfacilities,constructionprocedures,andschedulingofprojectactionstomitigateadverseeffectsonthebiotaarepresented.Monitoringandmaintenanceofmitigationfeaturestoreduceimpactsovertimearerecognizedasintegralpartsofthemitigationprocess.Themonitoringprogramwillbedevelopedduringdetailedengineeringdesignandconstructionplanningandbeappliedtofisheryresourcesandtheirhabitat.1.2 -ScopeThisreportspecificallyaddressesplanstomitigateimpactsonchumsalmonspawninghabitatintheTalkeetnatoDevilCanyonreachoftheSusitnaRiver(middleSusitnaRiver).Theplansarepresentedforselectedsloughs;however,theyareapplicabletoothersloughsinthemiddleSusitnaRiver,wherephysicalimpactsareexpectedtobesimilar.Thesloughsselectedfordetailedanalysisinthisreportarethesloughsmostheavilyutilizedbyspawningsalmonduringthe1981-1984studyperiod.Themitigationplansforotherspecies/lifestages(e.g.chinookrearing),otherprojectareas(e.g.impoundment),andtheapplicabilityofproposedmitigationplanstootherphasesoftheproject(e.g.Watanafilling)aresubjectsofupcomingreports.~S~1'Ae;'Dot;t."",n;l'\es·en:tt(Si'i~a:llit~e!t.na~.;,:nWe~'I')lnOld,e;c:t~;ffJraw~~\¥a"'ifm:e}s;?§xasBiflthe1i'd"p',zvima;F,y';·...~·;~~~lTi~;.~~.t;;';.~;;~-_..···-..,'---'--"--_'r$:''''l"~;J~.~-...--"··........;..-b-'.---'-·-···----,(·'--;·;;',:;;:i...:::'~,_,::~,~,;f.:i:;:,,_'~1i·;~iii'~',~<'~"""-"'~'~"'""-__""'''''~'if''''_<;~'_'''"~~.~,,,,'"i·~'l;"""""'li-~~ii'.!I~~~.mr~~f'ive'W~trematWive'''''fo9r'~eR'fn()''"aK'''Juvenl::reari"d~p~rt'"'f1fI1ii±t·J:gaffOn~"'~r(:j':re~u~~s~~wn~ng.Additionalchumsalmonspawningmitigationfollowsone•~_'·"~,_.-....C~.,.•_,.:,;',-_',.o.:,,,,,,.._..~ofthefollowingstrategies:(1)structuralmodificationtopresentlyutilizedsidesloughstomaintainsemi-naturalspawningand2 ~..".~-,-."-,~-"""?~-i"J"--"J-"...J(2)artificialpropagationwithstream-sideeggboxestocompensateforlosses.AsstatedintheLicenseApplication(AcresAmerican1983),fullmitigationcanbeachievedwitheitherstrategy.Finaldecisionsonthestrategytobeimplementedwillbemadethroughdiscussionswithresourcemanagers.1.3-SelectionofEvaluationSpeciesAllthreemitigationpolicies(APA,ADF&GandUSFWS)implythatprojectimpactsonthehabitatsofcertainsensitivefishspecieswillbeofgreaterconcernthanchangesindistributionandabundanceoflesssensitivespecies.Sensitivitycanberelatedtohighhumanusevalueaswellassusceptibilitytochangebecauseofprojectimpacts.Statewidepoliciesandmanagementapproachesofresourceagenciessuggestthatconcernforfishandwildlifespecieswithconunercial,subsistence,andotherconsumptiveusesisgreaterthanforspecieswithoutsuchvalue.Thesespeciesareoftennumerous,andutilizeawiderangeofhabitats,aswellashavinghighhumanusevalue.Suchcharacteristicsoftenresultinthesespeciesbeingselectedforcarefulevaluationwhentheirhabitatsaresubjectedtoalternativeuses.Byavoidingorminimizingalterationstohabitatsutilizedbytheseevaluationspecies,theimpactstootherlesssensitivespeciesthatutilizesimilarhabitatscanalsobeavoidedorreduced.Theevaluationspecieswereselectedafterinitialbaselinestudiesandimpactassessmentshadidentifiedthedominantspeicesandpotentialimpactsonavailablehabitatsthroughouttheyear.Mitigationswerethendevelopedthatwillreduceimpactsonhabitatparametersthatareexpectedtocontrolpopulations•Specieswithhighregionalvisibilityandcommercial,sport,.Jsubsistence,oraestheticvalueweregivenpriority.Withinthiscategory,speciessensitivetoprojecteffectswerehighlyrated.Sincetheevaluationspeciesplayadominantroleinthe"'"-"ecosystem,theymayserveasindicatorspeices.3Bymaintaining criticalhabitatsforevaluationspecies,impactsonlesssensitivespeciesorevaluationprioritymaybemitigated.manyofthespecieswithpotentialalowerBasedontheaquaticstudiesbaselinereports,impactassessments,andharvestcontributions,fivespeciesofPacificsalmon(chum,sockeye,chinook,coho,andpink)wereidentifiedasevaluationspeciesfortheSusitnaRiverdownstreamfromDevilCanyon.SockeyesalmonwerenotincludedinExhibitEasanevaluationspeciessince,atthattime,theywereconsideredstraysoftheChulitnaRiverstock.However,recentevidenceindicatesthatsockeyeinthemiddleSusitnaRivermaybeaviablestock(DanaSchmidt,ADF&G,pers.comm.,1984).SincethegreatestchangesindownstreamhabitatsareexpectedinthereachbetweenDevilCanyonandTalkeetna,fishusingthatportionoftheriverwereconsideredtobethemostsensitivetoprojecteffects~Becauseofdifferencesintheirseasonalhabitatrequirements,notallsalmonspecieswouldbeequallyaffectedbytheproposedproject.Ofthefivespecies,chumandsockeyesalmonappeartobethemostvulnerableinthisreach,becauseoftheirdependenceonslough/.;habitatsforspawning,.incubationandearlyrearing.Ofthesetwo,..;chumsalmonarethedominantspecies.Chinookandcohosalmonarelesslikelytobeimpactedbytheprojectbecausetwocriticallifestages,spawningandincubation,occurinhabitatsthatarenotlikelytobealteredbytheproject.WhilesomepinksalmonspawninsloughhabitatsinthereachbetweenDevilCanyonandTalkeetna,mostofthesefishutilizetributaryhabitats.Themitigationsproposedtomaintainchumsalmonproductivityshouldallowsockeyeandpinksalmontobemaintainedaswell.Thechinookandcohosalmonjuvenilesrearintheriverforonetotwoyearspriortoout-migration.Muchofthecohorearingapparentlyoccursinclearwater.areas,suchasinsloughsandtributarymouths,withchinook.rearinginturbidsidechannelsaswellasclearwaterareas.Improvedconditionsinthemainstemareexpectedtoprovidereplacementhabitattomitigateforthepotentiallossofrearingareasinsloughhabitats.Juvenileoverwinteringhabitatsarenotexpectedtobeadverselyaffected.4 --'I-,."'"1_3--'I~,---'~~...."...."~'1---:-"....-JI.,.-J.JInsummary,theevaluationspeciesandlifestagesselectedfortheSusitnaHydroelectricProjectintheDevilCanyontoCookInletReachare:ChumSalmonSpawningadults;Embryosandpre-emergentfry;Emergentfry;Returningadults;andOut-migrantjuvenilesSockeyeSalmonSpawningadults;Embryosandpre-emergentfry;Emergentfry;Returningadults;andOut-migrantjuveniles.ChinookSalmonRearingjuveniles;andReturningadults.CohoSalmonRearingjuveniles;andReturningadults.PinkSalmonSpawningadults;andEmbryosandpre-emergentfry;Emergentfry;Returningadults;andOut-migrantjuveniles•5 -~.__J"----.J-~_,J"!!•....J~oJ"'~.J'"d..~=-"!.J'1J"'1J--.~~--..JJJJJ.J1.4-OverviewofSelectedEvaluationSpeciesintheMiddleSusitnaRiverFisheryresourcesintheSusitnaRivercomprisea.majorportionoftheCookInletcommercialsalmonharvestandprovidesportfishingforresidentsofAnchorageandthesurr,oundingarea.TheTalkeetna-DevilCanyonsub-basinprovides~~forannualescapementsofapproximately24,100chum;8,500chinook;2,200coho;54,800even-yearpink;4,400odd-yearpink;and2,800sockeye(Table1).Oftheannual-:escapementtotheSusitnaRiver-'Basin,thesub-basinescapementsareabout7percenteachforchumand'chinook,3percentforcoho,'4percentforeven-yearpink,3percentforodd-yearpinkand1percentforsockeye•Figures1to5showannualsalmonescapementstotheTalkeetna-DevilCanyonsub-basinandrelativeutilizationofslough,tributariesandmainstemareas•r€{'MostchumsalmonaboveRM98.6spawnineithersloughS'ortributartstr&amhaeitars(ADF&G1981,1983a,1984a).About93percentofthe10,570ch~msalmoncountedduringpeakindexsurveyswereobservedintributarl~~rsloughJhJilijta~theremaining7percentwereobservedatmainstemspawningsites(Table2).In1983,chumsalmonpeakindexieJ'countsintributartandsloughSI_fEats.,wereaboutequal,whilein1982and1981,countswerehigherinslough~~(Table2).Chumsalmonpeakindexcountsin.middleSusitnaRiversloughsarepresentedinTable3.Elevenofthe33sloughssurveyedinallthreeyearssupportedchumsalmonspawningineachyear.Fouroftheeleven,Sloughs8A,9,11and21,averagedover200fishannuallyforthethreeyearsandaccountedforabouttwo-thirdsofthetotalchumsalmoncountedinslough~ha~bats.ChumsalmonpeakcountsatmainstemspawningsitesarepresentedinTable2.Eighteenchumsalmonmainstemspawningsiteswereidentifiedduring1981-1983surveys;sevensiteswereused,intwoormoreofthethreeyears(Table3).6 mainchannelsite(RM138.6-138.9)spawningsitewasidentifiedduringthe1981-1983surveys(ADF&G1981,1983,1984).Sixsecond-runsockeyewereobservedintributariesduringthe1981-1983surveys.ThepeakofchumsalmonspawningoccurredduringthelastweekofAugustintributaries,thefirstweekofSeptemberinsloughs,andthefirsttwoweeksofSeptemberatmainstemspawningsitesinallthreeyears(ADF&G1981,1983a,1984a).jSockeyesalmonescapementstotheSusitnaRiversystemconsistoftwodistinctruns.Thefirst-runsockeyespawnexclusivelyintheTalkeetnaRiverdrainage.Second-runsockeyearedistributedsystem-wide.Mostsecond-runsockeyesalmonintheTalkeetna-DevilCanyonsub-basinspawninsloughhabitat(ADF&G1981,1983a,1984a).Approximately99percentofthe2,420second-runsockeyecountedduringpeakspawnercountswereobservedinsloughs.Theremainingsecond-runsockeyesalmonwereinthemainstemandtributaries;One\/'-Allsix,however,wereconsideredmillingfishthatdidnotspawn~n~:Vstreams(ADF&G1981,1983,1984).Duringsp~~surveys~n1981-1983,second-runsockeyewereobservedinITsloughs'-above_RM98.6(Table4).Only3ofthe17sloughscontainedsignifi~ant.l-numbersofspawningsecond~runsockeyeinallthreey~ars.\SloughsBA,11and21accountedfor89percentofthe._totalslol,lghpeakcountsin1981,95percentin1982and92percent_in198:3(Table4).ThepeakofspawningoccurredbetweenthelastweekofAugustandtheendofSeptemberinallthreeyears(ADF&G1984a).MostcohosalmonintheTalkeetna-DevilCanyonsub-basinspawnedintributaries.Duringspawninggroundpeaksurveysin1981-1983,over99percentofthe1,336cohosalmoncountedwereobservedintributaries.Onlyfivecohosalmonwereobservedspawninginmainstemandsloughhabitats(ADF&G1983a).MostpinksalmonintheTalkeetna-DevilCanyonsub-basinspawnintributaries(ADF&G1984a).Pinksalmonweredocumentedspawninginsloughsin1981and1982(ADF&G1981,1983a).TotalsloughescapementofpinksalmonaboveRM98.6in1981was38fishinSlough87 ".,-.-.~'"-"~,J~J-'""J~J'1....".1"--~.JI~(Table5).In1982,totalpinksalmonescapementaboveRM98.6wasabout297fishinsevensloughs(Table5).Twoofthesevensloughs,11and20,accountedforover80percentofthepinksalmontotalescapementinsloughsin1982.Nopinksalmonwereobservedspawninginsloughsin1983;fishcountedinsloughhabitatduringspawningsurveysin1983wereconsideredmillingfish(ADF&G1984a).In1981,thepeakofpinksalmonspawninginSlough8occurredaboutthelastweekofAugust,whilein1982thepeakofpinksalmonspawninginsloughsoccurredduringthefirstthreeweeksofAugust(ADF&G1984a).NopinksalmonwereobservedspawninginthemainstemoftheSusitnaRiveraboveRM98.6in1981-1983(ADF&G1984a).ChinooksalmonspawnexclusivelyintributarystreamhabitataboveRM98.6(ADF&G1984a).Nochinookspawninghasbeenobservedinanymainstem,sidechannelorsloughhabitats.8/" ~--3,---.JJ"~,"-11~'I~.-JJ-.,-"-."-"1-iI-"--."c..ll--,--IiJJJd2 -MITIGATIONOPTIONS-HISTORICALPERSPECTIVE2.1-FlowReleaseFlowreleasesdesignedtomeetinstreamflowrequirementsoffisheryresourcesaremitigativemeasuresthathaverecentlybeenroutinelyincorporatedinprojectoperations.Historically,thiswasnotalwaysthecase.Asolderprojectsarerelicensed,flow-releaserestrictionsarebeinginstitutedtoprotectdownstreamfishhabitat.Instreamflowrequirementsforanadromousspecieshavegenerallyfocusedonthespawningandincubationlifestagesasflowneedsfortheselifestagesaremoreeasilyassessedthanforotherstages.Minimalandtargetmaximumflowsareoftenrequiredduringthespawningseasonwhileminimumflowsbasedonthespawningflowareimplementedduringtheperiodsofincubationandemergence.Recently,'rampingrateandamplituderestrictionshavebeenplacedintheflowreleaseschedulesofseveralprojectstoavoidstrandingoffryandjuvenilesduringflowfluctuations.Aselectionofriverswithanadromousfishpopulationsandhydroelectricorfloodcontrolprojectsandassociatedmitigationmeasures,includingflowreleaserestrictions,ispresentedinTable6.2.2-HabitatModificationOn-sitehabitatmodificationasamitigationoptionforhydroe~ectricprojectshasrarelybeenemployed.Habitatmodificationsasenhancementprojectsaremorecommonplace,andthevarioustechniquesemployedareapplicabletothesloughandsidechannelareasoftheSusitnaRiver.Examplesofmitigationand/orenhancementprojectsinAlaska,BritishColumbiaandWashingtonStatearepresentedbelow.2.2.1-Alaska(a)ChilkatRiverSalmonEnhancementProjectIn1983,theNorthernSoutheastRegionalAquacultureAssociation(NSRAA)completedconstructionofa1S00-foot9 '-------...;-~U''-"LJr~!~L.rL.wcJspawningchannelforchumsalmonnearHaines,Alaska(Bachen1984).ThechannelwaslocatedinthefloodplainoftheKlehiniRiverabovetheconfluencewiththeChilkatRiver.Theexistingchannelhadsupportedchumspawninginpreviousyears.Intheconstructionprocessnativematerialwasexcavatedfromthechannelandsortedonsite;particlesinthesizerangeof3/4to3inchwerereturnedtothechannel.Flowthroughthechannelwassuppliedby6-7°Cgroundwateratarateofapproximately2.7-5.6cfs.Thechannelwasdividedintothreelevelsectionswithsix-inchdropsbetweensections.Woodencheckdamsplacedatthelowerendofeachsectionprovided.adequatedepthforspawningupstream.Duringthefirstyearofoperation,461chumsalmonand117cohosalmonreturnedtothechannel.Approximately700chum·salmonhadusedthechannelinpreviousyears.Thelowerthanaverageutilizationmaybeattr:i,butedtotheweakescapementin1983.However,theestimatedegg-to-frysurvivalthefollowingspringwas22-24·percent,substantiallygreaterthanthesurvivalintheunimprovedsystem.Inthesecondyearofoperation,approximately1500fishhadreturnedtothechannelbytheendofOctober.Thechannelwasdesignedtoaccommodateasmanyas3000femalesassuminguniformdistributionoffishatadensityofonefemale/IIsquarefeet.Thechannelwasconstructedatacostof$125,000orapproximately$37persquareyard.Theonlyscheduledmaintenanceforthechannelisweeklyremovalofcarcassesduringthespawningseasontopreventincreasedoxygendemandresultingfromdecomposition.10. ~"~-'l-J-~"~-',......Jj--"~~JApplicationtoSusitnaRiverMitigationPlan.Althoughtheprojecthasonlybeeninoperationfor2years,chumsalmonescapementinthesecondyearwasatleast1500fish,overtwiceitshistoricaluse.~fegg-to-frysurvivalrateof22-24percent(about2-3timestheestimatedsurvivalinunimprovedchannels)isrepeatedthesecondyear,thenetresultwouldbea400-600percentincreaseinproductionoverhistoricallevels.Thisisencouragingandindicatesthepotentialproductionthatcanbeattainedwithappropriatehabitatmodificationtechniques..(b)TernLakeEnhancementProjectTheU.S.ForestServicecompletedaspawningenhancementprojectonDavesCreekimmediatelybelowtheoutletofTernLake.Priorto'construction,thechannelgeometryandsubstrateinthisreachofthecreekprovidedonlymarginalhabitatforchinookandcohosalmonspawning.Thechannelwasrestructuredandsubstrateappropriateforchinooksalmonspawningadded.Thepool-rifflesequencewasestablishedwithnotchedlogs.Followingtwoyearsofoperation,increasedusebyspawningchinookaswellascohosalmonhasbeenreported(RalphBrowning,USFWS,pers•comm.,1984).Atwoyearprojectevaluationreportwillbeforthcomingbytheendof1984.ApplicationtoSusitnaRiverMitigation.TheTernLakeprojectisarecentdevelopmenta~devaluationsatthispointarepreliminary.Itdoesappearthatithasmetitsgeneralobjectiveofprovidingadditionalspawninghabitatinanareathatwasonlymarginallyusableearlier.d-'=:iJ(c)ChakachatnaDuringloggingpracticesinthelate1970s,abridgecrossingwasconstructedovertheChakachatnaRivernear11 --"\\~~~,"..;.....3-;dI..."J~J~.,;J--,J--"J----,.Jl--".J-lJJ,..>-iJtheconfluencewithStraightCreek.Toensurestabilizedabutmentsoneithersideoftheriver,guidebanksconsistingoflocalsands,gravels,andcobbleswereplacedalongthebanksofthemainchanneltodirecttheriver.Intheprocessofguidebankconstruction,materialwasexcavatedfromasloughchannelinthefloodplain.Thesloughwaslocatedupstreamoftheapproachroadwhichrequiredplacementofculvertsbeneaththeroadtoallowfreepassageofwater.Followingconstruction,theportionofthesloughabovetheculvertswasrectangularinshapereflectingtheexcavationprocessandmeasured50-70feetinwidthandabout400feetinlength.FlowthroughthisportionofthesloughduringthespawningseasoninOctoberwasabout2cfs.Belowtheroadcrossingexcavationwasminimalandthesloughtookonnaturalchannelcharacteristicsbeforefeedingintoasidechannelconnectedtothemainstemriver.Afieldsurveyduringthe1984spawningseasonindicatedthatapproximately200chumandsockeyesalmonusedthemodifiedportionofthesloughupstreamoftheroadcrossingforspawning.Inaddition,anearlierfieldsurveyduringthespringindicatedsockeyesalmonjuvenilesmayalsobeusingtheareaforrearing.Thiswasconfirmedinthefallsurveywhenseveralhundredsockeyejuvenileswereobservedintheheadwatersoftheslough.Thehistoricaluseofthischannelforspawningandrearingisunknown.ApplicationtoSusitnaRiverMitigationPlan.ThemechanicalmodificationofthissloughwithoutregardtopreservingthehabitatandthesubsequentuseofthischannelbyspawningchumandsockeyesalmonindicatesthatproperlydesignedandimplementedsloughmodificationsintheSusitnashouldmaintainifnotimprovetheexistinghabitatconditions.12 -,-,-"~......,~_-.J-1-,J~,oJ.JJ~-OJJJ(d)PortageCreekConstructionofsalmonenhancementprojectbytheU.S.ForestServiceandAlaskaDepartmentofTransportationiscurrentlyunderwayatPortageCreek.Agroundwater-fedspawningchannelmeasuringapproximately3,000feetinlengthand20feetinwidthhasbeendesignedprincipallyforchumsalmonbutmaybeusedbyallfivespeciesofPacificSalmonthatoccurinthearea.Inaddition,4rearingpondstotalingfiveacreshavebeenplanned.Expectedcompletiondateisfall1985.2.2.2-CanadianChumEnhancementProjectsInthelate1970stheCanadianDepartmentofFisheriesandOceansinitiatedaprograminSouthernBritishColumbiatoincrease"chumsalmonproductionbydevelopingnewspawningareasorimprovingexistingones(Listeretal.1980a).Theareasselectedforenhancementwerelocatedinoverflowchannelsgenerallyseparatedfromthemainriverexceptduringfloodconditions.Thesourceofflowthroughtheseareaswasgenerallygroundwater.Amongthetechniquesusedtoenhancethesespawningareaswereto1)provideaccessintothechannelsbyremovingobstructions;2)lowerthebedelevationofthechanneltoincreasegroundwaterflow,depth,andareaavailableforspawning;3)installweirstoincreasewaterdepthandcontrolgradient;and4)addsuitablespawninggravelswherepreviouslylacking.Chumsalmonegg-to-frysurvivalforsevenimprovedchannelsafterthefirstyearofoperationaveraged16.3percent,approximatelytwicetheaverage(7.9percent)documentedatsixnaturalspawningareasinBritishColumbia.Survivalattwoofthesites,33.5and20.7percent,exceededegg-to-frysurvivalpreviouslyreportedforchumsalmonundernaturalconditions,13 ,[rIrL"»"..."..J'1I,unI~nIJr..JnCJ"1-3~~~~L-JlJ...Je-...iandcomparedfavorablywiththeaverage(27percent)achievedataspawningchannelwithcontrolledflowatBigQualiumRiveronVancouverIsland.Moreover,onechannelthatdidnotsupportaspawningpopulationofchumsalmoninthepastreceivedover1,300spawnersinthefirstyearofoperationwitha20percentegg-to-frysurvival.Inchannelswheresortedgravelwasadded,bothhighandlowsurvivalswererecorded.Theremovaloffinematerialmayallowforgreatereggdeposition;however,theoverallsurvivalmayhavebeenreducedbecauseoffacilitatedaccesstointerstialspacebypredators.Theadvantagesofsortedgravelmayalsohavebeenmaskedbyothersitespecificbiologicalandphysicalfeaturesthataffectsurvivalsuchasdensityofspawningfishandchannelcharacteristicsthatdeterminethegradientandgroundwaterflow.ApplicationtoSusitnaRiverMitigationPlan.TheCanadianenhancementprojectsdemonstratedthatthroughvarioushabitatmodificationtechniquestheproductionfromhistoricalispawnedareascanbeimprovedbyincreasingtheamountofsuitablespawninghabitatandtherebyaccommodatingmorespawningpairsandbyattaininghighegg-to-frysurvivalrates.AsappliedtotheSusitnaRiver,imp~ovementofhabitatqualityinselected~reasofthemiddleSusitnaRivermaybeusedtomitigateforsomespawningareasthatwillbelost.2.2.3-WashingtonState(a)SatsopRiverChumEnhancementProjectsInrecentyearstheWashingtonStateDepartmentofFisherieshasundertakeninstreamchumenhancementprojectsalongtheSatsopRivertorestorechumsalmonrunsinthisareatotheirhistoricallevels(DaveKing,Wash.Dept.Fisheriespers.comm.,1984).Threeprojectscompletedto14 ,-~-~""'~'""\--J....,~-~_-.Jl"..;.;1-.Jdatehaveinvolvedmodificationstooldriverchannelsthatconveywateronlyduringhighflow.Intwoofthechannelsthesilt-sandsubstratewasexcavatedtoadepthtointerceptthewatertableandreplacedwith1/4to3inchleveledgravel.Inthethirdchannel,afterexcavation,thegravelinthechannelappearedsuitableforspawninganddidnotrequirereplacement.Thechannelsweregradedtoanapproximate2percentgradientand,wherenecessary,dikedoffattheupperendtopreventoverflowduringfloodperio~s.Althoughtheprojectshavebeeninoperationonlyfor1or2years,preliminaryevaluationsappearpromisingwithegg-to-frysurvivalrangingfrom38to78percent.Thehighestsurvivalwasdocumentedinthechannelinwhichthenativeg.ravelwasretained.Thischannelwasonlyadepressionbeforeitwasmodifiedandhadnotbeenusedbyfishpreviously.Itsdimensionswere7feetby500feet.Itreceived52fishitsfirstyearofoperation.Thelowdensity(reducedlikelihoodofsuperimposition)andtheprotectionaffordedagainstpredationbysmallergravelsandsandfoundinthenaturalsubstratemayhavecontributedtothehighsurvivalrate.Dimensionsand-"-"J_.~,JJdensitiesofspawningfishintheotherchannelswere:20feetby600feetwith600fishand15fe~tby1,000ftwith1,000fish.TheWashingtonStatecostsassociatedwiththeseprojectswere$15persquareyardforchannelswithreplacedgravelsand$11-12persquareyardwithoutreplacement.Duringtheconstructionprocesssomesandandsiltsweredepositedoverthereplacedgravelsandwereremovedwithagravelcleaningmachineatcostof$2-4persquareyard•....ApplicationtoSusitnaRiverMitigation.Theprojectswerepatternedafterthepioneering.41-~15SatsopRiverworkofthe .....,----,.-,,.,~_..,._-~--i....,---i-~-"""'\........;1-'-"_..-"~~-"--'.J.JCanadiansinBritishColumbiaandtheirapplicationtotheSusitnaRiveraresimilar.Theegg-to-frysurvivalfromtheWashingtonprojectsisparticularlyencouragingandindicatesthepotentialproductionthatcanbeattainedwithappropriatehabitatmodificationtechniques.Applicationt,oSusitnaRiverMitigationPlan.TheWashingtonStateprojectsemployedsimilartechniquetothoseinBritishColumbia.Theegg-to-frysurvivalhowever,wassubstantiallygreater.Thesurvivalratefromtheseproje~tsreemphasizesthepotentialfor_increasingthenaturalproductionofchumsalmonfryintheSusitnaRiverseveralfoldinselectedareas•(b)BakerLakeSubstituteSpawningBeachHistorically,anestimated95percentofthesockeyesalmonspawningintheBakerRiver,WashingtonsystemwasconfinedtotwobeachspawningareasonBakerLake.CompletionofthesecondBakerLakeDamresultedinthereservoirinundatingthelakeshorespawningbedstoadepthof60feet.Periodsofreservoirdrawdownalsocoincidedwithhatchingandfryemergence,withtheresultthatanyeggdepositionwithintheelevationrangeofdrawdownwouldbesubjecttodewateringorfreezing.Asamitigationmeasureasubstitutespawningbeachwasdevelopedtoperpetuatethisstockoffish.-'Studiesdonebeforethedamwasbuiltindicatedthatthespawningareaswereassociatedwithentrypointsofcoldwatersprings.Ataveragelakelevelsthetemperatureofthesespringswasindependentoflaketemperaturesand.variedonlyafewdegreesfromthetimefishspawneduntilfryemerged.However,duringfallfloodswhenthelakelevelrose5feetormore,thetemperatureinthespawningareasapproximatedlaketemperature,possiblyindicating16 ,'..",".-iJ,_.ill.~J,~J,J,.J,..Jl-,,-"e;.];-"1)JJJ~,JJ....;cessationofflowfromtehspringsduetohydrostaticpressure.Fallreservoirconditions(60feetofheadatthespawningareas)wouldbelikelytoeffectthesamechanges.Oneofthecriteriaforselectingasitefordevelopmentofasubstitutespawningbeachwasbasedonacquiringawatersupplywithtemperaturepatternsandwaterchemistrysimilartothosepresentinthelakeshorespawninggrounds.OfthetributarystreamsenteringBakerLake,onlyonepossessedsimilarwaterqualitywhiletheoth~r~differedremarkedly.Moreover,thisstreamdidsupportasmallnumberofspawningsockeye.PreliminarytestinginvolvedaI,000squarefeetbeachinwhichwaterdivertedfromtheselectedstreamprovidedupwellingthroughtheareabymeansofatimbergridwork.Followingthesuccessofthetestbeach,two15,000squarefeetearthenbeachpondswereadded.Eachaccommodatesapproximately1,500,adultfish.Thesourcewaterissuppliedthroughadiffusionsystemconsistingoftwo14-inchsupplymainsdrawingwaterfromadiversiondameachconnectedto50,four-inchpipesstationedthreefeetapart.Waterexitseachsetof50pipesthrough3/16inchholesdrilled8inchesapart.Thenetworkiscoveredwith1/4to3/4inchgravelandsuppliestheentireareawithupwellingwater.Thetotalflowrequiredforthesystemisapproximately3.75cfs.Theheaddifferentialbetweentheheadworksofthedamandthespawningpoolsisabout3feet.Thesystemhasoperatedsuccessfullyformanyyearswithexcellenteggdepositionefficiencyandegg-to-frysurvivalrangingfromalowof35percenttoahighof89percentofpotentialeggdeposition.Thesuccessofthisprojectmayhavebeendueinlargeparttoselectingasourceofwaterwithwaterquality17 ,'I'I-,,"-'J-,,.,J'I-li'1~,J,.-.il~d,-li-'1-Ii,d"J~Jcharacteristicssimilartothosepresentinthehistoricalspawninggrounds.ApplicationtoSusitnaRiverMitigationPlanning.SimilarmitigativemeasuresforthemiddleSusitnaRiverwhichproposetheuseofsupplementedwatersupplywillincludeevaluationsofthewaterqualityandtemperatureprofiletoinsuresatisfactoryresults.TheBakerRiverbeachspawningupwellingsystemdescribedindetailabovedemonstratesthatsuchasystemcanbeusedwithgreatsuccessforthosespeciesontheSusitnaRiver,i.e.chumandsockeyesalmon,thatappeartodependonupwellingforspawning•(c)ColumbiaRiverSpawningChannelsConstructionofdamsontheColumbiaRiverhasbeenresponsiblefortheinundationandsubsequentlossofthehistoricmainstemspawninggroundsforfallchinook.ThenaturalhabitatforsalmonaboveBonneville,thedamfarthestdownstream,hasdeterioratedasaresultofincreasedwatertemperatures,pollution,predationand-decreasedvelocities(Meekin,T.K.1967).Althoughtheseenvironmentalconditionshaveaffectedseverallifestages,lossofsuitable"habitatforspawninghasbeentheprincipalconcern.TheWashingtonDepartmentofFisheries,facedwiththedecisionofhowtoperpetuatetheColumbiaRiverruns,consideredtwoalternatives.Thefirstwastodevelopfishhatcheryprogramsandthesecondwastoconstructartificialspawningchannelssimulatingnaturalconditions.TheDepartmentoptedforthesecondalternativeandin1954initiatedaprogramtoevaluatethephysicalhabitatrequirementsforspawningchinooksalmonsothatartificialspawningchannelscouldbeconstructedtomitigateforthe18 I'lJr1,_,[['L.'[[:[[-,.,*'lossofmainstemspawningareas.ThisresultedintheconstructionoftheMcNarySupplementalSpawningChannelin1957,thefirstofitskindforthepropogationofchinooksalmon.TheCanadianDepartmentofFisheriesandOceanshadexperimentedwithartificialspawningchannelsforpinksalmoninBritishColumbiasince1954andhadreportedgoodegg-to-frysurvival(HoustonandMackinnon1957).ThespawningchannelprogramexpandedwiththecompletionoffivehydroelectricprojectsaboveMcNaryDam;ChiefJosephDamin1957,PriestRapidsin1960,RockyReachin1961,Wanapumin1967andWellsin1967.Eachofthesedamsincorporatedfishpassagefacilities,exceptforChiefJosephDamwhichmarkedtheendpointforupstreammigrationofanadromousfish.Asmitigationfortheinundatedspawninggrounds,spawningchannelswerealsodevelopedatPriestRapids,RockyReach,andWellsDams•Evaluationsoftheperformanceofeachofthesechannelsinmaintainingthemainstemchinookstockswereconductedduringeachyearofoperation.Theresultsaresummarizedbelow.[[[r'"L,[LL[[[(i)McNaryTheMcNaryspawningchannelconsistedof12spawningrunsmeasuring22by175feetwitheachrunseparatedbyapool.Gravelsizerangedfrom0.5to3inches.Flowthroughthechannelwas92cfs.Asthis'wasthefirstspawningchannelcompleted,severalimportantconclusionswerederivedthatwereofuseindevelopmentofsubsequentchannels(Meekin1967).1)Itwasdemonstratedthatchinooksalmonwouldvoluntarilyenterachannelwithphysicalconditionsresemblingnaturalonesandspawn.19 -,,-.,-.,--'--,-OJ.."-~~jJ"J"'"'IJ'-'!!-11~J,j;,~.J....2)Thepoorreturnofmarkedfishindicatedthataself-perpetuatingrunhadnotbeenestablished.3)Theallocatedareaof55squarefeetperfemalewasinsufficienttosupportspawningandatleast165squarefeetwasrequired.4)Lowegg-to-frysurvivalresultedfromhighwatertemperatures,siltdeposition,andsuperimposition.5)Attemptstotransplantfallchinookindigenoustotheupperreachesoftheriverresultedinexcessivepre-spawningmortality.(ii)RockyReachTheRockyReachSpawningChannelwasconstructedasamitigationfacilityforlossofchinooksalmonspawninggroundsresultingfromtheconstructionofRockyReachDam.The1,000-footlongspawningchannelwasdesignedtoaccommodate330pairsofchinooksalmon-thenumberoffishestimatedtospawnhistoricallyinthereachinundatedbythereservoir.Theresultsofsevenyearsofoperationwere:1)Highprespawningmortalityofadults.2)Lownumbersandsmallfryproductionwithcorrespondinglysmallsizeandfewjuvenilesreleased.3)Extremelylowadultreturns.4)Highoperationalcosts•20 ,.,"--"~-,"l-..-j-1--iJ1~"""'\-.J'-,~~J--,"-~~4--;J---,."--:.-,-0~<,4JJPrespawningmortalityresultedfromexcessivehandlingcombinedwithhightemperatures,whichincreasedthesusceptibilitytodisease.Egg-to-migrantsurvivalswerequitevariableoverthesevenyearsofoperationwiththreeyearsgreaterthan40percentandtheotherfouryearslessthan10percent.Factorsthoughtresponsibleforthelowsurvivalincludedsuperimposition,predationbyjuvenilecoho,andnitrogensupersaturation(Meekineta1.1971).Thepoorretu~nsofadultfishmayhavebeenattributabletolowsurvivalduringoutmigrationorperhapsstrayingofadults,sincethechannelwaterwaspumpeddirectlyfromtheColumbia;however,significantnumbersofmarkedadultswerenotobservedatupstreamdamfishladders.Insummary,thechanneldidnotfulfillitsintendedpurposeofmaintainingaviablerunofchinooksalmonthathistoricallyspawnedintheRockyReachsectionoftheColumbia.Thechannelispresentlybeingusedasacohoeggincubationchannelandrearingstation.(iii)PriestRapidsThePriestRapidsSpawningChannelwascompletedin1963asamitigationmeasureforthelossofchinooksalmonspawninggroundsfollowingtheconstructionofPriestRapidsandWanapumDamsontheColumbiaRiver.Thechannelwasapproximately6,000ftanddesignedtoaccommodate2,500pairsofchinookspawners.21 [[[[[[I'"L~~IUruI:I-.~[[nH'"u1-"1-wi--'"L~.l-'l(""j"j....JTheperiodofchanneloperationfrom1963to1967wascharacterizedbysubstantialprespawningmortalityandpoorjuvenileproductionrangingbetween5and14percentofthepotentialeggdeposition.The1967-68seasonmarkedatransitionpointinthechanneloperation.Forthreeseasons,productioninthechannelwasconsistent,andwasgreaterthan50percentofeggdeposition(Allen1968).Theincreasedproductionofthelateryearswasattributedto:1)Decreasedsuperimpositionresultingfromreducednumberofadultsinthechannelandtheirforceddispersion.2)Lowerincidenceofdiseaseandeliminationoftreatments.3)Maintenanceofadequateflowsthroughtheentireincubationperiods.4)Negligibleintroductionofwind-blownsanddepositsintothespawningchannel.However,thischannel,liketheothers,sufferedfromthelackofsignificantadultreturntothefacilityapparentlyduetothepoorseawardsurvivalofoutmigrantsandahighrateofstrayingforreturningadults.(iv)WellsSpawningChannelTheWellsSpawningChannelwasdesignedtoaccommodate3,000femalespawners.Thespawningchannel,measuring6,000feet,beganoperationin1967.Forthefirstfiveyearsofoperation,fry22 ,""'1-,--1-"~...J'."-J"":--,--....~--'"\passagethroughnumerousdamsandpredator-infestedwaters.Thenetresultwasthatselfperpetuatingrunscouldnotbemaintained.Intimethefacilitieswereconvertedtorearingar~as.forhatcheryproducedfry.TheoverallfailureoftheColumbiaRiverSpawningChannelprogramwaslargelyattributabletoenvironmentalconditionsuniquetothatsystem.Severalofthechannels,particularlyWells,weresuccessfulinproducingfryfromnaturallyspawningadults.Extraneousfactorssuchaslowsurvivalofoutmigrantsandpossiblestrayingofreturningadults,however,contributedtotheprogram'seventualdemise.ApplicationtoSusitnaRiverMitigationPlan.TheColumbiaRiverSpawningChannelsprovideevidencethatchinooksalmonwouldvoluntarilyenterandsuccessfullyspawnandincubateinanartificiallyconstructedchannelifconditionsresemblingtheJnaturalenvironmentweresimulated.Inaddition,-4theeventual'failureofthechannelsandreplacementwithartificialincubationfacilitiesandrearing-J-'"--'pondsemphasizetheimportanceinalternativemitigationoptionsshouldhigherprioritymeasuresoccur.23developingfailureof 3 -SUSITNARIVERMITIGATIONPLANiItisexpectedthatthedistributionandabundanceoffishspeciesdownstreamoftheproposedSusitnaHydroelectricProjectwillchangeasaresultofprojectoperation.Theimpactassessmentspresentedinthisreportweredevelopedfor·themaximumpowerflows(CaseP-l)whichincludesnominimuminstreamflowrequirements,andthreeofthepotentialprojectflows(CaseC,CaseEV,andCaseEVI),whicharebasedondifferentminimuminstreamflowrequirements.ThedevelopmentoftheseflowregimesarediscussedinHarza-Ebasco(1984b).Thegeneralimpactsrelatedtoallflowregimesarediscussedinthefollowingsection;specificdifferencesinthedegreeofimpactamongthevariousflowregimesarediscussedinsubsequentsections.TheimpactassessmentslinkpredictedphysicalchangeswithhabitatutilizationtoprovideaqualitativestatementofimpactslikelytoresultfromtheSusitnaHydroelectricProject.ImpactissueshavebeenidentifiedandrankedbyproceduresestablishedbytheSusitnaHydroelectricProjectFishandWildlifeMitigationPolicy(AcresAmerican1982).3.1-ImpactAssessment3.1.1SpawningHabitatUtilizationinSloughsandSideChannelsTheareaofspawninghabitatutilizedwithinselectedsloughsandsidechannelswasestimatedbydigitizingtheactualareasspawnedduringthe1982,1983,and1984spawningseasonsasoutlinedbyADF&G(unpublishedmapsofspawningareas).The1981datawerenotusedbecausethehighflowsandpoorvisibilityduringthespawningseasonpreclud~ddefinitionofspawningareas.TheareasoutlinedbyADF&Gindicategeneralareasofspawning,nottheareaactuallyexcavatedbyspawningfish.Forexample,acircumscribedareaof10,000squarefeetmayhavehad50spawningpairsoffishwidelydistributed,whileasimilarareaelsewheremayhaveaccommodatedseveralhundredspawningfishoverthecourseoftheseason.Theareasspawned24I forallthreeyearswereclassifiedascompositeortotalareas.Compositeareaswereobtainedbysuperimposingmapsofspawnedareasforeachyearandmeasuringtheareaspawnedoneormoretimes.Totalareawasthesumoftheareaspawnedineachofthethreeyears.Figure6illustratesthedifferencebetweencompositeareaandtotalarea.TheratioofthecompositeareasspawnedtothetotalareausedoverthethreeyearsispresentedinTables7through13forSloughs8A,9,9A,11and21andSideChannel21(ADF&G1984c).Theratioofthecompositeareatototalareaservesasanindexoftheamountofarearepeatedlyspawnedduringthethreeyears.Ifthesameareawereusedeachofthethreeyearstheratiowouldbe.33.Greatervaluesindicatelessrepeateduseofspawninghabitat.Avalueof1.0indicatesdifferentareaswereusedineachofthethreeyears.Thecompositeareasspawnedcanbeconsideredrepresentativeofthepotentialspawninghabitatwithinthesloughsandsidechannelsevaluatedifthefollowingconditionsaresatisfied:1)Sufficientnumbersoffishannuallyescapedtothesloughsandsidechannelstooccupygeneralizedareasofavailablespawninghabitat.2)Flowsduringthe1982,1983,and1984spawningperiodsprovidedaverageaccessandpassageconditionstospawninghabitatthatwererepresentativeoftheconditionsthelongtermflowrecordhasprovided.3)Theperiodsinwhichaccessandpassageconditionswereprovidedbythe1982'-1984flowscoincidedwiththeavailabilityofspawningfish.Furtherevaluationoftheaboveconditionswillbeundertakenwhentheflowandescapementrecordsforthe1984seasonbecomeavailable.Thefortuitousoccurrenceofahigh1984escapementandaperiodofhighflowcoincidentwiththehistorical25 --'7-"j--""_.J--__-J-'-',c"",.....J}--"beginningofthepeakspawningperiodduringthe1984seasonshouldprovideavaluabledatabaseforevaluationofconditionsthatallowedaccesstoandutilizationofmostofthepotentialsloughandsidechannelspawninghabitatinthemiddleSusitnaRiver.3.1.2ProjectRelatedPhysicalChangesinSloughsandSideChannelsOperationoftheSusitnaHydr~electricProjactwillmodifytheannualflowandtemperatureregimeoftheSusitnaRiver,thus·causingphysicalchangesinsloughsandsidechannelsinthemiddlereach.Ingeneral,flowsduringprojectoperationwillbelessthannaturalflowsduringJune,July,August,andSeptemberandhigherthannaturalflowsintheremainingmonthsastherese~oirisdrawndown.Projectflowswillberelativelyconstantthroughouttheyearascomparedwiththenaturalvariabilityofflows•TheprojectflowregimewouldcausethefollowingphysicalchangesinsloughsandsidechannelsoftheMiddleSusitnaRiver:ReducedbackwatereffectsduringsummerReducedfrequencyofbreachingduringsummerReducedgroundwaterupwellingIncreasedfrequencyofwinterovertoppingSusitnaRiverdischargespresentedinthisreportareflowsattheGoldCreekgagemaintainedbytheUSGS.(a)BackwaterAbackwaterareaformsatthemouthofasloughorsidechannelifthestageinthemainstemisgreaterthanthestageoftheflowinthesloughorsidechannelatitsmouth.Ifthemainstemstageriseswithnochangeinflowinthesloughorsidechannel,thelevelofthebackwater26 ...,.,-"-v"--"-."-'-.".J-,.,.i-'(b)(c)increasesandtheaerialextentofbackwaterinfluencemovesupstreaminthesloughorsidechannel.Ifthemainstemstagedrops,thenthebackwaterlevelalsodropsanditslengthisshortened.Thedropinmainstemstagecanbesufficienttoeliminatethebackwatercompletely;thestageandcorrespondingmainstemdischargeatwhichthisoccursvariesfromsitetosite.Thestageofthebackwatermaybedefinedbythemainstemdischargethatformsthebackwater.ProjectoperationwillgenerallycauseadecreaseinbackwaterareaandstageduringJunethroughSeptember.BreachingAsloughorsidechannelbreacheswhentheflowovertopstheupstreamend,orhead,ofthechannel.Breachingisdirectlyrelatedtomainstemdischarges;asthedischargeincreases,thestage.increasesandwhenstageexceedstheelevationofthetopofthebermatt~eheadofthesloughorsidechannel,flowisdivertedthroughthechannel.Furtherincreaseinstagewillcauseadditionalflowtopassthroughthesloughorsidechannel.Projectoperationwillgenerallycauseasignificantdecreaseintheamountoftimethatasloughorsidechannelbreaches.GroundwaterUpwellingGroundwaterflowsoutof(upwellsfrom)thebedofasloughorsidechannelwhentheelevationofthebedislessthanthatofthelocalgroundwaterlevel.Studieshavebeenconductedtorelatetheflowandtemperatureofthemainstemtoupwellingquantityandtemperatureinsloughsandsidechannels(APA1984).Althoughacompleteevaluationofthesourcesofgroundwaterwasnotconducted,theapparentgroundwaterupwellingcomponentofsloughflowwasisolatedfromthesurfaceinflowcomponentandrelated27 i~""'--'3~...,.~J--",...j.~JJ<-,J~~--"'...J;J.--,tomainstemdischargeatSloughs8A,9,and11.Atthesethreesites,variationsintheinferredupwellingcomponentsrangedfrom0.0001to0.00035ofcorrespondingvariationsinmainstemdischargemeasuredatGoldCreek'(APA1984).Relationshipsweredevelopedintheformofregressionequationsforinferredupwellingcomponentasafunctionofmainstemflows;thesewereusedinmakingapreliminaryanalysisofprojectrelated'changesinthegroundwaterupwellingcomponentofsloughdischargeasdescribedinAppendixA.Thetemperatureofthegroundwaterupwellingappearstoremainrelativelyconstantatavalueapproximatelyequal1984)•Projectoperationduringwinterwouldaffectupwellinginthesloughs.ThehigherprojectflowsinconjunctionwithincreasedwatertemperatureswillchangetheiceprocessesinthemiddleSusitnaRiver.Asthemainstemformsanicecover,thestageincrease,sbecauseofbackwatereffectsfromfraziliceparticlesandpansjamminginconstrictedareasorbuildingupondownstreamjams.Thusriverstagewithanicecoveratlowflowmayapproximatethestageofamuchlargerflowintheopenchannelconditionsofsummerflows.Underprojectoperation,theupstreamedgeoftheicecoverwillvaryfromRM125toRM142dependingonmeteorologicconditionsandtheelevation(andthustemperature)atwhichwateriswithdrawnfromthereservoir(Harza-Ebasco1984a).Upstreamofanicecover,thestageintheriverwoulddecreaserelativetonaturalstageexperiencedunder28 ..."-,-,-,-'-,-"-,-,,Y-~(d)anicecover.Accordingtopreliminaryupwellingstudies,thiswillresultindecreasedgroundwaterupwellinginsloughsandsidechannelsthroughoutthewinter.WinterOvertoppingThestageincreaseduringicecoverformation(winterstaging)wasdescribedbrieflyintheprevioussectioninrelationtothereducedupwellingatlocationsupstreamfromtheicefront.Withprojectflowshigherthannaturalflowsduringwinter,thestagingeffectwillbehigherduringprojectoperationdownstreamfromtheicefront.Thus,theprobabilityofbreachingcausedbyicestagingatanddownstreamfromtheicefrontisalsogreater.Undernaturalconditions,thestagingeffectsoccasionallycausesloughandsidechannelovertopping.Whenanicecoverforms,shoreicedevelopscausingflowchannelization(R&MConsultants,Inc.1983).Theshoreicemayactasabarriertocontaintheflowandpreventthemainstemfromovertoppingthesloughberms(Figure7).However,underhighermainstemdischarges,theprobabilityofovertoppingwillincrease.Figures8through12,derivedfromicecoverpredictionmodeling(Harza-Ebasco1984a),maybeusedtopred·ictpossibleovertoppingeventsundernaturalandprojectwinterflowregimesatSloughs8A,9,9A,11and21.Theydonot,however,identifytheprobabilityordurationofactual·eventswhicharedependentonotherfactorsbesidesmainstemstage..,.,-"~3.1.3RelationshipBetweenPhysicalChangesandAvailableHabitatinSloughsandSideChannelsThephysicalchangesassociatedwithprojectflowsasdiscussedinSection3.1.2woulddirectlyaffectthequantityandqualityofspawningandincubationhabitatbyreducingtheareathatsatisfiesthephysicalrequirementsoftheselifestagesor29 ~,~_-iJ-.indirectlyeffecttheavailabilityofspawninghabitatbyrestrictingaccesstothoseareas.(a)DirectEffects1,-J1JJ(i)ReducedBackwaterBackwatereffectsintheareaofthesloughmouthundernaturalconditionsprovidegreaterdepthsintheaffectedzone'thanwouldbeprovidedbylocalsloughflow.Projectflowswillsubstantiallyreducethebackwaterzoneinsomesloughsresultinginadecreaseinthesurfaceareawithsuitablespawningdepthsandalossofspawninghabitatatthesloughmouth.Thedegreeoflossisdependentontherelativespatialdistributionofavailablespawninghabitatundernaturalandprojectconditions.'l~),-,'--,.~.J"".J--,->JJJ,.->(ii)ReducedFrequencyofBreachingFlowsBreachingflowsalsoprovideadditionalspawninghabitatwithinthesloughandsidechannelsbyincreasingtheamountofareawithsuitablespawningdepths.Projectflowswillsubstantiallyreducethefrequencyofbreachingflowsandthusdecreasethepotentialspawninghabitat.Theamountofhabitatlostisdependentonthesitespecificfrequencyofbreachingflowsundernaturalconditions.Spawninghabitatprovidedatbreachedconditionsinsiteswithrelativelyhighbreachingdischarges(lowfrequencyofoccurrence)isgenerallyofinsufficientdurationforfishtoeffectivelyutilize;ifsuchhabitatwereused,itwouldlikelyresultindewateringandfreezingoftheembryo.Spawninghabitatprovidedunderbreachedconditions30 '",..,.~-'~---'-,J-,-'~.......J;,-',.....-,~.-J-"-.J.,.J-,-.J-"-'inchannelswithrelativelylowbreachingdischarges(highfrequencyofoccurrence)canbeeffectivelyutilized;embryohaveahigherprobabilityofremainingwettedandunfrozenatsuchsites.Theinfrequentbreachedconditionsunderprojectflowswouldresultinalossofthisspawninghabitat.Thequantityofhabitatlosswoulddependontherelativespatialdistributionofavailablespawninghabitatundernaturalandprojectconditions.(iii)ReducedUpwellingReducedmainstemflowsduringthespawningseasonwouldalsodecreasetheamountofupwellingintheslough.Chumsalmonprefertospawninareaswithupwellingflow.Thereductionintherateandaerialextentofupwellingwouldreducethequalityandquantityofavailablespawninghabitat.·Winterflows,althoughhigherthannatural,wouldresultinreducedupwellinginsloughsupstreamoftheicecoverbecausethestagingeffectsduringiceformationwillnolongeroccur.Adecreaseintherateandarealextentofupwellinginwintermaydecreasethequalityofincubationhabitat.(iv)IncreasedFrequencyofWinterOvertoppingProjectwinterflowswouldbehigherthanflowsundernaturalconditions.Thus,theprobabilityofbreachingcausedbyicestagingat,anddownstreamfrom,theicefrontisalsogreater.Undernaturalconditions,thestagingeffectsoccasionallycausesloughovertopping.Forthosesloughswhichareovertopped,theinfluxofnearfreezingwaterand.l!lubsequenticeformation31 [[willresultinahigherrateofembryomortality(ADF&G1983b),reducedgrowthofsurvivingembryo,r-->.:andreducedjuvenileoverwinteringhabitatL.-_..oi(Harza-Ebasco1984b).(b)IndirectEffects~"'I--,<=.:Ir-,I--'~I'--"'-"r----",~..J'"_."....J~31~~Thephysicalchangestosloughsandsidechannelsresultingfromprojectoperationwillreduce-thefrequencyofsuccessfulpassageintoandwithinthesesites,andthustheavailabilityofupstreamhabitats.Dur:ingtheopenIwaterseason,thedepthatanylocationinasloughorsidechannelisafunctionofthecumulativeeffectofbackwater,breaching,andlocalflowinthechannel.Localflowisgeneratedbysurfaceinflow(surfacerunoffandtributaryinflow)andgroundwaterupwelling.Theinfluenceofmainstemdischargeonbackwater,breaching,andgroundwaterupwellingwasintroducedpreviously.Variationsinsurfaceinflowarenotdependentonthemainstemdischargedirectly,eventhoughthereissomecorrelationthroughtheirmutualdependenceonprecipitation.Thus,aconsiderationofprojecteffectsonflowdepth,andthuspassagereaches,mustaddresschangesinbackwater,breaching,and'groundwaterupwelling,and addunchangedsurfaceinflowtotheseparameters•Decreaseinsloughorsidechanneldepthresultingfromprojectoperationisdependentonthelocationwithinthesloughorsidechannel.Relativechangesindepthgenerallydecreaseinthedownstreamdirectionforagivenchannelconfigurationandwillalsobegreaterforriffleconfigurationsthanforpoolconfigurations.Forexample,ifapoolis3feetdeepandtheadjacentriffleis0.5feetdeep,thena0.25-footreductioninbothwillhaveamuchgreatereffectintherifflethanthepool.Thus,the32 Assess~~ntoftherelativeimpactsofprojectoperationonpassageconditionscanbeaccomplishedbyidentifyinghowoftenacertaindepthoccursundernatural.andprojectconditions.Forexample,specifieddepthforsuccessfulpassageatapassagereachlocatednearthemouthofasloughmaybereachedorexceeded80percentofthetimeduetobackwateronly,20percentofthetimeduetobreachingonly,and40percentofthetimeifanaveragegroundwaterweresupplementedbysurfaceinflow.Sincebackwater,breaching,andgroundwaterupwellingarefunctionsofmainstemdischarge,thefrequencyofacertaindepthbeingequalledorexceededcanbeobtainedfromtheflowdurationcurvefortheperiodofinterest.Anapproximationofthefrequencyofsurfaceflowcanbeobtainedfromaprecipitationdurationcurve,whichisrelatedtothesurfaceflowthrougharunoffcoefficient.Ifitisassumed,tobeconservative,thatthebackwater,breaching,andprecipitationeventsarecoincident,thenintheexampleabove,thefrequencythatthespecifieddepthisequalledorexceededis80percent,correspondingwiththefrequencyduetobackwater.Theevaluationsofprojecteffectscanaddressthefrequenciescorrespondingtoprojectoperation,whichmaybe0percentofthe·timeduetobackwateronly,0percentofthetimeduetobreachingonly,and35percentofthetimeifaveragegroundwaterweresupplementedbytheunaffectedsurfaceinflow.Thus,theeffectsoftheprojectforthepassagereachinthisexampleisreductioninthepercentoftimethataspecifieddepthforsuccessfulpassageisequalledorexceededfrom80percentto35percent.Thisrelativechangeisfairlytypicalofthechangethatmayoccurtoapassagereachnearthemouthofasloughorsidechannel,whileachangefrom10percentto8percentmaybemoretypicalofapassagereachlocatedfartherupstreaminthe33 site..AnalysesinAppendixAprovideresultsindicatingprojectinfluenceonpassagereachesinselectedsloughsandsidechannelsofthemiddleSusitnaRiver.34 maintaininganacceptableamount-,limitingspecies/lifestageswhich_-.iImaintainedusingothertechniques.~-,_.,11....,-'~__J3.2-MitigationOptionsForthemiddlesectionoftheSusitnaRiver,alteredflowswouldaffectthefishpopulation.Undernaturalconditions,mainstemdischargesarehighinlateMay,June,July,August,andearlySeptemberanddecreaseduringSeptemberandOctobertolowflowsthroughoutthewinter(Figure13).Hydroelectricpowerisdesiredprimarilyduringwinterandwaterisretainedduringsummertofillthereservoir.Flowsunderprojectoperationwouldbemuchmoreuniformthroughouttheyearandthuswouldnecessarilybehigherinthewinterandlowerinthesummerthannaturalflows.ThreelevelsofmitigationcanbeappliedtomitigateforimpactstothefishpopulationinthemiddleSusitnaRiverresultingfromprojectoperation;theseareflowrelease,habitat.modification,andartificialpropagation.Thepurposeofflowreleaseisto.avoidorminimizetheimpactsbyofsuitablehabitatforcannotbeeconomicallyThepurposeofhabitatmodificationistominimize,rectify,orreducetheresidualimpactsremainingafterimplementationoftheflowreleasemitigation;thiswillbeaccomplishedthroughmodification·ofexistinghabitatstomaintainorenhance·thenatural-'productivityofthehabitat.Thepurposeofartificial..J_.,..Jpropagationistocompensateforlosseswhichcannotbeeconomicallymitigatedforbyflowreleaseandhabitatmodification.3.2.1-FlowRelease(a)ImpactIssueTheproposedhydroelectricdevelopmentontheSusitnaRiver--'isforpowerproduction.35Tomaximizepowerandenergy ~___.J-"-,-,..~,"--.;-,-',-.Jj--,JJ-3-".3Jbenefits,thedischargedownstreamofthedamswouldfollowCaseP-1,presentedinTable14(Harza-Ebasco1984b).ThisscheduleofflowsvariesgreatlyfromthenaturalmeanmonthlyflowsrecordedatGoldCreek(Figure13).CaseP-1flowsaverage9,700cfsduringboththewinter(Octoberthroug~April)andsummer(MaythroughSeptember)periods(Harza-Ebasco1984b).Duringwinter,flowswillgraduallyincreasetoamaximumofapproximately12,000cfsinDecember,followedbyagradualdecreasethroughtherestofthewinter.MeanDecemberflowcanbeashighas14,000cfsinsomeyears.Minimummonthlymeanflowswouldrarelybelessthan7,000cfsduringthewinterperiod(Harza-Ebasco1984b).Summerflowswouldexhibitmorevariabilityaroundthemeanof.9,700cfs.Duringhighflowyears,meanflowinMay,June,andJulycouldapproach20,000cfswhilemeanflowinAugustandSeptembercouldbegreaterthan20,000cfs(Harza-Ebasco1984b).Inlowflowyears,theflowcouldbe4,500cfsforextendedperiods.Summerflowwouldbelessthan7,000cfsabout30percentofthetime(Harza-Ebasco1984b).ThecomparativelylowflowsduringAugustandSeptemberwouldrestrictmovementofadultsalmonintoandwithinsloughs.Atamainstemdischargeof6,000cfsunderCaseP-l,backwatereffectsatthesloughmouthswouldbenegligible,breachingofthesloughswouldrarelyoccur,andtheupwellingcomponentoflocalflowwillbeless.Projectflowswouldalsoreducethespawninghabitatavailableduetoreducedbackwater,breaching,andgroundwaterupwellingeffects.Projectflowinthemainstemduringwintercancausereducedupwellingupstreamoftheicefrontandincreasedpotentialforovertoppingdownstreamoftheicefront.36 -,-'-,--'~.-,-,-'""'",""-.J............,-,....J-,_J.,....J-i-.J.J....JJuvenilesalmonrearinghabitatwouldbesignificantlyreducedunderCaseP-lflowsduringbothsummerandwintermonths.Flowsof4,500cfsinsummermonthswouldresultinasubstantiallossofthemainstemandside-channelrearinghabitatpresentlyusedbychinookjuveniles(Harza-Ebasco1984b).Mainstemdischargesof9,000cfsatGoldCreekarenecessarytomaintain75percentoftheexistinghabitatbeingusedbychinookjuveniles(Harza-Ebasco1984b).JuvenileoverwinteringhabitatwouldalsobeadverselyaffectedunderCaseP-lflows;theincreasedwintermainstemstagewould'overtopthesloughsmorefrequentlyandmayresultindisplacementormortalityofjuveniles.(b)MitigationOf.theprojectflowscheduleswhichhavebeenidentified(Harza-Ebasco1984b),.threemitigationflowschedulesarediscussedtoreducetheadverseimpactsofCaseP-l.CaseC,previouslyselectedasprimaryenvironmentalflowcasepresentedintheLicenseApplication,isintendedtomitigatespawningimpacts.CaseEVisdesignedtoreducebothspawningandrearinghabitatimpacts.TheAlaskaPowerAuthority'sdesignatedflowcase,CaseEVI,isselectedprimarilytoreducelossofchinookrearinghabitat(Harza-Ebasco1984b).(i)CaseCTheenvironmentalflowcomponentsofCaseCaredesignedtomaintainsuitableconditionsfortheupstreammigrationofadultsalmonduringthesummerandtoprovideaccesstosidesloughsbychumsalmonforspawningduringAugustandSeptember(Harza-Ebasco1984b).MainstemflowsinAugust"andSeptemberareconstrainedtoprovideaminimumof37 --'12,000cfs(Figure14)toincreasethefrequencyofsalmonaccesstoandwithinsidesloughs.Nomaximumflowconstraintsthroughouttheyearareestablished.IncomparisontoCaseP-1flows,CaseCwillimprovethefrequencyofsalmonpassageintoandwithinsloughsandsidechannelsinAugustandSeptember.Amainstemdischargeof12,000cfsundertheCaseCflowschedulewillincreasethebackwatereffectsin,_.~sloughmouths.atthisflow.BreachingofsidechannelsmayoccurThelocalflowinsidesloughswill~,-,----!-,-'-'---',--"alsoincreaseduetoupwellingrelatedtomainstemdischarge.However,thelackofaconstrainingmaximumflowadverselyaffectsrearingandoverwinteringhabitataswellasincubatingconditions;thelowmainstemflowsof6,000cfsinsummermonthspriortoAugustunderCaseCwillresultinthelossofmostoftheexistingchinookjuvenilehabitatcurrentlyinuse(Harza-Ebasco1984b).Thepotentialmagnitudeoftheseadverseimpactspromptedtheidentificationofmoredetailedandrefinedenvironmentalflowschedules(Harza-Ebasco1984b).(ii)CaseEVCaseEVflowconstraintsaredesignedtomaintain75-->percentoftheexistingchumsalmonsloughspawninghabitatand75percentoftheexistingchinookC~5salmonsidechannelrearinghabitat.C'\00\7-JSpawninghabitatwillbepartiallypreservedbymainstemflowswhichareconstrainedtoaminimumof38 conditions.CaseEVscheduledflowsincludeatwo-dayperiodinAugustwhenthemainstemdischargewillapproach18,000cfsinordertoimproveaccesstochumsalmonspawninghabitat;thehigherflowwillincreasebreachingandbackwatereffects.At18,000cfs,breachingwillnotsubstantiallyamelioratesalmonpassageinthesloughsofprimaryspawningimportance(Sloughs8A,9,9A,11and21).Backwatereffectsmayprovidepassagethroughanadditionalpassagereachupstreamofthereachespassableduetobackwatereffectsat12,000cfs..,.,~,,J"",.....,-''-,-"'j~\:~12,000cfsduringAugustandearlySeptemberwhenchumsalmonaremigratingandspawninginsloughsofthemiddleSusitnaRiver(Figure15).CaseP-lflowsareprojectedtoapproach6,000cfsduringthistime.Amainstemdischargeof12,000cfswillcreatebackwatereffectsincreasingthefrequencyofpassageinthemouthsofmanysloughsandsidechannels.Breachingmayoccurinsidechannels.GreatermainstemflowsarerequiredtobreachthesloughscontainingthemajorityofthespawninghabitatinthemiddleSusitnaRiver(Sloughs8A,9,9A,11and21).~LocalsloughflowsareanticipatedtoincreasefortCaseEVincomparisontolocalflowsunderCaseP-l.'SJ'Anincreaseof6,000cfsfromCaseP-lflowsof\6,000cfsisestimatedbasedoncurrentinformation-.:r(APA1984)toincreasesloughflowsfrom0.5cfsin\h;~\SSloughs8A,9and11to4cfsinSlough21.Local~flowswillbelessthanlocalflowsundernaturaloo~u\\Localflowduringthefallspikingflowof18,000cfsisanticipatedtoremainapproximatelyat39 thelevelsofthelocalsloughflowatamainstemdischargeof12,000cfs.Theshortdur~tionofthehigherflowandtheprobableunsaturatedconditionofthesubstrateabovethe12,000cfsmainstemstagemayresultindelayedanddampedresponseofthelocalflowtothemainstemdischargeincrease.Atleast75percentoftherearinghabitatcurrentlyinusebychinookjuvenileswillbemaintainedduringthesummermonthsbytheCaseEVminimummainstemdischargeof9,000cfs(Harza-Ebasco1984b).Theminimumdischargewillbesimilartoprojectdischarges55percentofthetime;thepredictedaverageflowduringthesummerperiodwillbe11,400cfs(Harza-Ebasco1984b).Thespikingflowsinspringandfallmaycausedisplacementofchinookjuveniles.TheincreasedmainstemflowstabilitymayimprovetheoverallqualityoftheremainingrearinghabitatunderCaseEV(Harza-Ebasco1984b).WinterflowsunderCaseEV,incomparisontoCaseP-l,willdecreasethefrequencyofbreachingflowsdownstreamoftheicecoverandreducetheamountofupwellingupstreamoftheice.cover.Themaximumwinterdischargesof16,000cfswillassistinmaintainingviableembryohabitatwithinthesloughs;winterovertoppingunderCaseEVwilloccurmorefrequentlythanundernaturalconditionsdownstreamoftheicefront.UpstreamoftheicefrontunderCaseEV,thedecreasedmainstemstagefromCaseP-1mayresultinreducedupwelling.Bothcaseswillresultindecreasedupwellingupstreamoftheicefrontascomparedtonaturalconditions.40 ,-,-~-,-,-,-'-1--'---"-"--'-,.J---'__..i-J-~--'-"-,-Jl(iii)CaseEVflowsisdesignedforpreservationof75percentofthechumspawninghabitatand75percentofthechinookrearinghabitat;however,additionalmitigationmaybenecessarytomeetthesegoals.AdditionalmitigationalsowouldbenecessaryforCaseEVwinterflows.CaseEVICaseEVIisdesignedtomaintain75percentoftheexistingchinooksalmonsidechannelrearinghabitatinallyearsexceptlowflowyears(Harza-Ebasco1984b).Spawninghabitatisnotspecificallyconsideredintheestablishmentofminimumandmaximummainstemdischargeconstraints.TheminimumdischargeconstraintforCaseEVIislargerinthewintermonthsandsmallerinthesummermonthsthanundernatural.~onditions(Figure16).Themaximumconstraineddischargeisgreaterthanthemeanmonthlynaturaldischargethroughouttheyear(Figure16).ThesimulatedmeanmonthlydischargesforCaseEVI(Figure17)areconsiderablygreaterthantheminimumconstraineddischarge.Theconstrainingboundsrepresentdischargeswhichcouldbereachedduringloworhighflowyears.UnderCaseEVI,minimumflowsduringthecriticalperiodofchumsalmonmigrationandspawninginAugustandSeptemberwillbeincreasedabovetheCaseP-1projectedflowsof6,000cfsto9,000cfs.ForSloughs9and11,amainstemdischargeincreasefrom6,000cfsto9,000cfsisestimatedtoincreasesloughflowby1cfsovertheformer,basedoncurrentlyavailableanalyses(APA1984).InSloughs8A,9Aand21theCaseEVIflowsareanticipatedtoalsoincreasethelocalflowslightly.41 ~-.J~-.-,--'-,.-J-,-,--,~-,.-JoJ"JCl'-..,....~to~f/]~Thehighermainstemflowswillincreasethedischargeinthesloughsthroughincreasedgroundwatercontributionstolocalflow.Thiswillincreasefishpassageefficiency.ThelocalflowswillbelowerthanlocalflowsundernaturalconditionsintheAugusttoSeptemberperiod.Thefrequencyofpassagewillbecomelessthanthenaturalfrequencyofpassage.ThehigherCaseEVIflowswillhaveanegligibleeffectonthebackwateratthesloughmouthsandtheflowswillnotbehighenoughtobreachthesloughsofprimaryimportancetofishproduction(Sloughs8A,9,9A,11and21).CaseEVImainstemdischargesarelessthanthenaturaldischargesduringthesummerandfall.Thelackofbreachingflowsandbackwatereffectswillstilllowertheefficiencyoffishpassageinsloughs"Localflowinthesloughswillalsobelowerthannaturalconditions.CaseEVIwillpartiallymitigateforimpactsonchumsalmonandwillminimizeimpactsonchinookrearinghabitat,nevertheless,adverseimpactsonsidesloughspawningandincubationwilloccur.Mitigationinadditiontoflowreleasewillbenecessaryforthelatesummer,fall,andwinter.oJ--"--'.J..J-'''',"~3.2.2-HabitatModification(a)ImpactIssueResidualimpactstotheamountofspawningandincubationhabitatavailabletochumsalmoninsloughsandsidechannelsofthemiddleSusitnaRiverwillremainafterimpementationoftheCaseEVIorCaseEVflowrelease•Partialorcompletelossofthesehabitats,whencomparedwithnaturalconditions,willresultfrom:42 i"""""""'1[r""MI--"nI'~[[c-'"LJ[[[["L•Reducedbackwatereffects•Reducedfrequencyofbreachingflows•Reducedupwellingduringspawningandincubation•Passagerestriction•Increasedfrequencyofwinterovertopping(b)MitigationMeasuresAnumberofmitigationmeasuresarepresentedinthissectionthatcanbeusedsinglyorincombinationtominimizeidentified.impacts.Table15showstherelationshipbetweenthemitigationmeasuresandtheimpactforwhichtheyaredesigned.(i)ChannelWidthModificationsChannelingsloughflowwillimprovefishaccessthroughpassagereachesbycontractingthewidthofthechannelanddeepeningthechannel.Thistechniqueisespeciallyusefulinmitigatingshort,widepassagereaches.Wingdeflectorsextendingoutfromthechannelbankorrockgabionsrestructuringthecrosssectionofthenaturalchannelmaybeused-tocontracttheflowwidth(Bell1973).Indeterminingthemodifiedwidthforthechannel,amaximumvelocitycriteriaof8fpswasusedto.permitfishaccessthrough-thereach.(Bell1973).-WingDeflectorsWingdeflectorsareusedtodiverttheflowinachanneLTwowingdeflectorsplacedonoppositebankswillfunneltheflowfromawidertoanarrowercrosssectionasshowninFigure18.Thenarrowedchannelisdesignedtoprovidefish43 ~-..,--.~--.-l~~1l-'..-J.,........J~-"_J--"-'~----'passageattheminimumflow.Athigherflows,thewingdeflectorsareinundated;fillbetweenthebanksandthewingdeflectorwallsissizedtopreventscouringathigherdischarges.Fillwilltypicallybecomposedoflargecobblesavailableatthesloughs.Wingdeflectorwallsareconstructedeitherofrockorgabionsformedofwiremeshandfilledwithcobbles.Anotheralternativeistheuseof12-inch-diametertimbers,anchoredtothebanksandchannelbed.Awingdeflector·costs$31,000whenconstructedofrock,approximately$24,000whenconstructedwithgabions,and$22,400iftimberlogsavailableonsiteareused.Forsiteswheretimberisnotavailable,alogwingdeflectorwouldcost$23,200.EstimatesarebasedonatypicalpassagereachforasloughonthemiddleSusitnaRiver(Figure19).-RockGabionChannelReshapingtheoriginalcrosssectionofthechannelwithrockgabionsisanalternativemethodofchannelizingthesloughflow.Thechannelisexcavatedandgabionsareusedtoestablishthenewconfiguration.Thenewchannelshapeisdesignedtomaximizedepthatminimumflows;athigherdischarges,thegabionspreventscouringofthechannelbanks.Figure20illustratesatypicalcrosssectionforareshapedpassagereach.Forlongpassagereaches,restingareasarecreatedbywideningthechannelbetweentherockgabionsformingtheminimumdischargechannel.Thegabionsareprovidedthroughoutthelengthofthepassagereachandprotectedupstream44. -.---'......-~--.'--'-~-..,..J.,.,-.J.,;.J--"~J_..i~-OJ-"--"dbyripraporwingwallgabions.Thegabionbanksextendhigherthantheheightofthemaximumsloughdischargetopreventcollapsefromerosion.Thegabionscomposingthechannelbankspreventscouringofthebanks;thechannelwillbemorestablethanasimilarchannelmodifiedbywingdeflectors.Forpassagereacheswithgreatlyvaryingdischarges,theaddedstabilityoftherockgabionchannelisanadvantage.Thecostofconstructingthegabionchannelisapproximately$60,000foratypicalpassagereach.(ii)ChannelBarriersF~shaccessthroughpassagereachesisalsoimprovedbycreatingaseriesofpools.Barriersareplacedtobreaktheflowonlong,steeppassagereachesandcreatepoolsbetweenobstacles.Fishpassageovertheobstaclesisaccomplishedifsufficientstepsofdecreasedbarrierheightareprovidedtopermitsurmountingtheoriginalbarrier(Bell1973).Channelbarriersareusedonlongslopestocreatefishrestingpools,asshowninFigure21.Thesebarrierswithheightsof10inchesto14inchesactasweirs,withasectionofdecreasedheighttoimprovefishpassagebetweC?npools.Thebarriersareconstructedofvariousmaterials.Concretehighwaycurbsanchoredtothebedwithrebar(Figure21)orcobblesandbouldersplacedtocreateasillmaybeused.Logsmayalsobeattachedtothebanksandanchoredsecurelytothebedtopreventmovementathighdischarges.GabionsshapedasshowninFigure21mayalsobeused(Listeretal.1980b).45 PassageProvidedbyFlowAugmentation46Channelsareconstrainedinwidth.toformeffectivepools.Forawidechannel,channelwidthsaremodifiedwhereapoolandweirstructureisdesired.Thesloughsofprimaryinterest,including8A,9,9A,11,and21,·wereconsideredinevaluatingthefaasibi1ityofapipingsystematamainstemdischarge0f9,000cfs •ThiscorrespondstotheminimumspawningperiodmainstemdischargeforCaseCost/Barrier$12,000$16,000$12,000$11,000$12,000BarrierConcretehighwaycurbsRocksillGabionsAnchoredlogsavailableonsiteAnchoredlogsnotavailableonsiteEstimatesofcostsperbarrieronthebasisofatwobarriersystemarelistedbelow.Eachslopewillrequiremorethanonebarriertocreateaseriesofpools.Asmorebarriersarebuiltonasite,thecostperbarrierwilldecreasebecauseoftheeconomiesofscale;themajorcostinvolvedintheconstructionofthebarrieristhe.costoftransportingtheequipmentneeded.Withlowermainstemdischarges,lessgroundwatermaypercolateintothesloughs,resultingindecreasedsloughdischa,rge(APA1984).Passagereachesnegotiableatnaturalflowsmightbecomeimpassableunderprojectconditions.Inordertoaugmentthesloughflow,apipingsystemcanbedesignedtotransportwaterfromthemainstemorothersourcestoaffectedpassagereaches.(iii)[l~[[[[[[[[[[[[[[[r~ -,->;)....."__J-"1\___J---"..,...."._,-"~-"--'-,--'j-,.-'--,-~-,---J----.;iJ,-"'"J"--''-'ILJuEVIflows.Thesystemfeasibilitywasalsoconsideredatamainstemdischargeof12,000cfscorrespondingtotheminimumdischargeforCaseEVduringtheAugusttoSeptemberperiod.ForSloughs8Aand9A,themainstemelevationsat9,000and12,000cfswouldproduceinsufficientheadbetweenthemainstemstageandthecriticalpassagereachestoprovidesufficientflowtoprovidepassage.Flowscorrespondingtothesite-specificovertoppingdischargesarenecessarytoproducetherequiredheadfortherequiredflow.AtSlough9,a9,000cfsmainstemdischargewouldprovidesufficientheadfor1cfsthroughapipedsystem.Acollectiontank(Figure22)20feetfromthemainchannelwouldcollectmainstemwater.Thecollectorwasdesignedtobelocated20feetfromthemainsteminordertoprovideerosionprotectionandafiltrationsystemforthewater.A1-foot-diametercorrugatedmetalpipewoulddeliverthewater2,800feettotheupstreamendofPassageReach(PR)V,asshowninFigure23.Atamainstemdischargeof17,000cfs,thesystemwouldprovideapproximately1.5cfs.Thesystemwouldprovideamaximumof3cfspriortobermovertopping.TheamountofflowprovidedbythesystemseemstobeuneconomicalwhenthealternativeoptionsavailableatSlough9areconsidered.Theinstallationofapipingsystemisnotrecommendedduetothehighcostofthesystemandthelargenumberofmitigativemeasuresfeasible.ForSloughII,mainstemdischargesof9,000cfsor12,000cfscouldprovidesufficientheadforaflowof1cfsfromacollectorthrougha1-foot-diameter47 c..-,-'~1'''"''1~--"""""'l--1-,./;,;)_.....J~..~-,J::;'."1J-,-;j-Ji~=-"pipefordeliverytoPRV,adistanceof3,200feetfromthesloughhead(Figure24).TheinstallationofapipingsystemintoSlough11isnotrecommended;thequantityofwatersuppliedislow.Alternativemitigationoptionsexistwhichcouldaccomplishasimilarreductioninnegativeimpactswithreducedmonetarycosts.Amainstemdischargeof9,000cfswouldbenecessaryatSlough21foralocalflowof1cfsfromasimilarsizedcollectorthrougha1,700~foot-Iong,0.75-foot-diameterpipe(Figure25).Amainstemdischargeof12,000cfswillnotsignificantlyincreasetheflowthroughthesystem.Amaximumof2cfswouldflowthroughthesystemjustpriortoovertopping.Theshorterdistancefromthemaintemtothepipeoutletandthesmallerpiperequiredinthesystemincreasedesirabilityoftheinstallationofsuchasystem.TheadditionoflocalflowwillincreasethefrequencyofpassageandimprovespawninghabitatthroughoutSlough21andSideChannel21.Estimatedconstructioncoststotal$120,000forthebackhoeinstallationofthecollectorandpipingsystemin-Slough9,$120,000forthesysteminSlough11and$134,000forthesysteminSlough21..(iv)UpwellingAugmentationAsystemprovidingsupplementaryupwellingwouldmaintainorincreasespawninghabitatinthesloughsduringlowmainstemdischarges.Themainstemandnearbytributarieswereevaluatedaspossiblesourcesofupwellingwater.Themainstemasan48 [[[[[[[[[[[[~[[[[[f"Lupwellingwatersourcecouldnotbeusedatnumeroussitesbecauseofthelowhydraulicheadatlowmainstemflows.Forsloughswithtributaries,thetributarycouldprovidethewaterandthehydraulicheadforanupwellingsystem,asshowninFigure26.Thecriticalperiodforinducedupwellingwouldbeduringtheproject'sprojectedlowmainstemd:i,schargeperiodinAugustandSeptember.Undernaturalconditions,itisassumed,basedontherelationshipsprovidedinAPA(1984),thatupwellingincreasesduringthisperiodbecauseofthehighmainstemdischarges.Selectionofspawningsiteshasbeenshowntoberelatedtothepresenceofupwellingatasite;therefore,upwellingneedstobemaintainedunderprojectflowstomaintainspawninghabitat.Undernaturalconditions,themainstemstageandupwellingdecreasefromSeptemberuntiliceformationinNovembertoDecember.Similarly,atributarysuppliedupwellingsystemwouldalsohavedecreasingdischargesduringthisperiod.Reduction_inapipedwatersupplywouldnotbecome~ignificantuntilmid-October,whenprojectdischargesincrease.UpwellingunderprojectoperationislikelytobegreaterthanupwellingundernaturalconditionsfromSeptembertoDecember.Upwellingduringwinter(DecembertoMarch)willdecreaseforsloughsupstreamoftheicecoverandincreaseforsloughsdownstreamoftheicefront,relativetothenaturalconditions.49 [[f."._-"[[[[-.>[[[[[-'.~[[[[[[LInthespring,tributaryflowsincreasewiththemeltingofsnowandice.ByApril,thetributaryflowswouldbesufficienttoprovideupwellingfromthepipingsystem.Upwellingthuswouldbeprovidedcontinuouslythroughouttheyear.Undernaturalconditions,upwellingisgreatestfromJunethroughSeptemberandDecemberthroughApril.Temperaturesoftheupwellingflowsfromthepipedsystemwouldcorrespondtothetemperaturesofthetributaryf~ows.WaterwillflowthroughthesystemaslongasthewatertemperaturesareaboveO°C.Freezingwaterwillnotbereleasedinthespawninggravels,asflowwillceaseinthesystematfreezingtemperatures.Estimatedcostofthesystemis$210,000fora300-footmain.pipeand200-footreachesofcrosspipe,spacedat5-footintervalsforupwelling.AsystemwithalongermainpipecouldbebuilttotapGoldCreekwaterforSlough11.Untilmorerefinedvaluesareavailablequantifyingtheextentofthereductioninupwelling,thesystemwillnotberecommendedforinstallationinanyslough.(v)SloughExcavationMechanicalexcavationofcertainreachesofsloughswouldimprovefishaccessandfishhabitatwithinthesloughs.Atsloughmouths,excavationwouldprovidefishaccesswhenbackwatersarenegligibleduringlowmainstemdischarges.Mechanicalexcavationcanbeusedtofacilitatepassagewithinsloughsbychannelizingtheflowordeepeningthethalwegprofileatthepassagereach.50 ~-,""'-'-,--i-,-'1-,r.....~--,d1"'1ur-",;,-"L.#-~(vi)Onalargerscale,mechanicalexcavationtolowertheprofileoftheentiresloughcouldincreasetheamountofupwellingintheslough.Agreaterheadbetweenthemainstemandthesloughbedwouldresultinadditionallocalflowintheslough.Anadditionalbenefitoftheexcavationprocesswouldbetheopportunitytoimprovethesubstrateintheslough.Replacementofpoorsubstratewithsuita~lespawninggravelswouldprovideadditionalspawninghabitat.Sortingoftheexistingsubstratewillbeundertakentoremoveunsuitable·particlesizes.Theexcavationprocesswouldbedesignedtodevelopadditionalspawningandrearinghabitat.AnestimateoftqecosttoexcavateatypicalsloughmouthinthemiddleportionoftheSusitnaRiveris$26,000.Anestimateofthecosttoloweratypicalsloughprofileby2feetforalengthof2,000feetinthemiddlesectionoftheSusitnaRiveris$34,000.DevelopmentofNewSpawningHabitatInordertoprovidetheconditionsthatchumsalmonpreferforspawning,existingpoolsinsloughswouldbemodified.Chumsalmonprefertospawnatupwellingsites(ADF&G1983a).Aweirstructurethatispermeableatthebaseandimpermeableelsewherecouldbeerectedinapooltoproduceaheaddifferencebetweentheupstreamanddownstreamsides.Suchaweirwouldcausewatertoflowthroughthespawninggravelsplacedatthebaseofthestructure(Figure27).51 -".--j~'-~1J--"'4-.,.-.J--i"-.-il~JAnotchinthetopofthestructurefacilitatesfishpassagebetweenpools.Thenotchisdesignedforaminimumsloughdischargeof2cfs;thisdischargecorrespondstoatypicallowdischargeinthesloughsalongthemiddlesectionoftheSusitnaRiver.Thestructureissecurelyembedded,anchoredtothechannelwallsandbed,andriprappedtopreventerosionduringhighflows.Theweircanbeconstructedoftimberposts10inchesindiameter,reinforcedwith2 x 4inchcrossbracingandfacedwithimpermeablematerial,asinFigure28.Gravelmaterialsarepiledoneachsideoftheweir;thegravelprovidesstabilitytothestructureinadditiontoprovidingspawninghabitat.Onlyfinesiltspresentinthegravelbasewillbeerodedbythe2fpswatervelocitiesovertheweir.Thespawninggravelswouldhaveamaximumangleof10°withthechannelbedtopreventdownstreamdisplacementcausedbyfemalesdiggingreddsduringspawning.RockgabionscanalsobeusedtoconstructtheweirshowninFigure29.Sheetsofplywoodinthecenterofthestructureimpedeflowthroughthegabions.Spawninggravelsprovidehabitatatthebaseofthestructure.Anotchisprovidedforfishpassageatlowflows.ArockstructurewithanimpermeablecorecanbebuiltasinFigure30.Plywoodsheetsanchoredwithreinforcingrebarsareadequateforuseasacore.52 .,..--.:.j,Thedecisionastothematerialsusedfortheweirstructurewillbemadeduringthedesignphaseoftheprojectbasedonthecost,durability,andaestheticsofthevariousstructures.Thecostestimateofthethreestructuresisbasedona20-footchannelwidthanda3-footnaturalpooldepth.Economiesofscaleareconsiderableifmorethanonestructureisbuiltatasite.--"-,JJJStructureTimberpileweirRockgabionweirRockweir(vii)PreventionofSloughOvertoppingCost/Weir$32,000$32,000$45,000/-"'I-'~,j--'""-,--'J-ii~.J..4Projectflows~rehigherthannaturaldischargesinthewinter.Icestagingatthesedischargeswillresultinanincreaseinmainstemstageandincreasetheprobabilityofovertoppingofsloughsdownstreamoftheicecoverfront.AninfluxofcoldmainstemwaterintotheincubatingareaoftheSlough8Ain1982causedhighembryomortality(ADF&G1983b).Topreventovertopping,theheightofthesloughbermsisincreasedasshowninFigure31.Costestimatesperbermtotal$150,000initiallyand$7,500averageyearlymaintenance.Maintenancemayberequiredin3to5yearintervals.53 (c)SiteSpecificImpactsandMitigationsSite-specifichabitatmodificationmeasuresareproposedforSloughs8A,9,9A,11and21andSideChannels11and21.Collectively,themeanpeakspawningcountstothesesitescomprised72percentofthemeantotalpeakcountstosloughsfor1981,1982,and1983(ADF&G1984a).ThemodificationtechniquessuggestedfortheseselectedsitesareapplicabletotheremainingsloughssupportingspawningchumsalmoninthemiddleSusitnaRiver.CostestimatesforthesesitesaresummarizedinTable16.(i)Slough8ADuringthe1981-1983studies,themeanpeakcountsofchumsalmonandsockeyesalmoninSlough8Awere331(range:37-620)and104(range:67-177).Themeanestimatedtotalescapementstothesloughwere553chum(range:112-1062)and152sockeye(range:131-195)(ADF&G1984a).Slough8Ameanescapementscomprised15.7percentofthetotalescapementtosloughsinthemiddleSusitnaRiver.Theapproximatepercentagedistributionofchumsalmonduringthe1984spawningseasonisshowninFigure32.-ImpactIssue•BackwaterSpawninghabitatthatisdependentonbackwatereffectsforprovidingsuitablespawningdepthswouldbe.lostbecauseofprojecteffects.Anestimatedspawningareaof103,000squarefeetisaffectedbythebackwaterzoneofnaturalflows.Theportionofthisareawouldbecome54 [[[[[[~...,I.Iu~--..J-~--'c..J~~1-'L.>unsuitableforspawningatCaseVIprojectflowswouldbegreaterthanthatoftheCaseVflows•BreachingTheexceedenceprobabilitiesassociatedwithnaturalbreachingflows27,000and33,000cfsare7percentforthenorthwestchanneland2percentforthenortheastchannel.Theserelativelylowprobabilitiesindicatethattheimportanceofbreachingliesinprovidingsuccessfulpassageratherthanincreasingthepotentialspawninghabitatbyincreasingtheareawithsuitablespawningdepths.NeithertheCaseEVIorCaseEVprojectflowswouldbeofsufficientmagnitudetoprovidebreachingconditions.•GroundwaterUpwellingCaseEVIwouldreducegroundwaterupwellingby50to62percentduringthespawningseason.CaseEVreductionswouldamountto29to50percent.•WinterFlowsOvertoppingofSlough8Aispredictedforseveralcombinationsofyearspecificclimatologicdata,operationalregimes,anddemandschedules(Harza-Ebasco1984a).•PassageRestrictionsUnderCaseEVIflows,thefrequencyofsuccessfulpassageconditionswilldecreaseat55 -.--"<"'"""11;.-.-"~~...",-J-,--'~--'!--',~-,--',-i.,--'__,i.....J--,....-.3.......Jpassagereaches(PR's)IandIIfromnaturallevelsof79and48percenttoprojectlevelsof25and16percent.ForPR'sIIItoIXthedecreasewillrangefrom1to3percent(Table17).CaseVflowswouldincreasethefrequencyofsuccessfulpassageabovenaturalconditionsin100percehtofPRI.AtPRIIadecresewilloccurfrom48to18percent.AttheremainingPR's,decreaseswouldbe1or2percent.The18,000cfsspikeproposedforCaseEVwouldtemporarilyprovidefrequenciesofsuccessfulpassagegreaterthanthoseundernaturalconditions.Thesedecreasesinfrequenciesofsuccessfulpassagemay,overtime,resultinalossofpotentialspawninghabitat.HistoricallyspawnedareasarepresentedinTable7.-MitigationPassagethroughPR'sIandIIisprovidedundernaturalconditionsbybackwatereffectsfromahighmainstemdischarge.WithCaseEVIflows,accessthroughthesep~ssagereacheswillbeprovidedinanalternativemannertomaintainthe103,000squarefeetfishhabitatavailablewithintheslough.BenefitsthatmayaccruefromtheCaseV18,000cfsspikewoulddependonitsoccurrencerelationtoescapementtimingandotherconditionscontributingfactorstofrequencyofpassage.ThemaximumchannelbedelevationofthePRIwillbereducedtoeasefishpassageintotheslough•FlowinPRIIwillbechanneledtoincreasethedepthattheexpectedlowersloughflow.Adding56 .-"wingdeflectorstonarrowthechannelandremovebouldersfromthechannelwillimprovepassagethroughPRII.Otherpassagereachesmaybeimprovedbyexcavatingadeeperchannelthroughthereach.~~~i~"'-'WinterovertoppingoccursatSlough8Aundernaturalconditions(R&MConsultants1983).UnderCaseEVI,thefrequencyofwinterovertoppingispredictedtoincrease(Harza-Ebasco1984a).Increasingtheelevationofthebermattheheadofeachforkofthesloughwillpreventovertoppingbynear-freezingwaters.Theheightoftheeastforkbermwillbeincreasedby9feet;approximately250feetofbermisrequired.Thewestforkbermwillbeincreasedfourfeetforalengthof250feet•.....,_.Jr~I-'ThecostsassociatedwitheachofthemitigationmeasuresforSlough8AareshownbelowandinFigure32:.-,I---,Miti2ationMeasureNumberPro,eosedCapitalCostsAnnualOperating&Maint.CostsJ5,0001,500\2,000\15,000_/~,/$23,50~/L':c·..~~26,00024,00010,000295,000$355,000TotalSloughmouthexcavation1Wingdeflector1Excavatepassagereaches6Protectivesloughberms2-"J~~_.f/.J(ii)Slough9-.-3'-"Duringthe1981-1983studies,themeanpeakcountsofchumsalmonandsockeyesalmoninSlough9(including9B)were295(range:175-358)and33l-,;,...)57J ~r-,--""1-~~----:-;..J'-......:WI(range:2-91).Themeanestimatedtotalescapementstothesloughwere563chum(range:430-645)and81sockeye(range:0-230)(ADF&G1984a).Slough9meanescapementscomprised11.6percentofthetotalmeanescapementtosloughsinthemiddleSusitnaRiver.Theapproximatepercentagedistributionofchumsalmonduringthe1984spawningseasonisinFigure33.-ImpactIssue•BackwaterBackwatereffectsprovidedpotentialspawning.areaduringthestudyperiod1982-1984andonly).asmallportionofthatareawasspawnedonlyin1983.Thelowerportionofthissloughhassincesiltedinandthechannelhaschangeditscourse,thusprecludingspawning·inthisarea.'•BreachingTheexceedanceprobabilityassociatedwithbreachingdischargesof19,000cfsis29percent.Itisprobablethatthebreachingflowsareprovidingthedepthrequiredforspawninginsomeareasandthattheseareaswouldbecomeunspawnableatproje~tflows.However,theextentoftheseareasappearminimalwhenthewettedperimeterboundariesataflowof9,000cfsareoverlaidonoutlinesofspawnedareasfrom1982-1984.NeitherCaseEVnorCaseVprojectflowswouldbeofsufficientmagnitudetoprovidebreachingconditions.58 """"-.-,,----,-.,,---'---'.J----,--J-,,---'-'--.",~-'---"•ReducedGroundwaterUpwellingCaseEVIwouldreducegroundwaterupwellingbyapproximately40percentduringthespawningseason.CaseEVreductionswouldamounttoapproximately20percent.•WinterFlowsTheupstreamextentoftheicecoverisprojectedtoprogressbeyondSlough9forseveralcombinationsofselectedmeteorologicdata,operationregimes,anddemandschedules.Basedonthesimulationscompletedtodate,thereisamoderateprobabilityofannualovertoppingoftheslough(Harza-Ebasco1984a).•PassageRestrictionsBasedonmainstemdischarge-groundwaterrelationshipsthesloughflowanalysisinWCC(1984),CaseEVIflowswillresult-inreductionsinthefrequencyofsuccessfulpassageconditionsatPR'sI,III,IVandV.SuccessfulpassageatPRIwouldbereducedfrom100to47percent.AtPR'sIIIandIV,passageundernaturalconditionsoccurs18and17percentofthetimeascomparedto15percentand14percentunderprojectflows(Table18).AtPRV,naturaloccurrencesof29percentwillchangeto0percentpassageunderprojectflows.ThereductioninopportunitiesinpassageatPR'sIIIandIVmayalsoresultinlossofsomespawninghabitat.CaseVflowswouldresultindecreasesofsuccessfulPRIIIandIVofonly1to2percentanddecreasesfrom29tono59 ---..,,,-"''1--",->-,j,-..oJ-,J-,.j~~-..J'-".J-,-..J--"~,~.J>passageatPRV.ThegeneralareaofspawningabovePRVthatwould.becomeinaccessibleatCaseEVIandCaseVflowsamountstoapproxi-mately5,300squarefeet(Table8).-MitigationPassagethroughthedownstreamsectionofSlough9iscurrentlydifficultbecauseofsiltdepositedduringthe1983-1984season.Removalof,thissiltwillexposethespawninggravelsandincreasethehabitatinthedownstreamregionoftheslough.ThesloughmouthwouldbeexcavatedtoincreasethefrequencyofpassagethroughPRIundertheCaseEVIflowregime.BasedontherelationshipbetweenmainstemflowandsloughflowpresentedinAPA(1984),PR'sIIIandIVaregreatlyaffectedbyareductioninnaturaldischarges.AtdischargescorrespondingtoCaseEVIthefrequencyofpassagethroughthesereacheswillbeincreasedbyexcavatingadeeperchannelandchannelizingtheavailablelocalflow.Largercobblesandboulderswillberemovedfromthe'channeltoimprovethespawninghabitat.OthereffortstoimprovespawninghabitatinthepoolregionbetweenPR'sIVandVincludeconstructionofarockweirtoincreaseavailablespawninghabitat.UpstreamfromPRV,spawninghabitatisavailableundernaturalconditions.Underprojectconditions,basedonthecurrentlyavailablesloughflowanalysis,fishwouldnotbeablereachthishabitat.Apoolandweirstructurewillbeconstructedtoenablefishtoaccessthenatural60 -,1,->-,-,,,poolhabitatavailableupstreamofPRV.Aseriesof20weirscomposedofanchoredlogswillallowsalmontoaccessanadditional1,000ftofSlough9.Slough9isexpectedtobeovertoppedmorefrequentlyinwinterbytheincreasedicestagecausedbyprojectflows(Harza-Ebasco1984a).Anovertopping-preventionberm8feethighand375feetlongwillbeplacedattheheadofthesloughtomaintainthesuitabilityofincubationhabitatwithintheslough.ThecostsassociatedwitheachofthemitigationmeasuresforSlough9areshownbelowandinFigure33:,-0'Miti2ationMeasureNumberPr0,e.osedCapitalCostsAnnualOperating&Maint.Costs_-1,-"'I.J--,Sloughmouthexcavation1Rockweir1Protectivesloughberm1Logbarriers20Passa2ereachexcavation2Total(iii)Slough9A26,00037,000150,00030,0007z.000$250,0005,0003,0007,5006,0001z.000$22,500-0'-3i-'J.JDuringthe1981-1983studies,themeanpeakcountofchumsalmoninSlough9Awas135(range:105-182)whilethemeanestimatedtotalescapementtothesloughwas152chum(range86-231)(ADF&G1984a).Slough9Ameanescapementcomprised6.4percentofthetotalescapementtosloughsinthemiddleSusitnaRiver.Theapproximatepercentagedistributionofchumsalmonduringthe1984spawningseasonisshowninFigure34.61 --,--)~~-ImpactIssueBackwater,.,.,Evaluationofbackwatereffectsarenot--~applicableconditionstothisprevailsloughforthebecausebreachingmajorityoftheThebreachingdischargeforSlough9Ahasnotbeenestablishedbutappearstobearound12,000cfs,exceedanceprobabilityof71percent.FieldobservationsduringSeptember1984indicatedthatthegravelsurfaceofsomeareasspawnedearlierintheseasonunder..J".-J.''1_..J--"..J1.J,spawningseason••Breachingbreachedconditionsweredewatered.Survival..J----,_J---,-.J"•..J,-'~JJ~~fromtheseareasisunknown.EstimatesofthespawningarealostunderCaseEVIwillbeobtainedbyoverlayingtheboundariesofthewettedsurfaceareaat9,000cfsontothespawnedareasdelineatedforthe1982-1984seasons.Thebaseflowof12,000cfsforCaseYmayprovidebreachingflowsandflowspikeof18,000cfsmostcertainlywould.•GroundwaterUpwellingCaseEVIwillreducegroundwaterupwellingby30-48percentduringthespawningseason.CaseEVreductionswillrangefrom13-24percent.•WinterFlowsSimulationoftheupstreamextentoficecoverforseveralcombinationsofoperatingregimes,62 "...."-,-,-,-'---,-~_2---,---,--"---,._~1.-.J,---'----,-.J........Jdemandschedulesandmeteorologicconditionsforselectedyearsindicatedthatthereisaprobabilityofthesloughovertoppingonanannualbasis(Harza-Ebasco1984a).•PassageRestrictionsUndernaturalconditions,PR'sI-IX·canbesuccessfullynegotiatedbychumsalmon-100percentofthetime(Tabl,e19).Fiveoutoftheseninepassagereachesareanticipatedtoprovidesuccessfulpassagecondition3to32percentofthetimeunderCaseEVIflows.Ofthefivepassagereaches,PRIIIisconsideredtobeofgreatestconcernsinceaccesstosubstantialamountsofhistoricallyspawn~dareascanbeachievedifpassagethroughthisreachisfacilitated(Table9).BreachingconditionsresultingfromCaseEVflowswouldprovidepassage100percentofthetime.-MitigationSpawninghabitatinSlough9Aisprimarilyaccessedduringbreachingflows·undernaturalconditions.UnderCaseEVIscheduleddischarges,thehabitatwillberetainedbylowering-thesloughprofileuntildepthssuitableforspawningareobtained.Whilethesloughprofileisbeingexcavated,thelargecobblesandboulderswillbesortedandremovedtoimproveaccessbetweentheseriesofpoolsthatexistalongthethalweg.Removalofthelargecobblesandboulderswillprovideadditionalspawninghabitattothatpresentlyexistingwithinthesidechannels.63v 64ThecostsassociatedwitheachofthemitigationmeasuresforSlough9AareshownbelowandinFigure34:Slough9Abreachesatarelativelylownaturalmainstemdischargeandprotectionfromwinterovertoppingunderprojectconditionswillbesupplied.Thebermattheheadofthesloughwillbeheightened10feetforalengthof150feettopreventwinterovertoppingiftheicefrontispredictedtoextendupstreamofthissloughmorefrequentlythanonceeverytenyears.Duringthe1981-1983studies,themeanpeakcountsofchumsalmonandsockeyesalmoninSlough11were369(range:238-459)and532(range:248-893).Themeanestimatedtotalescapementstothesloughwere957chum(range:674-1119)and1128sockeye(range:564-1620)(ADF&G1984a).Slough11andUpperSideChannel11meanescapementcomprised17.6percentofthetotalescapementtosloughsinthemiddleSusitnaRiver.Theapproximatepercentagedistributionofchumsalmonduringthe1984spawningseasonforSlough11andUpperSideChannel11isshowninFigure35.\...-'$7,50051000$12,500AnnualOperating&Maint.CostsCapitalCosts$150,000761000$226,000NumberProeosedTotalMiti2ationMeasureProtectivesloughbermExcavationofslou2hSlough11(iv)[[[[r''-....J;![[[r~L)[[[[[[[[[[ .,......~.-'",==",'.J'-'-~1-,...J-',--i~~!oJJ......~~J•...i1-ImpactIssue•BackwaterThebackwateratthesloughmouthaffectsapproximately50,000squarefeetofareathathasbeenspawnedinthepast.Overlyingtheboundariesofthewettedsurfaceareaat9,000cfsindicatesthatapproximately20percentofthatspawnedareawouldbedewateredduringCaseVIoperations.LesshabitatwouldbelostunderCaseVflows.Forpurposesofmitigation,thisdewateredareawillbeconsideredlosthabitat.Additionalhabitatwiththewettedperimeterat9,000cfsmaybeunsuitableforspawningduetoinsufficientdepthandwouldalsobeconsideredlosthabitat••Breaching-Theexceedanceprobabilitiesassociatedwithnaturalbreachingdischargesof43,000cfsisonepercent.Basedonthislowfrequencyofoccurrence,thecontributionofbreachingconditionsinprovidingaccessandpassageorinincreasingthespawnableareawithinthesloughisnegligible.NeitherCaseEVI,CaseCorCaseEVwouldprovidebreachingflows.•GroundwaterUpwellingCaseEVIwillreducegroundwaterupwellingby20-25percentduringthespawningseason.CorrespondingreductionsforCaseEVrangefrom13-19percent.65 l"",_CJl--"--"--"-"~uu-"•WinterFlowsSimulationsoficecoverprogressinghaveindicatedthatthefrontwillproceedasfarasSlough11generallyinthecoldestyears(Harza-Ebasco1984a).Theprobabilityofthesloughovertoppingonayearlybasisisthereforelow.•RestrictedAccessUndernaturalconditions,PR'sI-IIIprovidesuccessfulpassage70,43and12percentofthetime,principallythroughthegroundwatercontributiontolocalsloughflow(Table20).PassagereachesIVandVprovideadequatepassageconditionsonlyduringinfrequentbreachingconditions,whichoccuronepercentofthetime.Basedoncurrentlyavailableinformation,projectflowsof9,000cfswillreducethegroundwaterinputtotheextentthatpassagewillberestrictedacrossallpassagereaches(APA1984).CaseVflowswillprovideadditionalgroundwatertothesloughandresultinfrequenciesofpassageforPRI,IIandIIIof60,20,and5percent.TheCaseEVspikewouldbeofsuchshortdurationthatcontributionstogroundwaterwouldbeminimaLThespawningareasthatwillbeaffectedareshowninTable10.-MitigationThepassagereachesinSlough11willrequirechannelizationinordertoincreasethedepthofflowinthereachesandprovidepassage.66 .,.-.,.,-.-.,.J~-.,-J...---,-".J-'Achannelwillbeexcavatedthroughthesiltymaterialsatthesloughmouthandthebanksofthechannelstabilizedwithrockgabions.Thestabilizedchannelwillextend1,200feetupstreaminthesloughandmodifyPR'sIandII.PassagethroughPRIIIwillbefacilitatedbyconstructionofwingdeflectorsmadefromrockgabions.AchannelwillbeexcavatedatPRIV.Apoolandweirstructurewillbeconstructedintheexcavatedchannelwhichwillimprovefishpassageupstream.Fifteenweirswillbeneededfor300feetofsloughchannel.Undernaturalflows,backwatereffectsprovide_50,000squarefeetoffishspawninghabitatatthesloughmouth.Underprojectconditions,thisspawningareawillbepartiallyreplacedwithrockweirsplacedinpoolsbetweenPR'sIIandIIIandPR'sIIIandIV.Underprojectconditionsthesloughmayexperiencewinterovertopping.Iffurtheranalysisoficeprocessesindicatesahighfrequencyofovertopping,thebermattheheadofthesloughwillbeheightenedfivefeetforalengthof250feettopreventthisoccurrence.ThecostsassociatedwitheachofthemitigationmeasuresforSlough11areshownbelowandinFigure35:67 ~--"AnnualNumberCapitalOperating&MitigationMeasureProposedCostsMaint.CostsWeirs261,0006,000Bankstabilization125,0003,000Sloughexcavation126,0005,000Logbarriers1524,0005,000Protectiveberm11500007500Totall$286,000\$26,500,..,-,-..J,.J-'-""J-'-"-I(v)UpperSideChannel11-ImpactIssue•BackwaterEffectsThebackwateratthesidechannelmouthaffectsalargeportionoftheareathathasbeenspawnedinthepast.Overlayingtheboundariesofthewettedsurfaceareaat9,000cfsindicatethatdewateringofspawnedareawouldbeminimal.However,thedepthsat9,000cfsmaybeunsuitableforspawning.•BreachingTheexceedanceprobabilityassociatedwiththecontrollingbreachingdischargeof16,000cfsis45percent.Thisrelativelyhighfrequencyofoccurrenceindicatesthatbreachingflowsareinstrumentalinprovidingaccessandpassageandincreasingthespawnableareainthesidechannel.•GroundwaterUpwellingMainstemdischarge-groundwaterupwellingrelationshiphavenotbeendevelopedforthissidechannel.68 ,-'"'-'~,----,---"'---,----'~.--"..-JJc..;.~.J..--Ii•WinterFlowsSimilartoSlough11theprobabilityofthesidechannelovertoppingonayearlybasisislowtomoderate.RestrictedAccessUndernaturalconditionsPR'sI-IIIprovidesuccessfulpassage100,45and45percentofthetime.CaseEVIandVwouldeliminatesuccessfulpassageconditionsatallthePRs,principallythroughreductioninbreachingflows(Table21)..HistoricallyspawnedareathatwouldbelostareshowninFigure11.MitigationThemajorityofthespawningareainthissidechanneloccursbelowPRIandmuchofthiscouldberetainedunderCaseEVIorEVflows.AccesstospawningareasabovePRIwillrequireexcavationofthechannel.Themeasure,accompaniedwith'replacementofspawninggravelswouldprovidemorespawninghabitatthancurrentlyexists.Preventionofovertoppinginthewinterandduringspringrunoffwillbeaccomplishedbyconstructingabermatthemouthofthesidechannelparalleltotheflow.Thebermwouldbe10feethighand1000feetinlength.ThecostsassociatedwitheachofthemitigationmeasuresforUpperSideChannel11areshownbelowandinFigure35:69 [")c[[NumberMitigationMeasureProposedChannelexcavationProtectivesloughbermTotalCapitalCosts$26,000150,,000$176,000AnnualOperating&Maint.Costs$5,0007,,500$12,500[[[c[r~L;c[C[[[[[J'L-'(vi)Slough21Duringthe1981-1983studies,themeanpeakcountsofchumsalmonandsockeyesalmoninSlough21were443(range:274-736)and96(range38-197).Themeanestimatedtotalescapementstothesloughwere958chum(range:481-1737)and148sockeye(range:63-294)(ADF&G1984a).Slough21andLowerSideCHannel21meanescapementscomprised21.1percentofthetotalescapementtosloughsinthemiddleSusitnaRiver.Theapproximatepercentagedistributionofchumsalmonduringthe1984spawningseasonforSlough21andLowerSideChannel21isshowninFigure36.-ImpactIssue•BackwaterSpawningareasinthemouthofthesloughdonotappeartobedependentonbackwaterandareasthatwerespawnedundernaturalflowsshouldremainspawnableunderCaseEVIandCaseEV.•BreachingTheexceedanceprobababilityassociatedwiththenaturalbreachingdischargeof25,000cfsfortheleftchannelis10percent.Breachingprovidesaccessandpassagewithintheslough,70 -"-,butdoesnotappreciablyincreasearea.NeitherCaseEVInorCaseprovidebreachingconditions.•GroundwaterUpwellingspawnableEVwould~~.-..,,..-J-"--'-,~,-'-..,,_1-,-iI-',-"-'CaseEVIwouldreducegroundwaterupwellingbyapproximately77percentduringthespawningseason.CaseEVreductionswouldbeapproximately38percent.•WinterFlowsTheicefrontispredictedasfarasSlough21onlyduringthecoldestofyears(Harza-Ebasco1984a).Theprobabilityofthesloughovertoppingisverylow.•RestrictedAccessPR'sI,.IlL,andIIRprovidesuitablepassageconditions100,25and20percentof.thetimeundernaturalflow.CaseEVIflowswillreducethefrequencyatPR'sI,IlLandIIRto6,0,an41percent,primarilyasaresultofreducedgroundwaterflow(Table22).ThefrequencyofpassageforCaseVandCaseEVIflowswouldbe100,0,and2percentforPR'sI,IlLandIIR.TherestrictionatPRIlLwilleliminatethespawnableareaabovethispoint(Table12).Ifpassagewerefacilitated,muchofthehistoricallyspawnedareawillnotbeofsufficientdepthforuseunderprojectflows.71 [[[[[[[[[-MitigationPassagethroughSideChannel21isnecessarypriortoentryintoSlough21.MitigationofpassagesreacheswithinLowerSideChannel21isneededtopermitfishaccesstothehabitatinSlough21.PassagethroughSlough21willbeamelioratedbytheexcavationofthechannelprofile.A 2footdropintheelevationoftheprofilecorrespondstothemainstemstagereductionfromnaturalconditionstoCaseEVIconditions.Largecobblesandboulderswillberemovedandusedtostabilizethebanksandchannelizetheflow.Awatersupplysystemwillpipe1cfsfromthemainstemintoPRIlLinordertoincreasethelocalflowavailableforpassageandspawninghabitat.ThecostsassociatedwitheachofthemitigationmeasuresforSlough21areshownbelowandinFigure36:Afterthelargecobblesandbouldersintheupperportionofthesloughareremoved,sortedgravelwillbeprovidedtoincreasetheavailablespawninghabitat.[[[[[[[[[[Miti2ationMeasureExcavationofsloughWatersupplysystemTotal72NumberProE,osedCapitalCosts$34,0001341000$168,000AnnualOperating&Maint.Costs$7,000121000$19,000 I'L"_-",~[[IL~I~rL'"I'---''-"~~~~uI·LJc_Il..,;....;JI~L;ir-L(vii)LowerSideChannel21ImpactIssue•BackwaterEvaluationofbackwatereffectsonavailabilityofspawninghabitatarenotapplicableinlightofthelowbreachingdischarges.•BreachingAseriesofchannelsenterLower'SideChannel21(LSC21)alongitslengthandeachbreachesatadifferentmainstemdischarge.Theuppermostchannel,A6,hasabreachingdischargeof24,000cfswithanassociatedfrequencyofoccurrenceof12percent.SpawningareasbetweentheentrypointofthischannelintoLSC21andnextdownstreamchannel,A5,arelimitedprimarilybythedepthprovidedbylocalflowandnotbreaching.Theexceedanceprobabilityof71percentassociatedwithbreachingdischargesof12,000cfsattheA5channelindicatesthatmainstemoverflowintothesidechannelprovidedtherequireddepthsformuchofthespawnedar~adownstreamfromthispointduringthe1982-1984seasons.ThiswasconfirmedbyfieldobservationsofthechannelatunbreachedconditionsinSeptember,1984inwhichareasspawnedinpreviouslyintheseasonweredewatered.CaseEVIwouldnotprovideproposedbreachingconditionswhilethe12,000cfsCaseEVmaycausethelowerentrychanneltobreach.73 -"--0~-,,-~----".,~,--0-,,~-"-'...."...Jy_J,J-,J,J..J..JJ.J•GroundwaterUpwellingReductionsingroundwaterupwellingforCaseEVIandCaseEVwouldbe77and38percent.•WinterFlowsSimilartoSlough21,theicefrontisonlyprojectedtoreachLowerSideChannel21inthecoldestyears.Theprobabilityofovertoppingislow,althoughthesidechannelwouldovertopbeforetheslough.•RestrictedAccessUndernaturalconditionsthefrequenciesofsuitablepassageconditionsrangefrom71-100percentforPR'sI-X(Table23).UnderCaseEVIconditions,successfulpassageconditionswillbeavailableabout30percentofthetimeatPR'sI-IVandonepercentorlessatPR'sV-IX,basedoncurrentanalysis.ThemajorityofthespawningoccursabovePRVandtheseareaswouldhaverestrictedaccess(Table13).Case-EVshouldprovidepassagethroughallreaches100percentofthetime.-MitigationAtprojectflows,thelackofbreachingflowswillimpactfishpassagewithinSideChannel21.Thefrequencyoffishpassagewillbeincreasedbychannelizingthelocalflow•PassagereachesI-Vwillbeimprovedbyexcavatingachannelthroughthemostrestrictivesectionsofeachpassagereach.74. ,..~Passagereacheschannelizedwithpassagereaches.upstreamofPRVwillberockwingdeflectorsattheLargecobblesandboulderswill....,I....,..J'"'-"-.-Jr~Jcnuccr~.-.,IU[[[[I'Iuberemovedtoimprovethefrequencyoffishpassagethroughthereaches.Marginalspawningsubstrateintheupstreamsloughpoolswillbereplacedwithsortedgravelstoincreasetheavailablespawninghabitat•Winterovertoppingofthebermsalongthelengthof~ideChannel21isnotanticipatedsincetheicefrontontheSustinaRiverisestimatedtobedownstream.(Harza-Ebasco1984a).Thecostsassociatedwitheachofthemitigation.measuresforSideChannel21areshownbelowandinFigure36:AnnualNumberCapitalOperating&MitigationMeasureProposedCostsMaint.CostsExcavationofchannel1$45,000$9,000Wingdeflectorsforbankstabilization7240,00035,000Total$285,000$44,000(d)DevelopmentofNewSpawningAreasCaseEVIandEVflowsduringthespawningseasonwillreducethemainstemflowsfromamedianlevelof15,000cfsfortheAugust20-September20periodtominimumrequiredflowsof9,000and12,000cfs.Thisreductionwillresultinthetransformationofmanysidechanneltosloughs.Areasinwhichspawningwaslimitedbyhighvelocityundernaturalconditionsmaybecomesuitableforspawningassumingotherphysicalhabitatrequirementsaresatisfied.Habitatmodificationstothesenewareasmayprovemorecost-effectivethanthemeasuresrequiredtomaintainthe75 productioninsomeoftheexistings~oughsandsidechannels.Substratemaybeunsatisfactoryeitherbecausetheparticlesizedistributionisoutsidethepreferredrange£or;spawningorthesubstrateisofappropriatesizebuthasbecomeembeddedwithsandsandsiltsunderthenaturalflowregimes.Modificationmeasuresthatwouldbetakentoremedytheseconditionswouldbereplacementofinappropriatesubstratewithsuitablespawninggravelandscarifyingtheembeddedsubstrateparticlestoremovethesandandsilts.Preliminaryscreeningofcandidatemainstemandsidechannelsitesiscurrentl~underway.Siteselectionandmonitoringofphysicalvariablesare.criticalstepsinassessingthepotentialsuccessofproposedreplacementspawningareas.AlistofmainstemandsidechannelsitesatwhichphysicalvariablesarepresentlybeingmonitoredispresentedinTable24.Evaluationsofthepotentialofthesesitestoprovideadditionalspawninghabitatwillbemadeasdatabecomeavailable.3.2.3-ArtificialPropagationAnalternativemeanstoachievethemitigationgoalofmaintainingchumsalmonproductionisthroughartificialpropagation.Mitigationbyartificialpropagationwillbeconsideredifothermitigationmeasuresareineffective.TheartificialpropagationmethodselectedformitigationforchumsalmonspawninghabitatlossesinthemiddleSusitnaRiverisstream-sideeggincubationboxes.'I'heemergentfrywillbereturnedtothesloughsforrearingand/ormigration.Eggboxes76 -...,-,-~withgravityfedwatersystemsarewellsuitedforremote-siteinstallationbecausetheyarecosteffectiveandrequirelittlemaintenance........,---,,~-~-iJ,--'~1-,(a)DesignandOperationofEggBoxAstream-sideeggincubationboxsimilartothatusedextensivelyontheGulkanaRiverinAlaskaforartificialpropagationofsockeyesalmonwouldbeused.Theeggboxisa 4ftx 4ftx8ftgravel-filledupwellingboxcapableofincubating500,000eggs.Theboxwouldbeinsulatedtoprotectagainstfreezing.Ineacheggbox500,000greeneggs(thosejust-fertilized)areplacedonthegravelsurfaceandincubated.Athatching.thealevinsfallormigrateintogravelinterstitialspacesandresidethereuntiltheyolk-sachasbeenabsorbed,atwhichtimetheyemergefromthegravelandleavethebox.Survivalfromgreeneggtoemergentfryhasaveraged85percent(RobesonADF&G,pers.comm.,1984).-,_..J..J-J".....J-'(b)SiteSelectionCriteriaTheprimaryconcerninsitingtheeggboxesistheavailabilityofadependablewatersource.Thewatershouldbesedimentfree,meetwaterqualitystandardsandbegravity-fedtotheeggboxes.Thelatterisofprimaryconcernduetothelowreliabilityandhighcostofpumpingwater.Othercriteriaareaccesstothesiteandproximitytoasloughforjuvenilereleaseandadultreturn.CurryStation(RM120)appearstosatisfytheabovecriteriaforsitelocation.~--~~~----(i)WaterSupplyCurryStationhasanexistinggravity-fedsurfacewatersystem.Usinganexistingsystemismore77 ~,.,--"-,,.,.....,.,,~.....J,-'-,.J,::::;i~-.J.~-Ji,~_J-,.J-'~-'-,:::d.Jeconomicalthandevelopinganewwatersystem.ThesystematCurrywasbuiltinthe1930'sasawatersupplyfortherailwayconstructioncamp.Itconsistsofanimpoundmentstructureandpipelinewhichdrawswateratanestimated5cfsyearround(B.Barrett,ADF&G,pers.corom.,1984).Temperatureandwaterqualityappeartobewithinacceptablelimits(D.Seagren,ADF&G,pers.corom.,1984);however,beforeaneggboxprogramisimplemented,detailedtemperatureandwaterqualitydatawillbeobtained.Informationonthetemporaltemperaturevariationofthewatersourcewillbeusedtopredicttheemergencetimingoffryandtoselecttheproperbroodstock•(ii)SloughProximityAnotheraspectofsitelocationistheproximitytoaslough.Thesloughwillbeutilizedintwoways.First,emergentfryfromtheeggboxeswillbereleaseddirectlyintothesloughforadditionalrearingand/ormigration.Second,thesloughwillserveasanadultreturnareaandwillfacilitateprocurementofthebroodstock.CurrySloughisapproximately4,000feetdownstreamfromCurryStationandcanbeutilized,althoughitmayneedsomemodificationstomakeitsuitable.(iii)SiteAccessCurryStationiseasilyaccessiblebyhelicopterandrail.Thecloseproximityoftherailwaywillfacilitatemovementofmaterialsandequipmenttothesite.78 [[;[[[['[['1".I[[[[.-.,--)l~i[r-'l~~[roo'L(b)BroodStockTheinitialselectionofbroodstockwilldependonthetemperatureprofileofthewatersource.Itappearsthattheexistingwatersourceiscolderthanintergraveltemperaturestowhichincubatingeggsareexposed.Thismaycausethefryproducedfromeggboxtoemergelaterthannativefry.Ifthisdelayexceedsthenaturalvariationinemergencetimingfornativefry,thetributaryspawningchuminthemiddleSusitnaRiver,oranotherstockofearlier-spawningchum,willbeselectedtoallowtheeggboxfishtoemergeatapproximatelythesametimeasnativefry.ThedonorstockwillbeutilizedforthefirstfiveyearsoftheprojectsinceSusitnachumpredominantlyreturnat4an~5yearsofage.Aftertheinitial5yearintroductionperiodthereturningadultswillserveasthebroodstock.Tomitigateforthelossof4,200chum,approximately700,000eggs(250females)willbeneededformitigation.Thisfigureisbasedonmaintainingthe4,200chumescapementusingthefollowingassumptions:1.1:1maletofemaleratio(ADF&G1984a),a15percentegg-to-frysurvival(ADF&G1984b),afecundityof2,850eggsperfemale,anda0.7.percentfrytoadultreturn(includingharvest)(Barricketal.1983).Excessreturnstotheeggboxfacilitywillbeallowedtospawnnaturallyinadjacentsloughs.Toinsuregeneticdiversityoftheartificiallypropagatedstock,eggsfromeachfemalewillbefertilizedwiththegametesofseveralmales.(c)AlternativesforDevelopmentTherearetwoalternativesfortheCurryStationeggboxsite.Thefirstisaplantoestablishtheeggboxsiteat79J ,.,r"'>CurrySloughandthesecondisaplanfordevelopmentoftheeggboxsiteatCurryStation.n--'""·t..,.-,J.-"~.-"'i-.>..J.J(i)CurrySloughDevelopmentEstablishingtheeggboxsiteatCurrySloughwillrequirethewatersourcepresentlyatCurryStation(approximately4,000feetupstream)tobepipedtoCurrySlough.Thiswillentailburying(tosafeguardagainstfreezingandphysicaldamage)approximately4,000feetof6-inchdiameterpipe•TheeggboxeswillbesetupnearthedownstreamendofCurrySloughandemergentfrywillbereleaseddirectlyintothesloughfromtheeggboxes.Thesloughwillbeappropriatelyslopedtofacilitatedownstreammitigationoffryandtoensurethatreturningadultshaveaccesstotheslough.Theadvantageoflocatingtheboxesadjacenttotheslough,isthattheemergentfrycanbereleasedwithoutbeinghandled.Frywillbereleasedintothesloughtoallowforacclimationand/orrearingbeforeseawardmigration.Releasingnewlyemergedfrydirectlyintothemainstemwouldnotallowforacclimationandorientation.ThecostsforthisoptionareoutlinedinAppendixBandsummarizedbelow:J~MitigationMeasureArtificial~ationTotalNumberPr0E,0sed2CapitalCosts$450z.000$450,000AnnualOperating&Maint.Costs$501000$50,000J.oJ--'(ii)CurryStationDevelopmentTheCurryStationdevelopmentconsistsofinstallingtheeggboxesneartheoutfalloftheexistingwater80 --.·~il...,.'-"'""'-.-~--~.-,1"~--.,-'""'""".J.~~)....,..,,;;:,;•.<1-'";;J\,-"...""\...system.Thiswillrequireaminimalamountofpipe,whichcanbeinstalledabovegroundifinsulatedpipeisused.Newlyemergentfrywillbecollectedintwo18-foot-diameterx 4footdeepabove-groundrearingponds.FrywillbetransporteddailytoCurrySloughandliberated.Thisinstallationhasthedisadvantageofextensivehandlingoffry.ThecostsforthisoptionareoutlinedinAppendixBandsummarizedbelow:AnnualNumberCapitalOperating&MitigationMeasureProposedCostsMaint.CostsArtificialpropa~ation2 .$81,000$35,000Total$81,000$35,0003.3-MonitoringStudiesMonitoringstudiesarerecognizedasanessentialprojectsmitigationfeaturethatprovidesforareductionofimpactsovertime(AcresAmerican1982).Operationalmonitoringwillbeconductedto(1)monitorsalmonpopulationandproductionlevelstoensurethatthepredictedlevelofimpactisnotbeingexceeded,and(2)evaluatetheeffectivenessoftheprojectmitigationplan•3.3.1-ImpactMonitoringofSalmonPopulationsSalmonpopulationsintheDevilCanyontoTalkeetnareachwillbemonitoredtoassesswhetherpopulationsmaintainhistoricallevelsduringtheoperationphase.MonitoringwillconsistofenumeratingreturningadultsthatpassSunshineandCurry~-Stationsandmonitoringsmoltout-migrationf~~-·-thereach.Adultswillbeenumerated~g·the--flShwheeltag/recaptureprogramcurrentlybeingusedinthebaselinestudies.The'smoltout-migrationwillbeevaluatedusingasmolttrapprogramsuchaswasconductedduringthe1982to1984baselinestudiesprogram•81 r,IL__[[[[r--L+J[[(~cc[~<.,'r"l___I'l[[r'"--"Theresultsofthesestudieswillbeusedtoevaluatechangesinthepopulationsize,speciescompositionorchangesinstreamusepatternsofthefivePacificsalmonspecies.Resultsofthemitigationmonitoringdescribedinthefollowingsectionwillbe.usedtoassessthecauseofchanges.3.3.2-MitigationMonitoringMitigationfeaturestobemonitoredforevaluationofthelevelofmitigationbeingachievedinclude:-Sloughmodification-Replacementhabitats-EggboxesThemonitoringactivitywillincludeevaluatingtheoperationandmaintenanceprocedurestoensurethatthefacilitiesareoperatingeffectively•If.amitigationfeatureisnotmeetingtheintendedlevelofeffectiveness,modificationstothemitigationfeaturewillbemadetoincreaseitseffectiveness.(a)MonitoringSloughModificationsThevariousfeaturesincorporatedforsloughhabitatmaintenancewillbemonitoredtoassesswhethertheyaremeetingtheirintendedfunctionandareoperatingproperly.Methodsusedtoevaluatethesloughmitigationfeatureswillbeconsistentwithmethodscurrentlybeingusedtoassessbaselineconditionsoftheparameterstobemonitored.Mitigationfeaturesdesignedtoallowadultsalmonpassageintoandwithinthesloughswillbeannuallyinspectedafterbreakuptoidentifyandconductneededrepairspriortotheadultreturn.Annualmonitoringofreturningadultswillallowidentificationofadditionalpassageproblems.Appropriatecorrectiveactionswillbetaken.82 r-,r--I____-Jr-'"!L..;[rLI~L;idModificationstosloughsdesignedtomaintainspawningareaswillbeannuallyinspectedpriortothespawningseasontoverifythattheareacontainssuitablespawningconditionssuchasupwelling,amountofflow,depthofwater,andsuitablesubstrate.Areasthatbecomeoverlysiltedwillbecleaned.Ifsloughflowsdiminishsothatspawningisnolongerpossible,appropriatecorrectiveactionswillbetaken.Thenumberofspawningadultsreturningtothesloughswillbemonitoredannuallytomeasurechangesindistributiontoassessifthecombinationofminimumflowandsloughmodificationsismaintainingnaturalproduction.Thismonitoringwillalsoservetoassesswhetherthecapacityofthemodifiedareasisbeingexceeded.Appropriateremedial.actionswillbetakenwhenspawningsitesareinadequate.n·Iu"~jFryproductionwillbemonitoredannuallyincubationsuccess.Frymonitoringwillassessmentofout-migrationtimingandsuccess.toevaulateincludean[~.-4'.L.<[[r'ur~l...;JIr-'!wTheannualsloughmonitoringwillincludeanevaluationofgeneralsloughconditionsincludingvegetativeencroachment,beaveroccupation,andgeneralconditionofthespawningandrearingareas.Appropriateremedialactionswillbeperformedtomaintainsloughproductivity.Representativesloughswillbemonitoredfortemperatureandsloughflow.Monitoringofthephysicalprocesseswillbecontinueduntilsloughconditionsstabilizeundertheregulatedflowregime.Thismonitoringwillbeusedinparttoassesswhetherfurthermodificationstothephysicalhabitatmustbemadetomaintainsloughproductivity.83 ./.,~~"-,~---./ot,~-'...,-A~J1j....')-A-""-A.."!~.,:1tf)-..,-#(b)MonitoringReplacementHabitatsReplacementhabitatswhichdevelopasaresultofthelowerandmorestableprojectmainstemflowsduringthespawningseasonwillbemonitoredtoquantifyuseoftheseareasbyadultsalmon.Monitoringmethodologywillbesimilartothatcurrentlyusedtoevaluatespawninghabitatsandwillincludestandardphysicalandchemicalmeasurementsaswellasbiologicalanalyses.(c)MonitoringofArtificialPropagationStream-sideeggboxes,ifutilized,willbemonitoredtoevaluatetheireffectivenessinproducingthenumberofreturningchumsalmonforwhichtheyweredesigned•84 ~c-'-<,-"-~i-,-,~..~,._iJ--J-~--'~"i~~:.--~""--,.....J4 -INTERIMIMPOUNDMENTMITIGATIONPLANTheprimarylong-termimpactassociatedwiththefillingoftheWatanaandDevilCanyonreservoirsisthelossofclear-watertributaryhabitat(AcresAmerican1983).ThetributaryhabitatthatwillbeinundatedcurrentlysupportsasubstantialpopulationofArcticgrayling,estimatedtobeatleast16,300fishin1982.Aquatichabitatswithinthereservoirsarenotexpectedtosupportasigni-ficantgraylingpopulation.Intheimpoundmentarea,Arcticgraylingwasselectedastheevaluationspeciesformitigationbecauseofitsabundanceinthearea,itssensitivitytoimpactsduringallseasonsandlifestages,anditsdesirabilityasasportfish.Measurestoavoid,minimize,rectifyorreducetheanticipatedlossofspawningandArcticgraylinghabitatsareconsideredinfeasibl~(AcresAmerican1983).Therefore,measurestocompensateforthelossofArcticgraylinghabitataretheoptionsbeingconsideredforimpoundmentmitigationplanning.ImpoundmentmitigationoptionstocompensateforlostArcticgraylinghabitatwereoutlinedinExhibitE,FederalEnergyRegulatoryCommissionLicenseApplication(AcresAmerican1983)andincluded:(1)fundingofresearchonArcticgraylingpropagationtechnology;(2)hatcherypropagationofArcticgraylingandthesubsequentstockingoftherearedfish(Le.fingerling);(3)stockingofhatchery-rearedrainbowtroutifArcticgraylingpropagationprovedtobetechnicallyinfeasible;and(4)theintroductionofrainbowtrout___---intotheDevilCanyonreservoir.Agencycommentsonthehatchery-rearingofArcticgraylingweregenerallynegativeandconcludedthatgraylingproductioninAlaskamustbeconsideredexperimentalandcompensationmustbejudgedasspeculative(ADF&G1983c).Reasonsforthispositionwere:(1)thelackofareliableeggsource;(2)lowsurvivalfromthegreeneggtofrystage;(3)unsuccessfulattemptstoreargraylingfrytofingerlinginhatcheries;and(4)theinabilitytoevaluatesurvivalofstockedfrybecauseoftheirsmallsize.85 [1,l~n[[[[[coc[ofJccLc[[4.1-MitigationOptions4.1.1RainbowTroutRainbowtroutisthespeciesbeingconsideredforprimarycompensationforlostArcticgraylinghabitat.ArainbowtroutpropagationandastockingprogramhasdocumentedsuccessinAlaskaandthereisahighdemandforthespeciesbysportanglers...ItappearsthatDevilCanyonreservoirmaybetoo.turbidtosuccessfullygrowrainbowtrouttoadesiredsize.TurbiditylevelsinDevilCanyonreservoirareexpectedtobeintherangeof40-50NTUswithlightpenetratingaboutonemeterintothewatercolumn(TomStewart,Harza-Ebasco,pers.comm.1984).PrimaryproductioninDevilCanyonreservoirisexpectedtobelowasaresultoftheturbiditylevels.BecausethesuccessofastockingprogramofrainbowtroutinDevilCanyonreservoirisuncertain,itmaybedesirabletomonitorthereservoirlimnologyandresidentfishpopulationsthatwilloccurnaturallybeforeinitiatingastockingprogramforanyspecies.Sportfishingopportunitieswouldbegreatertoalargernumberofpeopleiffishwerestockednearpopulationcenters.Additionally,stockingsitescanbechosenthatwillhaveahigherprobabilityofsuccessthanDevilCanyonreservoir.RainbowtrouthavebeensuccessfullystockedinnumerouslakesintheMatanuska-SusitnaValleyarea(LarryEngel,ADF&G,Palmer,pers.comm.1984).Casehistories,costanalysesandstockingareasforarainbowtroutstockingprogramwillbediscussedintheimpoundmentmitigationplanscheduledfor1985.4.1.2-ArcticGraylingArcticgraylingstockingisdesirablebecauseof"in-kind"replacementforlostspawningandrearinghabitat.In1984,86 [""1-.)..,r~~...)~j~niJ...J....,J"1J-,o!uI'~J-".....JsignificantprogresswasmadeinArcticgraylingpropagationtechnology.About100,000graylingfingerling(approximately50to60mm)'wererearedatClearHatchery(D.Parks,ADF&GHatcheryManager,Clear,Alaska,pers.comm.1984)•Feedingexperimentswithvariouskindsofcommercialfeeds,automaticfeeders,andincreasedlightintensityarefactorsthatwerethoughttobeimportantinthesuccessfulrearingofgraylingfingerling.Thesurvivalratewasabout70percentfromemergentsac-fryto2gramfingerlingforoneexperimentalgroup,whichisaboutseventimesg.terthanprevioussurvivalratesforemergentsac-frytofingerling.BecausesignificantprogressinArcticgraylingpropagationtechnologyisbeingmadeandthedesirabilityof"in-kind"replacement,graylingisstillconsideredaprimarycandidatespeciesfor.compensation.TheimpoundmentmitigationplanscheduledforApril1985willdiscusspropagationtechnologyforArcticgraylingandexamineareasthatneedfurtherresearch,suchasbroodstockdevelopment,commercialfeeds,vitamindeficiencies,diseaseproblems,stockingevaluation,stockingareas•87 4 -REFERENCESIAcresAmericanIncorporated.1982.SusitnaHydroelectricProject:FishandWildlifeMitigationPolicy.AlaskaPowerAuthority.Anchorage,AK.~:i!AcresAmericanIncorporated.1983.Applicationforlicenseformajorproject,SusitnaHydroelectricProject,beforetheFederalEnergyRegulatoryCommission.Vol.6A.ExhibitE,Chaps.3.AlaskaPowerAuthority.SusitnaHydroelectricProject.,illAirPhotoTech,Incorporated.1983.AerialPhotographsonOctober8,1983.ADF&G1983a.SusitnaHydroAquaticStudies-PhaseIIBasicDataReport,Volume4:AquaticHabit.atandInstreamFlowStudies.1982.AlaskaDepartmentofFishandGame.1981.SusitnaHydroAquaticStudies-PhaseIFinalSpecies/SubjectReport:Adultanadromousfishstudy.PreparedforAcresAmerican,Inc.Buffalo,NY.ADF&G1982b.SusitnaHydroAquaticStudies-PhaseIFinalDraftReport:AquaticStudiesProgram.PreparedforAcresAmerican,Incorporated,Buffalo,NY.~~:!i.j~IReport:AmericanADF&G.1982a.SusitnaHydroAquaticStudies-PhaseAquaticStudiesProgram.PreparedforAcresIncorporated,Buffalo,NY.\ADF&G1983b.SusitnaHydroAquaticStudies-PhaseIIDataReport.\.Wintera~~_~.~~~._~~~,~_~~e~_,~~:~~b~:.._~~~_~.~:~3):_~:~.:ra~~AK.ADF~""9'8'4~;SusitnaHydroAquaticStudies,ReportNo.1:l\"dU'l:~AnadromousFishInvestigations,May-October1983.PreparedforAlaskaPowerAuthority,Anchorage,AK..___-_____.....F&G1984b.SusitnaHydro~natDCStudies,ReportNo.2:Resident~iIeanadromousfishinvestigations,May-October1983.DanaC.Schmidt,StephanS.Hale,DrewL.Crawford,PaulM.Suchanek(eds.).PreparedforAPA,Anchorage,AK.ADF&G.1984c.SusitnaHydroAquaticStudies,ReportNo.3:AquaticHabitatandInstreamFlowInvestigations,May...October1983(ReviewDraft).Chapter6:.AnevaluationofpassageconditionsforadultsalmoninsloughsandsidechannelsoftheMiddleSusitnaRiver.PreparedforAlaskaPowerAuthority,Anchorage,AK.178pp.ADF&G1984d.·SusitnaHydroAquatic~tudies,ReportNo.,3:AquaticHabitatandInstreamFlowInvestigations,May-October1983....../" (ReviewDraft).Chapter1:Stageanddischargeinvestigations.PreparedforAlaskaPowerAuthority,Anchorage,AK.136pp.AlaskaPowerAuthority.1984.CommentsontheFERCDraftEnvironmentalImpactStatementofMay1984.Volume9,AppendixVII-SloughGeohydrologyStudies.Anchorage,AK.·Allen,R.L.1968.PriestRapidsFallChinookSalmonSpawningChannel.BiologicalInvestigations,1966-1967season.Wash.Dept.Fish.Bachen,B.A.Developmentofsalmonidspawningandrearinghabitatwithgroundwater-fedchannels.PresentatPacificNorthwestStreamHabitatManagementWorkshop,October10-11,1984.Humbolt,CA.Barrett,B.1984.PersonalCommunication.AlaskaDept.ofFishandGame.Barrick,L.,B.KepshireandG.Cunningham.1983.UpperSusitnaRiverSalmonEnhancementStudy(Draft)•DivisionofFisheriesRehabilitation,EnhancementandDevelopment,AlaskaDept.ofFish&Game.Anchorage,AK.15pp.Bell,M.C.1973.FisheriesHandbookofEngineeringRequirementsandBiologicalCriteria(Revised1980).PreparedforFisheries-EngineeringResearchProgram,CorpsofEngineers,NorthPacificDivision.Portland,Oregon.Browning,R.1984.PersonalCommunication.U.S.FishandWildlifeService.Harza-EbascoJointVenture.1984a.SusitnaHydroelectricProject:InstreamIceSimulationStudy.PreparedforAlaskaPowerAuthority.Anchorage,AK.Harza-EbascoJointVenture.1984b.EvaluationofAlternativeFlowRequirements.Anchorage,AK.Houston,W.R.andD.Mackinnon.1957.Useofanartificialspawningchannelbysalmon.Trans.AmericanFish.Soc.86:220-230.King,D.1984.PersonalCommunication.Olympia,WA.Wash.Dept.Fisheries,Lister,D.B.,D.E.MarshallandD.G.Hickey.1980a.ChumSalmonsurvivalandproductionatsevenimprovedgroundwater-fedspawningareas.Can.M.S.Rep.FishAquat.Sci.1595:X+58pp.Lister,D.B.&Associates,Ltd.1980b.StreamEnhancementGuide.ProvinceofBritishColumbia,MinistryofEnvironment,Vancouver,BC,Canada. Meekin,T.K.1967.McNarySupplementalSpawningChannel.Sum.Rep.(1957through1966).Wash.Dept.Fish,ArmyEng.Cont.N.D.A.35-026-Civeng-S8-23andNo.D.A.45-164Civeng-6S-4.Meekin,T.K.,R.L.AllenandA.C.Moser1971.AnEvaluationoftheRockyReachChinookSalmonSpawningChannel,1961-1968.InWash.Dept.FishTechRep.6.R&MConsultants,Inc.1982.Task3 -Hydrology,SloughHydrologyPreliminaryReport.PreparedforAcresAmerican,Inc.NewYork.R&MConsultants,Inc.1983.SusitnaHydroelectricProject:SusitnaRiverIceStudy(Task4).PreparedforHarza/EbascoJointVenture.Anchorage,AK.183pp+maps.R&MConsultants,Inc.1984.MemorandumReport:LocalRunoffintoSloughs.PreparedforHarza-EbascoJointVenture.Anchorage,AK.Robeson,K.1984.PersonalCommunicationADF&G.Glennallen,Alaska.Schmidt,D.1984.PersonalCommunication.AlaskaDepartmentofFish&GameSuHydro.Anchorage,Alaska.Seagren,D.1984.PersonalCommunication.ADF&GSuHydro.Anchorage,Alaskau.S.Fish&WildlifeService.1982.EndangeredandThreatenedWildlifeandPlants.FederalRegisterSOCFR17.11and17.12.January1,1982.......-7." r~r-Jc-Jc-Jc-;-)r-J.-,C-.]C["-JL~lJ[-Jl-lc----;c-JC-:-JC~I,-JI..",J,"Table1.SusitnaRiverannualsalmonescapementbysub-basinandspecies.Sub-basinSockeye1Chum22Pink34CohoChinookTotalLowerSusitnaRiver(RM11,90017,00039,900Even427,40056,300Even552,500oto80)excl~dingYentnaOdd44,800Odd169,900River(RM28)YentnaRiver(RM28)6119,20019,50020,000Even447,30044,700Even650,700Odd48,400Odd251,800Talkeetna(RM97.1)and116,000295,60024,700Even388,40016,100(62,000)Even840,800Chulitna(RM98.6)riversOdd40,600Odd493,000includingSusitna'iverfromRM80to98.6TalkeetnaStationto82,80024,1002,20QEven54,8008,500(9,500)Even92,400DevilCanyon(RM98.6to152)Odd4,400Odd42,000986800Even1,317,900Even2,136,400TotalSusitnabasin249,900356,200125,600,Odd138,200Odd956,700]1234567891981-83averageofADF&Gsecond-runsockeyeescapements1981-83averageofADF&GescapementestimatesEvenyear1982only;oddyear1981and1983average;fromADF&GescapementestimatesMinimumestimatesofescapementfromADF&G1983surveycountsandconversionfactorof52%(NielsonandGeen1981);numbersinparenthesisare1982-83averageofADF&GescapementestimatesLowerSusitnasub-basinequalstotalSusitnabasinescapementminusYentnaandSunshineescapementsYentnasub-basinescapementfromADF&GestimatesatYentnaStation(TRM04)Talkeetna-Chulitnasub-basinescapementequalsSunshineStation(RM80)escapementminusTalkeetna-DevilCanyonsub-basinescapementTalkeetnaStation-DevilCanyonsub-basinescapementequalsTalkeetnaStation(RM103)escapementminusmillingfishthatreturndownstream.Millingrates:sockeye30%,chum40%,pink25%,chinook25%,coho40%(Barrett1984)TotalSusitnabasinescapementequalsYentnaStation(TRM04)escapementplusSunshineStation(RM80)escapementplus:5%forsockeye,48%forpink,5%forchum,85%forcoho(Barrett1984) -IjJ--)!LTable2.ChumsalmonpeakindexcountsbyhabitattypeaboveRM98.6,1981-1983.Includesmainchannelandsidechannelhabitats[[[r-,-).,--'--,.-J.,3-YearHabitatType1981 19821983Total_.-Maiilstem116550219785Streams2411,7371,5003,47822,5962,2441,4676,307SloughsTotal2,8534,5313,18610,570Source:ADF&G1981a,1982a,1984a1J,JJ--1-,...JJd-:,J.,--1...,J-'2Includesuplandsloughandsidesloughhabitats ~.,-'Table3.ChumsalmonpeakindexcountsinsloughsaboveRM98.6,1981-83• IL..JOr-CI1-wI~wr-~L.JO,-'wLSource:ADF&G1981a,1982a,1984a ~,"-'--,-'---,~I~....J-,~-'Source:ADF&G1984a Table6.-,Selectedriverswithhydroelectricprojectsandassociatedmitigationsforanadromousfishspecies.TerrorLake,AKAverageDischarge:Pre-project279cfs,post-project181cfs.Species:Pink,chumandcohosalmon,DollyVarden.Projects:AlaskaPowerAuthorityproject.diversiondamforhydroelectricMitigation:TyeeCreek,AKSpecies:Projects:Mitigation:BlueLake,AKSpecies:Projects:Mitigation:KetchikanCreek,AKSpecies:Projects:Mitigation:SolomonCreek,AKSpecies:Projects:Mitigation:Instreamflowrequirementsandmonitoringprogram.Intertidalspawningpinkandchumsalmon.AlaskaPowerAuthority-diversiondamforhydroelectricprojectsmayeliminateflowtoTyeeCreek.Spawninggravelswereaddedtothetailraceareaasreplacementspawninghabitat.Pink,chumandcohosalmon,DollyVarden.CityofSitka,diversiondamInstreamflowrequirements.Naturalandhatcheryrunsofchinook,pink,cohoandchumsalmon.KetchikanPublicUtility,damandpowerhouseInstreamflowrequirementsChum,pink,andcohosalmon.AlaskaLightandPower,damandpowerhouse.Instreamflowrequirementsandflowfluctuationrestrictionstopreventdepositionoffinesduringhighflowperiod. -,-)"""'ITable6(Continued).,_J~-'SkagitRiver,WAAverageDischarge:15,190cfs(belowBakerRiver).BelowCityofSeattleprojectaveragedischarge4282cfstoBakerRiver.,.J,,J,-',.JSpecies:Projects:Mitigation:BakerRiver,WASummerchinook,fallchinook,.sockeye,pink,cohoandchumsalmon,steelhead;spring,summerandfallchinook(mainriverandtributaryspawning).Pinksandchums(mainriverspawningandtributaryspawning).Steelhead(mainsternandtributaryspawning).ThreeCityofSeattleprojects(llarge,1medium,1smallstoragereservoirs,allwithpowerplants).Minimumflowsforpreventionofjuvenilestranding.Rampingraterestrictions.AugmentationfromahatcheryatMarblemount.Thesefeatureswerenotinoperationwhen.theCityofSeattlebeganoperationsandresultedfromavoluntaryagreementbetweentheCityofSeattleandstateagencies.-,AverageDischarge:2,520cfs-".,Species:Riverhadspringchinook,sockeye,cohoandsteelhead.hasonlysockeyeandcoho.Now..J,..J.,-'Projects:Mitigation:SultanRiver,WAPugetSoundPower&LightCompany(2dams&2powerhouses)Fisharetrappedbelowlowerdamandhauledabovetheupperdam.Trapsareusedinthelakesforcollectionanddownstreampassage•,..-.4AverageDischarge:775cfsSpecies:cohoandsteelheadpresent•-,..;JProjects:CityofEverett-watersupply.damand1powerhouse)•SnohomishCountyP.U.D.(1~.J-~--'Mitigation:Noneformanyyears.Nowhasaflowcontrolprogram. -,.,Table6(Continued)ToltRiver,WA--,.,AverageDischarge:575cfs,-y--"Species:Projects:Mitigation:Pink,coho,fallchinookandchumsalmon,fallchinookandsteelheadtroutDiversiondam.CityofSeattle-watersupply.Hasminimumflowcontrolregulation-Y.,J-.."----"-'"..J,J.,..JCedarRiver,WAAverageDischarge:684cfsSpecies:Sockeye,steelhead,chinookProjects:CityofSeattle-watersupplyandsmallpowerhouseMitigation:Flowcontrolregulationimplemented,plusanewhatchery.GreenRiver,WAAverageDischarge:1,270cfsSpecies:Summerandfallchinookandsteelhead(Manyyearsagohadpinkandchumruns.)-"-'Projects:Mitigation:CityofTacoma-watersupply(diversionofflow)Hasminimumflowreleaseregulationforfisheries.-"WhiteRiver,WAJ-:-~AverageDischarge:1,372cfsSpecies:Springchinookandsteelhead(smallcohorun)J_J;-.>-'---'Projects:Mitigation:CorpsofEngineers-floodcontrol.PugetSoundPower&LightCompany-diversionofflowwithlakestorage.Hasminimumflowrelease.Screendiversion.Issueresolutioncontinuing [[[Table6(Continued)NisquallyRiver,WAAverageDischarge:1,695cfsSpecies:Springandfallchinook,pink,cohoandchumsalmon[cProjects:CityofTacoma(2powerhousesand1storagedam).Centralia-diversionofflow.Cityof[cc[[c[cMitigation:Instreamflowrequirementsforsalmon.Citybuiltahatchery(about1916)whichwasnotusedandisnowgone.ElwhaRiver,WAAverageDischarge:1450cfsSpecies:Summerchinook,pink,cohoandsummerandwintersteelheadProjects:RayonierPulpandWashingtonPulpandPaper(2dams,2powerplantsand1storagereservoirbehindupperpowerhouse).Mitigation:Nomitigationinitially(1914)atlowerdam.Leakagehaskeptfishrunsbelowthelowerdamalive.NowhasrearingpondandIndianhatcherytohelpsupportsalmonruns.NationalParksServiceplanstoreopenareaaboveupperdamforanadromousstocks.WynoocheeRiver,WAAverageDischarge:750cfs(abovethedam)Species:Coho,chumandsteelheadProjects:CorpsofEngineersdam(floodcontrolandwatersupply).Apowerplantandahatcheryarenowplanned.[Mitigation:Flowreleasebasedonrivercrosssectionalwork.[CowlitzRiver,WAAverageDischarge:9,330cfs[[[r'L.iSpecies:Projects:Mitigation:Springchinook,fallchinookandcohosalmonandsteelheadtroutCityofTacoma(1largestoragebasinand2powerplants)Flowregulationrequiredinlicense.Nowhastwohatcheries. Table6(Continued)LewisRiver,WAAverageDischarge:4,897cfsSpecies:Springchinook,fallchinookandcohosalmonandsteelheadProjects:Threemajordamsandpowerhouses.Mitigation:Hasflowregulationbelowlowerdam.Initiallyahatcheryforspringchinookwasconstructedandoperated.Fallchinookkeptalivebyflowcontrol.BigWhiteSalmonRiver,WAAverageDischarge:1,075cfsSpecies:Projects:Mitigation:Fallchinook.Verylimitedareaforspawningbelowdam.PugetPowerandLight-ConditDamFisharetakenandeggsshippedtoahatcheryforartificialpropagation.Earlyfishhatcheryfailed,rebuiltandfailedagain.Siteoffirstattempttobrailfishaboveadam.UpperColumbiaRiver,WAAverageDischarge:(GrandCouleeDam)64,800cfsMitigation:SnakeRiver,IDThreehatcheriesbuilttoperpetuaterunswhichwentabovedam.AverageDischarge:20,650cfsSpecies:Springandlatesummerchinookandsteelhead.(Hadatonetimearunofcoho.)~'-Projects:IdahoPowerCompany-HellsCanyonDam(lowestofthreedams)Mitigation:FlowregulationandhatcheryatBrownlee.FisharetrappedatHellsCanyonforartificialpropagation.Thereareminimumflowrequirementsandrampingratelimitations.~! Table6(Continued).NorthSantiamRiver,ORAverageDischarge:3,367cfs.Species:Project:Mitigation:ClackamasRiver,ORSpringchinook.Thereismainstreamspawning.Has1largestoragereservoirandpowerplantand1reregulationpoolandpowerplant(CorpsofEngineers).Adultstrappedforeggcollectionandhatcheryrearing.AverageDischarge:3,636cfs.Species:SpringchinookProjects:PortlandGeneralElectricCompany- 3plantsMitigation:Havefishwaysandpartialscreening.DeschutesRiver,ORAverageDischarge:830cfsSpecies:Projects:Mitigation:Springandfallchinookandspringandsummer(orfall)steelheadPeltonDam-PortlandGeneralElectricCompanyHasadamabovewhichincludesahatchery.Hasafishwaywhichhasproblemsassociatedwithseasonalflowchanges. Table7Areaspawnedwithinslough8Abackwaterzoneand.areasbetweenpassagereachesfor1982,1983and1984•.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.AreaSpawned(ft2)Composite/198219831984CompositeTotalBackwaterZone19,70017,90093,700103,400.79PassageReachesI -II21,90020,20094,700107,100.78II-III4,1002,90029,20031,800.88III-IV5,90012,40070,80072,700.82IV-V0 010,40010,4001.0V-VI0 012,90012,9001.0VI-VII8,60002,00010,300.97VII-VIII7,80006008,4001.0VIII-IX005,2005,2001.0IX-X0 0 000 Table8Areaspawnedwithinslough9backwaterzoneandareasbetweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.AreaSpawned(ft2)Composite/198219831984CompositeTotalBackwaterZone01,20001,2001.0PassageReachesI-II01,20001,2001.0II-III13,50023,90018,10047,200.85III-IV7,5004,0004,00011,200.79IV-V7,7003,2006,90011,700.76V-VI4,6002,9004,0005,300.46 Table9.Areaspawnedwithinslough9Abackwaterzoneandareasbetweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.AreaSpawned(ft2)Composite/198219831984CompositeTotalPassa~eReachesI-II6,50012,8002,3008,800.41II-III14,3004,4001,6008,800.43III-IV10,4004,3005,700.13,800.68IV-V21,60016,40011,10026,300.54V-VI6,900 7,60013,80012,300.44VI-VII21,4007,3004,90027,600.82VII-VIII00000VIII-IX2,2004,8006,2007,700.58IX-X8,8006,10012,80018,400.66X-XI2,20006,6008,8001.0 Table10Areaspawnedwithinslough11backwaterzoneandbetweenpassagereachesfor1982,1983and1984.ratioofthecompositetothetotalareaspawnedallyearsisalsoshown.areasThefor./."AreaS£awned(ft2)198219831984CompositeComposite/TotalBackwaterZone13,10025,80035,00050,200.68PassageReachesI-IIII-IIIIII-IVIV-VV~VIVI-VII13,40025,80040,90056,200.704,10009,7009,700.7015,2007,30038,20046,200.765,00003,5005,200.612,9003,6004,0005,800.5527,0009,90019,10032,600.58 .'.Table11.AreaspawnedbetweenpassagereacheswithinSideChannel21for1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.'AreaSpawned(ft2)Composite!1982 19831984CompositeTotalI22,50032,00011,90032,000.48II1,3002,2003,1004,100.62III0 0 000 Table12.AreaspawnedbetweenpassagereacheswithinSlough21forj1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.AreaSpawned(ft2)Composite/198219831984CompositeTotalPassageReachesI-II3,40012,10010,00019,100.75II-III2,90033,60021,90038,900.67 ___.1Table13.AreaspawnedwithinSideChannel21backwaterzonesandareasbetweenpassagereachesfor1982,1983and1984.Theratioofthecompositetothetotalareaspawnedforallyearsisalsoshown.~AreaSpawned(ft2)Composite/198219831984CompositeTotal'--''"BackwaterZone80,500178,600L80,100239,300.71PassageReaches"IL.I-II003003001.0II-III06,3009,0009,000.59III-IV03,6002,2003,700.64IV-V19,70021,50063,40065,900.63uV-VI1,50013,2007,80019,000.84VI-VII3,30006003,9001.0VII-VIII33,30017,70074,300105,200.84VIII-IX0 0 000IX-X00 000X-XI22,30018,30021,00032,400.53-"'~-~-,"--''-'LJ~-..; ----,,.-<t_",I..~-....,~,L-"'---",IU--,IUl~~i-'i~,,.---J......:'"l~J[[[[LTable14.MeanmonthlydischargesatGoldCreekfornaturalconditions.NaturalCaseP-1Month(cfs)(cfs)January1,44010,900February1,2109,200March1,0907,900April1,3407,300May13,4008,800June28,15010,500July23,9908,900August21,9509,800September13,77010,900,October5,58010,200November2,43020,600December1,75012,100 Table15.RelationshipbetweenmitigationalternativesandtheimpactsforwhichtheyareapplicableWinterLossofLossofovertopping---,Mitigationalter-Inadequatephysicalupwellingofsloughnatives/impactissuepassagehabitatathabitatbermchannelwidthmodificationP-,channelbarrierconstructionP-.,FlowaugmentationPPSUpwellingaugmentationSSp-~SloughexcavationPPS"-creatingspawninghabitatinpoolsPSIncreasebermheightP--,P=primaryeffectS=secondaryeffect-'_...,;IJ Jl.JlIi\..~.~,.JJjJTable16.SummaryofestimatedcostsforhabitatmodificationmeasuresinselectedsloughsandsidechannelsTotal355,00023,500213,00022,500226,00012,500286,00026,500176,00012,500168,00019,000285,00044,0001,709,000125,500 ~~JTable17.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough8A.BWisbackwaterconditionwhichneglectstheeffectoflocalflowBRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughswjGWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.loc~(~AppendixBcontainsanexplanationofthederivationofthepercentexceedancevalues -.,---1Table18Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough9.'-,PassageNaturalProject12,000cfsProject9,000cfsProject8,000cfs"ReachCondoOccurrenceCondoOccurrenceCondoOccurrenceCondoOccurrence(%)(%)(%)(%).~ISW/GW100SW/GW100SW/GW47SW/GW44IISW/GW100SW/GW100SW/GW100SW/GW100,IIISW/GW18SW/GW16SW/GW15SW/GW14...JIVSW/GW17SW/GW16SW/GW14SW/GW14".VBR29---0---0---0~...."-.-JBWisbackwaterconditionwhichneglectstheeffectoflocalflow~_.,,...J;~---1BRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughSW/GWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.AppendixBcontainsanexplanationofthede~ivationofthepercentexceedancevalues [[[[~~-~r-'L_,[[[[[[f't-lr~l_J[[[r'l----,[r~'--'Table19.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough9A.PassageNaturalProject12,000cfsProject9,000cfsProject8,000cfsReachCondoOccurrenceCondoOccurrenceCondoOccurrenceCondoOccurrence(%)(%)(%)(%)ISW/GW100SW/GW100SW/GW100SW/GW100IISW/GW100SW/GW100SW/GW100SW/GW41IIISW/GW100SW/GW100SW/GW32SW/GW14IVSW/GW100SW/GW100SW/GW100SW/GW100VSW/GW100SW/GW100SW/GW100SW/GW20VISW/GW100BR100SW/GW24SW/GW14VIISW/GW100BR100SW/GW10SW/GW7VIIISW/GW100BR100SW/GW6SW/GW3IXSW/GW100SW/GW100SW/GW3SW/GW2X---0---a---a---aBWisbackwaterconditionwhichneglectstheeffectoflocalflowBRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughSW/GWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.AppendixBcontainsanexplanationofthederivationofthepercentexceedancevalues -,'I)[~,.-,j--,--',-,---'-,--',~-J--'_J-'--','---'--'Table20.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough11.PassageNaturalProject12,000cfsProject9,000cfsProject8,000cfsReachCondoOccurrenceCondoOccurrenceCondoOccurrenceCondoOccurrence(%)(%)(%)(%).ISW/GW70SW/GW60---0---0IISW/GW43---20---0---0IIISW/GW12---5---0---0IVBR1---0---0---0VBR1---0---0---0BWisbackwaterconditionwhichneglectstheeffectoflocalflowBRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughSW/GWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.AppendixBcontainsanexplanationofthederivationofthepercentexceedancevalues ,~.,Table21.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatUpperSideChannel11.PassageNaturalProject12,000cfsProject9,000cfsProject8,000cfs,ReachCondoOccurrenceCondoOccurrenceCondoOccurrenceCondoOccurrence-'(%)(%)(%)(%),ISW/GW100---0---0---0IIBR45---0---0---0--.IIIBR45---0---0---0J--.J...;;--'.JBWisbackwaterconditionwhichneglectstheeffectoflocalflowBRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughSW/GWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.AppendixBcontainsanexplanationofthederivationofthepercentexceedancevalues -,~'I__J--,--,-<)-),--'-'--,_J~~~~Table22.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercerttoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSlough21.PassageNaturalProject12,000cfsProject9,000cfsProject8,000cfsReachCondoOccurrenceCondoOccurrenceCondoOccurrenceCondoOccurrence(%)(%)(%)(%)IswjGW100swjGW100swjGW6SwjGW4IlLSwjGW10---0---0---aIlRswjGW4swjGW2SwjGW1SwjGW1BWisbackwaterconditionwhichneglectstheeffectoflocalflowBRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughswjGWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.AppendixBcontainsanexplanationofthederivationofthepercentexceedancevalues ~.)~---,Table23.Conditionwhichprovidessuccessfulpassagemostfrequentlyandapproximatepercentoftimethatpassageissuccessfulduringtheperiod20August-20SeptemberatSideChannel21.~PassageNaturalProject12,000cfsProject9,000cfsProject8,000cfsReachCondoOccurrenceCondoOccurrenceCondoOccurrenceCondoOccurrence(%)(%)(%)(%)ISW/GW100BR100SW/GW28SW/GW24IISW/GW100BR100SW/GW28SW/GW24-,IIISW/GW100BR100SW/GW31SW/GW26-jIVSW/GW100BR100SW/GW31SW/GW26-,71100SW/GW1SW/GW0.5VBRBRVIBR71BR100SW/GW0.5---aVIIBR71BR100SW/GW0.5---a-',VIIIBR71BR100SW/GW0.5---a--'IXBR71BR100SW/GW0.5---aXSW/GW100SW/GW100SW/GW9SW/GW5_,J-----'BWisbackwaterconditionwhichneglectstheeffectoflocalflowBRisbreachingconditionwhichrepresentscontrollingdischargethroughthesloughSW/GWissurfacewaterandgroundwaterconditionwithamediannaturalfloworminimumprojectflowcontrollinggroundwaterlevelsandsurfacewaterrelatedtoprecipitationevents.AppendixBcontainsanexplanationofthederivationofthepercentexceedancevalues IrTable24.Candidatesitesfordevelopmentofreplacementspawninghabitat.Historicalr-~*RM.SiteLocationSpawningUse1...--""'",-,r-,ILj,..,.,....~.110.1LMouthofOxbowIchum115.0RMainstem2,rightchannelchum117.9LChanneloutsideofBushrodchum118.9LDownstreamofOxbowImouthchum127.1LorCComplexDownstreamofmouthSL9chum129.8RRightsideofsidechannelatheadofSL9chum131.3LUpstreamof4thofJulyCreekchum132.9RDownstreamofmouthofSL9Achum137.5LDownstreamofmouthofSL16139.0LBetweenmouthofS~17and18chum,sockeye143.2LUpstreamofintertiechum*LLeftsideofchannellookingupstreamCCenterofchannelRRightsideofchannellookingupstream IL.-'ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTHARZA-EBASCO~CoMuIt8ntae;,1SUSITNAJOINTVENTUREFIGURE11982-1983SUSITNACHINOOKESCAPEMENTANDRELATIVE.UTILIZATIONTALKEETNA-DEVILCANYONSUB-BASINTOTALESCAPEMENTUNKNOWNOLOWERSUSITNASUB-BASIN~TALKEETNA-CHOL1TNA~SUB-BASIN1:1:111:\li:.I!I.I:llillYENTNASUB-BASINCOOKINLETUNKNOWNESCAPEMENTDEVILCANYON(FISHBARRIER)IIMAINSTEM:0%ITRIBUTARIES100%..l~SLOUGH0%........-."r[I~(rIJr-L[[[[[[[[[[ TALKEETNA-DEVILCANYONSUB-BASINTOTALESCAPEMENT356,200~TALKEETNA-CHULITNA%SUB-BASINl:i'il!l!ili!,I'!,i!!I:!i!:1YENTNASUB-BASINDLOWERSUSITNASUB-BASIN17,000,DEVILCANYON(FISHBARRIER)IIMAINSTEM~7%TRIBUTARIES33%""'"•.•SLOUGHS80"L..ii'r~ul-'.'[[[[[I-~CnL_~,[[[[[l-'--"[COOKINLETFIGURE21981-1983SUSITNACHUMESCAPEMENT,ANDRELATIVEUTILIZATION,,-_......ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECT'--"...-._,fClydeConsuttantaElIHARZA-EBASCOSUSITNAJOINTVENTURE'--' --,~,,".OPSLOUGHS99%DEVILCANYON(FISHBARRIER)..MAINSTEM11%I0%L---...I.......I"ITRIBUTARIES~-.2,800TALKEETNA-DEVILCANYONSUB-BASIN~TALKEETNA-CHULITNA~SUB-BASINTOTALESCAPEMENT249,9001\\\\[':\\\.\',[",,:[,[,\\\1YENTNASUB-BASINOLOWERSUSITNASUB-BASIN11,900"-}--!-.,-'---,-"",...J:-1COOKINLET:->FIGURE311981-1983SUSrrNASOCKEYEESCAPEMENTANDRELATIVEUTIUZATION""••ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECT->WDodwwda,deeon."a..61HARZA-EBASCOSUSITNAJOINTVENTURE [,DEVILCANYON(FISHBARRIIER)IMAINSTEM;c1%YENTNASUB-BASINTALKEETNA-DEVILCANYONSUB-BASIN~TALKEETNA-CHULITNA~SUB-BASINDLOWERSUSITNASUB-BASIN.;>SLOUGHS<1%39,9002,200TRmUTAR~S99%,_r--""'1r-L,-',L["_J[[[r~[[[TOTALESCAPEMENT86,800[[[[0COOKINLETFIGURE41981-1983SUSITNACOHOESCAPEMENT,ANDRELATIVEUTILIZATIONALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTHARZA-EBASCOw.-t-~a,deConUt8ntae91SUSITNAJOINTVENTURE'-' l~[DEVILCANYON(FISHBARRIER)MAINSTEMI096TRIBUTARIES9596..It..tSLOUGHS596rl~EVENYEAR(1982)RUNSX10[4,400TOTALESCAPEMENT138,200TALKEETNA-DEVILCANYONSUB-BASIN~TALKEETNA-'CHULITNA~SUB-BASINl.j!I!!'!I!.:j!.:!i:;li:J.YENTNASUB-BASINOLOWERSUSITNASUB-BASIN44,800"..~IL,I'L••[>--01L';COOKINLET"1-'--.[[l~FIGURE5ODD-YEAR(1981&1983)SUSITNAPINKESCAPEMENTANDRELATIVEUTLIZATIONALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTHARZA-EBASCO.adwa~ConMIftantsE91SUSITNAJOINTVENTURE'--' TOTALAREASPAWNEDISTHESUMOFTHEAREASPAWNEDFOREACHOFTHETHREEYEARS.~[r~L_J[[[[[[[[[r~L;~IIIl----COMPOSITEAREASPAW-NEDISTHETOTALSURFACEAREAUSEDFORSPAWNING.AREASPAWNEDIN1982.AREASPA-WNEDIN1983.AREASPAWNEDIN1Sa.t..[[:.,J[[[[1-'L,FIGUREeSCHEMATICDIAGRAMI.LUSTRAT1NGDIFFERENCEBETWEENCOMPOSITEAREAANDTOTALAREASPAWNED.ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTHARZA-EBASCOWoodwBrd-CIrdeConsultanbE91SUSITNAJOINTVENTURE 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[-)[)II~JlJlL.JlJl.1lJJv1..CJ)Il.595TH~ESHOLDELIEV.,-------------.------.-----..._-"",---...,,5901,-,,p/..,-----'\,\,-\JI&.-----'---;--------,\,,-.....,..\,\.....->585VW..J580Wen~575NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL19711972WEATHERPERIOD1NOV71-.30APR72(COLDWINTER)595THR.ESHOLDELV.5901,..I-585I&.....:>I"__..__"'--~~---7----1-·---"'---'------,.--...W580..JWen575~NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL19821983WEATHERPERIOD1NOV82-30APR83(AVERAGEWINTER)LEGEND-NATURALFLOWANDWEATHER----WATANA1996FLOWANDNATURALWEATHER.REF:HARZA-EBASCOSUSITNAJOINTVENTURE.1984.INSTREAMALASKAPOWERAUTHORITYICESIMULATIONSTUDY.DRAFTREPORTPREPAREDFORALASKAPOWERAUTHORITYFORSUSITNAHYDROELECTRICPROJECT.SEPTEMBER.SUSITNAHYDROELECTRICPROJECTFIGURE8PREDICTEDWINTERMAINSTEMSTAGESFORNATURALANDWoodward-aydePROJECTFLOWSNEARTHEHEADOFSLOUGH8AConsultants~.OO&rrJ~~~~~aUalTH4JOINTVfHTU"1 l.l.l..jl.J.Jl.Jl...Jl..JICJJ615610ETHRESHOLDELI:V./'-----J---,___,--------,--.,--,I ',,/'.\-605>.j--------'~,.,I'\,\_-I,W------,---,------,'-,----',,..JW600.(I)'..~595NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL18711872WEATHERPERIOD1NOV71-30APR72(COLDWINTER)620615E610-TrRESHOLDELEV.:;;w605..JVw---'---7--..------.",.-----,--,---,----.,------,---------....._J--------..cd_...._--~---\600~NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL18821883WEATHERPERIOD1NOV82-30APR83(AVERAGEWINTER)LEGEND-NATURALFLOWANDWEATHER----WATANA1988FLOWANDNATURALWEATHERREF:HARZA-EBASCOSUSITNAJOINTVENTURE.1884.INSTREAMALA'SKAPOWERAUTHORITYICESIMULATIONSTUDY.DRAFTREPORTPREPAREDFORALASKAPOWERAUTHORITYFORSUSITNAHYDROELECTRICPROJECT.SEPTEMBER.SUSITNAHYDROELECTRICPROJECTFIGURE9PREDICTEDWINTERMAINSTEMSTAGESFORNATURALANO\YoodwardoCtydeD{)~f?J~c.~®&~PROJECTFLOWSNEARTHEHEADOF.SLOUGH9ConsuJtants"IUIITHAJOINTVENTU"( Cjc-J["")c-JC-;)C--}c-J[~c-Jc.-.Jc-Jc=JC--JC-]r._-,'..,..)665660ofTHRSHOLDELV.~.-.-~---,.--~~_.---..,--,.;.--'".....,>655/I,W_.I,...II,W650--._..'J-'---,------..".-en~64NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL18711872WEATHERPERIOD.1NOV71-30APR72(COLD\\lINTER).665660fTHRSHOLDEL~V.655.....>W650---------...I-/,-------w0645~NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL18821883WEATHERPERIOD1NOV82-30APR83(AVERAGEWINTER)LEGEND-NATURALFLOWANDWEATHER••••WATANA1888FLOWANDNATURALWEATHER-REF:HARZA-EBASCOSUSITNAJOINTVENTURE.1884.INSTREAMIALASKAPOWERAUTHORITYICEBIMULATIONSTUDY.DRAFTREPORTPREPAREDFORALASKAPOWERiAUTHORITYFORSUSITNAHYDROELECTRICPROJECT.SEPTEMBER.,SUSITNAHYDROELECTRICPROJECTFIGURE10PREDICTEDWINTERMAINSTEMSTAGESFORNATURALAND'Noodward-CJyde(}{)~[FJtl&~~~~PROJECTFLOWSNEARTHEHEADOFSLOUGH8AConsultants"IUSITN4JOINTVfNTUA! r-Jc-Jc-J['~,~[~L-JC-Jc=Jr=JlJL~[~C-,Jc-J[-]C--J[.~c--J[--1.J695THRSHOLDELr:V.690E......,-.,,----...-'---.,....J",,,,,.~,.-:;.:685--,._.,---,---------------r--......-......\,------...--W'.-...J,------,--W680u).,~675'NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL19711972WEATHERPERIOD1NOV71-30APR72(COLDWINTER)695THRISHOLDELlv.690E685.....-~_...----------------r----,._-----._-"""--,---.._-."'--------,__J"'---'\---,'>----.,----.---W680..JWu)675~NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL19821983WEATHERPERIOD1NOV82-30APR83(AVERAGEWINTER)LEGEND-NATURALFLOWANDWEATHER----WATANA1998FLOWANDNATURALWEATHERREF:HARZA-EBASCOSUSITNAJOINTVENTURE.1984.INSTREAMALASKAPOWERAUTHORITYICESIMULATIONSTUDY.DRAFTREPORTPREPAREDFORALASKAPOWERAUTHORITYFORSUSITNAHYDROELECTRICPROJECT.SEPTEMBER.SUSITNAHYDROELECTRICPROJECTFIGURE11PREDICTEDWINTERMAINSTEMSTAGESFORNATURALANDWoodwardo~lXJ&rfJtz£c:{~(ID&~PROJECTFLOWSNEAR,THEHEADOFSLOUGH11Consultants"IUIITH"JOINTY[HTU,.( LJl.L.)II..l.jl..Jl.JLJlJlJl.JllJJlJ.J765760ETH~ESHOLDEL~V.-755.,;-----,,--.,--------------------.......---------.-'------'..--..--fo--....."'-,,------,-'--,._---.,-W....750Wui~7"5NOVEMBERDECEMBERJANUARYFEBRUARYMARCHAPRIL19711972WEATHERPERIOD1NOV71-30APR72(COLDWINTER)765760ETHRlSHOLDELV.755-.,;.__--..1---,------------.....------f--~___;-.-------.1-41---411__.,.-------,__J----.--"-..W750.-'--_._.-'"....Wui7"5~NOVEMBERDECEMBERJANUARYFEBRUARYMARCH'.APRIL19821983WEATHERPERIOD1NOV82-30APR83(AVERAGEWINTER)LEGEND-NATURALFLOWANDWEATHER----WATANA1998FLOWANDNATURALWEATHERREF:HARZA-EBASCOSUSITNAJOINTVENTURE.1984.INSTREAMALASKAPOWERAUTHORITYICESIMULATIONSTUIDY.DRAFTREPORTPREPAREDFORALASKAPOWERAUTHORITYFORSUSITNAHYDROELECTRICPROJECT.SEPTEMBER.SUSITNAHYDROELECTRICPROJECTFIGURE12PREDICTEDWINTERMAINSTEMSTAGESFORNATURALANDWoodward-ClydePROJECTFLOWSNEARTHEHEADOFSLOUGH21ConsultantsfIlXJ&~~~~[ID&~IUltTN4JounVENTU"E [- )L-JL.-Jl.L.L.)l-JJL~J(J1.-!!,-jeo,ooo....--....._..._.-..,-'.-40,000.,.".,.-~-..._.::'....':::1).::'iJ.-..---. .....,-.._. _._.•••••"0-.,...,.-....~1"\"T'I"'f,","1:':".'':'..'..m...,...::"H'H'H·HHU.30,000:'...,....~.'.:.:-.:::."".<.. ....--...-.~...•..••......J:....::...'.:..:.."':.:(J20,000. . . .:.'...,.~::::.'.::.. : .: .":..':'.:.::....:..:"t-.f:.f1:I:1..t.t!:..t:ll.."....,... ......,,.......~:I:~\i{E",;,'.'::.. . ....'1'::""';'»\:;:':'. '..:~:.:..::"..:..:.;..10,000~::.::..:~I""';~::•.•'~/:..'~",.'~_""::' ::.::..:..:.:~...'.''................'.:....,....:',..JfIlJ111.11ufIllll/IllI-'..-_.....:::.:.It\..'I:IJ.o. .JANFEBMARAPRMAYJUNJUlAUGSEPOCTNOVDECSIMULATEDMINIMUM,MAXIMUMANDMEANMONTHLYDISCHARGESFORALASKAPOWE'RAUTHORITYMAXIMUMPOWERCASEP-1COMPAREDWITHMINIMUMMAXIMUMANDMEANMONTHLYDISCHARGESFORNATURALCONDlTIONS.SUSITNAHYDROELECTRICPROJECTt:::i::::'YilAREAWITHINTHEBOUNDSOFTHESIMULATEDMINIMUMANDMAXIMUM:.::.'::::'.i;:!!.:MONTHLVDISCHARGESFORCASEP-1.n:rm1IAREAWITHINTHEBOyNDSOFTHEMINIMUMANDMAXIMUMMONTHLVWoo<JwardoCf't'&t~M~rD\"i'1~t::II~rm~.~I:tI:t:.I::t1JDISCHARGESFORNAURALCONDITIONSFOR33VEARSOFRECORD.lI\I[..:.lll\J~l5~~II••NATURALMEANMONTHLVDISCHARGE.~IUIITN4.I0lN1Y!N'UJltrII"...SIMULATEDMEANMONTHLVDISCHARGEFORCASEP-1.FIGURE13 LJLLIL)ll.JI»L.I.~)Jl.JJ',..~.."JLj1-~I-".;':-.:""0,00000,000i:-i"o'I:);::,:::(:{',::\:NOTE1.DISCHARQEFORSUSITNARIVERATGOLDCREEK2.NOMAXIMUMFLOWLIMITSWEREESTABLISHEDFORCASEC+.~~f~:72f7~Ttti~~7+~8T~1ttM~ml~~~*~~3.PERCENTPROBAJ)ILlTYOFEXCEEDENCECURVESDUAtN()wrnt-.:1:?~'::;":::.:.:.:O::j::r.:I:..'::::!:'i'..::.t"::':I::;::mt~rtIJ~PROJECTCONDIT10NS.PROBABILTYHL?::::::?':?:::::RfffimrmCURVESAREBASEDONWEEKLY;:.AVERAGEFLOWSFROM33YEARS...~~..p.~~~~~~~HmmHtlij-.;~~:;:;:.,..mmlt''fl''\OFSYNTHESIZEDPROJECT_~OPE~ATlON.(/).•..•..•,.:::••••.•.:::'.:•.'II.••u..'..;;;:..":o30,000..::'."...'..~:..:::'::'.;.':'::..:..:.:.:.~-.._.",..'..UJ.'.::"~;"...CJ.....:~.:,.'....~>:>:...:.....:520.000':•...:.•·C··..•••••.(/)..,.:.:"......:1~l.I-"I.·44:.I~J:.1-~;..,".-C.t.ttttflt.tl:H1fI++trl~~~::rl·10,000........"IH1U1T1Tllj.•.•••.•.rnnrrrtlt".'..'.-'",....oJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTMINIMUMANDMAXIMUMWEEKLYDISCHARGESFORCASECFLOWSCOMPAREDWITHMINIMUM,MAXIMUMANDMEANMONTHLYDISCHARGESFORNATURALCONDITIONS.I.:':::!!:;:::::IAREAWITHINTHEBOUNDSOFCASECINSTREAMFLOWREQUIREMENTS.IItl'.'!!1AREAWITHINTHEBOUNDSOFTHEMINIMUMANDMA.XIMUMMONTHLYl:l±l:WDISCHARGESFORNATURALCONDITIONSFOR33YEARSOFRECORD..)f)()cNATURALMEANMONTHLYDISCHARGES.FIGURE1..'Noodwcvd-ctydeConsultants~IXl&OO~C2~@&~IUIITNA.JOINTY[NTUJIII! LL)lLjJiLj.JJJI~J.JJL-.J_._,J•••000IIII1flTIffffflffII 1INOTEI Ir1.DUICHARGEFOR8USITHARIVERAT_OOLDCREEK.'.:"MAX:m1ft.tl.l<·,.....1.,.....··:.;:r.J:"'.lU:f:1Hlu:rLr'-.;'-;:.,1I1lTJllh:tttnutm:llltmt:f.fHfl:J-I-iil:IIltnt···~t'tll:\:l:.•.•.JI I I..•.."':Ii·.··ill.••....jI'0,0"nH[•••••!".•.•.....••.••..·1I40.00~I I I IIIffiiJIJI I It.o,ooo~I 1I··_LlJ"a:c::co(1)-Q......tIJU.o.....,ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoocfward.CtydeConsultants"lXJ£ffJ~I::'§lID&~aualTN4JOINTVfHTUIliEo."ANFE!MARAPRMAY"UN"Ul.-MINIMUMANDMAXIMUMWEEKLYDISCHARGESFOReASEEVFLOWSCOMPAREDWITHMINIMUM,MAXIMUMANDMEANMONTHLYDISCHARGESFORNATURALCONDITIONS.[1':::::;::::::.:(:;1AREAWITHINTHEBOUNDSOFCASEEVINSTREAMFLOWREQUIREMENTS.ffffffIAREAWITHINTHEBOUNDSOFTHEMINIMUMANDMAXIMUMMONTHLYl::l:±±±±:IDISCHARGESFORNATURALCONDITIONSFOR33YEARSOFRECORD.~~NATURALMEANMONTHLYDISCHARGES.FIGURE16AUOSEPOCTHOVDEC ~;~c-lc-J[')lJc-c=-Jr~l[jlJC-JJ[-Jr-,l--]l -][-Jr1,l.,\..J60,000.1.11'NOTE1.DISCHARGEFORSU81TNARIVERATGOLDCREEK.0,oooJI I I I~I:JI I ItJ:J:LU........I.I.......................;0•••_...:1:,.•.•<I-l.j,·I"l'l:!"·".MAX·.~~1;~~f~"'.:::Illftl~.....~10,000.....-.,..,.;:...,..'".:....: ::~........'..::...-..;:::'.'::.,:'~LN~~C:~~~~~~OllliU11mttrim'~:OO~mt~rJ;;;;;2d30,000I..,..'.<:::,'::'.'0;••:::.:".•':"•.:.......,>'/";'yI_._>._-:".:-.----....::...:Il:rHFllllH-120,OOO~I I I'<"d"1IL;:,,',.tJ,::UJ"a:<:x:o(J)-a-(JJLLo....,.::""',":':::.:.::',1!flltH-fllil.-MINo 'IiIIII,IJANFEDMARAPRMAYJUNJULAUGSEPOCTNOVDECALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTMINIMUMANDMAXIMUMWEEKLYDISCHARGESFORCASEEV1FLOWSCOMPAREDWrrt1MINIJIUM,MAXIMUMANDMEANMONTHLYDISCHARGESFORNATURALCONDrrIONS.(\'\:\:j'\::i\::@:\:::lflAREAWITHINTHeBOUNDSOFCASEEV1INSTREAMFLOWREQUIREMENTS.m::r.n::lIAREAWITHINTHEBOUNDSOFTHEMINIMUMANDMAXIMUMMONTHLYttttttIJDISCHARGESFORNATURALCONDITIONSFOR33YEARS.OFRECORD.M)(M.NATURALMEANMONTHLYDISCHARGES.FIGURE16Woodward-ctvdeConsultants~OO&OO~ca~@D:l~.UltlMAJOINTYENlU"! (--")r-lLJr--:JrJ["jc--JLJc-Jc-Jc-Jc-Jc-JLJLJLJL)C~c-l50,000IiiiIIIIIIINOTE1.DISCHARGEFORSU8iTNARIVERATGOLDCREEK40,000I I I I I I I I I I I I I30,000L_-.l---I---.j~-~---+8;±f~+.7+.2::+:7~±~~+---r---r---rII ,",.N·t!I.jI;rnnu.T.t;S;~±;::Hmffiffihffimmm*MAX..-(JJ1Lo......we"a:~:x:oCJ)-QoIII I I I I IIIII,JANFEBMARAPRMAYJUNJULSIMULATEDMINIMUM,MAXIMUMANDMEANMONTHLYDISCHARGESCOMPAREDWrrHMINIMUMANDMAXIMUMWEEKLYDISCHARGESFORCASEEV1INSTREAMFLOWREQUIREMENTS.AREAWITHINTHEBOUNDSOFTHESIMULATEDMINIMUMANDMAXIMUMMONTHLYDISCHARGESFORCASEEV1.ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoodward-CJvdeCQnsultants~DECNOVlXJ&rtJ~ca~[ID&~IUI"H".I0IHTY(HTU"!OCTS;,;PAUGFIGURE17AREAWITHINTHEBOUNDSOFCASEEV1INSTREAMFLOWREQUIREMENTS.SIMULATEDMEANMONTHLYDISCHARGEFORCASEEV1.III-1(OJ('l( STREAFLOW~+--WINGDEFLECTORWALLS...--4--LARGECOBBLEFILL..2'TYP~MODIFIEDLIWIDTHr....TPASSAGEREACH--ORIGINALWIDTH-'"""tlI,'-FIGURE18WINGDEFLECTORALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTNOTTOSCALE[}{)~~~c.~~~BUIlTH"JOINTvtNTU"t LlIJJL.Jlj .lJ'\/FLOW-~OLPOOL)III~PASSAGEREACHr-SIDEVIEWPASSAGEREACH----~FLOW0----:.-00o0POOL00POOL6~00--40EXPOSEDROCKSPLANVIEWALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECT'Noodward-CWde1Xl&~~~rn@&~FIGURE19TYPICALPASSAGEREACHOFSLOUGHALONGC«lsuitants()MIDDLESECTIONOFTHESUSITNARIVERaUsITH4JOINTVl:HTUAE ...---lr-:r"lr-J'r--lr---"\,.r-Jc--Jc-lrJ..---,r-....,t}"'l_Jr---;'.).r---J;---.,,LJ..------.l'~..---...',__---'~'lJHEIGHTOFMAXIMUMSLOUGHDISCHARGE~ORIGINALCHANNEL,--JIt'7ROCKGABIONS, •EMBEDDEDINCHANNELBANKSFIGURE20ROCKGABIONCHANNELALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTNOTTOSCALEWoodward-CfydeConsultants~IXJ&OO~e2rnrID&~aUIITN4JOIHTYENTU,.( .''11'"FLOW-NOTCHTOPROVIDEEASEINFISHPASSAGEI.REBARREINFORCINGANCHORGABIONBARRIER_.J-:.....FLOW-r5-CONCRETEHIGHWAYCURBI.REBARANCHOR_--4-;~--,szHIGHWAYCURBBARRIERszROCKSILl.aARRlERFLOW'--...NATURALOEFTHOFFLOWTYPICALSLOPEPOOLANDWEIRSTRUCTURECREATIONOFPOOLSBETWEENBARRIERSALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECT-.J.--,FIGURE21GABIONBARRIERHIGHWAYCURBBARRIERROCKSILLBARRIERPOOLANDWEIRSTRUCTURENOTTOSCALEWoodward-CtydeConsultants~[XJ~~~=rn®&~!USIUU,JOINTV£NTUJi'[ <LLLL__/L.Jl_II......J).JJ.JIi==t:1CFSr'--'TOPRV2'BERMAT604FT.3'CONCRETECOLLECTORSYSTEM2'x4'x18'__2..-IT.................GRILLOF,STEELBAR...1/4x2-AND+4REBARSATURATEDWATER____\7-:AB~SURFACE--.........MAINSTEMELEVATIONAT600FT.20'ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTFIGURE22COLLECTORSYSTEMATSLOUGH9NOTTOSCALEWoocfward.CIydeConsultants~[}{)&OOtl&e:t~[ID&~8USITNAJOINTYENTU"! I1...._'-'-....-.-----.-I}LJ(,LJl.L..'1j~~z~..~W.JWW::>a:...60S500~590~,I;"1~...,...'-,;;.-''.,........_-;'u••,••(!l•••,.TA\.--,'.....-/.".~.....,'\...y,_~,li/,,-( ).,(OUTLET.-J;.:o(/1l:'Y\/;,/.~._-!!;~::.~:://~-..~Jt/..JJ:=='.-----.o.t'lO,l"t'";';.·....~...............""'-..;.'StOUGH9-'or'[)r"o~,o,••.0ST~(~..ftrun,'lot.USU.'IOIlOUTLETSTRUCTUREOFCOARSEGRAVELSANDCOBBLESl'DEPTH~!SO.OOO',•!.!t!.OO,"",'OO,h",'00'"~,._~~.O.~ff'(P':.-"'=CC;-C:b~·'..':-'','__:.l:",~..rArt";;(:~...r..11ft:-w~SLOUGH9PASSAGEREACHLOCATIONSc:::JsouISANDCDGRAVELIRU88LE~COBBLEIBOULDER-..PASSAGEREACN,CORRUGATED'METALPIPECOLLECTORSYSTEMLl-:..JLII.-lIUI:1.'~r--1r---,I....--:Ht--l~oJr·----,.--·-.,.--•i•i•.1000,'.00".00:>00010000I~lOoOOl:loOO300005:>000400004:>000500005:>00050000~TREAMe[OFIGURE23THALWEGPROFILEOFSLOUGH9ALA'SKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoodW'ard-aydeConsultants~'c<J&rro~~rnOO&OOQ)IUIITN"JOINTY[HfUJII( r-----!cL~J-J,--1,r-,lJr--,"'c-lr--rl',----,J'~Jc-=JSLOUGHIISTREAMBEDEJ'AOflLl$TUO'"Ill"A"A["WU[O""TIO"6&:16110-••-z0t=6U<l>....oJ........~6'10tooiii:'SLOUGH11SURFACESUBSTRATETYPESo$ILT1$""0oCi""lIlLIIlU_~Lt~COULlIUOULOUUUU'''~"11ltAIll~CltCiIl~OltH"'o.,,,,,,,,~20',COLLECTORSYSTEM660I ,IIII,,IIIII-lOtOO-:"000.00:"0010too1:'10020tOO2:ltOO~O'OO~:"OO40'004~'OO:.0'00STRfAMBEOSTATIONFIGURE24THALWEGPROFILEOFSLOUQH11ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoodward-Cty&ti".U-nts~n,>''-'UtAUI"d-W[}{)&ootz&c»rnOO&~aUSITHAJOINTYfNTUAE [-.-jc--;r--1l,r-,~,j~[---:JC--J[-JC-Jr--;l..)r-J!)CJLJc-J[~,~~"!:?....>140....J...J...::>IE..1!loOf4Susno/1•...._--OUTLET'....".";>'<::::,r-.,'''H''..--I-~~~..•.•::::':.~....:;~•." .~~NK...._,....,""...'..-,...~'1..-":t:t'-!!.!'~II::':L~:U~:::::~~.u1""'0tIOUTLETSTRUCTUREOFCOARSEGRAVELSANDCOBBLESl'DEPTHw~~SLOUGH21COMPLEXPASSAGEREACHLOCATIONS[==:JSILT'S"'"O£23DCOIIILl'lll/ttLl........""'SSUIIlfACMCOLLECTORSYSTEMMAIINSTEMr..,CiH'~"~"\i'"_:ttR• II...,rtr.....NI..~• •11.....P"4ll~iiiiiiiifi·I~'OO"10-00·'·000'005'0010'00l,tOO20'00I~OO30'00STREAMBEDSTATION1/01'1FIGURE26THALWEGPROFILEOFSLOUGH21ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECT~CIydeConsultantsQlXJ&rRl~r::t~®&~IUIITMAJOINTV[NTU"~ -1,,, ,\>-..JlL )ll,jlJj,,..)).J,,Jo0 0"0"0 0PERFPIPE6'O.C.CLEANOUTUNDERBED,COARSE(a-PLUS)GRAVEL2'0-t"cnl"t"1t"C-"'"'":'"-:-:::t,..I'ff~----'"iii6'O.C.WATER,.,' " ,-SUPPLYLINE,__20'WIDEBED..IMIN.WATERDEPTHI'e-(r--2-a-GRAVELSI \lYIWATER./SUPPLYLINE-./.SECTIONA-AFLOWCONTROLA,IL-WATERSUPPLYLINEA~IALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTI'ff,.,...RIVERSUSITNARIVERFISHERYMITIGATIONINDUCEDUPWELLINGUSINGTRIBUTARYWATERSUPPLYFIGURE26Woodward-aydeConsultants~lXJ&OO{Z&I::I~[ID&~IUIITNAJOINTYENTU"! I>)(,LL-JLJ)I -'cI -lJWEIRSTRUCTUREWITHNOTCHFORISHPASSAGEWATERFLOW~GOODORIGINALS~t~~~~Gc__vt:_~c[~--~c~--GROUNDWATER...NEW-SPAWNING-F1ABITATUPWELLING_.-///-/."IIMPERMEABLESECTIONFIGURE27WEIRTOINCREASESPAWNINGHABITATALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTNOTTOSCALEWoodward-CtydeConsultants(i)c•lXf&ootz&CJrn[ID&~IUIITH4JOINTVl:HTU,1j( nL..'-I...~....-'114'1--.....L.L.2"x4"CRO.SSBRACINGIMPERMEABLEMATERIAL(PLASTICLINER)ITIMBERPOSTS10"<j)~1.5'-1.....l...8I\"~~~"'\~~~~v8O· .Io--R1PRAPASSIDE~l,"\~PROTECTIONu,JNJVVV'~VJU\jroll\,..."""''''''~Io'r-ORIGINALCHANNELUI~~~_~~~_~,-,I[.[[I'~l_J~JI'L_...JI'L..I'FIGURE28TIMBERPOSTWEIRALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECT[[[;[l:[[[,.L...'FLOW~~NOTTOSCALEv~.PLASTICLINERIIII2"x."BRACING'Noodward-~Consultants~.~&rro~~~~~IUSlTM4JOIHTV£HfUPI! l.l~l.lII)lj(-jljL.)lJL)jjJ.)ROCK.GABIONSORIGINALCHANNEL1.1I II.)EXCAVATEDBANKTOPROVIDEI •FIRMSTRUCTUREEMBEDMENT-I--I---1---1---I---iL_L_L_L_L_I I I I I I---,--,--,-,-J.1'-+1:.j3+6REBARANCHORS+6REBARANCHORTYPNOTTOSCALE~FIGURE29ROCKGABIONWEIR---==PLYWOODSHEETSREINFORCINGBARSPAWNINGGRAVELALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoodward-ClydeConsultantsfjIlXJ&fFJtz&CI~[ID&~,a~SITNAJOINTY(NTUA! 'VFLOW-..~vREINFORCINGBARTOSTABILIZEPLYWOOD3'l-SIDEVIEW___.J_J--)LARGERROCKSEXCAVATIONTOEMBEDSTRUCTUREINCHANNELAfP.,eORIGINALCHANNEL--~CROSS-SECTIONFIGURE30ROCKWEIRALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTNOTTOSCALEWOocfward.OydeConsultantsca!Xl&OOt2.£C2~~~aUSlnUJOINTY£NTUR[ ~I!t-L~nL=LENGTHOFBERMPLANVIEW[[c~Iyn'=..-'"nLJ,-JIMPERMEABLECORENEWGRAVELFILLORIGINALBERM'CROSS-SECTIONALVIEWD=DEPTHOFEXCAVATIONFORIMPERMEABLECOREY=INCREASEDHEIGHTABOVEORIGINALBERM~-jFIGURE31BERMDESIGNTOPREVENTOVERTOPPINGOFSLOUGHSALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoodward-aydeConsultants"!Xl&~~={~~~aUSaT"."JOINTvtHTU~! r ALA'SKA POW -, '-SUSITNA HYDROE~~AUTHORITYTRICPROJECT 'Noodward-avde I - ConsuJtanb ~lXlLM~I~.",~@&~ IUIIT""JOI 0 I NT Y(NTU"( - iLOUGH EXCAVATtOH GRAVEL 6HRUSS - CHANNEL OUTUHE OUTUHE Of WETTr-:~~...:...::.~~~ED~SURfACE ARERAILROAD A AT MAINSTEM DISCHAR GE Of 12,500 C BEAVER DAM FS AT GOLD CREEJ( - 8 (_--lID~LOG BARRiER6 D WaR o PWE INLET AND OUTLEToBERM OWING DEFL£CTORS 50% ENTIRE SLOUGH $76,000 500 J 250, fEET SLOUGH 9A o, FIGURE 35 LOCA TIONS OF MITIGATION MEASURES AND PERCENT DISTRIBUTION OF SPAWNING CHUM SALMON DURING 1984 IN SLOUGH 11 AND UPPER SIDE CHANNEL 11. $150,000 ALA'SKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT Woodward-Ctyde ~~[frJ~~~[ID&~ Consultants " IUIITH"JOINT Y1NTU"( UPPER SIDE CHANNEL 11 $150,000 5% ENTIRE SLOUGH $26,000 I )]iiiiiiiiiiiii---z ~~~ I $30,000 500 I 250 I FEET SLOUGH 11 o BERM {J WING DEfLECTORS o I GRAVEl. FOREST SHRUBS SLOUGH EXCAVATIOH CHANNEL OUTUNE OUTUHE OF WETTED SURF~CE AREA AT MAjHSTEU DISCHARGe Of 12,600 CfS AT GOLD CREex RAiLROAD BEAVER DAM LOG BARRIERS G ~~ m LEQEHD: D W~ o PWE INLET AHa OUTLET ~ c{ ( 0 vXHINHdavL...IL..IL..J [rAPPENDIXAgroundwaterupwellingisrelatedtothemainstemdischarge(APA1984).PassageReachFlowEvaluationThelimitationsandapplicationsoftheseequationsarediscussedinthefollowingparagraphs.ApreviousanalysisestimatedtherequiredlocalflowforsuccessfulfishpassagethroughthepassagereachesofthesloughsalongtheInordertoAprimarycomponentofSloughRegressionEquationr28AS=-.629+.000128G.6329S=1.97+.000351G.80511S=1.52+.000102G.76521S=-7.55+.00105G.542groundwaterupwellingandsurfaceinflow.S=sloughflow(cfs)G=mainstemdischargeatGoldCreek(cfs)middlesectionoftheSusitnaRiver(ADF&G1984c).evaluatetheavailablelocalflowinSloughs8A,9,9A,11and21incomparisontotherequiredlocalflows,ananalysisofthelocalflowsourcesforeachsloughwasconducted.LocalflowiscomposedofTherelationshipsdevelopedfortheapparentgroundwaterupwellingcomponentofsloughflowattheR&MgagesitewithinthesloughversusmainstemdischargemeasuredatGoldCreekarelistedbelow(APA1984).TheequationforSlough8Apredictspoorlyatlowmainstemdischargesinceitwasdevelopedfromdatacollectedfrom6Junethrough7August1983whenthemainstemdischargewascontinuouslyinexcessof16,000cfs.Alowerlimitwasestablishedfortheequationbasedonanestimatedminimumbaseflow.Datafor1983recordaminimumsloughflowof0.8cfsinlateOctober;thebaseflowcomponentofthelocalflowwasassumedtobe75percentofthisvalue.Asloughflowof0.6cfscorrespondstoamainstemdischargeof9,000cfsinthe[[[[[[[cc[[[[[[[l~ r'-~[c'[[[[['[:c[[['r,L[[[[r-'"'-_'Iregressionequation.Thus,theestimatedbaseflowformainstemdischargeslessthan9,600cfsremainsconstantatthisminimumsloughflowof0.6cfs.ForSlough9,theequationwasdevelopedfortheperiodfrom21Mayto27October1983excludingthedateswhenthesloughflowwasgreaterthan8cfs,whichcorrespondstothemaximumsloughflowpriortobreaching.Sloughflowdatafor1982waslessthanthevaluesobtainedin1983.Theminimumsloughdischargemeasuredduring,thesummerof1982was1.5cfs,whileinthesummerof1983,theminimumsloughflowwas3.8cfs.Theequationdevelopedfor1983appearedtooverpredictsloughdischargeatlowmainstemdischarges.Inordertobeabletopredictlowgroundwatersloughflowsreflectingthelowlocalflowdatameasuredin1982,analternateequationwasdeveloped.Sloughflowversusmainstemdischargedatafor1982wereplotted(FigureAI).UsingaslopefortheregressionlineapproximatingtheslopedevelopedforSlough8AwhichwasassumedtobethesloughmostsimilartoSlough9,alinewasdrawnthroughthevaluescorrespondingtothelowestsloughflows.Aminimumgroundwatercomponentforthesloughwaschosentobe1cfs,whichisabout75percentoftheminimumrecordedflow.UsingtheselinesasshowninFigureAI,thegroundwaterflowatthegagewasobtainedforvariousmainstemdischarges.TheregressionequationforSloughilflowappearedtobeafairlyaccuratemeansofpredictingsloughflowscorrespondingtomainstemdischarges.Itwasbasedondatacollectedfrom25Mayto27October1983.AtSlough21,thecorrelationvalueof0.542forthesloughflowversusmainstemflowrelationshipisconsistentwiththepoorsloughdischargepredictionsatlowmainstemdischarges.Datafrom10Augustto22October1982wasusedtodeveloptheequation.Aminimumbaseflowwasestimatedtobe75percentoftheminimumsloughdischargerecorded;atlowmainstemdischarges,i.e.<8300cfs,thebaseflowcomponentofthelocalflowisassumedtobeconstantat1.2cfs. [rL-l[[f1lJ[[.JJL!~rL~L.....-OI~-"-'-"~'-"Withtheselimitationsinmind,theregressionequationswereusedtoestimatetheapparentgroundwaterupwellingcomponentoflocalflowattheR&Mgagesiteinasloughgivenamainstemdischarge.Inordertoobtaintheupwellingcomponentoflocalflowatotherpointswithintheslough,theamountsofupwellingthroughoutthesloughwereestimatedintermsofpercentofthegageflowusingaerialphotographs,observationsbyR&Mpersonnel(R&MConsultants,Inc.1982),andmeasuredupwellingvalues(APA1984andWCC1984).Thepercentagevalues(TablesA1-A4)wereappliedtothecalculatedflowatthegageresultinginestimatesoftheupwellingcomponentoflocalflowatpointscorrespondingtopassagereachesintheslough.ForSlough9A,measuredupwelling_valueswerecorrelatedwithmainstemdischargetoyieldtheupwellingcomponentoflocalflowatthepassagereaches.ForUpperSideChannelII,thebaseflowscorrespondingtoselectedmainstemdischargeswereestimatedateachpassagereach(ADF&G1984andADF&G1984d).SideChannel21wasassumedtobeahydraulicextensionofSlough21.Acomparisonbetweenrequiredlocalflowandestimatedavailableupwellingcomponentoflocalflowwasmadeateachpassagereach(TablesA5toA50).Anevaluationwasconductedofhowmuchofthetimethelocalflowrequirementscouldbesatisfiedbygroundwaterflowalone.Therequiredlocalflowwasinputtotherelationshipbetweensloughflowandmainstemdischargetoobtaintherequiredmainstemdischarge.Theflowdurationcurvedevelopedfortheperiod20Augustto20September(ADF&G1984c)forthemainstemdischargewasusedtoevaluatethepercentoccurrenceoftheseflows.Acombinationofsurfacewaterandgroundwatersourceswasanalyzedonthebasisoftheassumptionthatgroundwaterwasatalevelcorrespondingtotypicalmainstemflows.Fornaturalsloughflows,themainstemdischargeof50percentoccurrenceequalling15,000cfswaschosenasthebasisforgroundwaterflows.ProJectflowswereassumedconstantattheminimumrequiredflowsof8,000cfsor9,000cfsforCaseEVIand12,000cfsforCasesCandEV.Also,forCaseEV,theeffectofaspikeofmainstemdischargeof18,000cfsduringspawningwasevaluated.Ifthehighermainstemdischarge [[[[[[[c[I'L__[1-'"'-',-'---,-''---~-~,increasedthefrequencyofpassageoverthatavailablefortheminimumrequirementsof12,000cfs,thiswasindicatedinTablesAStoASO.Useofminimuminstreamflowrequirementsintheanalysisaddressespotentialimpactsduringlowtoaverageflowyearscomparedwithmediannaturalflows.Projecteffectsduringhighflowyearswouldbeless.Thepercentoftimethattributaryinflowwassufficienttosupplementgroundwaterwasbasedonanestimateofthecontributingbasinarea,anassumedrunoffpercentageof40percent,andprecipitationdurationcurvesforTalkeetnafortheperiodof1972to1981(TablesAStoASO).Thepercentoccurrenceofsuccessfulpassageforpassagereachesaffectedbybackwaterandbreachingwaspreviouslyanalyzed(ADF&G1984c).Thefinalvalueselectedforeachpassagereachwasthelargestpercentsuccessfulpassageoccurrencevalueofthosecalculated(TablesAStoASO).Passagereachesimpactedbyadecreasein.mainstemflowareidentifiedbysignificantdecreasesinpercentsoccurrencebetweennaturalandprojectflows.Anyadditiveeffectsofaccumulationofpercentoccurrenceswereassumednegligible. [:c-lr-Jr--:!~C---Jc-:Jc-Jc-lc--JJLJ-)SLOUGH910-NOTES=SlOUGHDISCHARGEG=MAINSTEMDISCHARGEATGOLDCREEK.-e•~ee••.&1• • e•&&&8-~gw~,....c5(J)is:rCl:lo4-...I(QS=1.97+.000351G&&•. .~__6•8&&&&&&.S:::0.11+.00013GIoI I I I I I III I I Ia468188101112131415MAINSTEMDISCHARGEATGOLDCREEK&&~8~'L--====---C:J.DATAfOR1882•DATAf'OR1883FIGUREA 1IDENTIFICATIONOFRELATIONSHIPBETWEENSLOUGHDISCHAR(~EANDMAINSTEMDISCHARGE.ALASKAPOWERAUTHORITYSUSITNAHYDROELECTRICPROJECTWoodwardoClydeConsultants"OO£OOtz&e:t~~~aUIITN4JOINTV(NTu"t [[[[[[[[[[[[IlJr~'Lr~~'LJ[TableAI.PercentgroundwaterrelativetogageflowatpassagereachesinSlough8A.PassageReachPercentofGageFlowI103II101III101IV60V52VI43VII35VIII25IX15 [[-~~j[-[TableA2.PercentgroundwaterrelativetogageflowatpassagereachesinSlough9.[[[c[c[[[[[l~.>PassageReachIIIIIIIVVPercentofGageFlow1241171009577 -,~TableA3.PercentgroundwaterrelativetogageflowatpassagereachesinSlough11.PassageReachPercentofGageFlowI145II127III102-"IV97--,V65_1---'-'~J -.,,--..Jt~TableA4.Percentgroundwater~elativetogageflowatpassagereachesinSlough21andSideChannel21. [[[TableAS.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachI.21.4o0.6o2525.0321.425aa0.625.0321.127a100100b0.9.02MainstemflowatGoldCreek(cfs)21.379Naturalft1200090008000Requiredflow(cfs)Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow%Exceededbasedontotaldailypptandgroundwater32Surfacewaternecessaryforpassage(cfs)0.7Amountofpptneededforbasin~reaof1.36mile2(in).01Ba~kwater%exceededformainstemdischargeof<10,600cfs79Groundwater&SurfacewaterBreaching%exceededforcontrollingdischargeof27,000cfs7Maximum%exceeded[[[[[[[[[,-,I[1--'LJaNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIbybackwatereffectsI'IL....4i [[-I-,[[[[[[[I'I''--'-,.....-j~J!TableA6.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSloughSAforPassageReachII.MainstemflowatGoldCreek(cfs)Naturala120009000SOOOGroundwater&SurfacewaterRequiredflow(cfs)4c444Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow1.3.9.6.6Surfacewaternecessaryforpassage(cfs)2.73.13.43.4Amountofpptneededforbasinareaof1.36mile2(in).05.05.06.06%Exceededbasedontotaldailypptandgroundwater19IS1616Breaching%exceededforcontrollingdischargeof27,000cfs7000Backwater%exceededformainstemdischargeof15,600cfs4S000Maximum%exceeded4SlSb1616aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G19S4c)bForCaseEV,themainstemdischargeperiodoflS000cfswillassistpassagethroughPRIIbybackwatereffectscRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPR •......J--_.'In~--',--'.,-j,-'"TableA7.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachIII.MainstemflowatGoldCreek(cfs)Natural~1200090008000Groundwater&SurfacewaterRequiredflow(cfs)4444Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow1.3.9.6 .6Surfacewaternecessaryforpassage(cfs)2.73.13.43.4Amountofpptneededforbasinareaof1.36mile2(in).05.05.06.06%Exceededbasedontotaldailypptandgroundwater19181616Breaching%exceededforcontrollingdischargeof27,000cfs7000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded1918b1616~aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIIdBreachingoccurspriortobackwatereffects [[:r·'L_"[[[[:[[['-,[--.'"l-'.J[['[[r-·'~-jC'!L;r~il-JTableAS.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSloughSAforPassageReachIV.MainstemflowatGoldCreek(cfs)Naturala120009000SOOOGroundwater&SurfacewaterRequiredflow(cfs)5c555Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow.S.5.4.4Surfacewaternecessaryforpassage(cfs)4.24.54.64.6Amountofpptneededforbasinareaof1.09mile2(in).09.1.1•1%Exceededbasedontotaldailypptandgroundwater10S77Breaching%exceededforcontrollingdischargeof33,000cfs2aaaBackwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded10Sb77aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G19S4c)bForCaseEV,themainstemdischargeperiodoflS,OOOcfswillnotassistpassagethroughPRIVcRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRdBreachingoccurspriortobackwatereffects hr,L~TableA9.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breaching"flowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachV.~MainstemflowatGoldCreek(cfs)Naturala1200090008000~'--,~--",--"_oj=,;iGroundwater&SurfacewaterRequiredflow(cfs)5555Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow.7.5.3.3Surfacewaternecessaryforpassage(cfs)4.34.5 4.7 4.7Amountofpptneededforbasinareaof1.09mile2(in).09•1.1•1%Exceededbasedontotaldailypptandgroundwater9877Breaching%exceededforcontrollingdischargeof33,000cfs2000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded98b77aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18,000cfswillnotassistpassagethroughPRVdBreachingoccurspriortobackwatereffects-~jj [[[[[[r-~'.......[ur·"',,--'TableAI0.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachVI.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)4444Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow.6.4.3.3Surfacewaternecessaryforpassage(cfs)3.43.63.73.7Amountofpptneededforbasin~reaof1.09mile2(in).08.09.09.09%Exceededbasedontotaldailypptandgroundwater121099Breaching%exceededforcontrollingdischargeof33,000cfs2000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded12lOb99aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVIcRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRdBreachingoccurspriortobackwatereffects [[[TableAll.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachVII.[MainstemflowatGoldCreek(cfs)Natural~1200090008000Groundwater&SurfacewaterRequiredflow(cfs)4c444Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow.5.3.2.2Surfacewaternecessaryforpassage(cfs)3.53.73.83.8Amountofpptneededforbasin~reaof.96mile2(in).08.09.09.09%Exceededbasedontotaldailypptandgroundwater111099Breaching%exceededforcontrollingdischargeof33,000cfs2000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded11lOb99[[[[[[[.[[aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVII[cRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPR[~dBreachingoccurspriortobackwatereffects[[[L....j [[[I'l._,;'TableA12.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachVIII.MainstemflowatGoldCreek(cfs)Natural~1200090008000Groundwater&Surfacewater-..0r't-..,:...........;JRequiredflow(cfs)Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflowSurfacewaternecessaryforpassage(cfs)4.33.74.23.84.23.84.23.8Amountofpptneededforbasinareaof.55mile2(in).16%Exceededbasedontotaldailypptandgroundwater4..164.164.164-c-~Breaching%exceededforcontrollingdischargeof33,000cfsBackwater%exceededformainstemdischargeofdcfsMaximum%exceeded2d4od4bod4od4--'aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVIIIdBreachingoccurspriortobackwatereffects [[[TableA13.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges.breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough8AforPassageReachIX.[Natural~1200090008000Maximum%exceeded2Amountofpptneededforbasinareaof0mile2(in)e%Exceededbasedontotaldailypptandgroundwater04.1o3.9oedo4.1oe3.9ood4• 1eo3.9odObMainstemflowatGoldCreek(cfs)4Requiredflow(cfs)Surfacewaternecessaryforpassage(cfs)3.8Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow.2Backwater%exceededformainstemdischargeofdcfsdBreaching%exceededforcontrollingdischargeof33,000cfs2Groundwater&Surfacewaterr'L,[[[[[[[[[[laNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIXdBreachingoccurspriortobackwatereffects[eNotpossible,basinareaisinsufficienttoprovidesurfacerunoff[L [[[TableA14.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9forPassageReachI.[[MainstemflowatGoldCreek(cfs)Natural~1200090008000Amountofpptneededforbasinareaof2.99mile2(in)0Surfacewaternecessaryforpassage(cfs)0%Exceededbasedontotaldailypptandgroundwater100Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.621.5.00444.521.647.003.4.2o100o2.12Requiredflow(cfs)Groundwater&Surfacewaterno[[[[Breaching%exceededforcontrollingdischargeof19,000cfs29Backwater%exceededformainstemdischargeof<12,200cfs70[[.-,Maximum%exceeded100oa100boo47oo44~l-'aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIbybackwatereffects1-'ul-J'_.,'-' ~TableA15.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9forPassageReachII.-..,_._J.-..,MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)1111-,Groundwaterbaseflow(cfs)-Jcorrespondingtospecifieqmainstemflow2.52.01.51.4Surfacewaternecessaryforpassage(ds)0000,Amountofpptneededforbasinareaof1.73mile2(in)0000-,%Exceededbasedontotaldailypptandgroundwater100100100100-,Breaching%exceededforcontrollingdischargeof19,000cfs29000Backwater%exceededformainstemdischargeof"dcfsddddMaximum%exceeded100lOOc100100.~aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIdBreachingoccurspriortobackwatereffects--" TableA16.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9forPassageReachIII.-,MainstemflowatGoldCreek(cfs)Natural~1200090008000-,-J.-,-"~.,,~Groundwater&SurfacewaterRequiredflow(cfs)6666Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.11.71.31.2Surfacewaternecessaryforpassage(cfs)3.94.34.74.8Amountofpptneededforbasinsreaof1.]3mile2(in).05.06.06.06%Exceededbasedontotaldailypptandgroundwater18161514Breaching%exceededforcontrollingdischargeof19,000cfs29000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded2916b1514aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIII--'dBreachingoccurspriortobackwatereffects TableA17.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9forPassageReachIV.~MainstemflowatGoldCreek(cfs)Naturalft1200090008000Groundwater&SurfacewaterRequiredflow(cfs)6c666Groundwaterbaseflow(cfs)-.Jcorrespondingtospecifiedmainstemflow2.01.61.21.1-,Surfacewaternecessaryforpassage(cfs)4.04.44.84.9.,Amountofpptneededforbasingreaof1.73mile2(in).05.06.06 .07-"""'\%Exceededbasedontotal~dailypptandgroundwater17161414rBreaching%exceededfor~-'controllingdischargeof19,000cfs29000[Backwater%exceededformainstemdischargeof-~dcfsddddMaximum%exceeded2916b1414I~L_--,[aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIV[[cRequiredflowestimatedassumingthatrequiredflowatdownstreamPRissufficientforpassageatupstreamPRdBreachingoccurspriortobackwatereffectsr~LL [[[[[[[[[[[[IuTableA18.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9forPassageReachV.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)6c666Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow1.61.31.00.9Surfacewaternecessaryforpassage(cfs)4.4 4.755.1Amountofpptneededforbasinareaof0mile2(in)eeee%Exceededbasedontotaldailypptandgroundwater0000Breaching%exceededforcontrollingdischargeof19,000cfs29000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded29Ob00aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVcRequiredflowestimatedassumingthatrequiredflowatdownstreamPRissufficientforpassageatupstreamPRdBreachingoccurspriortobackwatereffectseNotpossible;basinareaisinsufficienttoprovidesurfacerunoff -,TableA19.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachI.MainstemflowatGoldCreek(cfs)Natural~1200090008000..,Groundwater&SurfacewaterRequiredflow(cfs)1111Groundwaterbaseflow(cfs)correspondingtospecified-,mainstemflow43.5 3.13.0-1Surfacewaternecessaryforpassage(cfs)a a a a-,Amountofpptneededforbasinareaof2.27mile2(in)aaa a-,%Exceededbasedontotaldailypptandgroundwater100100100 100-,Breaching%exceededforcontrollingdischargeoffcfsffffBackwater%exceededformainstemdischargeoffcfsffffMaximum%exceeded100100100100aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIaccordingtoexistingdata~fNodataavailable [~[[[I'L_"[[[r'L->[[I'l...~1-'L....>'TableA20.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachII.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)3333Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow3.93.43.02.5Surfacewaternecessaryforpassage(cfs)a aa.5Amountofpptneededforbasinareaof2.27mile2(in)a a a.005%Exceededbasedontotaldailypptandgroundwater10010010041Breaching%exceededforcontrollingdischargeoffcfsffffBackwater%exceededformainstemdischargeoffcfsffffMaximum%exceeded100100b10041aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIaccordingtoexistingdatafNodataavailable r~_..I[[TableA21.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachIII.MainstemflowatGoldCreek(cfs)Naturalft1200090008000Groundwater&SurfacewaterRequiredflow(cfs)3333Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow3.73.22.82.0Surfacewaternecessaryforpassage(cfs)a a.21.0Amountofpptneededforbasinareaof.35mile2(in)a a.01.07%Exceededbasedontotaldailypptandgroundwater1001003214Breaching%exceededforcontrollingdischargeoffcfsffffBackwater%exceededformainstemdischargeoffcfsffffMaximum%exceeded100100b3214bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIIaccordingtoexistingdataaNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)[[[[[[[[[[[[[[[[fNodataavailable I'L_[r-'II_JTableA22.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachIV.MainstemflowatGoldCreek(cfs)Natural~1200090008000aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIVaccordingtoexistingdatafNodataavailable->~ ![I'1-'u[Iu---'r-.uLJ·r"ILJ'---'TableA23.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachV.MainstemflowatGoldCreek(cfs)Naturala120009000.8000Groundwater&SurfacewaterRequiredflow(cfs)2c222Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.92.4 2.01.6Surfacewaternecessaryforpassage(cfs)aaa.4Amountofpptneededforbasin-areaof.21mile2(in)aaa.04%Exceededbasedontotaldailypptandgroundwater10010010020Breaching%exceededforcontrollingdischargeoffcfsffffBackwater%exceededformainstemdischargeoffcfsffffMaximum%exceeded100100b10020aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVaccordingtoexistingdatacRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRfNodataavailable LjTableA24.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingf'flowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachVI.MainstemflowatGoldCreek(cfs)Naturale1200090008000Groundwater&SurfacewaterRequiredflow(cfs)2c222r~~Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.72.21.81.5Surfacewaternecessaryforpassage(cfs)aa.2.5[Amountofpptneededforbasin~reaof.17mile2(in)aa.03.06%Exceededbasedontotal~:..'dailypptandgroundwater1001002414Breaching%exceededforcontrollingdischargeoffcfsffffL.~JBackwater%exceededformainstemdischargeoffcfsffffMaximum%exceeded100100b2414aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVIaccordingtoexistingdatacRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRfNodataavailable I'[[[[[[[[[[[[I~L[[[LI'LTableA25.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachVII.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)2c222Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.41.91.51.3Surfacewaternecessaryforpassage(ds)a.1.5.7Amountofpptneededforbasinareaof.13mile2(in)a.02.09 .13%Exceededbasedontotaldailypptandgroundwater10040107Breaching%exceededforcontrollingdischargeoffcfsffffBackwater%exceededformainstemdischargeoffcfsffffMaximum%exceeded10040b107aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVIIaccordingtoexistingdatacRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRfNodataavailable "nTableA26.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingnflowsandbackwatereffectsfortheperiodof20Augustto20September.atSlough9AforPassageReachVIII.L~[MainstemflowatGoldCreek(cfs)Natural~1200090008000~L.;~Groundwater&SurfacewaterRequiredflow(cfs)2c222nSurfacewaternecessaryforpassage(cfs)aGroundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow!L2.31.8.21.4.61.2.8~Amountofpptneededforbasinareaof.10mile2(in)a.0514.19n_~%Exceededbasedontotaldailypptandgroundwater1003163L.;Breaching%exceededforcontrollingdischargeoffcfsffffr-,L.-,Backwater%exceededformainstemdischargeoffcfsMaximum%exceededf100f31bf6f3aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVIIIaccordingtoexistingdata~cRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRfNodataavailable~ .--..,I1__,TableA27.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachIX.[MainstemflowatGoldCreek(cfs)Natural~1200090008000IGroundwater&Surfacewaterl.Requiredflow(cfs)2222!Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.11.61.31.1[Surfacewaternecessaryforpassage(cfs)a.4.7.9nL.JAmountofpptneededforbasinareaof.08mile2(in)a.12.20.25r%ExceededbasedontotalIUdailypptandgroundwater1002432[Breaching%exceededforcontrollingdischargeoffcfsffff[Backwater%exceededformainstemdischargeoffcfsfff.cr~LMaximum%exceeded10024b32bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIXaccordingtoexistingdataI'L...aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)[[fNodataavailable[r-L IL--.J[TableA28.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough9AforPassageReachX.[MainstemflowatGoldCreek(cfs)Naturala1200090008000r--,,Groundwater&SurfacewaterRequiredflow(cfs)3333Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow0000~Surfacewaternecessaryforpassage(cfs)3333'-"Amountofpptneededforbasinareaof.02mile2(in)eeee"1e-l%Exceededbasedontotaldailypptandgroundwater0000"Breaching%exceededfor~Jcontrollingdischargeoffcfsffff,-",'-"'Backwater%exceededformainstemdischargeoffcfsffff--"Maximum%exceeded0Ob00-"aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRXaccordingtoexistingdataeNotpossible,basinareaisinsuffi;ienttoprovidesurfacerunofffNodataavailable---"---.3 -_.->..,TableA29.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20~ugustto20SeptemberatSlough11forPassageReachI.MainstemflowatGoldCreek(cfs)Natura181200090008000-~"'Groundwater&SurfacewaterRequiredflow(cfs)4444Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow4.53.9 3.53.3Surfacewaternecessaryfor_passage(cfs)a.1.5•7~-o'Amountofpptneededforbasin·areaofamile2(in)eeee%Exceededbasedontotaldailypptandgroundwater7050a0Breaching%exceededforcontrollingdischargeof42,000cfs1aa a------"~JBackwater%exceededformainstemdischargeof-~16,200cfs44a a0Maximum%exceeded70SOba0--'----,aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)~bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIbybackwatereffectseNotpossible,basinareaisinsufficienttoprovidesurfacerunoff--' [[I'l-_...iTableA30.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough11forPassageReachII.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&Surfacewater~,~'-~.,Requiredflow(cfs)Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflowSurfacewaternecessaryforpassage(cfs)43.9. 143.4.643.01.042.92.1Amountofpptneededforbasin'areaof0mile2(in)eeee~%Exceededbasedontotaldailypptandgroundwater432000-,Breaching%exceededfor......controllingdischargeof42,000cfs1000-"Backwater%exceededfo~mainstemdischargeof33,100cfs2000Maximum%exceeded4320b00aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIeNotpossible,basinareaisinsufficienttoprovidesurfacerunoffJ-" "lc,~~-'0-",-..ilTableA31.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough11forPassageReachIII.MainstemflowatGoldCreek(cfs)Naturala1200090008000aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIIeNotpossible,basinareaisinsufficienttoprovidesurfacerunoff/' ,~-,TableA32.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough11forPassageReachIV.MainstemflowatGoldCreek(cfs)Naturala1200090008000-,aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIVdBreachingoccurspriortobackwatereffectseNotpossible,basinareaisinsufficienttoprovidesurfacerunoffr,.....J(;.-~ [[[[[[[[[[[[.......;6r--~L..il"-'---,__.J~---.o..iTableA33.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough11forPassageReachV.MainstemflowatGoldCreek(cfs)aNatural1200090008000Groundwater&SurfacewaterRequiredflow(cfs)4444Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow2.01.71.61.5Surfacewaternecessaryforpassage(cfs)2.03.33.43.5Amountofpptneededforbasinareaof0mile2(in)eeee%Exceededbasedontotaldailypptandgroundwater0000Breaching%exceededforcontrollingdischargeof42,000cfs1000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded1Ob00aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRVdBreachingoccurspriortobackwatereffectseNotpossible,basinareaisinsufficienttoprovidesurfacerun~!~----;:;/~j...~~.:--;)p...-'.&',.r..7.~~.'(~/~~~[~/y~/.~"J1,c'/AF';/:r., --,~~l-.3TableA34.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdisGharges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatUpperSideChannel11forPassageReachI.aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIbybreachingeffectsdBreachingoccurspriortobackwatereffects I'1__--'1[:TableA35.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatUpperSideChannel11forPassageReachII.MainstemflowatGoldCreek(cfs)Naturala1200090008000[I'L~Amountofpptneededforbasinareaof0mile2(in)e%Exceededbasedontotaldailypptandgroundwater0Surfacewaternecessaryforpassage(cfs)6Groundwaterbaseflow.(cfs)correspondingtospecifiedmainstemflow61275eo7125eo712oe512Requiredflow(cfs)Groundwater&Surfacewater[[['l[[[Breaching%exceededforcontrollingdischargeof16,000cfs45Backwater%exceededformainstemdischargeofdcfsdMaximum%exceeded45odObodoodo[E[[,[[aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIIbybreachingeffectsdBreachingoccurspriortobackwatereffectseNotpossible;basinareaisinsufficienttoprovidesurfacerunoff r--,rl"TableA36.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatUpperSideChannel11forPassageReachIII.""MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)12c1212121Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow3222.,-'Surfacewaternecessaryforpassage(ds)9101010.''1Amountofpptneededforbasin-areaof0mile2(in)eeee.,%Exceededbasedontotaldailypptandgroundwater0000.,Breaching%exceededforcontrollingdischargeof16,000cfs45000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded45Ob00aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIIIbybreachingeffects--J-'cRequiredflowestimatedassumingthatrequiredflowatdownstreamPRissufficientforpassageatupstreamPRdBreachingoccurspriortobackwatereffectseNotpossible;basinareaisinsufficienttoprovidesurfacerunoff ~lro~!L~TableA37.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingrflowsandbackwatereffectsfortheperiodof20Augustto20Septemberl>atSlough21forPassageReach1.IMainstemflowatGoldCreek(cfs)Natural~1200090008000"l.-~l_JI',--,in,..,I---c.........4Groundwater&SurfacewaterRequiredflow(cfs)5555Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow106.22.31.1Surfacewaternecessaryforpassage(cfs)002.74.9Amountofpptneededforbasinareaof.52mile2(in)00.12.22%Exceededbasedontotaldailypptandgroundwater10010064Breaching%exceededforcontrollingdischargeof25,000cfs10000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded100100b64aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)L.;ibForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIdBreachingoccurspriortobackwatereffects!l~r--"L~ ..,..,'-'TableA38.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough21forPassageReachIlL•..,.__JMainstemflowatGoldCreek(cfs)NaturalB:1200090008000,_..;J.-------,Groundwater&SurfacewaterRequiredflow(cfs)5555Groundwaterbaseflow(cfs)correspondingtospecified..,mainstemflow2.91.80.70.3Surfacewaternecessaryforpassage(cfs)2.13.24.34.7~__iJAmountofpptneededforbasinareaof0mile2(in)eeee.',%Exceededbasedontotaldailypptandgroundwater0000Breaching%exceededforcontrollingdischargeof25,000cfs10000'"--'Backwater%exceededformainstemdischargeof,dcfsdddd'--"Maximum%exceeded10Ob00aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIlLL....;i,~,.k..Ji-"dBreachingoccurspriortobackwatereffectseNotpossible;basinareaisinsufficienttoprovidesurfacerunoff --,TableA39.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingr'flowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSlough21forPassageReachIIR."iMainstemflowatGoldCreek(cfs)Naturalft1200090008000,-.Groundwater&.SurfacewaterRequiredflow(cfs)5555Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow3.22.00.70.4.,Surfacewaternecessaryforpassage(cfs)1.83.04.34.6,Amountofpptneededforbasinareaof.26mile2(in).16.27.39.41%Exceededbasedontotaldailypptandgroundwater4211"Breaching%exceededforcontrollingdischargeoffcfsffff"Backwater%exceededformainstemdischargeoffcfsffff~.JMaximum%exceeded42b11~aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRIIRfNodataavailable_..i-I "[[TableA40.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachI.I'_._-/MainstemflowatGoldCreek(cfs)rNaturala.1200090008000aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIbybreachingeffectscRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPR[r-'I~ r1[[TableA41.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachII.IMainstemflowatGoldCreek(cfs)Natural~1200090008000[l.-J'1[nIL,[[[~.#Groundwater&SurfacewaterRequiredflow(cfs)8888Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow18.011.24.22.0Surfacewaternecessaryforpassage(cfs)aa3.86.0Amountofpptneededforbasinareaof5.03mile2(in)aa.02.03%Exceededbasedontotaldailypptandgroundwater1001002824Breaching%exceededforcontrollingdischargeof12,000cfs71100a aBackwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded100100b2824L[[aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIIbybreachingeffectsdBreachingoccurspriortobackwatereffects[[r--'L I'[[,[[I'r-~L~I'ur~L-JI'~_..Jr~IL,TableA42.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachIII.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)7c777Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow17.510.94.11.9Surfacewaternecessaryforpassage(cfs)002.95.1Amountofpptneededforbasinareaof5.03mile2(in)00.01.02%Exceededbasedontotaldailypptandgroundwater1001003126Breaching%exceededforcontrollingdischargeof12,000cfs7110000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded100100b3126aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIIIbybreachingeffectscRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRdBreachingoccurspriortobackwatereffects I'[TableA43.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachIV.I'MainstemflowatGoldCreek(cfs)Natural~1200090008000~Groundwater&Surfacewater~,Requiredflow(cfs)7777..,Groundwaterbaseflow(cfs)correspundingtospecifiedmainstemflow17.510.94.11.9,Surfacewaternecessaryforpassage(cfs)o o2.95.1~Amountofpptneededforbasinareaof5.03mile2(in)0o.01.02~%Exceededbasedontotaldailypptandgroundwater1001003126r,~..JBreaching%exceededforcontrollingdischargeof12,000ds71100ooC'I-',Backwater%exceededformainstemdischargeofdcfsMaximum%exceededd100d100bd31d26aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIVbybreachingeffectsdBreachingoccurspriortobackwatereffects--'........;~' [[TableA44.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachV.I'MainstemflowatGoldCreek(cfs)Natural~1200090008000I'[Groundwater&SurfacewaterRequiredflow(cfs)18.181818r'~u[[Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow17.4Surfacewaternecessaryforpassage(cfs)0.6Amountofpptneededforbasinareaof.52mile2(in).0310.87.2.324.014..0.631.916.1.73Iw%Exceededbasedontotaldailypptandgroundwater2421.5[I''-'r..........Breaching%exceededforcontrollingdischargeof12,000cfs71Backwater%exceededformainstemdischargeofdcfsdMaximum%exceeded71100d100bod1od.5"~[[aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRVbybreachingeffectsdBreachingoccurspriortobackwatereffects[[[ [[[TableA45.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachVI.[18.11.920.8116.0204.0.7210.7209.3.42MainstemflowatGoldCreek(cfs)20cNatural~1200090008000Surfacewaternecessaryforpassage(cfs)2.8Requiredflow(cfs)Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow17.2Amountofpptneededforbasinareaof.52mile2(in).13Groundwater&Surfacewater[[[[[[%Exceededbasedontotaldailypptandgroundwater71.5o[[[Breaching%exceededforcontrollingdischargeof12,000cfs71Backwater%exceededformainstemdischargeofdcfsdMaximum%exceeded71100d100bod.5odo[[[[[[aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRVIbybreachingeffectscRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRdBreachingoccurspriortobackwatereffects nII'[TableA46.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel-21forPassageReachVII.I'MainstemflowatGoldCreek(cfs)Natural~1200090008000I'Groundwater&SurfacewaterRequiredflow(cfs)20c202020Groundwaterbaseflow(cfs)LJcorrespondingtospecifiedmainstemflow16.8 10.43.91.8Surfacewaternecessaryforpassage(cfs)3;29.616.118.2[Amountofpptneededforbasinareaof.52mile2(in).14.43.73.82n%Exceededbasedontotal'--'dailypptandgroundwater61.50[Breaching%exceededforcontrollingdischargeof12,000cfs7110000nBackwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded71100b.50bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRVIIbybreachingeffectsaNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)L~cRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRI'dBreachingoccurspriortobackwatereffects[1=L>l....-J[r"'L '1TableA47.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachVIII.~,MainstemflowatGoldCreek(cfs)"'Natura181200090008000,Groundwater&SurfacewaterRequiredflow(cfs)20c202020~..,Groundwaterbaseflow(cfs)__Jcorrespondingtospecifiedmainsternflow16.510.23.81.8-,-JSurfacewaternecessaryforpassage(cfs)3.59.816.218.2.-~-JAmountofpptneededforbasinareaof.52mile2(in).16.44.73.82,%Exceededbasedontotaldailypptandgroundwater41.50Breaching%exceededfor_-1controllingdischargeof16,000cfs7110000-,_.JBackwater%exceededforrnainstemdischargeofdcfsddddMaximum%exceeded71100b.50-JaNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)~b-~~~cForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRVIIIbybreachingeffectsRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRdBreachingoccurspriortobackwatereffects-J -,-,-,-1~.-,~,---'-,---'~_J.,.-'-,___3'.-->TableA48.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflow?andbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachIX.MainstemflowatGoldCreek(cfs)Naturala1200090008000Groundwater&SurfacewaterRequiredflow(cfs)20202020Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflow16.410.23.81.8Surfacewaternecessaryforpassage(cfs)3.69.816.2 18.2Amountofpptneededforbasinareaof.52mile2(in).16.44.73 .82%Exceededbasedontotaldailypptandgroundwater41.50Breaching%exceededforcontrollingdischargeof12,000cfs7110000Backwater%exceededformainstemdischargeofdcfsddddMaximum%exceeded71100b.50aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs(ADF&G1984c)bForCaseEV,themainstemdischargeperiodof18000cfswillassistpassagethroughPRIXbybreachingeffectsdBreachingoccurspriortobackwatereffects --,r-,TableA49.Requiredflow,passagereachflowsandpercentexceedanceofsuccessfulpassageduetogroundwaterandsurfacewaterdischarges,breachingflowsandbackwatereffectsfortheperiodof20Augustto20SeptemberatSideChannel21forPassageReachX.MainstemflowatGoldCreek(cfs)Natural~1200090008000Groundwater&Surfacewaterr-,---J--,Requiredflow(cfs)Groundwaterbaseflow(cfs)correspondingtospecifiedmainstemflowSurfacewaternecessaryforpassage(cfs)5c12.5o57.8o52.92.151.43.6Amountofpptneededforbasinareaof.52mile2(in)0a.09.16-.I--,...-:.l%ExceededbasedontotaldailypptandgroundwaterBreaching%exceededforcontrollingdischargeof24,000cfsBackwater%exceededformainstemdischargeofdcfsMaximum%exceeded10012d100100od100b9ad95od5aNaturalflowsidentifiedby50percentexceedancemainstemdischargeof15,000cfs,(ADF&G1984c)bForCaseEV,.themainstemdischargeperiodof18000cfswillnotassistpassagethroughPRXcRequiredflowestimatedassumingthatrequiredflowatupstreamPRissufficientforpassageatdownstreamPRdBreachingoccurspriortobackwatereffects HXrUNaddVJJJ'1jJJ1uJJ',---,J'~J -,........"~,~,APPENDIXBDetailedMitigationCostsChapter3outlinesmitigationproposalsforseveralsloughsandasidechannel.Thisappendixpresentsthecostsforthevariousmitigationmeasurespresented.Costsfortheseproposalsarepreliminaryandarebasedmostlyonpastexperienceindifferentprojects.Amajorcost,andonedifficulttoevaluateconsistsofmobilizingequipment,materialsandmentothesites.ThesecostsarebasedonusingtheAlaskaRailroadtotransportmuchoftheequipmentandmaterials.Detailsregardingloadingandunloadinganddelayswiththerailroadhavenotbeenevaluatedcompletely•SideChannel21andSlough21donothaveaccesstotherailroadorotherlandtransportationduringtheconstructionseason.Threealternativesexisttomobilizeequipmenttothissite._J!1)Helicopter:AdvantagesDisadvantagesareveryequipmentsize.intiming,highcostspeedandandscheduling.severelimitof~I2)Barge:Advantagesinlowercosts,someabilitytoscheduleandoperateefficiently.Disadvantageofshallowdraftinriver,equipmentsizemaybelimited.3)Mobilizingduringwinter:Advantageofequipmentandsuppliesintoworksitebygettinglargetransportover--,,-'-'riverice.Disadvantagesareposedbylongleadtimetomobilizematerials,tyingupequipmentforoneyearbeforedemobilizationcouldbecompleted.CostsinthissectionforSloughandSideChannel21arebasedontheassumptionthatriverconditionsaresuchthatbargesmaybeoperatedtothesite. --,---..,-..,---.,Slough8A1SloughMouthExcavationLaborEquipmentMobilization/DemobilizationEngineering/ManagementTotal1WingDeflectorLabor.Equipment/MaterialsMobilization/DemobilizationEngineering/ManagementTotalExcavationof6PassageReachesLaborEquipment/MaterialsMobilization/DemobilizationEngineering/ManagementTotalBuildupof2SloughBermsLaborEquipmentMobilization/DemobilizationEngineering/ManagementTotal6,0008,0007,0005,0005,0009,0005,0005,0002,0003,0002,0003,000120,00040,0002,0003,000$26,000$24,000$10,000$295,000TOTALCOSTSOFMITIGATIONMEASURESFORSLOUGH8A$355,000 [[l.I'~~I'L-l[[[[[~-J~Slough91RockWeirLaborEquipment/MaterialsMobilization/DemobilizationEngineering/ManagementTotal1BuildupofSloughBermLaborEquipmentMobilization/DemobilizationGravelandCoreProcessingEngineering/ManagementTotal20LogBarriersLaborMaterials/EquipmentMobilization/DemobilizationEngineering/ManagementTotalExcavationof2PassageReachesLaborMaterials/EquipmentMobilization/DemobilizationEngineering/ManagementTotal1SloughMouthExcavationLaborEquipmentMobilization/DemobilizationEngineering/ManagementTotal9,00014,0008,0006,000$37,00060,00020,00010,00040,00020,000$150,00020,0002,0002,0006,000$30,0002,0001,0002,0002,000$7,0006,0008,0007,0005,000$26,000I'LL[[TOTALCOSTSOFMITIGATIONMEASURESFORSLOUGH9$250,000 -,~-.,-.-.-.-.J-.-.J~-.Slough9A1BuildupofSloughBermLaborEquipmentMobiliz~tion/DemobilizationGravelandCoreProcessingEngineering/ManagementTotalExcavationofEntireSloughLaborEquipment/MaterialsMobilization/DemobilizationGravelProcessingEngineering/ManagementTotal60,00020,00010,00040,00020,0006,0007,0005,00055,0003,000$150,000$76,000---'---'-'.--,---'-J..J-JTOTALCOSTSOFMITIGATIONMEASURESFORSLOUGH9A$226,000 !-.Slough11~2WeirsLabor18,000Equipment/Materials28,000Mobilization/Demobilization8,000Engineering/Management7,000Total$61,000BankStabilization1000ftLabor8,000Materials/Equipment7,000,Mobilization/Demobilization5,000Engineering/Management5,000--'Total$25,000-,SloughExcavationLabor6,000Equipment/Materials7,000Mobilization/Demobilization5,000--'GravelProcessing5,000Engineering/Management3,000Total$26,000--'15LogBarriersLabor15,000Materials/Equipment2,000--'Mobilization/Demobilization2,000Engineering/Management5,000Total$24,000_41BuildupofProtectiveBermLabor60,000Equipment20,000-",Mobilization/Demobilization10,000GravelandCoreProcessing40,000Engineering/Management20,000Total$150,000-,--'TOTALCOSTSOFMITIGATIONFORSLOUGH11$286,000--,--' TOTALCOSTSOFMITIGATIONFORSIDECHANNEL11[r1l_~[I'L~....l_[[[[[[[[tl[[r'UpperSideChannel11ExcavationofChannelLaborEquipment/MaterialsMobilization/DemobilizationGravelProcessingEngineering/ManagementTotalBuildupofProtectiveBermLaborEquipmentMobilization/DemobilizationGravelandCoreProcessingEngineering/ManagementTotal6,0007,0005,0005,0003,00060,00020,00010,00040,00020,000$26,000$150,000$176,000 ,TOTALCOSTSOFMITIGATIONMEASURESFORSIDECHANNEL21~-,l_--,"I'I~,I~".-...,[["iL-JrL-J,.-JJJSideChannel21ExcavationofChannelLaborEquipment/MaterialsMobilization/DemobilizationGravelProcessingEngineering/ManagementTotal7WingDeflectorsBankStabilizationLaborMaterials/EquipmentMobilization/DemobilizationOversizeMaterialRemovalEngineering/ManagementTotal8,0009,00011,0008,0009,00070,00065,00020,00035,00050,000$45,000$240,000$285,000 -1-,-"-,-',Slough21ExcavationtoLowerSloughProfileLaborEquipment/MaterialsMobilization/DemobilizationOversizeSubstrateRemovalEngineering/ManagementTotalWaterSupplySystemLaborMaterials/EquipmentPipingMobilization/DemobilizationEngineering/ManagementTotal5,0006,0005,00010,0008,00055,00030,0009,00020,00020,000$34,000$134,000-'-,-,..JTOTALCOSTSOFMITIGATIONMEASURESFORSLOUGH21$168,000 ~~[i'r~r-""'I--'[[I'L..JI~LJI'IW>=JLJ;~"'-'-'-......}CurrySloughDevelopmentPropagationSystemLaborEquipment/MaterialsPipeGravelProcessingMobilization/DemobilizationEngineering/ManagementTotalCurryStationDevelopmentPropagationSystemLaborEquipmentMaterialsGravelProcessingMobilizationDemobilizationEngineering/ManagementTotal135,00080,000100,00030',00035,00070,00015,00035,0008,00010,00013,000$450,000$81,000 .'INTERIMMITIGATIONPLANFORARCTICGRAYLINGHABITATINTHEIMPOUNDMENTAREA 1 -INTRODUCTIONANDBACKGROUNDTheprimarylong-termimpactassociatedwiththefillingoftheWatanaandDevilCanyonreservoirsisthelossofclear-watertributaryhabitat(AcresAmerican1983)•Thetributaryhabitatthatwillbeiinundatedc~rrentlysupportsasubstantialpopulationofArcticgrayling,estimatedtobeatleast16,300fishin1982.Aquatichabitatswithinthereservoirsarenotexpectedtosupportasigni-ficantgraylingpopulation.Intheimpoundmentarea,Arcticgraylingwasselectedastheevaluationspeciesformitigationbecauseofitsabundanceinthearea,itssensitivitytoimpactsduringallseasonsandlifestages,anditsdesirabilityasasportfish.Measurestoavoid,minimize,rectifyorreducetheanticipatedlossofspawningandArcticgraylinghabitatsareconsideredinfeasible(AcresAmerican1983).Therefore,measurestocompensateforthelossofArcticgraylinghabitataretheoptionsbeingconsideredforimpoundmentmitigationplanning.ImpoundmentmitigationoptionstocompensateforlostArcticgraylinghabitatwereoutlinedinExhibitE,FederalEnergyRegulatoryCommissionLicenseApplication(AcresAmerican1983)andincluded:(1)fundingofresearchonArcticgraylingpropagationtechnology;(2)hatcherypropagationofArcticgraylingandthesubsequentstockingoftherearedfish(i.e.fingerling);(3)stockingofhatchery-rearedrainbowtroutifArcticgraylingpropagationprovedtobetechnicallyinfeasible;and(4)theintroductionofrainbowtroutintotheDeviiCanyonreservoir.Agencycommentsonthehatchery-rearingofArcticgraylingweregenerallynegativeandconcludedthatgraylingproductioninAlaskamustbeconsideredIexperimentalandcompensationmustbejudgedasspeculative(ADF&G1983c).Reasonsfor·thispositionwere:(1)thelackofareliableeggsource;(2)lowsurvivalfromthegreeneggtofrystage;(3)unsuccessfulattemptstoreargraylingfrytofingerlinginhatcheries;and(4)theinabilitytoevaluatesurvival·ofstockedfrybecauseoftheirsmallsize. 2 -MitigationOptions2.1-RainbowTroutRainbowtroutisthespeciesbeingconsideredforprimarycompensationforlostArcticgraylinghabitat.ArainbowtroutpropagationandastockingprogramhasdocumentedsuccessinAlaskaandthereisahighdemandforthespeciesbysportanglers.ItappearsthatDevilCanyonreservoirmaybetooturbidtosuccessfullygrowrainbowtrouttoadesiredsize.TurbiditylevelsinDevilCanyonreservoirareexpectedtobeintherangeof40-50NTUswithlightpenetratingaboutonemeterintothewatercolumn(TomStewart,Harza-Ebasco,pers.comm.1984).PrimaryproductioninDevilCanyonreservoirisexpectedtobelowasaresultoftheturbiditylevels.BecausethesuccessofastockingprogramofrainbowtroutinDevilCanyonreservoirisuncertain,itmaybedesirabletomonitorthereservoirlimnologyandresidentfishpopulationsthatwilloccurnaturallybeforeinitiatingastockingprogramforanyspecies.Sportfishingopportunitieswouldbeavailabletoalargernumberofpeopleiffishwerestockednearpopulationcenters.Additionally,stockingsitescanbechosenthatwillhaveahigherprobabilityofsuccessthanDevilCanyonreservoir.RainbowtrouthavebeensuccessfullystockedinnumerouslakesintheMatanuska-SusitnaValleyarea(LarryEngel,ADF&G,Palmer,pers.comm.1984).Casehistories,costanalysesandstockingareasforarainbowtroutstockingprogramwillbediscussedintheimpoundmentmitigationplanscheduledfor1985.2.2-ArcticGraylingArcticgraylingstockingisdesirablebecauseof"in-kind"replacementforlostspawningandrearinghabitat.In1984,significantprogresswasmadeinArcticgraylingpropagationtechnology.About100,000 graylingfingerling(approximately50to60mm)wererearedatClearHatchery(D.Parks,ADF&GHatcheryManager,Clear,Alaska,pers.co~.1984).Feedingexperimentswithvariouskindsofcommercialfeeds,automaticfeeders,andincreasedlightintensityarefactorsthatwerethoughttobeimportantinthesuccessfulrearingofgraylingfingerling.Thesurvivalratewasabout70percentfromemergentsac-fryto2gramfingerlingforoneexperimentalgroup,whichisaboutseventimesgreaterthanprevioussurvivalratesforemergentsac-frytofingerling.BecausesignificantprogressinArcticgraylingpropagationtechnologyisbeingmadeandthedesirabilityof"in-kind"replacement,graylingisstillconsideredaprimarycandidatespeciesforcompensation.TheimpoundmentmitigationplanscheduledforApril1985willdis<;:usspropagationtechnologyforArcticgraylingandexamineareasthatneedfurtherresearch,suchasbroodstockdevelopment,commercialfeeds,vitamindeficiencies,diseaseproblems,stockingevaluation,stockingareas•.,., 3 -REFERENCESAcresAmericanIncorporated.1983.Applicationforlicenseformajorproject,Susitna~ydroelectricProject,beforetheFederalEnergyRegulatoryCommission.Vol.6A.ExhibitE,Chaps.3.AlaskaPowerAuthority.SusitnaHydroelectricProject.ADF&G1983c.ReviewComments-DraftExhibitE -SusitnaHydroelectricProject.PreparedforAlaskaPowerAuthority.Engel,L.1984.PersonalCommunication.ADF&GPalmer,Alaska.Parks,D.1984.PersonalCommunication.ADF&GClear,Alaska.Stewart,T.1984.PersonalCommunication.Harza-Ebasco.Anchorage,Alaska: