Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
APA1656
FERC/DEIS-0038TKFEDERALENERGYREGULATORYCOMMISSIONOFFICEOFELECTRICPOWERREGULATIONDRAFTENVIRONMENTALIMPACTSTATEMENTSUSITNAHYDROELECTRICPROJECTFERCNO.7114-ALASKAVolume4.AppendixH.WaterResourcesAppendixI.FisheriesandAquaticResourcesApplicant:AlaskaPowerAuthority333West4thAvenueSuite31Anchorage,Alaska99501AdditionalcopiesoftheDraft-EISmaybeorderedfrom:DivisionofPublicInformationFederalEnergyRegulatoryCommission825NorthCapitolSt.,NE.Washington,D.C.20426May1984Lfur~Anchorage,AJaskaFERC/DEIS-0038TKFEDERALENERGYREGULATORYCOMMISSIONOFFICEOFELECTRICPOWERREGULATIONDRAFTENVIRONMENTALIMPACTSTATEMENTSUSITNAHYDROELECTRICPROJECTFERCNO.7114-ALASKAVolume4.AppendixH.WaterResourcesAppendixI.FisheriesandAquaticResourcesApplicant:AlaskaPowerAuthority333West4thAvenueSuite31Anchorage,Alaska99501AdditionalcopiesoftheDraft-EISmaybeorderedfrom:DivisionofPublicInformationFederalEnergyRegulatoryCommission825NorthCapitolSt.,NE.Washington,D.C.20426May1984Lfur~Anchorage,AJaska ivLISTOFFIGURESFigureCOVERPHOTO:Artist'sRenditionoftheProposedWatanaDamandReservoirI-56APPENDIXH.WATERRESOURCESH.l-lSusitnaRiverBasin. . . . . . . . . . . . . . . . . . . . . . . . . .H-4H.I-2LongitudinalProfileoftheMainstemoftheSusitnaRiver. . . .H-5H.I-3GeneralHabitatTypesintheMiddleSusitnaRiverBasin. . . . . . . .H-8H.I-4Side-ChannelSloughsStudiedintheADFGSuHydroAquaticStudiesProgramH-13H.I-5MorphologyofaTypicalSide-ChannelSlough. . . . . .......H-14H.2-1RepresentativeAnnualHydrographsattheWatanaDamSiteandtheGoldCreekGagingStationforTwoWetYearswithSpring(1954)andFall(1967)FloodsandforOneDryYear(1970). . . . . . . . . . . . . . . . . . . . . . .H-20H.2-2RecurrenceIntervalsfor7-DayHighFlowsatGoldCreekDuringOpen-WaterMonths(May-August)andAIce-Covered,Low-FlowMonth(March). . . . .H-22H.2-3Pre-ProjectFlowDurationCurvesfortheGoldCreekandSunshineGagingStationsBasedonMeanDailyFlows.. . . . . . . . . . . . . . . . . . .H-24H.2-4RecurrenceIntervalsfor7-DayLowFlowsatGoldCreekDuringOpen-WaterMonths(May-August)andAIce-Covered,Low-FlowMonth(March). . . . . .H-25H.2-5FlowDurationCurvesatGoldCreekforPre-Project,Watana,andWatana-DevilCanyonOperationalFlows.. . . . . . . . . . . . . . . . . . . . . . . . .H-31H.2-6FlowDurationCurvesatSunshineforPre-Project,Watana,andWatana-DevilCanyonOperationalFlows.. . . . . . . . . . . . . . . . . . . . . . . . .H-32H.2-7ComparisonofRecurrenceIntervalsforMeanAnnualFloodsatGoldCreekUnderPreproject,Watana,andWatana-DevilCanyonOperationalFlowRegimes.H-33H.3-1CumulativeResponseofSloughAccessibilitytoMainstemDischarge. . . . .H-39H.3-2ResponseofZoneH-IIWettedSurfaceAreatoMainstemFlows. . . . . . . .H-42H.3-3ChangesinTotalWettedSurfaceAreainSloughsDuringFilling,Watana,andWatana-DevilCanyonOperationalFlows. . . . . . . . . . . . . .H-43H.5-1LocationsofSamplingStationsforSalinityinCookInlet. . . .H-46H.5-2SeasonalPatternintheSalinityofWaterinCookInletatNodes1,12,and27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H-47APPENDIXI.FISHERIESANDAQUATICRESOURCES1.1-1AquaticInvertebratesUsedforFoodbyJuvenileSalmonfromRepresentativeRearingHabitatsinSusitnaRiverSloughsandTributaries. . . . . . .1-51.1-2GeneralTimingofLife-CycleActivitiesofPacificSalmonintheSusitnaRiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-71.1-3ChinookSalmon-GeneralizedLifeCycleandHabitatSuitabilityintheSusitnaRiverDrainage. . . . . . . . . . . . . . . . . . . . . . . . .1-81.1-4UpperCookInletandtheSusitnaDrainageShowingPercentageofSalmonMigratingPastSunshineStationandtheRelativeSizesofRunsPasttheYentnaandSunshineStations.. . . . . . . . . . . . . . . . . . . .1-91.1-5SockeyeSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.1-121.1-6CohoSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.. .1-141.1-7ChumSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.. .1-161.1-8PinkSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.. .1-181.1-9Eulachon-GeneralizedLifeCycleandHabitatSuitabilityintheSusitnaRiverDrainage.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-191.1-10BeringCisco-GeneralizedLifeCycleintheSusitnaRiverDrainage1-211.1-11SusitnaRiverandMajorTributariesfromMouthtoLittleWillowCreek.1-361.1-12SusitnaRiverandMajorTributariesfromMontanaCreektoDevilCanyon.1-371.1-13SusitnaRiverandMajorTributariesfromDevilCanyontoDenaliHighway. .1-381.2-1PredictedEarlyEmergenceofPinkandChumSalmonSpawnedonJuly15atFourLocationsintheSusitnaRiverBetweenDevilCanyonOutletandtheChulitnaJunction.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I-521.2-2 IncubationRa.t€!sJrfpr.~humSalmonSpawnedonAugust15UnderDifferentTemperatureJ$cenar·l0s"J.. . . . . . . . . . . . . . . . . . . . . . .I-54GrowthforRepresentativeJuvenileSalmonin1CanyonandTalkeetna,BeforeandAfterivLISTOFFIGURESFigureCOVERPHOTO:Artist'sRenditionoftheProposedWatanaDamandReservoirI-56APPENDIXH.WATERRESOURCESH.l-lSusitnaRiverBasin. . . . . . . . . . . . . . . . . . . . . . . . . .H-4H.I-2LongitudinalProfileoftheMainstemoftheSusitnaRiver. . . .H-5H.I-3GeneralHabitatTypesintheMiddleSusitnaRiverBasin. . . . . . . .H-8H.I-4Side-ChannelSloughsStudiedintheADFGSuHydroAquaticStudiesProgramH-13H.I-5MorphologyofaTypicalSide-ChannelSlough. . . . . .......H-14H.2-1RepresentativeAnnualHydrographsattheWatanaDamSiteandtheGoldCreekGagingStationforTwoWetYearswithSpring(1954)andFall(1967)FloodsandforOneDryYear(1970). . . . . . . . . . . . . . . . . . . . . . .H-20H.2-2RecurrenceIntervalsfor7-DayHighFlowsatGoldCreekDuringOpen-WaterMonths(May-August)andAIce-Covered,Low-FlowMonth(March). . . . .H-22H.2-3Pre-ProjectFlowDurationCurvesfortheGoldCreekandSunshineGagingStationsBasedonMeanDailyFlows.. . . . . . . . . . . . . . . . . . .H-24H.2-4RecurrenceIntervalsfor7-DayLowFlowsatGoldCreekDuringOpen-WaterMonths(May-August)andAIce-Covered,Low-FlowMonth(March). . . . . .H-25H.2-5FlowDurationCurvesatGoldCreekforPre-Project,Watana,andWatana-DevilCanyonOperationalFlows.. . . . . . . . . . . . . . . . . . . . . . . . .H-31H.2-6FlowDurationCurvesatSunshineforPre-Project,Watana,andWatana-DevilCanyonOperationalFlows.. . . . . . . . . . . . . . . . . . . . . . . . .H-32H.2-7ComparisonofRecurrenceIntervalsforMeanAnnualFloodsatGoldCreekUnderPreproject,Watana,andWatana-DevilCanyonOperationalFlowRegimes.H-33H.3-1CumulativeResponseofSloughAccessibilitytoMainstemDischarge. . . . .H-39H.3-2ResponseofZoneH-IIWettedSurfaceAreatoMainstemFlows. . . . . . . .H-42H.3-3ChangesinTotalWettedSurfaceAreainSloughsDuringFilling,Watana,andWatana-DevilCanyonOperationalFlows. . . . . . . . . . . . . .H-43H.5-1LocationsofSamplingStationsforSalinityinCookInlet. . . .H-46H.5-2SeasonalPatternintheSalinityofWaterinCookInletatNodes1,12,and27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H-47APPENDIXI.FISHERIESANDAQUATICRESOURCES1.1-1AquaticInvertebratesUsedforFoodbyJuvenileSalmonfromRepresentativeRearingHabitatsinSusitnaRiverSloughsandTributaries. . . . . . .1-51.1-2GeneralTimingofLife-CycleActivitiesofPacificSalmonintheSusitnaRiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-71.1-3ChinookSalmon-GeneralizedLifeCycleandHabitatSuitabilityintheSusitnaRiverDrainage. . . . . . . . . . . . . . . . . . . . . . . . .1-81.1-4UpperCookInletandtheSusitnaDrainageShowingPercentageofSalmonMigratingPastSunshineStationandtheRelativeSizesofRunsPasttheYentnaandSunshineStations.. . . . . . . . . . . . . . . . . . . .1-91.1-5SockeyeSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.1-121.1-6CohoSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.. .1-141.1-7ChumSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.. .1-161.1-8PinkSalmon-GeneralizedLifeCycleintheSusitnaRiverDrainage.. .1-181.1-9Eulachon-GeneralizedLifeCycleandHabitatSuitabilityintheSusitnaRiverDrainage.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-191.1-10BeringCisco-GeneralizedLifeCycleintheSusitnaRiverDrainage1-211.1-11SusitnaRiverandMajorTributariesfromMouthtoLittleWillowCreek.1-361.1-12SusitnaRiverandMajorTributariesfromMontanaCreektoDevilCanyon.1-371.1-13SusitnaRiverandMajorTributariesfromDevilCanyontoDenaliHighway. .1-381.2-1PredictedEarlyEmergenceofPinkandChumSalmonSpawnedonJuly15atFourLocationsintheSusitnaRiverBetweenDevilCanyonOutletandtheChulitnaJunction.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I-521.2-2 IncubationRa.t€!sJrfpr.~humSalmonSpawnedonAugust15UnderDifferentTemperatureJ$cenar·l0s"J.. . . . . . . . . . . . . . . . . . . . . . .I-54GrowthforRepresentativeJuvenileSalmonin1CanyonandTalkeetna,BeforeandAfter vLISTOFTABLESTableAPPENDIXH.WATERRESOURCESH.1-1MainChannelWaterSurfaceElevationsfromDeadmanCreektoDevilCreekPredictedbyHEC-2Modeling.H.1-2MainChannelWaterSurfaceElevationsfromDevilCanyontoTalkeetnaPredictedbyHEC-2Modeling.H.2-1USGSGagingStationsfortheSusitnaRiverBasin.H.2-2Maximum,Mean,andMinimumMonthlyFlowsintheSimulated,32-YearDataSetfortheSusitnaRiverBasin.H.2-3HistoricalMonthlyFlowsatGoldCreekIncludingAdjustedDataforWY.H.2-4HistoricalMonthlyFlowsEstimatedattheSunshineUSGSGagingStation.H.2-5MaximumFlowsofRecordatSelectedUSGSGagingStationsintheSusitnaRiverBasin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H-23H.2-6PredictedPostprojectMonthlyFlowsatGoldCreekUnderWatanaOperationH-27H.2-7PredictedPostprojectMonthlyFlowsatSunshineUnderWatanaOperation.H-28H.2-8PredictedPostprojectMonthlyFlowsatGoldCreekUnderCombinedWatana-DevilCanyonOperation.. . . . . . . . . . . . . . . . . . . . . . . . . . . . .H-29H.2-9PredictedPostprojectMonthlyFlowsatSunshineUnderCombinedWatana-DevilCanyonOperation.. . . . . . . . . . . . . . . . . . . . . . . . . . .H-30H.3-1ThresholdsinMainstemFlowatWhichHydraulicRegimesOccuratSelectedSide-ChannelSloughs. . . . . . . . . . . . . . . . . . . . . . . . . .H-34H.3-2FrequencyofOccurrenceofVariousHydraulicRegimesofSideSloughsinOpenwaterSeasonBeforeandAfterProjectBeginsOperations. . . . . .H-35H.3-3CalculationofIce-RelatedStagingRequiredforWinterOvertoppingofSe1ectedSloughs. . . . . . . . . . . . . . . . . . . . . . . . . . . .H-36H.3-4AccessThresholdsofMainstemDischargeatGoldCreekforSelectedSide-ChannelSloughsBetweenDevilCanyonandTalkeetna,IncludingRelativeUtilizationbyAdultSalmonin1981and1982. . . . . . . . . . .H-38H.3-5Frequencyof,AccessLimitationsinSelectedSloughsH-38H.3-6WettedSurfaceAreasinSloughsAboveTalkeetnaH-40H.3-7WettedSurfaceAreasinSloughsBelowTalkeetna. .H-41APPENDIXI.FISHERIESANDAQUATICRESOURCES1.1-1InvertebrateTaxaPresentinDriftNetandKickScreenCollectionsfromAllSitesSampledin1982. . . . . . . . . . . . . . . . . . . . . . . . . . .1-41.1-2CommonandScientificNamesofFishSpeciesRecordedfromtheSusitnaBasin1-61.1-3DailyTemperatureUnitRequiredforEggDevelopmentofPacificSalmon. . .1-101.1-4ArcticGraylingPopulationEstimatesbyTributaryHabitatEvaluationLocation,ProposedImpoundmentAreas,1982. . . . . . . . . . . . . . . . . . . . . .1-231.1-5Side-ScanSonarCountsofSalmonMigratingPastYentnaStationandPetersonPopulationEstimatesandCorresponding95%ConfidenceIntervalsofSalmonMigratingtoSunshine,TalkeetnaandCurryStations,1981-1982. . . . . . .1-281.1-6EstimatedNumberofSlough-SpawningSockeye,Chum,andPinkSalmoninSloughsBetweenDevilCanyonandTalkeetna,1981to1982. . . . . . . . . . . . .1-301.1-7CommercialCatchofUpperCookInletSalmoninNumbersofFishbySpecies,1954-1982. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-341.1-8SusitnaBasinSportFishHarvestandEffortbyFisheryandSpecies-1978,1979,1980and1981. . . . . . . . . . . . . . . . . . . . . . . . . . .1-391.1-9GoalsoftheCookInletRegionalSalmonEnhancementPlanforEven-YearandOdd-YearRuns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-431.2-1ChangeinPotentialSummerGrowthofJuvenileSalmonintheTalkeetnatoMouthReachDuetoFillingofWatanaReservoirandOperationofWatanaandDevilCanyonDams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-471.2-2DatesEstimatedforEmergenceofSalmonFrythatExperienceJuly-AprilTemperaturesProjectedfortheSusitnaRiveratSeveralLocationsBetweenDevilCanyonandtheChulitnaRiverConfluence.. . . . . . . . . . . . .I-531.2-3AnalysistoTesttheHypothesisforEachofFiveSalmonSpeciesthatThereisaTendencyforYear-ClassStrengthtobeBelowAverageforThoseYearClassesExperiencingLowerthanAverageFlowsDuringtheSpawningPeriodJulythroughSeptember. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-65vLISTOFTABLESTableAPPENDIXH.WATERRESOURCESH.1-1MainChannelWaterSurfaceElevationsfromDeadmanCreektoDevilCreekPredictedbyHEC-2Modeling.H.1-2MainChannelWaterSurfaceElevationsfromDevilCanyontoTalkeetnaPredictedbyHEC-2Modeling.H.2-1USGSGagingStationsfortheSusitnaRiverBasin.H.2-2Maximum,Mean,andMinimumMonthlyFlowsintheSimulated,32-YearDataSetfortheSusitnaRiverBasin.H.2-3HistoricalMonthlyFlowsatGoldCreekIncludingAdjustedDataforWY.H.2-4HistoricalMonthlyFlowsEstimatedattheSunshineUSGSGagingStation.H.2-5MaximumFlowsofRecordatSelectedUSGSGagingStationsintheSusitnaRiverBasin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H-23H.2-6PredictedPostprojectMonthlyFlowsatGoldCreekUnderWatanaOperationH-27H.2-7PredictedPostprojectMonthlyFlowsatSunshineUnderWatanaOperation.H-28H.2-8PredictedPostprojectMonthlyFlowsatGoldCreekUnderCombinedWatana-DevilCanyonOperation.. . . . . . . . . . . . . . . . . . . . . . . . . . . . .H-29H.2-9PredictedPostprojectMonthlyFlowsatSunshineUnderCombinedWatana-DevilCanyonOperation.. . . . . . . . . . . . . . . . . . . . . . . . . . .H-30H.3-1ThresholdsinMainstemFlowatWhichHydraulicRegimesOccuratSelectedSide-ChannelSloughs. . . . . . . . . . . . . . . . . . . . . . . . . .H-34H.3-2FrequencyofOccurrenceofVariousHydraulicRegimesofSideSloughsinOpenwaterSeasonBeforeandAfterProjectBeginsOperations. . . . . .H-35H.3-3CalculationofIce-RelatedStagingRequiredforWinterOvertoppingofSe1ectedSloughs. . . . . . . . . . . . . . . . . . . . . . . . . . . .H-36H.3-4AccessThresholdsofMainstemDischargeatGoldCreekforSelectedSide-ChannelSloughsBetweenDevilCanyonandTalkeetna,IncludingRelativeUtilizationbyAdultSalmonin1981and1982. . . . . . . . . . .H-38H.3-5Frequencyof,AccessLimitationsinSelectedSloughsH-38H.3-6WettedSurfaceAreasinSloughsAboveTalkeetnaH-40H.3-7WettedSurfaceAreasinSloughsBelowTalkeetna. .H-41APPENDIXI.FISHERIESANDAQUATICRESOURCES1.1-1InvertebrateTaxaPresentinDriftNetandKickScreenCollectionsfromAllSitesSampledin1982. . . . . . . . . . . . . . . . . . . . . . . . . . .1-41.1-2CommonandScientificNamesofFishSpeciesRecordedfromtheSusitnaBasin1-61.1-3DailyTemperatureUnitRequiredforEggDevelopmentofPacificSalmon. . .1-101.1-4ArcticGraylingPopulationEstimatesbyTributaryHabitatEvaluationLocation,ProposedImpoundmentAreas,1982. . . . . . . . . . . . . . . . . . . . . .1-231.1-5Side-ScanSonarCountsofSalmonMigratingPastYentnaStationandPetersonPopulationEstimatesandCorresponding95%ConfidenceIntervalsofSalmonMigratingtoSunshine,TalkeetnaandCurryStations,1981-1982. . . . . . .1-281.1-6EstimatedNumberofSlough-SpawningSockeye,Chum,andPinkSalmoninSloughsBetweenDevilCanyonandTalkeetna,1981to1982. . . . . . . . . . . . .1-301.1-7CommercialCatchofUpperCookInletSalmoninNumbersofFishbySpecies,1954-1982. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-341.1-8SusitnaBasinSportFishHarvestandEffortbyFisheryandSpecies-1978,1979,1980and1981. . . . . . . . . . . . . . . . . . . . . . . . . . .1-391.1-9GoalsoftheCookInletRegionalSalmonEnhancementPlanforEven-YearandOdd-YearRuns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-431.2-1ChangeinPotentialSummerGrowthofJuvenileSalmonintheTalkeetnatoMouthReachDuetoFillingofWatanaReservoirandOperationofWatanaandDevilCanyonDams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-471.2-2DatesEstimatedforEmergenceofSalmonFrythatExperienceJuly-AprilTemperaturesProjectedfortheSusitnaRiveratSeveralLocationsBetweenDevilCanyonandtheChulitnaRiverConfluence.. . . . . . . . . . . . .I-531.2-3AnalysistoTesttheHypothesisforEachofFiveSalmonSpeciesthatThereisaTendencyforYear-ClassStrengthtobeBelowAverageforThoseYearClassesExperiencingLowerthanAverageFlowsDuringtheSpawningPeriodJulythroughSeptember. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-65 DRAFTENVIRONMENTALIMPACTSTATEMENTSUSITNAHYDROELECTRICPROJECT,FERCNO.7114APPENDIXHWATERRESOURCESPreparedbyJerryW.Elwood,DonaldW.Lee,MichaelJ.Sale,andAlanJ.WittenOakRidgeNationalLaboratoryH-1DRAFTENVIRONMENTALIMPACTSTATEMENTSUSITNAHYDROELECTRICPROJECT,FERCNO.7114APPENDIXHWATERRESOURCESPreparedbyJerryW.Elwood,DonaldW.Lee,MichaelJ.Sale,andAlanJ.WittenOakRidgeNationalLaboratoryH-1 APPENDIXH.WATERRESOURCESH.lBASINCHARACTERISTICSH.l.lRiverMorphologyTheheadwatersoftheSusitnaRiveranditsmajor,upperbasintributariesaredominatedbybroad,braided,gravelfloodplainsbelowglaciersintheAlaskaRange(Gattoetal.1980).TheWestForkoftheSusitnaRiverjoinsthemainriverabout18mi(29km)belowSusitnaGlacier.BelowtheWestForkconfluence,theSusitnaRiverdevelopsasplit-channelconfigurationwithnumerousislands.Theriverisgenerallyconstrainedbylowbluffsforabout55mi(89km).ThetwomajortributariesintheupperbasinaretheMaclarenRiver,aglacialtributary,andthenonglacialTyoneRiver,whichdrainsLakeLouiseandtheswampylowlandsofthesoutheasternupperbasin;bothtributariesentertheSusitnaRiverfromtheeast(FigureH.l-l).BelowtheconfluencewiththeTyoneRiver,theSusitnaRiverflowswestfor96mi(154km)throughsteep-walledcanyons.ThisreachcontainstheWatanaandDevilCanyondamsitesatRiverMiles(RMs)184.4and151.6,respectively.Rivergradientsarehigh,averagingnearly14ft/mi(4m/km)inthereachupstreamoftheWatanadamsite.Downstreamfrom.WatanatoDevilCreek,therivergradientisapproximately10.4ft/mi(3.2m/km)(FigureH.1-2).Inthel2-mi(19-km)reachbetweenDevilCreekandDevilCanyon,therivergradientaverages31ft/mi(9.5m/km).ThechanneltypebetweentheTyoneRiverandDevilCanyonisprimarilyasinglechannelwithintermittentislands.CrosssectionsinstudiesbyR&MConsultants,Inc.(1982a),illustratethesingle-channelconfiguration.Bedmaterialconsistsmainlyoflargegravelcobbles.DevilCanyontoTalkeetnaBetweenDevilCanyonandTalkeetna,theSusitnahasbeensubdividedintofiveseparatereaches(R&M1982b).Cross-sectionaldataarecontainedinthereportonhydraulicandicestudiesbyR&MConsultants(1982a).AerialphotographsoftheriverarepresentedinExhibitE,Chapter2.FromRM149toRM144,theSusitnaflowspredominantlyinasinglechannelconfinedbyvalleywalls.Atlocationswherethevalleybottomwidens,depositionofgravelandcobblehasformedmid-channelorside-channelbars.Occasionally,avegetatedislandorfragmentaryfloodplainhasformed,withelevationsabovenormalfloodlevels.Thepresenceofcobblesandbouldersinthebedmaterialaidsinstabilizationofthechannelgeometry.FromRM144toRM139,abroadeningofthevalleybottomhasallowedtherivertodevelopasplitchannelwithintermittent,well-vegetatedislands.Thebankful.lstageisapproximatelyequaltothewatersurfaceelevationatthemeanannualflood.Wherethemainchannelimpingesonvalleywallsorterraces,acobblearmorlayerhasdeveloped,withatopelevationatroughlybankfullfloodstage.AtRM144,aperiglacialalluvialfanofcoarsesedimentsconfinestherivertoasinglechannel.FromRM139toRM129.5,theriverischaracterizedbyawell-definedsplit-channelconfiguration.Vegetatedislandsseparatethemainchannelfromsidechannels.Sidechannelsandsloughsoccurfrequentlyinthealluvialfloodplainandareinundatedonlyatflowsabove15,000to20,000ft3/s(425to566m3/s).Wherethemainchannelimpingesvalleyswallsorterraces,acobblearmorlayerhasdeveloped,withatopelevationatroughlybankfullfloodstage.Themainchannelbedhasbeenfrequentlyobservedtobewellarmored.PrimarytributariesinthisreachincludeIndianRiver(RM138.5),GoldCreek(RM136.8),andFourthofJulyCreek(RM131.1).Eachhasformedanalluvialfanextendingintothevalleybottom,constrictingtheSusitnatoasinglechannel.Eachconstrictionhasestablishedahydrauliccontrolpointthatregulateswatersurfaceprofilesandassociatedhydraulicparametersatvaryingdischarges.FromRM129.5toRM119,riverpatternsaresimilartothoseinthepreviousreach.ProminentcharacteristicsbetweenShermanandCurryincludethemainchannelflowingagainstthewestvalleywallandnumeroussidechannelsandsloughsalongtheeastfloodplain.ThealluvialfanatCurryconstrictstheSusitnatoasinglechannelandterminatestheabovepatterns.H-3APPENDIXH.WATERRESOURCESH.lBASINCHARACTERISTICSH.l.lRiverMorphologyTheheadwatersoftheSusitnaRiveranditsmajor,upperbasintributariesaredominatedbybroad,braided,gravelfloodplainsbelowglaciersintheAlaskaRange(Gattoetal.1980).TheWestForkoftheSusitnaRiverjoinsthemainriverabout18mi(29km)belowSusitnaGlacier.BelowtheWestForkconfluence,theSusitnaRiverdevelopsasplit-channelconfigurationwithnumerousislands.Theriverisgenerallyconstrainedbylowbluffsforabout55mi(89km).ThetwomajortributariesintheupperbasinaretheMaclarenRiver,aglacialtributary,andthenonglacialTyoneRiver,whichdrainsLakeLouiseandtheswampylowlandsofthesoutheasternupperbasin;bothtributariesentertheSusitnaRiverfromtheeast(FigureH.l-l).BelowtheconfluencewiththeTyoneRiver,theSusitnaRiverflowswestfor96mi(154km)throughsteep-walledcanyons.ThisreachcontainstheWatanaandDevilCanyondamsitesatRiverMiles(RMs)184.4and151.6,respectively.Rivergradientsarehigh,averagingnearly14ft/mi(4m/km)inthereachupstreamoftheWatanadamsite.Downstreamfrom.WatanatoDevilCreek,therivergradientisapproximately10.4ft/mi(3.2m/km)(FigureH.1-2).Inthel2-mi(19-km)reachbetweenDevilCreekandDevilCanyon,therivergradientaverages31ft/mi(9.5m/km).ThechanneltypebetweentheTyoneRiverandDevilCanyonisprimarilyasinglechannelwithintermittentislands.CrosssectionsinstudiesbyR&MConsultants,Inc.(1982a),illustratethesingle-channelconfiguration.Bedmaterialconsistsmainlyoflargegravelcobbles.DevilCanyontoTalkeetnaBetweenDevilCanyonandTalkeetna,theSusitnahasbeensubdividedintofiveseparatereaches(R&M1982b).Cross-sectionaldataarecontainedinthereportonhydraulicandicestudiesbyR&MConsultants(1982a).AerialphotographsoftheriverarepresentedinExhibitE,Chapter2.FromRM149toRM144,theSusitnaflowspredominantlyinasinglechannelconfinedbyvalleywalls.Atlocationswherethevalleybottomwidens,depositionofgravelandcobblehasformedmid-channelorside-channelbars.Occasionally,avegetatedislandorfragmentaryfloodplainhasformed,withelevationsabovenormalfloodlevels.Thepresenceofcobblesandbouldersinthebedmaterialaidsinstabilizationofthechannelgeometry.FromRM144toRM139,abroadeningofthevalleybottomhasallowedtherivertodevelopasplitchannelwithintermittent,well-vegetatedislands.Thebankful.lstageisapproximatelyequaltothewatersurfaceelevationatthemeanannualflood.Wherethemainchannelimpingesonvalleywallsorterraces,acobblearmorlayerhasdeveloped,withatopelevationatroughlybankfullfloodstage.AtRM144,aperiglacialalluvialfanofcoarsesedimentsconfinestherivertoasinglechannel.FromRM139toRM129.5,theriverischaracterizedbyawell-definedsplit-channelconfiguration.Vegetatedislandsseparatethemainchannelfromsidechannels.Sidechannelsandsloughsoccurfrequentlyinthealluvialfloodplainandareinundatedonlyatflowsabove15,000to20,000ft3/s(425to566m3/s).Wherethemainchannelimpingesvalleyswallsorterraces,acobblearmorlayerhasdeveloped,withatopelevationatroughlybankfullfloodstage.Themainchannelbedhasbeenfrequentlyobservedtobewellarmored.PrimarytributariesinthisreachincludeIndianRiver(RM138.5),GoldCreek(RM136.8),andFourthofJulyCreek(RM131.1).Eachhasformedanalluvialfanextendingintothevalleybottom,constrictingtheSusitnatoasinglechannel.Eachconstrictionhasestablishedahydrauliccontrolpointthatregulateswatersurfaceprofilesandassociatedhydraulicparametersatvaryingdischarges.FromRM129.5toRM119,riverpatternsaresimilartothoseinthepreviousreach.ProminentcharacteristicsbetweenShermanandCurryincludethemainchannelflowingagainstthewestvalleywallandnumeroussidechannelsandsloughsalongtheeastfloodplain.ThealluvialfanatCurryconstrictstheSusitnatoasinglechannelandterminatestheabovepatterns.H-3 H-418MilesIndicatesDrainageBasinBoundary\\\\\,II,IIII/..:",,"""..."",.......\\<:7\\\,,I,II,Lowersusitno~.J/Droin~geI./Bosm_-----1---_....""~~~~~-------~~..............zoNCOFigureH.l-l.SusitnaRiverBasin.H-418MilesIndicatesDrainageBasinBoundary\\\\\,II,IIII/..:",,"""..."",.......\\<:7\\\,,I,II,Lowersusitno~.J/Droin~geI./Bosm_-----1---_....""~~~~~-------~~..............zoNCOFigureH.l-l.SusitnaRiverBasin. H-51WATANADAMSITE(MAXIMUMPOOLELEVATION=2185ItM.S.UDEVILCANYONDEVILCREEKCONFLUENCE~///////////PORTAGE/CREEK/fDEVILCANYONDAMSITE(MAXIMUMPOOLELEVATION=1455ItM.S.UINDIANRIVERNOTE:WATERSURFACEPROFILESBASEDONPRELIMINARYDATA.850125014501350750650550126130134138142146150 154158162166170174178182186600"500"CHULITNARIVER"CONFLUENCE""TALKEETNARIVERJ""400CONFLUENCl~TIDAL-lPARKSHIGHWAY./zINFLUENCE0BRIDGE(SUNSHINE)"f=300~./"«>w..JW2001001020304050607080RIVERMILE:§1150z~1050«>wd950FigureH.1-2.LongitudinalprofileofthemainstemoftheSusitnaRiver.Source:RedrawnfromExhibitE,FiguresE.2.6,E.2.7,andE.2.9.H-51WATANADAMSITE(MAXIMUMPOOLELEVATION=2185ItM.S.UDEVILCANYONDEVILCREEKCONFLUENCE~///////////PORTAGE/CREEK/fDEVILCANYONDAMSITE(MAXIMUMPOOLELEVATION=1455ItM.S.UINDIANRIVERNOTE:WATERSURFACEPROFILESBASEDONPRELIMINARYDATA.850125014501350750650550126130134138142146150 154158162166170174178182186600"500"CHULITNARIVER"CONFLUENCE""TALKEETNARIVERJ""400CONFLUENCl~TIDAL-lPARKSHIGHWAY./zINFLUENCE0BRIDGE(SUNSHINE)"f=300~./"«>w..JW2001001020304050607080RIVERMILE:§1150z~1050«>wd950FigureH.1-2.LongitudinalprofileofthemainstemoftheSusitnaRiver.Source:RedrawnfromExhibitE,FiguresE.2.6,E.2.7,andE.2.9. H-6Afaircorrelationexistsbetweenbankfullstageandmeanannualfloodthroughthisreach.Comparisonof1950and1980aerialphotographsrevealslocalizedchangesinbanklinesandislandmorphology.Thewestvalleywallisgenerallynonerodibleandhasoccasionalbedrockoutcrops.Theresistantboundaryononesideofthemainchannelhasgenerallyforcedauniformchannelconfigurationwithawell-armoredperimeter.ThewestvalleywallisrelativelystraightanduniformexceptatRMs128and125.5.Attheselocations,bedrockoutcropsdeflectthemainchanneltotheeastsideofthefloodplain.FromRM119toRM104,theriverispredominantlyaverystable,single,incisedchannelwithafewislands.Thechannelbanksarewellarmoredwithcobblesandboulders,asisthebed.Severallargebouldersoccurintermittentlyalongthemainchannelandarebelievedtohavebeentransporteddownthevalleyduringglacialicemovement.Theyprovidelocalobstructiontoflowandnavigation,butdonothavesignificantimpactonchannelmorphology.BelowTalkeetnaAttheconfluenceoftheSusitna,Chulitna,andTalkeetnarivers,thereisadramaticchangeintheSusitnafromasplit-channeltoabraided-channelpattern.Theriveremergesfromtheconfinedmiddlebasinintotheunconfinedlowlandsofthelowerbasin,enablingtheriversystemtodeveloplaterally.Highbedloadandagradientdecreasealsocontributetoestablishingthebraidedpattern.TheglacialtributariesoftheChulitnaRiveraremuchclosertotheconfluencethanaretheSusitnaglacialtributaries.AstheChulitnaRiveremergesfromanincisedcanyon20mi(32km)upstreamoftheSusitna-Chulitnaconfluence,itistransformedintoabraidedpattern,withmoderatevegetationgrowthontheintermediategravelbars.Ataboutthemidpointbetweenthecanyonandtheconfluence,theChulitnaexhibitsahighlybraidedpatternwithnovegetationonintermediategravelbars-evidenceofrecentlateralinstability.Thispatterncontinuesbeyondtheconfluence,givingtheimpressionthattheSusitnaistributarytothedominantChulitnaRiver.Thesplit-channelTalkeetnaRiverisatributarytothedominantbraidedpattern.Terracesboundthebroadfloodplain,butprovidelittlecontroloverchannelmorphology.Generalfloodplaininstabilityresultsfromthethree-riversystemstrivingtobalanceoutthecombinedflowandsedimentregime.FromRM95toRM42,downstreamfromthethree-riverconfluence,theSusitnacontinues'itsbraidedpattern,withmultiplechannelsinterlacedthroughasparselyvegetatedfloodplain.Thechannelnetworkconsistsofthemainchannel,usuallyoneortwosUbchannels,andanumberofminorchannels.Themainchannelmeandersirregularlythroughthewidegravelfloodplainandintermittentlyflowsagainstthevegetatedfloodplain.Ithasthecapabilityofmigratinglaterallywithintheactivegravelfloodplain,reworkingthegravelthatthesystempreviouslydeposited.Whenthemainchannelflowsagainstvegetatedbanks,erosionisretardedowingtothevegetationand/orbankmaterialsthataremoreresistanttoerosion.Flowinthemainchannelusuallypersiststhroughouttheentireyear.Subchannelsareusuallypositionednearoragainstthevegetatedfloodplainandaregenerallyontheoppositesideofthefloodplainfromthemainchannel.Thesubchannelsnormallybifurcatefromthemainchannelwhenitcrossesovertotheoppositesideofthefloodplainandterminatewherethemainchannelmeandersbackacrossthefloodplainandinterceptsthem.Thesubchannelshavesmallergeometricdimensionsthanthemainchannel,andtheirthalwegsaregenerallyabout5ft(1.5m)higher.Theirflowregimesaredependentonthemainchannelstageandhydraulicflowcontrolsatthepointofbifurication.Flowmayormaynotpersistthroughouttheyear.Minorchannelsarerelativelyshallow,widechannelsthattraversethegravelfloodplainsandcompletetheinterlacedbraidedpattern.Thesechannelsareveryunstableandgenerallyshortlived.Themainchannelandsubchannelsareintermittentlycontrolledlaterallywheretheyflowagainstterraces.Sincetheactivefloodplainisverywide,thepresenceofterraceshaslittlesignificanceexceptfordeterminingthegeneralorientationoftheriversystem.AnexceptionoccurswheretheterracesconstricttherivertoasinglechannelattheParksHighwaybridge.Minorchannelsreacttothebehaviorofbothofthelargerchannels.FromRM61toRM42,downstreamfromtheKashwitnaRiverconfluence,theSusitnaRiverbranchesintomultiplechannelsseparatedbyislandswithestablishedvegetation.ThisreachoftheriverisknownastheDeltaIslandsbecauseitresemblesthedistributarychannelnetworkcommontolargeriverdeltas.ThemultiplechannelsareforcedtogetherbyterracesjustupstreamofKrotoCreek(DeshkaRiver).H-6Afaircorrelationexistsbetweenbankfullstageandmeanannualfloodthroughthisreach.Comparisonof1950and1980aerialphotographsrevealslocalizedchangesinbanklinesandislandmorphology.Thewestvalleywallisgenerallynonerodibleandhasoccasionalbedrockoutcrops.Theresistantboundaryononesideofthemainchannelhasgenerallyforcedauniformchannelconfigurationwithawell-armoredperimeter.ThewestvalleywallisrelativelystraightanduniformexceptatRMs128and125.5.Attheselocations,bedrockoutcropsdeflectthemainchanneltotheeastsideofthefloodplain.FromRM119toRM104,theriverispredominantlyaverystable,single,incisedchannelwithafewislands.Thechannelbanksarewellarmoredwithcobblesandboulders,asisthebed.Severallargebouldersoccurintermittentlyalongthemainchannelandarebelievedtohavebeentransporteddownthevalleyduringglacialicemovement.Theyprovidelocalobstructiontoflowandnavigation,butdonothavesignificantimpactonchannelmorphology.BelowTalkeetnaAttheconfluenceoftheSusitna,Chulitna,andTalkeetnarivers,thereisadramaticchangeintheSusitnafromasplit-channeltoabraided-channelpattern.Theriveremergesfromtheconfinedmiddlebasinintotheunconfinedlowlandsofthelowerbasin,enablingtheriversystemtodeveloplaterally.Highbedloadandagradientdecreasealsocontributetoestablishingthebraidedpattern.TheglacialtributariesoftheChulitnaRiveraremuchclosertotheconfluencethanaretheSusitnaglacialtributaries.AstheChulitnaRiveremergesfromanincisedcanyon20mi(32km)upstreamoftheSusitna-Chulitnaconfluence,itistransformedintoabraidedpattern,withmoderatevegetationgrowthontheintermediategravelbars.Ataboutthemidpointbetweenthecanyonandtheconfluence,theChulitnaexhibitsahighlybraidedpatternwithnovegetationonintermediategravelbars-evidenceofrecentlateralinstability.Thispatterncontinuesbeyondtheconfluence,givingtheimpressionthattheSusitnaistributarytothedominantChulitnaRiver.Thesplit-channelTalkeetnaRiverisatributarytothedominantbraidedpattern.Terracesboundthebroadfloodplain,butprovidelittlecontroloverchannelmorphology.Generalfloodplaininstabilityresultsfromthethree-riversystemstrivingtobalanceoutthecombinedflowandsedimentregime.FromRM95toRM42,downstreamfromthethree-riverconfluence,theSusitnacontinues'itsbraidedpattern,withmultiplechannelsinterlacedthroughasparselyvegetatedfloodplain.Thechannelnetworkconsistsofthemainchannel,usuallyoneortwosUbchannels,andanumberofminorchannels.Themainchannelmeandersirregularlythroughthewidegravelfloodplainandintermittentlyflowsagainstthevegetatedfloodplain.Ithasthecapabilityofmigratinglaterallywithintheactivegravelfloodplain,reworkingthegravelthatthesystempreviouslydeposited.Whenthemainchannelflowsagainstvegetatedbanks,erosionisretardedowingtothevegetationand/orbankmaterialsthataremoreresistanttoerosion.Flowinthemainchannelusuallypersiststhroughouttheentireyear.Subchannelsareusuallypositionednearoragainstthevegetatedfloodplainandaregenerallyontheoppositesideofthefloodplainfromthemainchannel.Thesubchannelsnormallybifurcatefromthemainchannelwhenitcrossesovertotheoppositesideofthefloodplainandterminatewherethemainchannelmeandersbackacrossthefloodplainandinterceptsthem.Thesubchannelshavesmallergeometricdimensionsthanthemainchannel,andtheirthalwegsaregenerallyabout5ft(1.5m)higher.Theirflowregimesaredependentonthemainchannelstageandhydraulicflowcontrolsatthepointofbifurication.Flowmayormaynotpersistthroughouttheyear.Minorchannelsarerelativelyshallow,widechannelsthattraversethegravelfloodplainsandcompletetheinterlacedbraidedpattern.Thesechannelsareveryunstableandgenerallyshortlived.Themainchannelandsubchannelsareintermittentlycontrolledlaterallywheretheyflowagainstterraces.Sincetheactivefloodplainisverywide,thepresenceofterraceshaslittlesignificanceexceptfordeterminingthegeneralorientationoftheriversystem.AnexceptionoccurswheretheterracesconstricttherivertoasinglechannelattheParksHighwaybridge.Minorchannelsreacttothebehaviorofbothofthelargerchannels.FromRM61toRM42,downstreamfromtheKashwitnaRiverconfluence,theSusitnaRiverbranchesintomultiplechannelsseparatedbyislandswithestablishedvegetation.ThisreachoftheriverisknownastheDeltaIslandsbecauseitresemblesthedistributarychannelnetworkcommontolargeriverdeltas.ThemultiplechannelsareforcedtogetherbyterracesjustupstreamofKrotoCreek(DeshkaRiver). Throughthisreach,theverybroadfloodplainandchannelnetworkcanbedividedintothreecategories:(1)westernbraidedchannels,(2)easternsplitchannels,and(3)intermediatemeanderingchannels.Thewesternbraided-channelnetworkisconsideredtobethemainportionofthisverycomplexriversystem.Althoughnotsubstantiatedbyriversurveys,itappearstoconstitutethelargestflowareaandlowestthalwegelevation.ThereasonforthisisthatthewesternbraidedchannelsconstitutetheshortestdistancebetweenthepointofbifurcationandtheconfluenceoftheDeltaIslandchannels.Therefore,ithasthesteepestgradientandhighestpotentialenergyforconveyanceofwaterandsediment.FromRM42toRM0,downstreamfromtheDeltaIslands,theSusitnaRivergradientdecreasesasitapproachesCookInlet(FigureH.1-2).Therivertendstowardasplit-channelconfigurationasitadjuststothelower-energyslope.Thereareshortreacheswhereabraidedpatternemerges.DownstreamofRM20,theriverbranchesoutintodeltadistributarychannelsbeforeenteringCookInlet.TerracesconstrictthefloodplainneartheKrotoCreekconfluenceandatSusitnaStation.Furtherdownstream,theterraceshavelittleornoinfluenceontheriver.TheYentnaRiverjoinstheSusitnaatRM28andisamajorcontributorofflowandsediment.TidesinCookInletriseabove30ft(9m),controllingthewatersurfaceprofileand,tosomedegree,thesedimentregimeofthelowerriver.Ariverelevationof30ft(9m)existsnearRM20,whichcorrespondstothelocationwheretheSusitnabeginstobranchoutintoitsdeltachannels.H.l.2HabitatTypesThefluvialmorphologyoftheSusitnaRivercreatesseveraluniquephysicalhabitattypes,whichareimportanttotheaquaticbiotaofthebasin.Sevendistincthabitatshavebeenidentified(FigureH.1-3):(1)mainstemhabitat,(2)side-channelhabitat,(3)side-sloughhabitat,(4)upland-sloughhabitat,(5)tributaryhabitat,(6)tributary-mouthhabitat,and(7)lakehabitat.Differencesamongthesehabitattypesarebiologicalandphysical;thereisspecies-specific,temporal,andspatialvariabilityinutilizationpatternsofthehabitattypes(seeAppendix1.1.3),andtherearealsoimportantdifferencesinhowthequalityandquantityofvarioushabitattypeschangewithchangesinmainstemdischarge(ADFG1983;Trihey1982).MainstemHabitatThemainstemhabitatconsistsofthatportionoftheriverchannelwhichconveysstreamflowthroughouttheyear,includingbothsingle-andmultiple-channelpatterns.Watervelocitiesaregenerallyhighandsubstrateiswellarmored,consistingofboulderandcobble-sizedmaterialinagroutlikematrixofsmallgravelsandglacialsand.Suspendedsedimentconcentrationsarehighduringthesummerduetothepredominanceofglacialmeltwater(AppendixH.5.2),butturbiditydecreasessignificantlybyOctoberasstream-flowdecreases.Groundwaterandtributaryinflowsarerelativelysmallcontributorstomainstemdischargeandthephysicalcharacteristicsofmainstemhabitat.ThemainstemisicecoveredfromlateNovembertoMay.WatersurfaceelevationsforvariousWatanadischargesinthereachbetweenDeadmanCreek(RM186.8)andDevilCreek(RM162.1)arelistedinTableH.l-l.TheelevationsweredeterminedwiththeuseoftheHEC-2computerprogramentitledWaterSurfaceProfiles,developedbytheU.S.ArmyCorpsofEngineers.Thewatersurfaceelevationsatthedischargeof42,200ft3/s(1,195m3/s)wouldbesimilartothoseofthemeanannualfloodof40,800ft3/s(1,155m3/s).TheHEC-2programwasalsousedtopredictwaterlevelsforthereachbetweenDevilCanyonandTalkeetna(TableH.1-2).ThewaterlevelspresentedfortheGoldCreekflowof52,000ft3/s(1,473m3/s)wouldbeslightlyhigherthanthoseassociatedwiththemeanannualfloodof49,500ft3/s(1,402m3/s).Side-ChannelHabitatTheside-channelhabitatconveysappreciablemainstemflowduringtheopen-waterseason(June-October),becomingdewateredonlyduringlowflows.Sidechannelsareeitherwell-definedoverflowchannelsorless-well-definedchannelsthroughpartiallysubmergedgravelbarsorislands.Comparedtomainstemhabitat,sidechannelshavelowervelocities,shallowerdepths,andfinersubstrate.BedelevationsaregenerallylowerthanthemainstemstageatthemeanmonthlyflowsinJunethroughAugust,leavingthesidechannelswetteddurin9thisperiod.Icecoverformsoverthesidechannelsatthesametimeasitdoesonthemainstem;however,open-waterleadsareoftenobservedinthewinterinselectedsidechannels.Therefore,groundwaterupwellingmaybeanimportantcontributiontoside-channelflowsduringlow-flowperiods.Throughthisreach,theverybroadfloodplainandchannelnetworkcanbedividedintothreecategories:(1)westernbraidedchannels,(2)easternsplitchannels,and(3)intermediatemeanderingchannels.Thewesternbraided-channelnetworkisconsideredtobethemainportionofthisverycomplexriversystem.Althoughnotsubstantiatedbyriversurveys,itappearstoconstitutethelargestflowareaandlowestthalwegelevation.ThereasonforthisisthatthewesternbraidedchannelsconstitutetheshortestdistancebetweenthepointofbifurcationandtheconfluenceoftheDeltaIslandchannels.Therefore,ithasthesteepestgradientandhighestpotentialenergyforconveyanceofwaterandsediment.FromRM42toRM0,downstreamfromtheDeltaIslands,theSusitnaRivergradientdecreasesasitapproachesCookInlet(FigureH.1-2).Therivertendstowardasplit-channelconfigurationasitadjuststothelower-energyslope.Thereareshortreacheswhereabraidedpatternemerges.DownstreamofRM20,theriverbranchesoutintodeltadistributarychannelsbeforeenteringCookInlet.TerracesconstrictthefloodplainneartheKrotoCreekconfluenceandatSusitnaStation.Furtherdownstream,theterraceshavelittleornoinfluenceontheriver.TheYentnaRiverjoinstheSusitnaatRM28andisamajorcontributorofflowandsediment.TidesinCookInletriseabove30ft(9m),controllingthewatersurfaceprofileand,tosomedegree,thesedimentregimeofthelowerriver.Ariverelevationof30ft(9m)existsnearRM20,whichcorrespondstothelocationwheretheSusitnabeginstobranchoutintoitsdeltachannels.H.l.2HabitatTypesThefluvialmorphologyoftheSusitnaRivercreatesseveraluniquephysicalhabitattypes,whichareimportanttotheaquaticbiotaofthebasin.Sevendistincthabitatshavebeenidentified(FigureH.1-3):(1)mainstemhabitat,(2)side-channelhabitat,(3)side-sloughhabitat,(4)upland-sloughhabitat,(5)tributaryhabitat,(6)tributary-mouthhabitat,and(7)lakehabitat.Differencesamongthesehabitattypesarebiologicalandphysical;thereisspecies-specific,temporal,andspatialvariabilityinutilizationpatternsofthehabitattypes(seeAppendix1.1.3),andtherearealsoimportantdifferencesinhowthequalityandquantityofvarioushabitattypeschangewithchangesinmainstemdischarge(ADFG1983;Trihey1982).MainstemHabitatThemainstemhabitatconsistsofthatportionoftheriverchannelwhichconveysstreamflowthroughouttheyear,includingbothsingle-andmultiple-channelpatterns.Watervelocitiesaregenerallyhighandsubstrateiswellarmored,consistingofboulderandcobble-sizedmaterialinagroutlikematrixofsmallgravelsandglacialsand.Suspendedsedimentconcentrationsarehighduringthesummerduetothepredominanceofglacialmeltwater(AppendixH.5.2),butturbiditydecreasessignificantlybyOctoberasstream-flowdecreases.Groundwaterandtributaryinflowsarerelativelysmallcontributorstomainstemdischargeandthephysicalcharacteristicsofmainstemhabitat.ThemainstemisicecoveredfromlateNovembertoMay.WatersurfaceelevationsforvariousWatanadischargesinthereachbetweenDeadmanCreek(RM186.8)andDevilCreek(RM162.1)arelistedinTableH.l-l.TheelevationsweredeterminedwiththeuseoftheHEC-2computerprogramentitledWaterSurfaceProfiles,developedbytheU.S.ArmyCorpsofEngineers.Thewatersurfaceelevationsatthedischargeof42,200ft3/s(1,195m3/s)wouldbesimilartothoseofthemeanannualfloodof40,800ft3/s(1,155m3/s).TheHEC-2programwasalsousedtopredictwaterlevelsforthereachbetweenDevilCanyonandTalkeetna(TableH.1-2).ThewaterlevelspresentedfortheGoldCreekflowof52,000ft3/s(1,473m3/s)wouldbeslightlyhigherthanthoseassociatedwiththemeanannualfloodof49,500ft3/s(1,402m3/s).Side-ChannelHabitatTheside-channelhabitatconveysappreciablemainstemflowduringtheopen-waterseason(June-October),becomingdewateredonlyduringlowflows.Sidechannelsareeitherwell-definedoverflowchannelsorless-well-definedchannelsthroughpartiallysubmergedgravelbarsorislands.Comparedtomainstemhabitat,sidechannelshavelowervelocities,shallowerdepths,andfinersubstrate.BedelevationsaregenerallylowerthanthemainstemstageatthemeanmonthlyflowsinJunethroughAugust,leavingthesidechannelswetteddurin9thisperiod.Icecoverformsoverthesidechannelsatthesametimeasitdoesonthemainstem;however,open-waterleadsareoftenobservedinthewinterinselectedsidechannels.Therefore,groundwaterupwellingmaybeanimportantcontributiontoside-channelflowsduringlow-flowperiods. H-8FigureH.1-3.GeneralhabitattypesintheMiddleSusitnaRiverBasin.Source:ADFG1983,Trihey1982.1.MAINSTEMHABITAT2.SIDECHANNELHABITAT3.SIDESLOUGHHABITAT4.UPLANDSLOUGHHABITAT5.TRIBUTARYHABITAT6.TRIBUTARYMOUTHHABITATH-8FigureH.1-3.GeneralhabitattypesintheMiddleSusitnaRiverBasin.Source:ADFG1983,Trihey1982.1.MAINSTEMHABITAT2.SIDECHANNELHABITAT3.SIDESLOUGHHABITAT4.UPLANDSLOUGHHABITAT5.TRIBUTARYHABITAT6.TRIBUTARYMOUTHHABITAT H-9Tab1eH.1-1.MainChannelWaterSurfaceElevationsfromDeadmanCreektoDevilCreekPredictedbyHEC-2ModelingDeadmanCreektoDevilCreekforSelectedWatanaFlows(ft3js)RiverMile810017200267003070042200 46400162.11211.21213.51215.71216.51218.4 1219.3167.01276.3 1278.71279.91280.61281.41281.3173.11330.8 1333.0 1334.91335.71337.3 1337.9174.01340.01342.81344.2 1345.01346.01346.2176.01363.9 1366.5 1367.9 1368.5 1369.51369.8176.71370.81373.51375.11375.91377•31377.6178.81391.61394.31396.31397.21398.8 1399.2180.11410.61412.11412.9 1413.4 1414.2 1414.6181.01414.4 1416.51417.81418.3 1419.2 1419.4181.81428.81432.01434.21435.11436.6 1436.8182.11435.31437.91439.81440.71442.41442.8182.51440.7 1442.41443.81444.5 1445.71446.0182.81443.7 1445.61446.81447.4 1448.31448.5183.51449.81452.21453.81454.5 1455.71456.0183.81451.61454.11455.81456.51457.81458.0184.01453.51456.31458.11458.9 1460.3 1460.6184.21454.61457.51459.41460.2 1461.61461.8184.41456.21459.31461.3 1462.3 1464.01464.4184.81462.91465.91467.41468.11469.11469.2185.41473.0 1475.81477.41478.11479.41479.7185.91497.3 1497.9 1498.3 1498.51498.3 1499.0186.51505.3 1509.0 1510.91511.61513.51513.1186.81510.11513.01515.01515.91517.81518.2Conversion:Toconvertfromcubicfeettocubicmeters.multiplyby0.0283.Source:R&MConsultants.Inc.(1982b).H-9Tab1eH.1-1.MainChannelWaterSurfaceElevationsfromDeadmanCreektoDevilCreekPredictedbyHEC-2ModelingDeadmanCreektoDevilCreekforSelectedWatanaFlows(ft3js)RiverMile810017200267003070042200 46400162.11211.21213.51215.71216.51218.4 1219.3167.01276.3 1278.71279.91280.61281.41281.3173.11330.8 1333.0 1334.91335.71337.3 1337.9174.01340.01342.81344.2 1345.01346.01346.2176.01363.9 1366.5 1367.9 1368.5 1369.51369.8176.71370.81373.51375.11375.91377•31377.6178.81391.61394.31396.31397.21398.8 1399.2180.11410.61412.11412.9 1413.4 1414.2 1414.6181.01414.4 1416.51417.81418.3 1419.2 1419.4181.81428.81432.01434.21435.11436.6 1436.8182.11435.31437.91439.81440.71442.41442.8182.51440.7 1442.41443.81444.5 1445.71446.0182.81443.7 1445.61446.81447.4 1448.31448.5183.51449.81452.21453.81454.5 1455.71456.0183.81451.61454.11455.81456.51457.81458.0184.01453.51456.31458.11458.9 1460.3 1460.6184.21454.61457.51459.41460.2 1461.61461.8184.41456.21459.31461.3 1462.3 1464.01464.4184.81462.91465.91467.41468.11469.11469.2185.41473.0 1475.81477.41478.11479.41479.7185.91497.3 1497.9 1498.3 1498.51498.3 1499.0186.51505.3 1509.0 1510.91511.61513.51513.1186.81510.11513.01515.01515.91517.81518.2Conversion:Toconvertfromcubicfeettocubicmeters.multiplyby0.0283.Source:R&MConsultants.Inc.(1982b). H-l0TaoleH.1-2.MainChannelWaterSurfaceElevationsfromDevilCanyontoTalkeetnaPredictedbyHEC-2ModelingDevilCanyontoTalkeetnaforSelected.GoldCreekFlows(ft3/s)RiverMile9700134001700023400345005200098.6344.0344.5345.5 346.5348.0348.599.6348.6350.1350.8352.3353.1355.1100.4359.2 359.4359.7359.9360.7 362.0101.0362.7 363.4363.8364.5365.3366.8101.5366.6 367.2 367.6 368.4369.2370.8102.4373.0 373.9374.5375.6376.7378.4103.2378.1379.4380.3381.8383.4386.2104.8391.5392.5393.2 394.2395.5397.8106.7409.9 410.6411.2412.0413.1415.1108.4421.6422.8423.6424.8426.4429.2110.4437.6 438.8439.6440.8442.6445.9110.9443.8444.7445.4446.3447.8450.6111.8452.5453.2453.8454.8455.7458.0112.3455.7456.6457.2458.3459.4461.6112.7459.4460.1460.5461.4 462.3464.0113.0461.3462.1462.7463.8464.9466.6116.4485.6486.6487.4 489.0490.7493.5117.2495.5 496.2 496.7497.8499.0501.1119.2510.0511.2512.0 513.4514.9516.5119.3511.6512.5513.3514.5515.9517.5120.3520.0520.4520.8 521.8522.6524.5120.7512.7 522.6523.3524.3525.4527.2121.6530.6530.9531.1532.7533.4534.8122.6538.5539.4539.9541.5542.8544.6123.3542.9534.7544.4545.7547.1549.4124.4555.2555.8 556.3557.1558.2560.1126.1571.0571.7572.3573.3574.2575.8127.5585.3585.9586.5 587.3588.1589.4128.7595.0595.9596.5 597.6598.4599.7129.7605.2606.0606.7 607.8608.9610.8130.1612.9613.7614.1614.2615.0616.1130.5616.0616.9617.4618.0619.0620.4130.9617.7618.7619.4620.3621.6623.3131.2619.5620.5621.3622.7624.2626.6131.8627.1627.6628.0628.9629.4630.4132.9639.0639.9640.6641.8643.4645.6133.3645.8646.3646.6647.5648.2649.7134.3655.1655.9656.5657.5658.6660.4134.7659.9660.6661.2662.3663.6665.7H-l0TaoleH.1-2.MainChannelWaterSurfaceElevationsfromDevilCanyontoTalkeetnaPredictedbyHEC-2ModelingDevilCanyontoTalkeetnaforSelected.GoldCreekFlows(ft3/s)RiverMile9700134001700023400345005200098.6344.0344.5345.5 346.5348.0348.599.6348.6350.1350.8352.3353.1355.1100.4359.2 359.4359.7359.9360.7 362.0101.0362.7 363.4363.8364.5365.3366.8101.5366.6 367.2 367.6 368.4369.2370.8102.4373.0 373.9374.5375.6376.7378.4103.2378.1379.4380.3381.8383.4386.2104.8391.5392.5393.2 394.2395.5397.8106.7409.9 410.6411.2412.0413.1415.1108.4421.6422.8423.6424.8426.4429.2110.4437.6 438.8439.6440.8442.6445.9110.9443.8444.7445.4446.3447.8450.6111.8452.5453.2453.8454.8455.7458.0112.3455.7456.6457.2458.3459.4461.6112.7459.4460.1460.5461.4 462.3464.0113.0461.3462.1462.7463.8464.9466.6116.4485.6486.6487.4 489.0490.7493.5117.2495.5 496.2 496.7497.8499.0501.1119.2510.0511.2512.0 513.4514.9516.5119.3511.6512.5513.3514.5515.9517.5120.3520.0520.4520.8 521.8522.6524.5120.7512.7 522.6523.3524.3525.4527.2121.6530.6530.9531.1532.7533.4534.8122.6538.5539.4539.9541.5542.8544.6123.3542.9534.7544.4545.7547.1549.4124.4555.2555.8 556.3557.1558.2560.1126.1571.0571.7572.3573.3574.2575.8127.5585.3585.9586.5 587.3588.1589.4128.7595.0595.9596.5 597.6598.4599.7129.7605.2606.0606.7 607.8608.9610.8130.1612.9613.7614.1614.2615.0616.1130.5616.0616.9617.4618.0619.0620.4130.9617.7618.7619.4620.3621.6623.3131.2619.5620.5621.3622.7624.2626.6131.8627.1627.6628.0628.9629.4630.4132.9639.0639.9640.6641.8643.4645.6133.3645.8646.3646.6647.5648.2649.7134.3655.1655.9656.5657.5658.6660.4134.7659.9660.6661.2662.3663.6665.7 TableH.1-2continuedH-11TableH.1-2.(Continued)DevilCanyontoTalkeetnaforSelectedGoldCreekFlows(ft3/s)RiverMile97001340017000234003450052000135~4668.9 669.4 669.8 670.4671.1672.4135.7671.2672.1672.7674.1675.4677.1136.4681.2682.2683.0684.1685.3 687.3136.7684.0685.1685.8687.0688.1689.9137.0687.1688.2688.9690.5692.0694.9137.2690.6 691.6692.3693.2694.6697.0137.4693.1 694.1694.9 695.7 697.2 699.5138.2702.0702.9703.6 704.5 705.4 706.9138.5703.7 704.7705.5706.7707.8709.7138.9707.2708.1708.9 710.3711.7714.3139.4716.8 717.4717.8718.3719.1720.7140.2723.6 724.5725.2 726.3 727.3 728.9140.8733.2734.1734.8736.0737.4 739.9141.5744.0744.8 745.4746.2 747.2749.0142.1752.2 753.2753.9 755.4756.7 758.7142.3754.4755.3756.1757.6759.0 761.3143.2763.9 764.7765.2 766.2767.5769.9144.8786.0787.1788.0 789.4790.9793.3147.6818.8819.9 820.7822.1823.8 827.0148.7832.9 834.3735.3836.6838.6 841.7148.9835.1836.4837.5838.8840.9844.2149.2837.5 838.8839.8841.1843.1846.5149.3839.6840.9841.9843.3845.3848.9149.4841.5842.6843.5844.7846.9850.5149.5844.3845.1845.8 846.8 848.4851.3149.8848.4 849.4850.1851.1852.4854.6150.2850.6851.9852.8 854.0855.8858.7Conversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:R&MConsultants,Inc.(1982b).TableH.1-2continuedH-11TableH.1-2.(Continued)DevilCanyontoTalkeetnaforSelectedGoldCreekFlows(ft3/s)RiverMile97001340017000234003450052000135~4668.9 669.4 669.8 670.4671.1672.4135.7671.2672.1672.7674.1675.4677.1136.4681.2682.2683.0684.1685.3 687.3136.7684.0685.1685.8687.0688.1689.9137.0687.1688.2688.9690.5692.0694.9137.2690.6 691.6692.3693.2694.6697.0137.4693.1 694.1694.9 695.7 697.2 699.5138.2702.0702.9703.6 704.5 705.4 706.9138.5703.7 704.7705.5706.7707.8709.7138.9707.2708.1708.9 710.3711.7714.3139.4716.8 717.4717.8718.3719.1720.7140.2723.6 724.5725.2 726.3 727.3 728.9140.8733.2734.1734.8736.0737.4 739.9141.5744.0744.8 745.4746.2 747.2749.0142.1752.2 753.2753.9 755.4756.7 758.7142.3754.4755.3756.1757.6759.0 761.3143.2763.9 764.7765.2 766.2767.5769.9144.8786.0787.1788.0 789.4790.9793.3147.6818.8819.9 820.7822.1823.8 827.0148.7832.9 834.3735.3836.6838.6 841.7148.9835.1836.4837.5838.8840.9844.2149.2837.5 838.8839.8841.1843.1846.5149.3839.6840.9841.9843.3845.3848.9149.4841.5842.6843.5844.7846.9850.5149.5844.3845.1845.8 846.8 848.4851.3149.8848.4 849.4850.1851.1852.4854.6150.2850.6851.9852.8 854.0855.8858.7Conversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:R&MConsultants,Inc.(1982b). H-12H.2.1PreprojectFlowsMeanmonthlyflowsattheWatanaandDevilCanyondamsiteswereestimated,usingalineardrainagearea-flowrelationshipbetweentheGoldCreekandCantwell(VeeCanyon)gagesites(ExhibitE,Chapter2).Themonthlyflowsforeachmonthofthe32-year-modified-recordforGoldCreekandSunshinearepresentedinTablesH.2-3andH.2-4.Thevariationbetweensummerandwintermeanmonthlyflowsisgreaterthana10-to-1ratioatallstations.Thislargeseasonaldifferenceisduetothecharacteristicsofaglacialriversystem.Glacialmelt,snowmelt,andrainfallprovidethemostoftheannualriverflowduringthesummer.AcomparisonofthemaximumandminimummonthlyflowsforMaythroughSeptemberindicatedahighflowvariabilityatallstationsfromyeartoyear.AtGoldCreek,88%oftheannualstreamflowvolumeoccursduringthemonthsofMaythroughSeptember.ThemostcommonfloodsintheSusitnaRiverBasinoccurinMaytoJulyandarecomposedofsnowmeltoracombinationofsnowmeltandrainfalloveralargearea(FigureH.2-1).FloodsoccurbetweenMayandJuly,withthemajorityoccurringinJune.FloodsattributabletoheavyrainshaveoccurredinAugustandSeptember.Thesefloodsareaugmentedbysnowmeltfromhigherelevationsandglacialrunoff.Examplesoffloodhydrographsfor1964, 1967,and1970atGoldCreekandWatanaareillustratedinFigureH.2-1.ThedailyflowatCantwellandGoldCreekandthelineardrainagearea-flowrelationshipbetweenthemwasusedtodeterminetheaveragemonthlyflowsatWatana.FigureH.2-lashowsthelargestsnow-meltfloodonrecordatGoldCreek.The1967springfloodhydrographshowninFigureH.2-1bhasadailySide-SloughHabitatTheside-sloughhabitatisthemostbiologicallysignificanthabitattypeandthemostresponsivetochangesinmainstemdischarge.Thesesloughsareoverflowchannelsthatexistalongtheedgeofthefloodplain,separatedfromtheriverbywell-vegetatedbars.Anexposedalluvialbermoftenseparatestheheadofthesloughsfromthemainstemorside-channelflow.Thecontrollingstreambankelevationsattheupstreamendofthesloughsarelessthanthemainstemwatersurfaceelevationsduringmedianandhighflowperiods.Atintermediateandlowflows,thesloughsconveyclearwaterfromsmalltributariesandupwellinggroundwater(ADFG1982).Side-channelsloughsstudiedbyADFG(1983)areidentifiedinFigureH.1-4.Differencesbetweenmainstemwatersurfaceelevationsandthestreambedelevationofthesloughsarenotablygreaterattheupstreamentrancetothesloughsthanatthemouthofthesloughs.Thegradientswithinthesloughsaretypicallygreaterthantheadjacentmainstembecauseoftheirshorterthalweglengthcomparedtothemainstem.Theupstreamendofthesloughsgenerallyhasahighergradientthanthelowerend(e.g.,FigureH.1-5).Thesloughsvaryinlengthfrom2,000to6,000ft(610to1,829m).Crosssectionsofthesloughsaretypicallyrectangularwithflatbottoms.Attheheadofthesloughs,substratesaredominatedbybouldersandcobbles[8to14in(20to36cm)indiameter].Downstreamtowardthesloughmouth,thesubstrateparticlesdecreaseinsize,withgravelsandsandspredominating(FigureH.1-5).Beaversfrequentlyinhabitthesloughs.Activeandabandonedbeaverdamsarevisible.Vegetationcommonlycoversthebankstothewater'sedge,withbankcuttingandslumpingoccurringduringspringbreakupflows,highsummerflows,andwinterovertopping.Thewatersurfaceelevationofthemainstemgenerallycausesabackwatereffectatthemouthofthesloughs.Upstreamofthebackwatereffects,thesloughsfunctionlikesmallstreamsystemsconveyingwaterfromlocalrunoffandgroundwaterupwellingduringlow-flowperiodsandmainstemwaterduringhigh-flowperiodswhentheupstreamendofthesloughisovertoppedbythemainstemflow(ADFG1983).H.2FLOWREGIMESContinuoushistoricalstreamflowrecordsofvariouslength[7to32yearsthroughwateryear(WY)1981JexistatgagingstationsontheSusitnaRiveranditstributaries(TableH.2-1,FigureH.1-1).ContinuousU.S.GeologicalSurvey(USGS)historicalstreamflowrecordsexistatGoldCreekfrom1952tothepresent.BecausetheGoldCreekgagehasthelongestrecordintheSusitnaBasinandbecauseitiscentrallylocatedintheportionoftheriverthatwillreceivethelargestflowregulation,thissitewillserveasthereferencepointforevaluatingpostprojectflows.Complete30-yearstreamflowdatasets(summarizedinTableH.2-2)fortheothergagingstationsweregenerated,usingacorrelationanalysistoestimatemissingmeanmonthlyflows(ExhibitE,Chapter2).ThisanalysiswasbasedontheprogramFILLINdevelopedbytheTexasWaterDevelopmentBoard(1970).Theprocedureisamu1tisiteregressiontechnique,whichanalyzesmonthlytimeseriesdataandfillsinmissingportionsintheincompleterecords.Theprogramevaluatesthestatisticalparametersthatcharacterizethedataset(i.e.,seasonalmeans,seasonalstandarddeviations,lag-oneautocorrelationcoefficients,andmu1tisitespatialcorrelationcoefficients)andcreatesafilled-indatasetinwhichthesestatisticalparametersarepreserved.Fortheanalysis,allstreamflowdataupto1981wereused(32yearsofdataatGoldCreek).H-12H.2.1PreprojectFlowsMeanmonthlyflowsattheWatanaandDevilCanyondamsiteswereestimated,usingalineardrainagearea-flowrelationshipbetweentheGoldCreekandCantwell(VeeCanyon)gagesites(ExhibitE,Chapter2).Themonthlyflowsforeachmonthofthe32-year-modified-recordforGoldCreekandSunshinearepresentedinTablesH.2-3andH.2-4.Thevariationbetweensummerandwintermeanmonthlyflowsisgreaterthana10-to-1ratioatallstations.Thislargeseasonaldifferenceisduetothecharacteristicsofaglacialriversystem.Glacialmelt,snowmelt,andrainfallprovidethemostoftheannualriverflowduringthesummer.AcomparisonofthemaximumandminimummonthlyflowsforMaythroughSeptemberindicatedahighflowvariabilityatallstationsfromyeartoyear.AtGoldCreek,88%oftheannualstreamflowvolumeoccursduringthemonthsofMaythroughSeptember.ThemostcommonfloodsintheSusitnaRiverBasinoccurinMaytoJulyandarecomposedofsnowmeltoracombinationofsnowmeltandrainfalloveralargearea(FigureH.2-1).FloodsoccurbetweenMayandJuly,withthemajorityoccurringinJune.FloodsattributabletoheavyrainshaveoccurredinAugustandSeptember.Thesefloodsareaugmentedbysnowmeltfromhigherelevationsandglacialrunoff.Examplesoffloodhydrographsfor1964, 1967,and1970atGoldCreekandWatanaareillustratedinFigureH.2-1.ThedailyflowatCantwellandGoldCreekandthelineardrainagearea-flowrelationshipbetweenthemwasusedtodeterminetheaveragemonthlyflowsatWatana.FigureH.2-lashowsthelargestsnow-meltfloodonrecordatGoldCreek.The1967springfloodhydrographshowninFigureH.2-1bhasadailySide-SloughHabitatTheside-sloughhabitatisthemostbiologicallysignificanthabitattypeandthemostresponsivetochangesinmainstemdischarge.Thesesloughsareoverflowchannelsthatexistalongtheedgeofthefloodplain,separatedfromtheriverbywell-vegetatedbars.Anexposedalluvialbermoftenseparatestheheadofthesloughsfromthemainstemorside-channelflow.Thecontrollingstreambankelevationsattheupstreamendofthesloughsarelessthanthemainstemwatersurfaceelevationsduringmedianandhighflowperiods.Atintermediateandlowflows,thesloughsconveyclearwaterfromsmalltributariesandupwellinggroundwater(ADFG1982).Side-channelsloughsstudiedbyADFG(1983)areidentifiedinFigureH.1-4.Differencesbetweenmainstemwatersurfaceelevationsandthestreambedelevationofthesloughsarenotablygreaterattheupstreamentrancetothesloughsthanatthemouthofthesloughs.Thegradientswithinthesloughsaretypicallygreaterthantheadjacentmainstembecauseoftheirshorterthalweglengthcomparedtothemainstem.Theupstreamendofthesloughsgenerallyhasahighergradientthanthelowerend(e.g.,FigureH.1-5).Thesloughsvaryinlengthfrom2,000to6,000ft(610to1,829m).Crosssectionsofthesloughsaretypicallyrectangularwithflatbottoms.Attheheadofthesloughs,substratesaredominatedbybouldersandcobbles[8to14in(20to36cm)indiameter].Downstreamtowardthesloughmouth,thesubstrateparticlesdecreaseinsize,withgravelsandsandspredominating(FigureH.1-5).Beaversfrequentlyinhabitthesloughs.Activeandabandonedbeaverdamsarevisible.Vegetationcommonlycoversthebankstothewater'sedge,withbankcuttingandslumpingoccurringduringspringbreakupflows,highsummerflows,andwinterovertopping.Thewatersurfaceelevationofthemainstemgenerallycausesabackwatereffectatthemouthofthesloughs.Upstreamofthebackwatereffects,thesloughsfunctionlikesmallstreamsystemsconveyingwaterfromlocalrunoffandgroundwaterupwellingduringlow-flowperiodsandmainstemwaterduringhigh-flowperiodswhentheupstreamendofthesloughisovertoppedbythemainstemflow(ADFG1983).H.2FLOWREGIMESContinuoushistoricalstreamflowrecordsofvariouslength[7to32yearsthroughwateryear(WY)1981JexistatgagingstationsontheSusitnaRiveranditstributaries(TableH.2-1,FigureH.1-1).ContinuousU.S.GeologicalSurvey(USGS)historicalstreamflowrecordsexistatGoldCreekfrom1952tothepresent.BecausetheGoldCreekgagehasthelongestrecordintheSusitnaBasinandbecauseitiscentrallylocatedintheportionoftheriverthatwillreceivethelargestflowregulation,thissitewillserveasthereferencepointforevaluatingpostprojectflows.Complete30-yearstreamflowdatasets(summarizedinTableH.2-2)fortheothergagingstationsweregenerated,usingacorrelationanalysistoestimatemissingmeanmonthlyflows(ExhibitE,Chapter2).ThisanalysiswasbasedontheprogramFILLINdevelopedbytheTexasWaterDevelopmentBoard(1970).Theprocedureisamu1tisiteregressiontechnique,whichanalyzesmonthlytimeseriesdataandfillsinmissingportionsintheincompleterecords.Theprogramevaluatesthestatisticalparametersthatcharacterizethedataset(i.e.,seasonalmeans,seasonalstandarddeviations,lag-oneautocorrelationcoefficients,andmu1tisitespatialcorrelationcoefficients)andcreatesafilled-indatasetinwhichthesestatisticalparametersarepreserved.Fortheanalysis,allstreamflowdataupto1981wereused(32yearsofdataatGoldCreek). H-13LANECREEKANDSLOUGH8SLOUGH6AWHISKERSCREEKANDSLOUGHoIMILES21201910I?FigureH.1-4.Side-channelsloughsstudiedintheADFGSuHydroAquaticStudiesProgram.Source:ADFG1983.H-13LANECREEKANDSLOUGH8SLOUGH6AWHISKERSCREEKANDSLOUGHoIMILES21201910I?FigureH.1-4.Side-channelsloughsstudiedintheADFGSuHydroAquaticStudiesProgram.Source:ADFG1983. FigureH.1-5.Morphologyofatypicalside-channelslough.Source:ExhibitE.FigureE.2.21.H-1450+0040+001:::'::'1SILTANDGRAVELI:~·;·~·~'IGRAVELANDRUBBLE1.b':~.1COBBLEANDBOULDERHEADOFSLOUGHATSTATION62+27<>\\!(fIi:I",e.?-J>.Q\t.\'I?-t.J>.crlG20+0030+00DISTANCE(ttl10+00SLOUGH9/R(v'v./~S[!5ITNA-~.;:.'"62+27,1(/:2--/o~rL/Q+OB~r610590605z600oi=<t~595...JwFigureH.1-5.Morphologyofatypicalside-channelslough.Source:ExhibitE.FigureE.2.21.H-1450+0040+001:::'::'1SILTANDGRAVELI:~·;·~·~'IGRAVELANDRUBBLE1.b':~.1COBBLEANDBOULDERHEADOFSLOUGHATSTATION62+27<>\\!(fIi:I",e.?-J>.Q\t.\'I?-t.J>.crlG20+0030+00DISTANCE(ttl10+00SLOUGH9/R(v'v./~S[!5ITNA-~.;:.'"62+27,1(/:2--/o~rL/Q+OB~r610590605z600oi=<t~595...Jw Table H.2-1.USGS Gaging Stations for the Susitna River Basin USGS Gage Sus itna Drainage Periods of Record Station Name Number River Mile Area (mi 2)Streamflow (Continuous) Susitna River near Denali 15291000 290.8 950 5/57-9/66.11/68-Present Susitna River near Cantwell (Vee Canyon)15291500 223.1 4.140 5/61-9/72.5/80-Present Susitan River at Gold Creek 15292000 136.6 6.160 8/49-Present :c Susitna River at Sunshine 15292780 83.9 11.100 5/81-Present I...... un Susitna River at Susitna Station 15294350 25.8 19.400 10/74-Present Maclaren River near Paxson 15291200 259.8 280 6/58-Present Chulitna River near Talkeetna 15292400 98.0 2.570 2/58-9/72.5/80-Present Talkeetna River near Talkeetna 15291500 97.0 2.006 6/64-Present Skwentna River near Skwentna 15294300 28.0 2.250 10/59-Present Yentna River near Susitna Station 15294345 28.0 6.180 10/80-Present Conversion:To convert from square miles to square kilometers.multiply by 2.590. Source:Exhibit E.Table E.2.2. Table H.2-1.USGS Gaging Stations for the Susitna River Basin USGS Gage Sus itna Drainage Periods of Record Station Name Number River Mile Area (mi 2)Streamflow (Continuous) Susitna River near Denali 15291000 290.8 950 5/57-9/66.11/68-Present Susitna River near Cantwell (Vee Canyon)15291500 223.1 4.140 5/61-9/72.5/80-Present Susitan River at Gold Creek 15292000 136.6 6.160 8/49-Present :c Susitna River at Sunshine 15292780 83.9 11.100 5/81-Present I...... un Susitna River at Susitna Station 15294350 25.8 19.400 10/74-Present Maclaren River near Paxson 15291200 259.8 280 6/58-Present Chulitna River near Talkeetna 15292400 98.0 2.570 2/58-9/72.5/80-Present Talkeetna River near Talkeetna 15291500 97.0 2.006 6/64-Present Skwentna River near Skwentna 15294300 28.0 2.250 10/59-Present Yentna River near Susitna Station 15294345 28.0 6.180 10/80-Present Conversion:To convert from square miles to square kilometers.multiply by 2.590. Source:Exhibit E.Table E.2.2. Table H.2-2.Maximum,Mean,and Minimum Monthly Flows (ft 3/s)in the Simulated,32-year Data Set for the Susitna River Basint 1-t3 Gaging Station Month Dena 1i Cantwe 11 Watana Devil Canyon Gold Creek Sunshine Susitna Mac1 aren Chulitna Talkeetna Skwentna Oct Max 2,165 5,472 6,458 7,518 8,212 18,555 58,640 734 9,314 4,438 7,254 Mean 1,165 3,149 4,513 5,312 5,757 13,906 31,102 418 5,040 2,720 4,329 Min 528 1,638 2,403 2,867 3,124 18,593 15,940 249 2,898 1,450 1,929 Nov Max 878 2,487 3,525 3,955 4,192 9,400 31,590 370 3,277 1,786 4,195 Mean 500 1,460 2,052 2,383 2,568 6,104 13,361 182 2,083 1,209 1,867 Min 192 780 1,021 1,146 1,215 3,978 6,606 95 1,236 765 678 :c 575 1,658 2,259 2,905 3,264 6,137 15,081 246 2,143 1,239 2,871 IDecMax-' Mean 315 951 1,405 1,652 1,793 4,249 8,426 117 1,487 846 1,295 0'> Min 146 543 709 810 866 2,650 4,279 49 891 515 624 Jan Max 651 1,694 1,780 2,212 2,452 4,739 12,669 162 1,673 1,001 2,829 Mean 248 850 1,157 1,352 1,463 3,550 7,971 99 1,288 682 1,068 Min 85 437 619 687 724 2,218 5.032 44 974 459 600 Feb Max 422 1,200 1,560 1,836 2,028 4,057 11 ,532 140 1,414 805 1,821 Mean 206 706 979 1,147 1,243 3,009 7,117 81 1,092 568 911 Min 64 426 602 682 723 2,082 4,993 42 820 401 490 Mar Max 290 1,273 1,560 1,779 1,900 3,898 9,193 121 1,300 743 1,352 Mean 192 659 898 1,042 1,123 2,683 6,397 74 979 491 826 Min 42 408 569 664 713 2,013 4,910 36 738 379 522 Apr Max 415 1,702 1,965 2,405 2,650 5,109 12,030 145 1,600 1,038 2,138 Mean 231 835 1,113 1,282 1,377 3,257 7,242 86 1,194 573 1,088 Min 43 465 609 697 745 2,205 5,531 50 700 371 607 Table H.2-2.Maximum,Mean,and Minimum Monthly Flows (ft 3/s)in the Simulated,32-year Data Set for the Susitna River Basint 1-t3 Gaging Station Month Dena 1i Cantwe 11 Watana Devil Canyon Gold Creek Sunshine Susitna Mac1 aren Chulitna Talkeetna Skwentna Oct Max 2,165 5,472 6,458 7,518 8,212 18,555 58,640 734 9,314 4,438 7,254 Mean 1,165 3,149 4,513 5,312 5,757 13,906 31,102 418 5,040 2,720 4,329 Min 528 1,638 2,403 2,867 3,124 18,593 15,940 249 2,898 1,450 1,929 Nov Max 878 2,487 3,525 3,955 4,192 9,400 31,590 370 3,277 1,786 4,195 Mean 500 1,460 2,052 2,383 2,568 6,104 13,361 182 2,083 1,209 1,867 Min 192 780 1,021 1,146 1,215 3,978 6,606 95 1,236 765 678 :c Dec Max 575 1,658 2,259 2,905 3,264 6,137 15,081 246 2,143 1,239 2,871 I -' Mean 315 951 1,405 1,652 1,793 4,249 8,426 117 1,487 846 1,295 0'> Min 146 543 709 810 866 2,650 4,279 49 891 515 624 Jan Max 651 1,694 1,780 2,212 2,452 4,739 12,669 162 1,673 1,001 2,829 Mean 248 850 1,157 1,352 1,463 3,550 7,971 99 1,288 682 1,068 Min 85 437 619 687 724 2,218 5.032 44 974 459 600 Feb Max 422 1,200 1,560 1,836 2,028 4,057 11 ,532 140 1,414 805 1,821 Mean 206 706 979 1,147 1,243 3,009 7,117 81 1,092 568 911 Min 64 426 602 682 723 2,082 4,993 42 820 401 490 Mar Max 290 1,273 1,560 1,779 1,900 3,898 9,193 121 1,300 743 1,352 Mean 192 659 898 1,042 1,123 2,683 6,397 74 979 491 826 Min 42 408 569 664 713 2,013 4,910 36 738 379 522 Apr Max 415 1,702 1,965 2,405 2,650 5,109 12,030 145 1,600 1,038 2,138 Mean 231 835 1,113 1,282 1,377 3,257 7,242 86 1,194 573 1,088 Min 43 465 609 697 745 2,205 5,531 50 700 371 607 Table H.2-2.(Continued) Gaging Station Month Denali Cantwell Watana Devil Canyon Gold Creekt l Sunshinet2 Susitna Maclaren Chulitna Talkeetna Skwentna May Max Mean Min 4,259 2,306 629 13,751 7,473 1,915 15,973 19,777 21,890 50,302 94,143 2,131 20,025 8,840 22,370 10,398 12,230 13,277 27,955 61,376 832 9,519 4,150 8,555 2,857 3,428 3,7j~_8,§45 29,8QQ.208 ,355 1,694 1,635 June Max Mean Min 12,210 7,532 4,647 34,630 17,567 9,909 42,842 22,913 13,233 47,816 25,938 14,710 50,580 27,658 15,500 110,073 176,219 4,297 40,330 19,045 40,356 63,810 123,830 2,888 22,892 11,416 18,462 39,3JJ 67,83El 1,751 15,587 5,207 10,650 July Max Mean Min 12,110 9,688 6,756 22,790 28,767 32,388 34,450 85,600 181,400 4,649 35,570 15,410 28,620 16,873 20,778 23,101 24,383 64,538 134,130 3,241 27,044 11,118 16,997 12,220 14,844 __15,6~.16,lOO 45,?§Z 102,l?L 2,441 20,820 7,080 11,670 ::r: I..... --.J 31,435 35,270 38,538 84,940 159,600 4,122 33,670 18,033 20,590 18,431 20,709 21,996 56,642 112,851 2,644 22,732 10,459 13,335 7,772 8,484 8,879 .24,656 62,368 __974 Jl,300 __3,787 7,471 22,760 14,614 6,597 3,651 7,962 9,833 10,947 11,565 28,226 63,159 1,276 12,114 5,276 10,024 2,885 6,184 7,986 9,084 9,703 23,611 48,873 998 9,045 4,226 6,622 2,127 4,159 4,712 5,352 5,.596 14,l.5.5.31,42El 693 6,078 2,233 4,939 6,955 12,910 17,206 19,799 21,240 53,703 104,218 2,439 23,260 10,610 13,371 3,334 7,969 10,670 12,276 13,175 32,169 66,790 1,167 11,956 6,084 8,371 1,194 3,376 4,260 4,796 5,_093 .14,268__.34,085.470 6,424 070 3,783 12,010 8,431 3,919 To convert from cubic feet to cubic meters,multiply by 0.0283. t l Gold Creek data are not filled,since 32 years of record are available. t 2Sunshine discharge for WY 1980 and October-April WY 1981 were computed from Gold Creek,Talkeetna,and Chulitna discharges for the same period. Aug Max Mean Min- Sep Max Mean Min Ann Max Mean Min Conversion: Table H.2-2.(Continued) Gaging Station Month Dena 1i Cantwell Watana Devil Canyon Gold Creekt l Sunshinet2 Susitna Maclaren Chulitna Talkeetna Skwentna May Max 4,259 13,751 15,973 19,777 21,890 50,302 94,143 2,131 20,025 8,840 22,370 Mean 2,306 7,473 10,398 12,230 13,277 27,955 61,376 832 9,519 4,150 8,555 Min 629 1,915 2,857 3,428 3,745 8,645 29,809 208 2,355 1,694 1,635 June Max 12,210 34,630 42,842 47,816 50,580 110,073 176,219 4,297 40,330 19,045 40,356 Mean 7,532 17,567 22,913 25,938 27,658 63,810 123,830 2,888 22,892 11,416 18,462 Min 4,647 9,909 13,233 14,710 15,500 39,311 67,838 1,751 15,587 5,207 10,650 July Max 12,110 22,790 28,767 32,388 34,450 85,600 181,400 4,649 35,570 15,410 28,620 Mean 9,688 16,873 20,778 23,101 24,383 64,538 134,130 3,241 27,044 11,118 16,997 ::r: I Min 6,756 12,220 14,844 15,651 16,100 45,267 102,121 2,441 20,820 7,080 11 ,670 ..... --.J Aug Max 12,010 22,760 31,435 35,270 38,538 84,940 159,600 4,122 33,670 18,033 20,590 Mean 8,431 14,614 18,431 20,709 21,996 56,642 112,851 2,644 22,732 10,459 13,335 Min 3,919 6,597 7,772 8,484 8,879 24,656 62,368 974 11 ,300 3,787 7,471 Sep Max 6,955 12,910 17,206 19,799 21,240 53,703 104,218 2,439 23,260 10,610 13,371 Mean 3,334 7,969 10,670 12,276 13,175 32,169 66,790 1,167 11,956 6,084 8,371 Min 1,194 3,376 4,260 4,796 5,093 14,268 34,085 470 6,424 2,070 3,783 Ann Max 3,651 7,962 9,833 10,947 11,565 28,226 63,159 1,276 12,114 5,276 10,024 Mean 2,885 6,184 7,986 9,084 9,703 23,611 48,873 998 9,045 4,226 6,622 Min 2,127 4,159 4,712 5,352 5,596 14,355 31,428 693 6,078 2,233 4,939 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. t l Gold Creek data are not filled,since 32 years of record are available. t 2Sunshine discharge for WY 1980 and October-April WY 1981 were computed from Gold Creek,Talkeetna,and Chulitna discharges for the same period. Table H.2-3.Historical Monthly Flows (ft 3/s)at Gold Creek Including Adjusted Data for WY 1969 Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annua 1 1 6335 2583 1439 1027 788 726 870 11510 19600 22600 19880 8301 8032.1 2 3848 1300 1100 960 820 740 1617 14090 20790 22570 19670 21240 9106.0 3 5571 2744 1900 1600 1000 880 920 5419 32370 26390 20920 14480 9552.1 4 8202 3497 1700 1100 820 820 1615 19270 27320 20200 20610 15270 10090.4 5 5604 2100 1500 1300 1000 780 1235 17280 25250 20360 26100 12920 9681.6 6 5370 2760 2045 1794 1400 1100 1200 9319 29860 27560 25750 14290 10256.4 7 4951 1900 1300 980 970 940 950 17660 33340 31090 24530 18330 11473.3 8 5806 3050 2142 1700 1500 1200 1200 13750 30160 23310 20540 19800 10384.1 9 8212 3954 3264 1965 1307 1148 1533 12900 25700 22880 22540 7550 9476.4 10 4811 2150 1513 1448 1307 980 1250 15990 23320 25000 31180 16920 10559.9 11 6558 2850 2200 1845 1452 1197 1300 15780 15530 22980 23590 20510 9712.3 12 7794 3000 2694 2452 1754 1810 2650 17360 29450 24570 22100 13370 10809.3 13 5916 2700 2100 1900 1500 1400 1700 12590.43270 25850 23550 15890 11565.2 14 6723 2800 2000 1600 1500 1000 830 19030 26000 34400 23670 12320 11072.9 15 6449 2250 1494 1048 966 713 745 4307 50580 22950 16440 9571 9799.6 16 6291 2799 1211 960 860 900 1360 12990 25720 27840 21120 19350 10168.8 17 7205 2098 1631 1400 1300 1300 1775 9645 32950 19860 21830 11750 9431.8 18 4163 1600 1500 1500 1400 1200 1167 15480 29510 26800 32620 16870 11218.5 :J: I1949002353205519811900 1900 1910 16180 31550 26420 17170 8816 9810.6 ~ 20t l 4272 1906 1330 1086 922 833 1022 9852 20523 18093 16322 9776 7200.1 00 21 3124 1215 866 824 768 776 1080 11380 18630 22660 19980 9121 7591.2 22 5288 3407 2290 1442 1036 950 1082 3745 32930 23950 31910 14440 10251.0 23 5847 3093 2510 2239 2028 1823 1710 21890 34430 22770 19290 12400 10885.5 24 4826 2253 1465 1200 1200 1000 1027 8235 27800 18250 20290 9074 8086.2 25 3733 1523 1034 874 777 724 992 16180 17870 18800 16220 12250 7631.0 26 3739 1700 1603 1516 1471 1400 1593 15350 32310 27720 18090 16310 10275.4 27 7739 1993 1081 974 950 900 1373 12620 24380 18940 19800 6881 8189.3 28 3874 2650 2403 1829 1618 1500 1680 12680 37970 22870 19240 12640 10109.0 29 7571 3525 2589 2029 1668 1605 1702 11950 19050 21020 16390 8607 8194.5 30 4907 2535 1681 1397 1286 1200 1450 13870 24690 28880 20460 10770 9489.3 31 7311 4192 2416 1748 1466 1400 1670 12060 29080 32660 20960 13280 10747.7 32 7725 3986 1773 1454 1236 1114 1368 13317 18143 32000 38538 13171 11255.3 Max 8212 4192 3264 2452 2028 1900 2650 21890 50580 34400 38538 21240 11565.2 Min 3124 1215 866 824 768 713 745 3745 15530 18093 16220 6881 7200.1 Mean 5771 2577 1807 1474 1249 1124 1362 13240 27815 24445 22228 13321 9753.3 t 1uriginal data for WY 1969 (year 20),October 1969 through-September 1970,were 3822,1630,882,724, 723,816,1510,11050, 15500, 16100,8879,5093 ft 3/s,respectively,with an annual average flow of 5600 ft 3/s. Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.8. Table H.2-3.Historical Monthly Flows (ft 3/s )at Gold Creek Including Adjusted Data for WY 1969 Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annua 1 1 6335 2583 1439 1027 788 726 870 11510 19600 22600 19880 8301 8032.1 2 3848 1300 1100 960 820 740 1617 14090 20790 22570 19670 21240 9106.0 3 5571 2744 1900 1600 1000 880 920 5419 32370 26390 20920 14480 9552.1 4 8202 3497 1700 1100 820 820 1615 19270 27320 20200 20610 15270 10090.4 5 5604 2100 1500 1300 1000 780 1235 17280 25250 20360 26100 12920 9681.6 6 5370 2760 2045 1794 1400 1100 1200 9319 29860 27560 25750 14290 10256.4 7 4951 1900 1300 980 970 940 950 17660 33340 31090 24530 18330 11473.3 8 5806 3050 2142 1700 1500 1200 1200 13750 30160 23310 20540 19800 10384.1 9 8212 3954 3264 1965 1307 1148 1533 12900 25700 22880 22540 7550 9476.4 10 4811 2150 1513 1448 1307 980 1250 15990 23320 25000 31180 16920 10559.9 11 6558 2850 2200 1845 1452 1197 1300 15780 15530 22980 23590 20510 9712.3 12 7794 3000 2694 2452 1754 1810 2650 17360 29450 24570 22100 13370 10809.3 13 5916 2700 2100 1900 1500 1400 1700 12590.43270 25850 23550 15890 11565.2 14 6723 2800 2000 1600 1500 1000 830 19030 26000 34400 23670 12320 11072.9 15 6449 2250 1494 1048 966 713 745 4307 50580 22950 16440 9571 9799.6 16 6291 2799 1211 960 860 900 1360 12990 25720 27840 21120 19350 10168.8 17 7205 2098 1631 1400 1300 1300 1775 9645 32950 19860 21830 11750 9431.8 18 4163 1600 1500 1500 1400 1200 1167 15480 29510 26800 32620 16870 11218.5 :J: I 19 4900 2353 2055 1981 1900 1900 1910 16180 31550 26420 17170 8816 9810.6 0020tl427219061330 1086 922 833 1022 9852 20523 18093 16322 9776 7200.1 21 3124 1215 866 824 768 776 1080 11380 18630 22660 19980 9121 7591.2 22 5288 3407 2290 1442 1036 950 1082 3745 32930 23950 31910 14440 10251.0 23 5847 3093 2510 2239 2028 1823 1710 21890 34430 22770 19290 12400 10885.5 24 4826 2253 1465 1200 1200 1000 1027 8235 27800 18250 20290 9074 8086.2 25 3733 1523 1034 874 777 724 992 16180 17870 18800 16220 12250 7631.0 26 3739 1700 1603 1516 1471 1400 1593 15350 32310 27720 18090 16310 10275.4 27 7739 1993 1081 974 950 900 1373 12620 24380 18940 19800 6881 8189.3 28 3874 2650 2403 1829 1618 1500 1680 12680 37970 22870 19240 12640 10109.0 29 7571 3525 2589 2029 1668 1605 1702 11950 19050 21020 16390 8607 8194.5 30 4907 2535 1681 1397 1286 1200 1450 13870 24690 28880 20460 10770 9489.3 31 7311 4192 2416 1748 1466 1400 1670 12060 29080 32660 20960 13280 10747.7 32 7725 3986 1773 1454 1236 1114 1368 13317 18143 32000 38538 13171 11255.3 Max 8212 4192 3264 2452 2028 1900 2650 21890 50580 34400 38538 21240 11565.2 Min 3124 1215 866 824 768 713 745 3745 15530 18093 16220 6881 7200.1 Mean 5771 2577 1807 1474 1249 1124 1362 13240 27815 24445 22228 13321 9753.3 t 1Uriginal data for WY 1969 (year 20),October 1969 through-September 1970,were 3822,1630,882,724, 723,816,1510,11050, 15500, 16100,8879,5093 ft 3/s,respectively,with an annual average flow of 5600 ft 3/s. Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.8. Table H.2-4.Historical Monthly Flows (ft3/s)Estimated at the Sunshine USGS Gaging Station Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annual 1 14003 5639 3611 2748 2276 2033 2311 22418 45613 59179 54849 27734 20347.1 2 12226 4712 3804 2930 2435 2144 3563 42196 58872 69474 58356 51069 26136.1 3 13713 5702 3782 3470 2511 2282 2357 11258 68738 64937 53363 32057 22117.5 4 17394 7199 4080 2818 2343 2317 4292 50302 64075 54231 49954 33737 24544.3 5 13227 5092 3977 3667 2889 2423 3204 32595 54805 53386 57701 28376 21921.8 6 12188 6340 4313 3927 3189 2577 2658 21758 69686 70894 77692 35385 26041.6 7 11011 4367 3161 2612 2286 2209 2244 33157 73941 80569 69034 44495 27588.4 8 15252 7029 4907 4006 3471 2844 2907 34140 79153 62302 53243 48121 26550.7 9 18399 9032 6139 4067 2996 2643 3399 27759 60752 59850 56902 20098 22824.2 10 11578 5331 3592 3387 3059 2280 2895 29460 64286 67521 71948 36915 25345.8 11 15131 6415 4823 4059 3201 2675 2928 34802 39311 58224 55315 43086 22651.3 12 16996 6109 5504 4739 3478 3480 5109 32438 60886 63640 60616 36071 25075.2 13 14579 6657 4820 4222 3342 2975 3581 24520 87537 67756 61181 38711 26766.6 14 13956 6052 4690 4074 3621 2399 2025 35245 56629 78219 52938 29182 24260.8 15 18555 5907 3533 2797 2447 2013 2381 8645 111073 58836 46374 23267 23864.9 16 15473 7472 4536 3373 2962 2818 3435 24597 58488 65042 56375 53703 24971.3 ::c171820853213965 3404 3009 2875 3598 16479 69569 55243 62007 30156 22934.7 I 18 11551 4295 3856 3698 3294 2793 2639 32912 66162 77125 82747 37379 27566.1 ~ ~ 19 10706 5413 4563 4181 3986 3898 4359 36961 76770 69735 46730 20885 24149.1 20 10524 4481 3228 2689 1731 2022 2442 21306 49349 48565 42970 24832 17950.7 21 9416 3978 2848 2600 2448 2382 3150 25687 47602 60771 54926 27191 20393.7 22 12264 7467 4930 3325 2514 2351 2640 10652 76208 64787 74519 32402 24629.0 23 14313 6745 4922 4257 3801 3335 3210 36180 66856 62292 51254 34156 24407.1 24 13588 6018 4030 3312 2984 2646 2821 18215 59933 51711 51085 25238 20235.8 25 11284 4699 3524 2882 2519 2220 2916 31486 43713 51267 43222 29114 19195.1 26 12302 4938 3777 3546 2990 2810 3160 29380 72836 75692 51678 35567 25023.2 27 15565 4238 2734 2507 2355 2281 3294 22875 56366 55506 52155 18502 20000.7 28 10620 5888 5285 4231 3640 3171 3537 27292 87773 62194 55157 32719 25221.6 29 17399 7130 5313 4213 3227 3002 3542 22707 48044 57930 42118 22742 19910.2 30 11223 5648 4308 3674 3206 2963 3704 33876 59849 71774 48897 26790 23144.3 31 17688 9400 5189 4218 3699 3519 4627 26907 65084 84273 50624 27835 25416.2 32 16580 8195 4805 4433 4057 3412 4292 36160 50890 85600 84940 32460 28226.1 Max 18555 9400 6139 4739 4057 3898 5109 50302 111073 85600 84940 53703 28226.1 Min 9416 3978 2734 2507 1731 2013 2025 8645 39311 48565 42118 18502 17950.7 Mean 13966 6028 4267 3565 2999 2681 3226 27949 64089 64641 57215 32499 23731.6 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Table E.2.9. Table H.2-4.Historical Monthly Flows (ft3/s)Estimated at the Sunshine USGS Gaging Station Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annual 1 14003 5639 3611 2748 2276 2033 2311 22418 45613 59179 54849 27734 20347.1 2 12226 4712 3804 2930 2435 2144 3563 42196 58872 69474 58356 51069 26136.1 3 13713 5702 3782 3470 2511 2282 2357 11258 68738 64937 53363 32057 22117.5 4 17394 7199 4080 2818 2343 2317 4292 50302 64075 54231 49954 33737 24544.3 5 13227 5092 3977 3667 2889 2423 3204 32595 54805 53386 57701 28376 21921.8 6 12188 6340 4313 3927 3189 2577 2658 21758 69686 70894 77692 35385 26041.6 7 11011 4367 3161 2612 2286 2209 2244 33157 73941 80569 69034 44495 27588.4 8 15252 7029 4907 4006 3471 2844 2907 34140 79153 62302 53243 48121 26550.7 9 18399 9032 6139 4067 2996 2643 3399 27759 60752 59850 56902 20098 22824.2 10 11578 5331 3592 3387 3059 2280 2895 29460 64286 67521 71948 36915 25345.8 11 15131 6415 4823 4059 3201 2675 2928 34802 39311 58224 55315 43086 22651.3 12 16996 6109 5504 4739 3478 3480 5109 32438 60886 63640 60616 36071 25075.2 13 14579 6657 4820 4222 3342 2975 3581 24520 87537 67756 61181 38711 26766.6 14 13956 6052 4690 4074 3621 2399 2025 35245 56629 78219 52938 29182 24260.8 15 18555 5907 3533 2797 2447 2013 2381 8645 111073 58836 46374 23267 23864.9 16 15473 7472 4536 3373 2962 2818 3435 24597 58488 65042 56375 53703 24971.3 ::c171820853213965 3404 3009 2875 3598 16479 69569 55243 62007 30156 22934.7 I 18 11551 4295 3856 3698 3294 2793 2639 32912 66162 77125 82747 37379 27566.1 ~ 19 10706 5413 4563 4181 3986 3898 4359 36961 76770 69735 46730 20885 24149.1 20 10524 4481 3228 2689 1731 2022 2442 21306 49349 48565 42970 24832 17950.7 21 9416 3978 2848 2600 2448 2382 3150 25687 47602 60771 54926 27191 20393.7 22 12264 7467 4930 3325 2514 2351 2640 10652 76208 64787 74519 32402 24629.0 23 14313 6745 4922 4257 3801 3335 3210 36180 66856 62292 51254 34156 24407.1 24 13588 6018 4030 3312 2984 2646 2821 18215 59933 51711 51085 25238 20235.8 25 11284 4699 3524 2882 2519 2220 2916 31486 43713 51267 43222 29114 19195.1 26 12302 4938 3777 3546 2990 2810 3160 29380 72836 75692 51678 35567 25023.2 27 15565 4238 2734 2507 2355 2281 3294 22875 56366 55506 52155 18502 20000.7 28 10620 5888 5285 4231 3640 3171 3537 27292 87773 62194 55157 32719 25221.6 29 17399 7130 5313 4213 3227 3002 3542 22707 48044 57930 42118 22742 19910.2 30 11223 5648 4308 3674 3206 2963 3704 33876 59849 71774 48897 26790 23144.3 31 17688 9400 5189 4218 3699 3519 4627 26907 65084 84273 50624 27835 25416.2 32 16580 8195 4805 4433 4057 3412 4292 36160 50890 85600 84940 32460 28226.1 Max 18555 9400 6139 4739 4057 3898 5109 50302 111073 85600 84940 53703 28226.1 Min 9416 3978 2734 2507 1731 2013 2025 8645 39311 48565 42118 18502 17950.7 Mean 13966 6028 4267 3565 2999 2681 3226 27949 64089 64641 57215 32499 23731.6 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Table E.2.9. H-208obb~="=:bJd=l:=b!:,±:::t~~~4-:~~~~~9J~~D~EC~MAYJUNEJULYMONTHNOTE:TIMESCALEISININCREMENTSOF10DAYS.FigureH.2-1.RepresentatiaveannualhydrographsattheWatanadamsiteandtheGoldCreekgagingstationfortwowetyearswithspring(1964)andfall(1967)floodsandforonedryyear(1970).Source:ExhibitE,FiguresE.2.24. E.2.25.andE.2.26.88,'I'I',I--r-rrr80721964(0)~64----WATANAFLOW.;:056-GOLDCREEK,0FLOW,g48w'"400::<J:I32uen02416808880721967(b)~64o560g48w'"400::<J:is32eno2416808880721970(c)~641:5600g48~400::<J:32IUeno2416H-208obb~="=:bJd=l:=b!:,±:::t~~~4-:~~~~~9J~~D~EC~MAYJUNEJULYMONTHNOTE:TIMESCALEISININCREMENTSOF10DAYS.FigureH.2-1.RepresentatiaveannualhydrographsattheWatanadamsiteandtheGoldCreekgagingstationfortwowetyearswithspring(1964)andfall(1967)floodsandforonedryyear(1970).Source:ExhibitE,FiguresE.2.24. E.2.25.andE.2.26.88,'I'I',I--r-rrr80721964(0)~64----WATANAFLOW.;:056-GOLDCREEK,0FLOW,g48w'"400::<J:I32uen02416808880721967(b)~64o560g48w'"400::<J:is32eno2416808880721970(c)~641:5600g48~400::<J:32IUeno2416 H-21peakequaltothemeanannualdailyfloodpeak.Inaddition,thesummerdailyfloodpeakof76,000ft3/s(2,152m3/s)isthesecondlargestfloodpeakatGoldCreekonrecord.Recurrenceintervalsforhighflowspersistingfor7consecutivedaysareshowninFigureH.2-2.ThemaximumrecordedinstantaneousfloodpeaksforDenali,Cantwell,andMaclaren,recordedbytheUSGS,arepresentedinTableH.2-5.Probable-maximum-flood(PMF)studieswereconductedforboththeWatanaandDevilCanyondamsitesforuseinthedesignofprojectspillwaysandrelatedfacilities(ExhibitE,Chapter2).ThePMFsweredeterminedbyusingtheSSARRwatershedmodeldevelopedbythePortlandDistrict,U.S.ArmyCorpsofEngineersandarebasedonSusitnaBasinclimaticdataandhydrology.Theprobablemaximumprecipitationwasderivedfromamaximizationstudyofhistoricalstorms.ThestudiesindicatethatthePMFpeakattheWatanadamsiteis326,000ft3/s(9,232m3/s).Theflow-durationcurvesbasedonpreprojectmeandailyflowsareshowninFigureH.2-3.Inthemajorityofcases,thethree-parameterlognormaldistributionprovidesthebestfittothedata(R&MandHarrison1981).Theshapeofthemonthlyandannualflowdurationcurvesissimilarforeachofthestationswithinthebasinandisindicativeofflowfromnorthernglacialrivers(ExhibitE,Chapter2).Streamflowislowinthewintermonths,withlittlevariationinflowandnounusualpeaks.Groundwatercontributionsaretheprimarysourceofthesmallbutrelativelyconstantwinterflows.FlowbeginstoincreaseslightlyinAprilasbreakupapproaches.PeakflowsinMayareanorderofmagnitudegreaterthaninApril.FlowinMayalsoshowsthegreatestvariationforanymonth,aslowflowsmaycontinueintoMaybeforethehighsnow-melt/breakupflowsoccur.Junehasthehighestpeaksandthehighestmeaianflowforthemiddleandupperbasinstations.ThemonthsofJulyandAugusthaverelativelyflatflow-durationcurves.Thissituationisindicativeofriverswithstrongbaseflowcharacteristics,asisthecaseontheSusitnawithitscontributionsfromsnowandglacialmeltduringthesummer.MorevariabilityofflowisevidentinSeptemberandOctoberascoolerweatherbecomesmoreprevalentaccompaniedbyadecreaseinglacialmeltandhencedischarge.Fromtneflow-durationcurveforGoldCreek(FigureH.2-3),itcanbeseenthatflowsatGoldCreekarelessthan20,000ft3/s(566m3/s)fromOctoberthroughApril.AsaresultofthespringbreakupinMay,flowsof20,000ft3/sareexceeded3~%ofthetime.DuringJuneandJuly,thepercentoftimeGoldCreekflowsexceed20,000ft/sincreasesto80%.Thispercentagedecreasesto65%inAugustandfurtherdecreasestoonlyabout15%inSeptember.Onanannualbasis,aflowof20,000ft3/sisexceeded20%ofthetime.The7-daylow-flowvaluesdeterminedforselectedmonthsatGoldCreekareshowninFigureH.2-4mayexhibitssubstantialvariability.BothlowwinterflowsandhighbreakupflowsusuallyoccurduringMay,andthussignificantchangesoccurfromyeartoyear.JuneexhibitsmorevariabilitythanJuly.FlowvariabilityincreasesagainintheAugustthroughOctoberperiod.HeavyrainstormsoftenoccurinAugust,with28%oftheannualfloodsoccurringinthismonth.Flowvariabilityinthewintermonthsisreducedconsiderably,reflectingthelowbaseflow.GlacialEffectsTheglaciatedportionsoftheSusitnaRiverBasinaboveGoldCreekplayasignificantroleinthehydrologyofthearea.LocatedonthesouthernslopesoftheAlaskaRange,theglaciatedregionsreceivethegreatestamountofsnowandrainfallinthebasin.Duringthesummermonths,theseregi~nscontr~butesignificantamountsofsnowandglacialmelt.Theglacierscoverabout290mi(750km)andactasreservoirsthatproducemostofthewaterinthebasinaboveGoldCreekduringdroughtperiods.ThedrainageareaupstreamoftheDenaliandMaclarengagescomprises20%ofthebasinaboveGoldCreek,butcontributes40%oftheaverageannualflowatGoldCreek(47%oftheflowatWatana).Intermsofyield,theareaupstreamoftheDenaliandMaclarengagescontributes3.1ft3/sfmi2(0.2~m3/s/km2),andtheareadownstreamtoGoldCreekcontributes1.2ft3/s/mi(0.09m/s/km).Intherecorddroughtyearof1969,theproportionofflowatGoldCreekcontributedfromupstreamoftheDenaliandMaclarengagesincreasedto53.4%.Theapplicantchosetodismissthislow-flowyearasanextremelyrareoccurrencebyadjustingthemeanmonthlyflowsforWY1969upward(seeTableH.2-3andExhibitE,p.E-2-57).ThereissomeevidencefromtheEastForkGlacierthatglacierwastinghasbeenamajorcontributortotherunoffatGoldCreeksince1949(R&MandHarrison1981,1982).However,themagnitudeoftherunofffromglacierwastinghasnotbeenwelldocumentedandissubjecttoerror[anerrorof37%mayexistintheestimateof163ft(50m)ofsurfacealtitudelossattheEastForkGlacier].ExtrapolationoftheresultsfromEastForkGlaciertotheother275mi2(712km2)(or95%)oftheglaciersinthebasinisspeculative.Ratesofwastingvarynaturallyamongsites,andallglaciersundergonaturalcyclesofwasting(SugdenandJohn1976).Eventhoughthereisevidencethattheglaciershavebeenwastingsince1949,thereislittledataavailabletodeterminewhattheimpactofwastinghasbeenontherecordedflowatGoldCloeekorwhatwilloccurinthefuture.Largeglaciers,suchasthoseintheSusit~aBasin,takedecadestoattainequilibriumafterachangeinclimate.TheyalsoH-21peakequaltothemeanannualdailyfloodpeak.Inaddition,thesummerdailyfloodpeakof76,000ft3/s(2,152m3/s)isthesecondlargestfloodpeakatGoldCreekonrecord.Recurrenceintervalsforhighflowspersistingfor7consecutivedaysareshowninFigureH.2-2.ThemaximumrecordedinstantaneousfloodpeaksforDenali,Cantwell,andMaclaren,recordedbytheUSGS,arepresentedinTableH.2-5.Probable-maximum-flood(PMF)studieswereconductedforboththeWatanaandDevilCanyondamsitesforuseinthedesignofprojectspillwaysandrelatedfacilities(ExhibitE,Chapter2).ThePMFsweredeterminedbyusingtheSSARRwatershedmodeldevelopedbythePortlandDistrict,U.S.ArmyCorpsofEngineersandarebasedonSusitnaBasinclimaticdataandhydrology.Theprobablemaximumprecipitationwasderivedfromamaximizationstudyofhistoricalstorms.ThestudiesindicatethatthePMFpeakattheWatanadamsiteis326,000ft3/s(9,232m3/s).Theflow-durationcurvesbasedonpreprojectmeandailyflowsareshowninFigureH.2-3.Inthemajorityofcases,thethree-parameterlognormaldistributionprovidesthebestfittothedata(R&MandHarrison1981).Theshapeofthemonthlyandannualflowdurationcurvesissimilarforeachofthestationswithinthebasinandisindicativeofflowfromnorthernglacialrivers(ExhibitE,Chapter2).Streamflowislowinthewintermonths,withlittlevariationinflowandnounusualpeaks.Groundwatercontributionsaretheprimarysourceofthesmallbutrelativelyconstantwinterflows.FlowbeginstoincreaseslightlyinAprilasbreakupapproaches.PeakflowsinMayareanorderofmagnitudegreaterthaninApril.FlowinMayalsoshowsthegreatestvariationforanymonth,aslowflowsmaycontinueintoMaybeforethehighsnow-melt/breakupflowsoccur.Junehasthehighestpeaksandthehighestmeaianflowforthemiddleandupperbasinstations.ThemonthsofJulyandAugusthaverelativelyflatflow-durationcurves.Thissituationisindicativeofriverswithstrongbaseflowcharacteristics,asisthecaseontheSusitnawithitscontributionsfromsnowandglacialmeltduringthesummer.MorevariabilityofflowisevidentinSeptemberandOctoberascoolerweatherbecomesmoreprevalentaccompaniedbyadecreaseinglacialmeltandhencedischarge.Fromtneflow-durationcurveforGoldCreek(FigureH.2-3),itcanbeseenthatflowsatGoldCreekarelessthan20,000ft3/s(566m3/s)fromOctoberthroughApril.AsaresultofthespringbreakupinMay,flowsof20,000ft3/sareexceeded3~%ofthetime.DuringJuneandJuly,thepercentoftimeGoldCreekflowsexceed20,000ft/sincreasesto80%.Thispercentagedecreasesto65%inAugustandfurtherdecreasestoonlyabout15%inSeptember.Onanannualbasis,aflowof20,000ft3/sisexceeded20%ofthetime.The7-daylow-flowvaluesdeterminedforselectedmonthsatGoldCreekareshowninFigureH.2-4mayexhibitssubstantialvariability.BothlowwinterflowsandhighbreakupflowsusuallyoccurduringMay,andthussignificantchangesoccurfromyeartoyear.JuneexhibitsmorevariabilitythanJuly.FlowvariabilityincreasesagainintheAugustthroughOctoberperiod.HeavyrainstormsoftenoccurinAugust,with28%oftheannualfloodsoccurringinthismonth.Flowvariabilityinthewintermonthsisreducedconsiderably,reflectingthelowbaseflow.GlacialEffectsTheglaciatedportionsoftheSusitnaRiverBasinaboveGoldCreekplayasignificantroleinthehydrologyofthearea.LocatedonthesouthernslopesoftheAlaskaRange,theglaciatedregionsreceivethegreatestamountofsnowandrainfallinthebasin.Duringthesummermonths,theseregi~nscontr~butesignificantamountsofsnowandglacialmelt.Theglacierscoverabout290mi(750km)andactasreservoirsthatproducemostofthewaterinthebasinaboveGoldCreekduringdroughtperiods.ThedrainageareaupstreamoftheDenaliandMaclarengagescomprises20%ofthebasinaboveGoldCreek,butcontributes40%oftheaverageannualflowatGoldCreek(47%oftheflowatWatana).Intermsofyield,theareaupstreamoftheDenaliandMaclarengagescontributes3.1ft3/sfmi2(0.2~m3/s/km2),andtheareadownstreamtoGoldCreekcontributes1.2ft3/s/mi(0.09m/s/km).Intherecorddroughtyearof1969,theproportionofflowatGoldCreekcontributedfromupstreamoftheDenaliandMaclarengagesincreasedto53.4%.Theapplicantchosetodismissthislow-flowyearasanextremelyrareoccurrencebyadjustingthemeanmonthlyflowsforWY1969upward(seeTableH.2-3andExhibitE,p.E-2-57).ThereissomeevidencefromtheEastForkGlacierthatglacierwastinghasbeenamajorcontributortotherunoffatGoldCreeksince1949(R&MandHarrison1981,1982).However,themagnitudeoftherunofffromglacierwastinghasnotbeenwelldocumentedandissubjecttoerror[anerrorof37%mayexistintheestimateof163ft(50m)ofsurfacealtitudelossattheEastForkGlacier].ExtrapolationoftheresultsfromEastForkGlaciertotheother275mi2(712km2)(or95%)oftheglaciersinthebasinisspeculative.Ratesofwastingvarynaturallyamongsites,andallglaciersundergonaturalcyclesofwasting(SugdenandJohn1976).Eventhoughthereisevidencethattheglaciershavebeenwastingsince1949,thereislittledataavailabletodeterminewhattheimpactofwastinghasbeenontherecordedflowatGoldCloeekorwhatwilloccurinthefuture.Largeglaciers,suchasthoseintheSusit~aBasin,takedecadestoattainequilibriumafterachangeinclimate.Theyalso NOTE:PERIODOFRECORDWY1950-WY1981.H-221.051.125102050RECURRENCEINTERVAL(years)0.2L-_L.----ll.-...L-_--'-_...L..--l0.60.80.4100~~~~------"'-----.---r---.----,80210204060o6oS2~4cr::<lIU~oFigureH.2-2.Recurrenceintervalsfor7-dayhighflowsatGoldCreekduringopen-watermonths(May-August)andaice-covered,low-flowmonth(March).NOTE:PERIODOFRECORDWY1950-WY1981.H-221.051.125102050RECURRENCEINTERVAL(years)0.2L-_L.----ll.-...L-_--'-_...L..--l0.60.80.4100~~~~------"'-----.---r---.----,80210204060o6oS2~4cr::<lIU~oFigureH.2-2.Recurrenceintervalsfor7-dayhighflowsatGoldCreekduringopen-watermonths(May-August)andaice-covered,low-flowmonth(March). Table H.2-5.Maximum Flows of Record at Selected USGS Gaging Stations in the Susitna River Basin -- Denali Cantwell Gold Creek Maclaren Date Flow (ft3/s)Date Flow (ft 3/s)Date Flow (ft 3/s)Date Flow (ft 3/s) 8/10/71 38,200 8/10/71 55,000t l 6/7/64 90,700 8/11/71 9,2608/14-15/67 28,200 6/8/64 51,200 8/10/71 87,400 9/13/60 8,9207/28/80 24,300 6/15/623 46,800 6/17/72 82,600 8/14/67 7,4608/4/76 22,100 6/17/72 44,700 6/15/62 80,600 7/18/63 7,3008/9-10/81 22,000t3 8/14/67 38,800 8/15/67 80,200 6/16/72 7,070 ::c I32,000t4 N7/12/75 21,700 7/18/63 6/6/66 63,600 6/14/62 6,540 w7/27/68 19,000 8/14/81 30,500t3 8/25/59 62,300 8/5/61 6,540 tlEstimated maximum daily flow based on discharge records at Denali and Gold Creek. t 2APproximate date. t 3Maximum daily flow from preliminary USGS data. t 4Maximum daily flow. Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.11. Table H.2-5.Maximum Flows of Record at Selected USGS Gaging Stations in the Susitna River Basin Denali Cantwell Gold Creek MaclarenDateFlow(ft 3/s)Date Flow (ft 3/s)Date Flow (ft 3/s)Date Flow (ft 3/s) 8/10/71 38,200 8/10/71 55,000t l 6/7/64 90,700 8/11/71 9,2608/14-15/67 28,200 6/8/64 51,200 8/10/71 87,400 9/13/60 8,9207/28/80 24,300 6/15/62 3 46,800 6/17/72 82,600 8/14/67 7,4608/4/76 22,100 6/17/72 44,700 6/15/62 80,600 7/18/63 7,3008/9-10/81 22,000t 3 8/14/67 38,800 8/15/67 80,200 6/16/72 7,070 ::c I32,000t4 N7/12/75 21,700 7/18/63 6/6/66 63,600 6/14/62 6,540 w7/27/68 19,000 8/14/81 30,500t3 8/25/59 62,300 8/5/61 6,540 tlEstimated maximum daily flow based on discharge records at Denali and Gold Creek. t 2APproximate date. t 3Maximum daily flow from preliminary USGS data. t 4Maximum daily flow. Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.11. H-24FigureH.2-3.Pre-projectflowdurationcurvesfortheGoldCreekandSunshinegagingstationsbasedonmeandailyflows.Source:ExhibitE,FigureE.2.39.10050OCTOBERo501000LEGEND:----SUSITNARIVER--GOLDCREEKNOTES:1.FLOWDURATIONCURVESBASEDONMEANDAILYFLOWS.2.PERIODSOFRECORD:SUSITNARIVER:OCTOBER1974-SEPTEMBER1981GOLDCREEK:AUGUST1949-SEPTEMBER1981103L....J......L-L.....I--'-'-'-...........-oo50100050100050100PERCENTOFTIMEDISCHARGEEQUALLEDOREXCEEDED~.;105wt90:«i5104E-----...:::~(f)(5~E105wt90:«i5104(f)(5H-24FigureH.2-3.Pre-projectflowdurationcurvesfortheGoldCreekandSunshinegagingstationsbasedonmeandailyflows.Source:ExhibitE,FigureE.2.39.10050OCTOBERo501000LEGEND:----SUSITNARIVER--GOLDCREEKNOTES:1.FLOWDURATIONCURVESBASEDONMEANDAILYFLOWS.2.PERIODSOFRECORD:SUSITNARIVER:OCTOBER1974-SEPTEMBER1981GOLDCREEK:AUGUST1949-SEPTEMBER1981103L....J......L-L.....I--'-'-'-...........-oo50100050100050100PERCENTOFTIMEDISCHARGEEQUALLEDOREXCEEDED~.;105wt90:«i5104E-----...:::~(f)(5~E105wt90:«i5104(f)(5 H-254020108-;-6;;,.--0.80.60.40.2L_L-L-L---L_---L_L----l1.051.125102050RECURRENCEINTERVAL(years)NOTE:PERIODOF RECORDWY1950-WY1981.FigureH.2-4.Recurrenceintervalsfor7-daylowflowsatGoldCreekduringopen-watermonths(May-August)andaice-covered,low-flowmonth(March).Source:ExhibitE,FiguresE.2.55,E.2.57,andE.2.59.H-254020108-;-6;;,.--0.80.60.40.2L_L-L-L---L_---L_L---J1.051.125102050RECURRENCEINTERVAL(years)NOTE:PERIODOF RECORDWY1950-WY1981.FigureH.2-4.Recurrenceintervalsfor7-daylowflowsatGoldCreekduringopen-watermonths(May-August)andaice-covered,low-flowmonth(March).Source:ExhibitE,FiguresE.2.55,E.2.57,andE.2.59. H-26undergoshorter-termfluctuationsontheorderof30to50yea~s.TheSusitna~asingl~ciersmayhavereachedtheirmostrecentmaximumextentduringtheLlt~leI~eAge,.WhlChpers:steduntiltheearly1800sandmaystillberespondingtothec~angelncllmates~ncethat~lme.IftheestimatedrateofglacierwastingofEastForkGlaclerwerea110appllegtoSusltnaandWestForkglaciers~almost36%oftherecordedstreamflow[990ftIs(28mIs}JatDenaliand22%[220ft~/s(6.2m3/s}JatMaclarenwouldhavebeenfromglaciermelt.Therefore,12.5%oftheannualflowatGoldCreekand15%oftheannualflowatWatanamightbeattributabletoglacierwasting.Iftheglaciersweretostopwastingdueto,perhaps,aclimatechange,therecouldbeimplicationsforhydrologicalchangesthroughoutthebasin.Ontneotherhand,thewastingoftheglacierscouldeasilycontinueoverthelifeoftheproject.H.2.2PostprojectFlowsThepostprojectflowregimeswereestimatedbytheapplicant,usingamultireservoirenergysimulationmodeldescribedinExhibitE,Chapter2.3,andExhibitB.Theproposedoperationalflowregimesarebasedontheapplicant'strade-offanalysisbetweennetbenefitsfromhydroelectricpowerproductionandfisheryimpacts.TheseproposedflowsincorporateminimumreleaserequirementsatGoldCreekof5,000ft3/s(142m3/s1fromOctoberthroughApril,6,000ft3/s(170m3s)fromMay1throughJuly31,12,000ft/s(340m3/s)fromAugust1throughSeptember15,and6,000ft3/sfortheremainderofSeptember.TheaveragemonthlyflowsattheGoldCreekandSunshinegagingstationsthatwouldbeproducedbythe32-yearhistoricalflowrecordarepresentedinTablesH.2-6, H.2-7,H.2-8andH.2-9.Comparisonsoftheflow-durationcurvesatGoldCreekandSunshineunderpreproject,Watana,andcombinedWatana-DevilCanyonoperationalflowsarepresentedinFigureH.2-5andH.2-6.Pre-andpostprojectrecurrenceintervalsforthemeanannualfloodatGoldCreekarepresentedinFigureH.2-7.H.3HABITATALTERATIONThemainstemflowregimeresultingfromtheproposedprojectwillcausechangesinphysicalhabitatalongtheriverbelowthedams.Thesechangeswereanalyzed,usingthepreprojectmonthlyflowregimesattheGoldCreekandSunshinegagingstations(TablesH.2-3andH.2-4)andthepostprojectmonthlyflowregimesdescribedbythea§Plicantundertheproposedoperatingschedule[CaseC,minimumAugustflow=12,000ftIs(340m3/s}J.ThepredictedpostprojectflowsatGoldCreekandSunshinestationsforWatanaaloneandWatana-DevilCanyonoperationsarepresentedinTablesH.2-6throughH.2-9.Changesintheavailabilityofside-sloughhabitatwereevaluatedthreeways.First,thefrequencyofoccurrenceofvarioushydraulicregimeswasexaminedunderpreprojectandpostprojectflowregimes.Thethreehydraulicregimesinsidesloughsweredefinedas(l)overtopping,(2)backwater,and(3)isolation(seeExhibitE,AppendixE.2.A).Second,thefrequencyofoccurrenceofaccessibilitylimitationsforspawningsalmonidswasexamined,basedonaccesscriteriaestablishedbytheADFG(1983).Third,thefrequencyofoccurrenceofchangesinthewettedsurfaceareawasevaluatedunderpostprojectflowregimesrelativetopreprojectflows.SloughHydraulicRegimesThreehydraulicregimesinsidesloughsalongtheSusitnaRiverhavebeendefined(ExhibitE,AppendixE.2.A).Thefirstconditionisovertopping,wherethemainstemstageisabovethegravelbermattheupperendofthesidesloughandthesloughisactingasatrueoverflowchannel.Underthisovertoppingregime,hydrauliccharacteristicsarecompletelydependentonmainstemdischarge.Sloughdischargeistypicallyontheorderofseveralhundredcubicfeetpersecond.Thesecondcqnditionisonewherebackwatereffectspredominate:themainstemstageisbelowtheelevationoftheupstreambermandabackwaterextendsupstreamfromthelowermonthoftheslough.Underthisbackwaterregime,themainstemstageatthelowerendoftheslougnactsasahydrauliccontrol.Hydraulicsloughcharacteristicsarelargelyindependentofmainstemdischarge,andsloughdischargedropsbyanorderofmagnitudeormore.Thethirdregimeisisolationofthesideslough,wherethemainstemstagedropsbelowthebedelevationofthelowermouthofthesidesloughandthebackwaterzonedisappears.Undertheisolationregime,sloughdischargeiscompletelydependentongroundwaterseepageandlocalrunoff,actingessentiallyasaminortributarytothemainstem.TheapplicantestablishedthresholdsofmainstemflowatGoldCreekatwhichthesehydraulicregimesoccurredinthreeselectedsidesloughsaboveTalkeetnaandonesidesloughbelowTalkeetna(TableH.3-1).Thesethresholdswerecomparedtotheflow-durationcurves(FiguresH.2-5andH.2-6)forpre-andpostprojectflowstoestimatethefrequencyofoccurrenceofmainstemflowswhichwouldproduceeachhydraulicregime.ForthethreesloughsaboveTalkeetna,anaveragethresholdwasused(TableH.3-1).Usingtheaveragesloughresponse,thisanalysisindicatesthatovertopping(RegimeI)wouldoccurveryrarelyaboveTalkeetnaafterWatanaDambeganoperating(TableH.3-2).Thebackwatercondition(RegimeII)wouldpersistonlYinJune,July,andAugust(12,2,and16%oftheH-26undergoshorter-termfluctuationsontheorderof30to50yea~s.TheSusitna~asingl~ciersmayhavereachedtheirmostrecentmaximumextentduringtheLlt~leI~eAge,.WhlChpers:steduntiltheearly1800sandmaystillberespondingtothec~angelncllmates~ncethat~lme.IftheestimatedrateofglacierwastingofEastForkGlaclerwerea110appllegtoSusltnaandWestForkglaciers~almost36%oftherecordedstreamflow[990ftIs(28mIs}JatDenaliand22%[220ft~/s(6.2m3/s}JatMaclarenwouldhavebeenfromglaciermelt.Therefore,12.5%oftheannualflowatGoldCreekand15%oftheannualflowatWatanamightbeattributabletoglacierwasting.Iftheglaciersweretostopwastingdueto,perhaps,aclimatechange,therecouldbeimplicationsforhydrologicalchangesthroughoutthebasin.Ontneotherhand,thewastingoftheglacierscouldeasilycontinueoverthelifeoftheproject.H.2.2PostprojectFlowsThepostprojectflowregimeswereestimatedbytheapplicant,usingamultireservoirenergysimulationmodeldescribedinExhibitE,Chapter2.3,andExhibitB.Theproposedoperationalflowregimesarebasedontheapplicant'strade-offanalysisbetweennetbenefitsfromhydroelectricpowerproductionandfisheryimpacts.TheseproposedflowsincorporateminimumreleaserequirementsatGoldCreekof5,000ft3/s(142m3/s1fromOctoberthroughApril,6,000ft3/s(170m3s)fromMay1throughJuly31,12,000ft/s(340m3/s)fromAugust1throughSeptember15,and6,000ft3/sfortheremainderofSeptember.TheaveragemonthlyflowsattheGoldCreekandSunshinegagingstationsthatwouldbeproducedbythe32-yearhistoricalflowrecordarepresentedinTablesH.2-6, H.2-7,H.2-8andH.2-9.Comparisonsoftheflow-durationcurvesatGoldCreekandSunshineunderpreproject,Watana,andcombinedWatana-DevilCanyonoperationalflowsarepresentedinFigureH.2-5andH.2-6.Pre-andpostprojectrecurrenceintervalsforthemeanannualfloodatGoldCreekarepresentedinFigureH.2-7.H.3HABITATALTERATIONThemainstemflowregimeresultingfromtheproposedprojectwillcausechangesinphysicalhabitatalongtheriverbelowthedams.Thesechangeswereanalyzed,usingthepreprojectmonthlyflowregimesattheGoldCreekandSunshinegagingstations(TablesH.2-3andH.2-4)andthepostprojectmonthlyflowregimesdescribedbythea§Plicantundertheproposedoperatingschedule[CaseC,minimumAugustflow=12,000ftIs(340m3/s}J.ThepredictedpostprojectflowsatGoldCreekandSunshinestationsforWatanaaloneandWatana-DevilCanyonoperationsarepresentedinTablesH.2-6throughH.2-9.Changesintheavailabilityofside-sloughhabitatwereevaluatedthreeways.First,thefrequencyofoccurrenceofvarioushydraulicregimeswasexaminedunderpreprojectandpostprojectflowregimes.Thethreehydraulicregimesinsidesloughsweredefinedas(l)overtopping,(2)backwater,and(3)isolation(seeExhibitE,AppendixE.2.A).Second,thefrequencyofoccurrenceofaccessibilitylimitationsforspawningsalmonidswasexamined,basedonaccesscriteriaestablishedbytheADFG(1983).Third,thefrequencyofoccurrenceofchangesinthewettedsurfaceareawasevaluatedunderpostprojectflowregimesrelativetopreprojectflows.SloughHydraulicRegimesThreehydraulicregimesinsidesloughsalongtheSusitnaRiverhavebeendefined(ExhibitE,AppendixE.2.A).Thefirstconditionisovertopping,wherethemainstemstageisabovethegravelbermattheupperendofthesidesloughandthesloughisactingasatrueoverflowchannel.Underthisovertoppingregime,hydrauliccharacteristicsarecompletelydependentonmainstemdischarge.Sloughdischargeistypicallyontheorderofseveralhundredcubicfeetpersecond.Thesecondcqnditionisonewherebackwatereffectspredominate:themainstemstageisbelowtheelevationoftheupstreambermandabackwaterextendsupstreamfromthelowermonthoftheslough.Underthisbackwaterregime,themainstemstageatthelowerendoftheslougnactsasahydrauliccontrol.Hydraulicsloughcharacteristicsarelargelyindependentofmainstemdischarge,andsloughdischargedropsbyanorderofmagnitudeormore.Thethirdregimeisisolationofthesideslough,wherethemainstemstagedropsbelowthebedelevationofthelowermouthofthesidesloughandthebackwaterzonedisappears.Undertheisolationregime,sloughdischargeiscompletelydependentongroundwaterseepageandlocalrunoff,actingessentiallyasaminortributarytothemainstem.TheapplicantestablishedthresholdsofmainstemflowatGoldCreekatwhichthesehydraulicregimesoccurredinthreeselectedsidesloughsaboveTalkeetnaandonesidesloughbelowTalkeetna(TableH.3-1).Thesethresholdswerecomparedtotheflow-durationcurves(FiguresH.2-5andH.2-6)forpre-andpostprojectflowstoestimatethefrequencyofoccurrenceofmainstemflowswhichwouldproduceeachhydraulicregime.ForthethreesloughsaboveTalkeetna,anaveragethresholdwasused(TableH.3-1).Usingtheaveragesloughresponse,thisanalysisindicatesthatovertopping(RegimeI)wouldoccurveryrarelyaboveTalkeetnaafterWatanaDambeganoperating(TableH.3-2).Thebackwatercondition(RegimeII)wouldpersistonlYinJune,July,andAugust(12,2,and16%ofthe Table H.2-6.Predicted Postproject Monthly Flows (ft3/s)at Gold Creek under Watana Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Annual 1 7280 10216 11555 9918 9105 8238 7574 8487 8022 8024 12000 9282 9145.8 2 6390 6833 7910 7342 6437 6589 5989 10314 7108 7562 12000 9300 7831.3 3 8061 10738 12016 10491 9317 8392 7624 6529 11599 9076 12000 9300 9595.1 4 10186 11491 11816 9991 9137 8332 8319 15608 10810 7406 12000 9300 10380.5 5 7076 7092 11616 10191 9317 8292 7939 13953 10736 7967 12000 9300 9635.0 6 7195 7955 12161 10685 9717 8612 7904 7860 10153 10622 16276 9300 9882.5 7 8469 9894 11416 9871 9287 8452 7654 14207 15257 14078 15432 13411 11468.8 8 9377 11044 12258 10591 9817 8712 7904 10575 12008 8110 12000 12213 10384.1 9 11783 11948 13380 10856 9624 8660 8237 9746 8566 7883 12000 9121 10162.0 10 6875 6933 8170 10339 9624 8492 7954 12818 9829 9288 16209 11843 9874.3 11 10129 10844 12316 10736 9769 8709 8004 12318 7167 8287 12000 9300 9978.8 12 8227 10994 12810 11343 10071 9322 9354 13838 11869 9478 12000 9300 10726.1 13 7329 10694 12216 10791 9817 8912 8404 9299 24152 9986 14667 10430 11381.9 14 10294 10794 12116 10491 9817 8512 7534 15342 10296 15149 15147 9300 11263.3 15 7778 10244 11610 9939 9283 8225 7449 6061 26092 7887 12000 9300 10468.3 16 7291 6967 7679 9658 9177 8412 8064 9736 9470 9772 12000 13506 9309.7 :r:: f171077610092 11747 10291 9617 8812 8479 7810 13487 8262 12000 9300 10056.4 N "-.I1866166903798510391971787127871120671163610363227041195110593.9 19 8471 10347 12171 10872 10217 9412 8614 12740 13602 10043 12000 9300 10654.4 20 6582 6882 7830 7839 9239 8345 7726 7169 7866 6852 12000 9300 8128.7 21 6629 7004 8013 7518 6586 6771 5920 7272 9214 8997 12000 9300 7947.1 22 7491 7701 8482 7681 6678 6848 6091 6390 10484 7762 13149 9300 8181.2 23 8728 11087 12626 11130 10345 9335 8414 18135 16602 7692 12000 9300 11289.7 24 6222 6865 11581 10091 9517 8512 7731 6207 8914 6484 12000 9300 8615.7 25 6457 6742 7725 7179 6725 8236 7696 12773 7949 7483 12000 9300 8370.1 26 6551 7008 8138 7574 6719 6896 6121 9025 13491 11081 12000 9300 8671.0 27 9816 9987 11197 9865 9267 8412 8077 9568 9350 6513 12000 8051 9347.6 28 6728 7351 8393 7616 6647 7982 8384 9665 19061 7908 12000 9300 9255.0 29 7469 10068 12705 10920 9985 9117 8406 8669 6617 7243 12000 9300 9378.3 30 7015 7274 8119 7476 6537 6577 5811 9811 6908 11719 12000 9300 8235.0 31 6842 11972 12532 10639 9783 8912 8374 8888 11113 15152 12030 9300 10469.9 32 10320 11980 11890 10344 9552 8626 8071 10118 6000 9792 26494 10461 11172.4 Max 11783 11980 13380 11343 10345 9412 9354 18135 26092 15152 26494 13506 11468.8 Min 6222 6742 7679 7179 6437 6577 5811 6061 6000 6484 12000 8051 7831.3 Mean 8014 9186 10693 9708 8951 8324 7740 10405 11420 9185 13378 9840 9745.4 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.44. Table H.2-6.Predicted Postproject Monthly Flows (ft3/s)at Gold Creek under Watana Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Annual 1 7280 10216 11555 9918 9105 8238 7574 8487 8022 8024 12000 9282 9145.8 2 6390 6833 7910 7342 6437 6589 5989 10314 7108 7562 12000 9300 7831.3 3 8061 10738 12016 10491 9317 8392 7624 6529 11599 9076 12000 9300 9595.1 4 10186 11491 11816 9991 9137 8332 8319 15608 10810 7406 12000 9300 10380.5 5 7076 7092 11616 10191 9317 8292 7939 13953 10736 7967 12000 9300 9635.0 6 7195 7955 12161 10685 9717 8612 7904 7860 10153 10622 16276 9300 9882.5 7 8469 9894 11416 9871 9287 8452 7654 14207 15257 14078 15432 13411 11468.8 8 9377 11044 12258 10591 9817 8712 7904 10575 12008 8110 12000 12213 10384.1 9 11783 11948 13380 10856 9624 8660 8237 9746 8566 7883 12000 9121 10162.0 10 6875 6933 8170 10339 9624 8492 7954 12818 9829 9288 16209 11843 9874.3 11 10129 10844 12316 10736 9769 8709 8004 12318 7167 8287 12000 9300 9978.8 12 8227 10994 12810 11343 10071 9322 9354 13838 11869 9478 12000 9300 10726.1 13 7329 10694 12216 10791 9817 8912 8404 9299 24152 9986 14667 10430 11381.9 14 10294 10794 12116 10491 9817 8512 7534 15342 10296 15149 15147 9300 11263.3 15 7778 10244 11610 9939 9283 8225 7449 6061 26092 7887 12000 9300 10468.3 16 7291 6967 7679 9658 9177 8412 8064 9736 9470 9772 12000 13506 9309.7 :r:: f171077610092 11747 10291 9617 8812 8479 7810 13487 8262 12000 9300 10056.4 N 18 6616 6903 7985 10391 9717 8712 7871 12067 11636 10363 22704 11951 10593.9 "-.I 19 8471 10347 12171 10872 10217 9412 8614 12740 13602 10043 12000 9300 10654.4 20 6582 6882 7830 7839 9239 8345 7726 7169 7866 6852 12000 9300 8128.7 21 6629 7004 8013 7518 6586 6771 5920 7272 9214 8997 12000 9300 7947.1 22 7491 7701 8482 7681 6678 6848 6091 6390 10484 7762 13149 9300 8181.2 23 8728 11087 12626 11130 10345 9335 8414 18135 16602 7692 12000 9300 11289.7 24 6222 6865 11581 10091 9517 8512 7731 6207 8914 6484 12000 9300 8615.7 25 6457 6742 7725 7179 6725 8236 7696 12773 7949 7483 12000 9300 8370.1 26 6551 7008 8138 7574 6719 6896 6121 9025 13491 11081 12000 9300 8671.0 27 9816 9987 11197 9865 9267 8412 8077 9568 9350 6513 12000 8051 9347.6 28 6728 7351 8393 7616 6647 7982 8384 9665 19061 7908 12000 9300 9255.0 29 7469 10068 12705 10920 9985 9117 8406 8669 6617 7243 12000 9300 9378.3 30 7015 7274 8119 7476 6537 6577 5811 9811 6908 11719 12000 9300 8235.0 31 6842 11972 12532 10639 9783 8912 8374 8888 11113 15152 12030 9300 10469.9 32 10320 11980 11890 10344 9552 8626 8071 10118 6000 9792 26494 10461 11172.4 Max 11783 11980 13380 11343 10345 9412 9354 18135 26092 15152 26494 13506 11468.8 Min 6222 6742 7679 7179 6437 6577 5811 6061 6000 6484 12000 8051 7831.3 Mean 8014 9186 10693 9708 8951 8324 7740 10405 11420 9185 13378 9840 9745.4 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.44. Table H.2-7.Predicted Postproject Monthly Flows (ft 3/s)at Sunshine Under Watana Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annual 1 14948 13272 13727 11639 10593 9545 9015 19395 34035 44603 46969 28715 21460.9 2 14768 10245 10614 9312 8052 7993 7935 38420 45190 54466 50686 39129 24861.4 3 16203 13696 13898 12361 10828 9794 9061 12368 47967 47623 44443 26877 22160.5 4 19378 15193 14196 11709 10660 9829 10996 46640 47565 41437 41344 27767 24834.4 5 14699 10084 14093 12558 11206 9935 9908 29268 40291 40993 43601 24756 21875.2 6 14013 11535 14429 12818 11506 10089 9362 20299 49979 53956 68218 30395 25667.8 7 14529 12361 13277 11503 10603 9721 8948 29704 55858 63556 59936 39576 27583.9 8 18823 15023 15023 12897 11788 10356 9611 30965 61001 47102 44703 40534 26550.7 9 21970 17026 16255 12958 11313 10155 10103 24605 43618 44853 46362 21669 23509.9 10 13642 10114 10249 12278 11376 9792 9599 26288 50795 51809 56977 31838 24660.1 11 18702 14409 14939 12950 11518 10187 9632 31340 30948 43531 43725 31876 22917.7 12 17429 14103 15620 13630 11795 10992 11813 28916 43305 48548 50516 32001 24992.0 13 15992 14651 14936 13113 11659 10487 10285 21229 68419 51892 52298 33251 26583.3 14 17527 14046 14806 12965 11938 9911 8729 31557 40925 58968 44415 26162 24451.1 15 19884 13901 13649 11688 10764 9525 9085 10399 86585 43773 41934 22996 24533.6 16 16473 11640 11004 12071 11279 10330 10139 21343 42238 46974 47255 47859 24112.2 :I: I1721779133151408112295 11326 10387 10302 14644 50106 43645 52177 27706 23559.4 N 18 14004 9598 10341 12589 11611 10305 9343 29499 48288 60688 72831 32460 26941.5 00 19 14277 13407 14679 13072 12303 11410 11063 33521 58822 53358 41560 21369 24992.9 20 12834 9457 9728 9442 10048 9534 9146 18623 36692 37324 38648 24356 18879.2 21 12921 9767 9995 9294 8266 8377 7990 21579 38186 47108 46946 27370 20749.6 22 14467 11761 11122 9564 8156 8249 7649 13297 53762 48599 55758 27262 22559.2 23 17194 14739 15038 13148 12118 10847 9914 32425 49028 47214 43964 31056 24811.2 24 14984 10630 14146 12203 11301 10158 9525 16187 41047 39945 42795 25464 20765.2 25 14008 9918 10215 9187 8467 9732 9620 28039 33792 39950 39002 26164 19934.2 26 15114 10246 10312 9604 8238 8306 7688 23055 54017 59053 45588 28557 23418.8 27 17642 12232 12850 11398 10672 9793 9998 19823 41336 43079 44355 19672 21159.0 28 13474 10589 11275 10018 8669 9653 10241 24277 68864 47232 47917 29379 24367.6 29 17297 13673 15429 13104 11544 10514 10246 19426 35611 44153 37728 23435 21094.0 30 13331 10387 10746 9753 8457 8340 8065 29817 42067 54604 40437 25320 21889.9 31 17219 17180 15305 13109 12016 11031 11331 23735 47117 66765 41694 23855 25138.4 32 19175 16189 14921 13324 12374 10924 10996 32962 38747 63392 72896 29750 28143.3 Max 21970 17180 16255 13630 12374 11410 11813 46640 86585 66765 72896 47859 28143.3 r~in 12834 9457 9728 9187 8052 7993 7649 10399 30948 37324 37728 19672 18879.2 Mean 16209 12637 13153 11798 10701 9881 9604 25114 47694 49381 48365 29018 23723.7 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E.2.46. Table H.2-7.Predicted Postproject Monthly Flows (ft 3/s)at Sunshine Under Watana Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annual 1 14948 13272 13727 11639 10593 9545 9015 19395 34035 44603 46969 28715 21460.9 2 14768 10245 10614 9312 8052 7993 7935 38420 45190 54466 50686 39129 24861.4 3 16203 13696 13898 12361 10828 9794 9061 12368 47967 47623 44443 26877 22160.5 4 19378 15193 14196 11709 10660 9829 10996 46640 47565 41437 41344 27767 24834.4 5 14699 10084 14093 12558 11206 9935 9908 29268 40291 40993 43601 24756 21875.2 6 14013 11535 14429 12818 11506 10089 9362 20299 49979 53956 68218 30395 25667.8 7 14529 12361 13277 11503 10603 9721 8948 29704 55858 63556 59936 39576 27583.9 8 18823 15023 15023 12897 11788 10356 9611 30965 61001 47102 44703 40534 26550.7 9 21970 17026 16255 12958 11313 10155 10103 24605 43618 44853 46362 21669 23509.9 10 13642 10114 10249 12278 11376 9792 9599 26288 50795 51809 56977 31838 24660.1 11 18702 14409 14939 12950 11518 10187 9632 31340 30948 43531 43725 31876 22917.7 12 17429 14103 15620 13630 11795 10992 11813 28916 43305 48548 50516 32001 24992.0 13 15992 14651 14936 13113 11659 10487 10285 21229 68419 51892 52298 33251 26583.3 14 17527 14046 14806 12965 11938 9911 8729 31557 40925 58968 44415 26162 24451.1 15 19884 13901 13649 11688 10764 9525 9085 10399 86585 43773 41934 22996 24533.6 16 16473 11640 11004 12071 11279 10330 10139 21343 42238 46974 47255 47859 24112.2 :I: I1721779133151408112295 11326 10387 10302 14644 50106 43645 52177 27706 23559.4 N 18 14004 9598 10341 12589 11611 10305 9343 29499 48288 60688 72831 32460 26941.5 00 19 14277 13407 14679 13072 12303 11410 11063 33521 58822 53358 41560 21369 24992.9 20 12834 9457 9728 9442 10048 9534 9146 18623 36692 37324 38648 24356 18879.2 21 12921 9767 9995 9294 8266 8377 7990 21579 38186 47108 46946 27370 20749.6 22 14467 11761 11122 9564 8156 8249 7649 13297 53762 48599 55758 27262 22559.2 23 17194 14739 15038 13148 12118 10847 9914 32425 49028 47214 43964 31056 24811.2 24 14984 10630 14146 12203 11301 10158 9525 16187 41047 39945 42795 25464 20765.2 25 14008 9918 10215 9187 8467 9732 9620 28039 33792 39950 39002 26164 19934.2 26 15114 10246 10312 9604 8238 8306 7688 23055 54017 59053 45588 28557 23418.8 27 17642 12232 12850 11398 10672 9793 9998 19823 41336 43079 44355 19672 21159.0 28 13474 10589 11275 10018 8669 9653 10241 24277 68864 47232 47917 29379 24367.6 29 17297 13673 15429 13104 11544 10514 10246 19426 35611 44153 37728 23435 21094.0 30 13331 10387 10746 9753 8457 8340 8065 29817 42067 54604 40437 25320 21889.9 31 17219 17180 15305 13109 12016 11031 11331 23735 47117 66765 41694 23855 25138.4 32 19175 16189 14921 13324 12374 10924 10996 32962 38747 63392 72896 29750 28143.3 Max 21970 17180 16255 13630 12374 11410 11813 46640 86585 66765 72896 47859 28143.3 r~in 12834 9457 9728 9187 8052 7993 7649 10399 30948 37324 37728 19672 18879.2 Mean 16209 12637 13153 11798 10701 9881 9604 25114 47694 49381 48365 29018 23723.7 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E.2.46. Table H.2-8.Predicted Postproject Monthly Flows (ft 3/s)at Gold Creek Under Combined Watana-Devi1 Canyon Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annua 1 1 7179 10934 12578 11650 10939 8865 7473 7324 7179 7206 12000 9300 9380.2 2 6749 7141 8135 7498 6524 6632 7139 8785 6555 6708 12000 9300 7776.4 3 6839 10431 12669 11727 11181 9860 7523 6195 9795 7902 12000 9300 9609.5 4 7307 11650 12668 11690 11212 9983 8218 11255 12070 6776 12000 9300 10337.3 5 7252 7248 11896 11316 10980 8919 7838 11870 9085 7156 12000 9300 9573.3 6 7287 7392 12739 11782 11311 10536 7803 7151 10161 8894 12000 10444 9788.5 7 7933 11124 12572 11625 10950 9079 7553 11582 12282 11089 13620 18330 11473.3 8 8788 11674 12683 11722 11278 10459 8834 8556 11415 7132 12000 10173 10384.1 9 10983 11849 13134 11797 11208 10383 9465 9008 9227 6982 12000 9300 10443.8 10 7116 7230 8182 9993 11287 9119 7853 10728 8423 7949 12783 14603 9592.6 11 9540 11577 12750 11805 11280 10439 8856 10231 6577 7265 12000 9300 10137.1 12 7204 10747 12887 12046 11453 10604 9759 10900 12635 8837 12000 9300 10692.4 13 7074 10063 12681 11701 11234 10433 9195 7354 12998 9032 17532 15890 11257.3 14 9705 11333 12581 11697 11282 10356 8333 10911 11714 11390 12000 11551 11072.9 15 9431 11474 12599 11639 11191 8852 7348 6000 13305 9366 12000 9300 10199.1 16 7306 9196 12487 11601 10840 9039 7963 7766 9244 9185 12000 10645 9769.4 :::I: I1710187113221268911739 11293 9948 8378 7117 12900 7381 12000 9300 10345.3 N 18 6931 7213 8172 9698 11380 9339 7770 10069 11354 9841 15192 16870 10305.0 \D 19 7882 11423 12737 11752 11301 10510 9519 10652 12076 10472 12000 9300 10800.3 20 6890 7179 8091 8778 10902 8972 7625 6687 7094 6484 ,12000 9300 8318.1 21 6921 7212 8196 7607 6614 6743 6578 6746 7960 7842 12000 9300 7820.4 22 7515 7725 8500 7697 6656 6770 5950 6562 8695 6750 12000 10053 7914.2 23 8829 11485 12762 11868 11406 10581 9559 12380 12820 9462 12000 9300 11037.3 24 6453 11030 12542 11620 11214 9529 7630 6021 8279 6484 12000 9300 9329.5 25 6820 7104 8041 7424 6457 8102 7595 10612 7121 6807 12000 9300 8132.5 26 6850 7200 8269 7635 6698 6818 5990 9487 11922 10438 12000 9300 8565.2 27 8528 11217 12532 11440 10930 9039 7976 7890 8011 6484 12000 9300 9606.7 28 7001 7516 8491 7708 6687 9215 8283 8184 12592 9629 12000 9300 8895.9 29 7357 11299 12808 11811 11340 10516 9494 6986 6213 6662 12000 9300 9641.2 30 7191 7439 8272 7582 6587 6618 7366 .8522 8244 10003 12000 9300 8275.9 31 7096 9129 12650 11690 11226 10431 9358 6922 12307 11846 12000 9300 10325.4 32 8334 11633 12677 11760 11268 10448 8994 8150 6000 8941 21146 13171 11053.7 Max 10983 11849 13134 12046 11453 10604 9759 12380 13305 11846 21146 18330 11473.3 Min 6453 7104 8041 7424 6457 6618 5950 6000 6000 6484 12000 9300 7776.4 Mean 7765 9631 11271 10597 10191 9286 8100 8706 9883 8387 12634 10510 9745.5 Conversion:To convert from cubic feet to cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E.2.54. Table H.2-8.Predicted Postproject Monthly Flows (ft 3/s)at Gold Creek Under Combined Watana-Devi1 Canyon Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annua 1 1 7179 10934 12578 11650 10939 8865 7473 7324 7179 7206 12000 9300 9380.2 2 6749 7141 8135 7498 6524 6632 7139 8785 6555 6708 12000 9300 7776.4 3 6839 10431 12669 11727 11181 9860 7523 6195 9795 7902 12000 9300 9609.5 4 7307 11650 12668 11690 11212 9983 8218 11255 12070 6776 12000 9300 10337.3 5 7252 7248 11896 11316 10980 8919 7838 11870 9085 7156 12000 9300 9573.3 6 7287 7392 12739 11782 11311 10536 7803 7151 10161 8894 12000 10444 9788.5 7 7933 11124 12572 11625 10950 9079 7553 11582 12282 11089 13620 18330 11473.3 8 8788 11674 12683 11722 11278 10459 8834 8556 11415 7132 12000 10173 10384.1 9 10983 11849 13134 11797 11208 10383 9465 9008 9227 6982 12000 9300 1G443.8 10 7116 7230 8182 9993 11287 9119 7853 10728 8423 7949 12783 14603 9592.6 11 9540 11577 12750 11805 11280 10439 8856 10231 6577 7265 12000 9300 10137.1 12 7204 10747 12887 12046 11453 10604 9759 10900 12635 8837 12000 9300 10692.4 13 7074 10063 12681 11701 11234 10433 9195 7354 12998 9032 17532 15890 11257.3 14 9705 11333 12581 11697 11282 10356 8333 10911 11714 11390 12000 11551 11072.9 15 9431 11474 12599 11639 11191 8852 7348 6000 13305 9366 12000 9300 10199.1 16 7306 9196 12487 11601 10840 9039 7963 7766 9244 9185 12000 10645 9769.4 :::I: I1710187 11322 12689 11739 11293 9948 8378 7117 12900 7381 12000 9300 10345.3 N 18 6931 7213 8172 9698 11380 9339 7770 10069 11354 9841 15192 16870 10305.0 \D 19 7882 11423 12737 11752 11301 10510 9519 10652 12076 10472 12000 9300 10800.3 20 6890 7179 8091 8778 10902 8972 7625 6687 7094 6484 ,12000 9300 8318.1 21 6921 7212 8196 7607 6614 6743 6578 6746 7960 7842 12000 9300 7820.4 22 7515 7725 8500 7697 6656 6770 5950 6562 8695 6750 12000 10053 7914.2 23 8829 11485 12762 11868 11406 10581 9559 12380 12820 9462 12000 9300 11037.3 24 6453 11030 12542 11620 11214 9529 7630 6021 8279 6484 12000 9300 9329.5 25 6820 7104 8041 7424 6457 8102 7595 10612 7121 6807 12000 9300 8132.5 26 6850 7200 8269 7635 6698 6818 5990 9487 11922 10438 12000 9300 8565.2 27 8528 11217 12532 11440 10930 9039 7976 7890 8011 6484 12000 9300 9606.7 28 7001 7516 8491 7708 6687 9215 8283 8184 12592 9629 12000 9300 8895.9 29 7357 11299 12808 11811 11340 10516 9494 6986 6213 6662 12000 9300 9641.2 30 7191 7439 8272 7582 6587 6618 7366 .8522 8244 10003 12000 9300 8275.9 31 7096 9129 12650 11690 11226 10431 9358 6922 12307 11846 12000 9300 10325.4 32 8334 11633 12677 11760 11268 10448 8994 8150 6000 8941 21146 13171 11053.7 Max 10983 11849 13134 12046 11453 10604 9759 12380 13305 11846 21146 18330 11473.3 Min 6453 7104 8041 7424 6457 6618 5950 6000 6000 6484 12000 9300 7776.4 Mean 7765 9631 11271 10597 10191 9286 8100 8706 9883 8387 12634 10510 9745.5 Conversion:To convert from cubic feet to cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E.2.54. Table H.2-9.Predicted Postproject Monthly Flows (ft3/s)at Sunshine Under Combined Watana-Devi1 Canyon Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annual 1 14847 13990 14750 13371 12427 10172 8914 18232 33192 43785 46969 28733 21695.3 2 15127 10553 10839 9468 8139 8036 9085 36891 44637 53612 50686 39129 24806.6 3 14981 13389 14551 23597 12692 11262 8960 12034 46163 46449 44443 26877 22174.9 4 16499 15352 15048 13408 12735 11480 10895 42287 48825 40807 41344 27767 24791.3 5 14875 10240 14373 13683 12869 10562 9807 27185 38640 40182 43601 24756 21813.5 6 14105 10972 15007 13915 13100 12013 9261 19590 49987 52228 63942 31539 25573.7 7 13993 13591 14433 13257 12266 10348 8847 27079 52883 60568 58124 44495 27588.4 8 18234 15653 15448 14028 13249 12103 10541 28946 60408 46124 44703 38494 26550.7 9 21170 16927 16009 13899 12897 11878 11331 23867 44279 43952 46362 21848 23791.6 10 13883 10411 '10261 11932 13039 10419 9498 24198 49389 50470 53551 34598 24378.4 11 18113 15142 15373 14019 13029 11917 10484 29253.30358 42509 43725 31876 23076.1 12 16406 13856 15697 14333 13177 12274 12218 25978 44071 47907 50516 32001 24958.3 13 15737 14020 15401 14023 13076 12008 11076 19284 57265 50938 55163 38711 26458.7 14 16938 14585 15271 14171 13403 11755 9528 27126 42343 55209 41268 28413 24260.8 15 21537 15131 14638 13388 12672 10152 8984 10338 73798 45252 41934 22996 24264.4 16 16488 13869 15812 14014 12942 10957 10038 19373 42012 46387 47255 44998 24571.8 :::I: I 17 21190 14545 15023 13743 13002 11523 .10201 13951 49519 42764 52177 27706 23848.3 w 01814319990810528 11896 13274 10932 9242 27501 48006 60166 65319 37379 26652.5 19 13688 14483 15245 13952 13387 12508 11968 31433 57296 53787 41560 21369 25138.8 20 13142 9754 9989 10381 11711 10161 9045 18141 35920 36956 38648 24356 19068.6 21 13213 9975 10178 9383 8294 8349 8648 21053 36932 45953 46946 27370 20622.9 22 14491 11785 11140 9580 8134 8171 7508 13469 51973 47587 54609 28015 22292.2 23 17295 15137 15174 13886 13179 12093 11059 26670 45246 48984 43964 31056 24558.8 24 15215 14795 15107 13732 12998 11175 9424 16001 40412 39945 42795 25464 21479.0 25 14371 10280 10531 9432 8199 9598 9519 25918 32964 39274 39002 26164 19696.6 26 15413 10438 10443 9665 8217 8228 7557 23517 52448 58410 45588 28557 23313.0 27 16354 13462 141a5 12973 12335 10420 9897 18145 39997 43050 44355 20921 21418.1 28 13747 10754 11373 10110 8709 10886 10140 22796 62395 48953 47917 29379 24008.5 29 17185 14904 15532 13995 12899 11913 11334 17743 35207 43572 37728 23435 21356.9 30 13507 10552 10899 9859 8507 8381 9620 28528 43403 52897 40437 25320 21930.9 31 17473 14337 15423 14160 13459 12550 12315 21769 48311 63459 41664 23855 24993.9 32 17189 15842 15709 14739 14090 12746 11919 30994 38747 62541 67548 32460 28024.6 - Max 21537 16927 16009 14739 14090 12746 12315 42287 73798 63459 67548 44998 28024.6 Min 13142 9754 9989 9383 8134 8036 7508 10338 30358 36956 37728 20921 19068.6 fl'lean 15960 13082 13731 12687 11941 10843 9964 23415 46157 48584 47620 29689 23723.7 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.56. Table H.2-9.Predicted Postproject Monthly Flows (ft3/s)at Sunshine Under Combined Watana-Devi1 Canyon Operation Month Year Oct Nov Dec Jan Feb Mar Apr May Jun Ju1 Aug Sep Annual 1 14847 13990 14750 13371 12427 10172 8914 18232 33192 43785 46969 28733 21695.3 2 15127 10553 10839 9468 8139 8036 9085 36891 44637 53612 50686 39129 24806.6 3 14981 13389 14551 23597 12692 11262 8960 12034 46163 46449 44443 26877 22174.9 4 16499 15352 15048 13408 12735 11480 10895 42287 48825 40807 41344 27767 24791.3 5 14875 10240 14373 13683 12869 10562 9807 27185 38640 40182 43601 24756 21813.5 6 14105 10972 15007 13915 13100 12013 9261 19590 49987 52228 63942 31539 25573.7 7 13993 13591 14433 13257 12266 10348 8847 27079 52883 60568 58124 44495 27588.4 8 18234 15653 15448 14028 13249 12103 10541 28946 60408 46124 44703 38494 26550.7 9 21170 16927 16009 13899 12897 11878 11331 23867 44279 43952 46362 21848 23791.6 10 13883 104]1,10261 11932 13039 10419 9498 24198 49389 50470 53551 34598 24378.4 11 18113 15142 15373 14019 13029 11917 10484 29253.30358 42509 43725 31876 23076.1 12 16406 13856 15697 14333 13177 12274 12218 25978 44071 47907 50516 32001 24958.3 13 15737 14020 15401 14023 13076 12008 11076 19284 57265 50938 55163 38711 26458.7 14 16938 14585 15271 14171 13403 11755 9528 27126 42343 55209 41268 28413 24260.8 15 21537 15131 14638 13388 12672 10152 8984 10338 73798 45252 41934 22996 24264.4 16 16488 13869 15812 14014 12942 10957 10038 19373 42012 46387 47255 44998 24571.8 :::I: I 17 21190 14545 15023 13743 13002 11523 .10201 13951 49519 42764 52177 27706 23848.3 w 018143199908105281189613274109329242275014800660166 65319 37379 26652.5 19 13688 14483 15245 13952 13387 12508 11968 31433 57296 53787 41560 21369 25138.8 20 13142 9754 9989 10381 11711 10161 9045 18141 35920 36956 38648 24356 19068.6 21 13213 9975 10178 9383 8294 8349 8648 21053 36932 45953 46946 27370 20622.9 22 14491 11785 11140 9580 8134 8171 7508 13469 51973 47587 54609 28015 22292.2 23 17295 15137 15174 13886 13179 12093 11059 26670 45246 48984 43964 31056 24558.8 24 15215 14795 15107 13732 12998 11175 9424 16001 40412 39945 42795 25464 21479.0 25 14371 10280 10531 9432 8199 9598 9519 25918 32964 39274 39002 26164 19696.6 26 15413 10438 10443 9665 8217 8228 7557 23517 52448 58410 45588 28557 23313.0 27 16354 13462 141a5 12973 12335 10420 9897 18145 39997 43050 44355 20921 21418.1 28 13747 10754 11373 10110 8709 10886 10140 22796 62395 48953 47917 29379 24008.5 29 17185 14904 15532 13995 12899 11913 11334 17743 35207 43572 37728 23435 21356.9 30 13507 10552 10899 9859 8507 8381 9620 28528 43403 52897 40437 25320 21930.9 31 17473 14337 15423 14160 13459 12550 12315 21769 48311 63459 41664 23855 24993.9 32 17189 15842 15709 14739 14090 12746 11919 30994 38747 62541 67548 32460 28024.6 Max 21537 16927 16009 14739 14090 12746 12315 42287 73798 63459 67548 44998 28024.6 Min 13142 9754 9989 9383 8134 8036 7508 10338 30358 36956 37728 20921 19068.6 fl'lean 15960 13082 13731 12687 11941 10843 9964 23415 46157 48584 47620 29689 23723.7 Conversion:To convert from cubic feet to cubic meters,multiply by 0.0283. Source:Exhibit E,Table E.2.56. H-31NOTE:CURVESBASEDUPONAVERAGEMONTHLYFLOWSFOR32YEARSOFSYNTHESIZEDRECORDSDERIVEDFROMHISTORICALDATA.o501000LEGEND:PRE-PROJECTFLOWSWATANAOPERATIONFLOWSWATANA/DEVILCANYONFLOWSANNUALDECEMBER102L...L...L-I---l-.l-l.-L-.L...L..J105c=-r--,-,-.-.,--,.-,--r-r"=l102L...L~L....L..L...l---l-.l-l._105=-...,-,r-r--,-,-,-.,--,.~~E104wo0:::«G103(f)o102L..L..J...J-L.L-L-L.L..I.....Jo50100050100050100PERCENTOFTIMEDISCHARGEEQUALLEDOREXCEEDEDFigureH.2-5.FlowdurationcurvesatGoldCreekforpre-project,Watana,andWatana-DevilCanyonoperationalflows.Source:ExhibitE,FiguresE.2.160andE.2.208.H-31NOTE:CURVESBASEDUPONAVERAGEMONTHLYFLOWSFOR32YEARSOFSYNTHESIZEDRECORDSDERIVEDFROMHISTORICALDATA.o501000LEGEND:PRE-PROJECTFLOWSWATANAOPERATIONFLOWSWATANA/DEVILCANYONFLOWSANNUALDECEMBER102L...L...L-I---l-.l-l.-L-.L...L..J105c=-r--,-,-.-.,--,.-,--r-r"=l102L...L~L....L..L...l---l-.l-l._105=-...,-,r-r--,-,-,-.,--,.~~E104wo0:::«G103(f)o102L..L..J...J-L.L-L-L.L..I.....Jo50100050100050100PERCENTOFTIMEDISCHARGEEQUALLEDOREXCEEDEDFigureH.2-5.FlowdurationcurvesatGoldCreekforpre-project,Watana,andWatana-DevilCanyonoperationalflows.Source:ExhibitE,FiguresE.2.160andE.2.208. 103L...-L.~-'--'-'-l.-..l-J.......Jo50100050100050100PERCENTOFTIMEDISCHARGEEQUALLEDOREXCEEDED103L...-L.~-'--'-'-l.-..l-J..--'106FT",.--,,,-,-,-,-""-;-=l;;fE105Wl?ctc:t15104enoH-32o50100050100LEGEND:PRE-PROJECTFLOWSWATANAOPERATIONFLOWSWATANA/DEVILCANYONFLOWSNOTE:CURVESBASEDUPONAVERAGEMONTHLYFLOWSFOR32YEARSOFSYNTHESIZEDRECORDSDERIVEDFROMHISTORICALANDFILEDDATA.FigureH.2-6.FlowdurationcurvesatSunshineforpre-project,Watana,andWatana-DevilCanyonoperationalflows.Source:ExhibitE,FiguresE.2.l61andE.2.209.103L...-L.~-'--'-'-l.-..l-J.......Jo50100050100050100PERCENTOFTIMEDISCHARGEEQUALLEDOREXCEEDED103L...-L.~-'--'-'-l.-..l-J..--'106FT",.--,,,-,-,-,-""-;-=l;;fE105Wl?ctc:t15104enoH-32o50100050100LEGEND:PRE-PROJECTFLOWSWATANAOPERATIONFLOWSWATANA/DEVILCANYONFLOWSNOTE:CURVESBASEDUPONAVERAGEMONTHLYFLOWSFOR32YEARSOFSYNTHESIZEDRECORDSDERIVEDFROMHISTORICALANDFILEDDATA.FigureH.2-6.FlowdurationcurvesatSunshineforpre-project,Watana,andWatana-DevilCanyonoperationalflows.Source:ExhibitE,FiguresE.2.l61andE.2.209. 1000 1 I I I I I I ~ 500 I I I I I I I I I I I :c I W W 50 100 200 5001.25 2 5 10 20 RECURRENCE INTERVAL (YEARS) Ii.OBSERVED DATA o ESTIMATED DATA •95%CONFIDENCE LIMITS 1.05 WATANA /DEVIL CANYON OPERATION10IIII!I I !I I I 1.005 100 I----f-------J---.--+-----t--- 200 I I en '+-u ooo 5:o -l LL Figure H.2-7.Comparison of recurrence intervals for mean annual floods at Gold Creek under preproject,Watana,and Watana-Devil Canyon operational flow regimes.Source: Exhibit E,Figures E.2.29,E.2.l55,and E.2.l86. 500 1-----1-------if-------I------t---+--l---+--+--I----l :c I W W 50 100 200 5001.25 2 5 10 20 RECURRENCE INTERVAL (YEARS) Ii.OBSERVED DATA o ESTIMATED DATA •95%CONFIDENCE LIMITS 1.05 WATANA /DEVIL CANYON OPERATION10'--__..l..--..l........l-...L-_---l__I--_-l...----L._-'-----l 1.005 100 1-----t------1f--------I------t--~~~ 2001----+en '+-u ooo Figure H.2-7.Comparison of recurrence intervals for mean annual floods at Gold Creek under preproject,Watana,and Watana-Devil Canyon operational flow regimes.Source: Exhibit E,Figures E.2.29,E.2.l55,and E.2.l86. H-34TableH.3-1.ThresholdsinMainstemFlow(ft3/s)atWhichHydraulicRegimesOccuratSelectedSide-ChannelSloughsHydraulicRegimeIIIIIILocationOvertoppingBackwaterIsolationAboveTalkeetnatlSlough8A(RM)30,00026,000-10,00010,000Slough9(RM)23,00020,500-11,00011,000Slough21(RM)26,00024,800-21,40021,400Average26,00026,000-14,00014,000BelowTalkeetnat2RabideauSlough65,00065,000-10,00010,000tlFlowsincubicfeetpersecondattheGoldCreekgagingstation.t2FlowsincubicfeetpersecondattheSunshinegagingstation.Conversion:Toconvertfromcubicfeettocubicmeters,mulitplyby0.0283.Source:ExnibitE,AppendixE.2.A,TableA-l.H-34TableH.3-1.ThresholdsinMainstemFlow(ft3/s)atWhichHydraulicRegimesOccuratSelectedSide-ChannelSloughsHydraulicRegimeIIIIIILocationOvertoppingBackwaterIsolationAboveTalkeetnatlSlough8A(RM)30,00026,000-10,00010,000Slough9(RM)23,00020,500-11,00011,000Slough21(RM)26,00024,800-21,40021,400Average26,00026,000-14,00014,000BelowTalkeetnat2RabideauSlough65,00065,000-10,00010,000tlFlowsincubicfeetpersecondattheGoldCreekgagingstation.t2FlowsincubicfeetpersecondattheSunshinegagingstation.Conversion:Toconvertfromcubicfeettocubicmeters,mulitplyby0.0283.Source:ExnibitE,AppendixE.2.A,TableA-l. H-35TableH.3-2.FrequencyofOccurrenceofVariousHydraulicRegimesofSideSloughsinOpenwaterSeasonBeforeandAfterProjectBeginsOperations(AssumesAverageThresholdsof26,000,14,000to26,000and14,000ft3/sforSloughsAboveTalkeetnaand65,000,65,000to10,000,and10,000ft3/sBelowTalkeetnaforRegimesI,II,andIII,Respectively)PostprojectRegimest2(WatanaAlone)PreprojectRegimestlMonthIIIIIISloughsAboveTalkeetnaMay153853June53434July39583August26.6311September63262October0496RabideauxSloughBelowTalkeetnaMay08614June49510July61390August23770September2980October08812t1Preprojectanalysisbasedonaveragedailyflows.t2Postprojectanalysisbasedonaveragemonthlyflows.o1o1ooo10o14ooo12216oo75901008610010010087988310010025oooooConversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:FERCstaffH-35TableH.3-2.FrequencyofOccurrenceofVariousHydraulicRegimesofSideSloughsinOpenwaterSeasonBeforeandAfterProjectBeginsOperations(AssumesAverageThresholdsof26,000,14,000to26,000and14,000ft3/sforSloughsAboveTalkeetnaand65,000,65,000to10,000,and10,000ft3/sBelowTalkeetnaforRegimesI,II,andIII,Respectively)PostprojectRegimest2(WatanaAlone)PreprojectRegimestlMonthIIIIIISloughsAboveTalkeetnaMay153853June53434July39583August26.6311September63262October0496RabideauxSloughBelowTalkeetnaMay08614June49510July61390August23770September2980October08812t1Preprojectanalysisbasedonaveragedailyflows.t2Postprojectanalysisbasedonaveragemonthlyflows.o1o1ooo10o14ooo12216oo75901008610010010087988310010025oooooConversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:FERCstaff H-36time,respectively)aboveTalkeetna.WhileovertoppinghadbeenthemostfrequentlyoccurringconditioninJune(53%preprojectoccurrence),itwouldbeeffectivelyeliminatedunderthebackwaterregime.Isolationconditions(RegimeIII)wouldpersistthroughouttheopen-waterseason.SincetheflowregimewithcombinedWatana-DevilCanyonoperationwouldbeverysimilartothatofWatanaalone,thesloughhydraulicregimeswouldalsobesimilar.However,duringfillingofthereservoirs,downstreamflowswouldbeequaltotheproposedminimumflowsof12,000ft3/s(340m3/s)(Aug.1 -Sept.15)and5,000ft3/s(142m3/s)atothertimes.ItisobviousfromtheApplicant-definedflowthresholds(TableH.3-1)thatthesefillingflowswouldresultinextremeisolationoftheside-channelsloughsaboveTalkeetna.TneonlysloughstudiedforhydraulicregimesbelowTalkeetnawasRabideauSlough(TableH.3-1).AlthoughitwouldnotbeimpactedasmuchasthesloughsaboveTalkeetna,RabideauSloughwouldbesubjectedtoasignificantreductioninthefrequencyofovertoppingthroughouttneopen-watermonths(TableH.3-2).Itwouldnotbeisolatedfromthemainchanneltoanysignificantdegree,butthismaybedueonlytotheuniquecharacteristicsofthissite.Hydraulic-regimethresholdsformoresloughsbelowTalkeetnaneedtobestudiedbeforethetrendsinTableH.3-2canbeverified.Theprecedingdiscussioninthissectionappliesonlytotheopen-watermonthsontheSusitnaRiver.Duringtheice-coverseason,theflowthresholdsfortheovertoppingandbackwaterregimeswouldbelowerduetotheeffectsofice-inducedstaginginthemainchannel.Thedegreeofstagingwouldvaryalongtheriverduetolocalizedice-jammingandtheproximityofhydrauliccontrols.Flowthresholdsforhydraulicconditionssuchasovertoppinghavenotbeenestablished,butitispossibletoestimatetheamountofstagingthatmightberequiredtocauseovertopping.Themaximumwinterflowhasbeenestimatedatabout15,000ft3/s(425m3/s)atGoldCreek.ThiswouldoccurwhenthepowerhouseatWatanawasatfullgeneratingcapacity,whichcanbeassumedtooccurquitefrequently,sincewinterwouldbethepeakdemandperiod.Theamountofmainstemstagingrequiredtocauseovertoppingatsloughs8A,9,and21isapproximately2ft(0.6m)(Table-H.3-3).Thisamountofstagingcouldeasilyoccur;therefore,winterovertoppingislikelytobeafrequentphenomenon.TableH.3-3.CalculationofIce-RelatedStagingRequiredforWinterOvertoppingofSelectedSloughsSlough8ASlough9Slough21RiverMileatupstreambermtl126.1129.2142.2Overtoppingflow(ft3/s)tl30,00023,00026,000Watersurfaceelevations(ft)t2@Overtopping573.8602.7756.8@15,000ft3/s572.0601.2754.6Icestagingneeded1.81.52.2forwinterovertopping(ft)tlFromExhibitE,AppendixE.2.A.t2FromExhibitE,TableE.2.l5.Conversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Toconvertfromfeettometers,multiplyby0.3048.Source:FERCstaffH-36time,respectively)aboveTalkeetna.WhileovertoppinghadbeenthemostfrequentlyoccurringconditioninJune(53%preprojectoccurrence),itwouldbeeffectivelyeliminatedunderthebackwaterregime.Isolationconditions(RegimeIII)wouldpersistthroughouttheopen-waterseason.SincetheflowregimewithcombinedWatana-DevilCanyonoperationwouldbeverysimilartothatofWatanaalone,thesloughhydraulicregimeswouldalsobesimilar.However,duringfillingofthereservoirs,downstreamflowswouldbeequaltotheproposedminimumflowsof12,000ft3/s(340m3/s)(Aug.1 -Sept.15)and5,000ft3/s(142m3/s)atothertimes.ItisobviousfromtheApplicant-definedflowthresholds(TableH.3-1)thatthesefillingflowswouldresultinextremeisolationoftheside-channelsloughsaboveTalkeetna.TneonlysloughstudiedforhydraulicregimesbelowTalkeetnawasRabideauSlough(TableH.3-1).AlthoughitwouldnotbeimpactedasmuchasthesloughsaboveTalkeetna,RabideauSloughwouldbesubjectedtoasignificantreductioninthefrequencyofovertoppingthroughouttneopen-watermonths(TableH.3-2).Itwouldnotbeisolatedfromthemainchanneltoanysignificantdegree,butthismaybedueonlytotheuniquecharacteristicsofthissite.Hydraulic-regimethresholdsformoresloughsbelowTalkeetnaneedtobestudiedbeforethetrendsinTableH.3-2canbeverified.Theprecedingdiscussioninthissectionappliesonlytotheopen-watermonthsontheSusitnaRiver.Duringtheice-coverseason,theflowthresholdsfortheovertoppingandbackwaterregimeswouldbelowerduetotheeffectsofice-inducedstaginginthemainchannel.Thedegreeofstagingwouldvaryalongtheriverduetolocalizedice-jammingandtheproximityofhydrauliccontrols.Flowthresholdsforhydraulicconditionssuchasovertoppinghavenotbeenestablished,butitispossibletoestimatetheamountofstagingthatmightberequiredtocauseovertopping.Themaximumwinterflowhasbeenestimatedatabout15,000ft3/s(425m3/s)atGoldCreek.ThiswouldoccurwhenthepowerhouseatWatanawasatfullgeneratingcapacity,whichcanbeassumedtooccurquitefrequently,sincewinterwouldbethepeakdemandperiod.Theamountofmainstemstagingrequiredtocauseovertoppingatsloughs8A,9,and21isapproximately2ft(0.6m)(Table-H.3-3).Thisamountofstagingcouldeasilyoccur;therefore,winterovertoppingislikelytobeafrequentphenomenon.TableH.3-3.CalculationofIce-RelatedStagingRequiredforWinterOvertoppingofSelectedSloughsSlough8ASlough9Slough21RiverMileatupstreambermtl126.1129.2142.2Overtoppingflow(ft3/s)tl30,00023,00026,000Watersurfaceelevations(ft)t2@Overtopping573.8602.7756.8@15,000ft3/s572.0601.2754.6Icestagingneeded1.81.52.2forwinterovertopping(ft)tlFromExhibitE,AppendixE.2.A.t2FromExhibitE,TableE.2.l5.Conversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Toconvertfromfeettometers,multiplyby0.3048.Source:FERCstaff H-37SloughAccessibilityMainstemflowsatwhichselectedsloughsareaccessibletosalmonwereidentifiedbytheAlaskaDepartmentofFishandGame(ADFG)(TableH.3-4).OftheninesloughsstudiedforaccessibilitybyADFG(1983),sloughs6Aand19areuplandsloughsandalltheothersareside-channelsloughs.Thefrequencyatwhichthesethresholdsareequaledorexceededwasexaminedbyusingthepreproject,Watana,andcombinedWatana-Devi1Canyonoperationalflows(FiguresH.2-5andH.2-6).Resultsofthisinitialanalysis,whichignoredutilization,areshowninTableH.3-5.Acumulativeaccessibilityanalysiswasalsocarriedouttoexamineoverallavailabilityofqualityspawninghabitatinthesloughs.Arelativevaluewasassignedtoeachslough,basedontheobservedutilizationinthe1981and1982seasons(TableH.3-4).Sloughswithhigh,medium,low,andnoutilizationreceivedvaluesof1,2/3,1/3,and0,respectively.Thecumulativepercentoftheseweightedspawningvalueswasthenplottedagainstmainstemflows(FigureH.3-1).Thisanalysisindicatesthat50%oftheweightedspawnin~habitatinthesloughsstudiedhasunrestrictedaccessatGoldCreekflowsabove12,500ft/s(354m3/s).However,thesecond50%ofweightedsloughspawninghabitathasacuteaccesslimitationsuntilmainchannelflowsexceed18,000ft3/s(510m3/s).WettedSurfaceAreainSloughsTheADFG(1983)publisheddataonwettedsurfaceareavs.mainstemflowforninesloughsaboveTalkeetna(TableH.3-6)andfivesloughsbelowTalkeetna(TableH.3-7).Theseresponsedataincludedtotalwettedsurfaceareaindependentofmicrohabitattypeandahabitattypecalled"backwaterH-IIzones."TheseH-IIzonesarebackwaterareas,notdire§t1yconnectedtothemainchannel,whichhaveameanvelocitylessthan0.5ft/s(0.15mIs)(ADFG1983).Changesingeneralizedsloughhabitatwereexaminedbyconvertingthepreproject,Watana,andcombinedWatanaoperationalflowsintowettedsurfaceareavaluesforeachsloughandmonthintheflowrecord.ChangeinsurfaceareaforeachsloughandmonthcombinationwascalculatedasDAREAi=100(SApre,i-SApost,i)/SApre,iwhereDAREAiisthepercentchangeinwettedsurfaceareafortheithmonthintheflowrecord~SApreiisthesurfaceareacalculatedfrommeanmonthlypreprojectflowduringtheitnmonth'intheflowrecord,andSAoostiisthesurfaceareacalculatedfromthesimulatedpostprojectflowfortheitnmonthoftherecord.TheresultingrecordofDAREAvalueswasthensubjectedtoafrequencyanalysisaswellasothersimplestatisticalanalyses.FigureH.3-2showsthemeanpercentchangeintotalwettedsurfaceareawitherrorbarsofplus/minusonestandarddeviationforfilling,Watana,andWatana-Devi1Canyonoperations.TheresponseofcumulateareaintheH-IIzonestomainstemflowsisshowninFigureH.3-3.H-37SloughAccessibilityMainstemflowsatwhichselectedsloughsareaccessibletosalmonwereidentifiedbytheAlaskaDepartmentofFishandGame(ADFG)(TableH.3-4).OftheninesloughsstudiedforaccessibilitybyADFG(1983),sloughs6Aand19areuplandsloughsandalltheothersareside-channelsloughs.Thefrequencyatwhichthesethresholdsareequaledorexceededwasexaminedbyusingthepreproject,Watana,andcombinedWatana-Devi1Canyonoperationalflows(FiguresH.2-5andH.2-6).Resultsofthisinitialanalysis,whichignoredutilization,areshowninTableH.3-5.Acumulativeaccessibilityanalysiswasalsocarriedouttoexamineoverallavailabilityofqualityspawninghabitatinthesloughs.Arelativevaluewasassignedtoeachslough,basedontheobservedutilizationinthe1981and1982seasons(TableH.3-4).Sloughswithhigh,medium,low,andnoutilizationreceivedvaluesof1,2/3,1/3,and0,respectively.Thecumulativepercentoftheseweightedspawningvalueswasthenplottedagainstmainstemflows(FigureH.3-1).Thisanalysisindicatesthat50%oftheweightedspawnin~habitatinthesloughsstudiedhasunrestrictedaccessatGoldCreekflowsabove12,500ft/s(354m3/s).However,thesecond50%ofweightedsloughspawninghabitathasacuteaccesslimitationsuntilmainchannelflowsexceed18,000ft3/s(510m3/s).WettedSurfaceAreainSloughsTheADFG(1983)publisheddataonwettedsurfaceareavs.mainstemflowforninesloughsaboveTalkeetna(TableH.3-6)andfivesloughsbelowTalkeetna(TableH.3-7).Theseresponsedataincludedtotalwettedsurfaceareaindependentofmicrohabitattypeandahabitattypecalled"backwaterH-IIzones."TheseH-IIzonesarebackwaterareas,notdire§t1yconnectedtothemainchannel,whichhaveameanvelocitylessthan0.5ft/s(0.15mIs)(ADFG1983).Changesingeneralizedsloughhabitatwereexaminedbyconvertingthepreproject,Watana,andcombinedWatanaoperationalflowsintowettedsurfaceareavaluesforeachsloughandmonthintheflowrecord.ChangeinsurfaceareaforeachsloughandmonthcombinationwascalculatedasDAREAi=100(SApre,i-SApost,i)/SApre,iwhereDAREAiisthepercentchangeinwettedsurfaceareafortheithmonthintheflowrecord~SApreiisthesurfaceareacalculatedfrommeanmonthlypreprojectflowduringtheitnmonth'intheflowrecord,andSAoostiisthesurfaceareacalculatedfromthesimulatedpostprojectflowfortheitnmonthoftherecord.TheresultingrecordofDAREAvalueswasthensubjectedtoafrequencyanalysisaswellasothersimplestatisticalanalyses.FigureH.3-2showsthemeanpercentchangeintotalwettedsurfaceareawitherrorbarsofplus/minusonestandarddeviationforfilling,Watana,andWatana-Devi1Canyonoperations.TheresponseofcumulateareaintheH-IIzonestomainstemflowsisshowninFigureH.3-3. H-38TableH.3-4.AccessThresholdsofMainstemDischargeatGoldCreekforSelectedSide-ChannelSloughsBetweenDevilCanyonandTalkeetna,IncludingRelativeUtilizationbyAdultSalmonin1981and1982tlHigh=chumsalmonexceed100perslough,frequentlymorethan1000perslough.Medium=zeroto100fishpersloughforchum,sockeye,andpinks.Low=atleastonespeciesobserved.None=nosalmonobserved.LowMediumHighHighHighNoneMediumHighLowRelativeUtilizationt110,0008,00012,50020,0006,70026,40021,50023,00022,500UnrestrictedAccessThresholds(ft3/s)8,000unavailable7,86018,000unavailable18,00020,00020,00020,000AcuteLimitationsWiskersCreek(RM101.2)Slough6A(RM112.3)Slough8A(RM125.3)Slough9(RM129.2)Slough11(RM135.3)Slough16B(RM138.0)Slough20(RM140.1)Slough21(RM142.0)Slough22(RM144.3)Slough(RiverMile)Conversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:AlaskaDepartmentofFishandGame(1983).TableH.3-5.FrequencyofAccessLimitationsinSelectedSloughsPercentOccurrencet1PreprojectWatanaWatana-DevilCanyonMonthAcuteMinorNoneAcuteMinorNoneAcuteMinorNoneMay54937601426651619June8983561430611425July61975631621671617August16216352939541135September511237561925551827October762046916 15711415t1percentofthemonthsinhistoricalrecordorinapplicant'ssimulatedpostprojectflowrecordinwhicheachconditionoccurs;"minor"indicatesflowsarebetweenthethresholdsforacutelimitationsandunrestrictedaccess.Source:FERCstaff.H-38TableH.3-4.AccessThresholdsofMainstemDischargeatGoldCreekforSelectedSide-ChannelSloughsBetweenDevilCanyonandTalkeetna,IncludingRelativeUtilizationbyAdultSalmonin1981and1982tlHigh=chumsalmonexceed100perslough,frequentlymorethan1000perslough.Medium=zeroto100fishpersloughforchum,sockeye,andpinks.Low=atleastonespeciesobserved.None=nosalmonobserved.LowMediumHighHighHighNoneMediumHighLowRelativeUtilizationt110,0008,00012,50020,0006,70026,40021,50023,00022,500UnrestrictedAccessThresholds(ft3/s)8,000unavailable7,86018,000unavailable18,00020,00020,00020,000AcuteLimitationsWiskersCreek(RM101.2)Slough6A(RM112.3)Slough8A(RM125.3)Slough9(RM129.2)Slough11(RM135.3)Slough16B(RM138.0)Slough20(RM140.1)Slough21(RM142.0)Slough22(RM144.3)Slough(RiverMile)Conversion:Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:AlaskaDepartmentofFishandGame(1983).TableH.3-5.FrequencyofAccessLimitationsinSelectedSloughsPercentOccurrencet1PreprojectWatanaWatana-DevilCanyonMonthAcuteMinorNoneAcuteMinorNoneAcuteMinorNoneMay54937601426651619June8983561430611425July61975631621671617August16216352939541135September511237561925551827October762046916 15711415t1percentofthemonthsinhistoricalrecordorinapplicant'ssimulatedpostprojectflowrecordinwhicheachconditionoccurs;"minor"indicatesflowsarebetweenthethresholdsforacutelimitationsandunrestrictedaccess.Source:FERCstaff. H-39t-=0.3:wOCf)...JIlL..ci·::::>~<t:::iE•\\\\.\\\\.-----~\r\---------.i255050OL---...L.J...---...I.-------"L..-__--'-__---'100.....-----.r---.-.,.---.----,----.----,OL--_-L..__---l.....l.-__o510152025DISCHARGEATGOLDCREEK(103ft3/S>100r------,----,----r------r--ClWI-(,)0::~I-_Cf)Cf)wI0::<.!>Z::::>::::>gCf)lL..°>-I-...JiIi(j)Cf)W(,)(,)<t~ ~75_01-1=<t(,)...J-wO::0::1-Cf)w0::WI-::::>(,)<t2575FigureH.3-1.Cumulativeresponseofsloughaccessibilitytomainstemdischarge(dashedlineinbottomgraphassumesaacuteaccessibilitythresholdatSloughs6Aand11at5,000cfs).H-39t-=0.3:wOCf)...JIlL..ci·::::>~<t:::iE•\\\\.\\\\e-----~\r\---------ei255050OL---...L.J...---...I.-------"L..-__--'-__---'100.....-----.r---.-.,.---.----,----.----,OL--_-L..__---l.....l.-__o510152025DISCHARGEATGOLDCREEK(103ft3/S>100r------,----,----r------r--ClWI-(,)0::~I-_Cf)Cf)wI0::<.!>Z::::>::::>gCf)lL..°>-I-...JiIi(j)Cf)W(,)(,)<t~~75_01-1=<t(,)...J-wO::0::1-Cf)w0::WI-::::>(,)<t2575FigureH.3-1.Cumulativeresponseofsloughaccessibilitytomainstemdischarge(dashedlineinbottomgraphassumesaacuteaccessibilitythresholdatSloughs6Aand11at5,000cfs). TableH.3-6.WettedSurfaceAreas(103ft2)inSloughsAboveTalkeetnaSlough21Total88129160161163173194H-IIzone5264 694216412Slough20Total57698294106118130H-IIzone20.40 0002Slough19Total1620 2632384444H-IIzone40911142626Slough11Total587797116136 143 145H-IIzone22324673105 109110Slough9Total150171193215237 259280H-IIzone1084128109774411Slough8ATotal186194201208215 223230H-IIzone156164 173182190 199208LaneCreek/Slough8Total353943475155 59H-IIzone6914 14164547Slough6ATotal128129131132134135137H-IIzone128129131132 134 135137WiskersCreekTotal170179189198208217218H-IIzone29385266808484Conversion:Toconvertfromsquarefeettosquaremeters,multiplyby0.0929.Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:AlaskaDepartmentofFishandGame(1983).Location12.5H-40DischargeatGoldCreek(103ft3/s)1517.52022.52527.5TableH.3-6.WettedSurfaceAreas(103ft2)inSloughsAboveTalkeetnaSlough21Total88129160161163173194H-IIzone5264 694216412Slough20Total57698294106118130H-IIzone20.40 0002Slough19Total1620 2632384444H-IIzone40911142626Slough11Total587797116136 143 145H-IIzone22324673105 109110Slough9Total150171193215237 259280H-IIzone1084128109774411Slough8ATotal186194201208215 223230H-IIzone156164 173182190 199208LaneCreek/Slough8Total353943475155 59H-IIzone6914 14164547Slough6ATotal128129131132134135137H-IIzone128129131132 134 135137WiskersCreekTotal170179189198208217218H-IIzone29385266808484Conversion:Toconvertfromsquarefeettosquaremeters,multiplyby0.0929.Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:AlaskaDepartmentofFishandGame(1983).Location12.5H-40DischargeatGoldCreek(103ft3/s)1517.52022.52527.5 H-4lTableH.3-7.WettedSurfaceAreas(103ft2)inSloughsBelowTalkeetnaDischargeatGoldCreek(103ft3/s)Location354045505560 65 70BirchCreekTotal362368374380386394400 406H-IIzone84147150153225365378385SunshineCreekTotal168 185202219236253 270287H-IIzone255586118148178128121RabideauCreekTotal10201050107011101120115011801200H-IIzone4968268809339871040 10901150WhitefishSloughTotal2137516167727780H-IIzone2137516167727780GooseCreekTotal139143 148152 157161166170H-IIzone058117109103948678Conversion:Toconvertfromsquarefeettosquaremeters,multiplyby0.0929.Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:AlaskaDepartmentofFishandGame(1983).H-4lTableH.3-7.WettedSurfaceAreas(103ft2)inSloughsBelowTalkeetnaDischargeatGoldCreek(103ft3/s)Location354045505560 65 70BirchCreekTotal362368374380386394400 406H-IIzone84147150153225365378385SunshineCreekTotal168 185202219236253 270287H-IIzone255586118148178128121RabideauCreekTotal10201050107011101120115011801200H-IIzone4968268809339871040 10901150WhitefishSloughTotal2137516167727780H-IIzone2137516167727780GooseCreekTotal139143 148152 157161166170H-IIzone058117109103948678Conversion:Toconvertfromsquarefeettosquaremeters,multiplyby0.0929.Toconvertfromcubicfeettocubicmeters,multiplyby0.0283.Source:AlaskaDepartmentofFishandGame(1983). PREPROJECTvsWATANA/DEVILCANYONALLSITESCOMBINEDI--------1/-f-\V-;l-'f--f--I I III IIPREPROJECTvsWATANA/OEVILCANYONALLSITESCOMBINEDPREPROJECTvsWATANAALLSITESCOMBINEDPREPROJECTvsWATANAALLSITESCOMBINEDI I I I-f------\1/-r-NlJ---SIDESLOUGHSBELOWTALKEETNAPREPRDJECTvsFILLINGALLSITESCOMBINEOSIDESLOUGHSABOVETALKEETNAH-42-80FigureH.3-2.ResponseofZoneH-IIwettedsurfaceareatomainstemflows.Source:ADFG1983.-60-40_100L-L-L-.L-.L-..l-...l-...l-...l-...l-...L-....JJFMAMJJASONOJFMAMJJASONOJFMAMJJASONOMONTHOFTHEYEAR100806040200-20~w-40a:~w-60u~u..-80a:::Jen-100~w<.:J100z~I80ur-z60wua:40wa..200-20PREPROJECTvsWATANA/DEVILCANYONALLSITESCOMBINEDI--------1/-f-\V-;l-'f--f--I I III IIPREPROJECTvsWATANA/OEVILCANYONALLSITESCOMBINEDPREPROJECTvsWATANAALLSITESCOMBINEDPREPROJECTvsWATANAALLSITESCOMBINEDI I I I-f------\1/-r-NlJ---SIDESLOUGHSBELOWTALKEETNAPREPRDJECTvsFILLINGALLSITESCOMBINEOSIDESLOUGHSABOVETALKEETNAH-42-80FigureH.3-2.ResponseofZoneH-IIwettedsurfaceareatomainstemflows.Source:ADFG1983.-60-40_100L-L-L-.L-.L-..l-...l-...l-...l-...l-...L-....JJFMAMJJASONOJFMAMJJASONOJFMAMJJASONOMONTHOFTHEYEAR100806040200-20~w-40a:~w-60u~u..-80a:::Jen-100~w<.:J100z~I80ur-z60wua:40wa..200-20 H-4330,,-_.()--,-{)---U-_-Q_(0)SITESABOVETALKEETNA///////////(b)SITESBELOW.TALKEETNA510 152025DISCHARGEATGOLDCREEK(103cfs)~100>-I-W0I-«(9wa::(9~2000.-------,-----,-----r-----r------r----,l.1..o«wa::«1500wu«l.1..a:::::>(J)...J1000~oI-700600500N......-r<l4000~~a::300wI-«~200I=l500///I/o2030405060DISCHARGEATSUNSHINE(103ft2/S)70FigureH.3-3.Changesintotalwettedsurfaceareainsloughsduringfilling,Watana,andWatana-DevilCanyonoperationalflows.H-4330,,-_.()--,-{)---U-_-Q_(0)SITESABOVETALKEETNA///////////(b)SITESBELOW.TALKEETNA510 152025DISCHARGEATGOLDCREEK(103cfs)~100>-I-W0I-«(9wa::(9~2000.-------,-----,-----r-----r------r----,l.1..o«wa::«1500wu«l.1..a:::::>(J)...J1000~oI-700600500N......-r<l4000~~a::300wI-«~200I=l500///I/o2030405060DISCHARGEATSUNSHINE(103ft2/S)70FigureH.3-3.Changesintotalwettedsurfaceareainsloughsduringfilling,Watana,andWatana-DevilCanyonoperationalflows. H-44H.4TEMPERATUREThermalModelPredictionoftemperaturesdownstreamofthedamsismadeusingananalyticmodelwhichrelatesthetime-rate-of-changeofwatertemperaturetothesumoftheheatfluxcomponentsacrossthewatersurface.Thecomponentsconsideredinthismodelinclude(1)incomingsolarirradiation,(2)infraredbackradiation,(3)evaporation,and(4)convection.TheformulationofthesefluxtermsisgivenbyEraslan(1983)anddescribedbelow:(1)SolarIrradiation-qSR=QSR=constantQSRisnormallymodifiedbyasinefunctiontoaccountforvariationsininsolationduringthedaylighthoursandtheabsenceofinsolationatnight.Forthelatefall/earlysummersimulationQSRwastakenaszeroduetothesmallnumberofdaylighthours.ForthesummersimulationQSRcanbeassumedconstantduetothelargenumberofdaylighthours.NovalueofQSRisavailableforthesitevicinitysoanestimatedvalueof341W/m2-oKwasused.Itisnotbelievedthattheuncertaintyinthisnumberinfluencesthetemperaturepredictions.Toverifythishypothesis,thevalueofQSRwasdoubledtoyieldavaluewhichwouldberealisticfornorthernCalifornia,andthemodelsubsequentlyreapplied.ThislargechangeinQSRonlyproduceda1°Cincreasedinpredictedwatertemperatureover50rivermiles.(2)BackRadiation-qBR= -0.8o[T+273J4Backradiationisrepresentedbyblackbodyradiationwhere0istheStefan-BoltzmannconstantandTisthewatertemperature.The0.8factorreflectsthefactthatwaterradiateslessefficientlythanablackbody.(3)Evaporation-qev= - hev(1-Rh)(1+Vw/Vref)(T- Ta) H(T- Ta)1forT>TaH(T- Ta)=oforT~TaInthisformulationhevisasurfacefilmcoefficient,11.4W/m2-oK,Rhistherelativehumidity,Vwisthewindspeed,VrefisareferencewindspeedandTaistheairtemperature.ForthesimulationsperformedRhandVwwereassumedtobezeroandavalueofTa=12.20(wastakenforthelatefall/earlywintercase,andavalueofTa=15.5°Cwasusedinthesummercase.(4)Convection-qCN=-hCN(1+Vw/Vref)(T- Ta)TheparametersVw,Vref,andTaaredescribedanddefinedunderevaporation.ThecoefficienthCN= hev•Theresultingmodelequationisgivenbywheretistime,pisthedensityofwater,1000kg/m3,andCisthespecificheatofwater,4186J/kg-OK,andDisthelocalwaterdepth.TheaboveequationcanbeintegratedtoyieldT =Toute-At/D+B(l-e-At/D)whereToutistheoutlettemperatureatthedamandA =[hCN(1+Vw/Vref)+6.5x107p + hev(1-Rh)(1+Vw/Vref)J/pCandB =[QSR+hCN(1+Vw/Vref)Ta+ hev(1-Rh)(1+Vw/Vref)-4.4x109oJ/pC.Time,t,canbereplacedbydownstreamdistance,x,throughtherelationshipt =x/u,whereuthelocalflowvelocitywhich,inturn,isrelatedtothedischargeQ,theriverwidthw,andobyu =Q/WD.Thusthetemperatureatcross-sectioni+lcanbedeterminedbaseduponthetemperatureatcross-sectionibyTi+1=Tie-Ati+l/Di+l+ B(1-e-Ati+l/Di+l)wnereti+l=ti+WiDi(xi+l-xi)/Q,t9= xQ=0,andTo=Tout.ValueofWiandDiarebasedonchannelcross-sectionsprovidedinR&M\1982).H-44H.4TEMPERATUREThermalModelPredictionoftemperaturesdownstreamofthedamsismadeusingananalyticmodelwhichrelatesthetime-rate-of-changeofwatertemperaturetothesumoftheheatfluxcomponentsacrossthewatersurface.Thecomponentsconsideredinthismodelinclude(1)incomingsolarirradiation,(2)infraredbackradiation,(3)evaporation,and(4)convection.TheformulationofthesefluxtermsisgivenbyEraslan(1983)anddescribedbelow:(1)SolarIrradiation-qSR=QSR=constantQSRisnormallymodifiedbyasinefunctiontoaccountforvariationsininsolationduringthedaylighthoursandtheabsenceofinsolationatnight.Forthelatefall/earlysummersimulationQSRwastakenaszeroduetothesmallnumberofdaylighthours.ForthesummersimulationQSRcanbeassumedconstantduetothelargenumberofdaylighthours.NovalueofQSRisavailableforthesitevicinitysoanestimatedvalueof341W/m2-oKwasused.Itisnotbelievedthattheuncertaintyinthisnumberinfluencesthetemperaturepredictions.Toverifythishypothesis,thevalueofQSRwasdoubledtoyieldavaluewhichwouldberealisticfornorthernCalifornia,andthemodelsubsequentlyreapplied.ThislargechangeinQSRonlyproduceda1°Cincreasedinpredictedwatertemperatureover50rivermiles.(2)BackRadiation-qBR= -0.8o[T+273J4Backradiationisrepresentedbyblackbodyradiationwhere0istheStefan-BoltzmannconstantandTisthewatertemperature.The0.8factorreflectsthefactthatwaterradiateslessefficientlythanablackbody.(3)Evaporation-qev= - hev(1-Rh)(1+Vw/Vref)(T- Ta) H(T- Ta)1forT>TaH(T- Ta)=oforT~TaInthisformulationhevisasurfacefilmcoefficient,11.4W/m2-oK,Rhistherelativehumidity,Vwisthewindspeed,VrefisareferencewindspeedandTaistheairtemperature.ForthesimulationsperformedRhandVwwereassumedtobezeroandavalueofTa=12.20(wastakenforthelatefall/earlywintercase,andavalueofTa=15.5°Cwasusedinthesummercase.(4)Convection-qCN=-hCN(1+Vw/Vref)(T- Ta)TheparametersVw,Vref,andTaaredescribedanddefinedunderevaporation.ThecoefficienthCN= hev•Theresultingmodelequationisgivenbywheretistime,pisthedensityofwater,1000kg/m3,andCisthespecificheatofwater,4186J/kg-OK,andDisthelocalwaterdepth.TheaboveequationcanbeintegratedtoyieldT =Toute-At/D+B(l-e-At/D)whereToutistheoutlettemperatureatthedamandA =[hCN(1+Vw/Vref)+6.5x107p + hev(1-Rh)(1+Vw/Vref)J/pCandB =[QSR+hCN(1+Vw/Vref)Ta+ hev(1-Rh)(1+Vw/Vref)-4.4x109oJ/pC.Time,t,canbereplacedbydownstreamdistance,x,throughtherelationshipt =x/u,whereuthelocalflowvelocitywhich,inturn,isrelatedtothedischargeQ,theriverwidthw,andobyu =Q/WD.Thusthetemperatureatcross-sectioni+lcanbedeterminedbaseduponthetemperatureatcross-sectionibyTi+1=Tie-Ati+l/Di+l+ B(1-e-Ati+l/Di+l)wnereti+l=ti+WiDi(xi+l-xi)/Q,t9= xQ=0,andTo=Tout.ValueofWiandDiarebasedonchannelcross-sectionsprovidedinR&M\1982). H-45H.5SURFACEWATERQUALITYH.5.1SalinityTheSusitnaRiverisamajorcontributoroffreshwatertoCookInlet,withthemeasuredflowatGoldCreekaccountingforapproximately19%ofthemeasuredflowatSusitnaStationnearCookInlet(ExhibitE,Chapter2).Assuch,theSusitnaRiverhasamajorinfluenceonthesalinityoftheupperCookInlet.Atnode27nearthemouthoftheSusitnaRiver(FigureH.5.1-1),salinityrangesannuallyfromapproximately6to21partsperthousand(ppt)(g/L)(FigureH.5.1-2).AsoneproceedsdownCookInlettowardtheGulfofAlaska,thesalinityincreases,approachingthatofseawater(FigureH.5.1-2),andtheannualvariationinsalinitydecreases,owingtothedeclininginfluenceoffreshwaterinputstoCookInlet.H.5.2SuspendedSolidsToassesstheeffectofdredgingforWatanaDamonsuspendedsedimentsintheSusitnaRiver,theincrementalincreaseinsuspendedsolidswascalculatedbyassumingthatacertainfractionofdredgedmaterialwouldbelosttoentrainmentinriverwater.ResultsofgeotechnicalsurveysconductedattheWatanaDamsiteindicatethatalluvialdepositsintheriverchannelupstreamofwheredredgingwilloccurconsistofclastics,rangingfromboulderstocoarsesandandsilt(Harza/EbascoSusitnaJointVenture1983).Thefractionofthegravel-sandmaterialsinthesilt-claysizecategory[<0.0025in«63~m}Jwasapproximately5%ofthetotalbyweight.Assumingthat~1)thespecific?ravityofthematerialtobedredgedaverages0.0641b/in3(1.77g/cm),(2)6.54x10yd3(50x106m3)ofmaterialwouldbedredgedfromtheriverduringthesummersofthe6-yearconstructionperiod(ExhibitE),(3)5%ofthetotalweightofmaterialtobedredgedislosttoentrainmentinriverwater,and(4)thismaterialremainsinsuspension,thecalculatedincreaseinsuspendedsolidsatGoldCreekduringsummerisapproximately140ppm(mg/L).Thiscalculatedincreaseinsuspendedsolidsismostlikelyanoverestimatebecauseitisunlikelythatallofthematerialinthesilt-claysizerangewouldbeentrained,andnotallofthematerialthatisentrainedwouldremaininsuspensionasitistransporteddownstream.Inaddition,thefractionofmaterialthatisactuallyentrainedduringdredgingwouldmostlikelybelessthan5%ofthetotalweight.Forthesereasons,thepredictedincreaseinsuspendedsolidsatGoldCreekduetodredgingfortheconstructionofWatanaDamisconsideredtobeaconservativeoverestimate.InasmuchasdredgingwithintheSusitnaRiverfortheSusitnaprojectwouldoccurprimarilyduringtheconstructionofWatanaDam,themajorchangesinsuspendedsolidsresultingfromexcavationofborrowmaterialswouldoccurduringtheconstructionofWatanaDam.TheclearingofvegetationanddisposalofspoilmaterialswithintheareatobeimpoundedbyWatanaDamwouldresultindisturbancesofsoilcoverandthesubsequenterosionofsomespoilmaterialsintotheSusitnaRiver.ThemagnitudeofincreasesinsuspendedsolidsintheriverresultingfromthesedisturbancesofsoilcovercannotbepredictedbecauseoftnelackofinformationonsoilerosionratesindisturbedareasintheupperSusitnaBasinthatareunderlainbydiscontinuouspermafrost.Itisanticipatedthatimpactsonsuspendedsolidsresultingfromvegetationclearingwouldbeminimal;however,becauseerosionfromsuchdisturbedareaswouldoccurprimarilyduringspringbreakupandsummer,theperiodwhensuspendedsolidsintheSusitnaRiverareattheirannualmaximumconcentration.Inaddition,theapplicanthasproposedusingmitigativemeasurestominimizetheimpactofvegetationclearingonwaterquality(Sec.2.1.8).Asthereservoirbeginstofill,WatanawouldacteitherasasourceorasinkforsuspendedsolidsintheSusitnaRiver,dependingonthetimeofyear.Theabilityofareservoirtoretainsuspendedsediments,referredtoasthetrappingefficiency,isexpressedasthepercentageofinf10wingsedimentthatisretainedinthereservoirbasin.Trappingefficiencyvariesasafunctionof(1)inf10wingsedimentparticlesize,(2)thehydraulicflushingrate,ordetentionstoragetimeofwaterinthereservoir,(3)locationandoperationofthereservoiroutlet,(4)reservoirshape,(5)inducedmixingofreservoirwater,and(6)chemicalpropertiesofthewater.Detentionstoragetimeisprobablythesinglemostimportantfactordeterminingthetrappingefficiencyofareservoir.ThetrappingefficiencyofWatanaReservoirduringthefirstyearoffillingwaspredictedusingtheBrune(1953)curve,anempiricalrelationshipbetweenthetrappingefficiencyofreservoirsandtheirdetentionstoragetime.Thepredictedtrappingefficiencyrangesfromapproximately40%attheendofJunetoapproximately90%attheendofOctober.Thesepredictedreductionsare,however,consideredoverestimatesbyFERCstaffbecausetheBrunecurveisnotbasedondatafromreservoirsinwhichglacialflour,whichhasalowsettlingvelocity,dominatestheloadofinf10wingsuspendedsolids.Inaddition,waterreleasedfromWatanaduringthefirstyearoffillingwouldpassthroughthelow-leveloutlet.ThiswouldmostlikelyresultinalowertrappingefficiencythanthatpredictedbytheBrunecurvebecausesluicingoperationssuchasthistendtoreducethetrappingefficiencyrelativetothatincomparablereservoirswithsurfacedischarges(Brune1953).H-45H.5SURFACEWATERQUALITYH.5.1SalinityTheSusitnaRiverisamajorcontributoroffreshwatertoCookInlet,withthemeasuredflowatGoldCreekaccountingforapproximately19%ofthemeasuredflowatSusitnaStationnearCookInlet(ExhibitE,Chapter2).Assuch,theSusitnaRiverhasamajorinfluenceonthesalinityoftheupperCookInlet.Atnode27nearthemouthoftheSusitnaRiver(FigureH.5.1-1),salinityrangesannuallyfromapproximately6to21partsperthousand(ppt)(g/L)(FigureH.5.1-2).AsoneproceedsdownCookInlettowardtheGulfofAlaska,thesalinityincreases,approachingthatofseawater(FigureH.5.1-2),andtheannualvariationinsalinitydecreases,owingtothedeclininginfluenceoffreshwaterinputstoCookInlet.H.5.2SuspendedSolidsToassesstheeffectofdredgingforWatanaDamonsuspendedsedimentsintheSusitnaRiver,theincrementalincreaseinsuspendedsolidswascalculatedbyassumingthatacertainfractionofdredgedmaterialwouldbelosttoentrainmentinriverwater.ResultsofgeotechnicalsurveysconductedattheWatanaDamsiteindicatethatalluvialdepositsintheriverchannelupstreamofwheredredgingwilloccurconsistofclastics,rangingfromboulderstocoarsesandandsilt(Harza/EbascoSusitnaJointVenture1983).Thefractionofthegravel-sandmaterialsinthesilt-claysizecategory[<0.0025in«63~m}Jwasapproximately5%ofthetotalbyweight.Assumingthat~1)thespecific?ravityofthematerialtobedredgedaverages0.0641b/in3(1.77g/cm),(2)6.54x10yd3(50x106m3)ofmaterialwouldbedredgedfromtheriverduringthesummersofthe6-yearconstructionperiod(ExhibitE),(3)5%ofthetotalweightofmaterialtobedredgedislosttoentrainmentinriverwater,and(4)thismaterialremainsinsuspension,thecalculatedincreaseinsuspendedsolidsatGoldCreekduringsummerisapproximately140ppm(mg/L).Thiscalculatedincreaseinsuspendedsolidsismostlikelyanoverestimatebecauseitisunlikelythatallofthematerialinthesilt-claysizerangewouldbeentrained,andnotallofthematerialthatisentrainedwouldremaininsuspensionasitistransporteddownstream.Inaddition,thefractionofmaterialthatisactuallyentrainedduringdredgingwouldmostlikelybelessthan5%ofthetotalweight.Forthesereasons,thepredictedincreaseinsuspendedsolidsatGoldCreekduetodredgingfortheconstructionofWatanaDamisconsideredtobeaconservativeoverestimate.InasmuchasdredgingwithintheSusitnaRiverfortheSusitnaprojectwouldoccurprimarilyduringtheconstructionofWatanaDam,themajorchangesinsuspendedsolidsresultingfromexcavationofborrowmaterialswouldoccurduringtheconstructionofWatanaDam.TheclearingofvegetationanddisposalofspoilmaterialswithintheareatobeimpoundedbyWatanaDamwouldresultindisturbancesofsoilcoverandthesubsequenterosionofsomespoilmaterialsintotheSusitnaRiver.ThemagnitudeofincreasesinsuspendedsolidsintheriverresultingfromthesedisturbancesofsoilcovercannotbepredictedbecauseoftnelackofinformationonsoilerosionratesindisturbedareasintheupperSusitnaBasinthatareunderlainbydiscontinuouspermafrost.Itisanticipatedthatimpactsonsuspendedsolidsresultingfromvegetationclearingwouldbeminimal;however,becauseerosionfromsuchdisturbedareaswouldoccurprimarilyduringspringbreakupandsummer,theperiodwhensuspendedsolidsintheSusitnaRiverareattheirannualmaximumconcentration.Inaddition,theapplicanthasproposedusingmitigativemeasurestominimizetheimpactofvegetationclearingonwaterquality(Sec.2.1.8).Asthereservoirbeginstofill,WatanawouldacteitherasasourceorasinkforsuspendedsolidsintheSusitnaRiver,dependingonthetimeofyear.Theabilityofareservoirtoretainsuspendedsediments,referredtoasthetrappingefficiency,isexpressedasthepercentageofinf10wingsedimentthatisretainedinthereservoirbasin.Trappingefficiencyvariesasafunctionof(1)inf10wingsedimentparticlesize,(2)thehydraulicflushingrate,ordetentionstoragetimeofwaterinthereservoir,(3)locationandoperationofthereservoiroutlet,(4)reservoirshape,(5)inducedmixingofreservoirwater,and(6)chemicalpropertiesofthewater.Detentionstoragetimeisprobablythesinglemostimportantfactordeterminingthetrappingefficiencyofareservoir.ThetrappingefficiencyofWatanaReservoirduringthefirstyearoffillingwaspredictedusingtheBrune(1953)curve,anempiricalrelationshipbetweenthetrappingefficiencyofreservoirsandtheirdetentionstoragetime.Thepredictedtrappingefficiencyrangesfromapproximately40%attheendofJunetoapproximately90%attheendofOctober.Thesepredictedreductionsare,however,consideredoverestimatesbyFERCstaffbecausetheBrunecurveisnotbasedondatafromreservoirsinwhichglacialflour,whichhasalowsettlingvelocity,dominatestheloadofinf10wingsuspendedsolids.Inaddition,waterreleasedfromWatanaduringthefirstyearoffillingwouldpassthroughthelow-leveloutlet.ThiswouldmostlikelyresultinalowertrappingefficiencythanthatpredictedbytheBrunecurvebecausesluicingoperationssuchasthistendtoreducethetrappingefficiencyrelativetothatincomparablereservoirswithsurfacedischarges(Brune1953). 1 \ &SALINITY SAMPLING LOCATIONS &. NODE 1 BL YING SOUND miles o 10 20 30 40 50 I I I I I I o 16.09 48.28 80.47 kilometers ::I: I -Po 0'\ Figure H.5 -1.Locations of sampling stations for salinity in Cook Inlet (Exhibit E.Chapter 2). 1 \ &SALINITY SAMPLING LOCATIONS &. NODE 1 COOK INLET BL YING SOUND o I miles 10 20 30 I I I 16.09 48.28 kilometers 40 50 I I 80.47 Figure H.5 -1.Locations of sampling stations for salinity in Cook Inlet (Exhibit E.Chapter 2). 30 . NODE 1 I-01- ~25.. "0 C 0 ~20 0..c 01- .......... (J) 1:15 0a.I AODE 27 \I :r:-....I.p. >--..J I-10 z-...J«5(/) o I I I I I I I I I I I I I o N D J F M A MONTHS M J J A s Figure H.5-2.Seasonal pattern in the salinity of water in Cook Inlet at nodes 1,12,and 27.The location of the sampling stations (nodes)is illustrated in Figure H.5 -1 (Exhibit E, Table E.2.31). 30 NODE 1-01- ~25.. "0 C 0 (/)20::J 0..c 01- .......... (/) 01-15l... 0a.:r: I-.....p. -..J>-10I- Z-...J«5(/) o N D J F M A MONTHS M J J A s Figure H.5-2.Seasonal pattern in the salinity of water in Cook Inlet at nodes 1,12,and 27.The location of the sampling stations (nodes)is illustrated in Figure H.5 -1 (Exhibit E, Table E.2.31). H-48Duringthefirstwinteroffilling,theconcentrationofsuspendedsolidsattheoutletofWatanawouldexceedthatintheSusitnaRiverunderpreprojectconditions.Thisisaresultoftheoutflowofsuspendedsolidsretainedinthereservoirduringthefirstfillingperiod,JunetoOctober.Becauseofthesluicingoperationduringthefirstyearoffilling,theconcentrationofsuspendedsolidsattheoutletofWatanaduringwinterispredictedtoexceed50ppm(mg/L).Duringthesecondwinterofthefillingperiod,thetrappingefficiencyshouldapproximatethatofthefull-pool(operational)efficiencywhensuspendedsolidsinwinterarelessthan50ppm.DuringthefillingofWatana,additionalsuspendedsolidswouldbeintroducedintothereservoirduetoshoreerosionandlandslidesresultingfromslopeinstability.Thisinstabilityisaresultofthethawingofpermafrostasitissubmergedwithinthereservoir.Theeffectofshorelineslumpingandshorelineerosiononsuspendedsolidsinreservoirsisinfluencedbytheamountoffine-grained(silt,clay)particlesinsoilswithintheimpoundmentzone,waveaction,andtheageofthereservoir(Newburyetal.1978).Fine-grainedparticlesaremoreeasilyerodedand,onceentrained,wouldremaininsuspensionlongerbecauseoftheirlowersettlingvelocity.Asthesefine-grainedmaterialsareerodedfromtheshorelineandasbankslumpingdeclines,stableshorelineswoulddevelop,resultingislessentrainmentofsoilparticleswithintheimpoundmentzone.Informationontheamountoffine-grainedmaterialsinsoilsintheimpoundmentzoneofWatanawasnotavailable.Ifthesiltandclaycontentishigh,shorelineerosionandbankslumpingcouldresultinsignificantincreasesinsuspendedsolidsin,anddownstreamof,WatanaReservoir.ItisanticipatedthatthecontributionofbankerosionandbankslumpingtosuspendedsolidsinWatanaReservoirandintheSusitnaRiverdownstreamofthereservoirwouldbemaximalduringandimmediatelyafterfillingandwoulddeclineinimportancewhenstableshorelinesdevelopasthereservoirages.PredictingtnemagnitudeofsuspendedsolidsthatwouldbeaddedtoWatanaasaresultoftheseprocessesisnotpossible.Itisanticipated,however,thattheturbidityandsuspended-solidsconcentrationinWatanaReservoirandintheSusitnaRiverdownstreamofWatanaduringfillingwouldbecontrolledprimarilybyglacialscouringintheheadwatersoftheSusitnaRiverratherthanbybankslumping,slides,anderosionwithintheimpoundmentarea.ThenetincreaseinsuspendedsolidsintheSusitnaRiverdownstreamofWatanaduringoperationinwinterhasbeenestimatedbytheapplicant(ExhibitE,Chapter2),usingtheDEPOSITSmodel(Peratrovichetal.1982).Thismodeldescribesthesedimenttransportanddepositionprocessesinareservoirasafunctionofbasingeometry,theinflowhydrographforsedimentsandwater,sedimentcharacteristics,theoutletstructure,andthehydraulicbehaviorofflowwithinthereservoirbasin.Becausethemodeldoesnottakeintoaccountdispersive(longitudinal)mixingofinflowingsediments,andbecausethedeadstoragevolumeinthereservoirisdifficulttopredict,timevariationinsuspendedsolidsdischargedfromthedamcannotbeestimatedwiththemodel.Assumingthatthereservoirwouldbehaveasaplugflowsystembyignoringdispersivemixingimpliesthatthesuspendedsolidsleavingthereservoirduringwinter enteredthereservoirapproximately19monthsearlierinsummerwhensuspendedsolidsareattheirannualmaximum.Thus,ignoringdispersivemixingtendstoprovideaconservativeoverestimateofthewinterdischargesofsuspendedsolidsbecauseitassumesnodilutionofhighsedimentloadswithwatercontaininglowsedimentloadsthatwouldhavepreviouslyenteredthereservoirinwinter.Althoughreentrainmentofdepositedsedimentwouldtendtoincreasetheconcentrationinwinter,thisshouldbeminimal,sincethereservoirwouldbecoveredwithiceandwind-inducedmixinganderosionwouldthereforebeminimal.Underthesewinterconditions,thetrappingefficiencyofthereservoirispredictedbytheapplicanttobeintherangeof94to96%,dependingontheassumeddeadstoragevolumeofthereservoir.ThetrappingefficiencyforWatanaReservoirinsummer,asestimatedusingtheDEPOSITSmodel(Peratrovicheta1.1982),rangesfrom78to90%,dependingontheassumeddeadstoragevolumeinthereservoir.UsingtheaverageconcentrationofsuspendedsolidsatVeeCanyoninsummerastheinput,thecalculatedconcentrationattheoutletofWatanaduringsummerwouldrangefrom80to176ppm(mg/L)(TableH.5.2-1).Aspreviouslydiscussed,theeffectofignoringdispersivemixingofsuspendedsolidsenteringWatana.Reservoirwouldbetoconservativelyoverestimatetheconcentrationattheoutlet.However,thiscalculationalsoignoresinternallygeneratedsourcesofsuspendedsolidsfromshoreerosion,bankslumping,andresuspension.Themagnitudeofthesesourcescannotbepredicted,buttheycouldbesignificant,particularlyduringandimmediatelyafterfillingwhenbankslumpingandshoreerosionarelikelytobeatamaximum.Theeffectofreentrainmentofsedimentsonthereservoirbottomduetowindmixing,shoreerosion,andbankslumpingwouldtendtoincreasetheconcentrationattheoutletrelativetotnatpredictedbythemodel.Reentrainmentislikelytobeminimal,however,becausemostsedimentationwouldoccurintheupstreamendofthereservoir.WiththelongdetentionstoragetimeofwaterinWatana,mostoftheresuspendedsedimentswouldsettleoutofthewatercolumnduringquiescentperiodsbeforereachingthedam.H-48Duringthefirstwinteroffilling,theconcentrationofsuspendedsolidsattheoutletofWatanawouldexceedthatintheSusitnaRiverunderpreprojectconditions.Thisisaresultoftheoutflowofsuspendedsolidsretainedinthereservoirduringthefirstfillingperiod,JunetoOctober.Becauseofthesluicingoperationduringthefirstyearoffilling,theconcentrationofsuspendedsolidsattheoutletofWatanaduringwinterispredictedtoexceed50ppm(mg/L).Duringthesecondwinterofthefillingperiod,thetrappingefficiencyshouldapproximatethatofthefull-pool(operational)efficiencywhensuspendedsolidsinwinterarelessthan50ppm.DuringthefillingofWatana,additionalsuspendedsolidswouldbeintroducedintothereservoirduetoshoreerosionandlandslidesresultingfromslopeinstability.Thisinstabilityisaresultofthethawingofpermafrostasitissubmergedwithinthereservoir.Theeffectofshorelineslumpingandshorelineerosiononsuspendedsolidsinreservoirsisinfluencedbytheamountoffine-grained(silt,clay)particlesinsoilswithintheimpoundmentzone,waveaction,andtheageofthereservoir(Newburyetal.1978).Fine-grainedparticlesaremoreeasilyerodedand,onceentrained,wouldremaininsuspensionlongerbecauseoftheirlowersettlingvelocity.Asthesefine-grainedmaterialsareerodedfromtheshorelineandasbankslumpingdeclines,stableshorelineswoulddevelop,resultingislessentrainmentofsoilparticleswithintheimpoundmentzone.Informationontheamountoffine-grainedmaterialsinsoilsintheimpoundmentzoneofWatanawasnotavailable.Ifthesiltandclaycontentishigh,shorelineerosionandbankslumpingcouldresultinsignificantincreasesinsuspendedsolidsin,anddownstreamof,WatanaReservoir.ItisanticipatedthatthecontributionofbankerosionandbankslumpingtosuspendedsolidsinWatanaReservoirandintheSusitnaRiverdownstreamofthereservoirwouldbemaximalduringandimmediatelyafterfillingandwoulddeclineinimportancewhenstableshorelinesdevelopasthereservoirages.PredictingtnemagnitudeofsuspendedsolidsthatwouldbeaddedtoWatanaasaresultoftheseprocessesisnotpossible.Itisanticipated,however,thattheturbidityandsuspended-solidsconcentrationinWatanaReservoirandintheSusitnaRiverdownstreamofWatanaduringfillingwouldbecontrolledprimarilybyglacialscouringintheheadwatersoftheSusitnaRiverratherthanbybankslumping,slides,anderosionwithintheimpoundmentarea.ThenetincreaseinsuspendedsolidsintheSusitnaRiverdownstreamofWatanaduringoperationinwinterhasbeenestimatedbytheapplicant(ExhibitE,Chapter2),usingtheDEPOSITSmodel(Peratrovichetal.1982).Thismodeldescribesthesedimenttransportanddepositionprocessesinareservoirasafunctionofbasingeometry,theinflowhydrographforsedimentsandwater,sedimentcharacteristics,theoutletstructure,andthehydraulicbehaviorofflowwithinthereservoirbasin.Becausethemodeldoesnottakeintoaccountdispersive(longitudinal)mixingofinflowingsediments,andbecausethedeadstoragevolumeinthereservoirisdifficulttopredict,timevariationinsuspendedsolidsdischargedfromthedamcannotbeestimatedwiththemodel.Assumingthatthereservoirwouldbehaveasaplugflowsystembyignoringdispersivemixingimpliesthatthesuspendedsolidsleavingthereservoirduringwinter enteredthereservoirapproximately19monthsearlierinsummerwhensuspendedsolidsareattheirannualmaximum.Thus,ignoringdispersivemixingtendstoprovideaconservativeoverestimateofthewinterdischargesofsuspendedsolidsbecauseitassumesnodilutionofhighsedimentloadswithwatercontaininglowsedimentloadsthatwouldhavepreviouslyenteredthereservoirinwinter.Althoughreentrainmentofdepositedsedimentwouldtendtoincreasetheconcentrationinwinter,thisshouldbeminimal,sincethereservoirwouldbecoveredwithiceandwind-inducedmixinganderosionwouldthereforebeminimal.Underthesewinterconditions,thetrappingefficiencyofthereservoirispredictedbytheapplicanttobeintherangeof94to96%,dependingontheassumeddeadstoragevolumeofthereservoir.ThetrappingefficiencyforWatanaReservoirinsummer,asestimatedusingtheDEPOSITSmodel(Peratrovicheta1.1982),rangesfrom78to90%,dependingontheassumeddeadstoragevolumeinthereservoir.UsingtheaverageconcentrationofsuspendedsolidsatVeeCanyoninsummerastheinput,thecalculatedconcentrationattheoutletofWatanaduringsummerwouldrangefrom80to176ppm(mg/L)(TableH.5.2-1).Aspreviouslydiscussed,theeffectofignoringdispersivemixingofsuspendedsolidsenteringWatana.Reservoirwouldbetoconservativelyoverestimatetheconcentrationattheoutlet.However,thiscalculationalsoignoresinternallygeneratedsourcesofsuspendedsolidsfromshoreerosion,bankslumping,andresuspension.Themagnitudeofthesesourcescannotbepredicted,buttheycouldbesignificant,particularlyduringandimmediatelyafterfillingwhenbankslumpingandshoreerosionarelikelytobeatamaximum.Theeffectofreentrainmentofsedimentsonthereservoirbottomduetowindmixing,shoreerosion,andbankslumpingwouldtendtoincreasetheconcentrationattheoutletrelativetotnatpredictedbythemodel.Reentrainmentislikelytobeminimal,however,becausemostsedimentationwouldoccurintheupstreamendofthereservoir.WiththelongdetentionstoragetimeofwaterinWatana,mostoftheresuspendedsedimentswouldsettleoutofthewatercolumnduringquiescentperiodsbeforereachingthedam. H-49TableH.5-1.Maximum,Minimum,andAveragePreprojectConcentrationofSuspendedSolidsintheSusitnaRiveratGoldCreekinWinterandSummer,andtheCalculatedPostprojectConcentrationwithWatanainOperation.tSuspendedSolids(ppm)t2PreprojectPostprojectSeasonMaximumt3Minimumt3Averaget3(WatanaAlone)Winter7611232t4_50t5Summer2620774080t4-176t5tlPostprojectvalueswerecalculatedusingtrappingefficienciesderivedfromtheDEPOSITSmodel(Peratrovichetal.1982).Rangesarebasedonassumedrangeofdeadstoragevolumes.Themaximumvalueisforadeadstoragevolumeequaltoapproximately10%ofthetotal(liveplusdead)storagevolume.Theminimumvalueisforadeadstoragevolumeequaltotheaveragedifferencebetweentotalandlivestoragevolumes(Peratrovichetal.1982).t21ppm- 1mg/L.t3U.S.GeologicalSurveyWaterQualityAnnualReportforAlaska(USGS1982).Averagesfortheperiod,1949-1982.t4Assumesdeadstoragevolumeof900,000acre-ft(1.11x109m3)(i.e.,storagetimeofwater=(totalvolume-deadstoragevolume)/annnualinflow).t5Assumesentirevolumebelow2050ft(625m)inWatanaisdeadstorage.ThereliabilityofapredictedrangeofsuspendedsolidsattheoutletofWatanaReservoirinsummercanbeevaluatedbycomparingitwithmeasuredconcentrationsofsuspendedsolidsinanexistingAlaskanreservoirthatshouldhaveatrappingefficiencycomparabletothatpredictedforWatana.LakeEklutna,areservoirlocatedinsouth-centralAlaska,hasacalculatedhydraulicflushingrateof646dayscomparedto635daysforWatana.TheloadofsuspendedsolidsenteringLakeEklutnaisalsodominatedbyglacialflourandthusshouldbecomparabletoWatanaintermsofthesettlingcharacteristicsofsuspended-solids.TheestimatedsuspendedsolidsconcentrationattheoutletofLakeEklutnainsummer,asestimatedfrommeasuredturbidity,whichisthenconvertedtosuspended-solidsconcentrationusinganempiricallyderivedregressionequationforturbidityandsuspendedsolidsintheSusitnaRiver(Peratrovichetal.1982),rangesfrom110to220ppm(mg/L).Thiscomparestothepredictedrangeof80to176ppmattheoutletofWatanainsummer,usingtheminimumandmaximumestimatedtrappingefficiencyfromtheDEPOSITSmodel(TableH.5.2-1).Thesimilarityinthemeasuredandpredictedconcentrationsofthesetworeservoirs,whichareexpectedtoexhibitsimilartrappingefficiencies,tendstosupportthepredictedvaluesforsuspendedsolidsattheoutletofWatanaReservoir.H.5.3NitrogenGasSaturationInordertomaintaintherequireddownstreamflowof12,000ft3/s(340m3/s)intheSusitnaRiverduringAugustandSeptember,flowaugmentationofpowerhouse(turbine)dischargesatWatanawouldberequired.Thisflowaugmentationwouldinvolvereleasingwaterthroughtheoutletfacility.Becauseoftheheightofthedam,releasesfromtheoutletfacilitywillhavealargehydrostatichead.Theenergyinthislargehydrostaticheadwouldbedissipatedbyinstallingfixedconevalvesatthedownstreamendoftheoutletfacility.Theexactlevelofsupersaturationbelowthedamcannotbepredictedwithavailableinformationbutwouldbeinfluencedbythelevelofsaturationofwaterleavingthereservoirandtheamountofairentrainedinwaterreleasedfromtheoutletfacility.Levelsofnitrogensaturationduringspillwaydischargesthatexceed130%arenotuncommonbelowsomelargedamsontheColumbiaandSnakeriverswithhydrostaticheadslessthanthatwhichwouldexistatWatana(Ebe11971;Blahmetal.1976).Thus,withoutthefixedconevalves,nitrogensaturationlevelsof130%andgreaterwouldbeexpectedduringoutletflowsatWatana.Iftheconevalvesarenoteffectiveinreducingthehydraulicmomentum,dilutingtheexcessflowsbymixingthemwithH-49TableH.5-1.Maximum,Minimum,andAveragePreprojectConcentrationofSuspendedSolidsintheSusitnaRiveratGoldCreekinWinterandSummer,andtheCalculatedPostprojectConcentrationwithWatanainOperation.tSuspendedSolids(ppm)t2PreprojectPostprojectSeasonMaximumt3Minimumt3Averaget3(WatanaAlone)Winter7611232t4_50t5Summer2620774080t4-176t5tlPostprojectvalueswerecalculatedusingtrappingefficienciesderivedfromtheDEPOSITSmodel(Peratrovichetal.1982).Rangesarebasedonassumedrangeofdeadstoragevolumes.Themaximumvalueisforadeadstoragevolumeequaltoapproximately10%ofthetotal(liveplusdead)storagevolume.Theminimumvalueisforadeadstoragevolumeequaltotheaveragedifferencebetweentotalandlivestoragevolumes(Peratrovichetal.1982).t21ppm-1mg/L.t3U.S.GeologicalSurveyWaterQualityAnnualReportforAlaska(USGS1982).Averagesfortheperiod,1949-1982.t4Assumesdeadstoragevolumeof900,000acre-ft(1.11x109m3)(i.e.,storagetimeofwater=(totalvolume-deadstoragevolume)/annnualinflow).t5Assumesentirevolumebelow2050ft(625m)inWatanaisdeadstorage.ThereliabilityofapredictedrangeofsuspendedsolidsattheoutletofWatanaReservoirinsummercanbeevaluatedbycomparingitwithmeasuredconcentrationsofsuspendedsolidsinanexistingAlaskanreservoirthatshouldhaveatrappingefficiencycomparabletothatpredictedforWatana.LakeEklutna,areservoirlocatedinsouth-centralAlaska,hasacalculatedhydraulicflushingrateof646dayscomparedto635daysforWatana.TheloadofsuspendedsolidsenteringLakeEklutnaisalsodominatedbyglacialflourandthusshouldbecomparabletoWatanaintermsofthesettlingcharacteristicsofsuspended-solids.TheestimatedsuspendedsolidsconcentrationattheoutletofLakeEklutnainsummer,asestimatedfrommeasuredturbidity,whichisthenconvertedtosuspended-solidsconcentrationusinganempiricallyderivedregressionequationforturbidityandsuspendedsolidsintheSusitnaRiver(Peratrovichetal.1982),rangesfrom110to220ppm(mg/L).Thiscomparestothepredictedrangeof80to176ppmattheoutletofWatanainsummer,usingtheminimumandmaximumestimatedtrappingefficiencyfromtheDEPOSITSmodel(TableH.5.2-1).Thesimilarityinthemeasuredandpredictedconcentrationsofthesetworeservoirs,whichareexpectedtoexhibitsimilartrappingefficiencies,tendstosupportthepredictedvaluesforsuspendedsolidsattheoutletofWatanaReservoir.H.5.3NitrogenGasSaturationInordertomaintaintherequireddownstreamflowof12,000ft3/s(340m3/s)intheSusitnaRiverduringAugustandSeptember,flowaugmentationofpowerhouse(turbine)dischargesatWatanawouldberequired.Thisflowaugmentationwouldinvolvereleasingwaterthroughtheoutletfacility.Becauseoftheheightofthedam,releasesfromtheoutletfacilitywillhavealargehydrostatichead.Theenergyinthislargehydrostaticheadwouldbedissipatedbyinstallingfixedconevalvesatthedownstreamendoftheoutletfacility.Theexactlevelofsupersaturationbelowthedamcannotbepredictedwithavailableinformationbutwouldbeinfluencedbythelevelofsaturationofwaterleavingthereservoirandtheamountofairentrainedinwaterreleasedfromtheoutletfacility.Levelsofnitrogensaturationduringspillwaydischargesthatexceed130%arenotuncommonbelowsomelargedamsontheColumbiaandSnakeriverswithhydrostaticheadslessthanthatwhichwouldexistatWatana(Ebe11971;Blahmetal.1976).Thus,withoutthefixedconevalves,nitrogensaturationlevelsof130%andgreaterwouldbeexpectedduringoutletflowsatWatana.Iftheconevalvesarenoteffectiveinreducingthehydraulicmomentum,dilutingtheexcessflowsbymixingthemwith H-50turbineflowsshouldreducethelevelofnitrogensupersaturationtolessthantheAlaskaDepartmentofEnvironmentalConservation(ADEC)statuteof110%,providedthat(1)thelevelofsaturationinaugmentationflowsdoesnotexceed140%ofsaturation,(2)thelevelofsaturationinturbineflowsisatoraboutsaturation,and(3)rapidmixingofoutletandturbineflowsoccursdownstreamofthedam.AugmentationflowsatWatanawouldberequiredinalmosteveryyearduringAugustandSeptember,basedonthe1995energy-demandscenario(ExhibitE,TableE.2.50).Sinceaugmentationflowswouldalmostcertainlybesupersaturatedwithnitrogentoalevelgreaterthan110%iftheconevalveswereineffectiveinpreventingairentrainment,reducingthesaturationleveltolessthantheADECstatuteimmediatelybelowthedamwoulddependprimarilyontherateofmixing.Thisisbecausediffusionacrosstheair-waterinterfaceincreaseswithturbulentmixingandmixingdecreaseswithincreasingflowintheSusitnaRiver(Peratrovichetal.1983).Thus,althoughthelevelofnitrogensupersaturationwoulddecreaseexponentiallywithdistancefromdiffusionalonedownstreamofthedamintheabsenceofmixingwithturbineflows,saturationlevelsinexcessof110%wouldexistfortensofmilesdownstream.Theexactdistanceofthesupersaturationwoulddependonthenitrogensaturationlevelimmediatelybelowthedamandthedecayrate(i.e.,rateofsupersaturationdecay)forgaseousnitrogenasafunctionofdistancedownstreamofWatana.Ifmixingofaugmentationandturbineflowsisslow,aplumeofwatercontaininggaseousnitrogeninexcessoftheADECstatutewouldexistdownstreamofWatanaduringaugmentationflowsinAugustandSeptemberofalmosteveryyearofoperationwiththe1995energy-demand.Withtheenergy-demandscenariofortheyear2000,turbinedischargewouldincrease,thusreducingtheneedforaugmentationflowsand,inturn,reducingnitrogensupersaturation.DuringexcessflowsthatarerequiredtomaintainthenormalmaximumoperatinglevelofWatanaat2185ft(666m),waterwouldbereleasedfromtheoutletfacility.Becauseofthegreatervolumeofexcessflows(ExhibitE,TableE.2.50),dilutionwithturbineflowsalonewouldbeinsufficienttoreducethelevelofnitrogensupersaturationtolessthantheADECstatuteimmediatelydownstreamofthedamifthefixedconevalveswereineffective.Asaresult,nitrogensupersaturationinexcessof110%wouldoccurforseveralmilesdownstreamofWatanaduringexcessflows,resultinginsignificantdegradationofwaterqualityforaquaticlife,particularlyfishandbenthicinvertebrates.Basedonthe1995energysimulation(ExhibitE,TableE.2.50)andusinga30-yearsimulationperiodofflowsintheSusitnaRiver,excessflowsthatwouldmostlikelyresultinnitrogensupersaturationgreaterthantheADECstatutehaveaprobabilityofoccurrenceof23%,occurringseventimesina30-yearperiod.TheproposedmitigativestrategyofsimulatingpeakflowsintheSusitnaRiverbyreleasingwaterthroughtheoutletfacilitywouldalsocausenitrogensupersaturationinexcessoftheADECstatuteiftheconevalvesdidnotpreventairentrainment,resultinginsignificantdegradationofwaterqualityforaquaticlife.H.5.4NutrientsReportedconcentrationsofinorganicnitrogenandphosphorusintheSusitnaRiveratVeeCanyonandthecomputedmolarnitrogen:phosphorusratioinriverwaterof10:1insummerandinexcessof20:1inwinter(R&MConsultants1982)suggestthatphosphorusistheelementmostlikelytolimitprimaryproductionintheriverduringwinter,whilebothnitrogenandphosphorusmaybelimitingduringsummer(Smith1982).Underpreproject conditions,however,primaryproductionintheSusitnaRiverismostlikelylimitedmorebysuspendedsediments,whichlimitlightpenetrationandscoursubstrates,thanbynutrients.Whilethetrappingofsuspendedsolidsbythereservoirswouldimproveconditionsforprimaryproductiondownriverinthesummer,theconcentrationofsuspendedsolidswouldstillremainatlevelsthatrestrictlightpenetration,therebylimitingprimaryproduction.Thetrophicstatusofclear-waterreservoirsandlakeshasbeenassessed,usingthenutrientloadingratesandthehydraulicflushingrates(Petersonetal.1982).Inthecaseofturbidlakes,suchastheproposedWatanaandDevilCanyonreservoirs,theresponseofphytoplanktontonutrientinputsislesscertainbecauseofbothlightlimitation,duetothehighturbidity,andtheeffects(adsorption-desorption)ofnonalgalsolidsonavailablenutrientsuppliesinwater(Smith1982).AnassessmentbasedonthespringconcentrationsofphosphorusinWatana,ascomputedfromthephosphorusconcentrationsatVeeCanyoninJune,suggeststhatWatanawouldbeoligotrophic(Petersonetal.1982).Assumingthatsuspendedsedimentswouldnotbeasourceofnutrientsforphytoplankton,thispredictedtrophicresponseofWatanatotheestimatedphosphorusloadingisaconservativeoverestimatebecauseitneglectstheeffect,onprimaryproductionratesofphytoplankton,oflowlightpenetrationduetothehighconcentrationofsuspendedsolidsinreservoirwater.H-50turbineflowsshouldreducethelevelofnitrogensupersaturationtolessthantheAlaskaDepartmentofEnvironmentalConservation(ADEC)statuteof110%,providedthat(1)thelevelofsaturationinaugmentationflowsdoesnotexceed140%ofsaturation,(2)thelevelofsaturationinturbineflowsisatoraboutsaturation,and(3)rapidmixingofoutletandturbineflowsoccursdownstreamofthedam.AugmentationflowsatWatanawouldberequiredinalmosteveryyearduringAugustandSeptember,basedonthe1995energy-demandscenario(ExhibitE,TableE.2.50).Sinceaugmentationflowswouldalmostcertainlybesupersaturatedwithnitrogentoalevelgreaterthan110%iftheconevalveswereineffectiveinpreventingairentrainment,reducingthesaturationleveltolessthantheADECstatuteimmediatelybelowthedamwoulddependprimarilyontherateofmixing.Thisisbecausediffusionacrosstheair-waterinterfaceincreaseswithturbulentmixingandmixingdecreaseswithincreasingflowintheSusitnaRiver(Peratrovichetal.1983).Thus,althoughthelevelofnitrogensupersaturationwoulddecreaseexponentiallywithdistancefromdiffusionalonedownstreamofthedamintheabsenceofmixingwithturbineflows,saturationlevelsinexcessof110%wouldexistfortensofmilesdownstream.Theexactdistanceofthesupersaturationwoulddependonthenitrogensaturationlevelimmediatelybelowthedamandthedecayrate(i.e.,rateofsupersaturationdecay)forgaseousnitrogenasafunctionofdistancedownstreamofWatana.Ifmixingofaugmentationandturbineflowsisslow,aplumeofwatercontaininggaseousnitrogeninexcessoftheADECstatutewouldexistdownstreamofWatanaduringaugmentationflowsinAugustandSeptemberofalmosteveryyearofoperationwiththe1995energy-demand.Withtheenergy-demandscenariofortheyear2000,turbinedischargewouldincrease,thusreducingtheneedforaugmentationflowsand,inturn,reducingnitrogensupersaturation.DuringexcessflowsthatarerequiredtomaintainthenormalmaximumoperatinglevelofWatanaat2185ft(666m),waterwouldbereleasedfromtheoutletfacility.Becauseofthegreatervolumeofexcessflows(ExhibitE,TableE.2.50),dilutionwithturbineflowsalonewouldbeinsufficienttoreducethelevelofnitrogensupersaturationtolessthantheADECstatuteimmediatelydownstreamofthedamifthefixedconevalveswereineffective.Asaresult,nitrogensupersaturationinexcessof110%wouldoccurforseveralmilesdownstreamofWatanaduringexcessflows,resultinginsignificantdegradationofwaterqualityforaquaticlife,particularlyfishandbenthicinvertebrates.Basedonthe1995energysimulation(ExhibitE,TableE.2.50)andusinga30-yearsimulationperiodofflowsintheSusitnaRiver,excessflowsthatwouldmostlikelyresultinnitrogensupersaturationgreaterthantheADECstatutehaveaprobabilityofoccurrenceof23%,occurringseventimesina30-yearperiod.TheproposedmitigativestrategyofsimulatingpeakflowsintheSusitnaRiverbyreleasingwaterthroughtheoutletfacilitywouldalsocausenitrogensupersaturationinexcessoftheADECstatuteiftheconevalvesdidnotpreventairentrainment,resultinginsignificantdegradationofwaterqualityforaquaticlife.H.5.4NutrientsReportedconcentrationsofinorganicnitrogenandphosphorusintheSusitnaRiveratVeeCanyonandthecomputedmolarnitrogen:phosphorusratioinriverwaterof10:1insummerandinexcessof20:1inwinter(R&MConsultants1982)suggestthatphosphorusistheelementmostlikelytolimitprimaryproductionintheriverduringwinter,whilebothnitrogenandphosphorusmaybelimitingduringsummer(Smith1982).Underpreproject conditions,however,primaryproductionintheSusitnaRiverismostlikelylimitedmorebysuspendedsediments,whichlimitlightpenetrationandscoursubstrates,thanbynutrients.Whilethetrappingofsuspendedsolidsbythereservoirswouldimproveconditionsforprimaryproductiondownriverinthesummer,theconcentrationofsuspendedsolidswouldstillremainatlevelsthatrestrictlightpenetration,therebylimitingprimaryproduction.Thetrophicstatusofclear-waterreservoirsandlakeshasbeenassessed,usingthenutrientloadingratesandthehydraulicflushingrates(Petersonetal.1982).Inthecaseofturbidlakes,suchastheproposedWatanaandDevilCanyonreservoirs,theresponseofphytoplanktontonutrientinputsislesscertainbecauseofbothlightlimitation,duetothehighturbidity,andtheeffects(adsorption-desorption)ofnonalgalsolidsonavailablenutrientsuppliesinwater(Smith1982).AnassessmentbasedonthespringconcentrationsofphosphorusinWatana,ascomputedfromthephosphorusconcentrationsatVeeCanyoninJune,suggeststhatWatanawouldbeoligotrophic(Petersonetal.1982).Assumingthatsuspendedsedimentswouldnotbeasourceofnutrientsforphytoplankton,thispredictedtrophicresponseofWatanatotheestimatedphosphorusloadingisaconservativeoverestimatebecauseitneglectstheeffect,onprimaryproductionratesofphytoplankton,oflowlightpenetrationduetothehighconcentrationofsuspendedsolidsinreservoirwater. H-51REFERENCESFORAPPENDIXHAlaskaDepartmentofFishandGame(ADFG).1982.SusitnaHydroelectricProject,FinalDraftReport,AquaticStudiesProgram.AcresAmerican,Inc.,Buffalo,NY.AlaskaDepartmentofFishandGame(ADFG).1983.SusitnaHydroAquaticStudiesPhaseIIReport,Synopsisofthe1982AquaticStudiesandAnalysisofFishandHabitatRelationships.AlaskaDepartmentofFishandGame,SusitnaHydroAquaticStudies,Anchorage,AK.Blahm,T.H.,B.McConnell,andG.R.Snyder.1976.GasSupersaturationResearch,NationalMarineFisheriesService,PrescottFacility-1971to1974,pp.11-19.~D.H.FickeisenandM.J.Schneider(eds.),GasBubbleDisease.CONF-741033.Tech.Info.Center,U.S.EnergyResearchandDevelopmentAdministration,OakRidge,TN.Brune,G.M.1953.Trapefficiencyofreservoirs.Trans.Am.Geophys.Union34:407-418.Ebel,W.J.1971.DissolvedNitrogenConcentrationsintheColumbiaandSnakeRiversin1970andTheirEffectonChinookSalmonandSteelheadTrout.NOAATech.ReportNMFSSSRF-646,U.S.Dept.ofCommerce,SuperintendentofDocuments,Washington,DC.Eraslan,A.H.1983.ESTONE:AComputerCodeforSimulatingFastTransient,One-DimensionalHydrodynamic,Thermal,andSalinityConditionsinControlledRiversandTidalEstuariesfortheAssessmentoftheAggregatedImpactofMultiplePowerPlant,Operation,NUREG/CR-2621.Gatto,L.W.,C.J.Merry,H.L.McKim,andD.E.Lawson.1980.EnvironmentalAnalysisoftheUpperSusitnaRiverBasinUsingLandsatImagery.CRRELReportNo.80-4,U.S.ArmyCorpsofEngineers,ColdRegionsResearchandEngineeringLaboratory,Hanover,NH.Harza/EbascoSusitnaJointVenture.1983.SusitnaHydroelectricProject,WatanaDevelopment,Winter1983GeotechnicalExporationProject,Vols.IandII.AlaskaPowerAuthority,Anchorage,AK.Newbury,R.W.,K.G.Beaty,andG.K.McCullough.1978.InitialShorelineErosioninaPermafrostAffectedReservoir,SouthernIndianLake,Canada,pp.834-839.InProceedings,ThirdInternationalConferenceonPermafrost,July10-13,1978:-Edmonton,Alberta,Vol.I.NationalResearchCouncilCanada,Ottawa,CanadaPeratrovich,Nottingham,andDrage,Inc.,andI.P.G.Hutchison.1982.SusitnaRiverSedimentationandWaterClarityStudy.AcresAmerican,Inc.,Anchorage,AK.Peratrovich,Nottingham,andDrage,Inc.1983.SusitnaHydroelectricProjectNitrogenSupersaturationStudy.AcresAmerican,Inc.,Anchorage,AK.Peterson,L.A.,andAssociatesandR&MConsultants,Inc.1982.WaterQualityEffectsResultingfromImpoundmentoftheSusitnaRiver.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.,andL.A.Peterson&Associates.1982.Task3:Hydrology,WaterQualityInterpretation-1981.R&MConsultants,Inc.,Anchorage,AK.R&MConsultants,Inc.(R&M)andW.D.Harrison.1982.SusitnaHydroelectricProject,1982SusitnaBasinGlacierStudies.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.(R&M)andW.D.Harrison.1981.SusitnaHydroelectricProject,GlacierStudies.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.1982.SusitnaHydroelectricProject-RiverMorphology.R&MConsultants,Inc.(R&M).1982a.SusitnaHydroelectricProject,HydraulicandIceStudies.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.(R&M).1982b.SusitnaHydroelectricProject,RiverMorphology.AcresAmerican,Inc.,Buffalo,NY.Smith,V.H.1982.Thenitrogenandphosphorusdependenceofalgalbiomassinlakes:Anempiricalandtheoreticalanalysis.Limnol.Oceanogr.27:1101-1111.Sugden,D.E.andB.W.John.1976.GlaciersandLandscape,aGeomorphicologicalApproach.EdwardArnold(Publishers)Ltd.,London,England.H-51REFERENCESFORAPPENDIXHAlaskaDepartmentofFishandGame(ADFG).1982.SusitnaHydroelectricProject,FinalDraftReport,AquaticStudiesProgram.AcresAmerican,Inc.,Buffalo,NY.AlaskaDepartmentofFishandGame(ADFG).1983.SusitnaHydroAquaticStudiesPhaseIIReport,Synopsisofthe1982AquaticStudiesandAnalysisofFishandHabitatRelationships.AlaskaDepartmentofFishandGame,SusitnaHydroAquaticStudies,Anchorage,AK.Blahm,T.H.,B.McConnell,andG.R.Snyder.1976.GasSupersaturationResearch,NationalMarineFisheriesService,PrescottFacility-1971to1974,pp.11-19.~D.H.FickeisenandM.J.Schneider(eds.),GasBubbleDisease.CONF-741033.Tech.Info.Center,U.S.EnergyResearchandDevelopmentAdministration,OakRidge,TN.Brune,G.M.1953.Trapefficiencyofreservoirs.Trans.Am.Geophys.Union34:407-418.Ebel,W.J.1971.DissolvedNitrogenConcentrationsintheColumbiaandSnakeRiversin1970andTheirEffectonChinookSalmonandSteelheadTrout.NOAATech.ReportNMFSSSRF-646,U.S.Dept.ofCommerce,SuperintendentofDocuments,Washington,DC.Eraslan,A.H.1983.ESTONE:AComputerCodeforSimulatingFastTransient,One-DimensionalHydrodynamic,Thermal,andSalinityConditionsinControlledRiversandTidalEstuariesfortheAssessmentoftheAggregatedImpactofMultiplePowerPlant,Operation,NUREG/CR-2621.Gatto,L.W.,C.J.Merry,H.L.McKim,andD.E.Lawson.1980.EnvironmentalAnalysisoftheUpperSusitnaRiverBasinUsingLandsatImagery.CRRELReportNo.80-4,U.S.ArmyCorpsofEngineers,ColdRegionsResearchandEngineeringLaboratory,Hanover,NH.Harza/EbascoSusitnaJointVenture.1983.SusitnaHydroelectricProject,WatanaDevelopment,Winter1983GeotechnicalExporationProject,Vols.IandII.AlaskaPowerAuthority,Anchorage,AK.Newbury,R.W.,K.G.Beaty,andG.K.McCullough.1978.InitialShorelineErosioninaPermafrostAffectedReservoir,SouthernIndianLake,Canada,pp.834-839.InProceedings,ThirdInternationalConferenceonPermafrost,July10-13,1978:-Edmonton,Alberta,Vol.I.NationalResearchCouncilCanada,Ottawa,CanadaPeratrovich,Nottingham,andDrage,Inc.,andI.P.G.Hutchison.1982.SusitnaRiverSedimentationandWaterClarityStudy.AcresAmerican,Inc.,Anchorage,AK.Peratrovich,Nottingham,andDrage,Inc.1983.SusitnaHydroelectricProjectNitrogenSupersaturationStudy.AcresAmerican,Inc.,Anchorage,AK.Peterson,L.A.,andAssociatesandR&MConsultants,Inc.1982.WaterQualityEffectsResultingfromImpoundmentoftheSusitnaRiver.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.,andL.A.Peterson&Associates.1982.Task3:Hydrology,WaterQualityInterpretation-1981.R&MConsultants,Inc.,Anchorage,AK.R&MConsultants,Inc.(R&M)andW.D.Harrison.1982.SusitnaHydroelectricProject,1982SusitnaBasinGlacierStudies.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.(R&M)andW.D.Harrison.1981.SusitnaHydroelectricProject,GlacierStudies.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.1982.SusitnaHydroelectricProject-RiverMorphology.R&MConsultants,Inc.(R&M).1982a.SusitnaHydroelectricProject,HydraulicandIceStudies.AcresAmerican,Inc.,Buffalo,NY.R&MConsultants,Inc.(R&M).1982b.SusitnaHydroelectricProject,RiverMorphology.AcresAmerican,Inc.,Buffalo,NY.Smith,V.H.1982.Thenitrogenandphosphorusdependenceofalgalbiomassinlakes:Anempiricalandtheoreticalanalysis.Limnol.Oceanogr.27:1101-1111.Sugden,D.E.andB.W.John.1976.GlaciersandLandscape,aGeomorphicologicalApproach.EdwardArnold(Publishers)Ltd.,London,England. H-52TexasWaterDevelopmentBoard.1970.ACompletionReportonStochasticOptimizationandSimulationTechniquesforManagementofRegionalWaterResourceSystems,VolumelIB:FILLIN-lProgramDescription.Trihey,E.W.1982.PreliminaryAssessmentofSpawningSalmonAccesstoSideSloughHabitatAboveTalkeetna.AcresAmerican,Inc.,Buffalo,NY.U.S.GeologicalSurvey(USGS).1982.WaterQualityAnnualReportforAlaska.USGSWaterDataReport.NationalTechnicalInformationService,Springfield,VA.H-52TexasWaterDevelopmentBoard.1970.ACompletionReportonStochasticOptimizationandSimulationTechniquesforManagementofRegionalWaterResourceSystems,VolumelIB:FILLIN-lProgramDescription.Trihey,E.W.1982.PreliminaryAssessmentofSpawningSalmonAccesstoSideSloughHabitatAboveTalkeetna.AcresAmerican,Inc.,Buffalo,NY.U.S.GeologicalSurvey(USGS).1982.WaterQualityAnnualReportforAlaska.USGSWaterDataReport.NationalTechnicalInformationService,Springfield,VA. DRAFTENVIRONMENTALIMPACTSTATEMENTSUSITNAHYDROELECTRICPROJECT,FERCNO.7114APPENDIXIFISHERIESANDAQUATICRESOURCESPreparedbyCharlesC.CoutantandWebsterVanWinkle,Jr.OakRidgeNationalLaboratoryI-IdDRAFTENVIRONMENTALIMPACTSTATEMENTSUSITNAHYDROELECTRICPROJECT,FERCNO.7114APPENDIXIFISHERIESANDAQUATICRESOURCESPreparedbyCharlesC.CoutantandWebsterVanWinkle,Jr.OakRidgeNationalLaboratoryI-Id APPENDIXI.FISHERIESANDAQUATICRESOURCES1.1AFFECTEDENVIRONMENTTheSusitnaRiverfisheriesconstituteoneofthemajorexploitedresourcesoftheprojectenvirons.Thetextsection(3.1.4)brieflyintroducesthespeciesintheregion;theirimportancetocommercial.sport.andsubsistenceharvestsinupperCookInletandtheSusitnadrainage;andthehabitatstheyuseinfourmajorzones:(1)thepotentiallyinundatedzoneaboveDevilCanyon.(2)uplandareastobeaffectedbyaccessfacilitiesortransmissionlines.(3)theSusitnaRiverbetweenDevilCanyonandtheconfluenceoftheSusitna.Talkeetna.andChulitnarivers.and(4)theSusitnadownstreamofTalkeetna.Insection(4.1.4).thetextbrieflysummarizestheanticipatedimpactsoftheprojectontheexistingfisheryandaquaticresources.Thisappendixsection(1.1)providesadditionalbackgroundanddetailsothatexistingknowledgeabouttheaffectedspeciesandtheenvironstheyinhabitcanbeplacedinthecontextofprojectalterationsoftheenvironment.Section1.2providesdetailsoftheanalyticalprocessusedforestimatingimpacts.1.1.1PlantandInvertebrateCommunitiesTheSusitnaRiveranditstributariescontainsparcealgalcommunities.Thephytoplankton(drifting)andperiphyton(attached)communitiesarelimitedbysiltscour(mainstem).coldtemperatures.lowlevelsofnutrients.andrapidflowrates.Thereisbetterdevelopmentinbackwatersofsloughs.butquantitativestudyhasbeenlacking.Emergentvegetationandthesurroundingterrestrialenvironment(Sec.3.1.5.1)provideorganicmatterinputtoaprimarilyheterotrophicaquaticsystem.Zooplanktonconsistingofcopepodsandc1adoceransisfoundinsloughswhereabundanceissufficientlylargetoprovideanimportantfoodsourceforplankton-feedingsockeyesalmonjuvenilesinAugustandSeptember(ADF&G1983c).Fewzoop1anktersarefoundinrapidlyflowingtributariesorthemainstem.StreambottominvertebratesarealsosparceintheSusitnamainstem.althoughpopulationsofmayflies(Ephenenptera).trueflies(Diptera).stoneflies(P1ecoptera).caddisflies(Trichoptera).aquaticmites(Hydracarina).aquaticworms(Oligochaetes).andOstracodshavebeencollectedinsloughandtributaryhabitats(Table1.1-1).Alloftheseinvertebratesareimportantfoodsourcesforyoungsalmonandhavebeenquantifiedinfishstomachanalyses(Figure1.1-1).Populationcompositiondifferedamongsloughsandbetweenthetwotributariesexamined(FourthofJulyCreekandIndianRiver).1.1.2BiologyandHabitatSuitabilityRequirementsofFishSpeciesThissectionprovidesinformationonthebiologyandhabitatpreferencesofmajorspeciesintheprojectarea(Table1.1-2).Emphasisisplacedonlife-cycleinformationrelevanttodefiningimpactsintheSusitnadrainage(Sec.1.2).Habitatsuitabilitycriteriaforeachspeciesisstressedhere.whereashabitatavailabilityandfishabundanceingeographiclocationsoftheSusitnadrainagearediscussedinSec.1.1.3.Unlessspecificallyreferenced.informationisfromExhibitEoftheapplication.McClane(1965).orAlaskaDepartmentofFishandGamedatareports(ADF&G1981a-f.1983a-e).1.1.2.1PacificSalmon(Oncorhynchusspecies)TherearesixPacificsalmonspecies.fiveofwhichoccurinNorthAmericaandtheSusitnadrainage.Theyarethechinook.locallycalledking(Oncorhynchustshawytscha).cohoorsilver(0.~)sutch).sockeyeorred(Q.nerka).pink(Q.gorbuscha).andch~mor.dog(Q.ketaT.ThegenusasawholehasarangefromFormosatoSanDiego.Ca11fornla.StocksonthePacificcoastofNorthAmericahavediminished.especiallyinthesouthernpartoftheirrange.duetooverfishing.habitatdestruction.creationofbarrierstomigrationsuchasirrigationdiversionsandhydroelectricdams.andpollution.Althoughadultfishpassagefacilitiesareprovidedatmanydams.manyupriverstockshavebeenlost.Recentintroductionsgreatlyextendedthespecies'range.especiallytotheLaurentianGreatLakes.1-3APPENDIXI.FISHERIESANDAQUATICRESOURCES1.1AFFECTEDENVIRONMENTTheSusitnaRiverfisheriesconstituteoneofthemajorexploitedresourcesoftheprojectenvirons.Thetextsection(3.1.4)brieflyintroducesthespeciesintheregion;theirimportancetocommercial.sport.andsubsistenceharvestsinupperCookInletandtheSusitnadrainage;andthehabitatstheyuseinfourmajorzones:(1)thepotentiallyinundatedzoneaboveDevilCanyon.(2)uplandareastobeaffectedbyaccessfacilitiesortransmissionlines.(3)theSusitnaRiverbetweenDevilCanyonandtheconfluenceoftheSusitna.Talkeetna.andChulitnarivers.and(4)theSusitnadownstreamofTalkeetna.Insection(4.1.4).thetextbrieflysummarizestheanticipatedimpactsoftheprojectontheexistingfisheryandaquaticresources.Thisappendixsection(1.1)providesadditionalbackgroundanddetailsothatexistingknowledgeabouttheaffectedspeciesandtheenvironstheyinhabitcanbeplacedinthecontextofprojectalterationsoftheenvironment.Section1.2providesdetailsoftheanalyticalprocessusedforestimatingimpacts.1.1.1PlantandInvertebrateCommunitiesTheSusitnaRiveranditstributariescontainsparcealgalcommunities.Thephytoplankton(drifting)andperiphyton(attached)communitiesarelimitedbysiltscour(mainstem).coldtemperatures.lowlevelsofnutrients.andrapidflowrates.Thereisbetterdevelopmentinbackwatersofsloughs.butquantitativestudyhasbeenlacking.Emergentvegetationandthesurroundingterrestrialenvironment(Sec.3.1.5.1)provideorganicmatterinputtoaprimarilyheterotrophicaquaticsystem.Zooplanktonconsistingofcopepodsandc1adoceransisfoundinsloughswhereabundanceissufficientlylargetoprovideanimportantfoodsourceforplankton-feedingsockeyesalmonjuvenilesinAugustandSeptember(ADF&G1983c).Fewzoop1anktersarefoundinrapidlyflowingtributariesorthemainstem.StreambottominvertebratesarealsosparceintheSusitnamainstem.althoughpopulationsofmayflies(Ephenenptera).trueflies(Diptera).stoneflies(P1ecoptera).caddisflies(Trichoptera).aquaticmites(Hydracarina).aquaticworms(Oligochaetes).andOstracodshavebeencollectedinsloughandtributaryhabitats(Table1.1-1).Alloftheseinvertebratesareimportantfoodsourcesforyoungsalmonandhavebeenquantifiedinfishstomachanalyses(Figure1.1-1).Populationcompositiondifferedamongsloughsandbetweenthetwotributariesexamined(FourthofJulyCreekandIndianRiver).1.1.2BiologyandHabitatSuitabilityRequirementsofFishSpeciesThissectionprovidesinformationonthebiologyandhabitatpreferencesofmajorspeciesintheprojectarea(Table1.1-2).Emphasisisplacedonlife-cycleinformationrelevanttodefiningimpactsintheSusitnadrainage(Sec.1.2).Habitatsuitabilitycriteriaforeachspeciesisstressedhere.whereashabitatavailabilityandfishabundanceingeographiclocationsoftheSusitnadrainagearediscussedinSec.1.1.3.Unlessspecificallyreferenced.informationisfromExhibitEoftheapplication.McClane(1965).orAlaskaDepartmentofFishandGamedatareports(ADF&G1981a-f.1983a-e).1.1.2.1PacificSalmon(Oncorhynchusspecies)TherearesixPacificsalmonspecies.fiveofwhichoccurinNorthAmericaandtheSusitnadrainage.Theyarethechinook.locallycalledking(Oncorhynchustshawytscha).cohoorsilver(0.~)sutch).sockeyeorred(Q.nerka).pink(Q.gorbuscha).andch~mor.dog(Q.ketaT.ThegenusasawholehasarangefromFormosatoSanDiego.Ca11fornla.StocksonthePacificcoastofNorthAmericahavediminished.especiallyinthesouthernpartoftheirrange.duetooverfishing.habitatdestruction.creationofbarrierstomigrationsuchasirrigationdiversionsandhydroelectricdams.andpollution.Althoughadultfishpassagefacilitiesareprovidedatmanydams.manyupriverstockshavebeenlost.Recentintroductionsgreatlyextendedthespecies'range.especiallytotheLaurentianGreatLakes.1-3 1-4Tab1e1.1-1.InvertebrateTaxaPresentinDriftNet(D)andKickScreen(K)CollectionsfromallSitesSampledin1982(XIndicatesPresenceinBothCollectingTypes,0orKIndicatesOnlyOneType,0IndicatesAbsence)FourthSiteSloughSloughSloughSloughofJulyIndian8A112021CreekRiverOipteraChironomidaeXX XX XXEmpididaeXX0XKXPsychodidaeX0X00 0SimuliidaeX0XKXXTipulidaeK0KKXXEphemeropteraBaetidae00XKX XEphemerellidaeK 0K KXXHeptageniidae00XXX XSiphlonuridae0 0K 0X0PlecopteraCapniidaeX0XKXXChloroperlidaeX0KXKXNemouridae00XKX0PerlodidaeK0XK KXTaeneopterygidaeX000X0TrichopteraBrachycentridae0000X0Glossosomatidae0 0 0 0X0Hydropsychidae0000 K 0LimnephilidaeX0ZXXXRhyachophi1idae00X0X0Co11embo1aX0X X00CopepodaXK0 00 0HydracarinaX0X X XXOligochaetaeX XXX XXOstracodaK 000 00Source:ADF&G(1983c).Pinkandsockeyesalmonarethemostimportantincommercialcatches,bothlocallyandthroughouttherangeofthegenus.Sockeyeisthemostvalued.Chinookandcohoaremostimportantforsportfisheriesalthoughotherspeciesaretaken.ChumisgenerallyconsideredtheleastvaluedoftheNorthAmericanspecies,althoughitisabundantandcatchesarehigh.Allspeciesareusedlocallyforsubsistence.Allthespeciesspawninfreshwater,addmostbodygrowthinthemarineenvironmentsofthenorthernPacificandtheGulfofAlaska,anddieafterspawningintheirnatalstreams.Upstreammigrationsofadultscanoccurthroughouttheyear,butoccurprincipallyinJune-October(Figure1.1-2).Eggsarelaidinriverorstreamgravelsinnests(redds)wherefineparticlesarefannedawaybytheadults,mostlythefemale.Incubation,hatching,anddevelopmentthroughresorptionofthelargeyolksacoccurintheintersticesofthegravel,withfreshwaterandoxygenbeingsuppliedbyintragravelwaterflowderivedeitherfromthestreamorupwellinggroundwater.Thesalmonhavestringentrequirementsforgravelsizeandwaterpermeability,whichlimitspawninghabitatsuitability.Incubationandearlydevelopment(alevins)inreddsarestronglytemperaturedependent,withhatchingandemergencetimescharacterizedby"temperatureunits"[i.e.,thecumulativenumberofdegrees(F)timeseach24-hdayofexposure(Celsiusdegree-daysare5/9oftheFahrenheittemperatureunits).Temperatureunitsdatahavebeendevelopedlargelyinhatcheryconditions,andtheirgeneralapplicabilitytofieldsituationsandtodifferentstocksofthesamespeciesisuncertain.Salmonfryemergefromthegravelinspringwhentheyolkiscompletelyornearlyusedup.Theymaygototheoceanimmediately(chumandpink),orremaininfreshwaterforthreetofourmonths(fallchinook)orforayearormore(coho,chinook,sockeye).Freshwaterrearingisgenerallyinproductiveshallowsandembayments,particularlywhereclearwaterissuitableforsightfeeding.Youngsalmonoftenemigratetotheseaduringspringorsummerhighflows.Survivalofsmoltsintheseaisprimarilyafunctionofgrowthrateandofthetimespentinthecoastalregimewherepredatorsareplentiful.Themainmechanismwhichremovessmoltsfromcoastalareastooffshoreseemstobetransportbysurfacecurrentsenhancedby1-4Tab1e1.1-1.InvertebrateTaxaPresentinDriftNet(D)andKickScreen(K)CollectionsfromallSitesSampledin1982(XIndicatesPresenceinBothCollectingTypes,0orKIndicatesOnlyOneType,0IndicatesAbsence)FourthSiteSloughSloughSloughSloughofJulyIndian8A112021CreekRiverOipteraChironomidaeXX XX XXEmpididaeXX0XKXPsychodidaeX0X00 0SimuliidaeX0XKXXTipulidaeK0KKXXEphemeropteraBaetidae00XKX XEphemerellidaeK 0K KXXHeptageniidae00XXX XSiphlonuridae0 0K 0X0PlecopteraCapniidaeX0XKXXChloroperlidaeX0KXKXNemouridae00XKX0PerlodidaeK0XK KXTaeneopterygidaeX000X0TrichopteraBrachycentridae0000X0Glossosomatidae0 0 0 0X0Hydropsychidae0000 K 0LimnephilidaeX0ZXXXRhyachophi1idae00X0X0Co11embo1aX0X X00CopepodaXK0 00 0HydracarinaX0X X XXOligochaetaeX XXX XXOstracodaK 000 00Source:ADF&G(1983c).Pinkandsockeyesalmonarethemostimportantincommercialcatches,bothlocallyandthroughouttherangeofthegenus.Sockeyeisthemostvalued.Chinookandcohoaremostimportantforsportfisheriesalthoughotherspeciesaretaken.ChumisgenerallyconsideredtheleastvaluedoftheNorthAmericanspecies,althoughitisabundantandcatchesarehigh.Allspeciesareusedlocallyforsubsistence.Allthespeciesspawninfreshwater,addmostbodygrowthinthemarineenvironmentsofthenorthernPacificandtheGulfofAlaska,anddieafterspawningintheirnatalstreams.Upstreammigrationsofadultscanoccurthroughouttheyear,butoccurprincipallyinJune-October(Figure1.1-2).Eggsarelaidinriverorstreamgravelsinnests(redds)wherefineparticlesarefannedawaybytheadults,mostlythefemale.Incubation,hatching,anddevelopmentthroughresorptionofthelargeyolksacoccurintheintersticesofthegravel,withfreshwaterandoxygenbeingsuppliedbyintragravelwaterflowderivedeitherfromthestreamorupwellinggroundwater.Thesalmonhavestringentrequirementsforgravelsizeandwaterpermeability,whichlimitspawninghabitatsuitability.Incubationandearlydevelopment(alevins)inreddsarestronglytemperaturedependent,withhatchingandemergencetimescharacterizedby"temperatureunits"[i.e.,thecumulativenumberofdegrees(F)timeseach24-hdayofexposure(Celsiusdegree-daysare5/9oftheFahrenheittemperatureunits).Temperatureunitsdatahavebeendevelopedlargelyinhatcheryconditions,andtheirgeneralapplicabilitytofieldsituationsandtodifferentstocksofthesamespeciesisuncertain.Salmonfryemergefromthegravelinspringwhentheyolkiscompletelyornearlyusedup.Theymaygototheoceanimmediately(chumandpink),orremaininfreshwaterforthreetofourmonths(fallchinook)orforayearormore(coho,chinook,sockeye).Freshwaterrearingisgenerallyinproductiveshallowsandembayments,particularlywhereclearwaterissuitableforsightfeeding.Youngsalmonoftenemigratetotheseaduringspringorsummerhighflows.Survivalofsmoltsintheseaisprimarilyafunctionofgrowthrateandofthetimespentinthecoastalregimewherepredatorsareplentiful.Themainmechanismwhichremovessmoltsfromcoastalareastooffshoreseemstobetransportbysurfacecurrentsenhancedby 1-5SLOUGH8ASLOUGH11INDIANRIVERSOCKEYEAUGUST15.1981SOCKEYEAUGUST14.1981COHOAUGUST19.1981as%ClAOOCERA38%CHIRONOMIDAELARVAECHIRONOMIOAELARVAE"'-CHIRQNOMIOAEPUPAE&ADULTSCOHOAUGUST15.1981COHOSEPTEMBER5.1981CHINOOKAUGUST19.1981SNCHIRONOMIOAEPUPAE&AOUlT11%CHIRONOMIOAELARVAECHIRONOMIOAELARVAECHINOOKAUGUST15.1981CHINOOKAUGUST14.19814thOFJULYCREEKCOHOAUGUST18.1981,"'-CHIRONOMIOAEPUPAE&AOUlis53%CHIRONOMIOAELARVAECHIRONOMIOA£PUPAE&AOUlisSLOUGH21CHINOOKAUGUST17.1981CHINOOKAUGUST18.198145%CHIRONOMIOAEPUPAE&AOUlis4:r-.CHIRONOMIDAEPUPAE&AOUlisFigure1.1-1.AquaticInvertebratesusedforFood(StomachSamples,Aug-Sept)byJuvenileSalmonfromRepresentativeRearingHabitatsinSusitnaRiverSloughsandTributaries(ADF&G1983).PieDiagramsShowPercentageComposition.1-5SLOUGH8ASLOUGH11INDIANRIVERSOCKEYEAUGUST15.1981SOCKEYEAUGUST14.1981COHOAUGUST19.1981as%ClAOOCERA38%CHIRONOMIDAELARVAECHIRONOMIOAELARVAE"'-CHIRQNOMIOAEPUPAE&ADULTSCOHOAUGUST15.1981COHOSEPTEMBER5.1981CHINOOKAUGUST19.1981SNCHIRONOMIOAEPUPAE&AOUlT11%CHIRONOMIOAELARVAECHIRONOMIOAELARVAECHINOOKAUGUST15.1981CHINOOKAUGUST14.19814thOFJULYCREEKCOHOAUGUST18.1981,"'-CHIRONOMIOAEPUPAE&AOUlis53%CHIRONOMIOAELARVAECHIRONOMIOA£PUPAE&AOUlisSLOUGH21CHINOOKAUGUST17.1981CHINOOKAUGUST18.198145%CHIRONOMIOAEPUPAE&AOUlis4:r-.CHIRONOMIDAEPUPAE&AOUlisFigure1.1-1.AquaticInvertebratesusedforFood(StomachSamples,Aug-Sept)byJuvenileSalmonfromRepresentativeRearingHabitatsinSusitnaRiverSloughsandTributaries(ADF&G1983).PieDiagramsShowPercentageComposition. 1-6Table1.1-2.CommonandScientificNamesofFishSpeciesRecordedfromtheSusitnaBasinfreshwaterrunoff.Marinemammalsareimportantpredators,especiallyfurseal,sealion,belugaandothertoothedwhales,andthePacificwhitesidedolphin.Thelengthofoceanlifeisvaried,fromtwoyearsforpinkandcohotoseventoeightwithsomesockeye.Mostspeciesexhibitaspanofyearsforreturningadultsforacertainspawnyear,whereaspinksalmonarewhollypredictable,yieldingdistinctodd-yearandeven-yearstocks.Stocksintheoceanmixfreelyandrangewidely.ThefoodbaseoftheoceandoesnotappeartobethelimitingfactorforsizesofPacificsalmonstocks.Aprecisehomingbehaviortonatalstreamsforspawninghasfascinatedobserversandreflectsnumerousdiscretegeneticstocks,whichmustbecarefullyconsideredwhenenvironmentalchangesormitigationsarecontemplated.ChinookSalmon(Oncorhynchustshawytscha)ThisisthelargestofthePacificsalmon(thusthename"king"),whichmayreachover125lb(57kg),butitrarelyexceeds60lb(27kg)andtheaveragematurefishisnear18lb(8kg).Thereareseveralracesthroughoutitsrangethataredistinguishablebytimingofadultmigrations,whichvariesfromJanuarytolatefall,areaofspawning,andlengthoffreshwaterresidenceofjuveniles.IntheSusitna,chinookareofthespring-summerracewhichenterstheriverinlateMaytomid-July,spawnsinJulyandAugustintributaries,andgenerallygoestoseaafterspendingonefullyearinfreshwater(Figure1.1-3).Thespeciesmaturesatagesfromone(malesonly)toeightyears.Precociousmales(jacks)maybefertileevenbeforeenteringthesea.ThemedianageofadultsintheSusitnavariesaccordingtolocation,possiblyduetodiscretegeneticstocksinvarioustributaries.Forexample,in1982,chinookatSusitnaStationweremostlythree-orfour-year-olds,withsomefive-orsix-year-olds;atSunshineStationsix-year-oldspredominatedbutageswerewidelyspreadfromthreetosevenyears;atTalkeetnaStationfour-year-oldspredominated(ADF&G1983b).Basedon1982data,approximately11,000chinookentertheSusitnaaboveTalkeetna,whichisabout20%ofthosewhichpasstheSunshineStation(Figure1.1-4).AdultsmigrateThreespinesticklebackCommonNameEulachonNorthernpikeBurbotLongnosesuckerArcticlampreySlimysculpinBeringciscoHumpbackwhitefishPinksalmonChumsalmonCohosalmonSockeyesalmonChinooksalmonRoundwhitefishRainbowtroutDollyVardenLaketroutArcticgraylingCottidaeCottuscognatusGadidaeLotalotaCatostomidaeCatostomuscatostomusGasterosteidaeGasterosteusaculeatusScientificNamePetromyzontidaeLampetrajaponicaSalmonidaeCoregonuslaurettaeCoregonuspidschianOncorhynchusgorbuschaOncorhynchusketaOncorhynchuskisutchOncorhynchusnerkaOncorhynchustshawytschaProsopiumcylindraceumSalmogairdneriSalvelinusmalmaSalvelinusnamaycushThymallusarcticusOsmeridaeThaleichthyspacificusEsocidaeEsoxlucius1-6Table1.1-2.CommonandScientificNamesofFishSpeciesRecordedfromtheSusitnaBasinfreshwaterrunoff.Marinemammalsareimportantpredators,especiallyfurseal,sealion,belugaandothertoothedwhales,andthePacificwhitesidedolphin.Thelengthofoceanlifeisvaried,fromtwoyearsforpinkandcohotoseventoeightwithsomesockeye.Mostspeciesexhibitaspanofyearsforreturningadultsforacertainspawnyear,whereaspinksalmonarewhollypredictable,yieldingdistinctodd-yearandeven-yearstocks.Stocksintheoceanmixfreelyandrangewidely.ThefoodbaseoftheoceandoesnotappeartobethelimitingfactorforsizesofPacificsalmonstocks.Aprecisehomingbehaviortonatalstreamsforspawninghasfascinatedobserversandreflectsnumerousdiscretegeneticstocks,whichmustbecarefullyconsideredwhenenvironmentalchangesormitigationsarecontemplated.ChinookSalmon(Oncorhynchustshawytscha)ThisisthelargestofthePacificsalmon(thusthename"king"),whichmayreachover125lb(57kg),butitrarelyexceeds60lb(27kg)andtheaveragematurefishisnear18lb(8kg).Thereareseveralracesthroughoutitsrangethataredistinguishablebytimingofadultmigrations,whichvariesfromJanuarytolatefall,areaofspawning,andlengthoffreshwaterresidenceofjuveniles.IntheSusitna,chinookareofthespring-summerracewhichenterstheriverinlateMaytomid-July,spawnsinJulyandAugustintributaries,andgenerallygoestoseaafterspendingonefullyearinfreshwater(Figure1.1-3).Thespeciesmaturesatagesfromone(malesonly)toeightyears.Precociousmales(jacks)maybefertileevenbeforeenteringthesea.ThemedianageofadultsintheSusitnavariesaccordingtolocation,possiblyduetodiscretegeneticstocksinvarioustributaries.Forexample,in1982,chinookatSusitnaStationweremostlythree-orfour-year-olds,withsomefive-orsix-year-olds;atSunshineStationsix-year-oldspredominatedbutageswerewidelyspreadfromthreetosevenyears;atTalkeetnaStationfour-year-oldspredominated(ADF&G1983b).Basedon1982data,approximately11,000chinookentertheSusitnaaboveTalkeetna,whichisabout20%ofthosewhichpasstheSunshineStation(Figure1.1-4).AdultsmigrateThreespinesticklebackCommonNameEulachonNorthernpikeBurbotLongnosesuckerArcticlampreySlimysculpinBeringciscoHumpbackwhitefishPinksalmonChumsalmonCohosalmonSockeyesalmonChinooksalmonRoundwhitefishRainbowtroutDollyVardenLaketroutArcticgraylingCottidaeCottuscognatusGadidaeLotalotaCatostomidaeCatostomuscatostomusGasterosteidaeGasterosteusaculeatusScientificNamePetromyzontidaeLampetrajaponicaSalmonidaeCoregonuslaurettaeCoregonuspidschianOncorhynchusgorbuschaOncorhynchusketaOncorhynchuskisutchOncorhynchusnerkaOncorhynchustshawytschaProsopiumcylindraceumSalmogairdneriSalvelinusmalmaSalvelinusnamaycushThymallusarcticusOsmeridaeThaleichthyspacificusEsocidaeEsoxlucius 1-7MONTHACTIVITYJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECPINKSALMONADULTPASSAGEUPRIVER0III]SPAWNINGINCUBATlON/EMERGENCEOUTMIGRATIONCHINOOKSALMONAOULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCEJUVENILEREARINGOUTMIGRATIONCHUMSALMONADULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCEJUVENILEREARINGOUTMIGRATIONCOHOSALMONADULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCE==JUVENILEREARINGOUTMIGRATIONSOCKEYESALMONAOULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCEJUVENILEREARINGOUTMIGRATIONINTENSEACTIVITYMODERATEACTIVITYFigure1.1-2.GeneralTimjngofLife-CycleActivitiesofPacificSalmonintheSusitnaRiver.1-7MONTHACTIVITYJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECPINKSALMONADULTPASSAGEUPRIVER0III]SPAWNINGINCUBATlON/EMERGENCEOUTMIGRATIONCHINOOKSALMONAOULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCEJUVENILEREARINGOUTMIGRATIONCHUMSALMONADULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCEJUVENILEREARINGOUTMIGRATIONCOHOSALMONADULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCE==JUVENILEREARINGOUTMIGRATIONSOCKEYESALMONAOULTPASSAGEUPRIVERSPAWNINGINCUBATION/EMERGENCEJUVENILEREARINGOUTMIGRATIONINTENSEACTIVITYMODERATEACTIVITYFigure1.1-2.GeneralTimjngofLife-CycleActivitiesofPacificSalmonintheSusitnaRiver. 1-8CHINOOKSALMONII"'"S-P-AW-NI-N-G-IN-T-RI-B-UT-A-R-IE-S-(-JU-L-Y---A-U-G......,)ADULTTIMINGADULTNUMBERS1981-N.A.1982-49,600GRADUALDDWNSTREAMMDVEMENT'IAFTEREMERGENCEINMARCH-APRILJUVENILES'SECDNDSPRINGINLDWERRIVERCLEARWATERTRIBUTARIESANDSLDUGHSADULTSLATEMAY-EARLYJUNE(3-7YEARSDLD)NUMBERNDTDETERMINEDADULTNUMBERS19B1-N.A.1982-10,900JUVENILESDVERWINTERINMAINCHANNEL,SIDECHANNELSANDSLDUGHSFigure1.1-3.ChinookSalmon(Oncorhynchustshawytscha)-GeneralizedLifeCycleandHabitatSuitabilityintheSusitnaRiverDrainage.1-8CHINOOKSALMONII"'"S-P-AW-NI-N-G-IN-T-RI-B-UT-A-R-IE-S-(-JU-L-Y---A-U-G......,)ADULTTIMINGADULTNUMBERS1981-N.A.1982-49,600GRADUALDDWNSTREAMMDVEMENT'IAFTEREMERGENCEINMARCH-APRILJUVENILES'SECDNDSPRINGINLDWERRIVERCLEARWATERTRIBUTARIESANDSLDUGHSADULTSLATEMAY-EARLYJUNE(3-7YEARSDLD)NUMBERNDTDETERMINEDADULTNUMBERS19B1-N.A.1982-10,900JUVENILESDVERWINTERINMAINCHANNEL,SIDECHANNELSANDSLDUGHSFigure1.1-3.ChinookSalmon(Oncorhynchustshawytscha)-GeneralizedLifeCycleandHabitatSuitabilityintheSusitnaRiverDrainage. 1-919811982(IIPASTSUNSHINE)CHINOOK100SOCKEYE100 100COHO100100CHUM100100PINK10010019811982(IIPASTSUNSHINE)CHINOOK22.8SOCKEYE2.10.9COHO5.6 5.3CHUM5.06.8PINK2.013.3MATANUSKARIVER1981198J(IIPASTSUNSHINE)CHINOOK22.0SOCKEYE2.0COHO11.1CHUM11.4PINK16.5104.585.97.56.572.9100.919811982(IIPASTSUNSHINE)CHINOOKSOCKEYECOHOCHUMPINKFigure1.1-4.UpperCookInletandtheSusitnaDrainageShowingPercentageofSalmonMigratingPastSunshineStationandtheRelativeSizesofRunsPasttheYentnaandSunshineStations.1-919811982(IIPASTSUNSHINE)CHINOOK100SOCKEYE100 100COHO100100CHUM100100PINK10010019811982(IIPASTSUNSHINE)CHINOOK22.8SOCKEYE2.10.9COHO5.6 5.3CHUM5.06.8PINK2.013.3MATANUSKARIVER1981198J(IIPASTSUNSHINE)CHINOOK22.0SOCKEYE2.0COHO11.1CHUM11.4PINK16.5104.585.97.56.572.9100.919811982(IIPASTSUNSHINE)CHINOOKSOCKEYECOHOCHUMPINKFigure1.1-4.UpperCookInletandtheSusitnaDrainageShowingPercentageofSalmonMigratingPastSunshineStationandtheRelativeSizesofRunsPasttheYentnaandSunshineStations. 1-10Table1.1-3.DailyTemperatureUnitRequiredforEggDevelopmentofPacificSalmonTherearetwodistinctsockeyespawningrunsintotheSusitnaRiver,oneoccurringinearlyJuneandtheotherinlateJulyandearlyAugust(Figure1.1-5).ThefirstrunisprimarilyToHatchToEmergeF C F CDailyTemperatureUnitsToEyeF CChinooksalmon4502507504171,600888Co~hosalmon4502507504171,750972Chumsalmon7504171,1006111,450806Pinksalmon7504179003331,450806Sockeyesalmon9003331,2006671,8001000Source:AfterPiperetale(1982).SpeciesChinookfryschoolinthefirstyearafteremergence,butbecometerritorialastheygrow.Theyfeedonterrestrialandaquaticinsectsandsmallcrustaceans(ADF&G1983c,Becker1973,Daubleetale1980).AnalysisofscalesfromadultchinookintheSusitnain1981and1982showedthatmostjuvenilesleavefreshwaterintheirsecondyear.Thereisagradualdownstreammovementafteremergence,withmajornurseryareasoccurringinclear-watertributarymouthsandsloughsinsummer.Mainstemandsloughsitesreceiveprogressivelygreateruseinwinterastributaryflowsdiminishandicedevelops(ADF&G1981d).Chinookjuvenileschangefromterritorialfeedinginstreamstohidingwithoutfeedingincoveratlowtemperaturesnear41°F(5°C)(ChapmanandBjornn1969).Juvenilegrowthistemperaturedependentwithoptimumnear15°C.SockeyeSalmon(Oncorhynchusnerka)ThisspeciesisthemostvaluableofthePacificsalm~n,foritishighlyprizedforitshighoilcontent,excellentflavor,colorofflesh,anduniformsize.ItisfoundfromJapantoCalifornia,butentersriverssouthoftheColumbiaRiveronlyasstrays.Itentersrivers,usuallythosefedbylakes,inMarchtoJuly.Spawningismostcommoninlakesorimmediatelyadjacentininletoroutletstreams,althoughsomesockeyespawninriverswithoutlakes.Youngrear,usuallyinlakes,foronetothreeyearsandmigratetotheseaas0.14to0.21oz(4-6g)smoltsinMarchtoMay.Someracesarenonmigratoryandareknownaskokanee,whicharepopularamongsportsmeninthenorthwestUnitedStates.Somesockeyeofsea-runstockwillalsolivetheirwholelivesinfreshwater.Kokaneehavebeenpopularinreservoirsbehindhighdamswheretheyprovideahigh-quality,naturallysustained,salmonidfisherythatreplacessea-runstockswhicharecutoff.Incubationofeggsinthereddsoccursthroughthewinter,withhatchoccurringinearlyspring.Alevinsgenerallyremainintheredduntiltheyolksachasbeenabsorbedandthenemergefromthegravelandbecomefree-swimming,feedingfry(Morrow1980).Standardreferencesfordailytemperatureunits(TU)requiredforhatchingandemergencesuggest750and1600,respectively(Piperetale1982;Table1.1-3).Detailedstudiesshowedconsiderablevariability,inTUsforchinooksalmon,however,evenamongeggsfromthesamefemale,with900to1000TUstohatchandnear1900TUsforemergenceforexperimentalchinookreddsontheSkagitRiver,Washington(Graybilletale1979).Olsonetale(1970)foundthetemperature-unitapproachsatisfactoryforestimatingdevelopmentalstagesofColumbiaRiverfallchinookspawnedoverawiderangeofdates.Theyestimatedabout900to1000TUsforhatchingand1600forbeginningoffeeding(emergence).Warmertemperaturesduringincubationappeartoyieldsmallerfryattimeofemergence,althoughthedifferenceisnotgreat(Olsonetale1970;Seymour1956).WhenGraybilletale(1979)examinedrivertemperaturesthatwereshiftedtoeitherwarmerorcoolerregimesthannormallyexperienced,aformofTUcompensationwasobservedthatsomewhatdamperedthepredictedchangesintimingofemergence.DatafortemperaturedependenceofincubationofSusitnaRiverstocksarenotavailable.closetoshorelinesindepthsoflessthan4ft(1.2m).Traveltonatalstreamsisinterspersedwithmillingneartributarymouths(ADF&G1981b,1983b).EachfemaleinAlaskawilldeposit4,000to13,000eggsintributarystreamgravels(Morrow1980).HabitatfeaturespreferredforspawninghavenotbeenidentifiedfortheSusitnastocks,butintheSkagitRiver,Washington,the80%intervals(rangeencompassing80%ofthedata,centeredonthemedian)were1.7to4.2ft(0.5-1.2m)fordepthand1.8-3.7ft/s(0.5-1.1m/s)forvelocity(Graybilletal1979).1-10Table1.1-3.DailyTemperatureUnitRequiredforEggDevelopmentofPacificSalmonTherearetwodistinctsockeyespawningrunsintotheSusitnaRiver,oneoccurringinearlyJuneandtheotherinlateJulyandearlyAugust(Figure1.1-5).ThefirstrunisprimarilyToHatchToEmergeF C F CDailyTemperatureUnitsToEyeF CChinooksalmon4502507504171,600888Co~hosalmon4502507504171,750972Chumsalmon7504171,1006111,450806Pinksalmon7504179003331,450806Sockeyesalmon9003331,2006671,8001000Source:AfterPiperetale(1982).SpeciesChinookfryschoolinthefirstyearafteremergence,butbecometerritorialastheygrow.Theyfeedonterrestrialandaquaticinsectsandsmallcrustaceans(ADF&G1983c,Becker1973,Daubleetale1980).AnalysisofscalesfromadultchinookintheSusitnain1981and1982showedthatmostjuvenilesleavefreshwaterintheirsecondyear.Thereisagradualdownstreammovementafteremergence,withmajornurseryareasoccurringinclear-watertributarymouthsandsloughsinsummer.Mainstemandsloughsitesreceiveprogressivelygreateruseinwinterastributaryflowsdiminishandicedevelops(ADF&G1981d).Chinookjuvenileschangefromterritorialfeedinginstreamstohidingwithoutfeedingincoveratlowtemperaturesnear41°F(5°C)(ChapmanandBjornn1969).Juvenilegrowthistemperaturedependentwithoptimumnear15°C.SockeyeSalmon(Oncorhynchusnerka)ThisspeciesisthemostvaluableofthePacificsalm~n,foritishighlyprizedforitshighoilcontent,excellentflavor,colorofflesh,anduniformsize.ItisfoundfromJapantoCalifornia,butentersriverssouthoftheColumbiaRiveronlyasstrays.Itentersrivers,usuallythosefedbylakes,inMarchtoJuly.Spawningismostcommoninlakesorimmediatelyadjacentininletoroutletstreams,althoughsomesockeyespawninriverswithoutlakes.Youngrear,usuallyinlakes,foronetothreeyearsandmigratetotheseaas0.14to0.21oz(4-6g)smoltsinMarchtoMay.Someracesarenonmigratoryandareknownaskokanee,whicharepopularamongsportsmeninthenorthwestUnitedStates.Somesockeyeofsea-runstockwillalsolivetheirwholelivesinfreshwater.Kokaneehavebeenpopularinreservoirsbehindhighdamswheretheyprovideahigh-quality,naturallysustained,salmonidfisherythatreplacessea-runstockswhicharecutoff.Incubationofeggsinthereddsoccursthroughthewinter,withhatchoccurringinearlyspring.Alevinsgenerallyremainintheredduntiltheyolksachasbeenabsorbedandthenemergefromthegravelandbecomefree-swimming,feedingfry(Morrow1980).Standardreferencesfordailytemperatureunits(TU)requiredforhatchingandemergencesuggest750and1600,respectively(Piperetale1982;Table1.1-3).Detailedstudiesshowedconsiderablevariability,inTUsforchinooksalmon,however,evenamongeggsfromthesamefemale,with900to1000TUstohatchandnear1900TUsforemergenceforexperimentalchinookreddsontheSkagitRiver,Washington(Graybilletale1979).Olsonetale(1970)foundthetemperature-unitapproachsatisfactoryforestimatingdevelopmentalstagesofColumbiaRiverfallchinookspawnedoverawiderangeofdates.Theyestimatedabout900to1000TUsforhatchingand1600forbeginningoffeeding(emergence).Warmertemperaturesduringincubationappeartoyieldsmallerfryattimeofemergence,althoughthedifferenceisnotgreat(Olsonetale1970;Seymour1956).WhenGraybilletale(1979)examinedrivertemperaturesthatwereshiftedtoeitherwarmerorcoolerregimesthannormallyexperienced,aformofTUcompensationwasobservedthatsomewhatdamperedthepredictedchangesintimingofemergence.DatafortemperaturedependenceofincubationofSusitnaRiverstocksarenotavailable.closetoshorelinesindepthsoflessthan4ft(1.2m).Traveltonatalstreamsisinterspersedwithmillingneartributarymouths(ADF&G1981b,1983b).EachfemaleinAlaskawilldeposit4,000to13,000eggsintributarystreamgravels(Morrow1980).HabitatfeaturespreferredforspawninghavenotbeenidentifiedfortheSusitnastocks,butintheSkagitRiver,Washington,the80%intervals(rangeencompassing80%ofthedata,centeredonthemedian)were1.7to4.2ft(0.5-1.2m)fordepthand1.8-3.7ft/s(0.5-1.1m/s)forvelocity(Graybilletal1979). 1-11destinedfortheFishCreeksubdrainageofChunila(Clear)Creek,aTalkeetnaRivertributarythathastwolakes,PapaBearandSockeye.TheyspawnthereattheendofJulyandbeginningofAugust.ThesecondrunisdistributedthroughtheSusitnariversystem.Inbothruns,adultsareprimarilyfiveyearsoldandmigratedtosaltwaterintheirsecondyear.Thesecond-runfish,however,hasawiderrangeofages(3-7),withnearlyaquarteroftherunbeingfour-year-olds.Second-runsockeyespawninsloughsofthemainriverandsometributarymouths,occupyingaboutone-thirdofthesloughsalongtheTalkeetna-DevilCanyonreach.ThesefisharenotdistinctstocksfromthoseofthesecondrunwhichentertheTalkeetnaandChulitnarivers,basedonstudiesbyBernardetale(1983).ThereisevidencethatsockeyespawnedinlakesassociatedwithChaseCreek(RM106.9)(Barretc1974)andIndianRiver(RM138.6),althoughnonewasobservedintheSuHydrostudies.PeakspawningactivityoccursduringthelastweekinAugustandthefirstthreeweeksofSeptember.HabitatfeaturespreferredbythespeciesforspawningweresummarizedinsuitabilitycurvesbyBovee(1978)(Figure1.1-5).Kokaneerequirementsdiffersomewhatfromthoseofanadromousstocks,particularlyinrequiringslowerwatervelocities.Adultsockeyearebelievedtospendabout12datthespawningsitebeforedying,basedonestimatesderivedfortheChakachamnasystemonthewestsideofCookInlet(BechtelCivilandMinerals,Inc.1983).Thisinformationisusedtoconvertaerialfishcountstoestimatesofspawning.Maturesockeyefemalestypicallydeposit2500to4300eggsinagraveluntilemergingfromApriltoJune.Approximately1200TUs(F)aregenerallyrequiredforhatchingand1800foremergence(Piperetal1982;Table1.1-3).Therelationshipbetweendevelopmentrateandtemperatureforthespecies,includingSusitnastocks,wassummarizedbyWangaardandBurger(1983)as:ln(3.71)+0.15(temperature)ln(2.61)+0.14(temperature)whereRh=developmentrateperday(x1000)tohatchingRa=developmentrateperday(x1000)tocompleteyolkabsorption.ThemajoremergenceofsockeyefryoccursinMarchintheSusitna,withcompleteyolksacabsorptioninApril,atlengthsofapproximately33mm.Elsewhere,wheresockeyespawninornearlakes,frymovetothelakeforonetothreeyearsofrearingbeforemigratingtotheocean.TheSusitnaaboveTalkeetnahasfewlakes,however,andthefateoffryproducedinthatreachisuncertain.ThereappearstobeageneraldownstreamredistributionoffryduringJune-Julyoftheirfirstsummer,basedonscoop-trapsamples.Scalesofreturningadultsshowfewfishenteringtheoceanintheirfirstyear(althoughsamplesfromCurryStationarehighestat1%),suggestingeitherpoorsurvivalofslough-spawnedfryoroverwinteringandrearinginthelowerriver.Collectionoflargenumbersof0+juvenilesandseveral1+fishinsloughsnotusedforspawningsuggeststhatsloughsmaysubstitutefornormallakerearing.GrowthshownbyjuvenilescollectedthroughoutthesummerintrapssuggeststhatimportantrearinghabitatmaybefoundintheriveraboveTalkeetna.SockeyefryintheSusitnafeedonallstagesofaquaticandterrestrialinsects(especiallychironomids)andcladoceranandcopepodzooplankton.Zooplanktonisthenormalfoodoflake-rearedfry.Growth,energetics,andperformanceofjuvenilesockeyesalmonhavebeenstudiedextensively,particularlyofBritishColumbiastocksinrelationtowatertemperature(Brett1971,1974).Thereisanotablethermalzoneofoptimiummetabolismandperformancenear59°F(15°C),whichishigherthantemperaturesnormallyfoundintheSusitnaRiver,butwhichmayoCCurinlakes.Boththeupperandlowerlethaltemperaturesshowacontinuousincreaseovermostoftheacclimation(priorholding)temperaturerange.Anupperplateauoccursnear77°F(25°C)forthehighlethals,andthereisacorrespondinglowerplateauforthelowlethals,justbelow32°F(O°C).Juvenilesockeyeprefer59°F(15°C)inthermalgradients,withselectedtemperaturefallingprogressivelyoneithersideasacclimationtemperaturesdepartfurtherfromthepreferred.Standardorrestingmetabolismdisplaysthealmostuniversalcharacteristicofcontinuousincreasewithtemperature,whereastheactiveratereachesanoptimumat59°F(15°C)anddecreasesthereafterinaslowdeclinetothelethaltemperature.Thesemetabolicrelationshipsarereflectedinthecurvesformetabolicscopeofactivityandperformancewhichbothshowprominentoptimaat59°F(15°C).Youngsockeyeshowasharpgrowthoptimumat59°F(15°C);thegrowthcurveflattenswithincreasingsizeandage.Aprogressiveshifttoalowertemperatureoccursinthegrowthoptimumasthequantityoffoodisrestricted.Maximumfoodintakeoccursnear63°F(17°C)andappetiteisinhibitedat75°F(24°C).Grossfoodconversionefficiency(%fleshfromfood)wascalculatedfromrationandgrowthrateandshowsabroadzoneofhighlevelsfromabout41°F(5°C)to63°F(17°C)withanoptimumnear53°F(11.5°C)andarapiddeclineabove68°F(20°C).Infood-limitedconditions,juvenilesockeyesalmoninlakesshowedanextensivediurnalmigrationinsummerbetweenthesurfaceatabout63°F(17°C)andthebottomatabout41°F(5°C),whichispresumedtobeanenergy-conserving,growth-maximizingecologicalstrategy.1-11destinedfortheFishCreeksubdrainageofChunila(Clear)Creek,aTalkeetnaRivertributarythathastwolakes,PapaBearandSockeye.TheyspawnthereattheendofJulyandbeginningofAugust.ThesecondrunisdistributedthroughtheSusitnariversystem.Inbothruns,adultsareprimarilyfiveyearsoldandmigratedtosaltwaterintheirsecondyear.Thesecond-runfish,however,hasawiderrangeofages(3-7),withnearlyaquarteroftherunbeingfour-year-olds.Second-runsockeyespawninsloughsofthemainriverandsometributarymouths,occupyingaboutone-thirdofthesloughsalongtheTalkeetna-DevilCanyonreach.ThesefisharenotdistinctstocksfromthoseofthesecondrunwhichentertheTalkeetnaandChulitnarivers,basedonstudiesbyBernardetale(1983).ThereisevidencethatsockeyespawnedinlakesassociatedwithChaseCreek(RM106.9)(Barretc1974)andIndianRiver(RM138.6),althoughnonewasobservedintheSuHydrostudies.PeakspawningactivityoccursduringthelastweekinAugustandthefirstthreeweeksofSeptember.HabitatfeaturespreferredbythespeciesforspawningweresummarizedinsuitabilitycurvesbyBovee(1978)(Figure1.1-5).Kokaneerequirementsdiffersomewhatfromthoseofanadromousstocks,particularlyinrequiringslowerwatervelocities.Adultsockeyearebelievedtospendabout12datthespawningsitebeforedying,basedonestimatesderivedfortheChakachamnasystemonthewestsideofCookInlet(BechtelCivilandMinerals,Inc.1983).Thisinformationisusedtoconvertaerialfishcountstoestimatesofspawning.Maturesockeyefemalestypicallydeposit2500to4300eggsinagraveluntilemergingfromApriltoJune.Approximately1200TUs(F)aregenerallyrequiredforhatchingand1800foremergence(Piperetal1982;Table1.1-3).Therelationshipbetweendevelopmentrateandtemperatureforthespecies,includingSusitnastocks,wassummarizedbyWangaardandBurger(1983)as:ln(3.71)+0.15(temperature)ln(2.61)+0.14(temperature)whereRh=developmentrateperday(x1000)tohatchingRa=developmentrateperday(x1000)tocompleteyolkabsorption.ThemajoremergenceofsockeyefryoccursinMarchintheSusitna,withcompleteyolksacabsorptioninApril,atlengthsofapproximately33mm.Elsewhere,wheresockeyespawninornearlakes,frymovetothelakeforonetothreeyearsofrearingbeforemigratingtotheocean.TheSusitnaaboveTalkeetnahasfewlakes,however,andthefateoffryproducedinthatreachisuncertain.ThereappearstobeageneraldownstreamredistributionoffryduringJune-Julyoftheirfirstsummer,basedonscoop-trapsamples.Scalesofreturningadultsshowfewfishenteringtheoceanintheirfirstyear(althoughsamplesfromCurryStationarehighestat1%),suggestingeitherpoorsurvivalofslough-spawnedfryoroverwinteringandrearinginthelowerriver.Collectionoflargenumbersof0+juvenilesandseveral1+fishinsloughsnotusedforspawningsuggeststhatsloughsmaysubstitutefornormallakerearing.GrowthshownbyjuvenilescollectedthroughoutthesummerintrapssuggeststhatimportantrearinghabitatmaybefoundintheriveraboveTalkeetna.SockeyefryintheSusitnafeedonallstagesofaquaticandterrestrialinsects(especiallychironomids)andcladoceranandcopepodzooplankton.Zooplanktonisthenormalfoodoflake-rearedfry.Growth,energetics,andperformanceofjuvenilesockeyesalmonhavebeenstudiedextensively,particularlyofBritishColumbiastocksinrelationtowatertemperature(Brett1971,1974).Thereisanotablethermalzoneofoptimiummetabolismandperformancenear59°F(15°C),whichishigherthantemperaturesnormallyfoundintheSusitnaRiver,butwhichmayoCCurinlakes.Boththeupperandlowerlethaltemperaturesshowacontinuousincreaseovermostoftheacclimation(priorholding)temperaturerange.Anupperplateauoccursnear77°F(25°C)forthehighlethals,andthereisacorrespondinglowerplateauforthelowlethals,justbelow32°F(O°C).Juvenilesockeyeprefer59°F(15°C)inthermalgradients,withselectedtemperaturefallingprogressivelyoneithersideasacclimationtemperaturesdepartfurtherfromthepreferred.Standardorrestingmetabolismdisplaysthealmostuniversalcharacteristicofcontinuousincreasewithtemperature,whereastheactiveratereachesanoptimumat59°F(15°C)anddecreasesthereafterinaslowdeclinetothelethaltemperature.Thesemetabolicrelationshipsarereflectedinthecurvesformetabolicscopeofactivityandperformancewhichbothshowprominentoptimaat59°F(15°C).Youngsockeyeshowasharpgrowthoptimumat59°F(15°C);thegrowthcurveflattenswithincreasingsizeandage.Aprogressiveshifttoalowertemperatureoccursinthegrowthoptimumasthequantityoffoodisrestricted.Maximumfoodintakeoccursnear63°F(17°C)andappetiteisinhibitedat75°F(24°C).Grossfoodconversionefficiency(%fleshfromfood)wascalculatedfromrationandgrowthrateandshowsabroadzoneofhighlevelsfromabout41°F(5°C)to63°F(17°C)withanoptimumnear53°F(11.5°C)andarapiddeclineabove68°F(20°C).Infood-limitedconditions,juvenilesockeyesalmoninlakesshowedanextensivediurnalmigrationinsummerbetweenthesurfaceatabout63°F(17°C)andthebottomatabout41°F(5°C),whichispresumedtobeanenergy-conserving,growth-maximizingecologicalstrategy. 1-12SOCKEYESALMONADULTNUMBERS(SECONDRUN)1981-133,0001982-151,000ADULTTIMING1982REARING1YEARINLAKES(FIRSTRUN)SECONDRUNSPAWNINGINSLOUGHSANDSOMETRIBUTARYMOUTHS(AUG.-SEPT.)DEVILCANYONSUS//;/114JUVENILE(SECONDRUN)OVERWINTERINGINLOWERRIVER(1)TOTALS:1981-272,0001982-265,000ADULTNUMBERS(SECONDRUN)1981-4,8001982-3,100ADULTSFIRSTRUN-EARLYJUNE(5YEAROLDS)SECONDRUN-LATEJULY(3-7YEARSOLD)Figure1.1-5.SockeyeSalmon(Oncorhynchusnerka)-GeneralizedLifeCycleintheSusitnaRiverDrainage.1-12SOCKEYESALMONADULTNUMBERS(SECONDRUN)1981-133,0001982-151,000ADULTTIMING1982REARING1YEARINLAKES(FIRSTRUN)SECONDRUNSPAWNINGINSLOUGHSANDSOMETRIBUTARYMOUTHS(AUG.-SEPT.)DEVILCANYONSUS//;/114JUVENILE(SECONDRUN)OVERWINTERINGINLOWERRIVER(1)TOTALS:1981-272,0001982-265,000ADULTNUMBERS(SECONDRUN)1981-4,8001982-3,100ADULTSFIRSTRUN-EARLYJUNE(5YEAROLDS)SECONDRUN-LATEJULY(3-7YEARSOLD)Figure1.1-5.SockeyeSalmon(Oncorhynchusnerka)-GeneralizedLifeCycleintheSusitnaRiverDrainage. 1-13Out-migrationofsockeyesmoltsmaybetriggeredbytemperature.Suddenincreasesintemperaturereversedrheotoxisfrompositive(upstream)tonegative(downstream)inlaboratorystudies(KeenleysideandHoar1955).Positiverheotoxispredominatedinfishacclimatedtobelow50°F(10°C),whereasdownstreamswimmingpredominatedabovethatlevel.Outmigrationoftenpeaksattemperaturesnear50°F(10°C),althoughitcanbeginfromlakeswhensurfacetemperaturesexceed39to41°F(4-5°C).Outmigrationdatesforjuvenilesockeyesalmonfromlakescoincidewiththegeneralclimaticconditionsoverthenorth-southrangeofthespecies,withmoresouthern(warmer)populations migratingearlierthanmorenorthernpopulations(Hartmanetal.1967).Short-termelevationsoftemperaturestimulatedpulsesofoutmigration,whereascooltemperaturesdecreasedmigrationrates.CohoSalmon(Oncorhynchuskisutch)Cohosalmon,alsocalledsilversalmonorhooknose,isapopulargamefishthatmayreachover30lb(13.6kg),although6to12lb(2.7-5.4kg)atmaturityistypical.ThespeciesisfoundfromCaliforniatoJapan,andithasbeenintroducedsuccessfullyinfreshwater,especiallytheLaurentianGreatLakes.IncoastalwatersoftheNorthwestandAlaska,cohosalmondonottravelfarfromtheparentstream.PopulationsoriginatinginAlaskacontributeprincipallytotheAlaskanfishery.Cohospawnatagesoftwotofouryearsinriversandstreamswhichtheyenterinsummer,withspawningcompleteinthefall.Younggenerallyremaininfreshwaterforayear,buttimingisnottightlyregulatedandsomegoearlierwhileotherswaituntiltheirthirdyear.IntheSusitna,runsapproaching80,000adults(1981and1982estimateswere36,000and79,800,respectively)entertheriverbeginninginlateJuneorearlyJuly,peakingbetweenmid-JulyandearlyAugust,andendinginSeptember(Figure1.1-2,1.1-6).Aboutone-halfofthesediverttotheYentna(Figure1.1-4).Almostallfishareeitherthree-year-oldsthatemigratetheirsecondyearorfour-year-oldsthatleavefreshwaterintheirthirdyear(asmallpercentagearefour-orfive-year-oldsthatgotoseaintheirfourthyear).Theyounger-maturingfishseemdestinedfortheriverreachesaboveTalkeetna.Migrationischaracterizedbyperiodsofmillingorholdinginsemiplacidareassuchasnearmouthsofclear-watertributaries.Susitnacohospawnineitherthemainstem,wheretheyminglewithchumsalmon,orintributarycreeks;sloughsareutilizedrarely.PeakSusitnaspawningoccursgenerallyinmid-September,withconsiderablevariationamongsites.HabitatfeaturespreferredforspawningintheSusitnaarenotwellestablished,butgeneralizedsuitabilitycurvesforvelocity,depth,temperature,andsubstrateweredevelopedbyBovee(1978).Theaverageof3500eggsdepositedbyafemale(Hartman1971)incubateinthegravelthroughthewinteruntilemergenceinMarchorApril.Approximately1750TUs(F)arerequiredforemergence,basedonhatcheryexperiences(Piperetal.1982).Althoughexacttemperaturedependenceofdevelopmentrateprobablyvariesamongstocks,therearenodataspecifictotheSusitnastocks.FryarefirstcapturedintheSusitnainJune.Cohojuvenilesspendtwoyearsinfreshwaterbeforeemigratingtotheocean.Thus,inanysummerseason,theremaybethreeyearclassespresent:newlyemergedfry(0+),yearlings(1+),andtwo-year-oldfishpriortoemigration(2+).TheyutilizethemainstemandsloughsforrearingandarecapturedindownstreammigranttrapsthroughouttheJune-Octoberperiod.Astemperaturesdropinwinter,cohojuvenilestypicallychangefrombeingsolitaryandterritorialfeederstohidingwithoutfeedingincoverorindeepwater,ofteningroups(Hartman1965;BustardandNarver1975a).NaturalorartificialsidepoolsusedbycohofryinPacificcoaststreamsaswinterrefugewereattractivetothemnear35to41°F(2to5°C),butthefishleftforthemainstemathighertemperatures(BustardandNarver1975b).IntheSusitna,theyusesloughsforoverwintering.Althoughcohosmoltoutmigrationseemstobetimedbylunarcontrolofthyroxinelevels,rapidtemperatureincreaseshavebeenshowntocauseachangeinrheotoxis(currentorientation)frompositive(upstream)tonegative(downstream)(KeenleysideandHoar1955).Temperaturesintherange43to48°F(6-9°C)areassociatedwithpredominantlypositiverheotoxis,whereas57to70°F(14-210C)temperaturesareassociatedwithdownstreamswimming.Thechangeoveroccursnearthetemperatureofmaximaldownstreammigrationinthestockstudied,about50°F(10°C).EnvironmentalrequirementsofcohosalmonjuvenilesarewellknownfromhatcheryexperienceinthePacificNorthwest.RelevanceofthisinformationforSusitnastockisunknown.ChumSalmon(Oncorhynchusketa)ThisPacificsalmonspecies,alsocalledthedogsalmoninAlaska,isthirdinvalueforcommercialsalmonfisheries(behindsockeyeandpink),butitisinfrequentlysoughtbysportfishermen.Itcanreachaweightof33lb(15kg),althoughitisususallytakeninsizesof8-18lb(3.6-8kg).Itsrange,thewidestofanyPacificsalmon,isfromnorthernCaliforniatoKoreaandJapan,whereitusuallyspawnsinthelowerreachesofcoastalrivers.InAlaska,however,itrangesfarupthemajorrivers,includingtheSusitna;intheYukonthe1-13Out-migrationofsockeyesmoltsmaybetriggeredbytemperature.Suddenincreasesintemperaturereversedrheotoxisfrompositive(upstream)tonegative(downstream)inlaboratorystudies(KeenleysideandHoar1955).Positiverheotoxispredominatedinfishacclimatedtobelow50°F(10°C),whereasdownstreamswimmingpredominatedabovethatlevel.Outmigrationoftenpeaksattemperaturesnear50°F(10°C),althoughitcanbeginfromlakeswhensurfacetemperaturesexceed39to41°F(4-5°C).Outmigrationdatesforjuvenilesockeyesalmonfromlakescoincidewiththegeneralclimaticconditionsoverthenorth-southrangeofthespecies,withmoresouthern(warmer)populations migratingearlierthanmorenorthernpopulations(Hartmanetal.1967).Short-termelevationsoftemperaturestimulatedpulsesofoutmigration,whereascooltemperaturesdecreasedmigrationrates.CohoSalmon(Oncorhynchuskisutch)Cohosalmon,alsocalledsilversalmonorhooknose,isapopulargamefishthatmayreachover30lb(13.6kg),although6to12lb(2.7-5.4kg)atmaturityistypical.ThespeciesisfoundfromCaliforniatoJapan,andithasbeenintroducedsuccessfullyinfreshwater,especiallytheLaurentianGreatLakes.IncoastalwatersoftheNorthwestandAlaska,cohosalmondonottravelfarfromtheparentstream.PopulationsoriginatinginAlaskacontributeprincipallytotheAlaskanfishery.Cohospawnatagesoftwotofouryearsinriversandstreamswhichtheyenterinsummer,withspawningcompleteinthefall.Younggenerallyremaininfreshwaterforayear,buttimingisnottightlyregulatedandsomegoearlierwhileotherswaituntiltheirthirdyear.IntheSusitna,runsapproaching80,000adults(1981and1982estimateswere36,000and79,800,respectively)entertheriverbeginninginlateJuneorearlyJuly,peakingbetweenmid-JulyandearlyAugust,andendinginSeptember(Figure1.1-2,1.1-6).Aboutone-halfofthesediverttotheYentna(Figure1.1-4).Almostallfishareeitherthree-year-oldsthatemigratetheirsecondyearorfour-year-oldsthatleavefreshwaterintheirthirdyear(asmallpercentagearefour-orfive-year-oldsthatgotoseaintheirfourthyear).Theyounger-maturingfishseemdestinedfortheriverreachesaboveTalkeetna.Migrationischaracterizedbyperiodsofmillingorholdinginsemiplacidareassuchasnearmouthsofclear-watertributaries.Susitnacohospawnineitherthemainstem,wheretheyminglewithchumsalmon,orintributarycreeks;sloughsareutilizedrarely.PeakSusitnaspawningoccursgenerallyinmid-September,withconsiderablevariationamongsites.HabitatfeaturespreferredforspawningintheSusitnaarenotwellestablished,butgeneralizedsuitabilitycurvesforvelocity,depth,temperature,andsubstrateweredevelopedbyBovee(1978).Theaverageof3500eggsdepositedbyafemale(Hartman1971)incubateinthegravelthroughthewinteruntilemergenceinMarchorApril.Approximately1750TUs(F)arerequiredforemergence,basedonhatcheryexperiences(Piperetal.1982).Althoughexacttemperaturedependenceofdevelopmentrateprobablyvariesamongstocks,therearenodataspecifictotheSusitnastocks.FryarefirstcapturedintheSusitnainJune.Cohojuvenilesspendtwoyearsinfreshwaterbeforeemigratingtotheocean.Thus,inanysummerseason,theremaybethreeyearclassespresent:newlyemergedfry(0+),yearlings(1+),andtwo-year-oldfishpriortoemigration(2+).TheyutilizethemainstemandsloughsforrearingandarecapturedindownstreammigranttrapsthroughouttheJune-Octoberperiod.Astemperaturesdropinwinter,cohojuvenilestypicallychangefrombeingsolitaryandterritorialfeederstohidingwithoutfeedingincoverorindeepwater,ofteningroups(Hartman1965;BustardandNarver1975a).NaturalorartificialsidepoolsusedbycohofryinPacificcoaststreamsaswinterrefugewereattractivetothemnear35to41°F(2to5°C),butthefishleftforthemainstemathighertemperatures(BustardandNarver1975b).IntheSusitna,theyusesloughsforoverwintering.Althoughcohosmoltoutmigrationseemstobetimedbylunarcontrolofthyroxinelevels,rapidtemperatureincreaseshavebeenshowntocauseachangeinrheotoxis(currentorientation)frompositive(upstream)tonegative(downstream)(KeenleysideandHoar1955).Temperaturesintherange43to48°F(6-9°C)areassociatedwithpredominantlypositiverheotoxis,whereas57to70°F(14-210C)temperaturesareassociatedwithdownstreamswimming.Thechangeoveroccursnearthetemperatureofmaximaldownstreammigrationinthestockstudied,about50°F(10°C).EnvironmentalrequirementsofcohosalmonjuvenilesarewellknownfromhatcheryexperienceinthePacificNorthwest.RelevanceofthisinformationforSusitnastockisunknown.ChumSalmon(Oncorhynchusketa)ThisPacificsalmonspecies,alsocalledthedogsalmoninAlaska,isthirdinvalueforcommercialsalmonfisheries(behindsockeyeandpink),butitisinfrequentlysoughtbysportfishermen.Itcanreachaweightof33lb(15kg),althoughitisususallytakeninsizesof8-18lb(3.6-8kg).Itsrange,thewidestofanyPacificsalmon,isfromnorthernCaliforniatoKoreaandJapan,whereitusuallyspawnsinthelowerreachesofcoastalrivers.InAlaska,however,itrangesfarupthemajorrivers,includingtheSusitna;intheYukonthe Figure1.1-6.Cohosalmon(Oncorhynchuskisutch)-GeneralizedLifeCycleintheSusitnaRiverDrainage.AUGSEPTADULTNUMBERS1981-19,8001982-45,700EMIGRATIONPEAKSINJUNE;CONTINUESTHROUGHOCT.ADULTS·LATEJUNE-SEPT.(3-4YEARSOLD)1981-36,0001982-79,800JUVENILEOVERWINTERINGINSLOUGHSADULTNUMBERS1981-3,3001982-5,1001-14ADULTNUMBERS19B1-1,1001982-2,400COHOSALMON\.-----:..--..,SPAWNINGINTRIBUTARIES'"ANDDCCASIDNALLYIN'-....SLOUGHSANDMAINSTEM(LATESEPT.-EARLYOCT.)f:~:.rIp<'<-1-r,r-1-:'),....----:...-;\\_/}----,'<1/;'11/."'1:>\JUVENILESREARFOR~'7TWOYEARSINFRESHWATERFigure1.1-6.Cohosalmon(Oncorhynchuskisutch)-GeneralizedLifeCycleintheSusitnaRiverDrainage.AUGSEPTADULTNUMBERS1981-19,8001982-45,700EMIGRATIONPEAKSINJUNE;CONTINUESTHROUGHOCT.ADULTS·LATEJUNE-SEPT.(3-4YEARSOLD)1981-36,0001982-79,800JUVENILEOVERWINTERINGINSLOUGHSADULTNUMBERS1981-3,3001982-5,1001-14ADULTNUMBERS19B1-1,1001982-2,400COHOSALMON\.-----:..--..,SPAWNINGINTRIBUTARIES'"ANDDCCASIDNALLYIN'-....SLOUGHSANDMAINSTEM(LATESEPT.-EARLYOCT.)f:~:.rIp<'<-1-r,r-1-:'),....----:...-;\\_/}----,'<1/;'11/."'1:>\JUVENILESREARFOR~'7TWOYEARSINFRESHWATER 1-15speciesisfound2000mi(3200km)fromthesea.Runsofchumaremarkedbywideyearlyfluctuationsinnumbers,andinpartofitsrangeithasdistinctsummerandfallforms.Itgenerallymaturesat4to5yearsofage,whenitentersriversinJulytoDecember.Youngmigrateoutofspawningriverssoonafteremergingfromredds(within1monthincoastalsitesbutupto3monthslaterinAlaskarivers)andmostofthelifeisspentinthesea(Bakka1a1970,Hale1981c).SusitnaRiverchumenterfreshwaterbetweenearlyJulyandmid-Septemberinrunsthatmaynumberabout400,000fish(1981and1982estimateswere283,000and458,000,respectively)(Figure1.1-7).PeakmigrationpastSunshineStationisinearlyAugust.TheYentnaaccountedforabout28,000fishofthetotalin1982(Figure1.1-4).Migrantsareprimarilyfour-year-01dfish,althoughthree-andfive-year-01dsrepresentabout15%.Considerablemillingintheriver,tributarymouths,andthemouthofDevilCanyonseemscharacteristicbeforefishseekspawningsites,mostlyinsloughs.Afewmainchannelandsidechannelspawningsites(10in1982)wereidentified,allabovetheChulitnaconfluence.Chumspawninthesamegeneralsloughareasandatthesametime(mid-Augusttomid-September)assockeye.Tributariesarealsoutilized,mainlyIndianRiver,FourthofJulyCreek,andPortageCreek,indecreasingorderofimportance.Temperaturessuitableformigrationrangefromabout8to14°C,withchangesinthisrangehavinglittleinfluenceonupstreammigration(Hale1981b).ChumsalmonhavelessabilitytosurmountrapidsandwaterfallsthanotherspeciesofPacificsalmon(ScottandCrossman1973).Waterflowsofabout2.5mlsareneartheupperlimitofsustainedswimmingspeed(Thompson1972).Adultchumswereobservedtravelingupstreaminshallowriffleswiththeupperpartoftheirbodiesabovewater,butthedistancethatcouldbecoveredinthisfashionisunknown(Hale1981b).Thompson(1972)suggestedthattheminimumwaterdepthinstreamsusedbychumformigrationwas7in(18cm).Twotothreethousandeggsaredepositedbyfemalesinreddsdugatsitesthatareusuallyclearlyidentifiedwithareasofwaterupwelling.Pipereta1.(1982)indicateapproximately1100TUs(F)arerequiredforhatchingand1450foremergence,basedonstudiesthroughoutthespeciesrange(Table1.1-3).WangaardandBerger(1983),usingSusitnastocks,indicatedrelationshipsbetweentemperatureandincubationrateforhatchingandcompleteyolkabsorption(usuallyoccurringatemergence)tobe:Rh=3.23+1.40(temperature)Ra=2.25+0.59(temperature)whereRh=developmentrateperday(x1000)tohatchingRa=developmentrateperday(x1000)tocompleteyolkadsorptionJuvenilesgenerallyemergefromgravelsofsloughsalongtheSusitnainMarch-May,peakinginApril.Thetimespentinthegravelbyeggsanda1evinsisatimeofheavymortality.Requirementsforintragrave1flow,dissolvedoxygen,andotherfactorswerestudiedindetail(Hale1981b).Survivalratefromeggstofryinnaturalstreamstypicallyaverageslessthan10%(Hale1981b).Mostchumsalmonfrybegintheirdownstreammigrationtotheoceansoonafteremergence.Theyemigratenocturnally,attemperaturesrangingfrom2to10°C,generallyremainingnearthesurfaceinmainchannels,withlittlefeedingactivityalongshore(McPhailandLindsey1970).Movementisacombinationofdisplacementbywatercurrentsandactiveswimming.IntheSusitna,frytrapcollectionsshowdownstreammigratingchumfrywellintothesummer(althoughindiminishingnumbersafterlateJune),withindividualshavinggrownbeyondthesizeofemergence[usuallyabout1.4in(35mm)].ChumfryapparentlyfeedandgrowinSusitnaRiversloughs,wheretheyarefoundfromApriltoAugust.AllscalesofreturningadultsexaminedintheSusitna,however,showedjuvenilesenteringtheoceanintheirfirstyear.ThebulkofthedietofAlaskanchumfryinfreshwaterconsistsofbenthicorganisms,chieflyaquaticinsectssuchaschironomidlarvae,mayflyandstonef1ynymphs,caddisflyandb1ackf1ylarvae(Bakkala1970;ADF&G1983c).Chumfrygenerallyavoidtemperaturesaboveabout59°F(15°C),preferring53.6to57.2°of(12-14°C)(Brett1952).Growthwilloccurintherange40to60.3°F(4.4-15.7°C)butisfastestbetween50.2and55.2°F(10.1and12.9°C)(McNeilandBailey1975).Predationisamajorsourceofmortalitytochumfryduringthedownstreammigrationperiod.CommonpredatorsofchumfryinotherNorthAmericanstreamsthatoccurintheSusitnaarerainbowtrout,DollyVarden,cohosalmonsmo1ts,sculpins,andpredaceousbirdssuchaskingfishersandmergansers.PinkSalmon(Oncorhynchusgorbuscha)ThisspeciesisthesmallestbutmostabundantofthePacificsalmon,usuallyonly3to5lb(1.4-2.3kg)atmaturity,reaching10lb(4.5kg)maximum.Itmaturesintwoyears(15months1-15speciesisfound2000mi(3200km)fromthesea.Runsofchumaremarkedbywideyearlyfluctuationsinnumbers,andinpartofitsrangeithasdistinctsummerandfallforms.Itgenerallymaturesat4to5yearsofage,whenitentersriversinJulytoDecember.Youngmigrateoutofspawningriverssoonafteremergingfromredds(within1monthincoastalsitesbutupto3monthslaterinAlaskarivers)andmostofthelifeisspentinthesea(Bakka1a1970,Hale1981c).SusitnaRiverchumenterfreshwaterbetweenearlyJulyandmid-Septemberinrunsthatmaynumberabout400,000fish(1981and1982estimateswere283,000and458,000,respectively)(Figure1.1-7).PeakmigrationpastSunshineStationisinearlyAugust.TheYentnaaccountedforabout28,000fishofthetotalin1982(Figure1.1-4).Migrantsareprimarilyfour-year-01dfish,althoughthree-andfive-year-01dsrepresentabout15%.Considerablemillingintheriver,tributarymouths,andthemouthofDevilCanyonseemscharacteristicbeforefishseekspawningsites,mostlyinsloughs.Afewmainchannelandsidechannelspawningsites(10in1982)wereidentified,allabovetheChulitnaconfluence.Chumspawninthesamegeneralsloughareasandatthesametime(mid-Augusttomid-September)assockeye.Tributariesarealsoutilized,mainlyIndianRiver,FourthofJulyCreek,andPortageCreek,indecreasingorderofimportance.Temperaturessuitableformigrationrangefromabout8to14°C,withchangesinthisrangehavinglittleinfluenceonupstreammigration(Hale1981b).ChumsalmonhavelessabilitytosurmountrapidsandwaterfallsthanotherspeciesofPacificsalmon(ScottandCrossman1973).Waterflowsofabout2.5mlsareneartheupperlimitofsustainedswimmingspeed(Thompson1972).Adultchumswereobservedtravelingupstreaminshallowriffleswiththeupperpartoftheirbodiesabovewater,butthedistancethatcouldbecoveredinthisfashionisunknown(Hale1981b).Thompson(1972)suggestedthattheminimumwaterdepthinstreamsusedbychumformigrationwas7in(18cm).Twotothreethousandeggsaredepositedbyfemalesinreddsdugatsitesthatareusuallyclearlyidentifiedwithareasofwaterupwelling.Pipereta1.(1982)indicateapproximately1100TUs(F)arerequiredforhatchingand1450foremergence,basedonstudiesthroughoutthespeciesrange(Table1.1-3).WangaardandBerger(1983),usingSusitnastocks,indicatedrelationshipsbetweentemperatureandincubationrateforhatchingandcompleteyolkabsorption(usuallyoccurringatemergence)tobe:Rh=3.23+1.40(temperature)Ra=2.25+0.59(temperature)whereRh=developmentrateperday(x1000)tohatchingRa=developmentrateperday(x1000)tocompleteyolkadsorptionJuvenilesgenerallyemergefromgravelsofsloughsalongtheSusitnainMarch-May,peakinginApril.Thetimespentinthegravelbyeggsanda1evinsisatimeofheavymortality.Requirementsforintragrave1flow,dissolvedoxygen,andotherfactorswerestudiedindetail(Hale1981b).Survivalratefromeggstofryinnaturalstreamstypicallyaverageslessthan10%(Hale1981b).Mostchumsalmonfrybegintheirdownstreammigrationtotheoceansoonafteremergence.Theyemigratenocturnally,attemperaturesrangingfrom2to10°C,generallyremainingnearthesurfaceinmainchannels,withlittlefeedingactivityalongshore(McPhailandLindsey1970).Movementisacombinationofdisplacementbywatercurrentsandactiveswimming.IntheSusitna,frytrapcollectionsshowdownstreammigratingchumfrywellintothesummer(althoughindiminishingnumbersafterlateJune),withindividualshavinggrownbeyondthesizeofemergence[usuallyabout1.4in(35mm)].ChumfryapparentlyfeedandgrowinSusitnaRiversloughs,wheretheyarefoundfromApriltoAugust.AllscalesofreturningadultsexaminedintheSusitna,however,showedjuvenilesenteringtheoceanintheirfirstyear.ThebulkofthedietofAlaskanchumfryinfreshwaterconsistsofbenthicorganisms,chieflyaquaticinsectssuchaschironomidlarvae,mayflyandstonef1ynymphs,caddisflyandb1ackf1ylarvae(Bakkala1970;ADF&G1983c).Chumfrygenerallyavoidtemperaturesaboveabout59°F(15°C),preferring53.6to57.2°of(12-14°C)(Brett1952).Growthwilloccurintherange40to60.3°F(4.4-15.7°C)butisfastestbetween50.2and55.2°F(10.1and12.9°C)(McNeilandBailey1975).Predationisamajorsourceofmortalitytochumfryduringthedownstreammigrationperiod.CommonpredatorsofchumfryinotherNorthAmericanstreamsthatoccurintheSusitnaarerainbowtrout,DollyVarden,cohosalmonsmo1ts,sculpins,andpredaceousbirdssuchaskingfishersandmergansers.PinkSalmon(Oncorhynchusgorbuscha)ThisspeciesisthesmallestbutmostabundantofthePacificsalmon,usuallyonly3to5lb(1.4-2.3kg)atmaturity,reaching10lb(4.5kg)maximum.Itmaturesintwoyears(15months 1-16SPAWNINGINSLOUGHS(SOMEMAINCHANNEL)ADULTNUMBERS1981-263,0001982-430,000ADULTTIMINGJULYAUG,...~...ADULTNUMBERS1981-13,1001982-29,500"'-------1SOMETRIBUTARYSPAWNINGJUVENILEDUTMIGRATIDNINFIRSTSUMMERADULTSJULY-LATESEPT.(3-5YEARSOLD)1981-283,00019B2-458,OooCHUMSALMONADULTSNUMBERS1981-20,8001982-49,000Figure1.1-7.Chumsalmon(Oncorhynchusketa)-GeneralizedLifeCycleintheSusitnaRiverDrainage.1-16SPAWNINGINSLOUGHS(SOMEMAINCHANNEL)ADULTNUMBERS1981-263,0001982-430,000ADULTTIMINGJULYAUG,...~...ADULTNUMBERS1981-13,1001982-29,500"'-------1SOMETRIBUTARYSPAWNINGJUVENILEDUTMIGRATIDNINFIRSTSUMMERADULTSJULY-LATESEPT.(3-5YEARSOLD)1981-283,00019B2-458,OooCHUMSALMONADULTSNUMBERS1981-20,8001982-49,000Figure1.1-7.Chumsalmon(Oncorhynchusketa)-GeneralizedLifeCycleintheSusitnaRiverDrainage. 1-17atsea),andhasgeneticallydistinctodd-yearandeven-yearrunsthatcanbeofgreatlydisproportionatesizes.Pinksarethesecondhighestinvaluetothecommercialfishery(aftersockeye),eventhoughthecatchishigherinnumbers.Sportsmencatchthemintheocean,oftenconfusingthemwithyoungofotherspecies.Thenativemaleatmaturitydevelopsalargehumponthebackinadditiontothehookedsnout,leadingtocolloquialnames(e.g.,humpie).ItrangesfromCaliforniatoKoreaandJapan.MostabundantinAsianwater,itiswidelydistributedincoastalAlaska.Streamsusedforspawningrangefromextremelysmall,shortcoastalstreamstotributariesoflargeriversystems.PinksalmonentertheSusitnaRiversystemtospawninearlyJulythroughearlySeptember(Figure1.1-8).The1981and1982runsamountedtoapproximately86,000and890,000fish,respectively,ofwhichapproximatelyone-halfwentintotheYentnadrainage(Figure1.1-4).ThemigrationpeakedsharplynearAugust1.About73,000(8%)oftheSusitnarunpassedtheTalkeetnastationand59,000(7%)passedCurryin1982,indicatingthatnumerouspinksusetheChulitnaandTalkeetnariversaswellastheupperSusitna.ThemajorityofpinksalmonenteringtheTalkeetnatoDevilCanyonreachspawningtributaries,althoughseveralsloughsaccountforaboutone-sixthoftheescapement.Onemainstemspawningsitewasidentifiedin1982.MostusedtributariesincludeIndianRiver(26%),FourthofJulyCreek(25%),LaneCreek(22%),andPortageCreek(6%).Temperatureappearsnottobeacriticalfactorinupstreammigration,occurringgenerallyfrom45to60°F(7.3to15.5°C)(Bell1973).Althoughdepthsof18cmareconsideredmininumforextendedmigration(Thompson1972),pinksalmonhavebeenobservedpassingovershallowriffleslessthan9cmdeep(Wilsonetale1981).Thefemalepinksalmondepositsbetween800and2000eggsinaredd(dependingonfishsize)excavatedingravel.Watertemperaturesassociatedwithspawningwerestudiedextensively(Kreuger1981a)andthereisageneralpatternofacceptabletemperaturesthatrangefrom45to55°F(7.2-12.8°C).Temperaturesuptoabout62.6°F(17°C)wereapparentlyusedwhennecessary.Pinksalmonseemtoripenandspawnassummertemperaturesareindecline.Watercurrentsof1to26ft/s(0.3-0.8m/s)orsignificantupwellingwaterseemtoberequired,withdepthsof0.7to1.6ft(0.2-0.5m)whennotcrowded(Krueger1981a).AccordingtoPiperetale(1982),about900TUs(F)arerequiredforeggstohatchand1450foremergence(Table1.1-3).SustantialmortalityofpinksalmoneggsandalevinswasdocumentedinselectedreachesofstreamsinAlaskaandBritishColumbia(Krueger1981a).Mostmortalityseemstobeintheeggstage.Sometimesexceeding75%(occasionally90%),thismortalityappearstobethemajorlimitationtoproduction.Extremetemperatures[beyondtherange40to56°F(4.4-13.3°C)]havebeenimplicated,althoughlaterdevelopmentalstagestoleratecolderwater.PinksalmonfryintheSusitnaemergeassacfryduringMarch,andremainintheriversystemforonlyashortperiodoftime.ThemajoroutmigrationappearstobecompletebyJune;nofryhavebeenfoundaslateastheendofJuly.Thespeciesgenerallyutilizesmainchannels,doesnotoftenentershallows,emigratesnocturnally,andhidesinrivergravelbyday(McPhailandLindsey1970).Inturbidwaters,movementmaybethroughouttheday(Krueger1981a).Becausefreshwaterresidenceissoshort,therehavebeenfewattemptstodefinephysiologicalrequirementsofoutmigrants.1.1.2.2OtherAnadromousSpeciesEulachon(Thaleichthyspacificus)Theeulachon,oftencalled"hooligan"inAlaska,isasmall,slender,anadromoussmeltthatseldomexceeds12in(30cm)inlength.Itconstitutesasmallbutimportantfisheryasitishighlyesteemedasafood.Sportsmenandnativepeoplesdipnetfishfromthedenselyschooledspawningruns.Itspendsmostofitstimeinmarinewaters,butitentersfreshwaterstreamsfromnorthernCaliforniatotheBeringSeatospawnfromMarchtoJune.Eulachonmatureatseaafter2to3yearsinthesouthorthree(about75%)orfour(about25%)yearsinAlaska.TheyentertheSusitnaintwodistinctsruns(basedon1982samplingonly),oneinmid-MayandtheotherinearlyJune(Figure1.1-9).Thesecondrunisthelarger(4.5times).Initiationofobservedspawningrunsin1982coincidedwithfirstice-freeconditionsintheSusitnamainchannels,buttherewaslittlecorrelationwithtidesortemperaturechanges.Thespawningmigrationentersthelower60mi(96km)oftheriver(includingthelowerYentna)andfishspawnwithinafewdaysattemperaturesof37.4to49.1oF(3.0-9.5°C).Althoughmanyeulachondieafterspawning,asizablenumberofspawned-outadultsintheSusitnareturntotheocean(itisunclearwhetherthereisrepeatspawning).Spawningoccursinthewatercolumnoverriffleareasoroffcutbanksoverloosegravelorsand.Theeggs,whichmayreach25,000inasinglefemale,areadhesive,stickingtosandorothermaterialandhatchingintwotothreeweeks.Juvenileeulachonfeedonplanktoniccrustaceansandmoveoutofthespawningriversandintoestuariesduringtheirfirstspring.1-17atsea),andhasgeneticallydistinctodd-yearandeven-yearrunsthatcanbeofgreatlydisproportionatesizes.Pinksarethesecondhighestinvaluetothecommercialfishery(aftersockeye),eventhoughthecatchishigherinnumbers.Sportsmencatchthemintheocean,oftenconfusingthemwithyoungofotherspecies.Thenativemaleatmaturitydevelopsalargehumponthebackinadditiontothehookedsnout,leadingtocolloquialnames(e.g.,humpie).ItrangesfromCaliforniatoKoreaandJapan.MostabundantinAsianwater,itiswidelydistributedincoastalAlaska.Streamsusedforspawningrangefromextremelysmall,shortcoastalstreamstotributariesoflargeriversystems.PinksalmonentertheSusitnaRiversystemtospawninearlyJulythroughearlySeptember(Figure1.1-8).The1981and1982runsamountedtoapproximately86,000and890,000fish,respectively,ofwhichapproximatelyone-halfwentintotheYentnadrainage(Figure1.1-4).ThemigrationpeakedsharplynearAugust1.About73,000(8%)oftheSusitnarunpassedtheTalkeetnastationand59,000(7%)passedCurryin1982,indicatingthatnumerouspinksusetheChulitnaandTalkeetnariversaswellastheupperSusitna.ThemajorityofpinksalmonenteringtheTalkeetnatoDevilCanyonreachspawningtributaries,althoughseveralsloughsaccountforaboutone-sixthoftheescapement.Onemainstemspawningsitewasidentifiedin1982.MostusedtributariesincludeIndianRiver(26%),FourthofJulyCreek(25%),LaneCreek(22%),andPortageCreek(6%).Temperatureappearsnottobeacriticalfactorinupstreammigration,occurringgenerallyfrom45to60°F(7.3to15.5°C)(Bell1973).Althoughdepthsof18cmareconsideredmininumforextendedmigration(Thompson1972),pinksalmonhavebeenobservedpassingovershallowriffleslessthan9cmdeep(Wilsonetale1981).Thefemalepinksalmondepositsbetween800and2000eggsinaredd(dependingonfishsize)excavatedingravel.Watertemperaturesassociatedwithspawningwerestudiedextensively(Kreuger1981a)andthereisageneralpatternofacceptabletemperaturesthatrangefrom45to55°F(7.2-12.8°C).Temperaturesuptoabout62.6°F(17°C)wereapparentlyusedwhennecessary.Pinksalmonseemtoripenandspawnassummertemperaturesareindecline.Watercurrentsof1to26ft/s(0.3-0.8m/s)orsignificantupwellingwaterseemtoberequired,withdepthsof0.7to1.6ft(0.2-0.5m)whennotcrowded(Krueger1981a).AccordingtoPiperetale(1982),about900TUs(F)arerequiredforeggstohatchand1450foremergence(Table1.1-3).SustantialmortalityofpinksalmoneggsandalevinswasdocumentedinselectedreachesofstreamsinAlaskaandBritishColumbia(Krueger1981a).Mostmortalityseemstobeintheeggstage.Sometimesexceeding75%(occasionally90%),thismortalityappearstobethemajorlimitationtoproduction.Extremetemperatures[beyondtherange40to56°F(4.4-13.3°C)]havebeenimplicated,althoughlaterdevelopmentalstagestoleratecolderwater.PinksalmonfryintheSusitnaemergeassacfryduringMarch,andremainintheriversystemforonlyashortperiodoftime.ThemajoroutmigrationappearstobecompletebyJune;nofryhavebeenfoundaslateastheendofJuly.Thespeciesgenerallyutilizesmainchannels,doesnotoftenentershallows,emigratesnocturnally,andhidesinrivergravelbyday(McPhailandLindsey1970).Inturbidwaters,movementmaybethroughouttheday(Krueger1981a).Becausefreshwaterresidenceissoshort,therehavebeenfewattemptstodefinephysiologicalrequirementsofoutmigrants.1.1.2.2OtherAnadromousSpeciesEulachon(Thaleichthyspacificus)Theeulachon,oftencalled"hooligan"inAlaska,isasmall,slender,anadromoussmeltthatseldomexceeds12in(30cm)inlength.Itconstitutesasmallbutimportantfisheryasitishighlyesteemedasafood.Sportsmenandnativepeoplesdipnetfishfromthedenselyschooledspawningruns.Itspendsmostofitstimeinmarinewaters,butitentersfreshwaterstreamsfromnorthernCaliforniatotheBeringSeatospawnfromMarchtoJune.Eulachonmatureatseaafter2to3yearsinthesouthorthree(about75%)orfour(about25%)yearsinAlaska.TheyentertheSusitnaintwodistinctsruns(basedon1982samplingonly),oneinmid-MayandtheotherinearlyJune(Figure1.1-9).Thesecondrunisthelarger(4.5times).Initiationofobservedspawningrunsin1982coincidedwithfirstice-freeconditionsintheSusitnamainchannels,buttherewaslittlecorrelationwithtidesortemperaturechanges.Thespawningmigrationentersthelower60mi(96km)oftheriver(includingthelowerYentna)andfishspawnwithinafewdaysattemperaturesof37.4to49.1oF(3.0-9.5°C).Althoughmanyeulachondieafterspawning,asizablenumberofspawned-outadultsintheSusitnareturntotheocean(itisunclearwhetherthereisrepeatspawning).Spawningoccursinthewatercolumnoverriffleareasoroffcutbanksoverloosegravelorsand.Theeggs,whichmayreach25,000inasinglefemale,areadhesive,stickingtosandorothermaterialandhatchingintwotothreeweeks.Juvenileeulachonfeedonplanktoniccrustaceansandmoveoutofthespawningriversandintoestuariesduringtheirfirstspring. Pinksalmon(Oncorhynchusgorbuscha)-GeneralizedLifeCycleintheSusitnaRiverDrainage.JULYAUGADULTNUMBERS1981-49,5001982-443,000JUVENILEOUTMIGRATIONBYJUNEAFTEREMERGENCEADULTNUMBERS1981-7001982-59,000ADULTSJULY-EARLYSEPT.2YEARSOLD1981-85,6001982-890,5001-18PINKSALMONADULTNUMBERS1981-2,3001982-73,000Figure1.1-8.Pinksalmon(Oncorhynchusgorbuscha)-GeneralizedLifeCycleintheSusitnaRiverDrainage.JULYAUGADULTNUMBERS1981-49,5001982-443,000JUVENILEOUTMIGRATIONBYJUNEAFTEREMERGENCEADULTNUMBERS1981-7001982-59,000ADULTSJULY-EARLYSEPT.2YEARSOLD1981-85,6001982-890,5001-18PINKSALMONADULTNUMBERS1981-2,3001982-73,000Figure1.1-8. 1-19EULACHONSPAWNINGINMAINSTEMANDLOWERYENTNAINRIFFLEAREASANDOFFCUTBANKS(FEWDAYSDURATION)ADULTSFIRSTRUN:MIDMAYSECONDRUN:EARLYJUNE(3-4YEARSOLD)SOMEADULTSRETURNTOOCEANAFTERSPAWNINGJUVENILEOUTMIGRATIONINFIRSTYEARADULTTIMING:SIMILARFORUPSTREAMANDDOWNSTREAMULJMAYJUNEFigure1.1-9.Eulachon(Thaleichthyspacificus)-GeneralizedLifeCycleandHabitatSuitabilityinthe$usitnaRiverDrainage.1-19EULACHONSPAWNINGINMAINSTEMANDLOWERYENTNAINRIFFLEAREASANDOFFCUTBANKS(FEWDAYSDURATION)ADULTSFIRSTRUN:MIDMAYSECONDRUN:EARLYJUNE(3-4YEARSOLD)SOMEADULTSRETURNTOOCEANAFTERSPAWNINGJUVENILEOUTMIGRATIONINFIRSTYEARADULTTIMING:SIMILARFORUPSTREAMANDDOWNSTREAMULJMAYJUNEFigure1.1-9.Eulachon(Thaleichthyspacificus)-GeneralizedLifeCycleandHabitatSuitabilityinthe$usitnaRiverDrainage. 1-20BeringCisco(Coregonuslaurettae)TheBeringciscoisawhitefishspeciesthatoccursintheArcticfromtheBeaufortSeatoCookInlet(Alt1973).ThespecieswasnotknowntoinhabittheSusitnaRiverdrainagepriortotheSusitnahydroelectricprojectstudiesin1980.InteriorandwesternAlaskapopulationsappeartocontainbothanadromousandfreshwaterresidentforms;intheSusitnatheyappeartobeanadromousandmigratetoareasprincipallybelowTalkeetna.Ithasonlyasmallfishery.SpawningmigrationsbeginsporaticallyinearlyAugustbutdonotpeakattheSusitnaRivermouthuntilearlySeptember(Figure1.1-10).ThepeakreachesSunshineStationinlateSeptember-earlyOctober.Theadultswerecapturedinfishwheelsoperatedprimarilyforsalmon.Thereisnoestimateoftotalpopulationsize.Migrantsrangedinagebetweenfourandsixyears(mostlyfive-year-olds),andscalesindicatedseawardemigrationofjuvenilesintheirfirstyear.Sizesweregenerally12.6to14in(32-36cm).SpawninghasbeenidentifiedatnumerousmainstemsitesandispresumedtooccurthroughoutthereachbetweenRM30andRM100.Spawningsubstratesconsistedofcoarsegravel.PeakspawningisinthesecondweekofOctober,withadultsoccupyingthespawningsitesfor15to20d.Afterspawning,theadultsreturntothesea.Contrarytoourunderstandingofthesituationinotherriversystems,Susitnastocksshowrepeatspawning.Otherthanrecognitionthatitoccursclosetothesouthernlimitofitsdistribution(implyingsensitivitytowatermuchwarmerthanitfindsintheSusitnacurrently),littleisknownofthehabitatrequirementsofthespecies.DollyVarden(Salvelinusmalma)TheDollyVardenisanimportantandsought-aftersportfish,butwhereitoccurstogetherwithsalmonthelargeadultsaresignificantpredatorsonsalmonfryandfingerlings.ItisacharthatisnotuniversallyrecognizedasdistinctfromtheanadromousArcticchar,Salvelinusalpinus(Morrow1980).BothanadromousandresidentDollyVardenoccurinAlaskasouthoftheAlaskaRange(Krueger1981b).TakentogetherwiththeArcticchar,the"species"occursthroughoutthenorthernlatitudes.IntheSusitnastudies,theDollyVardenhasbeentreatedasaresidentspecies.Thisdistinctionisunsettled,becausedownstreamofDevilCanyon(bothaboveandbelowtheChulitnaconfluence)adultswerecaughtinfishwheelsandjuvenilesinscooptraps,geardesignedtosampleupstreamanddownstreammigratingstagesrespectively,ofanadromousspecies.Thenumberscaughtweresmall,however,andtaggingstudiesyieldedfewreturns.UpstreamofDevilCanyon,moreclearlyresidentformsofthespeciesarewidelydistributedintributariesintheimpoundmentreach.Althoughnotwellstudied,theypresumablywinterintheSusitnaRivermainstem.SpawninggenerallyoccursbetweenSeptemberandNovemberinreddsconstructedbythefemaleinsidechannelsofriversormainchannelsofstreams.Afterspawning,one-halformoreofthemalesmaydie(presumablyasaresultofaggressivebehavior),whereasfemalemortalityisgenerallylessthan10%.Theymayspawnagaininfollowingyears.Overalllongevityis9to12yearsinsoutheastAlaska.DollyVardeneggs,1000to2000perfemale,aredepositedintheclearedgravelofareddmuchasaresalmoneggs.Developmenttakesplaceoverthewinterandrequiressomewhatover200datwintertemperatures.Thereislittleinformationavailableoneithertemperature-tolerancelimitsortemperature-dependentdevelopmentrates.Onemergence,DollyVardenfryoccupyrelativelyquietstreamreaches,staynearthebottomfeedingonbenthos,andoftenremainmotionlessingravelinterstices.Habitatselectionbyolder,presmoltDollyVardenisnotwelldocumented,buttheyappeartousealltypesofstreamhabitat.Thelargerfishbecomemoreorientedtowardpools.ResidentadultsintheSusitnatributariesoccupiedplungepoolhabitats.HumpbackWhitefish(Coregonuspidschian)AlthoughAlaskahasacomplexofthreecloselyrelatedspeciesofwhitefish,thosefoundintheSusitnaRiverweredeterminedthroughgillrakercountstobethehumpback.Theotherspecies,C.clupeaformis(lakewhitefish)andC.nelsoni(AlaskaWhitefish,notrecognizedasadistinctspeciesbytheAmericanFisheriesSociety),mayalsooccur.Thehumpbackwhitefish,unliketheotherspecies,isconsideredanadromous.Migrationhabitsvarywidelyindifferentriversystems,anditsstatusintheSusitnaisunclear.MostindividualsfoundintheSusitnastudyprogramwerecapturedinfishwheelsinthesummerseason,althoughotherswerecollectedatsloughandtributarymouths.SpawningmigrationsforthespeciestypicallybegininJune,withspawninginOctoberandNovember(Morrow1980).OccurrenceofafewindividualsaboveDevilCanyonsuggeststhattheremayberesidentaswellasmigratorystocks(orthatupstreamindividualsareoftheresidentspecies).Generally,thehumpbackwhitefishismostabundantintheTalkeetnatoCook-InletreachoftheSusitna.Fishrangedinagesfromtwotosevenyears,withage4predominant.Theenvironmentalrequirementsofthespeciesareknown.1-20BeringCisco(Coregonuslaurettae)TheBeringciscoisawhitefishspeciesthatoccursintheArcticfromtheBeaufortSeatoCookInlet(Alt1973).ThespecieswasnotknowntoinhabittheSusitnaRiverdrainagepriortotheSusitnahydroelectricprojectstudiesin1980.InteriorandwesternAlaskapopulationsappeartocontainbothanadromousandfreshwaterresidentforms;intheSusitnatheyappeartobeanadromousandmigratetoareasprincipallybelowTalkeetna.Ithasonlyasmallfishery.SpawningmigrationsbeginsporaticallyinearlyAugustbutdonotpeakattheSusitnaRivermouthuntilearlySeptember(Figure1.1-10).ThepeakreachesSunshineStationinlateSeptember-earlyOctober.Theadultswerecapturedinfishwheelsoperatedprimarilyforsalmon.Thereisnoestimateoftotalpopulationsize.Migrantsrangedinagebetweenfourandsixyears(mostlyfive-year-olds),andscalesindicatedseawardemigrationofjuvenilesintheirfirstyear.Sizesweregenerally12.6to14in(32-36cm).SpawninghasbeenidentifiedatnumerousmainstemsitesandispresumedtooccurthroughoutthereachbetweenRM30andRM100.Spawningsubstratesconsistedofcoarsegravel.PeakspawningisinthesecondweekofOctober,withadultsoccupyingthespawningsitesfor15to20d.Afterspawning,theadultsreturntothesea.Contrarytoourunderstandingofthesituationinotherriversystems,Susitnastocksshowrepeatspawning.Otherthanrecognitionthatitoccursclosetothesouthernlimitofitsdistribution(implyingsensitivitytowatermuchwarmerthanitfindsintheSusitnacurrently),littleisknownofthehabitatrequirementsofthespecies.DollyVarden(Salvelinusmalma)TheDollyVardenisanimportantandsought-aftersportfish,butwhereitoccurstogetherwithsalmonthelargeadultsaresignificantpredatorsonsalmonfryandfingerlings.ItisacharthatisnotuniversallyrecognizedasdistinctfromtheanadromousArcticchar,Salvelinusalpinus(Morrow1980).BothanadromousandresidentDollyVardenoccurinAlaskasouthoftheAlaskaRange(Krueger1981b).TakentogetherwiththeArcticchar,the"species"occursthroughoutthenorthernlatitudes.IntheSusitnastudies,theDollyVardenhasbeentreatedasaresidentspecies.Thisdistinctionisunsettled,becausedownstreamofDevilCanyon(bothaboveandbelowtheChulitnaconfluence)adultswerecaughtinfishwheelsandjuvenilesinscooptraps,geardesignedtosampleupstreamanddownstreammigratingstagesrespectively,ofanadromousspecies.Thenumberscaughtweresmall,however,andtaggingstudiesyieldedfewreturns.UpstreamofDevilCanyon,moreclearlyresidentformsofthespeciesarewidelydistributedintributariesintheimpoundmentreach.Althoughnotwellstudied,theypresumablywinterintheSusitnaRivermainstem.SpawninggenerallyoccursbetweenSeptemberandNovemberinreddsconstructedbythefemaleinsidechannelsofriversormainchannelsofstreams.Afterspawning,one-halformoreofthemalesmaydie(presumablyasaresultofaggressivebehavior),whereasfemalemortalityisgenerallylessthan10%.Theymayspawnagaininfollowingyears.Overalllongevityis9to12yearsinsoutheastAlaska.DollyVardeneggs,1000to2000perfemale,aredepositedintheclearedgravelofareddmuchasaresalmoneggs.Developmenttakesplaceoverthewinterandrequiressomewhatover200datwintertemperatures.Thereislittleinformationavailableoneithertemperature-tolerancelimitsortemperature-dependentdevelopmentrates.Onemergence,DollyVardenfryoccupyrelativelyquietstreamreaches,staynearthebottomfeedingonbenthos,andoftenremainmotionlessingravelinterstices.Habitatselectionbyolder,presmoltDollyVardenisnotwelldocumented,buttheyappeartousealltypesofstreamhabitat.Thelargerfishbecomemoreorientedtowardpools.ResidentadultsintheSusitnatributariesoccupiedplungepoolhabitats.HumpbackWhitefish(Coregonuspidschian)AlthoughAlaskahasacomplexofthreecloselyrelatedspeciesofwhitefish,thosefoundintheSusitnaRiverweredeterminedthroughgillrakercountstobethehumpback.Theotherspecies,C.clupeaformis(lakewhitefish)andC.nelsoni(AlaskaWhitefish,notrecognizedasadistinctspeciesbytheAmericanFisheriesSociety),mayalsooccur.Thehumpbackwhitefish,unliketheotherspecies,isconsideredanadromous.Migrationhabitsvarywidelyindifferentriversystems,anditsstatusintheSusitnaisunclear.MostindividualsfoundintheSusitnastudyprogramwerecapturedinfishwheelsinthesummerseason,althoughotherswerecollectedatsloughandtributarymouths.SpawningmigrationsforthespeciestypicallybegininJune,withspawninginOctoberandNovember(Morrow1980).OccurrenceofafewindividualsaboveDevilCanyonsuggeststhattheremayberesidentaswellasmigratorystocks(orthatupstreamindividualsareoftheresidentspecies).Generally,thehumpbackwhitefishismostabundantintheTalkeetnatoCook-InletreachoftheSusitna.Fishrangedinagesfromtwotosevenyears,withage4predominant.Theenvironmentalrequirementsofthespeciesareknown. ADULTSEARl YAUG.-EARl YSEPT.(4-6YEARSOLD)1-21BERINGCISCOADULTSRETURNTOSEAAFTERSPAWNING,TORETURNAGAINANOTHERYEARJUVENilEOUTMIGRATIONINSPRINGOFFIRSTYEAR....ALASKAFigure1.1-10.BeringCisco(Coregonuslaurettae)-GeneralizedLifeCycleintheSusitnaRiverDrainage.ADULTSEARl YAUG.-EARl YSEPT.(4-6YEARSOLD)1-21BERINGCISCOADULTSRETURNTOSEAAFTERSPAWNING,TORETURNAGAINANOTHERYEARJUVENilEOUTMIGRATIONINSPRINGOFFIRSTYEAR....ALASKAFigure1.1-10.BeringCisco(Coregonuslaurettae)-GeneralizedLifeCycleintheSusitnaRiverDrainage. 1-22ArcticLamprey(Lampetrajaponica)TheArcticlampreyisoneoffourlampreyspeciesthatoccurinAlaska.ItwasobservedintheSusitnaRiverduring1981.ThePacificlamprey,Lampetratridentata,ananadromousspeciesthatwasreportedtorangeintothelowerSusitnaRiver(Morrow1980),wasnotobservedduringSusitnainvestigations.SomepopulationsofArcticlampreyarecomposedofbothanadromousandfreshwaterforms.Itwasspeculatedthataportion(30%)oftheSusitnapopulationisanadromous,basedonanalysisoflengthfrequencies.Theanadromousformisparasitic;hostsincludeadultsalmon,trout,whitefish,ciscoes,suckers,burbot,andthreespinestickleback(Heard1966).Thefreshwaterformshavebeenreportedtobebothparasiticandnonparasitic.AchinooksmoltandalongnosesuckerwerecapturedintheSusitnain1982whileparasitized.Arcticlampreyspawnduringthespringandearlysummerinstreamsoflowtomoderateflow.Eggsdevelopintoalarval("ammocetes")stageandspendonetofouryearsburrowedintoasoftsubstancebeforetranformingintosmalllampreysandmigratingdownstream.Afteranindefiniteperiodinlargewaterbodiesorthesea,adultsmigrateupstreamtospawn.AdultArcticlampreywerefoundabundantlyatSustinaRivertributarymouthsbelowRM50.5;theyweremuchlessabundantaboveTalkeetna,buttherearelocalizedconcentrationsofbothadultsandammocetesinWhiskersandGashcreeks.Environmentalrequirementsofthespeciesarevirtuallyunknown.Inconnu(Stenodusleucichthys)Alsocalledsheefish,thisspeciesisamemberofthewhitefishgroupofsalmonidae.ItmigratesintothefreshwaterportionsofestuariesinAlaskaandnorthernCanadainJuneandJuly.Itistheonlyfish-eatingwhitefishinNorthAmerica,andisaprizedgamefishthatoftenreachesover10lb(4.5kg)andover20yearsofage.ItwasnotrecordedintheSusitnastudies,butitislikelyfoundinsomeofthestreamstobeaffectedbytheproject.1.1.3.ResidentSpeciesArcticGrayling(Thymallusarcticus)TheArcticgraylingisastrikinggamefish,highlyprizedforitsbeauty.ThespeciesoccursinrelictorintroducedpopulationsinColorado,Montana,Wyoming,Idaho,andUtah,butthemostproductiveNorthAmericanpopulationsareinAlaskaandtheCanadianNorthwest.ThespeciesisbothalakeandariverfishovermuchofAlaska.Unliketrout,graylingroveinschools,whichareoftenseencruisinginsearchoffood.Arcticgraylingaresmall,withmostadultsrangingbetween2and3lb(0.9and1.4kg).Theirdistributionshowsadefinitepreferenceforclearwater(Krueger1981c).Ingeneral,ArcticgraylingarefoundthroughouttheSusitnaRiverbasinduringtheice-freemonths,andthespeciesisthemostsignificantfishofeconomicimportanceintheimpoundmentzone.TheyseemmostabundantintheSusitnaabovetheChulitnaconfluence,buttheyalsooccurdownstreamandindownstreamtributaries.TheSusitnaRivergraylingexhibitannualmovementsandlifecyclepatternstypicalofotherAlaskanpopulations(Krueger1981c).Theymoveoutofclear-watertributariesasfreeze-upapproachesinmid-SeptembertoOctobertooverwinterintheclear-watermainstem.Atthetimeofspringbreakup(endofMay),thelargestadultArcticgraylingmoveintotheclear-watertributariestospawninJuneandrearinthesummer.Theyappeartoreturntothesamestreamyearafteryear,basedontaggingandrecapturedataintheupperSusitna.Manyjuvenileslessthan7.9in(200mm)inhabitmainstemconfluenceareasoftributariesandsloughsinJulyandAugust,andsignificantnumbersofjuvenilesandsmalladultsusethemainsteminJunethroughAugust.Otherthanmovementsinandoutoftributaries,Arcticgraylingexhibitonlylocalmovements.Juvenilesalsoappeartooverwinterinthemainstem.Adultpopulationsizeswereestimatedineighttributaryhabitatlocationsin1982(Table1.1-4).ThelifespanofArcticgraylingisvariableacrossitsrange.AgeatmaturityinAlaskaisfourtonineyears,withthelongesttimebeingspentinthenorthernmostregions.MaximumagesoffishfromvariousTananaRiverdrainageswereabout11years(Tack1973);intheupperSusitnaitwas9years(ADF&G1983e).ThemostabundantageclassinupperSusitnatributariesisage5,withalengthof12.4in(315mm).Graylingspawninstreamsattemperaturesabove39.2°F(4°C)[usuallybelowabout50°F(10°C)],withcurrentvelocitieslessthan4.6ft/s(1.4m/s),atvaryingdepths,andoverrelativelysmall,unimbededgravelsabout1in(2.5cm)indiameter.Spawningwasobservedinshallowbackwaterareasoflakeinlets(Wojcik1954,1955)aswellasinstreams.Malesestablishterritoriesintowhichfemalesventureforspawning.Thereisnoredd,andfertilizedeggsfalltothebottomandadheretothesubstrateintheinterstitialspaces.Thereisnoparentalcareofeggs.Fecundityvariesgreatly;eggnumbershavebeenreportedrangingfrom2000to14,000per1-22ArcticLamprey(Lampetrajaponica)TheArcticlampreyisoneoffourlampreyspeciesthatoccurinAlaska.ItwasobservedintheSusitnaRiverduring1981.ThePacificlamprey,Lampetratridentata,ananadromousspeciesthatwasreportedtorangeintothelowerSusitnaRiver(Morrow1980),wasnotobservedduringSusitnainvestigations.SomepopulationsofArcticlampreyarecomposedofbothanadromousandfreshwaterforms.Itwasspeculatedthataportion(30%)oftheSusitnapopulationisanadromous,basedonanalysisoflengthfrequencies.Theanadromousformisparasitic;hostsincludeadultsalmon,trout,whitefish,ciscoes,suckers,burbot,andthreespinestickleback(Heard1966).Thefreshwaterformshavebeenreportedtobebothparasiticandnonparasitic.AchinooksmoltandalongnosesuckerwerecapturedintheSusitnain1982whileparasitized.Arcticlampreyspawnduringthespringandearlysummerinstreamsoflowtomoderateflow.Eggsdevelopintoalarval("ammocetes")stageandspendonetofouryearsburrowedintoasoftsubstancebeforetranformingintosmalllampreysandmigratingdownstream.Afteranindefiniteperiodinlargewaterbodiesorthesea,adultsmigrateupstreamtospawn.AdultArcticlampreywerefoundabundantlyatSustinaRivertributarymouthsbelowRM50.5;theyweremuchlessabundantaboveTalkeetna,buttherearelocalizedconcentrationsofbothadultsandammocetesinWhiskersandGashcreeks.Environmentalrequirementsofthespeciesarevirtuallyunknown.Inconnu(Stenodusleucichthys)Alsocalledsheefish,thisspeciesisamemberofthewhitefishgroupofsalmonidae.ItmigratesintothefreshwaterportionsofestuariesinAlaskaandnorthernCanadainJuneandJuly.Itistheonlyfish-eatingwhitefishinNorthAmerica,andisaprizedgamefishthatoftenreachesover10lb(4.5kg)andover20yearsofage.ItwasnotrecordedintheSusitnastudies,butitislikelyfoundinsomeofthestreamstobeaffectedbytheproject.1.1.3.ResidentSpeciesArcticGrayling(Thymallusarcticus)TheArcticgraylingisastrikinggamefish,highlyprizedforitsbeauty.ThespeciesoccursinrelictorintroducedpopulationsinColorado,Montana,Wyoming,Idaho,andUtah,butthemostproductiveNorthAmericanpopulationsareinAlaskaandtheCanadianNorthwest.ThespeciesisbothalakeandariverfishovermuchofAlaska.Unliketrout,graylingroveinschools,whichareoftenseencruisinginsearchoffood.Arcticgraylingaresmall,withmostadultsrangingbetween2and3lb(0.9and1.4kg).Theirdistributionshowsadefinitepreferenceforclearwater(Krueger1981c).Ingeneral,ArcticgraylingarefoundthroughouttheSusitnaRiverbasinduringtheice-freemonths,andthespeciesisthemostsignificantfishofeconomicimportanceintheimpoundmentzone.TheyseemmostabundantintheSusitnaabovetheChulitnaconfluence,buttheyalsooccurdownstreamandindownstreamtributaries.TheSusitnaRivergraylingexhibitannualmovementsandlifecyclepatternstypicalofotherAlaskanpopulations(Krueger1981c).Theymoveoutofclear-watertributariesasfreeze-upapproachesinmid-SeptembertoOctobertooverwinterintheclear-watermainstem.Atthetimeofspringbreakup(endofMay),thelargestadultArcticgraylingmoveintotheclear-watertributariestospawninJuneandrearinthesummer.Theyappeartoreturntothesamestreamyearafteryear,basedontaggingandrecapturedataintheupperSusitna.Manyjuvenileslessthan7.9in(200mm)inhabitmainstemconfluenceareasoftributariesandsloughsinJulyandAugust,andsignificantnumbersofjuvenilesandsmalladultsusethemainsteminJunethroughAugust.Otherthanmovementsinandoutoftributaries,Arcticgraylingexhibitonlylocalmovements.Juvenilesalsoappeartooverwinterinthemainstem.Adultpopulationsizeswereestimatedineighttributaryhabitatlocationsin1982(Table1.1-4).ThelifespanofArcticgraylingisvariableacrossitsrange.AgeatmaturityinAlaskaisfourtonineyears,withthelongesttimebeingspentinthenorthernmostregions.MaximumagesoffishfromvariousTananaRiverdrainageswereabout11years(Tack1973);intheupperSusitnaitwas9years(ADF&G1983e).ThemostabundantageclassinupperSusitnatributariesisage5,withalengthof12.4in(315mm).Graylingspawninstreamsattemperaturesabove39.2°F(4°C)[usuallybelowabout50°F(10°C)],withcurrentvelocitieslessthan4.6ft/s(1.4m/s),atvaryingdepths,andoverrelativelysmall,unimbededgravelsabout1in(2.5cm)indiameter.Spawningwasobservedinshallowbackwaterareasoflakeinlets(Wojcik1954,1955)aswellasinstreams.Malesestablishterritoriesintowhichfemalesventureforspawning.Thereisnoredd,andfertilizedeggsfalltothebottomandadheretothesubstrateintheinterstitialspaces.Thereisnoparentalcareofeggs.Fecundityvariesgreatly;eggnumbershavebeenreportedrangingfrom2000to14,000per 1-23Table1.1-4.ArcticGraylingPopuYationEstimatesbyTributaryHabitatEvaluationLocation,ProposedImpoundmentAreas,1982Popu1ationt1Confidencet2Gray1ing/Gray1ing/LocationEstimateIntervalMileAcreOshetnaRiver24261483-4085110356GooseCreek949509-194379190JayCreek1592903-3071455101KosinaCreek55443792-8543123269WatanaCreek39251880-697332444DeadmanCreekt3734394-15021835273TsusenaCreekt41000743-1530FogCreekt4176115-369440Totals16,3469,819-28,016664t1Correctionfactorincluded.t295%.t3Inc1udesonlythatpartofDeadmanCreekbelowfalls.t41981estimates.Conversion:Toconvertfrommilestokilometers,multiplyby1.6;toconvertfromacrestohectares,multiplyby0.4047.Source:ADF&G(1983e).female.Eggdevelopmentoccursrapidly(13-32d),influencedprimarilybywatertemperature[e.g.,8 dat60°F(15.5°C;19daysat39to48.5°F(3.9-9.2°C).Survivaltothefrystageislow[6%wasestimatedbyKruse(1959)],withbettersurvivalforeggsthathatchwithintheprotectionofgravels.Newlyhatchedgraylingwereobservedinmid-Junebothaboveandbelowtheproposedimpoundmentelevation.Growthratesareextremelyvariableacrossitsrange,duetodifferencesinlengthofopenwater(growing)seasons,temperatures,andfoodsupplies.Youngareoftenfoundinshallowmarginsoflakesandstreamsandinotherlow-velocityzones.LargeconcentrationshavebeenfoundintheSusitnainearlysummerattributarymouthsandthroughoutthesummerinclear-watersloughsoffthemainstream.Noexperimentaldataareavailabletoquantifygrowthratesatdifferenttemperatures,buttolerancetestsshowjuvenilesabletowithstandtemperaturesthatexceed76°F(24.5°C)(LaPerrierandCarlson1973).Oldfisharelesstolerant,butaremoreabletomovetocoolerareas.Individualsinthefieldhavereached0.8to2.0in(20-50mm)forklengthbyJulyoftheirfirstyear.Arcticgraylingareopportunisticfeedersandconsumelargerpreyastheygrow.Youngfeedonzooplanktonandchironomidlarvae;adultsconsumeaquaticandterrestrialinsects.Olderfishmoveprogressivelyintomorerapidlyflowingwaterareas.Becausetheyspendsummersinsmallstreamsthatmayfreezesolidinwinter,Arcticgraylingrequireoverwinteringareas.Theytypicallyusedeeplakes,deeppoolsoflargerstreamsorrivers,ordeeperspring-fedstreams,allofwhichmaybequitedistantfromrearingareas.Migrationroutesarethereforeessentialforpopulationsuccess.RainbowTrout(Sa1mogairdneri)ThisnativeNorthAmericantroutishighonthelistofgamefishesoftheworld.ItsnaturalrangeisfromthemountainsofMexicototheAleutianIslands.Itmaybeanadromous(steelhead),feedingintheNorthPacificOcean,orapermanentresidentinfreshwater.Inthe'Susitnadrainage,rainbowtroutareresidentsthataredistributedthroughoutthesystembelowDevilCanyonbutaremostcommoninclear-watertributariesandsloughs.Theyusethemainstemintheclear-waterseasonfromSeptembertospringwhentheymovebackintotributariestospawn.Theyarerelativelynonmigratoryelsewhere,usingonlyshortreachesofriver(McPhailandLindsey1970),andappearfromtelemetrystudiestobesointheSusitna,also.Juvenilesrearintributaries,butsomearefoundinclear-watersloughs.RainbowtroutappeartobemoreabundantabovetheconfluenceoftheChulitnathanbelow.1-23Table1.1-4.ArcticGraylingPOPuYationEstimatesbyTributaryHabitatEvaluationLocation,ProposedImpoundmentAreas,1982Popu1ationt1Confidencet2Gray1ing/Gray1ing/LocationEstimateIntervalMileAcreOshetnaRiver24261483-4085110356GooseCreek949509-194379190JayCreek1592903-3071455101KosinaCreek55443792-8543123269WatanaCreek39251880-697332444DeadmanCreekt3734394-15021835273TsusenaCreekt41000743-1530FogCreekt4176115-369440Totals16,3469,819-28,016664t1correctionfactorincluded.t295%.t3Inc1udesonlythatpartofDeadmanCreekbelowfalls.t41981estimates.Conversion:Toconvertfrommilestokilometers,multiplyby1.6;toconvertfromacrestohectares,multiplyby0.4047.Source:ADF&G(1983e).female.Eggdevelopmentoccursrapidly(13-32d),influencedprimarilybywatertemperature[e.g.,8 dat60°F(15.5°C;19daysat39to48.5°F(3.9-9.2°C).Survivaltothefrystageislow[6%wasestimatedbyKruse(1959)],withbettersurvivalforeggsthathatchwithintheprotectionofgravels.Newlyhatchedgraylingwereobservedinmid-Junebothaboveandbelowtheproposedimpoundmentelevation.Growthratesareextremelyvariableacrossitsrange,duetodifferencesinlengthofopenwater(growing)seasons,temperatures,andfoodsupplies.Youngareoftenfoundinshallowmarginsoflakesandstreamsandinotherlow-velocityzones.LargeconcentrationshavebeenfoundintheSusitnainearlysummerattributarymouthsandthroughoutthesummerinclear-watersloughsoffthemainstream.Noexperimentaldataareavailabletoquantifygrowthratesatdifferenttemperatures,buttolerancetestsshowjuvenilesabletowithstandtemperaturesthatexceed76°F(24.5°C)(LaPerrierandCarlson1973).Oldfisharelesstolerant,butaremoreabletomovetocoolerareas.Individualsinthefieldhavereached0.8to2.0in(20-50mm)forklengthbyJulyoftheirfirstyear.Arcticgraylingareopportunisticfeedersandconsumelargerpreyastheygrow.Youngfeedonzooplanktonandchironomidlarvae;adultsconsumeaquaticandterrestrialinsects.Olderfishmoveprogressivelyintomorerapidlyflowingwaterareas.Becausetheyspendsummersinsmallstreamsthatmayfreezesolidinwinter,Arcticgraylingrequireoverwinteringareas.Theytypicallyusedeeplakes,deeppoolsoflargerstreamsorrivers,ordeeperspring-fedstreams,allofwhichmaybequitedistantfromrearingareas.Migrationroutesarethereforeessentialforpopulationsuccess.RainbowTrout(Sa1mogairdneri)ThisnativeNorthAmericantroutishighonthelistofgamefishesoftheworld.ItsnaturalrangeisfromthemountainsofMexicototheAleutianIslands.Itmaybeanadromous(steelhead),feedingintheNorthPacificOcean,orapermanentresidentinfreshwater.Inthe'Susitnadrainage,rainbowtroutareresidentsthataredistributedthroughoutthesystembelowDevilCanyonbutaremostcommoninclear-watertributariesandsloughs.Theyusethemainstemintheclear-waterseasonfromSeptembertospringwhentheymovebackintotributariestospawn.Theyarerelativelynonmigratoryelsewhere,usingonlyshortreachesofriver(McPhailandLindsey1970),andappearfromtelemetrystudiestobesointheSusitna,also.Juvenilesrearintributaries,butsomearefoundinclear-watersloughs.RainbowtroutappeartobemoreabundantabovetheconfluenceoftheChulitnathanbelow. 1-24Therainbowtroutisoneofthemoststudiedoffishspecies,anditsphysiologicalrequirementsarewellknown(howwellthedatarepresentSusitnastocksisuncertain).IntheregionthatwillbeaffectedbytheSusitnaproject,rainbowtroutoccurmostlyasadultsduringtheiroverwinteringperiod.LakeTrout(Sa1ve1inusnamaycush)Thelaketroutisalargechar,ofhistoricallylargeeconomicvalueinNorthAmerica,thatinhabitsdeep,clearlakesfromnorthernNewEnglandandtheGreatLakes,westwardacrossnorthernpartsoftheCanadianborderprovincesandinteriorAlaskaexcepttheYukondrainage.IntheupperSusitnadrainageitoccursasaresidentinSallyandDeadmanlakeswheretherearelimitedsportfisheries.SallyLakeiswithintheimpoundmentcontoursforWatanaReservoir.Throughmuchofitsrange,thelaketroutrequiresthermallystratifiedlakeswithoxygenatedhypo1imnia;inAlaskaitfindssufficientlycoolwaterclosetoshoreinshallows.Laketroutspawninthefallovergravelorrockybottoms.Nonestisbuiltalthoughthegeneralareaissweptclearofsilt.Incubationrequiresabout165datwintertemperaturesof39.2°F(4°C).Youngfishremainindeepwater;inhighlightintensitiesofshallowwater,theydevelopabnormally.Insectsandcrustaceansmakeupthedietofyoung,whileadultsfeedonfishsuchaswhitefish,burbot,scu1pinsoryoungsalmon,andtrout.AdultscapturedinSallyLakewerelargelyfive-year-01ds.Laketroutarehighlysusceptibletopredationbylampreys,andthedistributionofthisspeciesandtheseveralspeciesoflampreyarealmostmutuallyexclusive.Burbot(Lotalota,)Alsocalledling,theburbotistheonlymemberofthecodfishfamilyfoundinfreshwaterinNorthAmerica.Itsupportsalimitedsportfisherythroughoutitsrange,whichextendsfromNewEnglandandtheSusquehannaRiversystemintheeast,throughouttheHudsonBaydrainageandwestwardincludingtheColumbiaRiver.BurbotarefoundintheSusitnaRiverandthroughoutmostofAlaska(McLeanandDelaney1978).Usuallylessthan30in(76cm),theAlaskanformislargerandmayattainalengthof4.9ft(1.5m)andweigh661b(30kg).TheymaturebetweenthreeandsixyearsinAlaskaandmayliveatotalof15to20years(ages4-8weremostcommonintheSusitna).Burbotisacoldwaterspecies,usuallyfoundinlakeswhereitseeksdeep,coldwaterinsummer.Itoccursinbothswiftandsluggishstreamsandoftenbecomesabundantthere.Spawningtakesplaceundertheicebetweenmid-DecemberandApril,oversandorgravelsubstrate,inshallow1to4ft(0.3to1.3m)water,andatnight.Theburbotisavoraciousnocturnalpredator,consumingfishandlargerbenthicorganisms.Itisastrongcompetitorwithsa1monidsandeatslargenumbersofsa1monids,whitefish,andciscos.IntheSusitna,burbothavebeencaughtthroughouttheriverfromCoo~Inletthroughtheupperendoftheimpoundmentreach.Theywerecommonatalltributaryandsloughmouths.Taggingstudiessuggestedonlylimitedmovementsbyadults.JuvenilesOCcurinthemainstemandinsloughs.Duringlowflows,adultswererestrictedtodeepersloughsandsidechannels,buttheyenteredshallowerareasathighflows.Environmentalrequirements,otherthancoldwater,arepoorlyknown.Itsnocturnalbehaviorandpreferenceforturbidwaterinsummersuggestanegativeresponsetolight.RoundWhitefish(Prosopiumcy1indraceum)TheroundwhitefishisoneofthemostwidespreadandcommonfishspeciesinnorthernwatersofNorthAmerica.ItoccursfromNewEnglandacrosstheGreatLakes(exceptErie)andCanada(exceptthesouthernpartofthewesternprovinces)andthroughoutmostofAlaska(McPhailandLindsey1970,Hale1981c).InAlaskaitisusedtoalimitedextentbysubsistencefishermenandasmallsportsfishery,althoughithascommercialimportanceintheGreatLakesandintheUSSR.Despitesuchwidedistribution,itslifehistoryandenvironmentalrequirementsarepoorlyknown.Itisassumedtohavefairlywidehabitattolerances(Hale1981c).Ashallow-waterspecieswhenfoundindeeplakes,itappearstopreferclearwaterwithturbiditylevelsbelow15ppm.SamplingintheSusitnadrainagefound'itmostlyintributaries(neartributarymouths)andsloughs,althoughsignificantnumberswerealsocollectedinthemainsteminadultsalmonfishwhee1sanddownstreammigranttraps.Adultsspawninthefall(lateSeptemberthroughOctoberinAlaska)inshallow,graveledareasoflakeshoresorstreams.Thereisnomajormigration.Eggsarebroadcastoverthesubstrateandtheysettleintocrevicesinthegraveltoincubate.Fecundityusuallyrangesfrom2,000to14,000eggsperfemale;thereisnoparentalcare.EggshatchinAprilorMayattemperaturesfrom32to35.6°F(0-2°C),andthefryremainintheshelterofbottommaterials.Fryappeartodisperseafteraboutonemonthinthesamegeneralareasofstreamoccupiedbytheadults.Theroundwhitefishisabottomfeeder,consumingmostlybenthic1-24Therainbowtroutisoneofthemoststudiedoffishspecies,anditsphysiologicalrequirementsarewellknown(howwellthedatarepresentSusitnastocksisuncertain).IntheregionthatwillbeaffectedbytheSusitnaproject,rainbowtroutoccurmostlyasadultsduringtheiroverwinteringperiod.LakeTrout(Sa1ve1inusnamaycush)Thelaketroutisalargechar,ofhistoricallylargeeconomicvalueinNorthAmerica,thatinhabitsdeep,clearlakesfromnorthernNewEnglandandtheGreatLakes,westwardacrossnorthernpartsoftheCanadianborderprovincesandinteriorAlaskaexcepttheYukondrainage.IntheupperSusitnadrainageitoccursasaresidentinSallyandDeadmanlakeswheretherearelimitedsportfisheries.SallyLakeiswithintheimpoundmentcontoursforWatanaReservoir.Throughmuchofitsrange,thelaketroutrequiresthermallystratifiedlakeswithoxygenatedhypo1imnia;inAlaskaitfindssufficientlycoolwaterclosetoshoreinshallows.Laketroutspawninthefallovergravelorrockybottoms.Nonestisbuiltalthoughthegeneralareaissweptclearofsilt.Incubationrequiresabout165datwintertemperaturesof39.2°F(4°C).Youngfishremainindeepwater;inhighlightintensitiesofshallowwater,theydevelopabnormally.Insectsandcrustaceansmakeupthedietofyoung,whileadultsfeedonfishsuchaswhitefish,burbot,scu1pinsoryoungsalmon,andtrout.AdultscapturedinSallyLakewerelargelyfive-year-01ds.Laketroutarehighlysusceptibletopredationbylampreys,andthedistributionofthisspeciesandtheseveralspeciesoflampreyarealmostmutuallyexclusive.Burbot(Lotalota,)Alsocalledling,theburbotistheonlymemberofthecodfishfamilyfoundinfreshwaterinNorthAmerica.Itsupportsalimitedsportfisherythroughoutitsrange,whichextendsfromNewEnglandandtheSusquehannaRiversystemintheeast,throughouttheHudsonBaydrainageandwestwardincludingtheColumbiaRiver.BurbotarefoundintheSusitnaRiverandthroughoutmostofAlaska(McLeanandDelaney1978).Usuallylessthan30in(76cm),theAlaskanformislargerandmayattainalengthof4.9ft(1.5m)andweigh661b(30kg).TheymaturebetweenthreeandsixyearsinAlaskaandmayliveatotalof15to20years(ages4-8weremostcommonintheSusitna).Burbotisacoldwaterspecies,usuallyfoundinlakeswhereitseeksdeep,coldwaterinsummer.Itoccursinbothswiftandsluggishstreamsandoftenbecomesabundantthere.Spawningtakesplaceundertheicebetweenmid-DecemberandApril,oversandorgravelsubstrate,inshallow1to4ft(0.3to1.3m)water,andatnight.Theburbotisavoraciousnocturnalpredator,consumingfishandlargerbenthicorganisms.Itisastrongcompetitorwithsa1monidsandeatslargenumbersofsa1monids,whitefish,andciscos.IntheSusitna,burbothavebeencaughtthroughouttheriverfromCoo~Inletthroughtheupperendoftheimpoundmentreach.Theywerecommonatalltributaryandsloughmouths.Taggingstudiessuggestedonlylimitedmovementsbyadults.JuvenilesOCcurinthemainstemandinsloughs.Duringlowflows,adultswererestrictedtodeepersloughsandsidechannels,buttheyenteredshallowerareasathighflows.Environmentalrequirements,otherthancoldwater,arepoorlyknown.Itsnocturnalbehaviorandpreferenceforturbidwaterinsummersuggestanegativeresponsetolight.RoundWhitefish(Prosopiumcy1indraceum)TheroundwhitefishisoneofthemostwidespreadandcommonfishspeciesinnorthernwatersofNorthAmerica.ItoccursfromNewEnglandacrosstheGreatLakes(exceptErie)andCanada(exceptthesouthernpartofthewesternprovinces)andthroughoutmostofAlaska(McPhailandLindsey1970,Hale1981c).InAlaskaitisusedtoalimitedextentbysubsistencefishermenandasmallsportsfishery,althoughithascommercialimportanceintheGreatLakesandintheUSSR.Despitesuchwidedistribution,itslifehistoryandenvironmentalrequirementsarepoorlyknown.Itisassumedtohavefairlywidehabitattolerances(Hale1981c).Ashallow-waterspecieswhenfoundindeeplakes,itappearstopreferclearwaterwithturbiditylevelsbelow15ppm.SamplingintheSusitnadrainagefound'itmostlyintributaries(neartributarymouths)andsloughs,althoughsignificantnumberswerealsocollectedinthemainsteminadultsalmonfishwhee1sanddownstreammigranttraps.Adultsspawninthefall(lateSeptemberthroughOctoberinAlaska)inshallow,graveledareasoflakeshoresorstreams.Thereisnomajormigration.Eggsarebroadcastoverthesubstrateandtheysettleintocrevicesinthegraveltoincubate.Fecundityusuallyrangesfrom2,000to14,000eggsperfemale;thereisnoparentalcare.EggshatchinAprilorMayattemperaturesfrom32to35.6°F(0-2°C),andthefryremainintheshelterofbottommaterials.Fryappeartodisperseafteraboutonemonthinthesamegeneralareasofstreamoccupiedbytheadults.Theroundwhitefishisabottomfeeder,consumingmostlybenthic 1-25invertebratesinshallowstreamsandinshorezonesoflakes.InAlaskanwatersgenerallygrowtolessthan15.8in(40cm)forklengthandusuallyweighlessthan1(0.5kg),althoughspecimensupto20in(52cm)and3.3lb(1.5kg)havebeentaken.reachsexualmaturityataboutsixtoeightyearsinthenorth.ThreespineStickleback(Gasterosteusaculeatus)Thissmall,hardy,extremelywidespread(throughoutnorthernlatitudesofNorthAmericaandEurasia)fishoccursthroughoutcoastalareasofsouthernAlaskaandintolargeriversystems(Hale1981a).Ithasdistinctformsthatoccurinfreshwater(~.~.leiurus),marinewaters(G.a.trachurus)andinintermediatezones(G.a.semiarmatus).IntheSusitna,allthreeformscanbeexpected;althoughnodistinctionhasbeenmadeinidentificationbytheSusitnateamofADF&G,thefreshwaterformisthemostprobable.ThefarthestupstreamtheyhavebeencapturedisattheTalkeetnaStationwheretheyappearedinthedownstreammigranttrap.MoststicklebacksintheSusitnaappeartoberesidentslocatedintributarymouthsandsloughs.Thespecies'principaleconomicimportanceisasapredatoronsalmoneggsandasacompetitorwithyoungsalmonidsforinvertebratefoodresources.Sticklebackinturnarepreyforlargetrout,salmon,andnorthernpike.Agreatdealisknownabouttheenvironmentalrequirementsandreproductivebehaviorofthisspecies.BecauseofitshardinessithasbeenusedextensivelyinEuropeandNorthAmericaasalaboratoryorganism.HowcloselytherequirementsandbehavioroftheselaboratoryanimalsmatchAlaskanpopulationsispoorlyknown.SpawningintheSusitnabelowtheChulitnaconfluenceapparentlyoccursfromJunethroughJuly,withyoung0.6to0.8in(15-20mm)inlateJulytoearlyAugust.Thespeciesistolerantofawiderangeoftemperatures,althoughitsbeingnearthenorthernlimitofitsrangemayindicateasensitivityfortemperaturesmuchlowerthanthoseitalreadyexperiencedinthelowerSusitna.LongnoseSucker(Catostomuscatostomus)Thelongnosesucker,theonlyrepresentativeofthesuckerfamilyfoundinAlaska,isubiquitousandoccursinmostofthemainlanddrainages.ItiswidelydistributedfromAlaskatoMaine.Adeep,cold-waterspecies,ithaslittleeconomicvalue.Spawningusuallyoccursinspringaftericeout.Spawningruns(i.e.,movementfromlakesintoinletstreamsorfromdeeppoolsintoshallower,gravel-bottomedstreamareas)areinitiatedwhenwatertemperaturesexceed41°F(5°C).Longnosesuckerfeedalmostexclusivelyonbenthicinvertebratesbutwilloccasionallyingestliveordeadfisheggs.TheywerecollectedthroughoutthestudyareafromCookInlettotheupperreachesoftheimpoundmentarea.Theirenvironmentalrequirementsarepoorlyknown.SlimySculpin(Cottuscognatus)andOtherCottidsAllsculpinspeciescapturedintheSusitnaRiverhavebeengroupedtogether.Theslimysculpinisthemostcommonspecies,althoughtheremaybeothersnotyetpositivelyidentified.Mostsculpins(cottids)aresmallfishcharacterizedbylarge,flattenedheads,expansivepectoralfins,andahabitatamongrocksonstreamorlakebottoms.Theyhavedevelopedareputationinsalmonidwatersofpreyingoneggsandalevinsinredds,althoughtheyfeedprincipallyonbottominvertebrates.Theslimysculpinisacold-waterspeciesfoundthroughoutnorthernNorthAmerica,includingtheGreatLakes.IthasbeencollectedthroughouttheSusitnaRiverstudyareaandappearstopreferclear-watertributaries.Itsenvironmentalrequirementsarepoorlyunderstood,andmayvaryifthereareseveralspeciesrepresentedinthebasin.NorthernPike(Esoxlucius)Thispopular,circumpolargamefishoflakesandriversismostabundantinthezoneacrossNewYork,theGreakLakes,andNebraska.Ithasbeenstockedwidely,however,andisfoundinseveralinteriorlakesofAlaska.Itisalarge[upto20lb(or9kg)]voraciouspredatornotedforitslarge,toothymouthandelongatedshape.Itliesinclear-water,shallowweedbedswhereitskeeneyesightallowsittospotandattackpassingfishes.AlthoughnotcommonintheSusitnaprojectarea,itmayoccurinlakestobeaffectedbytheproject,andcouldbecomeestablishedinthenewreservoirs.Itusestributarystreamsorstreammouthsforspawninginearlyspringasicegoesout.MuchisknownabouttheenvironmentalrequirementsofthespecieswhichwouldbevaluableforpossiblemanagementintheSusitnaprojectarea.1.1.4HabitatUtilizationExceptwhereindicatedthebase-linedescriptionofutilizationoftheSusitnaRiveraquatichabitatpresentedbelowisbasedonExhibitE,Chapter3,Sec.2.2.2,andonreportsbyADF&Gforthe1980-1981fieldseason(ADF&G1981a-f,1982a)andthe1981-82fieldseason(ADF&G1983a-e).Thesereportscharacterize,onaseasonalbasis,theuseofhabitatby<' ~ ~ 9 ? G > J _ G d _1-25invertebratesinshallowstreamsandinshorezonesoflakes.InAlaskanwatersgenerallygrowtolessthan15.8in(40cm)forklengthandusuallyweighlessthan1(0.5kg),althoughspecimensupto20in(52cm)and3.3lb(1.5kg)havebeentaken.reachsexualmaturityataboutsixtoeightyearsinthenorth.ThreespineStickleback(Gasterosteusaculeatus)Thissmall,hardy,extremelywidespread(throughoutnorthernlatitudesofNorthAmericaandEurasia)fishoccursthroughoutcoastalareasofsouthernAlaskaandintolargeriversystems(Hale1981a).Ithasdistinctformsthatoccurinfreshwater(~.~.leiurus),marinewaters(G.a.trachurus)andinintermediatezones(G.a.semiarmatus).IntheSusitna,allthreeformscanbeexpected;althoughnodistinctionhasbeenmadeinidentificationbytheSusitnateamofADF&G,thefreshwaterformisthemostprobable.ThefarthestupstreamtheyhavebeencapturedisattheTalkeetnaStationwheretheyappearedinthedownstreammigranttrap.MoststicklebacksintheSusitnaappeartoberesidentslocatedintributarymouthsandsloughs.Thespecies'principaleconomicimportanceisasapredatoronsalmoneggsandasacompetitorwithyoungsalmonidsforinvertebratefoodresources.Sticklebackinturnarepreyforlargetrout,salmon,andnorthernpike.Agreatdealisknownabouttheenvironmentalrequirementsandreproductivebehaviorofthisspecies.BecauseofitshardinessithasbeenusedextensivelyinEuropeandNorthAmericaasalaboratoryorganism.HowcloselytherequirementsandbehavioroftheselaboratoryanimalsmatchAlaskanpopulationsispoorlyknown.SpawningintheSusitnabelowtheChulitnaconfluenceapparentlyoccursfromJunethroughJuly,withyoung0.6to0.8in(15-20mm)inlateJulytoearlyAugust.Thespeciesistolerantofawiderangeoftemperatures,althoughitsbeingnearthenorthernlimitofitsrangemayindicateasensitivityfortemperaturesmuchlowerthanthoseitalreadyexperiencedinthelowerSusitna.LongnoseSucker(Catostomuscatostomus)Thelongnosesucker,theonlyrepresentativeofthesuckerfamilyfoundinAlaska,isubiquitousandoccursinmostofthemainlanddrainages.ItiswidelydistributedfromAlaskatoMaine.Adeep,cold-waterspecies,ithaslittleeconomicvalue.Spawningusuallyoccursinspringaftericeout.Spawningruns(i.e.,movementfromlakesintoinletstreamsorfromdeeppoolsintoshallower,gravel-bottomedstreamareas)areinitiatedwhenwatertemperaturesexceed41°F(5°C).Longnosesuckerfeedalmostexclusivelyonbenthicinvertebratesbutwilloccasionallyingestliveordeadfisheggs.TheywerecollectedthroughoutthestudyareafromCookInlettotheupperreachesoftheimpoundmentarea.Theirenvironmentalrequirementsarepoorlyknown.SlimySculpin(Cottuscognatus)andOtherCottidsAllsculpinspeciescapturedintheSusitnaRiverhavebeengroupedtogether.Theslimysculpinisthemostcommonspecies,althoughtheremaybeothersnotyetpositivelyidentified.Mostsculpins(cottids)aresmallfishcharacterizedbylarge,flattenedheads,expansivepectoralfins,andahabitatamongrocksonstreamorlakebottoms.Theyhavedevelopedareputationinsalmonidwatersofpreyingoneggsandalevinsinredds,althoughtheyfeedprincipallyonbottominvertebrates.Theslimysculpinisacold-waterspeciesfoundthroughoutnorthernNorthAmerica,includingtheGreatLakes.IthasbeencollectedthroughouttheSusitnaRiverstudyareaandappearstopreferclear-watertributaries.Itsenvironmentalrequirementsarepoorlyunderstood,andmayvaryifthereareseveralspeciesrepresentedinthebasin.NorthernPike(Esoxlucius)Thispopular,circumpolargamefishoflakesandriversismostabundantinthezoneacrossNewYork,theGreakLakes,andNebraska.Ithasbeenstockedwidely,however,andisfoundinseveralinteriorlakesofAlaska.Itisalarge[upto20lb(or9kg)]voraciouspredatornotedforitslarge,toothymouthandelongatedshape.Itliesinclear-water,shallowweedbedswhereitskeeneyesightallowsittospotandattackpassingfishes.AlthoughnotcommonintheSusitnaprojectarea,itmayoccurinlakestobeaffectedbytheproject,andcouldbecomeestablishedinthenewreservoirs.Itusestributarystreamsorstreammouthsforspawninginearlyspringasicegoesout.MuchisknownabouttheenvironmentalrequirementsofthespecieswhichwouldbevaluableforpossiblemanagementintheSusitnaprojectarea.1.1.4HabitatUtilizationExceptwhereindicatedthebase-linedescriptionofutilizationoftheSusitnaRiveraquatichabitatpresentedbelowisbasedonExhibitE,Chapter3,Sec.2.2.2,andonreportsbyADF&Gforthe1980-1981fieldseason(ADF&G1981a-f,1982a)andthe1981-82fieldseason(ADF&G1983a-e).Thesereportscharacterize,onaseasonalbasis,theuseofhabitatby<' ~ ~ 9 ? G > J _ G d _ 1-26anadromousandresidentspecieswithinthestudyarea.Habitatutilizationisdiscussedbelowforthreereachesoftheriver:OshetnaRivertoDevilCanyon(RM236toRM152),DevilCanyontoTalkeetna(RM152toRM98),andTalkeetnatoCookInlet(RM98toRM0).ThecontinuumofhabitatsavailableintheSusitnaRivermaybegroupedintofourtypes:mainstem,sidechannel,slough,andtributarymouth.Thesizeandoccurrenceofthesehabitattypesrespond,oftendramatically,tochangesinmainstemdischarge.MainstemhabitatconsistsofthatportionoftheSusitnaRiverthatconveysstreamflowatalltimes.Bothsingle-andmultichannelreachesareincludedinthiscategory.Groundwaterandtributaryinflowaregenerallyminorcontributorstostreamflowwithinariversegment,althoughmajortributariesprovidemorethanone-halfoftheflowintheriverdownstreamfromTalkeetna.Side-channelhabitatconsistsofthoseportionsoftheSusitnaRiverthatnormallyconveystreamflowonlyduringthehigh-flow,open-waterseasonbutwhichbecomeappreciablydewateredduringperiodsoflowflow.Ingeneral,shallowerdepths,lowervelocities,andsmallerstreambedmaterialsoccurinsidechannelsthanoccurinthemainstem.However,thestreamflow,sediment,andthermalregimesofside-channelhabitatsresponddirectlytomainstemconditions.Tributaryandgroundwaterinflowmaypreventside-channelhabitatsfrombecomingcompletelydewateredatlowmainstemflows.Sloughsareoverflowchannelsthatconveyglacialmeltwaterfromthemainstemduringmoderateandhigh-flowperiodsandconveyclearwaterfromlocalrunoffandgroundwaterduringintermediateandlow-flowperiods.Thestreambedelevationinasloughisnotablyhigherattheupstreamentrancethanatthemouth,andsloughsoftenfunctionlikesmallstreamsystems.Aportionofthechannelineachslough,whichmayvaryinlengthfromseveralhundredtoseveralthousandfeet(nearonehundredtoathousandmetersormore),conveyswaterwithouttheinfluenceofthemainstembackwater.Thephysicalcharacteristicsofsloughhabitatappeartodependontheinteractionoffourprincipalfactors:thedischargeofthemainstemSusitnaRiver,surfacerunoffpatternsfromtheadjacentcatchmentarea,groundwaterflowcontributions,andiceprocesseswithinthemainstemriversystem.Thesefourprincipalfactorsinteracttovaryingdegreesduringdifferentportionsoftheyeartoprovideauniquehabitattype.Tributaryhabitatisnotdependentonmainstemriverconditionsthatexistatthetributarymouth.Thestreamflow, sediment,andthermalregimesreflecttheintegrationofthehydrology,geology,andclimatologyofthetributarydrainage.Atthemouthofmosttributariesthestageofthemainstemrivercausesabackwaterthatextendsintothetributary,andthetributaryflowcreatesaclear-waterplumealongthebankinthemainstem.1.1.4.1UpstreamofDevilCanyonThewaterresourcesandhabitatavailabilityoftheimpoundmentreachoftheSusitnaRiverarecharacterizedinAppendixA,Section2.1.1.Onlymainstemandtributaryhabitatoccurinthisreach.1.1.4.1.1MainstemHabitatAlthoughadultchinooksalmonweredocumentedforthefirsttimeatRM156.8in1982,nootheranadromousspecieshavebeenreportedinthemainstemSusitnaintheimpoundmentreach.CurrentopinionisthathydrauliccharacteristicsoftheSusitnaRiveratDevilCanyonactasabarriertoupstreamsalmonmovementduringhighflows.Sevenresidentspeciesoccurinthemainstem:arcticgrayling,10ngnosesucker,humpbackwhitefish,roundwhitefish,DollyVarden,burbot,andslimysculpin.Thelongnosesucker,roundwhitefish,andburbotoccuralmostexclusivelyinthemainstemnearthemouthsofthetributaries,areaswhichtheyappeartouseasyear-roundhabitat.Basedontaggingstudies,thearcticgraylingoccupymainstemlocationsmostlyinwinter.Theselocationsappeartoprovideprimaryoverwinteringhabitatandmigrationroutesbetweentributaries.1.1.4.1.2TributaryHabitatThereareeightmajortributariesintheimpoundmentreach:FogandTsusenacreeksintheDevilCanyonimpoundment;andDeadman,Watana,Kosina,Jay,andGoosecreeksandtheOshetnaRiverintheWatanaimpoundment.Atleasttworesidentspecies,arcticgraylingandcottids,occurintributaries.Otherspeciescapturednearthemouthsoftributariesprobablyalsousethetributariesperiodically.1-26anadromousandresidentspecieswithinthestudyarea.Habitatutilizationisdiscussedbelowforthreereachesoftheriver:OshetnaRivertoDevilCanyon(RM236toRM152),DevilCanyontoTalkeetna(RM152toRM98),andTalkeetnatoCookInlet(RM98toRM0).ThecontinuumofhabitatsavailableintheSusitnaRivermaybegroupedintofourtypes:mainstem,sidechannel,slough,andtributarymouth.Thesizeandoccurrenceofthesehabitattypesrespond,oftendramatically,tochangesinmainstemdischarge.MainstemhabitatconsistsofthatportionoftheSusitnaRiverthatconveysstreamflowatalltimes.Bothsingle-andmultichannelreachesareincludedinthiscategory.Groundwaterandtributaryinflowaregenerallyminorcontributorstostreamflowwithinariversegment,althoughmajortributariesprovidemorethanone-halfoftheflowintheriverdownstreamfromTalkeetna.Side-channelhabitatconsistsofthoseportionsoftheSusitnaRiverthatnormallyconveystreamflowonlyduringthehigh-flow,open-waterseasonbutwhichbecomeappreciablydewateredduringperiodsoflowflow.Ingeneral,shallowerdepths,lowervelocities,andsmallerstreambedmaterialsoccurinsidechannelsthanoccurinthemainstem.However,thestreamflow,sediment,andthermalregimesofside-channelhabitatsresponddirectlytomainstemconditions.Tributaryandgroundwaterinflowmaypreventside-channelhabitatsfrombecomingcompletelydewateredatlowmainstemflows.Sloughsareoverflowchannelsthatconveyglacialmeltwaterfromthemainstemduringmoderateandhigh-flowperiodsandconveyclearwaterfromlocalrunoffandgroundwaterduringintermediateandlow-flowperiods.Thestreambedelevationinasloughisnotablyhigherattheupstreamentrancethanatthemouth,andsloughsoftenfunctionlikesmallstreamsystems.Aportionofthechannelineachslough,whichmayvaryinlengthfromseveralhundredtoseveralthousandfeet(nearonehundredtoathousandmetersormore),conveyswaterwithouttheinfluenceofthemainstembackwater.Thephysicalcharacteristicsofsloughhabitatappeartodependontheinteractionoffourprincipalfactors:thedischargeofthemainstemSusitnaRiver,surfacerunoffpatternsfromtheadjacentcatchmentarea,groundwaterflowcontributions,andiceprocesseswithinthemainstemriversystem.Thesefourprincipalfactorsinteracttovaryingdegreesduringdifferentportionsoftheyeartoprovideauniquehabitattype.Tributaryhabitatisnotdependentonmainstemriverconditionsthatexistatthetributarymouth.Thestreamflow, sediment,andthermalregimesreflecttheintegrationofthehydrology,geology,andclimatologyofthetributarydrainage.Atthemouthofmosttributariesthestageofthemainstemrivercausesabackwaterthatextendsintothetributary,andthetributaryflowcreatesaclear-waterplumealongthebankinthemainstem.1.1.4.1UpstreamofDevilCanyonThewaterresourcesandhabitatavailabilityoftheimpoundmentreachoftheSusitnaRiverarecharacterizedinAppendixA,Section2.1.1.Onlymainstemandtributaryhabitatoccurinthisreach.1.1.4.1.1MainstemHabitatAlthoughadultchinooksalmonweredocumentedforthefirsttimeatRM156.8in1982,nootheranadromousspecieshavebeenreportedinthemainstemSusitnaintheimpoundmentreach.CurrentopinionisthathydrauliccharacteristicsoftheSusitnaRiveratDevilCanyonactasabarriertoupstreamsalmonmovementduringhighflows.Sevenresidentspeciesoccurinthemainstem:arcticgrayling,10ngnosesucker,humpbackwhitefish,roundwhitefish,DollyVarden,burbot,andslimysculpin.Thelongnosesucker,roundwhitefish,andburbotoccuralmostexclusivelyinthemainstemnearthemouthsofthetributaries,areaswhichtheyappeartouseasyear-roundhabitat.Basedontaggingstudies,thearcticgraylingoccupymainstemlocationsmostlyinwinter.Theselocationsappeartoprovideprimaryoverwinteringhabitatandmigrationroutesbetweentributaries.1.1.4.1.2TributaryHabitatThereareeightmajortributariesintheimpoundmentreach:FogandTsusenacreeksintheDevilCanyonimpoundment;andDeadman,Watana,Kosina,Jay,andGoosecreeksandtheOshetnaRiverintheWatanaimpoundment.Atleasttworesidentspecies,arcticgraylingandcottids,occurintributaries.Otherspeciescapturednearthemouthsoftributariesprobablyalsousethetributariesperiodically. 1-27Abundanceestimatesforgraylingfrom1982dataindicatethatinexcessof16,300graylinginhabitclear-watertributariesintheimpoundmentzoneduringthesummer.Althoughspawninghasnotbeenobservedintheimpoundmentzone,suitablespawninghabitat(sandygravel)doesexistinallofthetributariessampled,anditislikelythatspawningoccursinthelowerreachesofthesetributaries.GraylingfrywerefoundinthelowerreachesofWatanaCreek,indicatingthatspawninghadoccurrednearby.Graylingthathavecompletedspawningmoveupstreamintoareasthathavepool-typehabitatswheretheyremainthroughoutthesummer.1.1.4.2DevilCanyontoTalkeetnaThewaterresourcesandhabitatavailabilityoftheSusitnaRiverfromDevilCanyontoTalkeetnaarecharacterizedinAppendixA,Sec.2.1.2.1.1.4.2.1MainstemandSide-ChannelHabitatThemainstemandsidechannelsbetweenDevilCanyonandTalkeetnaareusedprimarilybyanadromousandresidentspeciesasamigrationalcorridorandoverwinteringarea.Theavailabilityandutilizationofmainstemaquatichabitatarediscussedbelowforvariousspeciesofcommercialandrecreationalimportance.FivespeciesofPacificsalmonwereobservedintheSusitnaRiverbetweenDevilCanyonandTalkeetna.StudiesindicatethatadultsalmonutilizethemainstemupstreamfromTalkeetnafromlatespringintothefallduringmigrationandspawningperiods.Useperiodsforadultsofeachspeciesare:Chinook--mid-JunethroughJuly;Sockeye--mid-Ju1ythroughmid-September;Coho--1ateJulythroughSeptember;Chum--1ateJulythroughmid-September;andPink--1ateJulythroughAugust.Relativeabundanceestimatesbasedon1981and1982escapementdataandpopulationestimatesaregiveninTable1.1-5foreachofthesalmonspeciesthatusethisreachoftheSusitnaRiverprimarilyasapassagewaytospawningareas.ThemainstemreachfromDevilCanyontoTalkeetnaservesasamigrationcorridorforarelativelysmallpercentageofthetotalSusitnaRiversalmonescapement(Figure1.1-4).Duringmigrationperiods,variousbehavioralanddistributionpatternsareassociatedwithcertaincharacteristicsofmainstemhabitat,includingwaterdepth,velocity,channelconfiguration,andlocation orabsenceofobstructions.Generally,passageofadultsalmonduringmigrationcorrespondswiththesummerhigh-flowseason.However,passageofadultsalmononadailybasis(measuredbyside-scansonar)indicatethatsalmonmovementsdecreaseduringperiodsofhighestflows[40,000ft3/s(68,000m3/min)]andincreaseasflowssubsidefollowingmajorflowevents.Itishypothesizedthatincreasedwatervelocitiesassociatedwithpeakflowsdiscouragepassageandencouragemilling.Radiote1ementryinvestigationandgi11nettingindicatethattheconfluenceoftheTalkeetna,Chulitna,andSusitnariversisamillingareaforchum,pink,coho,andchinookandthatsockeye,chum,coho,pink,andchinookmillinthemainstemonemile(1.6km)belowDevilCanyon.Chumwereobservedspawningat10sitesandcohoat4ofthe11mainstemspawningsitesidentifiedintheDevilCanyontoTalkeetnareachduring1982.Mainstemspawningappearedtoberestrictedbylackofsuitablespawningsubstrateandgroundwaterupwelling.Juvenilesalmonarealsopresentinthemainstematvarioustimesoftheyear.Periodsofuseandrelativeabundancein1981and1982areoutlinedbelow.Chinook--Duringthewinterfollowinghatchingtheprecedingspring,juvenilesweremostabundantinthemainstem.PriortoJune1throughtheendofJuly,age1+juvenileswereabundantastheywereobservedmovingdownstreaminthemainstem.Sockeye--In1982,sockeyejuvenilesmovedoutoftheDevilCanyontoTalkeetnareachasage0fish,primarilyduringJuneandJulyfollowinghatchinginspring1982.Coho--Duringwinter,cohoaremostabundantinthemainstem.lessabundantinthemainstemthanatthetributarymouths.inJune.DuringsummertheyareslightlyIn1982,out-migrationpeakedChum--Themajorityofthechumjuvenilesmigrateddownstreamasage0fishpriortoJuly1in1982.Pink--Studiestodate!lavecaughtfewpinkjuvenilesinthemainstem.1-27Abundanceestimatesforgraylingfrom1982dataindicatethatinexcessof16,300graylinginhabitclear-watertributariesintheimpoundmentzoneduringthesummer.Althoughspawninghasnotbeenobservedintheimpoundmentzone,suitablespawninghabitat(sandygravel)doesexistinallofthetributariessampled,anditislikelythatspawningoccursinthelowerreachesofthesetributaries.GraylingfrywerefoundinthelowerreachesofWatanaCreek,indicatingthatspawninghadoccurrednearby.Graylingthathavecompletedspawningmoveupstreamintoareasthathavepool-typehabitatswheretheyremainthroughoutthesummer.1.1.4.2DevilCanyontoTalkeetnaThewaterresourcesandhabitatavailabilityoftheSusitnaRiverfromDevilCanyontoTalkeetnaarecharacterizedinAppendixA,Sec.2.1.2.1.1.4.2.1MainstemandSide-ChannelHabitatThemainstemandsidechannelsbetweenDevilCanyonandTalkeetnaareusedprimarilybyanadromousandresidentspeciesasamigrationalcorridorandoverwinteringarea.Theavailabilityandutilizationofmainstemaquatichabitatarediscussedbelowforvariousspeciesofcommercialandrecreationalimportance.FivespeciesofPacificsalmonwereobservedintheSusitnaRiverbetweenDevilCanyonandTalkeetna.StudiesindicatethatadultsalmonutilizethemainstemupstreamfromTalkeetnafromlatespringintothefallduringmigrationandspawningperiods.Useperiodsforadultsofeachspeciesare:Chinook--mid-JunethroughJuly;Sockeye--mid-Ju1ythroughmid-September;Coho--1ateJulythroughSeptember;Chum--1ateJulythroughmid-September;andPink--1ateJulythroughAugust.Relativeabundanceestimatesbasedon1981and1982escapementdataandpopulationestimatesaregiveninTable1.1-5foreachofthesalmonspeciesthatusethisreachoftheSusitnaRiverprimarilyasapassagewaytospawningareas.ThemainstemreachfromDevilCanyontoTalkeetnaservesasamigrationcorridorforarelativelysmallpercentageofthetotalSusitnaRiversalmonescapement(Figure1.1-4).Duringmigrationperiods,variousbehavioralanddistributionpatternsareassociatedwithcertaincharacteristicsofmainstemhabitat,includingwaterdepth,velocity,channelconfiguration,andlocation orabsenceofobstructions.Generally,passageofadultsalmonduringmigrationcorrespondswiththesummerhigh-flowseason.However,passageofadultsalmononadailybasis(measuredbyside-scansonar)indicatethatsalmonmovementsdecreaseduringperiodsofhighestflows[40,000ft3/s(68,000m3/min)]andincreaseasflowssubsidefollowingmajorflowevents.Itishypothesizedthatincreasedwatervelocitiesassociatedwithpeakflowsdiscouragepassageandencouragemilling.Radiote1ementryinvestigationandgi11nettingindicatethattheconfluenceoftheTalkeetna,Chulitna,andSusitnariversisamillingareaforchum,pink,coho,andchinookandthatsockeye,chum,coho,pink,andchinookmillinthemainstemonemile(1.6km)belowDevilCanyon.Chumwereobservedspawningat10sitesandcohoat4ofthe11mainstemspawningsitesidentifiedintheDevilCanyontoTalkeetnareachduring1982.Mainstemspawningappearedtoberestrictedbylackofsuitablespawningsubstrateandgroundwaterupwelling.Juvenilesalmonarealsopresentinthemainstematvarioustimesoftheyear.Periodsofuseandrelativeabundancein1981and1982areoutlinedbelow.Chinook--Duringthewinterfollowinghatchingtheprecedingspring,juvenilesweremostabundantinthemainstem.PriortoJune1throughtheendofJuly,age1+juvenileswereabundantastheywereobservedmovingdownstreaminthemainstem.Sockeye--In1982,sockeyejuvenilesmovedoutoftheDevilCanyontoTalkeetnareachasage0fish,primarilyduringJuneandJulyfollowinghatchinginspring1982.Coho--Duringwinter,cohoaremostabundantinthemainstem.lessabundantinthemainstemthanatthetributarymouths.inJune.DuringsummertheyareslightlyIn1982,out-migrationpeakedChum--Themajorityofthechumjuvenilesmigrateddownstreamasage0fishpriortoJuly1in1982.Pink--Studiestodate!lavecaughtfewpinkjuvenilesinthemainstem. Table 1.1-5.Side-scan Sonar Counts of Salmon Migrating Past Yentna Station and Peterson Population Estimates and Corresponding 95%Confidence Intervals of Salmon Migrating to Sunshine.Talkeetna and Curry Stations.1981-1982 Station Chinook Sockeye Coho Chum Pink 1981 1982 1981 1982 1981 1982 1981 1982 1981 1982 Yentna Station ----139.000 114.000 17.000 34.100 19.800 27.800 36.100 447.000 Sunshine Station No.of Fish --49.600 133.000 151.000 19.800 45.700 263.000 430.000 49.500 443.000 ...... I 95%Confidence 45.000 120.000 139.000 18.000 42.000 235.000 408.000 46.400 407.000 N OJ Interval 55.100 150.000 167.000 22.000 50.300 298.000 456.000 53.100 487.000 Talkeetna Station No.of Fish 10.900 4.800 3.100 3.300 5.100 20.800 49.100 2.300 73.000 95%Confidence 8.300 4.300 2.800 2.800 4.300 18.400 45.200 1.900 70.500 Interval 12.500 5.400 3.500 6.200 6.200 22.800 53.800 2.943 75.800 Curry Stat i on No.of Fish 11.300 2.800 1.300 1.100 2.400 13.100 29.400 1,000 59,000 95%Confidence 8,300 2.600 1,100 7,090 1,800 11 ,800 26,700 700 53,600 Interval 16.000 3.100 1,500 2.500 3,800 14,600 32.700 2.100 65,300 Source:Exhibit E.Table E.3.5. Table 1.1-5.Side-scan Sonar Counts of Salmon Migrating Past Yentna Station and Peterson Population Estimates and Corresponding 95%Confidence Intervals of Salmon Migrating to Sunshine.Talkeetna and Curry Stations.1981-1982 Station Chinook Sockeye Coho Chum Pink 1981 1982 1981 1982 1981 1982 1981 1982 1981 1982 Yentna Station 139.000 114.000 17.000 34.100 19.800 27.800 36.100 447.000 Sunshine Station No.of Fish 49.600 133.000 151.000 19.800 45.700 263.000 430.000 49.500 443.000 ...... I 95%Confidence 45.000 120.000 139.000 18.000 42.000 235.000 408.000 46.400 407.000 N OJ Interval 55.100 150.000 167.000 22.000 50.300 298.000 456.000 53.100 487.000 Talkeetna Station No.of Fish 10.900 4.800 3.100 3.300 5.100 20.800 49.100 2.300 73.000 95%Confidence 8.300 4.300 2.800 2.800 4.300 18.400 45.200 1.900 70.500 Interval 12.500 5.400 3.500 6.200 6.200 22.800 53.800 2.943 75.800 Curry Stat i on No.of Fish 11.300 2.800 1.300 1.100 2.400 13.100 29.400 1,000 59,000 95%Confidence 8,300 2.600 1,100 7,090 1,800 11 ,800 26,700 700 53,600 Interval 16.000 3.100 1,500 2.500 3,800 14,600 32.700 2.100 65,300 Source:Exhibit E.Table E.3.5. 1-29ResidentspeciesinthisreachincludealloftheresidentfishreportedintheSusitnaRiverdrainage(Table1.1-2)exceptforlaketrout.Residentspecies,otherthanburbotandlongnosesucker,primarilyusethismainstemareaasamigrationchanneltospawning,rearing,andsummerfeedingareasinthetributaries.Nomainstemspawningorrearingareashavebeenlocated.Rainbowtroutandgraylingoverwinterinmainstemhabitats.Burbotandlongnosesuckerusethemainstemasyear-roundhabitat.Burbotcatchesduringlowflowswererestrictedtothemainstemanddeepsidechannels.Duringhighflows,burbotwerecapturedatagreaternumberoflocations,includingshallowsidechannels.1.1.4.2.2SloughHabitatAdultsand/orjuvenilesoffivesalmonspecieshavebeenobservedinsloughhabitatbetweenDevilCanyonandTalkeetna.EstimatesofthetotalnumberofspawningsalmonbyspeciesandbyslougharegiveninTable1.1-6.Adultsockeyeandchumsalmonarethemostnumeroussalmoninthesesloughsduringpeakspawningperiods,whilecohoandchinookarerarelypresent.Twofactorscontributingtothesalmonspawninginthesloughsinthisreachareasfollows:(1)clear-waterbaseflowsoriginatingfromsourcessuchasgroundwaterupwelling,localsurfacerunoff,orinterstitialinflowensuremaintenanceflows;and(2)thepresenceofgroundwaterupwellinginthesloughsoxygenatesspawningsubstrate,keepssiltfromcompactingthespawninggravels,andprovidesastabletemperatureregimethatmaintainsincubatingembryosthroughthewinter.Sloughsserveasrearingandoverwinteringhabitatforjuvenilechinookandcohosalmon.Duringsummer,tributarysitesappeartobemoreimportantchinook-rearinghabitat,althoughclear-watersloughsalsoproviderearinghabitat.Cohojuvenilesappeartousesloughsandtributarymouthsitesforsummerrearing.Chum,pink,andsockeyefrywerepresentinsloughhabitatduringpartofthesummer.Theimportanceofsloughsasjuvenileoverwinteringandsummerrearinghabitatmayberelatedto(1)ice-free,clear-waterconditionsduringwintercomparedtoloweredflowandicingincohoandchinooknataltributaries;and(2)thehighstageofthemainsteminsummeractingasahydrauliccontrolatthesloughoutlet,increasingthedepthofwaterinthelowerendoftheslough,andpromptingbenthicproductioninclear-waterareas,whichimprovesthequalityoftherearinghabitatforjuvenilesalmon.AllresidentspeciesreportedinthisreachoftheSusitnadrainagehavebeenobservedinsloughhabitatbetweenDevilCanyonandTalkeetnaexceptforlaketrout.Availabledataindicatethatmostspeciesarepresentinsloughhabitatsaswellasthemainstemthroughwinter.Duringsummer,mostadultresidentsarenotabundantinsloughhabitat.Thosethatwererelativelyabundantinsloughhabitatduringsummerincludedburbot,longnosesucker,andrainbowtrout.Sloughsproviderearinghabitatduringlatesummermonthsforjuvenilewhitefish,grayling,andrainbowtrout.1.1.4.2.3TributaryHabitatInadditiontonumeroussmallerstreamsdrainingthesurroundinghillsides,thesixprincipaltributariestotheSusitnaRiverintheDevilCanyontoTalkeetnareacharePortageCreek,IndianRiver,GoldCreek,FourthofJulyCreek,LaneCreek,andWhiskersCreek.Tributariesinthisreachserveasprimaryspawninghabitatforchinook,coho,chum,andpinksalmon.ImportantspawningtributariesincludeIndianRiver(chinook,pink,chum,andcoho),PortageCreek(chinook,coho,pink,andchum),GashCreek(coho),LaneCreek(chinookandpinksalmon),andFourthofJulyCreek(chinook,pink,andchum).Tributariesinthisreachalsoserveasrearingandsummerfeedinghabitatforjuvenilechinookandcoho.Redistributionofjuvenilesfromareasofemergenceintributariestomorefavorablerearinghabitat,includingthemouthsoftributaries,occursthroughoutthesummerasfishbecomemoremobile.BetweenDevilCanyonandTalkeetna,tributariesandmouthsoftributariesprovidespawninghabitat,juvenile-rearingareas,andsummerfeedinghabitatforseveralresidentspeciesincludingrainbowtrout,arcticgrayling,roundwhitefish,andDollyVarden.Ingeneral,thesefishmigratefrommainstemorsloughhabitattotheclear-watertributariestospawninthespring(orearlyfallforDollyVarden).Oncespawningiscompleted,thefishmoveintofavorabletributaryhabitatforrearingandsummerfeeding.Asfreeze-upbegins,thefishmigratefromthetributariestothemainstemordeeperpoolsnearthemouthsoftributaries.Limitedinformationonwinterdistributionandabundanceindicatesthatfewresidentfishoverwinterinthetributaries.1.1.4.3TalkeetnatoCookInletThewaterresourcesandhabitatavailabilityoftheSusitnaRiverfromTalkeetnatoCookInletarecharacterizedinAppendixA,Sec.2.1.3.1-29ResidentspeciesinthisreachincludealloftheresidentfishreportedintheSusitnaRiverdrainage(Table1.1-2)exceptforlaketrout.Residentspecies,otherthanburbotandlongnosesucker,primarilyusethismainstemareaasamigrationchanneltospawning,rearing,andsummerfeedingareasinthetributaries.Nomainstemspawningorrearingareashavebeenlocated.Rainbowtroutandgraylingoverwinterinmainstemhabitats.Burbotandlongnosesuckerusethemainstemasyear-roundhabitat.Burbotcatchesduringlowflowswererestrictedtothemainstemanddeepsidechannels.Duringhighflows,burbotwerecapturedatagreaternumberoflocations,includingshallowsidechannels.1.1.4.2.2SloughHabitatAdultsand/orjuvenilesoffivesalmonspecieshavebeenobservedinsloughhabitatbetweenDevilCanyonandTalkeetna.EstimatesofthetotalnumberofspawningsalmonbyspeciesandbyslougharegiveninTable1.1-6.Adultsockeyeandchumsalmonarethemostnumeroussalmoninthesesloughsduringpeakspawningperiods,whilecohoandchinookarerarelypresent.Twofactorscontributingtothesalmonspawninginthesloughsinthisreachareasfollows:(1)clear-waterbaseflowsoriginatingfromsourcessuchasgroundwaterupwelling,localsurfacerunoff,orinterstitialinflowensuremaintenanceflows;and(2)thepresenceofgroundwaterupwellinginthesloughsoxygenatesspawningsubstrate,keepssiltfromcompactingthespawninggravels,andprovidesastabletemperatureregimethatmaintainsincubatingembryosthroughthewinter.Sloughsserveasrearingandoverwinteringhabitatforjuvenilechinookandcohosalmon.Duringsummer,tributarysitesappeartobemoreimportantchinook-rearinghabitat,althoughclear-watersloughsalsoproviderearinghabitat.Cohojuvenilesappeartousesloughsandtributarymouthsitesforsummerrearing.Chum,pink,andsockeyefrywerepresentinsloughhabitatduringpartofthesummer.Theimportanceofsloughsasjuvenileoverwinteringandsummerrearinghabitatmayberelatedto(1)ice-free,clear-waterconditionsduringwintercomparedtoloweredflowandicingincohoandchinooknataltributaries;and(2)thehighstageofthemainsteminsummeractingasahydrauliccontrolatthesloughoutlet,increasingthedepthofwaterinthelowerendoftheslough,andpromptingbenthicproductioninclear-waterareas,whichimprovesthequalityoftherearinghabitatforjuvenilesalmon.AllresidentspeciesreportedinthisreachoftheSusitnadrainagehavebeenobservedinsloughhabitatbetweenDevilCanyonandTalkeetnaexceptforlaketrout.Availabledataindicatethatmostspeciesarepresentinsloughhabitatsaswellasthemainstemthroughwinter.Duringsummer,mostadultresidentsarenotabundantinsloughhabitat.Thosethatwererelativelyabundantinsloughhabitatduringsummerincludedburbot,longnosesucker,andrainbowtrout.Sloughsproviderearinghabitatduringlatesummermonthsforjuvenilewhitefish,grayling,andrainbowtrout.1.1.4.2.3TributaryHabitatInadditiontonumeroussmallerstreamsdrainingthesurroundinghillsides,thesixprincipaltributariestotheSusitnaRiverintheDevilCanyontoTalkeetnareacharePortageCreek,IndianRiver,GoldCreek,FourthofJulyCreek,LaneCreek,andWhiskersCreek.Tributariesinthisreachserveasprimaryspawninghabitatforchinook,coho,chum,andpinksalmon.ImportantspawningtributariesincludeIndianRiver(chinook,pink,chum,andcoho),PortageCreek(chinook,coho,pink,andchum),GashCreek(coho),LaneCreek(chinookandpinksalmon),andFourthofJulyCreek(chinook,pink,andchum).Tributariesinthisreachalsoserveasrearingandsummerfeedinghabitatforjuvenilechinookandcoho.Redistributionofjuvenilesfromareasofemergenceintributariestomorefavorablerearinghabitat,includingthemouthsoftributaries,occursthroughoutthesummerasfishbecomemoremobile.BetweenDevilCanyonandTalkeetna,tributariesandmouthsoftributariesprovidespawninghabitat,juvenile-rearingareas,andsummerfeedinghabitatforseveralresidentspeciesincludingrainbowtrout,arcticgrayling,roundwhitefish,andDollyVarden.Ingeneral,thesefishmigratefrommainstemorsloughhabitattotheclear-watertributariestospawninthespring(orearlyfallforDollyVarden).Oncespawningiscompleted,thefishmoveintofavorabletributaryhabitatforrearingandsummerfeeding.Asfreeze-upbegins,thefishmigratefromthetributariestothemainstemordeeperpoolsnearthemouthsoftributaries.Limitedinformationonwinterdistributionandabundanceindicatesthatfewresidentfishoverwinterinthetributaries.1.1.4.3TalkeetnatoCookInletThewaterresourcesandhabitatavailabilityoftheSusitnaRiverfromTalkeetnatoCookInletarecharacterizedinAppendixA,Sec.2.1.3. 1-30Table1.1-6.Estimatednumberofslough-spawningsockeye,chum,andpinksalmoninsloughsbetweenOe?i1CanyonandTalkeetna,1981to19821RiverSockeyeChumPinkSloughMile198119821981198219811982199.60 0 6 0 002100.40 0300 0 03B101.42 000 0 03A101.99 000105107.20002t20 06A112.310112 035t28113.20 0480025080121.80 0 023t20 08C121.9020750 08B122.20 5 180"i-20 0Moose123.508167t26509A124.60 0140t20·00A124.70 0600 2 08A125.1191133620t2748028B126.309073032t29128.3146260t24200329B129.320311905 0 09A133.33 12071730010133.80 002 0 011135.317621131765732027613135.70 0 500015137.200 11013516137.3100 3 00017138.24909421t20 019139.72t20 31 0 120140.1641061630t2013321141.0004571222064t221A145.50 0102 00Estimatedtotal2315140235263674287351981estimatedtotal:5869slough-spawningsalmon.1982estimatedtotal:5811slough-spawningsalmon.tlTotalnumbersestimatedbycalculatingtheareaunderthecurveformedfromplottingnumberoflivesalmoninsloughsversusthedateanddividingbytheaverageestimatedstreamlife(asinBell1980)•Theestimatedstreamlifewas12dforsockeye,10dforchum,and7dforpinks.t2Insomecasesthepeak1ivec6untexceededthecalculatedtotalcount.Thepeaklivecountisused.Source:ExhibitE,TableE.3.12.1-30Table1.1-6.Estimatednumberofslough-spawningsockeye,chum,andpinksalmoninsloughsbetweenOe?i1CanyonandTalkeetna,1981to19821RiverSockeyeChumPinkSloughMile198119821981198219811982199.60 0 6 0 002100.40 0300 0 03B101.42 000 0 03A101.99 000105107.20002t20 06A112.310112 035t28113.20 0480025080121.80 0 023t20 08C121.9020750 08B122.20 5 180"i-20 0Moose123.508167t26509A124.60 0140t20·00A124.70 0600 2 08A125.1191133620t2748028B126.309073032t29128.3146260t24200329B129.320311905 0 09A133.33 12071730010133.80 002 0 011135.317621131765732027613135.70 0 500015137.200 11013516137.3100 3 00017138.24909421t20 019139.72t20 31 0 120140.1641061630t2013321141.0004571222064t221A145.50 0102 00Estimatedtotal2315140235263674287351981estimatedtotal:5869slough-spawningsalmon.1982estimatedtotal:5811slough-spawningsalmon.tlTotalnumbersestimatedbycalculatingtheareaunderthecurveformedfromplottingnumberoflivesalmoninsloughsversusthedateanddividingbytheaverageestimatedstreamlife(asinBell1980)•Theestimatedstreamlifewas12dforsockeye,10dforchum,and7dforpinks.t2Insomecasesthepeak1ivec6untexceededthecalculatedtotalcount.Thepeaklivecountisused.Source:ExhibitE,TableE.3.12. 1-311.1.4.3.1MainstemandSide-ChannelHabitatAdultsalmonpassthroughthisreachofthemainstemduringspawningmigration.Generally,themigrationperiodextendsfromlateMayintoSeptember.TherelativeabundanceofadultsalmoninthisreachishighbecausetheentireSusitnasalmonrunmustpassthroughthelowersectionsoftherivertoarriveatspawninggrounds.PopulationestimatesofthenumberofsalmonthatmigratetovariousescapementmonitoringstationsaregiveninTable1.1-5.Salmon-spawninghabitatinthemainstemorsidechannelsofthereachislimitedandiscomparabletothespawninghabitatdiscussedfortheDevilCanyontoTalkeetnareach.Ofthesixmainstemorside-channelspawningsitesidentifiedin1981,chumsalmonoccupiedsixandcohosalmonoccupiedone.Nomainstemorside-channelspawningwasobservedforchinookorsockeyesalmon.Mainstemandside-channelspawninghabitatisprobablyrestrictedbecauseofthelackofsuitablespawningsubstrateandupwelling,whicharetwoofthekeyfactorsdeterminingsubstratesuitabilityforspawning.Mainstemhabitatalsoprovidesoverwinteringforchinookandcohojuveniles,limitedsummerrearinghabitat,andamigratingchannelforsmo1toutmigration.Juvenilecohoarelessabundantthanjuvenilechinookandmoreoftenassociatedwithtributarymouthsites.BeringciscoandeulachonareanadromousspeciesthatusethemainstemasamigratorychannelfromCookInlettotheirrespectivespawningareas.BeringciscoareabundantinthemainstemfromAugusttoOctober.AlthoughspawningactivitymayoccurthroughoutthereachbetweenRM30andRM100,onlythreespawningconcentrationshavebeenidentified.Eu1achonwereobservedinthelower48mi(76.8km)ofthereachin1982andinthelower58mi(92.8km)in1981.AllresidentspeciesfoundintheSusitnadrainageexceptforlaketroutwerefoundinthisreachorthemainstem.LampreywereobservedinthisreachbutnotinotherreachesoftheSusitnaRiver.Arcticgrayling,rainbowtrout,DollyVarden,androundwhitefishareresidentfishthatusethemainstemasamigratorychanneltotributaryspawninghabitatandasoverwinteringhabitat.Burbotand10ngnosesuckerarepresentinthemainstemthroughouttheyearandutilizethemainstemforoverwintering,spawning,andjuvenilerearing.1.1.4.3.2SloughHabitatChum,sockeye,andpinksalmonadultsoccurinsloughs inthisreachoftheriver,althoughnoestimatesofrelativeabundancebyspeciesorsloughhavebeenmade.FactorsthatmaycontributetothesuitabilityofsloughsasspawninghabitatarethesameaspreviouslydiscussedfortheDevilCanyontoTalkeetnareach.Sloughhabitatalsoservesasimportantrearingandoverwinteringhabitatforjuvenilechinookandcohosalmon.Chinookjuvenilesarerelativelyabundantinsloughhabitatduringwinterandlessabundantinsummer.Juvenilecohoarelessabundantinsloughhabitatthanintributariesinthisreachthroughouttheyear.TheimportanceofsloughsasjuvenileoverwinteringandrearinghabitatmayberelatedtofactorsdiscussedpreviouslyfortheDevilCanyontoTalkeetnareach.ThesignificanceofsloughhabitatdownstreamfromTalkeetnatoresidentfishissimilartothatdiscussedforthereachbetweenDevilCanyonandTalkeetna.Sloughhabitatinthisreachisusedasoverwinteringhabitatforadultrainbowtrout,grayling,andwhitefish;year-roundhabitatforadultburbotandlongnosesucker;andrearinghabitatduringlatesummerforjuvenilewhitefish,grayling,andrainbowtrout.TheimportanceofsloughsasoverwinteringhabitatisrelatedtothesamefactorsasdiscussedpreviouslyforjuvenilesalmonspeciesintheDevilCanyontoTalkeetnareach.Nospawningsiteswereobservedinthesloughsofthisreach.Adultresidentsthataremostabundantinsloughhabitatduringsummerincludeburbot,10ngnose,sucker,andrainbowtrout.1.1.4.3.3TributaryHabitatAllofthesalmonspeciespresentintheSusitnadrainagehavebeenobservedintributariesdownstreamfromTalkeetna.Thehighestlevelofspawningforallsalmonspeciesinthisreachoccursinthetributaries.Basedonescapementcountsandpopulationestimatesatmonitoringstationsalongthemainstem,tributariesinthisreachprovidethemajorityofspawninghabitatintheSusitnadrainageforchinook,coho,andpinksalmon.Tributaryhabitatinthisreachalsosupportsrearingandsummerfeedinghabitatforjuvenilechinookandcohosalmon.Sitesassociatedwithtributarymouthsappeartoprovideparticularlyimportantrearingareas.Occurrenceofage0+cohoisparticularlyhighattributarymouthsitesduringsummer.Inaddition,tributarymouthsitesinthesereachesappeartoprovideoverwinteringhabitatforjuvenilecohosalmon.1-311.1.4.3.1MainstemandSide-ChannelHabitatAdultsalmonpassthroughthisreachofthemainstemduringspawningmigration.Generally,themigrationperiodextendsfromlateMayintoSeptember.TherelativeabundanceofadultsalmoninthisreachishighbecausetheentireSusitnasalmonrunmustpassthroughthelowersectionsoftherivertoarriveatspawninggrounds.PopulationestimatesofthenumberofsalmonthatmigratetovariousescapementmonitoringstationsaregiveninTable1.1-5.Salmon-spawninghabitatinthemainstemorsidechannelsofthereachislimitedandiscomparabletothespawninghabitatdiscussedfortheDevilCanyontoTalkeetnareach.Ofthesixmainstemorside-channelspawningsitesidentifiedin1981,chumsalmonoccupiedsixandcohosalmonoccupiedone.Nomainstemorside-channelspawningwasobservedforchinookorsockeyesalmon.Mainstemandside-channelspawninghabitatisprobablyrestrictedbecauseofthelackofsuitablespawningsubstrateandupwelling,whicharetwoofthekeyfactorsdeterminingsubstratesuitabilityforspawning.Mainstemhabitatalsoprovidesoverwinteringforchinookandcohojuveniles,limitedsummerrearinghabitat,andamigratingchannelforsmo1toutmigration.Juvenilecohoarelessabundantthanjuvenilechinookandmoreoftenassociatedwithtributarymouthsites.BeringciscoandeulachonareanadromousspeciesthatusethemainstemasamigratorychannelfromCookInlettotheirrespectivespawningareas.BeringciscoareabundantinthemainstemfromAugusttoOctober.AlthoughspawningactivitymayoccurthroughoutthereachbetweenRM30andRM100,onlythreespawningconcentrationshavebeenidentified.Eu1achonwereobservedinthelower48mi(76.8km)ofthereachin1982andinthelower58mi(92.8km)in1981.AllresidentspeciesfoundintheSusitnadrainageexceptforlaketroutwerefoundinthisreachorthemainstem.LampreywereobservedinthisreachbutnotinotherreachesoftheSusitnaRiver.Arcticgrayling,rainbowtrout,DollyVarden,androundwhitefishareresidentfishthatusethemainstemasamigratorychanneltotributaryspawninghabitatandasoverwinteringhabitat.Burbotand10ngnosesuckerarepresentinthemainstemthroughouttheyearandutilizethemainstemforoverwintering,spawning,andjuvenilerearing.1.1.4.3.2SloughHabitatChum,sockeye,andpinksalmonadultsoccurinsloughs inthisreachoftheriver,althoughnoestimatesofrelativeabundancebyspeciesorsloughhavebeenmade.FactorsthatmaycontributetothesuitabilityofsloughsasspawninghabitatarethesameaspreviouslydiscussedfortheDevilCanyontoTalkeetnareach.Sloughhabitatalsoservesasimportantrearingandoverwinteringhabitatforjuvenilechinookandcohosalmon.Chinookjuvenilesarerelativelyabundantinsloughhabitatduringwinterandlessabundantinsummer.Juvenilecohoarelessabundantinsloughhabitatthanintributariesinthisreachthroughouttheyear.TheimportanceofsloughsasjuvenileoverwinteringandrearinghabitatmayberelatedtofactorsdiscussedpreviouslyfortheDevilCanyontoTalkeetnareach.ThesignificanceofsloughhabitatdownstreamfromTalkeetnatoresidentfishissimilartothatdiscussedforthereachbetweenDevilCanyonandTalkeetna.Sloughhabitatinthisreachisusedasoverwinteringhabitatforadultrainbowtrout,grayling,andwhitefish;year-roundhabitatforadultburbotandlongnosesucker;andrearinghabitatduringlatesummerforjuvenilewhitefish,grayling,andrainbowtrout.TheimportanceofsloughsasoverwinteringhabitatisrelatedtothesamefactorsasdiscussedpreviouslyforjuvenilesalmonspeciesintheDevilCanyontoTalkeetnareach.Nospawningsiteswereobservedinthesloughsofthisreach.Adultresidentsthataremostabundantinsloughhabitatduringsummerincludeburbot,10ngnose,sucker,andrainbowtrout.1.1.4.3.3TributaryHabitatAllofthesalmonspeciespresentintheSusitnadrainagehavebeenobservedintributariesdownstreamfromTalkeetna.Thehighestlevelofspawningforallsalmonspeciesinthisreachoccursinthetributaries.Basedonescapementcountsandpopulationestimatesatmonitoringstationsalongthemainstem,tributariesinthisreachprovidethemajorityofspawninghabitatintheSusitnadrainageforchinook,coho,andpinksalmon.Tributaryhabitatinthisreachalsosupportsrearingandsummerfeedinghabitatforjuvenilechinookandcohosalmon.Sitesassociatedwithtributarymouthsappeartoprovideparticularlyimportantrearingareas.Occurrenceofage0+cohoisparticularlyhighattributarymouthsitesduringsummer.Inaddition,tributarymouthsitesinthesereachesappeartoprovideoverwinteringhabitatforjuvenilecohosalmon. 1-32Allresidentspeciesexceptforburbot,10ngnosesucker,andlaketroutweremostabundantinandatthemouthsofclear-watertributariesduringsummer.Informationonwinterdistributionandabundanceindicatesthatfewresidentfishoverwinterintributaryhabitat.Tributaryhabitatinthisreach,similartotheDevilCanyontoTalkeetnareach,apparentlyprovidesspawninghabitat,juvenile-rearingarea,andsummerfeedinghabitatforrainbowtrout,arcticgrayling,roundwhitefish,andDollyVarden.Ingeneral,thesefishmigrateduringspring(earlyfallforDollyVarden)fromthemainstemorsloughhabitattoclear-watertributariestospawn.Oncespawningiscompleted,fishmoveintofavorabletributaryhabitatforrearingandsummerfeeding.Asfreeze-upbegins,fishmigratefromtributariestothemainstemordeeperpoolsnearthemouthsoftributaries.1.1.4.4StreamsoftheAccessRoutesandTransmissionCorridorsTheportionoftheDenaliHighwaybetweenCantwellandtheWatanaAccessRoadcrosses10streamsintheJackRiverandNenanaRiverdrainages.FromtheDenaliHighwaytoWatana,theroadwillcrossLilyCreek,SeattleCreek,andBrushkanaCreek,aswellasnumerousunnamedstreams.Fishspeciespresentinthesestreamsincludegrayling,northernpike,burbot,whitefish,andsculpin.Ofthesespecies,thetributarystreamswouldcontainatleastgraylingandsculpin.TheupperreachesofDeadmanCreekwillbecrossedandparalleledbytheWatanaaccessroad.ThiscreekisatributaryoftheSusitnaRiverandisconsideredimportantgraylinghabitat.BetweentheWatanaandDevilCanyondamsites,theaccessroadwillcrossTsusenaCreekandcrossandparallelDevilCreek.Thestreamscontaingraylingandmaycontaincottids,whitefish,10ngnosesucker,andDollyVarden.TheroadwillcrosstheSusitnaRiverapproximately2mi(3km)belowtheDevilCanyondamsite.Salmonandprobablygrayling,whitefish,cottids,and10ngnosesuckeroccurinthevicinityofthecrossing.ThehabitatinthisreachoftheSusitnaisconsideredrelativelynonproductivecomparedtoreachesfartherdownstream.TherailroadbetweenDevilCanyonandGoldCreekwillcrossandparallelJackLongCreekandwillcrossGoldCreek.JackLongCreekcontainssmallnumbersofpink,coho,chinook,andchumsalmon.GoldCreekhasbeendocumentedtocontainchinook,afewcoho,andpinksalmon.ThreeunnamedtributariesoftheSusitnaRiverwillalsobecrossed.Thesestreamsmostlikelydonotcontainfishbecauseoftheirsteepgradients,buttheyareconsideredimportantsourcesofclearwatertosloughs19and20,whicharesalmonspawningareas.Withrespecttotransmissionlines,atleast27majorsalmonstreams,includingWillowCreek,KashwitnaRiver,TalkeetnaRiver,ChulitnaRiver,andIndianRiver,willbecrossedbytheintertieand,presumably,bytheadditionallinestobebuiltintheright-of-wayinconjunctionwiththeSusitnaHydroelectricProject.Thestreamscontaingrayling,rainbowtrout,DollyVarden,andcottidsinadditiontosalmon.SouthofWillow,thetransmissionlinewillberoutedbetweentheSusitnaRiverandtheParksHighwayformuchofitslength.ItwillcrossFishCreekandtheLittleSusitnaRiveraswellasmanyunnamedstreams.TheLittleSusitnaisaproductivefishriverandcontainscoho,pink,chinook,chum,andsockeyesalmon,aswellasrainbowtrout,DollyVarden,andgrayling.FishCreekisknowntosupportchinook,sockeye,pink,andcohosalmonandrainbowtrout.ManyoftheunnamedtributariestotheSusitnaRivermostlikelyprovidesalmonspawninghabitat.AnunderwatercrossingwillbeusedtocrosstheKnikArm.ThetransmissionlinewillthenproceedeastandsouthtotheUniversitypowersubstation.KnikArmservesasamigrationcorridorforfivespeciesofPacificsalmonaswellasotheranadromousspeciessuchasDollyVarden,Beringcisco,eu1achon,andlamprey.ThetransmissionlinewillskirtOtterLake,whichisstockedwithrainbowtrout,andwillcrossFossilandShipcreeks.FossilCreekisnotconsideredafishstream.ShipCreeksupportspopulationsof pink,chum,coho,sockeye,andchinooksalmonaswellasDollyVardenandrainbowtrout,butbecauseoftheheavydevelopmentalongitsreaches,itisnotconsideredprimefishhabitat.Plannedconstructionofadiversionwierforapowerplantintakewillblockupstreammovementsofanadromousfishpriortoconstructionofthetransmissionline.NorthofHealy,thetransmissionlinewillcrossatleast50creeksandriversincludingtheNenanaandTananarivers.ThesearetwoofAlaska'smajorriversandprovidehabitatforsalmon,grayling,whitefish,suckers,burbot,cottids,northernpike,andinconnu.PanguingeCreekhasbeendocumentedtocontaincohosalmon,DollyVarden,andgrayling.ThestreamsintheLittleGoldstreamvicinityarenotconsideredtobeimportantfisherieshabitatbecauseoftheirsteepgradients.Whilemanyofthestreamsgodryinthesummer,somedosupportgraylingpopulationsneartheirmouths.1-32Allresidentspeciesexceptforburbot,10ngnosesucker,andlaketroutweremostabundantinandatthemouthsofclear-watertributariesduringsummer.Informationonwinterdistributionandabundanceindicatesthatfewresidentfishoverwinterintributaryhabitat.Tributaryhabitatinthisreach,similartotheDevilCanyontoTalkeetnareach,apparentlyprovidesspawninghabitat,juvenile-rearingarea,andsummerfeedinghabitatforrainbowtrout,arcticgrayling,roundwhitefish,andDollyVarden.Ingeneral,thesefishmigrateduringspring(earlyfallforDollyVarden)fromthemainstemorsloughhabitattoclear-watertributariestospawn.Oncespawningiscompleted,fishmoveintofavorabletributaryhabitatforrearingandsummerfeeding.Asfreeze-upbegins,fishmigratefromtributariestothemainstemordeeperpoolsnearthemouthsoftributaries.1.1.4.4StreamsoftheAccessRoutesandTransmissionCorridorsTheportionoftheDenaliHighwaybetweenCantwellandtheWatanaAccessRoadcrosses10streamsintheJackRiverandNenanaRiverdrainages.FromtheDenaliHighwaytoWatana,theroadwillcrossLilyCreek,SeattleCreek,andBrushkanaCreek,aswellasnumerousunnamedstreams.Fishspeciespresentinthesestreamsincludegrayling,northernpike,burbot,whitefish,andsculpin.Ofthesespecies,thetributarystreamswouldcontainatleastgraylingandsculpin.TheupperreachesofDeadmanCreekwillbecrossedandparalleledbytheWatanaaccessroad.ThiscreekisatributaryoftheSusitnaRiverandisconsideredimportantgraylinghabitat.BetweentheWatanaandDevilCanyondamsites,theaccessroadwillcrossTsusenaCreekandcrossandparallelDevilCreek.Thestreamscontaingraylingandmaycontaincottids,whitefish,10ngnosesucker,andDollyVarden.TheroadwillcrosstheSusitnaRiverapproximately2mi(3km)belowtheDevilCanyondamsite.Salmonandprobablygrayling,whitefish,cottids,and10ngnosesuckeroccurinthevicinityofthecrossing.ThehabitatinthisreachoftheSusitnaisconsideredrelativelynonproductivecomparedtoreachesfartherdownstream.TherailroadbetweenDevilCanyonandGoldCreekwillcrossandparallelJackLongCreekandwillcrossGoldCreek.JackLongCreekcontainssmallnumbersofpink,coho,chinook,andchumsalmon.GoldCreekhasbeendocumentedtocontainchinook,afewcoho,andpinksalmon.ThreeunnamedtributariesoftheSusitnaRiverwillalsobecrossed.Thesestreamsmostlikelydonotcontainfishbecauseoftheirsteepgradients,buttheyareconsideredimportantsourcesofclearwatertosloughs19and20,whicharesalmonspawningareas.Withrespecttotransmissionlines,atleast27majorsalmonstreams,includingWillowCreek,KashwitnaRiver,TalkeetnaRiver,ChulitnaRiver,andIndianRiver,willbecrossedbytheintertieand,presumably,bytheadditionallinestobebuiltintheright-of-wayinconjunctionwiththeSusitnaHydroelectricProject.Thestreamscontaingrayling,rainbowtrout,DollyVarden,andcottidsinadditiontosalmon.SouthofWillow,thetransmissionlinewillberoutedbetweentheSusitnaRiverandtheParksHighwayformuchofitslength.ItwillcrossFishCreekandtheLittleSusitnaRiveraswellasmanyunnamedstreams.TheLittleSusitnaisaproductivefishriverandcontainscoho,pink,chinook,chum,andsockeyesalmon,aswellasrainbowtrout,DollyVarden,andgrayling.FishCreekisknowntosupportchinook,sockeye,pink,andcohosalmonandrainbowtrout.ManyoftheunnamedtributariestotheSusitnaRivermostlikelyprovidesalmonspawninghabitat.AnunderwatercrossingwillbeusedtocrosstheKnikArm.ThetransmissionlinewillthenproceedeastandsouthtotheUniversitypowersubstation.KnikArmservesasamigrationcorridorforfivespeciesofPacificsalmonaswellasotheranadromousspeciessuchasDollyVarden,Beringcisco,eu1achon,andlamprey.ThetransmissionlinewillskirtOtterLake,whichisstockedwithrainbowtrout,andwillcrossFossilandShipcreeks.FossilCreekisnotconsideredafishstream.ShipCreeksupportspopulationsof pink,chum,coho,sockeye,andchinooksalmonaswellasDollyVardenandrainbowtrout,butbecauseoftheheavydevelopmentalongitsreaches,itisnotconsideredprimefishhabitat.Plannedconstructionofadiversionwierforapowerplantintakewillblockupstreammovementsofanadromousfishpriortoconstructionofthetransmissionline.NorthofHealy,thetransmissionlinewillcrossatleast50creeksandriversincludingtheNenanaandTananarivers.ThesearetwoofAlaska'smajorriversandprovidehabitatforsalmon,grayling,whitefish,suckers,burbot,cottids,northernpike,andinconnu.PanguingeCreekhasbeendocumentedtocontaincohosalmon,DollyVarden,andgrayling.ThestreamsintheLittleGoldstreamvicinityarenotconsideredtobeimportantfisherieshabitatbecauseoftheirsteepgradients.Whilemanyofthestreamsgodryinthesummer,somedosupportgraylingpopulationsneartheirmouths. 1-331.1.5Fisheries1.1.5.1CommercialFigure1.1-4showstheADF&GupperCookInletsalmonharveststatisticalareas.TheupperCookInletcommercialfisheryharvestsmixedstocks(Table1.1-7).Withtheexceptionofsockeyesalmon,themajorityofupperCookInletsalmonproductionoriginatesintheSusitnadrainage.TheSusitnaRiverisconsideredthemostimportantsalmon-producingsysteminupperCookInlet;however,thequantitativecontributionoftheSusitnaRivertothecommercialfisherycanonlybeapproximatedbecauseof(1)thehighnumberofintradrainagespawningandrearingareas;(2)thelackofdataonotherknownandsuspectedsalmon-producingsystemsinupperCookInlet;(3)thelackofstocksepara~ionprograms(exceptforsockeyesalmon)(ADF&G1982b);and(4)overlapinmigrationtimingofmixedstocksandspeciesinCookInletharvestareas.ThesalmonstocksspawningintheSusitnaRiverdrainagealsocontributetothecommercialfisheryinlowerCookInlet,althoughdataarenotavailabletoestimatepercentcontributions.FurtherdiscussionofthesocioeconomicaspectsofthecommercialsalmonharvestiscontainedinAppendixN.1.1.5.1.1ChinookSince1954,thecommercialcatchofchinooksalmoninupperCookInlethasaveraged19,500fish(Table1.1-5).Since1964,theopeningdateofthecommercialfisheryhasbeenJune25,andtheSusitnaRiverchinooksalmonrunbeginsinlateMayandpeaksinmid-June.Thus,themajorityofchinookhavealreadypassedthroughtheareasubjecttocommercialfishing.EstimatesofchinooksalmonescapementinthereachaboveTalkeetnawere10,900fishin1982(Table1.1-5).Thisrepresented22.0%ofthechinookescapementpastSunshineStation(Figure1.1-4).1.1.5.1.2ChumTheupperCookInletchumsalmoncatchhasaveragedapproximately614,000fishannuallysince1954(Table1.1-7).The1981and1982estimatesofchumsalmonescapementinthereachaboveTalkeetnawere20,800and49,100fish(Table1.1-5).Theserepresented7.9and11.4%,respectively,oftheestimatedchumescapementpastSunshineStation(Figure1.1-4).1.1.5.1.3CohoSalmonSince1954,theupperCookInletcohosalmoncommercialcatchhasaveragedapproximately230,000fish(Table1.1-7).The1981and1982estimatesofcohosalmonescapementinthereachaboveTalkeetnawere3300and5100fish(Table1.1-5).Theserepresented16.7and11.1%,respectively,oftheestimatedcohoescapementpastSunshineStation(Figure1.1-4).1.1.5.1.4PinkSalmonTheupperCookInletaverageodd-yearharvestofpinksalmonsince1954isabout124,000fish,witharangeof12,500to554,000,whiletheaverageeven-yearharvestisapproximately1,701,000fish,witharangeof484,000to3,232,000(Table1.1-7).TheestimatesofpinksalmonescapementinthereachaboveTalkeetnawereabout2300fishin1981and73,000in1982(Table1.1-5).Theserepresented4.6and16.5%,respectively,ofthepinkescapementpastSunshineStation(Figure1.1-4).1.1.5.1.5SockeyeThecommercialsockeyeharvesthasaveragedapproximately1,114,000fishannuallyinupperCookInletoverthelast28years(Table1.1-7).TheestimatedsockeyeescapementinthereachaboveTalkeetnawas4800fishin1981and3100in1982(TableB-5).Theserepresented3.6and2.0%,respectively,oftheestimatedsockeyeescapementpastSunshineStation(Figure1.1-4).1.1.5.1.6StockSeparationTheapplicanthaspreparedareportfocusingonthefeasibilityofassessingtheSusitnaRivercontributiontothecommercialsalmonfisheryinupperCookInletthroughastockidentificationprogram(ADF&G1982b).ThereportincludesanexaminationofsalmonharvestdatafortheCookInletcommercialfisheryandareviewofliteratureonupperCookInletfisheryprogramsandstockidentificationtechniques.Thetworecommendationsinthereportare:1."Developaninventorysystemtodeterminecharacteristics(timing,length,weight,age)ofsalmonrunstowestsidesystemsofupperCookInlet.Shouldthewest-sidesystemsnotbeconsidered,theactualcontributionbytheSusitnaRiverdrainagewillbemisrepresented.1-331.1.5Fisheries1.1.5.1CommercialFigure1.1-4showstheADF&GupperCookInletsalmonharveststatisticalareas.TheupperCookInletcommercialfisheryharvestsmixedstocks(Table1.1-7).Withtheexceptionofsockeyesalmon,themajorityofupperCookInletsalmonproductionoriginatesintheSusitnadrainage.TheSusitnaRiverisconsideredthemostimportantsalmon-producingsysteminupperCookInlet;however,thequantitativecontributionoftheSusitnaRivertothecommercialfisherycanonlybeapproximatedbecauseof(1)thehighnumberofintradrainagespawningandrearingareas;(2)thelackofdataonotherknownandsuspectedsalmon-producingsystemsinupperCookInlet;(3)thelackofstocksepara~ionprograms(exceptforsockeyesalmon)(ADF&G1982b);and(4)overlapinmigrationtimingofmixedstocksandspeciesinCookInletharvestareas.ThesalmonstocksspawningintheSusitnaRiverdrainagealsocontributetothecommercialfisheryinlowerCookInlet,althoughdataarenotavailabletoestimatepercentcontributions.FurtherdiscussionofthesocioeconomicaspectsofthecommercialsalmonharvestiscontainedinAppendixN.1.1.5.1.1ChinookSince1954,thecommercialcatchofchinooksalmoninupperCookInlethasaveraged19,500fish(Table1.1-5).Since1964,theopeningdateofthecommercialfisheryhasbeenJune25,andtheSusitnaRiverchinooksalmonrunbeginsinlateMayandpeaksinmid-June.Thus,themajorityofchinookhavealreadypassedthroughtheareasubjecttocommercialfishing.EstimatesofchinooksalmonescapementinthereachaboveTalkeetnawere10,900fishin1982(Table1.1-5).Thisrepresented22.0%ofthechinookescapementpastSunshineStation(Figure1.1-4).1.1.5.1.2ChumTheupperCookInletchumsalmoncatchhasaveragedapproximately614,000fishannuallysince1954(Table1.1-7).The1981and1982estimatesofchumsalmonescapementinthereachaboveTalkeetnawere20,800and49,100fish(Table1.1-5).Theserepresented7.9and11.4%,respectively,oftheestimatedchumescapementpastSunshineStation(Figure1.1-4).1.1.5.1.3CohoSalmonSince1954,theupperCookInletcohosalmoncommercialcatchhasaveragedapproximately230,000fish(Table1.1-7).The1981and1982estimatesofcohosalmonescapementinthereachaboveTalkeetnawere3300and5100fish(Table1.1-5).Theserepresented16.7and11.1%,respectively,oftheestimatedcohoescapementpastSunshineStation(Figure1.1-4).1.1.5.1.4PinkSalmonTheupperCookInletaverageodd-yearharvestofpinksalmonsince1954isabout124,000fish,witharangeof12,500to554,000,whiletheaverageeven-yearharvestisapproximately1,701,000fish,witharangeof484,000to3,232,000(Table1.1-7).TheestimatesofpinksalmonescapementinthereachaboveTalkeetnawereabout2300fishin1981and73,000in1982(Table1.1-5).Theserepresented4.6and16.5%,respectively,ofthepinkescapementpastSunshineStation(Figure1.1-4).1.1.5.1.5SockeyeThecommercialsockeyeharvesthasaveragedapproximately1,114,000fishannuallyinupperCookInletoverthelast28years(Table1.1-7).TheestimatedsockeyeescapementinthereachaboveTalkeetnawas4800fishin1981and3100in1982(TableB-5).Theserepresented3.6and2.0%,respectively,oftheestimatedsockeyeescapementpastSunshineStation(Figure1.1-4).1.1.5.1.6StockSeparationTheapplicanthaspreparedareportfocusingonthefeasibilityofassessingtheSusitnaRivercontributiontothecommercialsalmonfisheryinupperCookInletthroughastockidentificationprogram(ADF&G1982b).ThereportincludesanexaminationofsalmonharvestdatafortheCookInletcommercialfisheryandareviewofliteratureonupperCookInletfisheryprogramsandstockidentificationtechniques.Thetworecommendationsinthereportare:1."Developaninventorysystemtodeterminecharacteristics(timing,length,weight,age)ofsalmonrunstowestsidesystemsofupperCookInlet.Shouldthewest-sidesystemsnotbeconsidered,theactualcontributionbytheSusitnaRiverdrainagewillbemisrepresented. 1-34Table1.1-7.CommercialCatchofUpperCookInletSalmoninNumbersofFishbySpecies,1954-1982tlYearChinookSockeyeCohoPinkChumTotal195463,7801,207,046321,5252,189,307510,0684,291,726195545,9261,027,528170,777101,680248,3431,594,254195664,9771,258,789198,1891,595,375782,0513,899,381195742,158643,712125,43421,2281,001,4701,834,002195822,727477,392239,7651,648,548471,6972,860,129195932,651612,676106,31212,527300,3191,064,485196027,512923,314311,4611,411,605659,9973,333,889196119,2101,162,303117,77834,017349,6281,683,463196220,2101,147,573350,3242,711,689970,5825,200,378196317,536942,980197,14030,436387,0271,575,11919644,531970,055452,6543,231,9611,079,0845,738,28519659,7411,412,350153,61923,963 316,4441,916,11719669,5411,851,990289,6902,006,580531,8254,689,62619677,8591,380,062177,72932,229296,0371,894,71619684,5361,104,904470,4502,278,1971,119,1144,977,201196912,398692,254100,95233,422269,8551,108,88119708,348731,214275,296813,895775,1672,603,920197119,765636,303100,63635,624327,0291,119,357197216,086879,82480,933628,580630,1482,235,57119735,194670,025104,420326,184667,5731,773,39619746,596497,185200,125483,730396,8401,584,47619754,780684,818227,372336,359951,7962,205,135197610,8671,664,150208,7101,256,744469,8073,610,278197714,7922,054,020192,975544,1841,233,7331,049,704197817,3032,622,487219,2341,687,092571,9255,118,041197913,738924,415265,16672,982650,3571,926,658198012,4971,584,392283,6231,871,058387,0784,138,648198111,5481,443,294494,073127,857842,8492,919,621Average19,5481,114,408229,684even-1,701,026614,3842,891,894odd-124,4591982t220,6363,237,376777,132788,9721,428,6216,252,737tlDataaregraphedinFigure3.1.4-3.t2ADF&Gpreliminarydata.Source:ExhibitE,TableE.3.3.1-34Table1.1-7.CommercialCatchofUpperCookInletSalmoninNumbersofFishbySpecies,1954-1982tlYearChinookSockeyeCohoPinkChumTotal195463,7801,207,046321,5252,189,307510,0684,291,726195545,9261,027,528170,777101,680248,3431,594,254195664,9771,258,789198,1891,595,375782,0513,899,381195742,158643,712125,43421,2281,001,4701,834,002195822,727477,392239,7651,648,548471,6972,860,129195932,651612,676106,31212,527300,3191,064,485196027,512923,314311,4611,411,605659,9973,333,889196119,2101,162,303117,77834,017349,6281,683,463196220,2101,147,573350,3242,711,689970,5825,200,378196317,536942,980197,14030,436387,0271,575,11919644,531970,055452,6543,231,9611,079,0845,738,28519659,7411,412,350153,61923,963 316,4441,916,11719669,5411,851,990289,6902,006,580531,8254,689,62619677,8591,380,062177,72932,229296,0371,894,71619684,5361,104,904470,4502,278,1971,119,1144,977,201196912,398692,254100,95233,422269,8551,108,88119708,348731,214275,296813,895775,1672,603,920197119,765636,303100,63635,624327,0291,119,357197216,086879,82480,933628,580630,1482,235,57119735,194670,025104,420326,184667,5731,773,39619746,596497,185200,125483,730396,8401,584,47619754,780684,818227,372336,359951,7962,205,135197610,8671,664,150208,7101,256,744469,8073,610,278197714,7922,054,020192,975544,1841,233,7331,049,704197817,3032,622,487219,2341,687,092571,9255,118,041197913,738924,415265,16672,982650,3571,926,658198012,4971,584,392283,6231,871,058387,0784,138,648198111,5481,443,294494,073127,857842,8492,919,621Average19,5481,114,408229,684even-1,701,026614,3842,891,894odd-124,4591982t220,6363,237,376777,132788,9721,428,6216,252,737tlDataaregraphedinFigure3.1.4-3.t2ADF&Gpreliminarydata.Source:ExhibitE,TableE.3.3. 1-352."Escapementsamplingforage-weight-lengthinformationcurrentlyimplementedinmajorsockeyesalmonproducingsystemsshouldbeexpandedtoincludechumandcohosalmon.Length-weightdataandtissuesamplesforelectrophoresisshouldalsobecollectedfrompinksalmon.Thesedatacombinedwithruntimingandinformationregardingwest-sidesystemswillprovidethebasisfordeterminingifstockspecificcharacteristicsarepresentforeachspeciesbywhichastockseparationprogrammaybedeveloped".BasedonresearchbyBilton(1971),Grantetal.(1980),McGregor(1983),andOkazaki(1981),itisthejudgmentoftheFERCstaffthatastockidentificationprogramdesignedtoassesstheSusitnaRivercontributiontothecommerc;alsalmonfisheryinupperCookInletisnotlikelytobeverysuccessfulforanyofthefivespecies.Wepredictthatoverlapinthefrequencydistributionsforthepossiblemorphometric,meristic,andbiochemicalcharacterswillbesogreatthat,inasampleofsalmonfrommixedstocksinCookInlet,theabilitytocorrectlyclassifySusitnaRiversalmonwillbesolowastobeoflimitedvalue.1.1.5.2SportRecentincreasesinpopulationandtourisminAlaskahaveresultedinagrowingdemandforrecreationalfishing.Recreationalfishingisnowconsideredasignificantfactorintotalfisheriesmanagement,especiallyinCookInletwherecommercialandnoncommercialuserconflictshavedeveloped(Mills1980).TheSusitnaRiveranditsmajorsalmonandresidentfish-producingtributariesprovideamultispeciessportfisheryeasilyaccessiblefromAnchorageandotherCookInletcommunities.In1978,theSusitnaRiveranditsprimarytributariesaccountedforover124,000anglerdaysofsportfishingeffort,about10%ofthetotalanglerdaysinAlaska(Mills1980).In1981over102,240anglerdayswereexpendedintheSusitnaBasin,representingabout7%ofthetotalanglerdaysinAlaska(Mills1982).Thesportfishharvestsfor1978through1981fromtheSusitnabasin,basedonmailingsurveystoasampleoflicenses,areshowninTable1.1-8(Mills1979, 1980, 1981,1982).ThefiguresrepresentthesportfishingharvestthroughouttheSusitnabasinandinclUdeanareathatislargerthanthatwhichwouldbeaffectedbytheproposedproject(seeFigures1.1-11to1.1-13forlocationsofmajortributarieslistedinTable1.1-8).The1978and1981estimatedsportcatchesofarcticgraylingrepresentabout28and33%,respectively,oftheestimatedgraylingharvestinsouth-centralAlaska.Theestimatedsportcatchofrainbowtroutrepresentsabout13and10%oftheentirestateharvestin1978and1981,respectively.The1978and1981Susitnasportharvestofpinksalmonrepresentsabout39and13%ofthetotalestimatedsportharvestforsouth-centralAlaska;theharvestofcohorepresentsabout18and10%;andtheharvestofchinookrepresentsabout11and19%.1.1.5.3SubsistenceAlthoughsalmonformanimportantresourceformanySusitnabasinresidents,subsistencefishingwithintheSusitnabasiniscurrentlyanunquantifiedharvest.TheDivisionofSubsistenceoftheAlaskaDepartmentofFishandGameservesasaresearchgroupwithresponsibilitytogatherdataonresourceuses;toprovidethesedatatotheBoards.wildlifeagencies,andthepublic;andtoadvisedecision-makingbodiesontheadoptionofregulationsandplansthataffectsubsistenceuses.TheDivisiondoesnotmanagesubsistencefisheries,doesnotissuepermits,andhasnoenforcementauthority.However,theDivisioniscollectinginformationintheSusitnaRiverbasinthatwillpermitbetterquantificationandunderstandingofpresentlevelsofsubsistencefishing.TheDivision'sreport(Foster1982)onuseofchinooksalmonbyresidentsofTyonekonthewestsideofUpperCookInletisagoodexampleofthetypeofstudythatisneededforanumberofothersites,andnotjustsitesinvolvingsubsistencefishingbynatives.Foster'sresultsdemonstratetheimportantrolethattheutilizationofchinookplaysintheongoinglifeofthevillage.Numbersofchinookharvestedrangedbetween1500and2000fortheyears1980-1982;10to15%asmanysockeyewerealsoharvested.1.1.5.4SalmonEnhancementPlanTheCookInletAquacultureAssociationandtheAlaskaDepartmentofFishandGame(1981)havedevelopedaCookInletRegionalSalmonEnhancementPlan.1981-2000.Theunderlyingprinciplesforthisplanareasfollows:Enhancementofthesalmonresourceinanysignificantandlastingfashionwilldependonacarefulbalanceofmanagementforthewildstocksandtheorderlyintroductionofsupplementalproduction.1-352."Escapementsamplingforage-weight-lengthinformationcurrentlyimplementedinmajorsockeyesalmonproducingsystemsshouldbeexpandedtoincludechumandcohosalmon.Length-weightdataandtissuesamplesforelectrophoresisshouldalsobecollectedfrompinksalmon.Thesedatacombinedwithruntimingandinformationregardingwest-sidesystemswillprovidethebasisfordeterminingifstockspecificcharacteristicsarepresentforeachspeciesbywhichastockseparationprogrammaybedeveloped".BasedonresearchbyBilton(1971),Grantetal.(1980),McGregor(1983),andOkazaki(1981),itisthejudgmentoftheFERCstaffthatastockidentificationprogramdesignedtoassesstheSusitnaRivercontributiontothecommerc;alsalmonfisheryinupperCookInletisnotlikelytobeverysuccessfulforanyofthefivespecies.Wepredictthatoverlapinthefrequencydistributionsforthepossiblemorphometric,meristic,andbiochemicalcharacterswillbesogreatthat,inasampleofsalmonfrommixedstocksinCookInlet,theabilitytocorrectlyclassifySusitnaRiversalmonwillbesolowastobeoflimitedvalue.1.1.5.2SportRecentincreasesinpopulationandtourisminAlaskahaveresultedinagrowingdemandforrecreationalfishing.Recreationalfishingisnowconsideredasignificantfactorintotalfisheriesmanagement,especiallyinCookInletwherecommercialandnoncommercialuserconflictshavedeveloped(Mills1980).TheSusitnaRiveranditsmajorsalmonandresidentfish-producingtributariesprovideamultispeciessportfisheryeasilyaccessiblefromAnchorageandotherCookInletcommunities.In1978,theSusitnaRiveranditsprimarytributariesaccountedforover124,000anglerdaysofsportfishingeffort,about10%ofthetotalanglerdaysinAlaska(Mills1980).In1981over102,240anglerdayswereexpendedintheSusitnaBasin,representingabout7%ofthetotalanglerdaysinAlaska(Mills1982).Thesportfishharvestsfor1978through1981fromtheSusitnabasin,basedonmailingsurveystoasampleoflicenses,areshowninTable1.1-8(Mills1979, 1980, 1981,1982).ThefiguresrepresentthesportfishingharvestthroughouttheSusitnabasinandinclUdeanareathatislargerthanthatwhichwouldbeaffectedbytheproposedproject(seeFigures1.1-11to1.1-13forlocationsofmajortributarieslistedinTable1.1-8).The1978and1981estimatedsportcatchesofarcticgraylingrepresentabout28and33%,respectively,oftheestimatedgraylingharvestinsouth-centralAlaska.Theestimatedsportcatchofrainbowtroutrepresentsabout13and10%oftheentirestateharvestin1978and1981,respectively.The1978and1981Susitnasportharvestofpinksalmonrepresentsabout39and13%ofthetotalestimatedsportharvestforsouth-centralAlaska;theharvestofcohorepresentsabout18and10%;andtheharvestofchinookrepresentsabout11and19%.1.1.5.3SubsistenceAlthoughsalmonformanimportantresourceformanySusitnabasinresidents,subsistencefishingwithintheSusitnabasiniscurrentlyanunquantifiedharvest.TheDivisionofSubsistenceoftheAlaskaDepartmentofFishandGameservesasaresearchgroupwithresponsibilitytogatherdataonresourceuses;toprovidethesedatatotheBoards.wildlifeagencies,andthepublic;andtoadvisedecision-makingbodiesontheadoptionofregulationsandplansthataffectsubsistenceuses.TheDivisiondoesnotmanagesubsistencefisheries,doesnotissuepermits,andhasnoenforcementauthority.However,theDivisioniscollectinginformationintheSusitnaRiverbasinthatwillpermitbetterquantificationandunderstandingofpresentlevelsofsubsistencefishing.TheDivision'sreport(Foster1982)onuseofchinooksalmonbyresidentsofTyonekonthewestsideofUpperCookInletisagoodexampleofthetypeofstudythatisneededforanumberofothersites,andnotjustsitesinvolvingsubsistencefishingbynatives.Foster'sresultsdemonstratetheimportantrolethattheutilizationofchinookplaysintheongoinglifeofthevillage.Numbersofchinookharvestedrangedbetween1500and2000fortheyears1980-1982;10to15%asmanysockeyewerealsoharvested.1.1.5.4SalmonEnhancementPlanTheCookInletAquacultureAssociationandtheAlaskaDepartmentofFishandGame(1981)havedevelopedaCookInletRegionalSalmonEnhancementPlan.1981-2000.Theunderlyingprinciplesforthisplanareasfollows:Enhancementofthesalmonresourceinanysignificantandlastingfashionwilldependonacarefulbalanceofmanagementforthewildstocksandtheorderlyintroductionofsupplementalproduction. COOKINLET1-36SUSITNARIVERANDMAJORTRIBUTARIESFROMMOUTHTOLITTLEWILLOWCREEK,-'ANCHOR~GE--_..:'"...._"-_..JO,..~~5=i_;;1?'Mileso510 15KilometersFigure1.1-11.SusitnaRiverandMajorTributariesfromMouthtoLittleWillowCreek.Source:ExhibitE.FigureE.3.4.COOKINLET1-36SUSITNARIVERANDMAJORTRIBUTARIESFROMMOUTHTOLITTLEWILLOWCREEK,-'ANCHOR~GE--_..:'"...._"-_..JO,..~~5=i_;;1?'Mileso510 15KilometersFigure1.1-11.SusitnaRiverandMajorTributariesfromMouthtoLittleWillowCreek.Source:ExhibitE.FigureE.3.4. 1-37o••~~~;;~,oMiles~Io51015KilomelersSUSITNARIVERANDMAJORTRIBUTARIESFROMMONTANACREEKTODEVILCANYONFigure1.1-12.SusitnaRiverandMajorTributariesfromMontanaCreektoDevilCanyon.Source:ExhibitE,FigureE.3.5.1-37o••~~~;;~,oMiles~Io51015KilomelersSUSITNARIVERANDMAJORTRIBUTARIESFROMMONTANACREEKTODEVILCANYONFigure1.1-12.SusitnaRiverandMajorTributariesfromMontanaCreektoDevilCanyon.Source:ExhibitE,FigureE.3.5. 0,••,..5 10 Miles II ::-=-;;;( o 5 - - -·10 15 Kllol1lelers o ../' ..r--.J ,,,0. Q;Q; ~f....(j River Cl.t: c?~ SUSITNA RIVER AND MAJOR TRIBUTARIES FROM DEVIL CANYON TO DENALI HIGHWAY t-I I W <Xl Figure 1.1-13.Susitna River and Major Tributaries from Devil Canyon to Denali Highway. Source:Exhibit E,Figure E.3.6. River o 5 10 Miles =-~o 5 ----10 1 5 Kllol1lelers SUSITNA RIVER AND MAJOR TRIBUTARIES FROM DEVIL CANYON TO DENALI HIGHWAY Figure 1.1-13.Susitna River and Major Tributaries from Devil Canyon to Denali Highway. Source:Exhibit E,Figure E.3.6. t-I I W <Xl Table 1.1-8.Susitna Basin Sport Fish Harvest and Effort by Fishery and Species -1978,1979,1980 and 1981 1978 tl Days Locations Fished KS SS RS PS CS RT DV LT GR BB Wi 11 ow Creek 22,682 47 905 56 18,901 2,458 913 280 0 208 9 Caswell Creek Montana Creek 25,762 408 2,451 85 15,619 4,429 1,193 633 0 958 9 Sunshine Creek Clear (Chunilna) Creek 5,040 12 2,200 28 2,074 1,912 1,501 1,817 0 859 27 Sheep Creek 11,869 256 478 14 6,981 1,697 470 108 0 461 18 Little Willow ..... Creek 5,687 0 151 28 3,142 1,015 334 63 0 334 0 I W Deshka River 9,111 850t2 1,798 0 697 0 3,634 0 0 579 0 1.0 Lake Creek 8,767 326t2 2,212 254 2,833 1,015 2,721 154 36 2,115 45 Alexander Creek 6,914 769t2 2,401 183 1,146 215 2,640 136 0 1,871 0 Talachulitna River 732 12t2 88 141 31 234 0 235 0 99 0 Lake Louise, Lake Susitna, Tyone River 13,161 0 0 0 0 0 0 0 2,522 2,278 2,947 Others 14,970 163 2,388 56 3,994 2,692 1,519 2,739 877 3,770 208 1978 total 124,695 2,843 15,072 845 55,418 15,667 14,925 6,165 3,435 13,532 3,263 tlKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8.Susitna Basin Sport Fish Harvest and Effort by Fishery and Species -1978,1979,1980 and 1981 1978 tl Days Locations Fished KS SS RS PS CS RT DV LT GR BB Wi 11 ow Creek 22,682 47 905 56 18,901 2,458 913 280 0 208 9 Caswell Creek Montana Creek 25,762 408 2,451 85 15,619 4,429 1,193 633 0 958 9 Sunshine Creek Clear (Chunilna) Creek 5,040 12 2,200 28 2,074 1,912 1,501 1,817 0 859 27 Sheep Creek 11,869 256 478 14 6,981 1,697 470 108 0 461 18 Little Willow ..... Creek 5,687 0 151 28 3,142 1,015 334 63 0 334 0 I W Deshka River 9,111 850t2 1,798 0 697 0 3,634 0 0 579 0 1.0 Lake Creek 8,767 326t2 2,212 254 2,833 1,015 2,721 154 36 2,115 45 Alexander Creek 6,914 769t2 2,401 183 1,146 215 2,640 136 0 1,871 0 Talachulitna River 732 12t2 88 141 31 234 0 235 0 99 0 Lake Louise, Lake Susitna, Tyone River 13,161 0 0 0 0 0 0 0 2,522 2,278 2,947 Others 14,970 163 2,388 56 3,994 2,692 1,519 2,739 877 3,770 208 1978 total 124,695 2,843 15,072 845 55,418 15,667 14,925 6,165 3,435 13,532 3,263 tlKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS pink salmon,CS =chum salmon,RT =ra i nbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. .r---J °,••l1li.5 10 Miles.:-:-:-~ o 5 - - _.10 15 Kllomelers ..... I W 0:> CJ .~ f3~ Rive,. 'Xo~\O<?,e o ../ SUSITNA RIVER AND MAJOR TRIBUTARIES FROM DEVIL CANYON TO DENALI HIGHWAY Figure 1.1-13.Susitna River and Major Tributaries from Devil Canyon to Denali Highway. Source:Exhibit E,Figure E.3.6. 0,...5 10 Miles.:-:::-~ o 5 ----10 15 Kllomelers Rive,. ..... I W 0:> SUSITNA RIVER AND MAJOR TRIBUTARIES FROM DEVIL CANYON TO DENALI HIGHWAY Figure 1.1-13.Susitna River and Major Tributaries from Devil Canyon to Denali Highway. Source:Exhibit E,Figure E.3.6. Tab 1e 1.1-8.Susitna Basin Sport Fish Harvest and Effort by Fishery and Species -1978, 1979,1980 and 1981 1978 t1 Days Locations Fished KS SS RS PS CS RT DV LT GR BB Wi 11 ow Creek 22,682 47 905 56 18,901 2,458 913 280 0 208 9 Caswell Creek Montana Creek 25,762 408 2,451 85 15,619 4,429 1,193 633 0 958 9 Sunshine Creek Clear (Chuni1na) Creek 5,040 12 2,200 28 2,074 1,912 1,501 1,817 0 859 27 Sheep Creek 11,869 256 478 14 6,981 1,697 470 108 0 461 18 Little Willow ..... Creek 5,687 0 151 28 3,142 1,015 334 63 0 334 0 I W Deshka River 9,111 850t2 1,798 0 697 0 3,634 0 0 579 0 '" Lake Creek 8,767 326t2 2,212 254 2,833 1,015 2,721 154 36 2,115 45 Alexander Creek 6,914 769t2 2,401 183 1,146 215 2,640 136 0 1,871 0 Talachulitna River 732 12t2 88 141 31 234 0 235 0 99 0 Lake Louise, Lake Susitna, Tyone River 13,161 0 0 0 0 0 0 0 2,522 2,278 2,947 Others 14,970 163 2,388 56 3,994 2,692 1,519 2,739 877 3,770 208 1978 total 124,695 2,843 15,072 845 55,418 15,667 14,925 6,165 3,435 13,532 3,263 tlKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8.Susitna Basin Sport Fish Harvest and Effort by Fishery and Species -1978, 1979,1980 and 1981 1978 t1 Days Locations Fished KS SS RS PS CS RT DV LT GR BB Wi 11 ow Creek 22,682 47 905 56 18,901 2,458 913 280 0 208 9 Caswell Creek Montana Creek 25,762 408 2,451 85 15,619 4,429 1,193 633 0 958 9 Sunshine Creek Clear (Chuni1na) Creek 5,040 12 2,200 28 2,074 1,912 1,501 1,817 0 859 27 Sheep Creek 11,869 256 478 14 6,981 1,697 470 108 0 461 18 Little Willow ..... Creek 5,687 0 151 28 3,142 1,015 334 63 0 334 0 I W Deshka River 9,111 850t2 1,798 0 697 0 3,634 0 0 579 0 '" Lake Creek 8,767 326t2 2,212 254 2,833 1,015 2,721 154 36 2,115 45 Alexander Creek 6,914 769t2 2,401 183 1,146 215 2,640 136 0 1,871 0 Talachulitna River 732 12t2 88 141 31 234 0 235 0 99 0 Lake Louise, Lake Susitna, Tyone River 13,161 0 0 0 0 0 0 0 2,522 2,278 2,947 Others 14,970 163 2,388 56 3,994 2,692 1,519 2,739 877 3,770 208 1978 total 124,695 2,843 15,072 845 55,418 15,667 14,925 6,165 3,435 13,532 3,263 tlKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8 (Cont'd) 1979t 1 Days Locations Fished KS SS RS PS CS RT DV LT GR BB Willow Creek 18,911 459 4 6 2 94 3,445 582 1,500 618 0 1,654 18 Caswell Creek 3,710 156 624 0 100 9 282 91 0 354 0 Montana Creek 22,621 312 1,735 346 2,472 745 1,536 527 0 791 9 Sunshine Creek 3,317 lOt2 774 157 700 55 382 264 0 0 45 Clear (Chunilna) Creek 5,125 312 1,248 31 645 355 1,373 827 0 1,045 9 Sheep Creek 6,728 10 462 31 2,418 682 573 127 0 645 64 Li tt 1e Wi 11 ow Creek 5,171 0 262 141 745 118 345 336 0 1,091 0 t-I Deshka River 13,236 2,811 973 0 109 0 3,182 0 0 1,463 82 , -Po Lake Creek 13,881 1,796 2,671 440 882 136 4,527 164 9 1,963 109 0 Alexander Creek 8,284 712 1,560 79 236 45 1,182 182 0 745 145 Talachulitna River 2,185 293 125 47 100 55 0 155 0 664 45 Lake Louise, Lake Susitna, Tyone River 12,199 0 0 0 0 0 0 0 2,618 2,936 2,363 Others 12,639 39 1,997 220 664 1,245 3,472 909 472 4,918 282 1979 total 128,007 6,910 12,893 1,586 12,516 4,072 18,354 4,200 3,099 13,342 3,171 tlKS =chinook salmon,55 =coho salmon,RS =sockeye salmon,P5 =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8 (Cont'd) 1979 tl Days Locations Fished KS SS RS PS CS RT DV LT GR BB Willow Creek 18,911 459 462 94 3,445 582 1,500 618 0 1,654 18 Caswell Creek 3,710 156 624 0 100 9 282 91 0 354 0 Montana Creek 22,621 312 1,735 346 2,472 745 1,536 527 0 791 9 Sunshine Creek 3,317 lO t2 774 157 700 55 382 264 0 0 45 Clear (Chunilna) Creek 5,125 312 1,248 31 645 355 1,373 827 0 1,045 9 Sheep Creek 6,728 10 462 31 2,418 682 573 127 0 645 64 Little Willow Creek 5,171 0 262 141 745 118 345 336 0 1,091 0 I-t Deshka River 13,236 2,811 973 0 109 0 3,182 0 0 1,463 82 , .p- Lake Creek 13,881 1,796 2,671 440 882 136 4,527 164 9 1,963 109 0 Alexander Creek 8,284 712 1,560 79 236 45 1,182 182 0 745 145 Talachulitna River 2,185 293 125 47 100 55 0 155 0 664 45 Lake Louise, Lake Susitna, Tyone River 12,199 0 0 0 0 0 0 0 2,618 2,936 2 , 3 6 3 Others 12,639 39 1,997 220 664 1,245 3,472 909 472 4,918 282 1979 total 128,007 6,910 12,893 1,586 12,516 4,072 18,354 4,200 3,099 13,342 3,171 tlKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8.(Cont'd) 1980 tl Days Locations Fi shed KS SS RS PS CS RT DV LT GR BB Willow Creek 29,011 289 1,207 83 23,638 989 1,168 636 0 1,868 0 Caswell Creek 4,963 215 1,124 77 1,663 19 154 83 0 353 26 Montana Creek 19,287 559 2,684 257 8,230 571 854 167 0 655 13 Sunshine Creek 5,208 132 1,534 116 2,408 225 193 39 0 0 39 Clear (Chunilna) Creek 4,388 172 661 6 622 385 950 751 0 1,348 32 Sheep Creek 8,041 45 t2 430 9 6,362 648 385 83 0 725 45 Little Willow ...... 32 t2 , Creek 8,190 494 77 6,420 270 353 122 0 1,156 0 J::> Deshka River 19,364 3,685 2,290 0 689 0 4,305 0 0 1,817 224 Lake Creek 8,325 775 2,351 267 2,101 69 2,144 121 9 1,972 0 Alexander Creek 6,812 1,438 999 52 809 121 1,945 353 0 1,145 0 Talachulitna River 2,542 121 491 112 276 17 379 982 0 1,713 0 Lake Louise, Lake Susitna, Tyone River 10,539 0 0 0 0 0 0 0 2,609 4,477 6,612 Others 12,216 45 t2 2,234 257 3,403 1,455 2,658 790 267 4,854 212 1980 total 138,886 7,389 16,499 1,304 56,621 4,759 15,488 4,127 2,876 22,083 7,203 "nKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8.(Cont'd) 1980 tl Days Locations Fished KS SS RS PS CS RT DV LT GR BB Willow Creek 29,011 289 1,207 83 23,638 989 1,168 636 0 1,868 0 Caswell Creek 4,963 215 1,124 77 1,663 19 154 83 0 353 26 Montana Creek 19,287 559 2,684 257 8,230 571 854 167 0 655 13 Sunshine Creek 5,208 132 1,534 116 2,408 225 193 39 0 0 39 Clear (Chunilna) Creek 4,388 172 661 6 622 385 950 751 0 1,348 32 Sheep Creek 8,041 45 t2 430 9 6,362 648 385 83 0 725 45 Little Willow ...... Creek 8,190 32 t2 494 77 6,420 270 353 122 0 1,156 , 0 J::> Deshka River 19,364 3,685 2,290 0 689 0 4,305 0 0 1,817 224 Lake Creek 8,325 775 2,351 267 2,101 69 2,144 121 9 1,972 0 Alexander Creek 6,812 1,438 999 52 809 121 1,945 353 0 1,145 0 Talachulitna River 2,542 121 491 112 276 17 379 982 0 1,713 0 Lake Louise, Lake Susitna, Tyone River 10,539 0 0 0 0 0 0 0 2,609 4,477 6,612 Others 12,216 45 t2 2,234 257 3,403 1,455 2,658 790 267 4,854 212 1980 total 138,886 7,389 16,499 1,304 56,621 4,759 15,488 4,127 2,876 22,083 7,203 ~KS =chinook salmon,SS coho salmon,RS =sockeye salmon,PS pink salmon,CS =chum salmon,RT =ra i nbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,and BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.3.6. Table 1.1-8.(Cont'd) 1981 tl Days KSt2LocationsFished KS SS RS PS CS RT DV LT GR BB Willow Creek 14,060 144 441 747 77 2,797 1,533 1 , 4 7 5 249 0 1,188 48 Caswell Creek 3,860 77 172 901 38 335 0 326 38 0 144 0 Montana Creek 16,657 239 422 2,261 182 1,782 805 1,111 240 0 891 0 Sunshine Creek 3,062 57 0 968 220 958 125 249 10 0 57 115 Clear (Chunilna) Creek 3,584 86 287 422 29 19 57 1,226 1,418 0 996 0 Sheep Creek 6,936 0 0 326 105 1,236 987 201 57 0 872 0 Little Willow ..... Creek 3,845 0 0 29 67 604 192 374 48 0 623 0 I.po Deshka River 13,248 738 2,031 632 0 19 0 3,631 10 0 1,255 96 N Lake Creek 6,471 163 632 1,035 211 412 48 2,874 67 19 1,600 29 Alexander Creek 6,892 278 843 891 67 57 10 2,290 287 0 1,130 29 Talachulitna River 1,378 57 0 240 172 29 0 0 0 0 479 0 Lake Louise, Lake Susitna, Tyone River 14,397 115 0 0 0 0 0 0 0 4,093 4,892 5,292 Others 7,850 277 0 939 115 412 450 3,851 814 287 7,089 57 1981 total 102,240 2,748 4,828 9,391 1,283 8,660 4,207 13,757 3,238 4,399 21,216 5,666 tl KS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,BB =burbot. f2Chinook less than 20 in. Source:Exhibit E,Table E.2.6. Table 1.1-8.(Cont'd) 1981 tl Days KSt2LocationsFished KS SS RS PS CS RT DV LT GR BB Willow Creek 14,060 144 441 747 77 2,797 1,533 1 , 4 7 5 249 a 1,188 48 Caswell Creek 3,860 77 172 901 38 335 a 326 38 a 144 a Montana Creek 16,657 239 422 2,261 182 1,782 805 1,111 240 a 891 a Sunshine Creek 3,062 57 a 968 220 958 125 249 10 a 57 115 Clear (Chunilna) Creek 3,584 86 287 422 29 19 57 1,226 1,418 a 996 a Sheep Creek 6,936 a a 326 105 1,236 987 201 57 a 872 a Little Willow ..... Creek 3,845 a a 29 67 604 192 374 48 a 623 a I.po Deshka River 13,248 738 2,031 632 a 19 a 3,631 10 a 1,255 96 N Lake Creek 6,471 163 632 1,035 211 412 48 2,874 67 19 1,600 29 Alexander Creek 6,892 278 843 891 67 57 10 2,290 287 a 1,130 29 Talachulitna River 1,378 57 a 240 172 29 a a a a 479 a Lake Louise, Lake Susitna, Tyone River 14,397 115 a a a a a a a 4,093 4,892 5,292 Others 7,850 277 a 939 115 412 450 3,851 814 287 7,089 57 1981 total 102,240 2,748 4,828 9,391 1,283 8,660 4,207 13,757 3,238 4,399 21,216 5,666 tlKS =chinook salmon,SS =coho salmon,RS =sockeye salmon,PS =pink salmon,CS =chum salmon,RT =rainbow trout, DV =Dolly Varden,LT =lake trout,GR =arctic grayling,BB =burbot. t2Chinook less than 20 in. Source:Exhibit E,Table E.2.6. 1-43Concentratedresearcheffortsarenecessarytobuildthetypeofinformationbasethatwillsupportanincreasedsalmonresourcebaseandallowappropriateandeffectivemanagementofit.Sustainedlong-termsupportofadequatestaffingandprojectbudgetsonthepartofthestateandthefishermenwillberequiredtorealizetheambitiousgoalssetoutintheplan.ThegoalsforthisplanaregiveninTable1.1-9,wherethenumbersareforallfivesalmonspeciescombined.Atargetharvestintheyear2000of12,000,000salmonseemsquiteoptimistic,buttotheextentthisplanissuccessfullyimplemented,itwillcounterbalancetneeffectsofincreasingfishingpressurepredictedinSec.1.2.1.3.2.Table1.1-9.GoalsoftheCookInletRegionalSalmonEnhancementPlanforEven-YearandOdd-YearRunsPresentProjectedProjectedResidualTarget1971-198019902000Gap2000AveragesStatusStatusStatusEven-yearrunHarvestablefish4,078,0006,892,00010,091,0001,909,00012,000,000Nonharvestablefish1,770,0002,984,0004,113,000955,0005,068,000Runstrength5,848,0009,876,00014,204,0002,864,00017,068,000Odd-yearrunHarvestablefish3,810,0006,092,000 9,091,0002,909,00012,000,000Nonharvestablefish1,720,0002,584,0003,613,0001,455,0005,068,000Runstrength5,530,0008,676,00012,704,0004,364,00017,068,000Source:CookInletRegionalPlanningTeam(1981).1.2ENVIRONMENTALIMPACTSThisappendixsectiondiscussestheanalyticalprocessesusedforestimatingimpactsoftheSusitnaprojectanditsalternativesontheaquaticresourcesdescribedinSec.1.1ofthisappendix.TheattachedenvironmentandexpectedimpactsaresummarizedintextSecs.3.1.4and4.1.4,respectively.Currentuncertaintyovertheaccuracyofmodelingreservoirandrivertemperatures,iceprocesses,andchangesinrivermorphologylendsuncertaintytodiscussionsofaquaticimpacts.Nonetheless,wehavetakenprojectionsbytheapplicant,temperedthemwithourownjudgmentsaboutwhatprobablyconstitutestypicalchangesduetotheproject,andconductedourfisheriesandaquaticecologicalanalysesinasquantativeamanneraspossible.DespitethedirectionofmostpreapplicationstudiestotheTalkeetnatoDevilCanyonreach,fisheriesimpactswillnotceaseatthejunctionwiththeChulitnaRiver.Totheextentpossiblewithexistingdata,wehaveextendedouranalysistoCookInlet.1.2.1WatanaDevelopment1.2.1.1PlantCommunitiesWatanaconstruction(includingbuildingofcofferdams,in-channeldredging,anddeforestation)willintroduceadditionalsiltintotheSusitna,butthequantitiesareestimated(Sec.4.1.3.2)tobenominalcomparedtoalreadyhighlevelsintheopenwaterconstructionseason.NodetectableimpactisanticipatedtoaquaticplantcommunitiesdownstreamofWatanawhicharepoorlydevelopedunderpresentsiltloadings.Aquaticplantsarealsopoorlydevelopedinclear-waterseasonsinwinterduetoiceandlightlimitation,andthuswouldbelittleaffectedbyincreasedsilt.1-43Concentratedresearcheffortsarenecessarytobuildthetypeofinformationbasethatwillsupportanincreasedsalmonresourcebaseandallowappropriateandeffectivemanagementofit.Sustainedlong-termsupportofadequatestaffingandprojectbudgetsonthepartofthestateandthefishermenwillberequiredtorealizetheambitiousgoalssetoutintheplan.ThegoalsforthisplanaregiveninTable1.1-9,wherethenumbersareforallfivesalmonspeciescombined.Atargetharvestintheyear2000of12,000,000salmonseemsquiteoptimistic,buttotheextentthisplanissuccessfullyimplemented,itwillcounterbalancetneeffectsofincreasingfishingpressurepredictedinSec.1.2.1.3.2.Table1.1-9.GoalsoftheCookInletRegionalSalmonEnhancementPlanforEven-YearandOdd-YearRunsPresentProjectedProjectedResidualTarget1971-198019902000Gap2000AveragesStatusStatusStatusEven-yearrunHarvestablefish4,078,0006,892,00010,091,0001,909,00012,000,000Nonharvestablefish1,770,0002,984,0004,113,000955,0005,068,000Runstrength5,848,0009,876,00014,204,0002,864,00017,068,000Odd-yearrunHarvestablefish3,810,0006,092,000 9,091,0002,909,00012,000,000Nonharvestablefish1,720,0002,584,0003,613,0001,455,0005,068,000Runstrength5,530,0008,676,00012,704,0004,364,00017,068,000Source:CookInletRegionalPlanningTeam(1981).1.2ENVIRONMENTALIMPACTSThisappendixsectiondiscussestheanalyticalprocessesusedforestimatingimpactsoftheSusitnaprojectanditsalternativesontheaquaticresourcesdescribedinSec.1.1ofthisappendix.TheattachedenvironmentandexpectedimpactsaresummarizedintextSecs.3.1.4and4.1.4,respectively.Currentuncertaintyovertheaccuracyofmodelingreservoirandrivertemperatures,iceprocesses,andchangesinrivermorphologylendsuncertaintytodiscussionsofaquaticimpacts.Nonetheless,wehavetakenprojectionsbytheapplicant,temperedthemwithourownjudgmentsaboutwhatprobablyconstitutestypicalchangesduetotheproject,andconductedourfisheriesandaquaticecologicalanalysesinasquantativeamanneraspossible.DespitethedirectionofmostpreapplicationstudiestotheTalkeetnatoDevilCanyonreach,fisheriesimpactswillnotceaseatthejunctionwiththeChulitnaRiver.Totheextentpossiblewithexistingdata,wehaveextendedouranalysistoCookInlet.1.2.1WatanaDevelopment1.2.1.1PlantCommunitiesWatanaconstruction(includingbuildingofcofferdams,in-channeldredging,anddeforestation)willintroduceadditionalsiltintotheSusitna,butthequantitiesareestimated(Sec.4.1.3.2)tobenominalcomparedtoalreadyhighlevelsintheopenwaterconstructionseason.NodetectableimpactisanticipatedtoaquaticplantcommunitiesdownstreamofWatanawhicharepoorlydevelopedunderpresentsiltloadings.Aquaticplantsarealsopoorlydevelopedinclear-waterseasonsinwinterduetoiceandlightlimitation,andthuswouldbelittleaffectedbyincreasedsilt. 1-44Effectsofreservoirfillingondownstreamreacheswillbesimilartothoseofconstruction(silt)andoperation(seesectionbelow).Asthereservoirisfilled,poorlydevelopedbenthicalgaeoftheinundatedriverwillbeprogressivelyreplacedbyanequallypoorplanktonpopulationinthenewreservoirwhichwillbeturbidduetobothriverinflowsanderosionofbanks.Duringlaterstagesoffillingandnormalreservoiroperation,themajorconsequencesofimpoundingtheSusitnaRiverwithWatanaDamwillbereductioninsummertimeturbidityanastabilizationofflows(seeSec.4.1.3.2),changesthattheFERCstaffjudgescouldsignificantlyincreasebenthicaquaticplantproductivityandthusfoodavailabilityforinvertebrateandfishfauna.Turbidityinsummerwillremainatlevelsthatwillrestrictlightpenetration,however,andthusinhibitmaximalprimaryproduction.Highstreamturbidityhasanegativeeffectonphotosynthesis(bylimitinglightpenetration)andondevelopmentofstreamperiphyton(byscourandcoveringrockysubstrates),whichreducesbenthicproductivityingeneral;floodinghasasimilareffect(Welch1952,Hynes1970).Informationisavailableintheliteratureontheeffectsofhydroelectricdevelopmentonbenthicplantproductionbelowdams.TheresultscanbeusedtoconsiderwhateffectsdecreasedturbiditiesandstabilizedflowsdownstreamofWatanaDammighthaveonbenthicplantproductionandutilization(Iwamotoetal.1978,Sorensonetal.1977,WardandStanford1979,Murphyetal.1981).SpecificinformationonthebeneficialeffectsofdamsinglacialsystemsonperiphytonisavailablefromtheU.S.northwest(Graybilletal.1979),Canada(Fredeen1977),andScandinavianstudies(Heggbergetinpress).IncreasedbenthicalgaeproductionontheSUbmergedriverbedwilloccurconcurrentlywithadecreaseinwettedsurfaceareaduetoreducedsummerflowsduringbothfillingandoperationofWatanadam(Sec.4.1.3.1).Althoughthebalanceisdifficulttoquantify,thestaffbelievesthattherewillbeanetincreaseinaquaticplantproductivitysimilartothatseenatotherglacialhydropowersites.BecauseoftheoverwhelminginfluencesoftheunregulatedChulitnaandTalkeetnariversonbothflowandturbiditydownstreamoftheconfluencesintheopenwaterseason,theFERCstafffeelsthatnodetectablechangeinaquaticplantcommunitieswillresult.AnychangesthatdooccurfromtheinputofclearSusitnaRiverwaterwilllikelybetowardincreasedproductivity.WithinWatanaReservoir,phytoplanktonproductioningeneralisexpectedtobemoderatelylowduetooligotrophicwaterquality(Sec.4.1.3.2)andseasonallyhighsiltloading.Settlingsiltwillprobablycarryalgalcellswithit,effectivelystrippingmuchofthepotentialpopulation(Avnimelechetal.1982).Planktonabundancesshouldpeakinspringwhenturbidityislowest,andbedominatedbydiatomspecies,asistypicalofmostcoollakesandreservoirs.Stratifiedflowscausedbytemperaturedifferenceswithinthereservoir,andaffectedbyoutletgatelocation,maycreatereservoirdetentiontimesthatvaryseasonallyinacomplexmannerandthatsignificantlyinfluencethedevelopmentofphytoplanktoncommunities.1.2.1.2InvertebrateCommunitiesIncrementalincreasesinsiltduringWatanaDamconstructionthatarewithintherangeofnaturalvariationcanbeexpected,asforbenthicalgaeproduction(Sec.1.2.1.1),tohaveminimalimpactonbenthicinvertebratecommunitiesintheSusitnaRiver.Reservoirfillingcanbeexpectedtohaveeffectssimilartothoseresultingfromreservoiroperation(below),withtheexceptionthatcoldtemperaturesinsummerwilllimittheanticipatedbenefitsderivedfromprogressivelyreducedsiltloads.Dependingonthedegreeofbankerosionandtherapiditywithwhichriversedimentsettlesinthenewreservoir,turbiditiesduringfillingmaycontinuetoinhibitbenthicinvertebratesdownstream.Inthereservoir,thepoorlydevelopedbenthicinvertebratecommunityintheSusitna,andthehigherpopulationsfoundinclear-watertributaries,willberemovedbytheinundation.Therewillbegradualreplacementofthesefaunasbybenthicspeciestypicalofreservoirsandbyreservoirzooplankton.DuringlaterperiodsoffillingandduringoperationofWatanaDam,areductioninsummertimeturbidityandstabilizationofriverflowscanbeexpectedtobebeneficialtothedevelopmentofbenthicinvertebratecommunitiesintheSusitnaRiverdownstreamofthedamsite(Hill1972;Bjornetal.1977;RosenbergandWiens1978).Despitelossesofwettedsurface(Sec.4.1.3.1),thestaffanticipatesanetincreaseinbenthicinvertebrates.Sedimentloadsimpactbenthicinvertebratepopulationsinthreeways:indirectly,byreducingprimaryproduction(Sec.1.2.1.1;e.g.,Hynes1970;WardandStanford1979);bycloggingrespiratorysurfacesand/ordislodgingorganisms(Iwamotoetal.1978);andbycreatingdepositsofsandandsiltintheintersticesofthesubstratewhichreducesaccessibilityofmicrohabitatsandlimitsintragravelwaterflow(CordoneandKelly1961;Iwamotoetal.1978;Sorensonetal.1977).Inparticular,thecompositionoffineslessthan0.850mmdiam(typicalofglacialstreams)maybeespeciallysignificant(Iwamotoetal.1978).1-44Effectsofreservoirfillingondownstreamreacheswillbesimilartothoseofconstruction(silt)andoperation(seesectionbelow).Asthereservoirisfilled,poorlydevelopedbenthicalgaeoftheinundatedriverwillbeprogressivelyreplacedbyanequallypoorplanktonpopulationinthenewreservoirwhichwillbeturbidduetobothriverinflowsanderosionofbanks.Duringlaterstagesoffillingandnormalreservoiroperation,themajorconsequencesofimpoundingtheSusitnaRiverwithWatanaDamwillbereductioninsummertimeturbidityanastabilizationofflows(seeSec.4.1.3.2),changesthattheFERCstaffjudgescouldsignificantlyincreasebenthicaquaticplantproductivityandthusfoodavailabilityforinvertebrateandfishfauna.Turbidityinsummerwillremainatlevelsthatwillrestrictlightpenetration,however,andthusinhibitmaximalprimaryproduction.Highstreamturbidityhasanegativeeffectonphotosynthesis(bylimitinglightpenetration)andondevelopmentofstreamperiphyton(byscourandcoveringrockysubstrates),whichreducesbenthicproductivityingeneral;floodinghasasimilareffect(Welch1952,Hynes1970).Informationisavailableintheliteratureontheeffectsofhydroelectricdevelopmentonbenthicplantproductionbelowdams.TheresultscanbeusedtoconsiderwhateffectsdecreasedturbiditiesandstabilizedflowsdownstreamofWatanaDammighthaveonbenthicplantproductionandutilization(Iwamotoetal.1978,Sorensonetal.1977,WardandStanford1979,Murphyetal.1981).SpecificinformationonthebeneficialeffectsofdamsinglacialsystemsonperiphytonisavailablefromtheU.S.northwest(Graybilletal.1979),Canada(Fredeen1977),andScandinavianstudies(Heggbergetinpress).IncreasedbenthicalgaeproductionontheSUbmergedriverbedwilloccurconcurrentlywithadecreaseinwettedsurfaceareaduetoreducedsummerflowsduringbothfillingandoperationofWatanadam(Sec.4.1.3.1).Althoughthebalanceisdifficulttoquantify,thestaffbelievesthattherewillbeanetincreaseinaquaticplantproductivitysimilartothatseenatotherglacialhydropowersites.BecauseoftheoverwhelminginfluencesoftheunregulatedChulitnaandTalkeetnariversonbothflowandturbiditydownstreamoftheconfluencesintheopenwaterseason,theFERCstafffeelsthatnodetectablechangeinaquaticplantcommunitieswillresult.AnychangesthatdooccurfromtheinputofclearSusitnaRiverwaterwilllikelybetowardincreasedproductivity.WithinWatanaReservoir,phytoplanktonproductioningeneralisexpectedtobemoderatelylowduetooligotrophicwaterquality(Sec.4.1.3.2)andseasonallyhighsiltloading.Settlingsiltwillprobablycarryalgalcellswithit,effectivelystrippingmuchofthepotentialpopulation(Avnimelechetal.1982).Planktonabundancesshouldpeakinspringwhenturbidityislowest,andbedominatedbydiatomspecies,asistypicalofmostcoollakesandreservoirs.Stratifiedflowscausedbytemperaturedifferenceswithinthereservoir,andaffectedbyoutletgatelocation,maycreatereservoirdetentiontimesthatvaryseasonallyinacomplexmannerandthatsignificantlyinfluencethedevelopmentofphytoplanktoncommunities.1.2.1.2InvertebrateCommunitiesIncrementalincreasesinsiltduringWatanaDamconstructionthatarewithintherangeofnaturalvariationcanbeexpected,asforbenthicalgaeproduction(Sec.1.2.1.1),tohaveminimalimpactonbenthicinvertebratecommunitiesintheSusitnaRiver.Reservoirfillingcanbeexpectedtohaveeffectssimilartothoseresultingfromreservoiroperation(below),withtheexceptionthatcoldtemperaturesinsummerwilllimittheanticipatedbenefitsderivedfromprogressivelyreducedsiltloads.Dependingonthedegreeofbankerosionandtherapiditywithwhichriversedimentsettlesinthenewreservoir,turbiditiesduringfillingmaycontinuetoinhibitbenthicinvertebratesdownstream.Inthereservoir,thepoorlydevelopedbenthicinvertebratecommunityintheSusitna,andthehigherpopulationsfoundinclear-watertributaries,willberemovedbytheinundation.Therewillbegradualreplacementofthesefaunasbybenthicspeciestypicalofreservoirsandbyreservoirzooplankton.DuringlaterperiodsoffillingandduringoperationofWatanaDam,areductioninsummertimeturbidityandstabilizationofriverflowscanbeexpectedtobebeneficialtothedevelopmentofbenthicinvertebratecommunitiesintheSusitnaRiverdownstreamofthedamsite(Hill1972;Bjornetal.1977;RosenbergandWiens1978).Despitelossesofwettedsurface(Sec.4.1.3.1),thestaffanticipatesanetincreaseinbenthicinvertebrates.Sedimentloadsimpactbenthicinvertebratepopulationsinthreeways:indirectly,byreducingprimaryproduction(Sec.1.2.1.1;e.g.,Hynes1970;WardandStanford1979);bycloggingrespiratorysurfacesand/ordislodgingorganisms(Iwamotoetal.1978);andbycreatingdepositsofsandandsiltintheintersticesofthesubstratewhichreducesaccessibilityofmicrohabitatsandlimitsintragravelwaterflow(CordoneandKelly1961;Iwamotoetal.1978;Sorensonetal.1977).Inparticular,thecompositionoffineslessthan0.850mmdiam(typicalofglacialstreams)maybeespeciallysignificant(Iwamotoetal.1978). 1-45Availablestudiesshowchangesinthefaunalcomposition,diversity,biomass,and/orabundanceofthebenthosinareasdownstreamofimpoundments(e.g.,Geen1974;Ward1976;WardandStanford1979;Graybilleta1.1979),althoughitisdifficulttodeterminespecificcausesofthechanges,suchasreducedsedimentloads.TheFERCstaffbelievessiltloadtobethepreprojectlimitingfactorforinvertebratesintheSusitna.BenthicproductiondownstreamofWatanacanbeexpectedtoincreaseafterthewaterclearsduetocompletionandfillingofWatanaDam.ThisresultwouldbeanticipatedbasedondifferencesinbenthicpopulationsreportedbetweentheglaciallyturbidSaukRiverandthenearbyimpoundedSkagitRiver,Washington,(Graybilleta1.1979).Speciesthatfilterreservoir-derivedplankton(e.g.,hydropsychids)maybeimportantinthereachesfromWatanatoDevilCanyon,whereasspeciesmoretypicalofclear-watertributariesmaydominateelsewhere.Increasedwinterturbidityisexpectedtohavenegligibleimpactwhencomparedtolowpreprojectbenthicpopulations.BecauseofthedominatinginfluencesofhighturbiditylevelsandflowfluctuationsintheChulitnaandTalkeetnarivers,regulationoftheSusitnaisnotexpectedtoresultinanysignificantincreaseinbenthicinvertebratepopulationsdownstreamoftheconfluenceofthethreerivers.ZooplanktoncanbeexpectedtodevelopintheWatanaReservoir,andthiscommunitymaybeanimportantsupplementtoinvertebratesintheSusitnaRiverbelowthedam.IntheSkagitRiver,Washington,reservoir-derivedcopepodsandc1adoceranswereimportantconstituentsofjuvenilesalmonstomachcontentsdownstream,becomingthedominantfooditeminApril(Graybilleta1.1979).WatanaReservoirisexpectedtobeoligotrophic,however(Sec.4.1.3.2),sozooplanktonpopulationsmaynotbeextensivelydeveloped.ThesparseriverinecommunityofbenthicinvertebratesinthereachesoftheSusitnatobeinundatedbytheWatanaReservoirisexpectedtobereplacedbyanequallysparsecommunityofOligochaetes,chironomids,pisidclams,andbenthicc1adoceranssuchasthoseobservedinScandinavianglaciallyfedreservoirs(Grimas1961,GrimasandNilsson1965).Biomasswillberestrictedbylargefluctuationsinwaterelevation(affectinglittoralzones)andheavysedimentationrates(affectingdeepzones).Themaximumbenthicbiomasscanbeexpectedimmediatelybelowthedrawdownlimit.PopulationsofanimalsnormallyabundantinthelittoralzonesofArcticlakes(e.g.,Gammaruslacustrusandmanygastropodsandinsectlarvae)willnotdevelopthere,butwilloccurinsmallernumbersbelowthedrawdownlimit.Filter-feedingpisidclamsandchironomidsthatnormallyinhabitprofunda1zonesofArcticlakeswillbekeptatlowlevels,eveninthezoneimmediatelybelowdrawdown,byinf10wingglacialsiltandsedimentserodingfromtheregulatedarea.TheuniformrateofemergenceofinsectsfromnormalArcticlakesthroughtheopenwaterseason(reflectingahighspeciesdiversity)willnotdevelopinWatanaReservoirduetothegeneralpaucityoflittoralspecies;insteadtherewillbeafewheavyemergences(Grimas1961).Thistimingisimportantforfishfoodsupply.Highorganiccontentsoffloodedsoilscanbeexpectedtofosterbenthiccladoceransinareaswithmoderateturbidity,butthesepopulationsshoulddiminishafterthefirstdecadeasthisorganicmatterisoxidizedand/orburiedbysilt.Thereshouldbeagenerallyhigherabundanceofbottomanimalsinthevicinitiesofclear-watertributariesthaninthemainSusitnachannel.1.2.1.3.FishCommunities1.2.1.3.1ConstructionPhaseConstructionofWatanaDam,fromsitepreparationthroughreservoirfilling,willimpactfisheryresourcesprimarilythroughadditionsofsilt,eliminationofriverinehabitatforresidentspecies(muchofwhichisconvertedtolakehabitat),changesindownstreamtemperature,andreductionsinsummerflows.SiltadditionduringconstructionofWatanaDamisjudgedtobeaminorincreasetoanalreadyhighglacialsiltloadinmostoftheopenwaterseason(Sec.4.1.3.2).Entryoferodedbankmaterials(whereheaviestparticleswilldeposit)andimpactstoriverinefishpopulationsbeyondthelocalconstructionsiteareexpectedtobeminor.Freeze-upandrestrictedconstructionactivityinwinterwillpreventsiltationduringthenormalclear-watermonths.Diminishedsiltloadingasconstructionproceedsandthereservoirfillswillhaveagenerallypositiveeffectondownstreamfishpopulations,asdetailedbelowundertheoperationphase.DegradationandlossofspawninghabitatbelowWatanaDamduringconstructionofthedamitselfduetoincreasedturbidityandsiltationwillbeminimalandlocalizedtothefirstseveralmilesbelowthedamsite.Nolossofsalmon-spawninghabitatisanticipatedsince,exceptforchinookduringsummerdroughts,salmondonotspawnupriverofDevilCanyon.Asthereservoirfills,riverinehabitatnowutilizedbyresidentfisheswillbepermanentlylostatthedamconstructionsiteandpermanentlytransformedtolakehabitatbetweenthedamandjustdownstreamofVeeCanyon.Thealterationwillincludelowerreachesofseveral1-45Availablestudiesshowchangesinthefaunalcomposition,diversity,biomass,and/orabundanceofthebenthosinareasdownstreamofimpoundments(e.g.,Geen1974;Ward1976;WardandStanford1979;Graybilleta1.1979),althoughitisdifficulttodeterminespecificcausesofthechanges,suchasreducedsedimentloads.TheFERCstaffbelievessiltloadtobethepreprojectlimitingfactorforinvertebratesintheSusitna.BenthicproductiondownstreamofWatanacanbeexpectedtoincreaseafterthewaterclearsduetocompletionandfillingofWatanaDam.ThisresultwouldbeanticipatedbasedondifferencesinbenthicpopulationsreportedbetweentheglaciallyturbidSaukRiverandthenearbyimpoundedSkagitRiver,Washington,(Graybilleta1.1979).Speciesthatfilterreservoir-derivedplankton(e.g.,hydropsychids)maybeimportantinthereachesfromWatanatoDevilCanyon,whereasspeciesmoretypicalofclear-watertributariesmaydominateelsewhere.Increasedwinterturbidityisexpectedtohavenegligibleimpactwhencomparedtolowpreprojectbenthicpopulations.BecauseofthedominatinginfluencesofhighturbiditylevelsandflowfluctuationsintheChulitnaandTalkeetnarivers,regulationoftheSusitnaisnotexpectedtoresultinanysignificantincreaseinbenthicinvertebratepopulationsdownstreamoftheconfluenceofthethreerivers.ZooplanktoncanbeexpectedtodevelopintheWatanaReservoir,andthiscommunitymaybeanimportantsupplementtoinvertebratesintheSusitnaRiverbelowthedam.IntheSkagitRiver,Washington,reservoir-derivedcopepodsandc1adoceranswereimportantconstituentsofjuvenilesalmonstomachcontentsdownstream,becomingthedominantfooditeminApril(Graybilleta1.1979).WatanaReservoirisexpectedtobeoligotrophic,however(Sec.4.1.3.2),sozooplanktonpopulationsmaynotbeextensivelydeveloped.ThesparseriverinecommunityofbenthicinvertebratesinthereachesoftheSusitnatobeinundatedbytheWatanaReservoirisexpectedtobereplacedbyanequallysparsecommunityofOligochaetes,chironomids,pisidclams,andbenthicc1adoceranssuchasthoseobservedinScandinavianglaciallyfedreservoirs(Grimas1961,GrimasandNilsson1965).Biomasswillberestrictedbylargefluctuationsinwaterelevation(affectinglittoralzones)andheavysedimentationrates(affectingdeepzones).Themaximumbenthicbiomasscanbeexpectedimmediatelybelowthedrawdownlimit.PopulationsofanimalsnormallyabundantinthelittoralzonesofArcticlakes(e.g.,Gammaruslacustrusandmanygastropodsandinsectlarvae)willnotdevelopthere,butwilloccurinsmallernumbersbelowthedrawdownlimit.Filter-feedingpisidclamsandchironomidsthatnormallyinhabitprofunda1zonesofArcticlakeswillbekeptatlowlevels,eveninthezoneimmediatelybelowdrawdown,byinf10wingglacialsiltandsedimentserodingfromtheregulatedarea.TheuniformrateofemergenceofinsectsfromnormalArcticlakesthroughtheopenwaterseason(reflectingahighspeciesdiversity)willnotdevelopinWatanaReservoirduetothegeneralpaucityoflittoralspecies;insteadtherewillbeafewheavyemergences(Grimas1961).Thistimingisimportantforfishfoodsupply.Highorganiccontentsoffloodedsoilscanbeexpectedtofosterbenthiccladoceransinareaswithmoderateturbidity,butthesepopulationsshoulddiminishafterthefirstdecadeasthisorganicmatterisoxidizedand/orburiedbysilt.Thereshouldbeagenerallyhigherabundanceofbottomanimalsinthevicinitiesofclear-watertributariesthaninthemainSusitnachannel.1.2.1.3.FishCommunities1.2.1.3.1ConstructionPhaseConstructionofWatanaDam,fromsitepreparationthroughreservoirfilling,willimpactfisheryresourcesprimarilythroughadditionsofsilt,eliminationofriverinehabitatforresidentspecies(muchofwhichisconvertedtolakehabitat),changesindownstreamtemperature,andreductionsinsummerflows.SiltadditionduringconstructionofWatanaDamisjudgedtobeaminorincreasetoanalreadyhighglacialsiltloadinmostoftheopenwaterseason(Sec.4.1.3.2).Entryoferodedbankmaterials(whereheaviestparticleswilldeposit)andimpactstoriverinefishpopulationsbeyondthelocalconstructionsiteareexpectedtobeminor.Freeze-upandrestrictedconstructionactivityinwinterwillpreventsiltationduringthenormalclear-watermonths.Diminishedsiltloadingasconstructionproceedsandthereservoirfillswillhaveagenerallypositiveeffectondownstreamfishpopulations,asdetailedbelowundertheoperationphase.DegradationandlossofspawninghabitatbelowWatanaDamduringconstructionofthedamitselfduetoincreasedturbidityandsiltationwillbeminimalandlocalizedtothefirstseveralmilesbelowthedamsite.Nolossofsalmon-spawninghabitatisanticipatedsince,exceptforchinookduringsummerdroughts,salmondonotspawnupriverofDevilCanyon.Asthereservoirfills,riverinehabitatnowutilizedbyresidentfisheswillbepermanentlylostatthedamconstructionsiteandpermanentlytransformedtolakehabitatbetweenthedamandjustdownstreamofVeeCanyon.Thealterationwillincludelowerreachesofseveral 1-46tributarystreams.ThemostupstreamreachofthereservoirtoabouttheOshetnaRiverwilllieintheregulatedzoneandwillremainriverineduringmonthsofreservoirdrawdown(winter,spring)andbecomelacustrinewhenthereservoirisstoringwater(summer,fall).Characteristicsofthereservoir'santicipatedfishpopulationsarediscussedunderreservoiroperation(below).TheFERCscopingprocessrevealedconcernthatwaterqualityalterationscausedbyimpoundmentoftheriverbyWatanaDam(andlater,DevilCanyon)couldcausesignificantdisorientationofadultspawnersintheyearsimmediatelyfollowingclosure.ThisdisorientationmightpreventasalmonfromsuccessfullylocatingtheSusitnaRiverattheconfluencewiththeChulitnaRiverorthesloughsandtributariesusedforspawning.Theabilityofsalmontoreturntothestreamoftheiroriginiswellknown,althoughintheSusitnaRiverthishomingisnormallyaccomplishedwithafairlylargedegreeofpreliminarywandering(ADF&G1981b,1983b).ExperiencesatotherhydroelectricprojectsonPacificcoastalriverssuggestthatthispotentialproblemmaybeminimal,eventhoughquantitativemethodstoevaluateitarenotavailable.Migrationsintotributariesmorethanafewkilometersdownstreamofnewdamsareusuallynotinterrupted.Furthermore,salmonrunstowatershedscutoffbyanewdamtypicallycongregateatthedambaseforseveralyearsfollowingclosureuntilthestockisdepleted.Thiscongregationindicatessuccessfulupstreamhomingtothevicinityofthedamdespiteanychangesinwaterqualityimposedbythenewreservoir.DuringfillingofWatanaReservoir,temperaturesintheSusitnaaboveTalkeetnamaybesufficientlylowinJune-Septembertoretardentryofmigratingadultsalmon.Salmonhavebeenknowntodelayupstreammigrationsuntilappropriatetemperatureshavebeenreached(Bell1973).Minimumtemperaturesreportedforactivemigrationofnorthernsalmonstocksare41°F(5°C)forpinksalmoninRussia,39°F(4°C)forcohoandchinook,36.5to39.2°F(2.5-4°C)forsockeye,and34.7°F(1.5°C)forchum,althoughmoststocksstudiedinlowerlatitudesshowhigher[43-45°F(6-7°C)]minimummigrationtemperatures.TherequirementsofSusitnaRiverstocksareunknown.TheFERCstaffhasestimatedthatmidsummertemperaturesoftheSusitnacouldbenear41to43°F(5-6°C)attheconfluencewiththeChulitna[basedon39°F(4°C)releasetemperatureandtherateofwarmingfromsunandtributariesexpectedbytheapplicant].ThiscontrastswithnormalmigrationtemperaturesintheSusitnaofabove50°F(10°C),althoughtheChulitnacommonlyhassummertemperaturesinthisrange(Table1.2-1).Greatermillingoffishattheconfluencecanbeexpected,withlargenumbersofadultschoosingthewarmerTalkeetnaratherthantheirnatalSusitna.Pink,chum,andcohosalmonspawningareasinthemainstembetweenWatanaDamandTalkeetnaareexpectedtobeadverselyaffectedbytheflowsproposedinthefillingscheduleforWatanaReservoir(Sec.4.1.1.4.1).Thesespawningareasaregenerallysmall,isolatedareasontherivermarginsorbehindvelocitybarriers.Lateralareasaremoresusceptibletochangesinflow.Thequalityofthesehabitatswillbedegradedthroughreduceddepthandvelocity;someareasmaybecompletelydewatered.Inaddition,somemainstemhabitatstillsuitableforspawningduringthesummerwillbedewateredintheearlyfallsincefallflowsatGoldCreekdroprapidlyunderthefillingschedule.Thisdewateringofspawninghabitatmayresultinadecreasedpercenthatchofdevelopingembryos,althoughsalmontendtospawninareasofgroundwaterupwellingwhichmaynotbedewateredattheloweredriverstagesinthefall.Decreasedmainstemflowswillresultindecreaseddepthsandvelocitiesinsomeside-channelhabitatandcompletedewateringofotherside-channelhabitat.Thisisexpectedtoalteroreliminatetheavailabilityorsuitabilityofsomeofthecurrentlyusedspawninghabitat.Itisunlikelythatnewspawningareaswillbecomeavailableinside-channelsunderthefillingflows.Side-channelhabitatswithastreambedelevationattheirupstreamendthatislowenoughtoconveywaterduringthelowflowsusedinthereservoirfillingprocessarecurrentlyexpectedtohavesubstratethatistoolargeforspawning.Itisunlikelythatthesubstrateintheseareaswouldchangeinatimespanasshortasthefillingschedule.Thus,theuseoftheseareasbyspawningfishwouldcontinuetobelimitedbysubstrate.SloughhabitatsbetweenWatanaDamandTalkeetnaareexpectedtobeofthespawninghabitattypemostsignificantlyaffectedbyfillingflows.Intheabsenceofmitigationmeasures,fillingflowsareexpectedtocauseaccessproblemsforreturningadultchumandsockeyesalmon.AnalysesbyFERCstaffindicatethattherewillbeacuteaccesslimitationsduringfillingflowsinsevenoutofsevensloughsaboveTalkeetnainJulyandinfiveofthesesevensloughsinAugustandSeptember(AppendixH)(Sec.4.1.1.4.2).Forsalmonthatdogainaccess,thespawningareawithinthesloughswillbereducedinareabecauseoflowermainstemflows.AnalysesbyFERCstaffindicatethatforninesloughsaboveTalkeetnathereductioninwettedsurfaceareaduringfillingflowswillbe58%inJuly,40%inAugust,and10%inSeptember(Sec.4.1.1.4.2).Inaddition,areductioninmainstemdischargemayreducetheamountofupwellingortheareainfluencedbyupwelling,resultinginreductionoreliminationofspawninghabitat(Sec.4.1.3.2).Finally,underfillingflows,increasedbeaveractivityandlackofdamremovalbyspring/summerhighflowsareexpectedtoinhibituseofupstreamsloughhabitatsforspawning.1-46tributarystreams.ThemostupstreamreachofthereservoirtoabouttheOshetnaRiverwilllieintheregulatedzoneandwillremainriverineduringmonthsofreservoirdrawdown(winter,spring)andbecomelacustrinewhenthereservoirisstoringwater(summer,fall).Characteristicsofthereservoir'santicipatedfishpopulationsarediscussedunderreservoiroperation(below).TheFERCscopingprocessrevealedconcernthatwaterqualityalterationscausedbyimpoundmentoftheriverbyWatanaDam(andlater,DevilCanyon)couldcausesignificantdisorientationofadultspawnersintheyearsimmediatelyfollowingclosure.ThisdisorientationmightpreventasalmonfromsuccessfullylocatingtheSusitnaRiverattheconfluencewiththeChulitnaRiverorthesloughsandtributariesusedforspawning.Theabilityofsalmontoreturntothestreamoftheiroriginiswellknown,althoughintheSusitnaRiverthishomingisnormallyaccomplishedwithafairlylargedegreeofpreliminarywandering(ADF&G1981b,1983b).ExperiencesatotherhydroelectricprojectsonPacificcoastalriverssuggestthatthispotentialproblemmaybeminimal,eventhoughquantitativemethodstoevaluateitarenotavailable.Migrationsintotributariesmorethanafewkilometersdownstreamofnewdamsareusuallynotinterrupted.Furthermore,salmonrunstowatershedscutoffbyanewdamtypicallycongregateatthedambaseforseveralyearsfollowingclosureuntilthestockisdepleted.Thiscongregationindicatessuccessfulupstreamhomingtothevicinityofthedamdespiteanychangesinwaterqualityimposedbythenewreservoir.DuringfillingofWatanaReservoir,temperaturesintheSusitnaaboveTalkeetnamaybesufficientlylowinJune-Septembertoretardentryofmigratingadultsalmon.Salmonhavebeenknowntodelayupstreammigrationsuntilappropriatetemperatureshavebeenreached(Bell1973).Minimumtemperaturesreportedforactivemigrationofnorthernsalmonstocksare41°F(5°C)forpinksalmoninRussia,39°F(4°C)forcohoandchinook,36.5to39.2°F(2.5-4°C)forsockeye,and34.7°F(1.5°C)forchum,althoughmoststocksstudiedinlowerlatitudesshowhigher[43-45°F(6-7°C)]minimummigrationtemperatures.TherequirementsofSusitnaRiverstocksareunknown.TheFERCstaffhasestimatedthatmidsummertemperaturesoftheSusitnacouldbenear41to43°F(5-6°C)attheconfluencewiththeChulitna[basedon39°F(4°C)releasetemperatureandtherateofwarmingfromsunandtributariesexpectedbytheapplicant].ThiscontrastswithnormalmigrationtemperaturesintheSusitnaofabove50°F(10°C),althoughtheChulitnacommonlyhassummertemperaturesinthisrange(Table1.2-1).Greatermillingoffishattheconfluencecanbeexpected,withlargenumbersofadultschoosingthewarmerTalkeetnaratherthantheirnatalSusitna.Pink,chum,andcohosalmonspawningareasinthemainstembetweenWatanaDamandTalkeetnaareexpectedtobeadverselyaffectedbytheflowsproposedinthefillingscheduleforWatanaReservoir(Sec.4.1.1.4.1).Thesespawningareasaregenerallysmall,isolatedareasontherivermarginsorbehindvelocitybarriers.Lateralareasaremoresusceptibletochangesinflow.Thequalityofthesehabitatswillbedegradedthroughreduceddepthandvelocity;someareasmaybecompletelydewatered.Inaddition,somemainstemhabitatstillsuitableforspawningduringthesummerwillbedewateredintheearlyfallsincefallflowsatGoldCreekdroprapidlyunderthefillingschedule.Thisdewateringofspawninghabitatmayresultinadecreasedpercenthatchofdevelopingembryos,althoughsalmontendtospawninareasofgroundwaterupwellingwhichmaynotbedewateredattheloweredriverstagesinthefall.Decreasedmainstemflowswillresultindecreaseddepthsandvelocitiesinsomeside-channelhabitatandcompletedewateringofotherside-channelhabitat.Thisisexpectedtoalteroreliminatetheavailabilityorsuitabilityofsomeofthecurrentlyusedspawninghabitat.Itisunlikelythatnewspawningareaswillbecomeavailableinside-channelsunderthefillingflows.Side-channelhabitatswithastreambedelevationattheirupstreamendthatislowenoughtoconveywaterduringthelowflowsusedinthereservoirfillingprocessarecurrentlyexpectedtohavesubstratethatistoolargeforspawning.Itisunlikelythatthesubstrateintheseareaswouldchangeinatimespanasshortasthefillingschedule.Thus,theuseoftheseareasbyspawningfishwouldcontinuetobelimitedbysubstrate.SloughhabitatsbetweenWatanaDamandTalkeetnaareexpectedtobeofthespawninghabitattypemostsignificantlyaffectedbyfillingflows.Intheabsenceofmitigationmeasures,fillingflowsareexpectedtocauseaccessproblemsforreturningadultchumandsockeyesalmon.AnalysesbyFERCstaffindicatethattherewillbeacuteaccesslimitationsduringfillingflowsinsevenoutofsevensloughsaboveTalkeetnainJulyandinfiveofthesesevensloughsinAugustandSeptember(AppendixH)(Sec.4.1.1.4.2).Forsalmonthatdogainaccess,thespawningareawithinthesloughswillbereducedinareabecauseoflowermainstemflows.AnalysesbyFERCstaffindicatethatforninesloughsaboveTalkeetnathereductioninwettedsurfaceareaduringfillingflowswillbe58%inJuly,40%inAugust,and10%inSeptember(Sec.4.1.1.4.2).Inaddition,areductioninmainstemdischargemayreducetheamountofupwellingortheareainfluencedbyupwelling,resultinginreductionoreliminationofspawninghabitat(Sec.4.1.3.2).Finally,underfillingflows,increasedbeaveractivityandlackofdamremovalbyspring/summerhighflowsareexpectedtoinhibituseofupstreamsloughhabitatsforspawning. 1-47Table1.2-1.ChangeinPotentialSummerGrowthofJuvenileSalmonintheTa1keetna-to-MouthReachDuetoFillingofWatanaReservoirandOperationofWatanaandDevilCanyonDamst1Watana+WatanaDevilCanyonMonthPreprojectFillingOperationTemperatures(av°F/oC)inlowerSusitnaJune51.8/1143.7/6.544.1/6.7July52.7/11.544.4/6.945.1/7.3August51.8/1145.1/7.346.0/7.8September45.5/7.542.1/5.642.8/6.0AccumulatedJune-Septembergrowth(g)4.281.792.00Reductionfrompreprojectgrowth(%)5853t1Ca1cu1ationswerebasedonassuminggrowthatmainstemtemperaturesandestimatingtemperaturesbysimpledilution.Accumulatedgrowthwascalculatedonthebasisofaninitial0.2-gfrythatdevelopedatweight-specificratespublishedforsockeyesalmon.AveragemonthlytemperaturesforthereachwerecalculatedfromaveragetemperatureandflowdatafortheChulitnaandTalkeetnariversandtheprojectedminimumflowsintheSusitnaRiverduringfillingandoperationofbothdams.TemperaturesfortheSusitnaRiverassumemaximumdownstreamwarmingfromreleasetemperatures(4°Cduringfilling).WarmingfromTalkeetnatothemouthhasnotbeenconsidered,butwouldchangelittleduetotheproject.Source:FERCstaff.Ifunmitigated,theseimpactswillreducethenumberofspawningchum,sockeye,andpinksalmoninthesloughsaboveTalkeetna,especiallyduringthesecondandthirdyearoffilling.Underaworst-casescenarioinwhichallsloughspawningislost,theapplicantestimatesthatthetotalsalmonrunenteringtheSusitnaRiverwouldbereducedbyanestimated11,840chum;9,200sockeye,and3,550pinksalmon,basedon1981and1982escapementdata(seeExhibitE.,Sec.2.3.2(b)[ii],SloughHabitat,andTableE.3.1.2).Theseestimatesassumeharvesttoescapementratiosof2.2:1;3.0:1;and3.8:1forchum,sockeye,andpinksalmon,respectively(Friese1975).TheFERCstaffhasreservationsaboutthisapplicationoftheratiosfromFriese(1975).TheseratiosarepresentedinAppendixIVofFriese(1975),whichhasthefollowingintroduction:"TheAlaskaDepartmentofFishandGamehasbeenrequestedtoassignmonetaryvaluestotheSusitnaRiversalmonstocksbytheCorpsofEngineers.Thesefigureswillprovideabasisformitigationactions.Totalescapementfiguresarenotavailableforthissystemanditisthereforedifficulttoassignavaluetothesalmonpopulations.ThefollowinghasbeencompiledbyCommercialFisheriesstaffbiologiststopartiallyfulfilltherequest.Itmustbeemphasizedthatfinalfiguresareonlyestimatesbasedonfeelingsof.biologistsfamiliarwiththeSusitnaBasinareaanddonotrepresentfacts."Inaddition,thereasoninganddatauponwhichtheratiosarebasedarenotprovided.Anotherdifficultyisthatthereapparentlyissomeconfusionconcerningthedefinitionoftheratio,whichFriese(1975)labels"return/spawner."TheapplicantinAppendixEinterpretsthistomean"harvest/escapement,"whereasGrogan(1983)interpretsthistomean"totalrun/escapement"andclaimstheapplicanthasmadeanerror.1-47Table1.2-1.ChangeinPotentialSummerGrowthofJuvenileSalmonintheTa1keetna-to-MouthReachDuetoFillingofWatanaReservoirandOperationofWatanaandDevilCanyonDamst1Watana+WatanaDevilCanyonMonthPreprojectFillingOperationTemperatures(av°F/oC)inlowerSusitnaJune51.8/1143.7/6.544.1/6.7July52.7/11.544.4/6.945.1/7.3August51.8/1145.1/7.346.0/7.8September45.5/7.542.1/5.642.8/6.0AccumulatedJune-Septembergrowth(g)4.281.792.00Reductionfrompreprojectgrowth(%)5853t1Ca1cu1ationswerebasedonassuminggrowthatmainstemtemperaturesandestimatingtemperaturesbysimpledilution.Accumulatedgrowthwascalculatedonthebasisofaninitial0.2-gfrythatdevelopedatweight-specificratespublishedforsockeyesalmon.AveragemonthlytemperaturesforthereachwerecalculatedfromaveragetemperatureandflowdatafortheChulitnaandTalkeetnariversandtheprojectedminimumflowsintheSusitnaRiverduringfillingandoperationofbothdams.TemperaturesfortheSusitnaRiverassumemaximumdownstreamwarmingfromreleasetemperatures(4°Cduringfilling).WarmingfromTalkeetnatothemouthhasnotbeenconsidered,butwouldchangelittleduetotheproject.Source:FERCstaff.Ifunmitigated,theseimpactswillreducethenumberofspawningchum,sockeye,andpinksalmoninthesloughsaboveTalkeetna,especiallyduringthesecondandthirdyearoffilling.Underaworst-casescenarioinwhichallsloughspawningislost,theapplicantestimatesthatthetotalsalmonrunenteringtheSusitnaRiverwouldbereducedbyanestimated11,840chum;9,200sockeye,and3,550pinksalmon,basedon1981and1982escapementdata(seeExhibitE.,Sec.2.3.2(b)[ii],SloughHabitat,andTableE.3.1.2).Theseestimatesassumeharvesttoescapementratiosof2.2:1;3.0:1;and3.8:1forchum,sockeye,andpinksalmon,respectively(Friese1975).TheFERCstaffhasreservationsaboutthisapplicationoftheratiosfromFriese(1975).TheseratiosarepresentedinAppendixIVofFriese(1975),whichhasthefollowingintroduction:"TheAlaskaDepartmentofFishandGamehasbeenrequestedtoassignmonetaryvaluestotheSusitnaRiversalmonstocksbytheCorpsofEngineers.Thesefigureswillprovideabasisformitigationactions.Totalescapementfiguresarenotavailableforthissystemanditisthereforedifficulttoassignavaluetothesalmonpopulations.ThefollowinghasbeencompiledbyCommercialFisheriesstaffbiologiststopartiallyfulfilltherequest.Itmustbeemphasizedthatfinalfiguresareonlyestimatesbasedonfeelingsof.biologistsfamiliarwiththeSusitnaBasinareaanddonotrepresentfacts."Inaddition,thereasoninganddatauponwhichtheratiosarebasedarenotprovided.Anotherdifficultyisthatthereapparentlyissomeconfusionconcerningthedefinitionoftheratio,whichFriese(1975)labels"return/spawner."TheapplicantinAppendixEinterpretsthistomean"harvest/escapement,"whereasGrogan(1983)interpretsthistomean"totalrun/escapement"andclaimstheapplicanthasmadeanerror. 1-48TributaryhabitatsbetweenDevilCanyonandTalkeetnaarenotexpectedtobedirectlyaffectedduringthefillingofWatanaReservoir,exceptforJackLong,Sherman,andDeadhorsecreeks(seeSec.4.1.3.1).Trihey(1983)indicatesthataccessibilityoftributariestoadultsalmonisnotlikelytobeaproblematthefillingflows,especiallyatPortageCreekandIndianRiver,whicharethetwomostproductivesalmontributariesupriverofTalkeetna.However,theamountofspawningintributaryhabitatmaybereducedbecausethenumbersofadultsalmonreachingthetributarymouthsmaybereduced.BelowTalkeetna,flowreductionsmayreducetheareaofspawninghabitat,sincethishabitattendstobelocatedonthelateralmarginsofthemainstemandinside-channelareas.Mostsalmon-spawningareasinthemainstemarelocatedinbroadorbraidedsegmentsthataremoresensitivetochangesinflow.Smallchangesinstagenearthethresholdvaluenecessarytoovertoptheupperendofthebraidedchannelscanpotentiallyresultinlargechangesintheavailabilityofspawninghabitatwithinthebraidedarea.SalmonandBeringciscospawninghabitatsmaybesubjecttochange,sincetheyoccurprimarilyintheupperportionofthissegmentfromRM75to81.Eulachonspawningareaswouldbesubjecttotheleastamountofchange,sincetheyoccurinthelowerpartofthereach,RM45to58.SpawninginsloughsandtributariesbelowTalkeetnaisnotexpectedtobesignificantlyaffectedduringfillingofWatanaReservoir.Duringfilling,thenormalwinterecologyofsalmonidswilllikelypersistintosummerintheDevilCanyontoTalkeetnareachoftheSusitnaRiverduetotheabnormallycold[39.2°F(4°C)releasesfromWatana.Ahypolimneticdischargeof37°F(4°C)atWatana(Sec.4.1.3.2)wouldwarmduringdownstreamflowthroughsolarheatingandtributaryinflow,butthiswillbeinsufficienttoevenapproachnormalsummertemperatures.ThewinterecologyofyoungsalmonidshasbeenintensivelystudiedoutsideofAlaskaandtheresultsofferindicationsofwhatcouldhappenintheSusitnaduringthethree-yearfillingperiod.ChinookandCohothatoverwinterinfreshwaterasfrytypicallychangefromterritorialdefenseandfeedingactivitytohidingincoverorindeepwaterasthetemperaturedropsbelowabout41°F(5°C)(Hartman1965;ChapmanandBjornn1969;BustardandNarver1975a,b).AtthemaximalratesofriverwarmingprojectedbytheapplicantinJune(ExhibitE.,Fig.E.2.176),this41°F(5°C)thresholdfornormalfishbehaviorisestimatedtobereachedatthemouthofDevilCanyon,whileatTalkeetna,rivertemperaturesareestimatedtobeslightlyabove42.8°F(6°C).Theseestimateshavehighuncertainty,sincetheFERCstaffextrapolatedfromthermalmodelingconductedforreservoirreleasetemperaturesotherthan39.2°F(4°C),andtherateofsummerheatingexpectedbytheapplicanthasbeenquestionedbythestaff(Sec.4.1.3.2).ThewholereachofriverfromWatanatoTalkeetnawouldappeartobeinagreyzoneofuncertaintyforfishbehavior39.2to42.8°F(4-6°C)betweenwinterinactivityandnormal,territorialfeedingbehavior.DuringmonthsbeforeandafterJune,whenriverheatingwouldbeless,thezoneofinduced"overwintering"wouldclearlybelarge.Eveniffishdofeed,growthratesatthesetemperaturesarelow,andFERCstaffcalculations(Sec.1.2.1.3.2,Growth-TemperatureRelationships)showlittleaccumulatedbodyweight(lessthanone-quarterofthenormalJune-Sepetembergrowthincrement).Thedegreetowhichsloughtemperatureswillprovidewarmwaterrefugesforyoungfishandallowmorenormalgrowthishighlyuncertain.ItislikelythattherewillbeaninsignificantamountofsalmonfrygrowthintheDevilCanyontoTalkeetnareachduringthesummersofWatanafilling.Thiseffectwillbefeltbyresidentfishesalso,anddifferentlybyeachofthefivesalmonspecies.Chumandpinksalmonthatemergefromreddsinspring,emigraterapidlyinnormallycoolflowsofearlysummer,anddependonlowerriverandestuarinerearingformuchoftheirjuvenilegrowthwouldbeaffectedminimally.SockeyeapparentlyalsoleavethereachaboveTalkeetnarapidlyandwouldshowminimaleffect.Cohoandchinook,however,rearforayearormoreintheriverenvironmentbeforedescendingtotheocean,andusethemainstemforoverwintering.Thus,morethanoneyear-classwouldbeintheriverduringabnormalsummertemperatures.Theywouldbelocatedthereasaresultofoverwinteringbehaviorthepreviouswinter,andtheywoulddependonsummerrearingforattainingsizesappropriateforemigration.Theywouldbeaffectedmostseverely.Theextenttowhichwarmersloughsandtributarymouthswouldprovideenoughsuitable,alternativehabitattoanonwarmingmainstemisdifficulttojudge.DownstreamoftheconfluencewiththeChulitnaandTalkeetnarivers,growthratesofjuvenilesalmonandresidentspecieswillalsobesuppressedbycooltemperatures.TheFERCstaffestimatesareductioninaccumulatedJune-Septembergrowthinthisreachbyabout50to60%comparedtopotentialgrowthatpreprojecttemperatures(Table1.2-1).Thesecalculationstakejntoaccountthecontributionstotheanticipatedmainstemtemperaturesandflowsbyeachofthethreerivers.AsintheDevilCanyontoTalkeetnareach,theimpactwouldbe1-48TributaryhabitatsbetweenDevilCanyonandTalkeetnaarenotexpectedtobedirectlyaffectedduringthefillingofWatanaReservoir,exceptforJackLong,Sherman,andDeadhorsecreeks(seeSec.4.1.3.1).Trihey(1983)indicatesthataccessibilityoftributariestoadultsalmonisnotlikelytobeaproblematthefillingflows,especiallyatPortageCreekandIndianRiver,whicharethetwomostproductivesalmontributariesupriverofTalkeetna.However,theamountofspawningintributaryhabitatmaybereducedbecausethenumbersofadultsalmonreachingthetributarymouthsmaybereduced.BelowTalkeetna,flowreductionsmayreducetheareaofspawninghabitat,sincethishabitattendstobelocatedonthelateralmarginsofthemainstemandinside-channelareas.Mostsalmon-spawningareasinthemainstemarelocatedinbroadorbraidedsegmentsthataremoresensitivetochangesinflow.Smallchangesinstagenearthethresholdvaluenecessarytoovertoptheupperendofthebraidedchannelscanpotentiallyresultinlargechangesintheavailabilityofspawninghabitatwithinthebraidedarea.SalmonandBeringciscospawninghabitatsmaybesubjecttochange,sincetheyoccurprimarilyintheupperportionofthissegmentfromRM75to81.Eulachonspawningareaswouldbesubjecttotheleastamountofchange,sincetheyoccurinthelowerpartofthereach,RM45to58.SpawninginsloughsandtributariesbelowTalkeetnaisnotexpectedtobesignificantlyaffectedduringfillingofWatanaReservoir.Duringfilling,thenormalwinterecologyofsalmonidswilllikelypersistintosummerintheDevilCanyontoTalkeetnareachoftheSusitnaRiverduetotheabnormallycold[39.2°F(4°C)releasesfromWatana.Ahypolimneticdischargeof37°F(4°C)atWatana(Sec.4.1.3.2)wouldwarmduringdownstreamflowthroughsolarheatingandtributaryinflow,butthiswillbeinsufficienttoevenapproachnormalsummertemperatures.ThewinterecologyofyoungsalmonidshasbeenintensivelystudiedoutsideofAlaskaandtheresultsofferindicationsofwhatcouldhappenintheSusitnaduringthethree-yearfillingperiod.ChinookandCohothatoverwinterinfreshwaterasfrytypicallychangefromterritorialdefenseandfeedingactivitytohidingincoverorindeepwaterasthetemperaturedropsbelowabout41°F(5°C)(Hartman1965;ChapmanandBjornn1969;BustardandNarver1975a,b).AtthemaximalratesofriverwarmingprojectedbytheapplicantinJune(ExhibitE.,Fig.E.2.176),this41°F(5°C)thresholdfornormalfishbehaviorisestimatedtobereachedatthemouthofDevilCanyon,whileatTalkeetna,rivertemperaturesareestimatedtobeslightlyabove42.8°F(6°C).Theseestimateshavehighuncertainty,sincetheFERCstaffextrapolatedfromthermalmodelingconductedforreservoirreleasetemperaturesotherthan39.2°F(4°C),andtherateofsummerheatingexpectedbytheapplicanthasbeenquestionedbythestaff(Sec.4.1.3.2).ThewholereachofriverfromWatanatoTalkeetnawouldappeartobeinagreyzoneofuncertaintyforfishbehavior39.2to42.8°F(4-6°C)betweenwinterinactivityandnormal,territorialfeedingbehavior.DuringmonthsbeforeandafterJune,whenriverheatingwouldbeless,thezoneofinduced"overwintering"wouldclearlybelarge.Eveniffishdofeed,growthratesatthesetemperaturesarelow,andFERCstaffcalculations(Sec.1.2.1.3.2,Growth-TemperatureRelationships)showlittleaccumulatedbodyweight(lessthanone-quarterofthenormalJune-Sepetembergrowthincrement).Thedegreetowhichsloughtemperatureswillprovidewarmwaterrefugesforyoungfishandallowmorenormalgrowthishighlyuncertain.ItislikelythattherewillbeaninsignificantamountofsalmonfrygrowthintheDevilCanyontoTalkeetnareachduringthesummersofWatanafilling.Thiseffectwillbefeltbyresidentfishesalso,anddifferentlybyeachofthefivesalmonspecies.Chumandpinksalmonthatemergefromreddsinspring,emigraterapidlyinnormallycoolflowsofearlysummer,anddependonlowerriverandestuarinerearingformuchoftheirjuvenilegrowthwouldbeaffectedminimally.SockeyeapparentlyalsoleavethereachaboveTalkeetnarapidlyandwouldshowminimaleffect.Cohoandchinook,however,rearforayearormoreintheriverenvironmentbeforedescendingtotheocean,andusethemainstemforoverwintering.Thus,morethanoneyear-classwouldbeintheriverduringabnormalsummertemperatures.Theywouldbelocatedthereasaresultofoverwinteringbehaviorthepreviouswinter,andtheywoulddependonsummerrearingforattainingsizesappropriateforemigration.Theywouldbeaffectedmostseverely.Theextenttowhichwarmersloughsandtributarymouthswouldprovideenoughsuitable,alternativehabitattoanonwarmingmainstemisdifficulttojudge.DownstreamoftheconfluencewiththeChulitnaandTalkeetnarivers,growthratesofjuvenilesalmonandresidentspecieswillalsobesuppressedbycooltemperatures.TheFERCstaffestimatesareductioninaccumulatedJune-Septembergrowthinthisreachbyabout50to60%comparedtopotentialgrowthatpreprojecttemperatures(Table1.2-1).Thesecalculationstakejntoaccountthecontributionstotheanticipatedmainstemtemperaturesandflowsbyeachofthethreerivers.AsintheDevilCanyontoTalkeetnareach,theimpactwouldbe 1-49greatesttochinook,coho,andsockeyesalmonandresidentspecies,withminimaleffectstothespring-emigratingpinkandchumsalmon,andwouldbeamelioratedtoanunknownextentbyfishconcentratinginwarmersloughs.1.2.1.3.2OperationPhaseNumerousissueshavearisenregardingmaintenanceoffishpopulations,especiallysalmon,intheSusitnaRiverwiththeSusitnahydroelectricproject.Thissectionemphasizesthoseissues,whichareorganizedaccordingtomajorlifestagesofanadromousfish.UpstreamMigrationandSpawningofSalmonBetweenDevilCanyonandTalkeetna,theprimaryimpactsonsalmonspawningduringtheoperationphaseoftheproposedprojectwillbesimilarto,butlessseverethan,thosediscussedfortheconstructionphase.Thedecreasedsummerflowswillcauseaccessproblemsforadultsalmonenteringsloughspawninghabitatsandwillreducetheareaofsuitablespawninghabitatwithinthesloughs.AnalysesbyFERCstaffindicatethatforninesloughsaboveTalkeetnathefrequencyofoccurrenceofacuteaccesslimitationsduringoperationofWatanawillbe63%inJuly,52%inAugust,and56%inSeptember.Theseanalysesalsoindicateareductioninwettedsurfaceareainninesloughsof53%inJuly,36%inAugust,and9%inSeptember(Sec.4.1.1.4.2).Someofthepresentsidechannelswillbecomesloughsunderthesummerflowregime;however,adequateinformationisnotcurrentlyavailabletopermitananalysisoftheextenttowhichthischangemayprovidenewspawninghabitat.Ifunmitigated,andassumingthataccesstoandavailabilityofsuitablespawninghabitatarecurrentlylimitingsalmonproduction,decreasedsummerflowswillreducethenumberofchum,sockeye,andpinksalmonspawninginthesloughsupstreamfromTalkeetna.Theworst-casescenariowouldbetotallossofsloughspawninghabitatinthisreach,withanestimatedreductioninthetotalrunsizeforthesethreespecies,asdiscussedfortheconstructionphase(Sec.B.2.1.3.1).TributaryhabitatsbetweenDevilCanyonandTalkeetnaarenotexpectedtobedirectlyaffectedduringoperationoftheWatanaproject,exceptforJackLong,Sherman,andDeadhorsecreeks(seeSec.4.1.3.1);salmonhavenotbeenobservedspawninginanyofthesethreecreeks.Trihey(1983)indicatesthataccessabilityoftributariestoadultsalmonisnotlikelytobeaproblemduringJunethroughSeptemberduringtheoperationphase,especiallyatPortageCreekandIndianRiver,whicharethetwomostproductivesalmontributariesupriverofTalkeetna.DownriverfromTalkeetna(ascomparedtoupriver),operationofWatanaaloneisexpectedtohavelessofanimpactonspawninginallhabitattypesbecausetheprimarywater-relatedvariablesinfluencingspawning(i.e.,flow,temperature,turbidity,andsiltation)willbechangedtoalesserextentrelativetopreprojectconditions(seeSec.4.1.3.1).Forexample,thetotalwettedsurfaceareaofRabideauxSloughnearSunshinewillbedecreasedbyonly22%onaverageinJuneandJuly(seeSec.4.1.3.1onPhysicalHabitatAvailability).Temperaturechangesfromrivertotributary.Temperaturedifferencesbetweenatributaryandamainstemmigrationcorridorhavebeenknowntodelayspawningmigrations(e.g.,MajorandMighell1966),andthiseffecthasbeensuggestedfortheSusitnaRiveraftermainstemtemperatureshavebeenaltered.ReviewofavailabletemperaturepredictionsfortheSusitna,withWatanaDamoperatingandthecircumstancesofreportedmigrationeffectselsewhere,indicateslittlepotentialforimpededmigrationfromtheSusitnaintotributarystreams.Documentedmigrationblockageshavebeentheresultoftributarytemperaturesexceedingupperavoidancetemperatures(Coutant1977)ratherthanbeingduetothedifferentialoftemperaturewiththemainstem.ThissituationcontrastswiththechangedthermalrelationshipsattheSusitnaRiver,wheretributarytemperatureswillnotberaisedbutwherewillbesomereductionofmainstemtemperaturesinearlysummer.Thermalregimesofbothtributariesandmainstemwillremaininthenormalphysiologicalandbehavioralrangeduringnormalreservoiroperation.Gassupersaturation.Supersaturateddissolvedgasesinwater(Sec.4.1.3.2)aregenerallylethaltosalmonidfisheswhensaturationvaluesreachabout110%ofsurfaceatmosphericpressure(NationalAcademyofSciences/NationalAcademyofEngineering1973).Conevalvesproposedfortheoutletfacilitiestodissipatemomentumshouldreducethelikelihoodofsupersaturationvaluesexceeding110%.Therearenosimilarcontrolsproposedforthespillway.InfrequentuseofthespillwaycanbeexpectedtocauseextensivefishmortalitiesintheriverdownstreamatleasttotheChulitnaconfluence.Becausewaterpressureatdepthcompensatesphysicallyforsupersaturation,floodflowsshouldprovideadditionaldepthinwhichmigratingadultscanfindrefuge.Atgreatestriskwouldbejuvenilefishesthatfrequentshallowshorelinezones.1-49greatesttochinook,coho,andsockeyesalmonandresidentspecies,withminimaleffectstothespring-emigratingpinkandchumsalmon,andwouldbeamelioratedtoanunknownextentbyfishconcentratinginwarmersloughs.1.2.1.3.2OperationPhaseNumerousissueshavearisenregardingmaintenanceoffishpopulations,especiallysalmon,intheSusitnaRiverwiththeSusitnahydroelectricproject.Thissectionemphasizesthoseissues,whichareorganizedaccordingtomajorlifestagesofanadromousfish.UpstreamMigrationandSpawningofSalmonBetweenDevilCanyonandTalkeetna,theprimaryimpactsonsalmonspawningduringtheoperationphaseoftheproposedprojectwillbesimilarto,butlessseverethan,thosediscussedfortheconstructionphase.Thedecreasedsummerflowswillcauseaccessproblemsforadultsalmonenteringsloughspawninghabitatsandwillreducetheareaofsuitablespawninghabitatwithinthesloughs.AnalysesbyFERCstaffindicatethatforninesloughsaboveTalkeetnathefrequencyofoccurrenceofacuteaccesslimitationsduringoperationofWatanawillbe63%inJuly,52%inAugust,and56%inSeptember.Theseanalysesalsoindicateareductioninwettedsurfaceareainninesloughsof53%inJuly,36%inAugust,and9%inSeptember(Sec.4.1.1.4.2).Someofthepresentsidechannelswillbecomesloughsunderthesummerflowregime;however,adequateinformationisnotcurrentlyavailabletopermitananalysisoftheextenttowhichthischangemayprovidenewspawninghabitat.Ifunmitigated,andassumingthataccesstoandavailabilityofsuitablespawninghabitatarecurrentlylimitingsalmonproduction,decreasedsummerflowswillreducethenumberofchum,sockeye,andpinksalmonspawninginthesloughsupstreamfromTalkeetna.Theworst-casescenariowouldbetotallossofsloughspawninghabitatinthisreach,withanestimatedreductioninthetotalrunsizeforthesethreespecies,asdiscussedfortheconstructionphase(Sec.B.2.1.3.1).TributaryhabitatsbetweenDevilCanyonandTalkeetnaarenotexpectedtobedirectlyaffectedduringoperationoftheWatanaproject,exceptforJackLong,Sherman,andDeadhorsecreeks(seeSec.4.1.3.1);salmonhavenotbeenobservedspawninginanyofthesethreecreeks.Trihey(1983)indicatesthataccessabilityoftributariestoadultsalmonisnotlikelytobeaproblemduringJunethroughSeptemberduringtheoperationphase,especiallyatPortageCreekandIndianRiver,whicharethetwomostproductivesalmontributariesupriverofTalkeetna.DownriverfromTalkeetna(ascomparedtoupriver),operationofWatanaaloneisexpectedtohavelessofanimpactonspawninginallhabitattypesbecausetheprimarywater-relatedvariablesinfluencingspawning(i.e.,flow,temperature,turbidity,andsiltation)willbechangedtoalesserextentrelativetopreprojectconditions(seeSec.4.1.3.1).Forexample,thetotalwettedsurfaceareaofRabideauxSloughnearSunshinewillbedecreasedbyonly22%onaverageinJuneandJuly(seeSec.4.1.3.1onPhysicalHabitatAvailability).Temperaturechangesfromrivertotributary.Temperaturedifferencesbetweenatributaryandamainstemmigrationcorridorhavebeenknowntodelayspawningmigrations(e.g.,MajorandMighell1966),andthiseffecthasbeensuggestedfortheSusitnaRiveraftermainstemtemperatureshavebeenaltered.ReviewofavailabletemperaturepredictionsfortheSusitna,withWatanaDamoperatingandthecircumstancesofreportedmigrationeffectselsewhere,indicateslittlepotentialforimpededmigrationfromtheSusitnaintotributarystreams.Documentedmigrationblockageshavebeentheresultoftributarytemperaturesexceedingupperavoidancetemperatures(Coutant1977)ratherthanbeingduetothedifferentialoftemperaturewiththemainstem.ThissituationcontrastswiththechangedthermalrelationshipsattheSusitnaRiver,wheretributarytemperatureswillnotberaisedbutwherewillbesomereductionofmainstemtemperaturesinearlysummer.Thermalregimesofbothtributariesandmainstemwillremaininthenormalphysiologicalandbehavioralrangeduringnormalreservoiroperation.Gassupersaturation.Supersaturateddissolvedgasesinwater(Sec.4.1.3.2)aregenerallylethaltosalmonidfisheswhensaturationvaluesreachabout110%ofsurfaceatmosphericpressure(NationalAcademyofSciences/NationalAcademyofEngineering1973).Conevalvesproposedfortheoutletfacilitiestodissipatemomentumshouldreducethelikelihoodofsupersaturationvaluesexceeding110%.Therearenosimilarcontrolsproposedforthespillway.InfrequentuseofthespillwaycanbeexpectedtocauseextensivefishmortalitiesintheriverdownstreamatleasttotheChulitnaconfluence.Becausewaterpressureatdepthcompensatesphysicallyforsupersaturation,floodflowsshouldprovideadditionaldepthinwhichmigratingadultscanfindrefuge.Atgreatestriskwouldbejuvenilefishesthatfrequentshallowshorelinezones. I-50PotentialsalmonenhancementaboveDevilCanyon.BecausetheSusitnaRiveranditstributariesupstreamofDevilCanyonarenaturallyinaccessibletosalmonmigrations(exceptforrareincursiontotributariesimmediatelyupstreamduringdroughtflowsinJune-August).thedesirabilityofinterventiontoenhancemigrationshasbeenexplored.TheAlaskaDepartmentofFishandGame'sFisheriesRehabilitation.Enhancement.andDevelopment(FRED)Divisionassessedfeasibilityandcostsofsuchenhancement.Althoughtheinternalreportshavenotbeenmadeavailable.theconclusionwasreachedthatupriverexpansionaboveDevilCanyonofanadromoussalmonpopulationswasnotpracticable.ReducedsummerflowswithWatanaDamoperatingcouldremovethebarrierofturbulentflowsinDevilCanyonandprovidepermenantaccessforadultsalmontoChinook.Cheechoko.Devil.Tsusena.andnumeroussmallercreeks.ThischangewouldopenawatershedareatotributarysalmonspawningthatwouldbeapproximatelyequalinsizetobothIndianRiverandPortageCreek.IncubationDuringtheJuly-Aprilperiod.salmoneggsareincubatingingravelsofsloughsandofsomesidechannels.Changesinriverflowandtemperatureduringthistimecanbeexpectedtohavesomeimpactonincubationsuccess.Theprincipalsourcesofimpactarephysicaldewateringandreducedintergravelwaterflowderivedfromthemainstem(whicharetreatedinAppendixH)andbiologicalchangesinincubationrateandemergencetimingcausedbyalteredtemperaturesandsmotheringofeggsbysilt(asdiscussedbelow).Redddewatering.OperationofWatanaDamhasbeenplannedtoavoidapower-peakingmodeofhydroelectricgenerationwhichwouldrequirefrequentchangesintheamountofwaterreleasedthroughturbinestothefree-flowingSusitnaRiver.Short-term.rapidfluctuationsindownstreamflowhavebeenofconcernatotherhydroelectricsites.especiallyforimpactsondevelopingsalmoneggs.embryos.andalevinsinrivergravels.Whensalmonspawnduringasustainedhighdischarge.subsequentreductionofflowmayexposespawningbedsanddewaterredds.TheFERCstaffhasreviewedfieldstudiesatseveralhydroelectricsitesintheU.S.whichhaveexaminedtheeffectsofdewateringredds(WittyandThompson1974;Stillwelletale1977;Bauersfield1978;Parametrixetale1979;McMullinandGraham1981)andexperimentalstudiesofdewateredartificialreddscontainingchinooksalmon.Thesestudieshaveidentifieddifferingvulnerabilitytodamageamongdevelopmentalstages(Beckeretale1982andunpublisheddata).BecausetheSustinaRiverisusedformainstemandsloughspawningbyallPacificsalmonspeciesexceptchinook.powerpeakingwouldhaveputspawningareasatrisk.Theproposedlimitationofreleasestotherivertothoseofabase-loadoperationconstitutesaneffectivefishconservationmeasurecomparedtoapeakingmodeofoperation.SomeredddewateringmayoccurinwinteraboveShermanduringreservoiroperations.There.normalicecoverisnotexpectedtoformduetowarmreservoirreleases.andpreprojecticedammingwillnotbeavailabletofloodcertainspawningsloughs.Theamountofsalmonproductionaffectedwillbesmall.amountingtofewerthan100spawningadults.Eggincubationratesatalteredtemperatures.ThelargestoragevolumeofWatanaReservoirwillcauseoutlettemperaturesduringoperationtobewarmerthannormal(preproject)inthefallandwinterincubationperiod.althoughthemeanannualrivertemperaturewithWatanaalonewillbeaboutthesameaspreproject.Developmentratesaretemperature-dependentandareimportantforsalmonbecauseprematureemergenceandearlyemigrationinducedbyabnormallywarmtemperatureshavebeenshowntoreducesurvivaltotheadultstage(Vernon1958;Taylor1980).whereasabnormallylowtemperaturescanpreventnormaldevelopment.Amajorfactorinreducedsurvivalofearlyemergingfryisbelievedtobetheirencounterwithcoldtemperatures.inadequateseasonalfooddevelopment.andhighpredationratesintheestuarineandmarineenvironments(Gilhousen1962).Earlier-emergingfrytendtobesmallerthanlater-emergingonesinlaboratorystudiesandfieldcollections(Graybilletale1979).whichmaymakethemmorevulnerabletomanysourcesofmortality.Thestaffhasevaluatedtheincubationperiodofsalmoneggsusingcumulative"temperatureunits"ordegree-daysfromtheliterature(whereadailytemperatureunitequals1°Cabovefreezingfora24-hperiod)andregressionequationspublishedbyWangaardandBurger(1983)forincubationrateversustemperatureforSusitnastocksofchumandsockeyesalmon.Althoughtemperatureunitcharacterizationisnotcompletelysatisfactory[see.forexample.objectionsbyBattle(1944)andMarr(1966).andevidenceofcompensatoryratechangesthattendtominimizeeffectsofalteredtemperaturesfoundbyGraybilletale(1979)].Ithasprovenusefulinhatcherymanagement(Piperetale1982).laboratoryinvestigations(e.g••Olsonetale1970).andimpactassessmentsofhydroelectricprojects(Graybilletale1979).Temperatureunitstohatchingandemergenceareavailableforeachsalmonspecies.basedlargelyonhatcheryexperiencesinOregon.Washington.andBritishColumbia(Table1.1-3).TheSusitnastocksofchumandsockeyeconformreasonablywelltothepublishedsummaries.althoughtheregressionequationsforincubationrateshaveallowedthemostdetailedpredictions.I-50PotentialsalmonenhancementaboveDevilCanyon.BecausetheSusitnaRiveranditstributariesupstreamofDevilCanyonarenaturallyinaccessibletosalmonmigrations(exceptforrareincursiontotributariesimmediatelyupstreamduringdroughtflowsinJune-August).thedesirabilityofinterventiontoenhancemigrationshasbeenexplored.TheAlaskaDepartmentofFishandGame'sFisheriesRehabilitation.Enhancement.andDevelopment(FRED)Divisionassessedfeasibilityandcostsofsuchenhancement.Althoughtheinternalreportshavenotbeenmadeavailable.theconclusionwasreachedthatupriverexpansionaboveDevilCanyonofanadromoussalmonpopulationswasnotpracticable.ReducedsummerflowswithWatanaDamoperatingcouldremovethebarrierofturbulentflowsinDevilCanyonandprovidepermenantaccessforadultsalmontoChinook.Cheechoko.Devil.Tsusena.andnumeroussmallercreeks.ThischangewouldopenawatershedareatotributarysalmonspawningthatwouldbeapproximatelyequalinsizetobothIndianRiverandPortageCreek.IncubationDuringtheJuly-Aprilperiod.salmoneggsareincubatingingravelsofsloughsandofsomesidechannels.Changesinriverflowandtemperatureduringthistimecanbeexpectedtohavesomeimpactonincubationsuccess.Theprincipalsourcesofimpactarephysicaldewateringandreducedintergravelwaterflowderivedfromthemainstem(whicharetreatedinAppendixH)andbiologicalchangesinincubationrateandemergencetimingcausedbyalteredtemperaturesandsmotheringofeggsbysilt(asdiscussedbelow).Redddewatering.OperationofWatanaDamhasbeenplannedtoavoidapower-peakingmodeofhydroelectricgenerationwhichwouldrequirefrequentchangesintheamountofwaterreleasedthroughturbinestothefree-flowingSusitnaRiver.Short-term.rapidfluctuationsindownstreamflowhavebeenofconcernatotherhydroelectricsites.especiallyforimpactsondevelopingsalmoneggs.embryos.andalevinsinrivergravels.Whensalmonspawnduringasustainedhighdischarge.subsequentreductionofflowmayexposespawningbedsanddewaterredds.TheFERCstaffhasreviewedfieldstudiesatseveralhydroelectricsitesintheU.S.whichhaveexaminedtheeffectsofdewateringredds(WittyandThompson1974;Stillwelletale1977;Bauersfield1978;Parametrixetale1979;McMullinandGraham1981)andexperimentalstudiesofdewateredartificialreddscontainingchinooksalmon.Thesestudieshaveidentifieddifferingvulnerabilitytodamageamongdevelopmentalstages(Beckeretale1982andunpublisheddata).BecausetheSustinaRiverisusedformainstemandsloughspawningbyallPacificsalmonspeciesexceptchinook.powerpeakingwouldhaveputspawningareasatrisk.Theproposedlimitationofreleasestotherivertothoseofabase-loadoperationconstitutesaneffectivefishconservationmeasurecomparedtoapeakingmodeofoperation.SomeredddewateringmayoccurinwinteraboveShermanduringreservoiroperations.There.normalicecoverisnotexpectedtoformduetowarmreservoirreleases.andpreprojecticedammingwillnotbeavailabletofloodcertainspawningsloughs.Theamountofsalmonproductionaffectedwillbesmall.amountingtofewerthan100spawningadults.Eggincubationratesatalteredtemperatures.ThelargestoragevolumeofWatanaReservoirwillcauseoutlettemperaturesduringoperationtobewarmerthannormal(preproject)inthefallandwinterincubationperiod.althoughthemeanannualrivertemperaturewithWatanaalonewillbeaboutthesameaspreproject.Developmentratesaretemperature-dependentandareimportantforsalmonbecauseprematureemergenceandearlyemigrationinducedbyabnormallywarmtemperatureshavebeenshowntoreducesurvivaltotheadultstage(Vernon1958;Taylor1980).whereasabnormallylowtemperaturescanpreventnormaldevelopment.Amajorfactorinreducedsurvivalofearlyemergingfryisbelievedtobetheirencounterwithcoldtemperatures.inadequateseasonalfooddevelopment.andhighpredationratesintheestuarineandmarineenvironments(Gilhousen1962).Earlier-emergingfrytendtobesmallerthanlater-emergingonesinlaboratorystudiesandfieldcollections(Graybilletale1979).whichmaymakethemmorevulnerabletomanysourcesofmortality.Thestaffhasevaluatedtheincubationperiodofsalmoneggsusingcumulative"temperatureunits"ordegree-daysfromtheliterature(whereadailytemperatureunitequals1°Cabovefreezingfora24-hperiod)andregressionequationspublishedbyWangaardandBurger(1983)forincubationrateversustemperatureforSusitnastocksofchumandsockeyesalmon.Althoughtemperatureunitcharacterizationisnotcompletelysatisfactory[see.forexample.objectionsbyBattle(1944)andMarr(1966).andevidenceofcompensatoryratechangesthattendtominimizeeffectsofalteredtemperaturesfoundbyGraybilletale(1979)].Ithasprovenusefulinhatcherymanagement(Piperetale1982).laboratoryinvestigations(e.g••Olsonetale1970).andimpactassessmentsofhydroelectricprojects(Graybilletale1979).Temperatureunitstohatchingandemergenceareavailableforeachsalmonspecies.basedlargelyonhatcheryexperiencesinOregon.Washington.andBritishColumbia(Table1.1-3).TheSusitnastocksofchumandsockeyeconformreasonablywelltothepublishedsummaries.althoughtheregressionequationsforincubationrateshaveallowedthemostdetailedpredictions. I-51Accurateestimatesofalteredthermalconditionsinsalmonreddsaredifficulttoobtainbecauseofthecomplex,site-specificinteractionsbetweensurfaceriverwater,mainsteminfiltration,andgroundwaterdischarge(Sec.4.1.3.2and4.1.3.3).Fishspawninareasofupwelling,althoughitisnotclearwhethertheattractantisintergravelwaterflow,thermaldifferences,orrelativepaucityofcementingsilt.Ingeneral,thermalpatternsofpotentialwatersourcesforincubationare:sloughsurfacetemperaturessimilarannuallytothemainstem32to55°F(O-l3°C);themainsteminfiltrationtemperaturecyclereducedinamplitude32to46°F(0-8°C)comparedtomainstemriverwaterwithatimelaggreaterinareasfurtherfromtheriverwatersource;anddeepgroundwaterupwellingwithatemperaturefairlyconstant[36to39°F(2-4°C)Jduetoslowmovementofinterstitialwaterandaveragingofsummerandwinterpercolationbythermalretentionofthegravel(Acres1983).Althoughfieldstudiesareunderwaytocharacterizeflowandthermalpatternsinareasusedforspawning,presentrelationshipsremainincompletelyunderstood(Trihey1982).Withalteredriverflow,therelativecontributionsofthethermallydifferentsourcestoaspawningareamaychange.(SeeSec.4.1.3.2forafurtherdiscussionofgroundwatertemperatures.)Consideringtheuncertaintiesinestimatingactualincubationtemperatures,thepreliminaryanalysishasfocusedonalteredmainstemrivertemperatures[aswasdonebyGraybilletal.(1979)Jandthepotentialshiftsinincubationratepatternsthattheywouldcause.Inaddition,weusedatypicalsloughtemperaturepatternasdescribedbyWangaardandBerger(1983).Asmorecompletedataonactualreddtemperaturesbecomeavailable,theanalysescanbeextended.ThemajorpotentialincubationimpactoftheSusitnaprojectisaccelerationofdevelopmentratesbywarmertemperaturesinautumnmonths(Figure1.2-1;Table1.2-2.Undergeneralrivertemperatureregimespredictedbytheapplicant,correctedforwarmingand/orcoolingasdischargestraversetheDevilCanyontoTalkeetnareach,early-spawningpinkandchumsalmon(mid-July)couldcompletedevelopmenttotheemergencestagebymid-tolateOctoberwithWatanaalone,ratherthanearlyspring.Laterpinkandchumspawningandevenearlyspawningofslower-developingsockeyeandcohoarelessaffectedandarepredictedtoemergemorenormallyinlatewintertospring.Theseprojectedeffectsreflectrapideggandembryodevelopmentthatwouldocurattheprolongedsummer-likeriver.temperaturesinSeptemberandearlyOctoberthataremaximumforearlyspawners.Thelong-termimpactstochumandpinksalmonpopulationscanonlybeestimatedwithadditionalstudiestodeterminemorerealistictemperaturesforspawninggravelsthroughouttheincubationseason.Intheworst-casescenarioinwhichthereislossofallchumandpinksalmonthatincubateinthesloughs,thetotalruntotheSusitnaRiverwouldbereducedbyanestimated11,840chumand3,550pinksalmon(seeExhibitE,Sec.2.3.2(b)[iiJ,SloughHabitat).Theimpactwouldbeconsiderablylessforlater-spawningfish.ChumsalmonspawnedonAugust15atmainstemtemperaturessuchasthosethatcouldoccurdownstreamofWatananearShermancouldcompleteyolkabsorptionbymid-MaycomparedtoanabnormallyprotractedearlyAugust.completionatpreprojectmainstemtemperatures(normalemergencefromsloughgravelsisinAprilaccordingtofielddata)(Figure1.2-2).Thisisstilldelayed,however,comparedtoincubationratesinthewarmerwatersofatypicalslough.Duringwinter,icethatformswhiletheriverisathigherthanhistoricflowscanbeexpectedtocausestagingthatwillovertopsidesloughsusedforsalmonspawning(mostlychumandsockeye).Thisovertoppingwoulddecreasetemperaturesinsloughgravelsinwhichsalmoneggsincubateandlengthenthetimerequiredforemergence.Thesignificanceforsalmonwoulddependonthetimeofyearwhenitoccurred.Overtoppingearlyinwinterwouldretarddevelopmenttothegreatestextent.Cessationofovertoppinginthespring,andreversiontogroundwatertemperatures,wouldalsoinfluenceemergencetiming.Figure1.2-2illustratestwoovertoppingscenarios;alateNovemberovertoppingcouldextendincubationintolateMayorJune.IfovertoppingceasesinMarchorAprilaswarmerreservoirsurfacewaterisreleasedfromprojectdams,thenthechangesinemergencetimingcouldbeinsignificant.Effectsofsiltonincubation.IncubationmortalityhasbeenidentifiedasthemostimportantfactorgoverningyearclassstrengthofpinksalmoninsoutheastAlaskastreams(McNeil1968)andofsockeyesalmoninCedarRiver,Washington(Stoberetal.1978),anditisundoubtedlyofmajorimportanceforallsalmon.Siltationistheprincipalnemesisofincubatingeggsinrivergravels,asseveralstudieshaveshownaninverserelationshipbetweentheamountofthesedimentinspawninggravelsandemergencesuccessofsalmonandtroutfry(Bjornn1969;Phillipsetal.1975;McCuddin1977;Tappel1981).WintersiltloadsfromoperatingtheSusitnareservoirshavethepotentialofreachinglevelsdetrimentaltodownstreamredds.Thepredampatternofhighturbiditiesinopenwaterseasonsandclarityduringfreeze-upwillbealteredbythelargestoragecapacitiesofthetworeservoirs(seeSec.4.1.3.2).Quantitativedataonembryosurvivalundervariouslevelsofwaterturbidityareavailablefromexperimentalresearchrelatedtomining(e.g.,ShawandMaga1943)andforestrypractices,buttheuncertaintiesofprojectalterationsduetotheSusitnaprojectmakequantitativeevaluationstenuous.AnalogieswithexistingglaciallakessuchasEklutnasuggestthatresidualturbidityfromoperationinwinterwillnotbedetrimental.There,theI-51Accurateestimatesofalteredthermalconditionsinsalmonreddsaredifficulttoobtainbecauseofthecomplex,site-specificinteractionsbetweensurfaceriverwater,mainsteminfiltration,andgroundwaterdischarge(Sec.4.1.3.2and4.1.3.3).Fishspawninareasofupwelling,althoughitisnotclearwhethertheattractantisintergravelwaterflow,thermaldifferences,orrelativepaucityofcementingsilt.Ingeneral,thermalpatternsofpotentialwatersourcesforincubationare:sloughsurfacetemperaturessimilarannuallytothemainstem32to55°F(O-l3°C);themainsteminfiltrationtemperaturecyclereducedinamplitude32to46°F(0-8°C)comparedtomainstemriverwaterwithatimelaggreaterinareasfurtherfromtheriverwatersource;anddeepgroundwaterupwellingwithatemperaturefairlyconstant[36to39°F(2-4°C)Jduetoslowmovementofinterstitialwaterandaveragingofsummerandwinterpercolationbythermalretentionofthegravel(Acres1983).Althoughfieldstudiesareunderwaytocharacterizeflowandthermalpatternsinareasusedforspawning,presentrelationshipsremainincompletelyunderstood(Trihey1982).Withalteredriverflow,therelativecontributionsofthethermallydifferentsourcestoaspawningareamaychange.(SeeSec.4.1.3.2forafurtherdiscussionofgroundwatertemperatures.)Consideringtheuncertaintiesinestimatingactualincubationtemperatures,thepreliminaryanalysishasfocusedonalteredmainstemrivertemperatures[aswasdonebyGraybilletal.(1979)Jandthepotentialshiftsinincubationratepatternsthattheywouldcause.Inaddition,weusedatypicalsloughtemperaturepatternasdescribedbyWangaardandBerger(1983).Asmorecompletedataonactualreddtemperaturesbecomeavailable,theanalysescanbeextended.ThemajorpotentialincubationimpactoftheSusitnaprojectisaccelerationofdevelopmentratesbywarmertemperaturesinautumnmonths(Figure1.2-1;Table1.2-2.Undergeneralrivertemperatureregimespredictedbytheapplicant,correctedforwarmingand/orcoolingasdischargestraversetheDevilCanyontoTalkeetnareach,early-spawningpinkandchumsalmon(mid-July)couldcompletedevelopmenttotheemergencestagebymid-tolateOctoberwithWatanaalone,ratherthanearlyspring.Laterpinkandchumspawningandevenearlyspawningofslower-developingsockeyeandcohoarelessaffectedandarepredictedtoemergemorenormallyinlatewintertospring.Theseprojectedeffectsreflectrapideggandembryodevelopmentthatwouldocurattheprolongedsummer-likeriver.temperaturesinSeptemberandearlyOctoberthataremaximumforearlyspawners.Thelong-termimpactstochumandpinksalmonpopulationscanonlybeestimatedwithadditionalstudiestodeterminemorerealistictemperaturesforspawninggravelsthroughouttheincubationseason.Intheworst-casescenarioinwhichthereislossofallchumandpinksalmonthatincubateinthesloughs,thetotalruntotheSusitnaRiverwouldbereducedbyanestimated11,840chumand3,550pinksalmon(seeExhibitE,Sec.2.3.2(b)[iiJ,SloughHabitat).Theimpactwouldbeconsiderablylessforlater-spawningfish.ChumsalmonspawnedonAugust15atmainstemtemperaturessuchasthosethatcouldoccurdownstreamofWatananearShermancouldcompleteyolkabsorptionbymid-MaycomparedtoanabnormallyprotractedearlyAugust.completionatpreprojectmainstemtemperatures(normalemergencefromsloughgravelsisinAprilaccordingtofielddata)(Figure1.2-2).Thisisstilldelayed,however,comparedtoincubationratesinthewarmerwatersofatypicalslough.Duringwinter,icethatformswhiletheriverisathigherthanhistoricflowscanbeexpectedtocausestagingthatwillovertopsidesloughsusedforsalmonspawning(mostlychumandsockeye).Thisovertoppingwoulddecreasetemperaturesinsloughgravelsinwhichsalmoneggsincubateandlengthenthetimerequiredforemergence.Thesignificanceforsalmonwoulddependonthetimeofyearwhenitoccurred.Overtoppingearlyinwinterwouldretarddevelopmenttothegreatestextent.Cessationofovertoppinginthespring,andreversiontogroundwatertemperatures,wouldalsoinfluenceemergencetiming.Figure1.2-2illustratestwoovertoppingscenarios;alateNovemberovertoppingcouldextendincubationintolateMayorJune.IfovertoppingceasesinMarchorAprilaswarmerreservoirsurfacewaterisreleasedfromprojectdams,thenthechangesinemergencetimingcouldbeinsignificant.Effectsofsiltonincubation.IncubationmortalityhasbeenidentifiedasthemostimportantfactorgoverningyearclassstrengthofpinksalmoninsoutheastAlaskastreams(McNeil1968)andofsockeyesalmoninCedarRiver,Washington(Stoberetal.1978),anditisundoubtedlyofmajorimportanceforallsalmon.Siltationistheprincipalnemesisofincubatingeggsinrivergravels,asseveralstudieshaveshownaninverserelationshipbetweentheamountofthesedimentinspawninggravelsandemergencesuccessofsalmonandtroutfry(Bjornn1969;Phillipsetal.1975;McCuddin1977;Tappel1981).WintersiltloadsfromoperatingtheSusitnareservoirshavethepotentialofreachinglevelsdetrimentaltodownstreamredds.Thepredampatternofhighturbiditiesinopenwaterseasonsandclarityduringfreeze-upwillbealteredbythelargestoragecapacitiesofthetworeservoirs(seeSec.4.1.3.2).Quantitativedataonembryosurvivalundervariouslevelsofwaterturbidityareavailablefromexperimentalresearchrelatedtomining(e.g.,ShawandMaga1943)andforestrypractices,buttheuncertaintiesofprojectalterationsduetotheSusitnaprojectmakequantitativeevaluationstenuous.AnalogieswithexistingglaciallakessuchasEklutnasuggestthatresidualturbidityfromoperationinwinterwillnotbedetrimental.There,the I-521020DEC1020NOVDATESOF00/EMERGENCEoRM116RM131_RM1491020OCTONLYoPINKSALMONoCHUMSALMON1020SEPTRM101-+---"\'\\\WATANAANDDEVILCANYON1020AUG1020JULFigure1.2-1.PredictedearlyemergenceofpinkandchumsalmonspawnedonJuly15atfourlocationsintheSusitnaRiverbetweenDevilCanyonoutlet(RM14a)andtheChulitnajunction(RM101).Watanaalone(lower)andWatanaandDevilCanyon(upper).24o10RM101RM1168RM131wRM1490:::::>6l-e:(0::Wa.4:EwI-2012108ffiNORMALSHERMAN>(noautumnemergence)0::6I-521020DEC1020NOVDATESOF00/EMERGENCEoRM116RM131_RM1491020OCTONLYoPINKSALMONoCHUMSALMON1020SEPTRM101-+---"\'\\\WATANAANDDEVILCANYON1020AUG1020JULFigure1.2-1.PredictedearlyemergenceofpinkandchumsalmonspawnedonJuly15atfourlocationsintheSusitnaRiverbetweenDevilCanyonoutlet(RM14a)andtheChulitnajunction(RM101).Watanaalone(lower)andWatanaandDevilCanyon(upper).24o10RM101RM1168RM131wRM1490:::::>6l-e:(0::Wa.4:EwI-2012108ffiNORMALSHERMAN>(noautumnemergence)0::6 Table 1.2-2.Dates Estimated for Emergence of Salmon Fry that Experience July-April Temperatures Projected for the Susitna River at Several Locations Between Devil Canyon and the Chulitna River Confluence.Temperatures were not Projected after April 30 1 .__..____.__.Iemperature Profi le~.t Watana On.=.l:LY+_ 1Temperat~..._e_i>r()fUest Watana and Devil Canyon+ Star·t.ing da.t(~ Pr'epro j ec t at Sherman RM 101 (Confluence)RM 116 RM 131 (Sher'man) RM 149 (Devil Canyon) Preproject at Sherman RM 101 (Confluence)RM 116 RM 131 (Sherman) RM 149 (Devil Canyon) ....._-___.--_----_._-_---. July 15 Pink C'~lum Sockt'ye (\uq.15 Pink C\H.l1l1 Sockeye Cuhu Sept.15 Chum Sockl)ye Cohu Oct.15 Cohu +1 =after 4/30. j( )f x ·x x· ·x x j( )f x 10/29 10/29 10/21 10/21 * )f )f x· x x 10/19 10/19 x * * x x * * 10/17 10/17 x x )f x )f x x· * * x * x· j( .)f x· x x 4/15 12/5 11/14 11/7 4/15 12/5 11/14 11/7 j(.*4/2 1/17 j(.*4/29 2/5 ...... I *4/29 215 U'l*W x·**x x·* * 4/30 x *·x * * * * j(. x·*·x * x *·x * Source:FERC staff;Temperature uni ts deri ved from Piper et al.(1982). Table 1.2-2.Dates Estimated for Emergence of Salmon Fry that Experience July-April Temperatures Projected for the Susitna River at Several Locations Between Devil Canyon and the Chulitna River Confluence.Temperatures were not Projected after April 30 1 .__..____.__.Iemperature Profi le~.,Watana On,,,,l.:/.y+_ 1 Temperature Profiles,Watana and Devil canyon+ Star·t.ing da.t(~ Preproject at Sherman RM 101 (Confluence)RM 116 RM 131 (Sher'man) RM 149 (Devil Canyon) Preproject at Sherman RM 101 (Confluence)RM 116 RM 131 (Sherman) RM 149 (Devil Canyon) ............_______._.__-_.__._------- July 15 Pink Sockt'ye (\uq.15 Pink C\H.l1l1 Sockeye Cuhu Sept.15 Chum Cohu Oct.15 Cohu +1 =after 4/30. ·x x· ·x 10/29 10/29 10/21 10/21 * x· x 10/19 10/19 * * x 1( 1( 10/17 10/17 x * * 1( x· .j( x 4/15 12/5 11/14 11/7 4/15 12/5 11/14 11/7 j(.*4/2 1/17 j(.*4/29 2/5 ...... I * * 4/29 215 U'lw x·**x x·* * 4/30 x *.j(1( * * 1(j(. x·1(.j(* x *.j(* Source:FERC staff;Temperature uni ts deri ved from Piper et al.(1982). Figure1.2-2.IncubationratesforchumsalmonspawnedonAugust15underdifferenttemperaturescenarios.(a)preprojectmainstematSherman,(b)ShermanmainstemwithWatanaDamalone,(c)ShermanmainstemwithWatanaandDevilCanyondams,(d)intergravelinapreprojectslough,(e)andsloughintergravelattwoovertoppingdates,NovemberandFebruary.Mainstemtemperaturesweredevelopedbythestafffromtheapplication.SloughtemperaturesandregressionequationsforincubationratemodelingwerethoseofWangaardandBerger(1983).~'/'• I~---JII,,I\,PREPROJECTSLOUGHCD',®",./././././",",'"~-~/-WATANA, ,",./MAINSTEM/J/",/'/~PREPROJECT...'/./MAINSTEM".///)./~f,#~WATANAANDD.C.MAINSTEMI-54~TEMPERATURES\\-PREPROJECTMAINSTEM--\·~WATANAMAINSTEM_-:\,,''i,,-WATANAANDD.C.MAINSTEM\ I "\ I\\\\\\\\\\'\\'\!...\"ASOND J F M A M J JMONTH810204060uoo100o2zo80I-0..et::oCf)CDe:::{~..Jo>-WI-W..J0..~ouWet::::)6l-e:::{et::W0..~4wI-Figure1.2-2.IncubationratesforchumsalmonspawnedonAugust15underdifferenttemperaturescenarios.(a)preprojectmainstematSherman,(b)ShermanmainstemwithWatanaDamalone,(c)ShermanmainstemwithWatanaandDevilCanyondams,(d)intergravelinapreprojectslough,(e)andsloughintergravelattwoovertoppingdates,NovemberandFebruary.Mainstemtemperaturesweredevelopedbythestafffromtheapplication.SloughtemperaturesandregressionequationsforincubationratemodelingwerethoseofWangaardandBerger(1983).~'/'• I~---JII,,I\,PREPROJECTSLOUGHCD',®",./././././",",'"~-~/-WATANA,,",./MAINSTEM/J/",/'/~PREPROJECT...'/./MAINSTEM".///)./~f,#~WATANAANDD.C.MAINSTEMI-54~TEMPERATURES\\-PREPROJECTMAINSTEM--\·~WATANAMAINSTEM_-:\,,''i,,-WATANAANDD.C.MAINSTEM\ I"\ I\\\\\\\\\\'\\'\!...\"ASOND J F M A M J JMONTH810204060uoo100o2zo80I-0..et::oCf)CDe:::{~..Jo>-WI-W..J0..~ouWet::::)6l-e:::{et::W0..~4wI- I-55CookInletAquacultureAssociationhasbuiltasalmonhatcheryatthepowertunneltailwater.Turbiditiesremainhigherthaninnormalstreamwaterinwinter,andsomedepositionoffinesiltonthechumandcohoeggsincubatedexperimentallyin1980and1981wasobserved,butemergencesuccesswashigh(98.4%in1982-83)evenforhatcherystandards(CIAA1983a,1983b).TheFERCstaffbelievesEklutnawillberepresentativeforturbidityretentionandwinterreleaseattheSusitnaproject.Therewouldbenegativeimpactsonincubatingsalmoneggsinsidechannelsandovertoppedsloughsifthereisheavyerosionofbanks,islands,andgravelbarsunderwinteroperationalconditionsofelevatedriverflowsandicestaging(Sec.4.1.3.2).Suchchannelreconfigurationmayoccuronlyinthefirstfewyearsofoperation.Thedegreeofimpactisspeculativeatpresent,butwouldlikelyamounttolocalizedlossesofreddproduction.Theimpactsonoverallpopulationsmaybeminor.JuvenileRearingGrowth-temperaturerelationships.Fishgrowthistemperature-dependent,andalterationofrivertemperaturesbelowtheSusitnaprojectdamswillcausesomechangeingrowthratesthatarephysiologicallypossible.Theexpectationofchangedgrowthisofparticularconcernforjuvenilesalmonofallfivespeciesthatdevelopintheriverforvaryinglengthsoftimepriortoandduringtheirseawardmigration.Itisknownthatlargerfishattimeofentrancetotheoceanhaveahigherlikelihoodofsurvivingtoadulthood(Foerster1954;Levanidov1964;Kanidyevetal.1970;Taylor1980).Thepossiblemagnitudeofchangeinpotentialgrowthrateofyoungsalmonhasbeencalculated(Figure1-2-3)fortemperaturepatternsprojectedbytheapplicantatdownstreamlocationsintheDevilCanyontoTalkeetnareach.Forpurposesofthisanalysis,severalassumptionsrelatingtobothtemperaturesandfishgrowthweremade.TemperaturepatternsbetweenMayandNovemberwerederivedfromfiguresintheapplicationforfourrepresentativelocationsspacedaboutequidistantintheSusitnaRiverbetweenDevilCanyonandtheconfluencewiththeChulitnaRiver:(1)RiverMile(RM)149justbelowthecanyon,RM131nearSherman,RM116nearLane,andRM101neartheconfluence.Considerationofseverallocationswasadvisablebecausewaterreleasedfromthedamswillwarmorcoolintransitdownriver,dependingonthetimeofyearandthedischargetemperature(afactorconsideredintemperatureprojectionsbytheapplicant).Becausetheapplicant'sthermalmodelswerenotrununiformlythroughtheentireopen-waterperiod,however,somejudgmentwasrequiredtogenerateatypicalpostprojectoperationalpatternforallfourstations.Similarly,variationsintemperaturecausedbyshort-termweatherpatternsweresmoothedfortheapplicant'spredictedtemperaturesandmeasuredvalues.Insomecases,theFERCstaffestimatedtemperaturechangesmarkedlydifferentfromthoseprojectedbytheapplicant;inthosecases,theresultingdifferencesingrowthpatternsareidentified.Forfishgrowth,therewereseveralassumptions:(1)anincreaseinweightcouldoccuronlyattemperaturesabove37.4°F(3°C),(2)allfivesalmonspecieswouldexhibitthewell-establishedpatternofweight-specificgrowthatdifferenttemperaturesdemonstratedforsockeyesalmon(Brett1974),(3)growthstartedat0.2g,and(4)allfishwouldfeedtosatiation(thusdemonstratinggrowthpotentialunderthevariousthermalregimesuncomplicatedbylimitedfoodsupply,whichwillbediscussedseparately).Foreachthermalpattern,Figure1.2-3showscumulativewetweightduringthegrowingseason,inamannerrecommendedbytheNationalAcademyofSciences/NationalAcademyofEngineering(1973)forevaluatinglong-termthermaleffectsonfishgrowth.TheresultsindicatelittlealterationofcurrentlyachievablegrowthundermainstemtemperatureswhenWatanaDamaloneisinplace.WithWatanaDamalone,retentionofwarmwaterintheriverinautumn(duetostorageinWatanaReservoir)generallycompensatesforsomewhatdelayed(butsimilar)summerpeaktemperaturesindeterminingthecumulativeannualgrowthofthosespeciesthatremainallyear(chinook,coho).Ifchum,pink,andsockeyesalmoncontinuetomigrateoutofthisreachofriverbytheendofJuly,theirgrowthcould,however,bereducedbynearly30%.CalculationswerealsomadefortheTalkeetnatomouthreach,whereitisreasonabletoconcludethattherewillbereductioningrowthofsimilarorlessermagnitude.ThermalmodelingbyFERCstaffhasquestionedwhetherwarmerwaterswillpersistintheriverintheautumn(Sec.4.1.3.2);iftemperaturesdonotremainwarm,thenannualgrowthforchinookandcohosalmonwouldbereduced.Whereasthesecalculationshaveusedweight-specificgrowthdataforsockeyesalmon(becausetheyaremostcomplete),hatcherymanagershavelongrealizedthattherearequantitativedifferencesinthewaytemperaturecontrolsgrowthofeachspecies(Burrows1963).Forexample,sockeyegrowfasterbetween40°F(4.4°C)and60°F(15.6°C)thanchinook,althoughthegrowthratesofchinookacceleratemorerapidlywithtemperatureincreasesinthisrange.Forevery10degreeriseinthisrange,foodconsumptionincreases45%insockeyeand60%inchinook.Alteredtemperatures,andthusgrowthrates,intheSusitnafollowingdamconstructionwouldlikelyfavorthespeciesmostcapableofgrowingbestincoolerwater(whichappeartobesockeyeandpinksalmon).I-55CookInletAquacultureAssociationhasbuiltasalmonhatcheryatthepowertunneltailwater.Turbiditiesremainhigherthaninnormalstreamwaterinwinter,andsomedepositionoffinesiltonthechumandcohoeggsincubatedexperimentallyin1980and1981wasobserved,butemergencesuccesswashigh(98.4%in1982-83)evenforhatcherystandards(CIAA1983a,1983b).TheFERCstaffbelievesEklutnawillberepresentativeforturbidityretentionandwinterreleaseattheSusitnaproject.Therewouldbenegativeimpactsonincubatingsalmoneggsinsidechannelsandovertoppedsloughsifthereisheavyerosionofbanks,islands,andgravelbarsunderwinteroperationalconditionsofelevatedriverflowsandicestaging(Sec.4.1.3.2).Suchchannelreconfigurationmayoccuronlyinthefirstfewyearsofoperation.Thedegreeofimpactisspeculativeatpresent,butwouldlikelyamounttolocalizedlossesofreddproduction.Theimpactsonoverallpopulationsmaybeminor.JuvenileRearingGrowth-temperaturerelationships.Fishgrowthistemperature-dependent,andalterationofrivertemperaturesbelowtheSusitnaprojectdamswillcausesomechangeingrowthratesthatarephysiologicallypossible.Theexpectationofchangedgrowthisofparticularconcernforjuvenilesalmonofallfivespeciesthatdevelopintheriverforvaryinglengthsoftimepriortoandduringtheirseawardmigration.Itisknownthatlargerfishattimeofentrancetotheoceanhaveahigherlikelihoodofsurvivingtoadulthood(Foerster1954;Levanidov1964;Kanidyevetal.1970;Taylor1980).Thepossiblemagnitudeofchangeinpotentialgrowthrateofyoungsalmonhasbeencalculated(Figure1-2-3)fortemperaturepatternsprojectedbytheapplicantatdownstreamlocationsintheDevilCanyontoTalkeetnareach.Forpurposesofthisanalysis,severalassumptionsrelatingtobothtemperaturesandfishgrowthweremade.TemperaturepatternsbetweenMayandNovemberwerederivedfromfiguresintheapplicationforfourrepresentativelocationsspacedaboutequidistantintheSusitnaRiverbetweenDevilCanyonandtheconfluencewiththeChulitnaRiver:(1)RiverMile(RM)149justbelowthecanyon,RM131nearSherman,RM116nearLane,andRM101neartheconfluence.Considerationofseverallocationswasadvisablebecausewaterreleasedfromthedamswillwarmorcoolintransitdownriver,dependingonthetimeofyearandthedischargetemperature(afactorconsideredintemperatureprojectionsbytheapplicant).Becausetheapplicant'sthermalmodelswerenotrununiformlythroughtheentireopen-waterperiod,however,somejudgmentwasrequiredtogenerateatypicalpostprojectoperationalpatternforallfourstations.Similarly,variationsintemperaturecausedbyshort-termweatherpatternsweresmoothedfortheapplicant'spredictedtemperaturesandmeasuredvalues.Insomecases,theFERCstaffestimatedtemperaturechangesmarkedlydifferentfromthoseprojectedbytheapplicant;inthosecases,theresultingdifferencesingrowthpatternsareidentified.Forfishgrowth,therewereseveralassumptions:(1)anincreaseinweightcouldoccuronlyattemperaturesabove37.4°F(3°C),(2)allfivesalmonspecieswouldexhibitthewell-establishedpatternofweight-specificgrowthatdifferenttemperaturesdemonstratedforsockeyesalmon(Brett1974),(3)growthstartedat0.2g,and(4)allfishwouldfeedtosatiation(thusdemonstratinggrowthpotentialunderthevariousthermalregimesuncomplicatedbylimitedfoodsupply,whichwillbediscussedseparately).Foreachthermalpattern,Figure1.2-3showscumulativewetweightduringthegrowingseason,inamannerrecommendedbytheNationalAcademyofSciences/NationalAcademyofEngineering(1973)forevaluatinglong-termthermaleffectsonfishgrowth.TheresultsindicatelittlealterationofcurrentlyachievablegrowthundermainstemtemperatureswhenWatanaDamaloneisinplace.WithWatanaDamalone,retentionofwarmwaterintheriverinautumn(duetostorageinWatanaReservoir)generallycompensatesforsomewhatdelayed(butsimilar)summerpeaktemperaturesindeterminingthecumulativeannualgrowthofthosespeciesthatremainallyear(chinook,coho).Ifchum,pink,andsockeyesalmoncontinuetomigrateoutofthisreachofriverbytheendofJuly,theirgrowthcould,however,bereducedbynearly30%.CalculationswerealsomadefortheTalkeetnatomouthreach,whereitisreasonabletoconcludethattherewillbereductioningrowthofsimilarorlessermagnitude.ThermalmodelingbyFERCstaffhasquestionedwhetherwarmerwaterswillpersistintheriverintheautumn(Sec.4.1.3.2);iftemperaturesdonotremainwarm,thenannualgrowthforchinookandcohosalmonwouldbereduced.Whereasthesecalculationshaveusedweight-specificgrowthdataforsockeyesalmon(becausetheyaremostcomplete),hatcherymanagershavelongrealizedthattherearequantitativedifferencesinthewaytemperaturecontrolsgrowthofeachspecies(Burrows1963).Forexample,sockeyegrowfasterbetween40°F(4.4°C)and60°F(15.6°C)thanchinook,althoughthegrowthratesofchinookacceleratemorerapidlywithtemperatureincreasesinthisrange.Forevery10degreeriseinthisrange,foodconsumptionincreases45%insockeyeand60%inchinook.Alteredtemperatures,andthusgrowthrates,intheSusitnafollowingdamconstructionwouldlikelyfavorthespeciesmostcapableofgrowingbestincoolerwater(whichappeartobesockeyeandpinksalmon). 16(0)614512U04-;'~10IX:.....:::>:r:.....e>~83wIX:~LlJQ.2:6LlJ.....242006(b)WATANAANDDEVILCANYONDAMS14TEMPERATURESBEFORE(SHERMAN=RM131)5AfTt12_104<.>!,C7'LlJIX:83~:::>~e>WIX:~LlJ6Q.22:LlJ.....42003015311530153115311530153115MAYJUNEJULYAUGSEPTOCTDECI-56Figure1.2-3.TemperatureandcumulativegrowthforrepresentativejuvenilesalmonintheSusitnaRiverbetweenDevilCanyonandTalkeetna,beforeand-aftertheproject.16(0)614512U04-;'~10IX:.....:::>:r:.....e>~83wIX:~LlJQ.2:6LlJ.....242006(b)WATANAANDDEVILCANYONDAMS14TEMPERATURESBEFORE(SHERMAN=RM131)5AfTt12_104<.>!,C7'LlJIX:83~:::>~e>WIX:~LlJ6Q.22:LlJ.....42003015311530153115311530153115MAYJUNEJULYAUGSEPTOCTDECI-56Figure1.2-3.TemperatureandcumulativegrowthforrepresentativejuvenilesalmonintheSusitnaRiverbetweenDevilCanyonandTalkeetna,beforeand-aftertheproject. I-57Foodavailability.MajorconsequencesofimpoundingtheSusitnaRiverwillbereductioninsummertimeturbidityandstabilizationofflows,changesthatcouldsignificantlyincreasebenthicproductivityandthusfoodavailabilityforfishfauna(seeSec.4.1.3.2andAppendixI,Sec.B.2.1.2).Changesinfishpopulationsbelowdamshavebeendocumentedinanumberofinstances(e.g.,SpenceandHynes1971b;WardandStanford1979)andincludechangesinfaunalcomposition,diversity,andabundance.However,specificallylinkingchangesininvertebratepopulationswithchangesinfishpopulationshasprovendifficult(SpenceandHynes1971a).EvidencethatchangesinfishpopulationscouldoccurintheSusitnacomesfromstudiesofothersubarctichydroelectricdevelopments.FollowingreductioninglacialturbidityintheRiverSkjoma,Norway,therewasanincreasedproductionofalgae,increaseddensityandgrowthrateofpresmoltAtlanticsalmon(Salmosalar),andamorerapidcommencementofseawardemigrationbytheolderfry(Heggberget~ress).Partofthiseffectmay,however,havebeenduetosimultaneousincrease[4to7°F(2-3°C)]insummertemperature.Huntsman(1948)alsoobservedthatincreasedgrowthofalgaeleadstoincreaseddensityofpresmoltstreamdwellingsalmoninCanada.DecreasedsummerflowsinNorwegianstreamsduetohydroelectricdevelopmentalsocausedincreaseddensitiesofbottominvertebrates(Koksvik1977).IntheUnitedStates,Graybilletal.(1979)demonstratedthatadecreaseinwater-levelfluctuationsbelowadamontheSkagitRiver,Washington,ledtobetterbenthicproduction,betterutilizationofaquaticinsectsbysalmonfry,feweremptystomachs,andbettergrowth.Zooplanktonoriginatinginanupstreamreservoircanbeanimportantsupplementtofoodresourcesfordownstreamsalmonids,andmaybecomeimportantinthepostimpoundmentSusitna.IntheSkagitRiver,Washington,reservoir-derivedcopepodsandcladoceranswereimportantconstituentsofChinookandcohosalmonstomachcontents,becomingthedominantfooditeminApril(Graybilletal.1979).ReducedturbiditycoulddirectlyaffectfishfeedingbyincreasingtheefficiencyofsightfeedersasshowninexperimentsbyNoggle(1978),althoughthiseffectcouldbedetrimentaltosmallchumandpinksalmonthatcouldbefeduponbyolderchinookandcohoorresidentfishessuchasrainbowtroutandDollyVarden.ThedegreetowhichincreasedfishfoodavailabilityperunitareaintheSusitnaduringprojectoperationwilloffsettheeffectsofadecreaseinwettedperimeterandreducedwatertemperaturesisamatterofspeculationwithoutquantitativestudiesofthepresentconditionandmorethoroughpredictionsaboutchanges.BecausethermalchangeswithWatanaalonearerelativelysmall,itislikelythatoverallproductivityoftheSusitnafromthedamtoTalkeetnawillriseandjuvenilesalmonproductionshouldincrease.Undoubtedly,reductioninturbidityandflowstabilizationofferimportantmanagementopportunitiesforSusitnaRiversalmon.Debrisdamsandjuvenilesalmonhabitat.Woodydebris(trees,stumps,logs,brush)inthepresentSusitnacreatessmallpoolsandbackwaterareasatcertainlocationsusedbyyoungsalmonforrestingandfeeding.Blockageofupstreamsourcesofthisdebrisandreductionsinpeakflowsthaterodewoodedriverbankscouldleadtodepletionofsuchdebrisintheriverbyprogressivewashoutdownstream,andthusdegradationofrearinghabitat.TheimportanceofwoodydebrisinsalmonidnurserystreamshasbeenreviewedrecentlybyBryant(1983).Heconcludedthatunlessthereisclearblockageofeitherupstreamordownstreammigration,debrisdammingwithinastreamchannelbenefitsrearinghabitatandthedebrisshouldbeleftinplace.QuantitativedataarenotavailableforeitherthesignificanceofdebrisforsustainingsalmonhabitatintheSusitnaorthequantitiesinthevariousreachesbelowthedamsitesthatarederivedfromsourcesabovethem.Aspeculativeappraisalsuggeststhatsufficientdebrisisavailablefromtributaries(e.g.,PortageCreek,IndianRiver)andwoodedriverbankstoprovideadequatejuvenilehabitat.NoeffectsshouldbediscernablebelowTalkeetnawheretheChulitnaandTalkeetnariversareheavilyladenwithwoodydebris.Winterecologyofyoungsalmonids.Elevationofwintertemperaturesinthereachesdownstreamofthedamswillbeaprojectmodificationthatmayaffectthebehaviorandsurvivalofoverwinteringfishes.Thetemperaturealterationwillbemostpronouncedclosetoadamoutletanditwillbemoderateddownstreambylowairtemperaturesandcoldtributaryinflows(seeSec.4.1.3.2).ThewinterecologyofyoungsalmonidshasbeenthesubjectofintensivestudyoutsideofAlaska,andtheresultsofferindicationsofwhatcouldhappenintheSusitnawhenWatanaDamisinoperation.Thespeciesthatoverwinterinfreshwaterasfrytypicallychangefromactivefeedingandterritorialdefensetohidingincoverorindeepwaterasthetemperaturedropsbelowabout41°F(5°C).(Hartman1965;ChapmanandBjornn1969;BustardandNarver1975a,b).If41°F(SOC)thresholdforinducingbehavioralchangesisgermanetoSusitnapopulations(currentlyuntested),theneventhemostelevatedtemperaturesinwinterwillstillbebelowit,andanormalannualbehaviorcyclewilloccur.Thepronouncedlaginautumnalcoolingprojectedbytheapplicant,however,willdelayonsetofinactivity.WhencomparedtopreprojectSusitnaRivertemperaturesatSherman,thedelayofonsetof41°F(5°C)wouldbeI-57Foodavailability.MajorconsequencesofimpoundingtheSusitnaRiverwillbereductioninsummertimeturbidityandstabilizationofflows,changesthatcouldsignificantlyincreasebenthicproductivityandthusfoodavailabilityforfishfauna(seeSec.4.1.3.2andAppendixI,Sec.B.2.1.2).Changesinfishpopulationsbelowdamshavebeendocumentedinanumberofinstances(e.g.,SpenceandHynes1971b;WardandStanford1979)andincludechangesinfaunalcomposition,diversity,andabundance.However,specificallylinkingchangesininvertebratepopulationswithchangesinfishpopulationshasprovendifficult(SpenceandHynes1971a).EvidencethatchangesinfishpopulationscouldoccurintheSusitnacomesfromstudiesofothersubarctichydroelectricdevelopments.FollowingreductioninglacialturbidityintheRiverSkjoma,Norway,therewasanincreasedproductionofalgae,increaseddensityandgrowthrateofpresmoltAtlanticsalmon(Salmosalar),andamorerapidcommencementofseawardemigrationbytheolderfry(Heggberget~ress).Partofthiseffectmay,however,havebeenduetosimultaneousincrease[4to7°F(2-3°C)]insummertemperature.Huntsman(1948)alsoobservedthatincreasedgrowthofalgaeleadstoincreaseddensityofpresmoltstreamdwellingsalmoninCanada.DecreasedsummerflowsinNorwegianstreamsduetohydroelectricdevelopmentalsocausedincreaseddensitiesofbottominvertebrates(Koksvik1977).IntheUnitedStates,Graybilletal.(1979)demonstratedthatadecreaseinwater-levelfluctuationsbelowadamontheSkagitRiver,Washington,ledtobetterbenthicproduction,betterutilizationofaquaticinsectsbysalmonfry,feweremptystomaChs,andbettergrowth.Zooplanktonoriginatinginanupstreamreservoircanbeanimportantsupplementtofoodresourcesfordownstreamsalmonids,andmaybecomeimportantinthepostimpoundmentSusitna.IntheSkagitRiver,Washington,reservoir-derivedcopepodsandcladoceranswereimportantconstituentsofChinookandcohosalmonstomachcontents,becomingthedominantfooditeminApril(Graybilletal.1979).ReducedturbiditycoulddirectlyaffectfishfeedingbyincreasingtheefficiencyofsightfeedersasshowninexperimentsbyNoggle(1978),althoughthiseffectcouldbedetrimentaltosmallchumandpinksalmonthatcouldbefeduponbyolderchinookandcohoorresidentfishessuchasrainbowtroutandDollyVarden.ThedegreetowhichincreasedfishfoodavailabilityperunitareaintheSusitnaduringprojectoperationwilloffsettheeffectsofadecreaseinwettedperimeterandreducedwatertemperaturesisamatterofspeculationwithoutquantitativestudiesofthepresentconditionandmorethoroughpredictionsaboutchanges.BecausethermalchangeswithWatanaalonearerelativelysmall,itislikelythatoverallproductivityoftheSusitnafromthedamtoTalkeetnawillriseandjuvenilesalmonproductionshouldincrease.Undoubtedly,reductioninturbidityandflowstabilizationofferimportantmanagementopportunitiesforSusitnaRiversalmon.Debrisdamsandjuvenilesalmonhabitat.Woodydebris(trees,stumps,logs,brush)inthepresentSusitnacreatessmallpoolsandbackwaterareasatcertainlocationsusedbyyoungsalmonforrestingandfeeding.Blockageofupstreamsourcesofthisdebrisandreductionsinpeakflowsthaterodewoodedriverbankscouldleadtodepletionofsuchdebrisintheriverbyprogressivewashoutdownstream,andthusdegradationofrearinghabitat.TheimportanceofwoodydebrisinsalmonidnurserystreamshasbeenreviewedrecentlybyBryant(1983).Heconcludedthatunlessthereisclearblockageofeitherupstreamordownstreammigration,debrisdammingwithinastreamchannelbenefitsrearinghabitatandthedebrisshouldbeleftinplace.QuantitativedataarenotavailableforeitherthesignificanceofdebrisforsustainingsalmonhabitatintheSusitnaorthequantitiesinthevariousreachesbelowthedamsitesthatarederivedfromsourcesabovethem.Aspeculativeappraisalsuggeststhatsufficientdebrisisavailablefromtributaries(e.g.,PortageCreek,IndianRiver)andwoodedriverbankstoprovideadequatejuvenilehabitat.NoeffectsshouldbediscernablebelowTalkeetnawheretheChulitnaandTalkeetnariversareheavilyladenwithwoodydebris.Winterecologyofyoungsalmonids.Elevationofwintertemperaturesinthereachesdownstreamofthedamswillbeaprojectmodificationthatmayaffectthebehaviorandsurvivalofoverwinteringfishes.Thetemperaturealterationwillbemostpronouncedclosetoadamoutletanditwillbemoderateddownstreambylowairtemperaturesandcoldtributaryinflows(seeSec.4.1.3.2).ThewinterecologyofyoungsalmonidshasbeenthesubjectofintensivestudyoutsideofAlaska,andtheresultsofferindicationsofwhatcouldhappenintheSusitnawhenWatanaDamisinoperation.Thespeciesthatoverwinterinfreshwaterasfrytypicallychangefromactivefeedingandterritorialdefensetohidingincoverorindeepwaterasthetemperaturedropsbelowabout41°F(5°C).(Hartman1965;ChapmanandBjornn1969;BustardandNarver1975a,b).If41°F(SOC)thresholdforinducingbehavioralchangesisgermanetoSusitnapopulations(currentlyuntested),theneventhemostelevatedtemperaturesinwinterwillstillbebelowit,andanormalannualbehaviorcyclewilloccur.Thepronouncedlaginautumnalcoolingprojectedbytheapplicant,however,willdelayonsetofinactivity.WhencomparedtopreprojectSusitnaRivertemperaturesatSherman,thedelayofonsetof41°F(5°C)wouldbe I-58about10to20d(dependingondistancedownstream)withWatanaDamalone(Figure1.2-3).Thesignificanceofsuchdelaysisunclear,butitcouldbepositive(throughprolongedtimeforfeedingandgrowth)ornegative(throughaddedtimeforpredation).IfthebalanceoffoodintakeandenergyrequirementsofmaintenancemetabolismduringwinterhidingiscrucialtooverwinteringsurvivalofyoungsalmonintheSusitna,asitisforsomeotherfishspecieselsewhere(Shutereta1.1980),thenanincreasedperiodoffeedingactivityandgrowthwouldbeadefiniteadvantage.Frystrandingbyfluctuatingflows.Acommonproblembelowhydroelectricdamsismortalityofjuvenilesa1monidsbystrandingwhenflowsarereduceddiurnally(Thompson1970;Phinney1974;Bauersfe1d1978).Factorsinfluencingthemagnitudeofsuchmortalitiesarebiological(e.g.,theseasonalabundanceofeachspeciesinshallowwaterareas),physical(thetopographyandsubstratecompositionofthechannel),andoperational(magnitude,timeofday,andrateofflowfluctuation).Fieldstudies(e.g.,Graybilleta1.1979)haveindicatedthatshoreline-feedingspecies,particularlychinooksalmon,areespeci11yvulnerable,whereaspinkandchum(whichemigraterapidlyinthemainchannel)arelessaffected.TheSusitnaprojectascurrentlyconceivedwillnotintroducepeakingpowerwaterfluctuationstotheriverbelowDevilCanyon;therewillinsteadbestabilizationofnaturallyoccurringfreshetflowsinsummer.Anymortalitiescurrentlycausedbystrandingfollowingfreshetsshouldbereduced.SalmonEmigrationTemperatureandspringmigrationofsalmonsmo1ts.GenerallywarmerwintertemperaturesintheSusitnaRiverbelowWatanaDammaymeananearlierbreakupofriverice,warmerrivertemperaturesearlierintheseason,andpotentialadvancementofthetimingofsmo1tout-migration.Becausethetimingandvariabilityofnormalrivertemperatures,icebreak-up,andbeginningofsmo1temigrationarestillpoorlycharacterizedfortheSusitna,estimationofimpactsisspeculativeandbasedonwhathasbeenobservedelsewhere.Thebreak-upoficecoverinthespringisprobablyanimportanttimingcuefortheinitiationofsomemigrations.Icemayblockmigrationpriortobreak-up,andtherewouldbeaphysiologicaladvantagetomovingtofeedingareasassoonaspossibleinthespring.Mostresearchshowingcorrelationsofout-migrationwithicebreak-uphasinvolvedsockeyesalmon(Burgner1962a,b;Brannon1972;Hartmaneta1.1967;Foerster1937;Groot1965).Short-termelevationsoftemperaturestimulatepulsesofmigrationandcooltemperaturesdecreasemigration(Hartmaneta1.1967).Thattemperaturerisecanstimulateout-migrationhasbeenconfirmedwithbehavioralexperiments.Chumfry,cohofryandsmo1ts,andsockeyesmo1tsallswitchfrompositiverheotaxis(orientationupstream)tonegativerheotaxisinresponsetosuddenincreasesintemperaturewhentestedinsmallcirculartanks(Hoar1951;Keen1eysideandHoar1955).However,temperatureisobviouslynottheonlyfactortimingthemigration.Cohosmo1tmigrationseemstobeinitiatedbylunarcontrolofthyroxinelevels(Graueta1.1981).Similarmechanismsmayoccurasbackuptimingsystemsinallsalmonspecies.Itseemsreasonabletoconcludethatadvancementofrivertemperaturesinspringmayhaveaconcomitantadvancementinout-migrationofjuvenilesa1monids.ThisadvancementcouldbedetrimentalforthepopulationsinvolvedifnegativeeffectsofearlyentrancetocoldcoastalwatersseenbyGi1housen(1962)andTaylor(1980)holdforSusitnaRiverstocks.SalmonPopulation-LevelEffectsShiftsinrelativeabundanceamongsalmonspecies.Potentialshiftsmayoccurinrelativeabundanceofthefivesalmonspeciesduetodifferentdirectionsordegreesofresponsetodam-inducedenvironmental changes.SuchshiftscouldbeimportantforfisheriesinboththeriverandinCookInletandmightbeavoidedifdeemeddisadvantageous.Thefivespecieshavepartitionedtheaquaticenvironmentininnumerablewayssothatallfivecoexist.Somepartitioningisobvious,suchaschinookutilizingtributariesforspawningexclusively,whereassockeyeandchumfrequentlyspawninsloughs.Pinkandchummakearapidsmo1temigrationinspringandsummer,whilecoho,chinook,andprobablysockeye(fromTalkeetnatothemouth)remainintheriverforoneormoreyears.Moresubtledifferencesamongspeciesexistaswell,suchasingrowthresponsestotemperaturelevels,infoodresourcesused,ortypesofcoverselected.Asthenumerousfeaturesoftheenvironmentfluctuatefromyeartoyear,therelativeadvantageforonespeciesshiftstoanother,backandforth,withageneralcyclic,"dynamicdis-equilibrium"ofrelativepopulationsizesbeingestablishedthatischaracteristicoftheriversystem.Hutchinson(1953,1961)theorizedaboutsuchdynamicinfluencesthatkeptcloselyinteractingspeciesfromexcludingoneortheotherthroughcompetition.Subsequentexperimentationhasshownthatrandomenvironmentalfluctuationscouldmaintaindiversityinstreamcommunities(Patrick1975)andincommunitiesI-58about10to20d(dependingondistancedownstream)withWatanaDamalone(Figure1.2-3).Thesignificanceofsuchdelaysisunclear,butitcouldbepositive(throughprolongedtimeforfeedingandgrowth)ornegative(throughaddedtimeforpredation).IfthebalanceoffoodintakeandenergyrequirementsofmaintenancemetabolismduringwinterhidingiscrucialtooverwinteringsurvivalofyoungsalmonintheSusitna,asitisforsomeotherfishspecieselsewhere(Shutereta1.1980),thenanincreasedperiodoffeedingactivityandgrowthwouldbeadefiniteadvantage.Frystrandingbyfluctuatingflows.Acommonproblembelowhydroelectricdamsismortalityofjuvenilesa1monidsbystrandingwhenflowsarereduceddiurnally(Thompson1970;Phinney1974;Bauersfe1d1978).Factorsinfluencingthemagnitudeofsuchmortalitiesarebiological(e.g.,theseasonalabundanceofeachspeciesinshallowwaterareas),physical(thetopographyandsubstratecompositionofthechannel),andoperational(magnitude,timeofday,andrateofflowfluctuation).Fieldstudies(e.g.,Graybilleta1.1979)haveindicatedthatshoreline-feedingspecies,particularlychinooksalmon,areespeci11yvulnerable,whereaspinkandchum(whichemigraterapidlyinthemainchannel)arelessaffected.TheSusitnaprojectascurrentlyconceivedwillnotintroducepeakingpowerwaterfluctuationstotheriverbelowDevilCanyon;therewillinsteadbestabilizationofnaturallyoccurringfreshetflowsinsummer.Anymortalitiescurrentlycausedbystrandingfollowingfreshetsshouldbereduced.SalmonEmigrationTemperatureandspringmigrationofsalmonsmo1ts.GenerallywarmerwintertemperaturesintheSusitnaRiverbelowWatanaDammaymeananearlierbreakupofriverice,warmerrivertemperaturesearlierintheseason,andpotentialadvancementofthetimingofsmo1tout-migration.Becausethetimingandvariabilityofnormalrivertemperatures,icebreak-up,andbeginningofsmo1temigrationarestillpoorlycharacterizedfortheSusitna,estimationofimpactsisspeculativeandbasedonwhathasbeenobservedelsewhere.Thebreak-upoficecoverinthespringisprobablyanimportanttimingcuefortheinitiationofsomemigrations.Icemayblockmigrationpriortobreak-up,andtherewouldbeaphysiologicaladvantagetomovingtofeedingareasassoonaspossibleinthespring.Mostresearchshowingcorrelationsofout-migrationwithicebreak-uphasinvolvedsockeyesalmon(Burgner1962a,b;Brannon1972;Hartmaneta1.1967;Foerster1937;Groot1965).Short-termelevationsoftemperaturestimulatepulsesofmigrationandcooltemperaturesdecreasemigration(Hartmaneta1.1967).Thattemperaturerisecanstimulateout-migrationhasbeenconfirmedwithbehavioralexperiments.Chumfry,cohofryandsmo1ts,andsockeyesmo1tsallswitchfrompositiverheotaxis(orientationupstream)tonegativerheotaxisinresponsetosuddenincreasesintemperaturewhentestedinsmallcirculartanks(Hoar1951;Keen1eysideandHoar1955).However,temperatureisobviouslynottheonlyfactortimingthemigration.Cohosmo1tmigrationseemstobeinitiatedbylunarcontrolofthyroxinelevels(Graueta1.1981).Similarmechanismsmayoccurasbackuptimingsystemsinallsalmonspecies.Itseemsreasonabletoconcludethatadvancementofrivertemperaturesinspringmayhaveaconcomitantadvancementinout-migrationofjuvenilesa1monids.ThisadvancementcouldbedetrimentalforthepopulationsinvolvedifnegativeeffectsofearlyentrancetocoldcoastalwatersseenbyGi1housen(1962)andTaylor(1980)holdforSusitnaRiverstocks.SalmonPopulation-LevelEffectsShiftsinrelativeabundanceamongsalmonspecies.Potentialshiftsmayoccurinrelativeabundanceofthefivesalmonspeciesduetodifferentdirectionsordegreesofresponsetodam-inducedenvironmental changes.SuchshiftscouldbeimportantforfisheriesinboththeriverandinCookInletandmightbeavoidedifdeemeddisadvantageous.Thefivespecieshavepartitionedtheaquaticenvironmentininnumerablewayssothatallfivecoexist.Somepartitioningisobvious,suchaschinookutilizingtributariesforspawningexclusively,whereassockeyeandchumfrequentlyspawninsloughs.Pinkandchummakearapidsmo1temigrationinspringandsummer,whilecoho,chinook,andprobablysockeye(fromTalkeetnatothemouth)remainintheriverforoneormoreyears.Moresubtledifferencesamongspeciesexistaswell,suchasingrowthresponsestotemperaturelevels,infoodresourcesused,ortypesofcoverselected.Asthenumerousfeaturesoftheenvironmentfluctuatefromyeartoyear,therelativeadvantageforonespeciesshiftstoanother,backandforth,withageneralcyclic,"dynamicdis-equilibrium"ofrelativepopulationsizesbeingestablishedthatischaracteristicoftheriversystem.Hutchinson(1953,1961)theorizedaboutsuchdynamicinfluencesthatkeptcloselyinteractingspeciesfromexcludingoneortheotherthroughcompetition.Subsequentexperimentationhasshownthatrandomenvironmentalfluctuationscouldmaintaindiversityinstreamcommunities(Patrick1975)andincommunities I-59oflakeplankton(reviewedbyHutchinson1975).Differencesintemperature-dependentgrowthratesandtheireffectsonrelativesurvivaloftwocloselyrelatedwarm-waterfisheshavebeenreported(CoutantandDeAngelis1983).Differencesineffectsamongsalmonspeciesaresufficientlyclearforsomesourcesofchangetoprojectchangesinrelativeabundance(seeprevioussection).Otherarenotwellenoughquantifiedtogivemuchguidanceregardingrelativeadvantages/disadvantagesoftheenvironmentalchangestobeinducedbytheSusitnaproject.Somethatarequantified,suchasdifferenceingrowthratesatdifferenttemperatures,maynotbequantitativelygermanetoSusitnastocks.ItisapparentthatenvironmentalpartitioningissomewhatdifferentinmajorwaysintheSusitnathanelsewhere.Forexample,chinookintheSusitnaaretributaryspawners,whereasinothersystems(e.g.,theCu1umbiaRiver)theyutilizemainstemsites.MoresubtlecharacteristicsoftheSusitnaspeciesbalancenodoubtdifferfromthoseofotherareasaswell.Currently,itappearsthatstocksofchumandsockeyesalmoncouldbethemostseverelyimpactedbyoperation,duetopotentiallossofspawninginsloughs.Pinkmaybeseverelyimpactedbyreservoirfillingandfailtorecoverduetotheshortlifecycle.Astheprojectimpactstoenvironmentalfeaturesbecomebetterdefinedandquantified,andasthefishpopulationsarebetterunderstood,clearerprojectionsaboutrelativeadvantagesmaybemade.Thestateofbasicknowledgeandecologicaltheoryrelatedtocompetitiveprocessesmakesmostpredictionsspeculativeatthispoint.SeeSec.1.2.2,SummaryofEnvironmentalImpactsonSalmonPopulations,foradiscussionoftheexpectedlong-termtrendsinsalmonpopulationsandeffectsofchangesinabundanceofsalmonstocksonfisheries.ThisdiscussionincludesconsiderationoftheconstructionphaseandoperationphaseofWatanadevelopmentandDevilCanyondevelopmenttogether.WatanaReservoirFishFaunaAlargenumberofstudieshavedocumentedcharacteristicchangesinfishfaunaofriverswhentheyaredammedforhydroe1ecteicpurposes.Migratoryspecies(eitheranadromousorhavingextensiveriverinemovements)generallydisappear,pelagicspeciesincreasedramaticallyiftheyarepresentinthewatershed(usuallyinsmalllakesthatareflooded),andcertainlittoralzonepredatorygamefishsuchaspikeexpand.HabitatpotentialforfishinWatanaReservoirislimitedbycoldtemperatures,lowproductivity,highsiltloadsinsummermonths,andlargedrawdownthatwillpreventdevelopmentofalittoralzone(Sec.4.1.3.2).StudiesinScandanavia(e.g.,GrimasandNilsson1965)provideusefulanalogieswithwhatcanbeexpectedinWatanaandDevilCanyonreservoirs.GraylinghaveeffectivelycolonizednewScandanavianreservoirsespeciallyneartributarymouthswheretheydependheavilyonterrestrialinsectsforfood.Char(Arcticchar,Sa1ve1inusalpinus,foundinScandinavia,towhichtheDollyVardeniscloselyalliedandmaybethesamespecies;Krueger1981b)differentiatedrapidlyinScandinavianlakesintodiscretepopulationsthatexploitdifferentfoodsources,includingbenthicinvertebratesandpelagiczooplankton(ISACF1980).ResidentDollyVardenintributariesintheimpoundmentreachshouldfindthereservoirtobeanexcellentwinteringlake,comparabletolakesgenerallyutilizedelsewhereinitsrange(Krueger1981b).WhitefishhaveremainedimportantinsomeScandanavianreservoirsbuthavedeclinedinothers,particularlyasthereservoirshaveaged.Burbothaveremained.Thespeciesthatregularlyformeddenserpopulationswereroachandperch(pelagicspeciesforwhichtherearenocurrentanalogsintheupperSusitna)andnorthernpike.Introducedspecies,lakeandrainbowtrout,whicharealreadypresentintheSusitna,havebecomeimportantinEuropeanalpinelakesandreservoirs.TheapplicantevaluatedtheannualdrawdowncycleofWatanaReservoirinrelationtofishspawning.Winterdewateringandspringflooding(Sec.4.1.3.1)arebothofconcernforsuccessfulreproductioninthereservoir.Graylingwillspawninflowingwateroftributariesduringthelow-waterperiodofMayandJune,andembryosbelowaboutelevation2133ft(646M)willbeinundatedbeforehatchingandlikelykilled.Humpbackwhitefishandburbotspawninthereservoirgenerallyatdepthslessthan20ft(6M)inOctober-December.Reservoirdrawdowninwinterwilldewaterembryos.Laketroutalsospawninthereservoir,butatdepthsof3to110ft(0.9to33m)inSeptember-October;later,deeperspawningareaswillsurvivewinterdrawdown.DollyVardeneggs.whicharelaidintributariesinthefall,willnotbeaffectedbythedrawdowncycle.Rainbowtrout,notevaluatedbytheapplicant.willlikelyberestrictedinamannersimilartograyling.Inadditiontoyear-aroundresidentfishes,WatanaReservoirisexpectedtoprovideimportantnewoverwinteringhabitatforfishesthatoccupytributariesandtheSusitnaupstreamoftheOshetnaRiver.Kokanee(landlockedsockeyesalmon)isthemostabundantfishinmanylargesUbalpinelakesandreservoirsofwesternNorthAmerica,anditcouldprovideavaluablesa1monidfishspeciesforDevilCanyonandWatanareservoirsandtributariesaboveDevilCanyon.~ThefishareI-59oflakeplankton(reviewedbyHutchinson1975).Differencesintemperature-dependentgrowthratesandtheireffectsonrelativesurvivaloftwocloselyrelatedwarm-waterfisheshavebeenreported(CoutantandDeAngelis1983).Differencesineffectsamongsalmonspeciesaresufficientlyclearforsomesourcesofchangetoprojectchangesinrelativeabundance(seeprevioussection).Otherarenotwellenoughquantifiedtogivemuchguidanceregardingrelativeadvantages/disadvantagesoftheenvironmentalchangestobeinducedbytheSusitnaproject.Somethatarequantified,suchasdifferenceingrowthratesatdifferenttemperatures,maynotbequantitativelygermanetoSusitnastocks.ItisapparentthatenvironmentalpartitioningissomewhatdifferentinmajorwaysintheSusitnathanelsewhere.Forexample,chinookintheSusitnaaretributaryspawners,whereasinothersystems(e.g.,theCu1umbiaRiver)theyutilizemainstemsites.MoresubtlecharacteristicsoftheSusitnaspeciesbalancenodoubtdifferfromthoseofotherareasaswell.Currently,itappearsthatstocksofchumandsockeyesalmoncouldbethemostseverelyimpactedbyoperation,duetopotentiallossofspawninginsloughs.Pinkmaybeseverelyimpactedbyreservoirfillingandfailtorecoverduetotheshortlifecycle.Astheprojectimpactstoenvironmentalfeaturesbecomebetterdefinedandquantified,andasthefishpopulationsarebetterunderstood,clearerprojectionsaboutrelativeadvantagesmaybemade.Thestateofbasicknowledgeandecologicaltheoryrelatedtocompetitiveprocessesmakesmostpredictionsspeculativeatthispoint.SeeSec.1.2.2,SummaryofEnvironmentalImpactsonSalmonPopulations,foradiscussionoftheexpectedlong-termtrendsinsalmonpopulationsandeffectsofchangesinabundanceofsalmonstocksonfisheries.ThisdiscussionincludesconsiderationoftheconstructionphaseandoperationphaseofWatanadevelopmentandDevilCanyondevelopmenttogether.WatanaReservoirFishFaunaAlargenumberofstudieshavedocumentedcharacteristicchangesinfishfaunaofriverswhentheyaredammedforhydroe1ecteicpurposes.Migratoryspecies(eitheranadromousorhavingextensiveriverinemovements)generallydisappear,pelagicspeciesincreasedramaticallyiftheyarepresentinthewatershed(usuallyinsmalllakesthatareflooded),andcertainlittoralzonepredatorygamefishsuchaspikeexpand.HabitatpotentialforfishinWatanaReservoirislimitedbycoldtemperatures,lowproductivity,highsiltloadsinsummermonths,andlargedrawdownthatwillpreventdevelopmentofalittoralzone(Sec.4.1.3.2).StudiesinScandanavia(e.g.,GrimasandNilsson1965)provideusefulanalogieswithwhatcanbeexpectedinWatanaandDevilCanyonreservoirs.GraylinghaveeffectivelycolonizednewScandanavianreservoirsespeciallyneartributarymouthswheretheydependheavilyonterrestrialinsectsforfood.Char(Arcticchar,Sa1ve1inusalpinus,foundinScandinavia,towhichtheDollyVardeniscloselyalliedandmaybethesamespecies;Krueger1981b)differentiatedrapidlyinScandinavianlakesintodiscretepopulationsthatexploitdifferentfoodsources,includingbenthicinvertebratesandpelagiczooplankton(ISACF1980).ResidentDollyVardenintributariesintheimpoundmentreachshouldfindthereservoirtobeanexcellentwinteringlake,comparabletolakesgenerallyutilizedelsewhereinitsrange(Krueger1981b).WhitefishhaveremainedimportantinsomeScandanavianreservoirsbuthavedeclinedinothers,particularlyasthereservoirshaveaged.Burbothaveremained.Thespeciesthatregularlyformeddenserpopulationswereroachandperch(pelagicspeciesforwhichtherearenocurrentanalogsintheupperSusitna)andnorthernpike.Introducedspecies,lakeandrainbowtrout,whicharealreadypresentintheSusitna,havebecomeimportantinEuropeanalpinelakesandreservoirs.TheapplicantevaluatedtheannualdrawdowncycleofWatanaReservoirinrelationtofishspawning.Winterdewateringandspringflooding(Sec.4.1.3.1)arebothofconcernforsuccessfulreproductioninthereservoir.Graylingwillspawninflowingwateroftributariesduringthelow-waterperiodofMayandJune,andembryosbelowaboutelevation2133ft(646M)willbeinundatedbeforehatchingandlikelykilled.Humpbackwhitefishandburbotspawninthereservoirgenerallyatdepthslessthan20ft(6M)inOctober-December.Reservoirdrawdowninwinterwilldewaterembryos.Laketroutalsospawninthereservoir,butatdepthsof3to110ft(0.9to33m)inSeptember-October;later,deeperspawningareaswillsurvivewinterdrawdown.DollyVardeneggs.whicharelaidintributariesinthefall,willnotbeaffectedbythedrawdowncycle.Rainbowtrout,notevaluatedbytheapplicant.willlikelyberestrictedinamannersimilartograyling.Inadditiontoyear-aroundresidentfishes,WatanaReservoirisexpectedtoprovideimportantnewoverwinteringhabitatforfishesthatoccupytributariesandtheSusitnaupstreamoftheOshetnaRiver.Kokanee(landlockedsockeyesalmon)isthemostabundantfishinmanylargesUbalpinelakesandreservoirsofwesternNorthAmerica,anditcouldprovideavaluablesa1monidfishspeciesforDevilCanyonandWatanareservoirsandtributariesaboveDevilCanyon.~Thefishare 1-60primarilylake-dwellersandspawninautumn,bothalonglakeshoresandintributarystreams.ThelargeKokaneearevaluablesportfish,andthejuvenilesarethemajorpelagicpreyspeciesforotherlargesportfishsuchasKanloopsrainbowandlaketrout(Northcote1972;FraleyandGraham1982;SportFishingInstitute1983).TheKokaneearelargelypelagicplanktonfeeders,utilizingcladoceranzooplanktersBosminaandDaphnia.AttemptstosupplementtheiravailableplanktonicfoodinseverallakesthroughintroductionofMysisrelicta,alargeplanktoniccrustacean,metwithnegativeresultsastheMysisitselfdepletedBosminaandDaphniapopulationsonwhichsmallKokaneedepend(Morganet~978).ThisexperienceparalleledthatobservedinScandinavianlakesinwhichMysiswasintroduced(HansonandLindstrom1979).EstablishmentandmaintenanceofaKokaneepopulationinWatanaReservoircouldprovideapelagiccomponentofthefaunacomparabletotheScandinavianroachandaviablealternativetoADF&GFREDDivisionproposalstoopentheupperSusitnatoanadromoussalmonstocksthroughfishpassagefacilitiesatDevilCanyon.LimitingfactorswouldbethecapabilityoftheturbidWatanaReservoirtosustainzooplanktonandimpairedreproductionalongthereservoirshoveline(althoughtheupperSusitnaandtributariesshouldprovideabundantspawninghabitat).1.2.2.DevilCanyonDevelopment1.2.2.1.PlantCommunitiesBecausetheturbidSustinaRiverwillhavebeenclarifiedanditsflowregulatedbyWatanaDam,siltadditionsduringDevilCanyonconstructioncanbeexpectedtohavesomeimpactintheDevilCanyontoTalkeetnareachthroughscouringandshadingofperiphytonalgaeonsubmergedrocks.Theeffectsshouldbeofshortdurationandoflittlelastingsignificancefortheriverineecosystem.ThereshouldbenodetectablechangesbelowtheconfluencewiththeturbidChulitnaRiver.ReservoirfillingwillinundateriverinealgalcommunitiesbelowWatanaandreplacethemwithplanktonicalgaederivedmostlyfromWatanaReservoir.DownstreamofDevilCanyonDam,fillingshouldhavenonoticeableimpactonbenthicalgaebeyondsmallchangesinwettedsurfaceareathatarewithinnormalrivervariability.DevilCanyonoperationshouldhaveonlyasmallincrementalimpactontheSusitnaRiverdownstream,comparedtoriverineconditionswhenWatanaDamoperatesalone.Reducedsummertemperatures(comparedtobothpreprojectandWatanaaloneconditions)canbeexpectedtosomewhatreduceproductivityofbenthicalage,butproductionshouldstillexceedpre-Watanalevelsduetolowturbidity.Ashortreachbetweendamandpowerhousewillbedewatered(about1000m)andremovedfromproduction.NodetectablechangesinaquaticplantcommunitiesareexpectedbelowtheconfluenceoftheChulitnaRiverwhenDevilCanyonDamcommencesoperation,duetotheoverwhelmingeffectsofturbidityintheunregulatedChulitnaandTalkeetnariversandthechangesinturbidityandflowintheSusitnaalreadycausedbyWatanaDam.TheshortresidencetimeforwaterinDevilCanyonReservoir(Sec.4.1.3.1)nearlyensuresthatthephytoplanktoncommunitywillbecomposedofpopulationsderivedlargelyfromWatanaReservoir,althoughadditionaldevelopmentcanoccurintheincreasinglyclearDevilCanyonReservoirwater.Diatomspeciesareexpectedtodominate.StratifiedflowsfromWatanaoutlettotheDevilCanyonoutletmaylengthenretentiontimesforsomeisolatedwatermassesandallowpopulationsindependentofWatanacontributionstodevelopseasonally.1.2.2.2.InvertebrateCommunitiesSiltfromDevilCanyonconstructionwilltemporarilyaffectbenthicinvertebratesintheriverforseveralmilesdownstreamofthesite,butitisunlikelythattheywouldbereducedtopre-Watanalowlevels.ReservoirfillingwillrapidlyremoveriverinebenthosinthereservoirreachandreplaceitwithalessproductiveplanktonicinvertebratecommunityderivedfromWatanaReservoir.Nodetectableimpactfromfillingisanticipatedoninvertebratesbelowthelocalzoneatthedam.WithsedimentloadsalreadyreducedandflowsstabilizedintheSusitnaRiverbyWatanaDam,additionofDevilCanyonDamwillprincipallyaffecttimingandratesofdevelopmentofinvertebratesduetoreducedsummertemperaturesandincreasedwintertemperatures.OverallbenthicinvertebrateproductivityinthisreachislikelytobesignificantlylowerthanthatwithWatanaDamalone,butstillmuchhigherthanbeforetheproject.Additionaltimeforplanktondevelopmentinthereservoirshouldfurtherstimulatefilter-feedingbenthosintheSusitnadownstreamofthedam.LackoficescourinthereachbetweenDevilCanyonandShermanwillprotectandenhancepopulationsthere.Improvementsinwaterclarityandflowstability,andreductionintemperaturesintheSusitnaRiverabovetheChulitnaconfluence,areexpectedtobemaskedbytheinfluencesof1-60primarilylake-dwellersandspawninautumn,bothalonglakeshoresandintributarystreams.ThelargeKokaneearevaluablesportfish,andthejuvenilesarethemajorpelagicpreyspeciesforotherlargesportfishsuchasKanloopsrainbowandlaketrout(Northcote1972;FraleyandGraham1982;SportFishingInstitute1983).TheKokaneearelargelypelagicplanktonfeeders,utilizingcladoceranzooplanktersBosminaandDaphnia.AttemptstosupplementtheiravailableplanktonicfoodinseverallakesthroughintroductionofMysisrelicta,alargeplanktoniccrustacean,metwithnegativeresultsastheMysisitselfdepletedBosminaandDaphniapopulationsonwhichsmallKokaneedepend(Morganet~978).ThisexperienceparalleledthatobservedinScandinavianlakesinwhichMysiswasintroduced(HansonandLindstrom1979).EstablishmentandmaintenanceofaKokaneepopulationinWatanaReservoircouldprovideapelagiccomponentofthefaunacomparabletotheScandinavianroachandaviablealternativetoADF&GFREDDivisionproposalstoopentheupperSusitnatoanadromoussalmonstocksthroughfishpassagefacilitiesatDevilCanyon.LimitingfactorswouldbethecapabilityoftheturbidWatanaReservoirtosustainzooplanktonandimpairedreproductionalongthereservoirshoveline(althoughtheupperSusitnaandtributariesshouldprovideabundantspawninghabitat).1.2.2.DevilCanyonDevelopment1.2.2.1.PlantCommunitiesBecausetheturbidSustinaRiverwillhavebeenclarifiedanditsflowregulatedbyWatanaDam,siltadditionsduringDevilCanyonconstructioncanbeexpectedtohavesomeimpactintheDevilCanyontoTalkeetnareachthroughscouringandshadingofperiphytonalgaeonsubmergedrocks.Theeffectsshouldbeofshortdurationandoflittlelastingsignificancefortheriverineecosystem.ThereshouldbenodetectablechangesbelowtheconfluencewiththeturbidChulitnaRiver.ReservoirfillingwillinundateriverinealgalcommunitiesbelowWatanaandreplacethemwithplanktonicalgaederivedmostlyfromWatanaReservoir.DownstreamofDevilCanyonDam,fillingshouldhavenonoticeableimpactonbenthicalgaebeyondsmallchangesinwettedsurfaceareathatarewithinnormalrivervariability.DevilCanyonoperationshouldhaveonlyasmallincrementalimpactontheSusitnaRiverdownstream,comparedtoriverineconditionswhenWatanaDamoperatesalone.Reducedsummertemperatures(comparedtobothpreprojectandWatanaaloneconditions)canbeexpectedtosomewhatreduceproductivityofbenthicalage,butproductionshouldstillexceedpre-Watanalevelsduetolowturbidity.Ashortreachbetweendamandpowerhousewillbedewatered(about1000m)andremovedfromproduction.NodetectablechangesinaquaticplantcommunitiesareexpectedbelowtheconfluenceoftheChulitnaRiverwhenDevilCanyonDamcommencesoperation,duetotheoverwhelmingeffectsofturbidityintheunregulatedChulitnaandTalkeetnariversandthechangesinturbidityandflowintheSusitnaalreadycausedbyWatanaDam.TheshortresidencetimeforwaterinDevilCanyonReservoir(Sec.4.1.3.1)nearlyensuresthatthephytoplanktoncommunitywillbecomposedofpopulationsderivedlargelyfromWatanaReservoir,althoughadditionaldevelopmentcanoccurintheincreasinglyclearDevilCanyonReservoirwater.Diatomspeciesareexpectedtodominate.StratifiedflowsfromWatanaoutlettotheDevilCanyonoutletmaylengthenretentiontimesforsomeisolatedwatermassesandallowpopulationsindependentofWatanacontributionstodevelopseasonally.1.2.2.2.InvertebrateCommunitiesSiltfromDevilCanyonconstructionwilltemporarilyaffectbenthicinvertebratesintheriverforseveralmilesdownstreamofthesite,butitisunlikelythattheywouldbereducedtopre-Watanalowlevels.ReservoirfillingwillrapidlyremoveriverinebenthosinthereservoirreachandreplaceitwithalessproductiveplanktonicinvertebratecommunityderivedfromWatanaReservoir.Nodetectableimpactfromfillingisanticipatedoninvertebratesbelowthelocalzoneatthedam.WithsedimentloadsalreadyreducedandflowsstabilizedintheSusitnaRiverbyWatanaDam,additionofDevilCanyonDamwillprincipallyaffecttimingandratesofdevelopmentofinvertebratesduetoreducedsummertemperaturesandincreasedwintertemperatures.OverallbenthicinvertebrateproductivityinthisreachislikelytobesignificantlylowerthanthatwithWatanaDamalone,butstillmuchhigherthanbeforetheproject.Additionaltimeforplanktondevelopmentinthereservoirshouldfurtherstimulatefilter-feedingbenthosintheSusitnadownstreamofthedam.LackoficescourinthereachbetweenDevilCanyonandShermanwillprotectandenhancepopulationsthere.Improvementsinwaterclarityandflowstability,andreductionintemperaturesintheSusitnaRiverabovetheChulitnaconfluence,areexpectedtobemaskedbytheinfluencesof 1-61theotherriversthatwillcontinuetosuppresspotentialbenthicinvertebratedevelopment.Becausebenthicpopulationsarelow.increasedturbidityinwinterisnotexpectedtocausenoticeableimpacts.ZooplanktonwithinDevilCanyonReservoirisexpectedtobedominatedbyadditionsfromWatana.Furtherreductionsinturbidityandisolationofsomewatermassesduringperiodsofstratifiedflowcouldallowzooplanktonincreases.1.2.2.3FishCommunities1.2.2.3.1ConstructionPhaseAsatWatanaDam.constructionwillpreemptashortreachofriverbottomfishhabitatforthedamitself[about1100ft(3540m)betweencofferdams);introducesilttotheriverduringseveralconstructionperiodsincludingplacementofcotterdams.dredgingforconstructionmaterials.andclearingofthereservoirarea;andconvertcreekandriverinehabitattoreservoirhabitatintheimpoundedreach.ResidentandanadromousfishesareexpectedtobeimpactedmorestronglybysedimentadditionfromDevilCanyonconstructionthanwasthecaseforWatanabecauseoffishcommunityadaptationtothemoresilt-freeconditionsafterWatanafilling.Anydetectablesedimentimpactisexpectedtobesmallandofshortduration.however.FillingDevilCanyonreservoirwillinundateabout32mi(53km)ofmainstemSusitnahabitatand11mi(18km)oftributaryhabitats.Theriverinespeciescommunitywillshifttoalacustrineassemblage(seeSec.1.2.2.3.2.whiletheapplicantestimatesthatlossofclear-watertributaryhabitatinTsusenandFogcreekswilleliminateabout1200graylinglongerthan8in(20cm).TemperatureestimateswerenotavailablefortheSusitnadownstreamoftheprojectduringthetwo-stagefillingprocess(Sec.4.1.3.2.Assumingasummerfillingperiod(tocoincidewithmaximuminflowtoWatanaReservoir).andconsideringtheeffectsofDevilCanyonoperationontemperaturesoftheriverdownstream(see1.2.2.3.2).onecanassumeamarkeddecreaseinsummerrivertemperatureduringfillingandimpactstofishsimilartothoseduringoperation.DevilCanyonReservoirwillbefilledinamatterofthreemonths.Thefillingofthisreservoirisnotexpectedtoresultinanyadditionalimpactsonspawninghabitatorspawningsuccess.DegradationandlossofspawninghabitatbelowDevilCanyonDamduringconstructionofthedamitselfduetoincreasedturbidityandsiltationwillbeminimalandlocalizedtothefirstseveralmilesbelowthedamsite.ThereisessentiallynosuitablespawninghabitatimmediatelydownriverfromtheDevilCanyonDamsite(RM152.0)untilPortageCreekatRM149.1.2.2.3.2OperationPhaseOperationofDevilCanyonandWatanadamstogetherwillhavesomeadditionalnegativeimpactonsalmonintheSusitnaRiverdownstreamoftheprojectfromthatofWatanaDamalone.Thisisduelargelytothealteredtemperatureregime.whichwillbemarkedlycoolerinsummerwithbothdamsoperatingandsomewhatwarmerinwinter.PostprojectstreamflowsundertheoperationofWatanaandDevilCanyondamswouldbesimilartothoseunderoperationofWatanaDamalone.MostoftheimpactsrelatedtohabitatavailabilitywouldalreadyhaveoccurredunderthestartupandoperationofWatanaDam.Therewillbeanadditionallossofapproximately1.5mi(2.5km)ofriverhabitatbetweenthedamandthepowerhouseoutlet.ofwhichabout3300ft(1000m)maybedryandtheremainderconvertedtobackwater.SalmonSpawningHabitatThemostsignificantdownstreamenvironmentalimpactresultingfromtheoperationofDevilCanyonDammaybethechangeinwinterwatertemperatureregime.whichmay.basedontheapplicant'smodeling.causetheicefronttoformbetweenTalkeetna(RM99)andSherman(RM130).insteadofbetweenSherman(RM130)andPortageCreek(RM149)aswithWatanaalone.Theriverstageintheopen-waterreachwillbelowerthanthestagepresentunderanicecover.Thus.somemainstem.slough.andside-channelhabitatusedforspawningduringtheperiodJunethroughSeptemberwillbedewateredduringthewinter.potentiallyresultinginthefreezingofeggsincubatinginthesedewateredhabitats.Thisimpactwillbesomewhatameliorated.however.sincesalmontendtoselectzonesofgroundwaterupwellingwhichwillnotfreeze.ThedependenceofgroundwaterupwellingonriverstageisdiscussedinSec.4.1.3.2.WithWatanaandDevilCanyonbothoperating.summerflowsareonlyslightlylowerthanwithWatanaalone(Sec.4.1.1.4.1).andthusaccessproblemsforadultsalmonenteringsloughspawninghabitatsandreductionsinareaofsuitablespawninghabitatwithinthesloughsare1-61theotherriversthatwillcontinuetosuppresspotentialbenthicinvertebratedevelopment.Becausebenthicpopulationsarelow.increasedturbidityinwinterisnotexpectedtocausenoticeableimpacts.ZooplanktonwithinDevilCanyonReservoirisexpectedtobedominatedbyadditionsfromWatana.Furtherreductionsinturbidityandisolationofsomewatermassesduringperiodsofstratifiedflowcouldallowzooplanktonincreases.1.2.2.3FishCommunities1.2.2.3.1ConstructionPhaseAsatWatanaDam.constructionwillpreemptashortreachofriverbottomfishhabitatforthedamitself[about1100ft(3540m)betweencofferdams);introducesilttotheriverduringseveralconstructionperiodsincludingplacementofcotterdams.dredgingforconstructionmaterials.andclearingofthereservoirarea;andconvertcreekandriverinehabitattoreservoirhabitatintheimpoundedreach.ResidentandanadromousfishesareexpectedtobeimpactedmorestronglybysedimentadditionfromDevilCanyonconstructionthanwasthecaseforWatanabecauseoffishcommunityadaptationtothemoresilt-freeconditionsafterWatanafilling.Anydetectablesedimentimpactisexpectedtobesmallandofshortduration.however.FillingDevilCanyonreservoirwillinundateabout32mi(53km)ofmainstemSusitnahabitatand11mi(18km)oftributaryhabitats.Theriverinespeciescommunitywillshifttoalacustrineassemblage(seeSec.1.2.2.3.2.whiletheapplicantestimatesthatlossofclear-watertributaryhabitatinTsusenandFogcreekswilleliminateabout1200graylinglongerthan8in(20cm).TemperatureestimateswerenotavailablefortheSusitnadownstreamoftheprojectduringthetwo-stagefillingprocess(Sec.4.1.3.2.Assumingasummerfillingperiod(tocoincidewithmaximuminflowtoWatanaReservoir).andconsideringtheeffectsofDevilCanyonoperationontemperaturesoftheriverdownstream(see1.2.2.3.2).onecanassumeamarkeddecreaseinsummerrivertemperatureduringfillingandimpactstofishsimilartothoseduringoperation.DevilCanyonReservoirwillbefilledinamatterofthreemonths.Thefillingofthisreservoirisnotexpectedtoresultinanyadditionalimpactsonspawninghabitatorspawningsuccess.DegradationandlossofspawninghabitatbelowDevilCanyonDamduringconstructionofthedamitselfduetoincreasedturbidityandsiltationwillbeminimalandlocalizedtothefirstseveralmilesbelowthedamsite.ThereisessentiallynosuitablespawninghabitatimmediatelydownriverfromtheDevilCanyonDamsite(RM152.0)untilPortageCreekatRM149.1.2.2.3.2OperationPhaseOperationofDevilCanyonandWatanadamstogetherwillhavesomeadditionalnegativeimpactonsalmonintheSusitnaRiverdownstreamoftheprojectfromthatofWatanaDamalone.Thisisduelargelytothealteredtemperatureregime.whichwillbemarkedlycoolerinsummerwithbothdamsoperatingandsomewhatwarmerinwinter.PostprojectstreamflowsundertheoperationofWatanaandDevilCanyondamswouldbesimilartothoseunderoperationofWatanaDamalone.MostoftheimpactsrelatedtohabitatavailabilitywouldalreadyhaveoccurredunderthestartupandoperationofWatanaDam.Therewillbeanadditionallossofapproximately1.5mi(2.5km)ofriverhabitatbetweenthedamandthepowerhouseoutlet.ofwhichabout3300ft(1000m)maybedryandtheremainderconvertedtobackwater.SalmonSpawningHabitatThemostsignificantdownstreamenvironmentalimpactresultingfromtheoperationofDevilCanyonDammaybethechangeinwinterwatertemperatureregime.whichmay.basedontheapplicant'smodeling.causetheicefronttoformbetweenTalkeetna(RM99)andSherman(RM130).insteadofbetweenSherman(RM130)andPortageCreek(RM149)aswithWatanaalone.Theriverstageintheopen-waterreachwillbelowerthanthestagepresentunderanicecover.Thus.somemainstem.slough.andside-channelhabitatusedforspawningduringtheperiodJunethroughSeptemberwillbedewateredduringthewinter.potentiallyresultinginthefreezingofeggsincubatinginthesedewateredhabitats.Thisimpactwillbesomewhatameliorated.however.sincesalmontendtoselectzonesofgroundwaterupwellingwhichwillnotfreeze.ThedependenceofgroundwaterupwellingonriverstageisdiscussedinSec.4.1.3.2.WithWatanaandDevilCanyonbothoperating.summerflowsareonlyslightlylowerthanwithWatanaalone(Sec.4.1.1.4.1).andthusaccessproblemsforadultsalmonenteringsloughspawninghabitatsandreductionsinareaofsuitablespawninghabitatwithinthesloughsare 1-62onlyslightlygreaterthanwithWatanaalone.AnalysesbyFERCstaffindicatethatforninesloughsaboveTalkeetnathefrequencyofoccurrenceofacuteaccesslimitationswillbe67%inJuly.54%inAugust.and55%inSeptember.Theseanalysesalsoindicateareductioninwettedsurfaceareainninesloughsof55%inJuly."39%inAugust.and0%inSeptember(Sec.4.1.1.4.2).GasSupersaturationWithoutconevalves.DevilCanyonDamisprojected(Sec.4.1.3.2)tocreatesupersaturatedconditionsdownstreaminexcessofthe110%lethallimitformostaquaticlife(NAS/NAE1973)forover70%oftheyearswhensummerflowofhydropowerturbinesisaugmentedwithdischargewater.Conevalvesshouldreduceoreliminatethesehighlevels.Withoutconevalvesproposedbytheapplicant.orasimilarmitigativemeasure.highmortalitiesareexpecteddownstreamoftheproject.TheseconditionscouldpersisttotheChulitnaconfluenceandhavesevereconsequencesforthefisheryamountingtonearlycompletelossoffisheryresources.Withconevalves.theseshouldbeinsignificantmortality.EggIncubationRatesatAlteredTemperaturesThethermaleffectsoneggincubationestimatedforWatanaReservoiralone(Sec.I.2.1.3.2)willbesomewhatreducedwithbothdamsinoperationinspiteofadditionalprolongationofwarmtemperaturesintothelateautumnbyDevilCanyonDam.Early-spawningpinkandchumsalmoncouldproduceemergingfryinNovember-Decemberwithbothdamsinoperation(Figure1.2-1.TableI.2-2).LaterspawningfishwouldbemoreaffectedthanwithWatanaalone(FigureI.2-2).Forlatespawners.theprojectedwintermainstemtemperaturesmorecloselyapproximatepreprojectsloughtemperatures.whichmayaidsuccess.especiallyformainstemorside-channelredds.Growth-TemperatureRelationshipsforJuvenileRearingPotentialgrowthofjuvenilesalmondownstreamofDevilCanyonandWatanadamsshowsmarkeddecreaseswhenbothareinoperation(Figure1.2-3.TableI.2-1).Summerpeaktemperaturesarereducedtowellbelowtheoptimalgrowthtemperatureofsalmon(near59°For15°C).andtheprolongedreleaseofabnormallywarmwaterinautumndoesnotcompensateforlostgrowth.Annualgrowthcouldpotentiallyreachonlyabout50%ofpreprojectlevels.Speciesthatemigrateinmidsummercouldaccumulateonlyaboutone-thirdoftheirnormalriverinegrowthincrement.WhereasthemodestchangesingrowthwithWatanaDamalone(Sec.I.2.1.3.2)wouldprobablybeundetectable.themorestrikingchangesassociatedwithbothdamsoperatingcouldhaveimportantimplicationsforsurvivaloftheemigratingjuvenilesalmon.IftheFERCstaff'sconclusioniscorrectthatautumntemperatureswillfallmorerapidlythantheapplicantestimated.thenthereductioninannualgrowthfrommainstemtemperaturechangeswillbegreater.BelowtheChulitnaconfluence.reducedsummerflowsinthewarmerSusitnaRiverwillcausethelowerSusitnaRivertobecoolerthanpreprojectorwithWatanaDamalone.AsimpledilutionmodelusingmonthlyaveragewatertemperaturesandflowsfortheSusitna.ChulitnaandTalkeetna(TableI.2-1)suggeststhatpotentialJune-Septembergrowthofjuvenilesalmoncouldbereducedbyaboutone-halfcomparedtopreprojectconditions.Alloftheseestimatedeffectswouldbeamelioratedbyfishcongregationinthesloughswhichwouldbesomewhatwarmerthanthemainstem.FoodAvailabilityThemarkedlyincreasedavailabilityoffoodforjuvenilesalmonanticipatedfollowingreductioninturbidityandstabilizationofflowsintheSusitnabyWatanaDammaybereducedbyDevilCanyonDam.Summertemperaturereduction(Sec.4.1.3.2andFigureI.2-3)maybesufficientlyseveretoretardgrowthofbenthicfoodorganisms.WinterEcologyofYoungSalmonidsThemostpronouncedwinterwarmingoftheSusitnawilloccurintheDevilCanyontoTalkeetnareachafterbothWatanaandDevilCanyondamsareinoperation(SeeSec.4.1.3.2).Midwintertemperaturesareexpectedbytheapplicanttoremainnear36°F(2°C)inDevilCanyon.witheventualfreezingbetweenShermanandTalkeetna.Assumingthata41°F(5°C)thresholdforinducingoverwinteringbehaviorappliestoSusitnapopulations(Sec.1.2.1.3.2).then(aswithWatanaalone)themostelevatedtemperaturesinwinterwillbebelowitandanormalbehavioralcyclewilloccur.Thepronouncedlaginautumnalcoolingwithbothdams.however.willdelayonsetofwinterinactivityabout30to40d(dependingondistancedownstreamfromthedam)(FigureI.2-3).AsnotedforWatanaoperations.thesignificanceofthisdelayisunclear.butitmaybebeneficialforoverwinteringsurvivalofchinookandcohosalmon.1-62onlyslightlygreaterthanwithWatanaalone.AnalysesbyFERCstaffindicatethatforninesloughsaboveTalkeetnathefrequencyofoccurrenceofacuteaccesslimitationswillbe67%inJuly.54%inAugust.and55%inSeptember.Theseanalysesalsoindicateareductioninwettedsurfaceareainninesloughsof55%inJuly."39%inAugust.and0%inSeptember(Sec.4.1.1.4.2).GasSupersaturationWithoutconevalves.DevilCanyonDamisprojected(Sec.4.1.3.2)tocreatesupersaturatedconditionsdownstreaminexcessofthe110%lethallimitformostaquaticlife(NAS/NAE1973)forover70%oftheyearswhensummerflowofhydropowerturbinesisaugmentedwithdischargewater.Conevalvesshouldreduceoreliminatethesehighlevels.Withoutconevalvesproposedbytheapplicant.orasimilarmitigativemeasure.highmortalitiesareexpecteddownstreamoftheproject.TheseconditionscouldpersisttotheChulitnaconfluenceandhavesevereconsequencesforthefisheryamountingtonearlycompletelossoffisheryresources.Withconevalves.theseshouldbeinsignificantmortality.EggIncubationRatesatAlteredTemperaturesThethermaleffectsoneggincubationestimatedforWatanaReservoiralone(Sec.1.2.1.3.2)willbesomewhatreducedwithbothdamsinoperationinspiteofadditionalprolongationofwarmtemperaturesintothelateautumnbyDevilCanyonDam.Early-spawningpinkandchumsalmoncouldproduceemergingfryinNovember-Decemberwithbothdamsinoperation(Figure1.2-1.Table1.2-2).LaterspawningfishwouldbemoreaffectedthanwithWatanaalone(Figure1.2-2).Forlatespawners.theprojectedwintermainstemtemperaturesmorecloselyapproximatepreprojectsloughtemperatures.whichmayaidsuccess.especiallyformainstemorside-channelredds.Growth-TemperatureRelationshipsforJuvenileRearingPotentialgrowthofjuvenilesalmondownstreamofDevilCanyonandWatanadamsshowsmarkeddecreaseswhenbothareinoperation(Figure1.2-3.Table1.2-1).Summerpeaktemperaturesarereducedtowellbelowtheoptimalgrowthtemperatureofsalmon(near59°For15°C).andtheprolongedreleaseofabnormallywarmwaterinautumndoesnotcompensateforlostgrowth.Annualgrowthcouldpotentiallyreachonlyabout50%ofpreprojectlevels.Speciesthatemigrateinmidsummercouldaccumulateonlyaboutone-thirdoftheirnormalriverinegrowthincrement.WhereasthemodestchangesingrowthwithWatanaDamalone(Sec.1.2.1.3.2)wouldprobablybeundetectable.themorestrikingchangesassociatedwithbothdamsoperatingcouldhaveimportantimplicationsforsurvivaloftheemigratingjuvenilesalmon.IftheFERCstaff'sconclusioniscorrectthatautumntemperatureswillfallmorerapidlythantheapplicantestimated.thenthereductioninannualgrowthfrommainstemtemperaturechangeswillbegreater.BelowtheChulitnaconfluence.reducedsummerflowsinthewarmerSusitnaRiverwillcausethelowerSusitnaRivertobecoolerthanpreprojectorwithWatanaDamalone.AsimpledilutionmodelusingmonthlyaveragewatertemperaturesandflowsfortheSusitna.ChulitnaandTalkeetna(Table1.2-1)suggeststhatpotentialJune-Septembergrowthofjuvenilesalmoncouldbereducedbyaboutone-halfcomparedtopreprojectconditions.Alloftheseestimatedeffectswouldbeamelioratedbyfishcongregationinthesloughswhichwouldbesomewhatwarmerthanthemainstem.FoodAvailabilityThemarkedlyincreasedavailabilityoffoodforjuvenilesalmonanticipatedfollowingreductioninturbidityandstabilizationofflowsintheSusitnabyWatanaDammaybereducedbyDevilCanyonDam.Summertemperaturereduction(Sec.4.1.3.2andFigure1.2-3)maybesufficientlyseveretoretardgrowthofbenthicfoodorganisms.WinterEcologyofYoungSalmonidsThemostpronouncedwinterwarmingoftheSusitnawilloccurintheDevilCanyontoTalkeetnareachafterbothWatanaandDevilCanyondamsareinoperation(SeeSec.4.1.3.2).Midwintertemperaturesareexpectedbytheapplicanttoremainnear36°F(2°C)inDevilCanyon.witheventualfreezingbetweenShermanandTalkeetna.Assumingthata41°F(5°C)thresholdforinducingoverwinteringbehaviorappliestoSusitnapopulations(Sec.1.2.1.3.2).then(aswithWatanaalone)themostelevatedtemperaturesinwinterwillbebelowitandanormalbehavioralcyclewilloccur.Thepronouncedlaginautumnalcoolingwithbothdams.however.willdelayonsetofwinterinactivityabout30to40d(dependingondistancedownstreamfromthedam)(Figure1.2-3).AsnotedforWatanaoperations.thesignificanceofthisdelayisunclear.butitmaybebeneficialforoverwinteringsurvivalofchinookandcohosalmon. 1-63ReservoirFishCommunityDevilCanyonReservoirwillofferfavorablehabitattofishpopulations,althoughlowproductivitylevelsareanticipatedduetocooltemperaturesandnutrientlimitation.DollyVarden,Arcticgrayling,rainbowandlaketrout,burbot,whitefish,and10ngnosesuckersareanticipated,parallelingtrendsprojectedforWatanaReservoir(Sec.1.2.1.3.2).Drawdown[about50ft(15m)JinAugustandSeptembertomaintainminimumriverflowsdownstreamwillaffectshorelinespawninginsummer.TurbiditylevelslessthaninWatanaReservoirshouldaiddevelopmentoffishpopulations.DependenceofYear-classStrengthonFlowandTemperatureRegimesChangesintheflowandtemperatureregimesdownriverofthetwodamshavebeenidentifiedintheprevioussectionsofthisappendixashavingpotentiallynegativeimpactsonthesalmonstocksutilizingtheDevilCanyontoTalkeetnareachoftheSusitnaRiverforspawningandrearing.Inthissectionhistoricalflow,temperature,andcommercialcatchdatafortheyears1950-1982areanalyzedtodetermineiftherehasbeenanobviousinfluenceoflowflowsinsummerorofloworhightemperaturesinsummerorwinteronyear-classstrengthforanyofthefivesalmonspecies.Specifically,threereasonablehypothesesareasfollows:(1)Isthereatendencyforyear-classstrengthtobebelowaverageforthoseyearclassesexperiencinglowerthanaverageflowsduringthespawningperiodJulythroughSeptember?Themostdirectwayinwhichlowflowscouldreduceyear-classstrengthistorestrictaccesstospawningsitestosuchapointthatspawningsitesbecomelimiting.Ifthisdidoccur,chumandsockeyesalmonarethetwospeciesmostlikelytobeadverselyaffectedsincethesearethetwospeciesthatspawnprimarilyinsloughhabitat.(2)Isthereatendencyforyear-classstrengthtobeabove(below)averageforthoseyearclassesexperiencingwarmer(colder)thanaveragetemperaturesduringthecriticalgrowthperiodofJunethroughAugustafterhatching(i.e.,thesummeroftheyearafterspawning)?Growthduringthisfirstsummerisparticularlycriticalforchumandpinksalmonthatout-migratethatfirstsummer,sincelargersmoltshaveahigherprobabilitythansmallersmoltsofsurvivingandreturningasadultstospawn.Althoughjuvenilechinook,coho,andsockeyeremaininfreshwaterthroughtwoormoresummergrowthperiods,evenforthesethreespeciesgrowthoverthefirstsummerwilltendtobepositivelycorrelatedwithsubsequentsurvival.(3)Isthereatendencyforyear-classstrengthtobeabove(below)averageforthoseyearclassesexperiencingwarmer(colder)thanaveragetemperaturesduringthefirstwinterafterhatching?Thishypothesisappliesonlytochinook,coho,andsockeye,sincechumandpinkout-migratebeforethefirstwinterafterhatching.Survivalfromcoldkillsoverthisfirstwintercanbequitevariablefromyeartoyear,dependingonthetemperatureregimeduringDecemberthroughMarch,thusresultinginacorrespondingvariabilityinyear-classstrength.Thenatureofthehistoricaldataavailablerequiresthatcertainassumptionsandcompromisesbemadetoperformanalysestotesttheabovethreehypotheses.Thebestindexofyear-classstrengthforthefivespeciesofsalmonisthecommercialcatchdataforupperCookInlet.Thesedataareavailablefortheyears1954-1982(Table1.1-7).SusitnaRiverstocksarethoughttocontributethemajorityofthesalmon(exceptforsockeye)tothisfishery,althoughcertainlythereareotherstocksthatspawninotherriversdrainingintoupperCookInlet.Sincethefisherycatchesarecomprisedofanunknownmixtureofstocks,itisappropriatetoviewthecatchdataasaverageindicesofyear-classstrengthforallthesalmonstocksspawninginthevariousriversdrainingintoupperCookInlet,ofwhichtheSusitnaRiveristhelargestandmostimportant.Asecondassumptionmadeconcerningtheuseofcatchdataasindicesofyear-classstrengthisthatforeachspeciesthefisheryoperatesprimarilyonasingleageclassinanyoneyearandthatitisthesameageclasseveryyear.Forpinksalmonthisassumptionisinrealityafact.Fortheotherfourspecies,themajorityofthesalmoncaughtaretypicallyofthesameage(age4forchumandcoho,andage5forchinookandsockeye).Thisassumptionappearstobeleastvalidforchinook(ADF&G,1983a),withagerangingfrom3to6years.Dataforaveragemonthlyflowfortheyears1950-1981atGoldCreekandSusitnaStationwereusedfortheanalysistoevaluatehypothesis(1).WeareassumingthattheseflowsarereasonablerelativeindexesfortheflowsintheothersalmonriversdrainingintoupperCookInlet.Asimilarassumptionwillbemadeforthetemperaturedata,bothwatertemperatureatGoldCreekandairtemperatureatAnchorage.•1-63ReservoirFishCommunityDevilCanyonReservoirwillofferfavorablehabitattofishpopulations,althoughlowproductivitylevelsareanticipatedduetocooltemperaturesandnutrientlimitation.DollyVarden,Arcticgrayling,rainbowandlaketrout,burbot,whitefish,and10ngnosesuckersareanticipated,parallelingtrendsprojectedforWatanaReservoir(Sec.1.2.1.3.2).Drawdown[about50ft(15m)JinAugustandSeptembertomaintainminimumriverflowsdownstreamwillaffectshorelinespawninginsummer.TurbiditylevelslessthaninWatanaReservoirshouldaiddevelopmentoffishpopulations.DependenceofYear-classStrengthonFlowandTemperatureRegimesChangesintheflowandtemperatureregimesdownriverofthetwodamshavebeenidentifiedintheprevioussectionsofthisappendixashavingpotentiallynegativeimpactsonthesalmonstocksutilizingtheDevilCanyontoTalkeetnareachoftheSusitnaRiverforspawningandrearing.Inthissectionhistoricalflow,temperature,andcommercialcatchdatafortheyears1950-1982areanalyzedtodetermineiftherehasbeenanobviousinfluenceoflowflowsinsummerorofloworhightemperaturesinsummerorwinteronyear-classstrengthforanyofthefivesalmonspecies.Specifically,threereasonablehypothesesareasfollows:(1)Isthereatendencyforyear-classstrengthtobebelowaverageforthoseyearclassesexperiencinglowerthanaverageflowsduringthespawningperiodJulythroughSeptember?Themostdirectwayinwhichlowflowscouldreduceyear-classstrengthistorestrictaccesstospawningsitestosuchapointthatspawningsitesbecomelimiting.Ifthisdidoccur,chumandsockeyesalmonarethetwospeciesmostlikelytobeadverselyaffectedsincethesearethetwospeciesthatspawnprimarilyinsloughhabitat.(2)Isthereatendencyforyear-classstrengthtobeabove(below)averageforthoseyearclassesexperiencingwarmer(colder)thanaveragetemperaturesduringthecriticalgrowthperiodofJunethroughAugustafterhatching(i.e.,thesummeroftheyearafterspawning)?Growthduringthisfirstsummerisparticularlycriticalforchumandpinksalmonthatout-migratethatfirstsummer,sincelargersmoltshaveahigherprobabilitythansmallersmoltsofsurvivingandreturningasadultstospawn.Althoughjuvenilechinook,coho,andsockeyeremaininfreshwaterthroughtwoormoresummergrowthperiods,evenforthesethreespeciesgrowthoverthefirstsummerwilltendtobepositivelycorrelatedwithsubsequentsurvival.(3)Isthereatendencyforyear-classstrengthtobeabove(below)averageforthoseyearclassesexperiencingwarmer(colder)thanaveragetemperaturesduringthefirstwinterafterhatching?Thishypothesisappliesonlytochinook,coho,andsockeye,sincechumandpinkout-migratebeforethefirstwinterafterhatching.Survivalfromcoldkillsoverthisfirstwintercanbequitevariablefromyeartoyear,dependingonthetemperatureregimeduringDecemberthroughMarch,thusresultinginacorrespondingvariabilityinyear-classstrength.Thenatureofthehistoricaldataavailablerequiresthatcertainassumptionsandcompromisesbemadetoperformanalysestotesttheabovethreehypotheses.Thebestindexofyear-classstrengthforthefivespeciesofsalmonisthecommercialcatchdataforupperCookInlet.Thesedataareavailablefortheyears1954-1982(Table1.1-7).SusitnaRiverstocksarethoughttocontributethemajorityofthesalmon(exceptforsockeye)tothisfishery,althoughcertainlythereareotherstocksthatspawninotherriversdrainingintoupperCookInlet.Sincethefisherycatchesarecomprisedofanunknownmixtureofstocks,itisappropriatetoviewthecatchdataasaverageindicesofyear-classstrengthforallthesalmonstocksspawninginthevariousriversdrainingintoupperCookInlet,ofwhichtheSusitnaRiveristhelargestandmostimportant.Asecondassumptionmadeconcerningtheuseofcatchdataasindicesofyear-classstrengthisthatforeachspeciesthefisheryoperatesprimarilyonasingleageclassinanyoneyearandthatitisthesameageclasseveryyear.Forpinksalmonthisassumptionisinrealityafact.Fortheotherfourspecies,themajorityofthesalmoncaughtaretypicallyofthesameage(age4forchumandcoho,andage5forchinookandsockeye).Thisassumptionappearstobeleastvalidforchinook(ADF&G,1983a),withagerangingfrom3to6years.Dataforaveragemonthlyflowfortheyears1950-1981atGoldCreekandSusitnaStationwereusedfortheanalysistoevaluatehypothesis(1).WeareassumingthattheseflowsarereasonablerelativeindexesfortheflowsintheothersalmonriversdrainingintoupperCookInlet.Asimilarassumptionwillbemadeforthetemperaturedata,bothwatertemperatureatGoldCreekandairtemperatureatAnchorage.• 1-64Foreachspecies.usingtheappropriatelagbetweenyearofflowthatwouldaffectaccessofspawnerstosloughsandyearofcatchoftheprogenybythecommercialfishery.theanalysisto evaluatehypothesis(1)consistedofcomparingthemeancommercialcatchforlow-flowyearswiththatforhigh-flowyears.TherewerenostatisticallysignificantdifferencesatP=0.05level}.indicatingthatovertherangeofflowsoccurringfrom1950to1981thereisnostrongevidencethatyear-classstrengthforanyofthefivespeciesisadverselyaffectedbylowflowsduringspawning(TableI.2-3).AnimportantcaveatforthisanalysisisthattheaverageflowsatGoldCreekforthelow-flowyears(columnheadedQ1)areallabove12.000ft3/s(340m3/s).whereastheproposedprojectflowsatGoldCreekduringJuly.August.andSeptemberare6.480.12.000.and9.300ft3/s(183.340.and263mS/s).respectively.foranaverageflowof9.260ft3/s(260m3/s).Thereisnosoundbasisforjudgingthevalidityofextrapolatingtheresultsofthisanalysistotheselowerflows.SummaryofEnvironmentalImpactsonSalmonPopulationsfromBothDamsThisdiscussionoftheexpectedlong-termtrendsinsalmonproductionandeffectsofchangesinabundanceofsalmonstocksonfisheriesincludesconsiderationofboththe constructionandoperationphasesofWatanaandDevilCanyondevelopments.Consideringthepotentialcumulativeimpactofchangesinflow,temperature.andturbidityregimesonallstagesofthesalmonlifecyclefrommigrationofadultsthroughout-migrationofsmo1ts.thestaffexpectsthatsalmonproductionaboveTalkeetnaforallfivespecieswillbegreatlyreducedduringthesecondandthirdyearsoffillingofWatanaReservoir.However.thelostproductioninthisreachforthesetwoyearsislikelytobeatleastpartiallyoffsetbyincreasedproductioninothersystemsduetosalmonthatnormallywouldhavecontinuedtomigrateuptheSusitnaRiver.selectingthewarmerwateroftheTalkeetnaRiver.AllfivesalmonspecieswouldbeexpectedtoincreasetheiruseofthisreachoftheSusitnaRiveragainwhenWatanastartsoperating.althoughtherateofreturntohigherproductionlevelswillvaryamongthefivesalmonspeciesdependingonthelifecycleandonthestrengthoftheyearclassesreturningintheyearsimmediatelyfollowingthefillingofWatana.Inthecaseofpinksalmon.noimprintedadultsmaybeavailabletocomebacksincebothodd-yearandeven-yearstockswillbeimpactedduringthesecondandthirdyearsoffilling.andthusrecoverytohigherproductionlevelsislikelytotakemoreyears.ItisnotpossibletoassesswhethertheSusitnaHydroelectricProjectwillresultinanaverage.long-termdecreaseorincreaseinpopulationsofsalmoncurrentlyspawningintheSusitnaRiverbasin.However.itislikelythattherewillbeatleastshort-termdecreasesinsalmonstocksizesduetoconstructionofWatanaandDevilCanyondamsandfillingofWatanaReservoirduetosubstantialchangesinflow.temperature.andturbidityregimes.Basedonthestaff1sanalysis.themagnitudeofanydecrease.especiallyinlightofthevariousmitigationmeasurestobeimplemented(Sec.5.3).willnotbegreat.Nocombinationofimpactshasbeenprojectedthatwouldreducebyasmuchas50%anyofthefivesalmonpopulationsspawningintheSusitnaRiveranditstributariesaboveitsconfluencewiththeTalkeetnaandChulitnarivers.althoughthechum.sockeyeandpinkstocksarelikelytobemoreaffectedthanthechinookandcohosalmonstocks.Conversely.itisnotreasonabletoexpectthattheproposedproject.evenincombinationwithextensivemitigationmeasureswillresultinanincrease.byasmuchas50%.ofanyofthesefivesalmonpopulations.Itisnotpossibletoquantifythedirectimpactoftheprojectonthecommercial.sport.orsubsistencefisheries.exceptthat.otherfactorsbeingequal.changesincatchwillbeapproximatelyproportionaltodecreasesorincreasesinthesizeofthespawningstocks.Otherfactors.however.willnotbeequal.withandwithouttheproject.AsdiscussedinSec.4.1.8.theprojectwilltendtopromoteeconomicandpopulationgrowth.Thesechanges.inturn.willinevitablyincreasefishingeffortbythecommercialandsportfisheries.andprobablythesubsistencefisheryaswell.Theeffectofthisincreasedfishingeffortisrelativelyeasytopredict.basedoncasehistoriesfornumerousotherfishstocksallovertheworld.Increasingexploitationwilleventuallyresultindecreasingfisheryresourcesunlessthereisincreasinginterventionoffisherymanagementpractices.Thislong-termandindirectimpactoftheprojectislikelytomaskanydirectimpactsoftheprojectondownstreamhabitatandthesizeofthefishpopulationsthishabitatcansupport.MercuryLevelsinFishinWatanaandDevilCanyonReservoirsIncreaseshavebeenobservedinmercuryconcentrationsinfishin10newlyimpoundedreservoirsinnorthernManitobathatcannotbeattributedtoatmosphericorindustrialsources(Boda1yandHecky1979.1982;Boda1yeta1.1984).TheseobservedincreasesinmethylmercuryinfishassociatedwiththefloodingofsoilraisesconcernsaboutthepotentialforpostimpoundmentincreasesinmercurylevelsinfishinWatanaandDevilCanyonreservoirstolevelsthatpresentapublichealthrisk.particularlyforsubsistencefishermenwhomayconsumethese1-64Foreachspecies.usingtheappropriatelagbetweenyearofflowthatwouldaffectaccessofspawnerstosloughsandyearofcatchoftheprogenybythecommercialfishery.theanalysisto evaluatehypothesis(1)consistedofcomparingthemeancommercialcatchforlow-flowyearswiththatforhigh-flowyears.TherewerenostatisticallysignificantdifferencesatP=0.05level}.indicatingthatovertherangeofflowsoccurringfrom1950to1981thereisnostrongevidencethatyear-classstrengthforanyofthefivespeciesisadverselyaffectedbylowflowsduringspawning(TableI.2-3).AnimportantcaveatforthisanalysisisthattheaverageflowsatGoldCreekforthelow-flowyears(columnheadedQ1)areallabove12.000ft3/s(340m3/s).whereastheproposedprojectflowsatGoldCreekduringJuly.August.andSeptemberare6.480.12.000.and9.300ft3/s(183.340.and263mS/s).respectively.foranaverageflowof9.260ft3/s(260m3/s).Thereisnosoundbasisforjudgingthevalidityofextrapolatingtheresultsofthisanalysistotheselowerflows.SummaryofEnvironmentalImpactsonSalmonPopulationsfromBothDamsThisdiscussionoftheexpectedlong-termtrendsinsalmonproductionandeffectsofchangesinabundanceofsalmonstocksonfisheriesincludesconsiderationofboththe constructionandoperationphasesofWatanaandDevilCanyondevelopments.Consideringthepotentialcumulativeimpactofchangesinflow,temperature.andturbidityregimesonallstagesofthesalmonlifecyclefrommigrationofadultsthroughout-migrationofsmo1ts.thestaffexpectsthatsalmonproductionaboveTalkeetnaforallfivespecieswillbegreatlyreducedduringthesecondandthirdyearsoffillingofWatanaReservoir.However.thelostproductioninthisreachforthesetwoyearsislikelytobeatleastpartiallyoffsetbyincreasedproductioninothersystemsduetosalmonthatnormallywouldhavecontinuedtomigrateuptheSusitnaRiver.selectingthewarmerwateroftheTalkeetnaRiver.AllfivesalmonspecieswouldbeexpectedtoincreasetheiruseofthisreachoftheSusitnaRiveragainwhenWatanastartsoperating.althoughtherateofreturntohigherproductionlevelswillvaryamongthefivesalmonspeciesdependingonthelifecycleandonthestrengthoftheyearclassesreturningintheyearsimmediatelyfollowingthefillingofWatana.Inthecaseofpinksalmon.noimprintedadultsmaybeavailabletocomebacksincebothodd-yearandeven-yearstockswillbeimpactedduringthesecondandthirdyearsoffilling.andthusrecoverytohigherproductionlevelsislikelytotakemoreyears.ItisnotpossibletoassesswhethertheSusitnaHydroelectricProjectwillresultinanaverage.long-termdecreaseorincreaseinpopulationsofsalmoncurrentlyspawningintheSusitnaRiverbasin.However.itislikelythattherewillbeatleastshort-termdecreasesinsalmonstocksizesduetoconstructionofWatanaandDevilCanyondamsandfillingofWatanaReservoirduetosubstantialchangesinflow.temperature.andturbidityregimes.Basedonthestaff1sanalysis.themagnitudeofanydecrease.especiallyinlightofthevariousmitigationmeasurestobeimplemented(Sec.5.3).willnotbegreat.Nocombinationofimpactshasbeenprojectedthatwouldreducebyasmuchas50%anyofthefivesalmonpopulationsspawningintheSusitnaRiveranditstributariesaboveitsconfluencewiththeTalkeetnaandChulitnarivers.althoughthechum.sockeyeandpinkstocksarelikelytobemoreaffectedthanthechinookandcohosalmonstocks.Conversely.itisnotreasonabletoexpectthattheproposedproject.evenincombinationwithextensivemitigationmeasureswillresultinanincrease.byasmuchas50%.ofanyofthesefivesalmonpopulations.Itisnotpossibletoquantifythedirectimpactoftheprojectonthecommercial.sport.orsubsistencefisheries.exceptthat.otherfactorsbeingequal.changesincatchwillbeapproximatelyproportionaltodecreasesorincreasesinthesizeofthespawningstocks.Otherfactors.however.willnotbeequal.withandwithouttheproject.AsdiscussedinSec.4.1.8.theprojectwilltendtopromoteeconomicandpopulationgrowth.Thesechanges.inturn.willinevitablyincreasefishingeffortbythecommercialandsportfisheries.andprobablythesubsistencefisheryaswell.Theeffectofthisincreasedfishingeffortisrelativelyeasytopredict.basedoncasehistoriesfornumerousotherfishstocksallovertheworld.Increasingexploitationwilleventuallyresultindecreasingfisheryresourcesunlessthereisincreasinginterventionoffisherymanagementpractices.Thislong-termandindirectimpactoftheprojectislikelytomaskanydirectimpactsoftheprojectondownstreamhabitatandthesizeofthefishpopulationsthishabitatcansupport.MercuryLevelsinFishinWatanaandDevilCanyonReservoirsIncreaseshavebeenobservedinmercuryconcentrationsinfishin10newlyimpoundedreservoirsinnorthernManitobathatcannotbeattributedtoatmosphericorindustrialsources(Boda1yandHecky1979.1982;Boda1yeta1.1984).TheseobservedincreasesinmethylmercuryinfishassociatedwiththefloodingofsoilraisesconcernsaboutthepotentialforpostimpoundmentincreasesinmercurylevelsinfishinWatanaandDevilCanyonreservoirstolevelsthatpresentapublichealthrisk.particularlyforsubsistencefishermenwhomayconsumethese 1-65Table1.2-3.AnalysistoTesttheHypothesisforEachofFiveSalmonSpeciesthatThereisaTendencyforYear-ClassStrengthtobeBelowAverageforThoseYearClassesExperiencingLowerthanAverageFlowsDuringtheSpawningPeriodJulythroughSeptembertlSpeciesStationNl01ClN202C2MAXMINGTA.Thelowest25%oftheflowsversusthehighest25%oftheflows.ChinookGoldCreek815,60414,68:;723,80713,0131.52570-0.2841ChinookSusitna884,88316,9587119,43514,2701.40705-0.4962SockeyeGoldCreek815,6041,070,251723,8071,062,2521.52570-0.0282SockeyeSusitna884,883834,3847119,4351,398,9281.407051.7272CohoGoldCreek815,337321,186823,626209,2821.54046-1.2840CohoSusitna884,883244,4938118,650229,8881.39781-0.2152Pink(even)GoldCreek415,6561,705,368422,7682,095,2921.454270.6842Pink(even)Susitna485,4411,441,0784123,2251,964,6971.442220.9131Pink(odd)GoldCreek415,710136,661324,42030,4671.55442-1.3205Pink(odd)Susitna487,246256,9623118,81339,6441.36182-1.5448ChumGoldCreek815,337789,369823,626533,8931.54046-1.3856ChumSusitna884,883732,2458118,650540,0011.39781-1.4826B.Thelowest10%oftheflowsversusthehighest50%oftheflows.ChinookGoldCreek313,66310,6271422,46218,4341.644000.7819ChinookSusitna377,4348,50914114,38114,7151.477140.9735SockeyeGoldCreek313,663954,9651422,4621,193,9021.644001.0056SockeyeSusitna377,434697,20814114,3811,270,9751.477141.4343CohoGoldCreek313,523388,3921522,284207,2831.64786-1.8791CohoSusitna377,434134,86215113,680224,5001.468091.2286Pink(even)GoldCreek215,2731,779,075721,3741,807,0831.399460.0381Pink(even)Susitna283,0561,035,3207116,5021,827,7761.402691.1065Pink(odd)GoldCreek212,948185,992623,66678,5071.82777-0.9349Pink(odd)Susitna277,71768,6526117,129101,165 1.507120.3653ChumGoldCreek313,523827,7571522,284508,0991.64786-1.6261ChumSusitna377,434623,21515113,680530,8321.46809-0.5847tlElaborationofcolumnheadings:Species:Pink(even)=pinksalmonspawningineven-numberedyears;pink(odd)=pinksalmonspawninginodd-numberedyears.Station:SitesforflowmeasurementsareGoldCreekandSusitnaStation.Nlisthenumberofyearsinthesampleoflow-flowyears;N2isthenumberofyearsinthesampleofhigh-flowyears.01istheaverageflow(ft3/s)forthesampleoflow-flowyears;02istheaverageflowforthesampleofhigh-flowyears.Inbothcases,theflowusedforeachyearistheaverageofJuly,August,andSeptembermeanflows.Clistheaveragecommercialcatch(numbersofsalmon)inupperCookInletforthesampleoflow-flowyears;C2istheaveragecommercialcatchforthesampleofhigh-flowyears.MAXMINO=02/01.Tisthet-teststatisticcalculatedfromthesampledata.Itiscomparedwithone-taTledtabulatedtvaluesfor(Nl+N2-2)degreesoffreedomtodeterminetheprobabilityofobservTnga tvaluethislargeorlargerifthenullhypothesisofequalcommercialcatchesforlow-flowandhigh-flowyearsistrue.Conversion:Toconvertfromcubicfeetpersecondtocubicmeterspersecond,multiplyby0.028831.Source:FERCstaff.1-65Table1.2-3.AnalysistoTesttheHypothesisforEachofFiveSalmonSpeciesthatThereisaTendencyforYear-ClassStrengthtobeBelowAverageforThoseYearClassesExperiencingLowerthanAverageFlowsDuringtheSpawningPeriodJulythroughSeptembertlSpeciesStationNl01ClN202C2MAXMINGTA.Thelowest25%oftheflowsversusthehighest25%oftheflows.ChinookGoldCreek815,60414,68:;723,80713,0131.52570-0.2841ChinookSusitna884,88316,9587119,43514,2701.40705-0.4962SockeyeGoldCreek815,6041,070,251723,8071,062,2521.52570-0.0282SockeyeSusitna884,883834,3847119,4351,398,9281.407051.7272CohoGoldCreek815,337321,186823,626209,2821.54046-1.2840CohoSusitna884,883244,4938118,650229,8881.39781-0.2152Pink(even)GoldCreek415,6561,705,368422,7682,095,2921.454270.6842Pink(even)Susitna485,4411,441,0784123,2251,964,6971.442220.9131Pink(odd)GoldCreek415,710136,661324,42030,4671.55442-1.3205Pink(odd)Susitna487,246256,9623118,81339,6441.36182-1.5448ChumGoldCreek815,337789,369823,626533,8931.54046-1.3856ChumSusitna884,883732,2458118,650540,0011.39781-1.4826B.Thelowest10%oftheflowsversusthehighest50%oftheflows.ChinookGoldCreek313,66310,6271422,46218,4341.644000.7819ChinookSusitna377,4348,50914114,38114,7151.477140.9735SockeyeGoldCreek313,663954,9651422,4621,193,9021.644001.0056SockeyeSusitna377,434697,20814114,3811,270,9751.477141.4343CohoGoldCreek313,523388,3921522,284207,2831.64786-1.8791CohoSusitna377,434134,86215113,680224,5001.468091.2286Pink(even)GoldCreek215,2731,779,075721,3741,807,0831.399460.0381Pink(even)Susitna283,0561,035,3207116,5021,827,7761.402691.1065Pink(odd)GoldCreek212,948185,992623,66678,5071.82777-0.9349Pink(odd)Susitna277,71768,6526117,129101,165 1.507120.3653ChumGoldCreek313,523827,7571522,284508,0991.64786-1.6261ChumSusitna377,434623,21515113,680530,8321.46809-0.5847tlElaborationofcolumnheadings:Species:Pink(even)=pinksalmonspawningineven-numberedyears;pink(odd)=pinksalmonspawninginodd-numberedyears.Station:SitesforflowmeasurementsareGoldCreekandSusitnaStation.Nlisthenumberofyearsinthesampleoflow-flowyears;N2isthenumberofyearsinthesampleofhigh-flowyears.01istheaverageflow(ft3/s)forthesampleoflow-flowyears;02istheaverageflowforthesampleofhigh-flowyears.Inbothcases,theflowusedforeachyearistheaverageofJuly,August,andSeptembermeanflows.Clistheaveragecommercialcatch(numbersofsalmon)inupperCookInletforthesampleoflow-flowyears;C2istheaveragecommercialcatchforthesampleofhigh-flowyears.MAXMINO=02/01.Tisthet-teststatisticcalculatedfromthesampledata.Itiscomparedwithone-taTledtabulatedtvaluesfor(Nl+N2-2)degreesoffreedomtodeterminetheprobabilityofobservTnga tvaluethislargeorlargerifthenullhypothesisofequalcommercialcatchesforlow-flowandhigh-flowyearsistrue.Conversion:Toconvertfromcubicfeetpersecondtocubicmeterspersecond,multiplyby0.028831.Source:FERCstaff. 1-66fishonasustainedbasis.Thebasisforconcernisthatthereportedincreasesoccurredcoincidentlywithfloodingandwererelatedtothefloodedterrestrialarea,suggestingthatthesoilwasthesourceoftheelevatedmercury.Becausemercurylevelsinfishfromnearbyunfloodedlakesdidnotincrease,atmosphericfalloutwaseliminatedasacauseoftheproblem.Mercurylevelsinpredatoryfishspeciesfromallofthefloodedlakeswerenearto,orexceeded,theFoodandDrugAdministration's"actionlevel"of1.0ppm(~g/g)freshweightofmercuryintheedibleportionoffishflesh.Itwashypothesizedthattheincreasedmercurylevelsinfishwereduetobacterialmethylationofnaturallyoccurringmercuryinnewlyfloodedsoilsandsuspendedsediments.BasedonthereportedpostimpoundmentincreasesofmercuryinfishinnorthernManitoba,itappearslikelythatmercurylevelswillincreaseinfishafterimpoundmentinWatanaandDevilCanyonandthatmonitoringofmercurylevelsinfishfromtheseimpoundmentswillbenecessary.1.2.3AccessRoutes1.2.3.1PlantCommunitiesIncreasedturbidityandsiltationassociatedwithstreamcrossingsbyaccessrouteswillresultinsomedegradationandlossofhabitatutilizedbybenthicalgaeandperiphyton.Theseimpactswillbeduetoreducedlightpenetration,scouring,andsedimentcoveringsuitablesubstrate.Somechangesinspeciescompositionmayoccurlocally.Althoughthesetypesofimpactscannotbecompletelyavoided,theycanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningtheplantcommunitiesinthesestreamsandthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.3.2InvertebrateCommunitiesIncreasedturbidityandsiltationassociatedwithstreamcrossingsbyaccessrouteswillresultinsomedegradationandlossofhabitatutilizedbyinvertebrates.Thisimpactwillbeduetoboththedirecteffectsofscouring,cloggingoffeedingmechanismsbysilt,andcoveringofsuitablesubstratebysedimentandtheindirecteffectsontheavailabilityofplantfoodforinvertebratesbecauseoflocalreductionsinthesizeandproductivityofplantcommunities.Somechangesinspeciescompositionmayoccurlocally.Althoughthesetypesofimpactscannotbecompletelyavoided,theimpactscanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.3.3FishCommunitiesTherearetwoenvironmentalimpactstobeassessedforfishcommunitiesinstreamsandlakesinthevicinityoftheaccessroutes.Thegreatestsourceofadverseimpactonfishcommunitieswillbetheincreasedaccessibilityofthesestreamsandlakestofishingpressureviathenetworkofaccessroutes.Asanexample,theWatanaaccessroadwillcrossBrushkana,Lily,Seattle,andDeadmancreeksaswellasothersmall,unnamedstreams.Thesecreeksareclear-waterstreamsandmanyareinhabitedbygrayling.DeadmanCreek,inparticular,isknownforitsabundantandtrophy-sizedgrayling.ThereachofDeadmanCreekbetweenthefallsandDeadmanLakeisconsideredprimegraylinghabit.Bysubjectingthisstreamtoincreasedfishingpressure,manyofthelarger,olderfishwillberemovedfromthepopulation,alteringtheagestructureandpossiblyreducingreproductivepotential.Asimilarimpactmayoccurtoothergraylingstreamsinthearea.Anotherimpactassociatedwithaccessroadsandrailroads,asidentifiedbytheapplicantandthevariousagenciesconcernedwithfisheryresources,istheeffectonresidentfishpopulations,graylinginparticular,ofincreasedturbidityandsiltationassociatedwithstreamcrossings.Thebasesforthisconcernarethattherewillbenumerous(apprOXimately100)streamcrossingsandthatincreasedturbidityandsiltationarelikelytoresultindegradationandlossofhabitat,especiallyhabitatcurrentlyusedforspawningandrearingofjuveniles.ThestreamsofconcernaredescribedinSecs.3.1.4.5and1.1.Fishwilltendtoavoidareaswherein-streamworkisbeingconducted,areascontaminatedbypetroleumproducts,orareasexperiencingexcessiveturbidityandsiltation.Barrierstofishmovementsandmigrationsmaybecreatedwhenstreamsarediverted,flumed,orblockedduringinstallationofdrainagestructures.Fishcanalsobepreventedfrommovingupstreamifdrainagestructuresareincorrectlyinstalled.Pumpingofwaterfromstreamscanadverselyaffectlocalpopulationsbyentrainingjuvenilefish.Clearingwillremoveoverhangingvegetationthatprovidescoverforfish.1-66fishonasustainedbasis.Thebasisforconcernisthatthereportedincreasesoccurredcoincidentlywithfloodingandwererelatedtothefloodedterrestrialarea,suggestingthatthesoilwasthesourceoftheelevatedmercury.Becausemercurylevelsinfishfromnearbyunfloodedlakesdidnotincrease,atmosphericfalloutwaseliminatedasacauseoftheproblem.Mercurylevelsinpredatoryfishspeciesfromallofthefloodedlakeswerenearto,orexceeded,theFoodandDrugAdministration's"actionlevel"of1.0ppm(~g/g)freshweightofmercuryintheedibleportionoffishflesh.Itwashypothesizedthattheincreasedmercurylevelsinfishwereduetobacterialmethylationofnaturallyoccurringmercuryinnewlyfloodedsoilsandsuspendedsediments.BasedonthereportedpostimpoundmentincreasesofmercuryinfishinnorthernManitoba,itappearslikelythatmercurylevelswillincreaseinfishafterimpoundmentinWatanaandDevilCanyonandthatmonitoringofmercurylevelsinfishfromtheseimpoundmentswillbenecessary.1.2.3AccessRoutes1.2.3.1PlantCommunitiesIncreasedturbidityandsiltationassociatedwithstreamcrossingsbyaccessrouteswillresultinsomedegradationandlossofhabitatutilizedbybenthicalgaeandperiphyton.Theseimpactswillbeduetoreducedlightpenetration,scouring,andsedimentcoveringsuitablesubstrate.Somechangesinspeciescompositionmayoccurlocally.Althoughthesetypesofimpactscannotbecompletelyavoided,theycanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningtheplantcommunitiesinthesestreamsandthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.3.2InvertebrateCommunitiesIncreasedturbidityandsiltationassociatedwithstreamcrossingsbyaccessrouteswillresultinsomedegradationandlossofhabitatutilizedbyinvertebrates.Thisimpactwillbeduetoboththedirecteffectsofscouring,cloggingoffeedingmechanismsbysilt,andcoveringofsuitablesubstratebysedimentandtheindirecteffectsontheavailabilityofplantfoodforinvertebratesbecauseoflocalreductionsinthesizeandproductivityofplantcommunities.Somechangesinspeciescompositionmayoccurlocally.Althoughthesetypesofimpactscannotbecompletelyavoided,theimpactscanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.3.3FishCommunitiesTherearetwoenvironmentalimpactstobeassessedforfishcommunitiesinstreamsandlakesinthevicinityoftheaccessroutes.Thegreatestsourceofadverseimpactonfishcommunitieswillbetheincreasedaccessibilityofthesestreamsandlakestofishingpressureviathenetworkofaccessroutes.Asanexample,theWatanaaccessroadwillcrossBrushkana,Lily,Seattle,andDeadmancreeksaswellasothersmall,unnamedstreams.Thesecreeksareclear-waterstreamsandmanyareinhabitedbygrayling.DeadmanCreek,inparticular,isknownforitsabundantandtrophy-sizedgrayling.ThereachofDeadmanCreekbetweenthefallsandDeadmanLakeisconsideredprimegraylinghabit.Bysubjectingthisstreamtoincreasedfishingpressure,manyofthelarger,olderfishwillberemovedfromthepopulation,alteringtheagestructureandpossiblyreducingreproductivepotential.Asimilarimpactmayoccurtoothergraylingstreamsinthearea.Anotherimpactassociatedwithaccessroadsandrailroads,asidentifiedbytheapplicantandthevariousagenciesconcernedwithfisheryresources,istheeffectonresidentfishpopulations,graylinginparticular,ofincreasedturbidityandsiltationassociatedwithstreamcrossings.Thebasesforthisconcernarethattherewillbenumerous(apprOXimately100)streamcrossingsandthatincreasedturbidityandsiltationarelikelytoresultindegradationandlossofhabitat,especiallyhabitatcurrentlyusedforspawningandrearingofjuveniles.ThestreamsofconcernaredescribedinSecs.3.1.4.5and1.1.Fishwilltendtoavoidareaswherein-streamworkisbeingconducted,areascontaminatedbypetroleumproducts,orareasexperiencingexcessiveturbidityandsiltation.Barrierstofishmovementsandmigrationsmaybecreatedwhenstreamsarediverted,flumed,orblockedduringinstallationofdrainagestructures.Fishcanalsobepreventedfrommovingupstreamifdrainagestructuresareincorrectlyinstalled.Pumpingofwaterfromstreamscanadverselyaffectlocalpopulationsbyentrainingjuvenilefish.Clearingwillremoveoverhangingvegetationthatprovidescoverforfish. 1-67Theapplicant'sapproachtominimizingincreasesinturbidityandsiltationisevaluatedinSec.4.1.3.2.Althoughthesetypesofimpactscannotbecompletelyavoided,theimpactscanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)ofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.4PowerTransmissionFacilities1.2.4.1PlantCommunitiesIncreasedturbidityandsiltationassociatedwithstreamcrossingsbytransmissioncorridorswillresultinsomedegradationandlossofhabitatutilizedbybenthicalgaeandperiphyton.Theseimpactswillbeduetoreducedlightpenetration,scouring,andsedimentcoveringsuitablesubstrate.Somechangesinspeciescompositionmayoccurlocally.Althoughthesetypesofimpactscannotbecompletelyavoided,theycanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.4.2InvertebrateCommunitiesAsforplantcommunities,increasedturbidityandsiltationassociatedwithstreamcrossingsbytransmissioncorridorswillresultinsomedegradationandlossofhabitatutilizedbyinvertebrates.Thisimpactwillbeduetoboththedirecteffectsofscouring,cloggingoffeedingmechanismsbysilt,andsedimentcoveringsuitablesubstrateandtheindirecteffectsontheavailabilityofplantfoodforinvertebratesbecauseoflocalreductionsinthesizeandproductivityofplantcommunities.1.2.4.3FishCommunitiesThesametwoenvironmentalimpactsonfishcommunitiesidentifiedforaccessroutes(Sec.4.1.3.5.3)mustalsobeconsideredforthepowertransmissionfacilities.Becausethevegetationalongthetransmissioncorridorsiskeptrelativelylow,hikersandallterrainvehiclescanusethecorridorsastrails.Thiswillresultingreaternumbersoffishermenbeingabletoreachareasthatpreviouslyexperiencedlittleornofishingpressure.Thiseffectwillbemoreacuteinareaswherethenewtransmissionroutedivergesfromexistingroadsandtransmissionlines,suchassouthofWillowandnorthofHealy.Thesecondsourceofimpactonfishcommunitieswillbeincreasedturbidityandsiltationassociatedwithstreamcrossings(seeSec.4.1.3.5.3).Theapplicant'sapproachtomitigationofthisimpactisevaluatedinSec.2.1.8.Althoughincreasesinturbidityandsiltationcannotbecompletelyavoided,theimpactscanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.REFERENCESFORAPPENDIXIAcresAmerican,Inc.(Acres).1983.SloughHydrogeologyReport(Draft).PreparedforAlaskaPowerAuthority,Anchorage,AK.Avnime1ech,Y.,B.W.TroegerandL.W.Reed.1982.Mutualflocculationofalgaeandclay:evidenceandimplications.Science216:63-65.AlaskaDepartmentofFishandGame(ADF&G).1981a.AdultAnadromousPhase1FinalSpecies/SubjectReport.SusitnaHydroAquaticStudies.Anchorage,AK.AlaskaDepartmentofFishandGame(ADF&G).1981b.Phase1FinalDraftReport,AdultAnadromousFisheriesProject.SusitnaHydroAquaticStudies,1981.Anchorage,AK.(PreparedforAlaskaPowerAuthority).AlaskaDepartmentofFishandGame(ADF&G).1981c.Phase1FinalDraftReport,AquaticHabitatandInstreamFlowProject.VolumeI.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1981d.Phase1FinalDraftReport,JuvenileAnadromousFishStudyontheLowerSusitnaRiver.SusitnaHydroAquaticStudies,1981.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).1-67Theapplicant'sapproachtominimizingincreasesinturbidityandsiltationisevaluatedinSec.4.1.3.2.Althoughthesetypesofimpactscannotbecompletelyavoided,theimpactscanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)ofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.4PowerTransmissionFacilities1.2.4.1PlantCommunitiesIncreasedturbidityandsiltationassociatedwithstreamcrossingsbytransmissioncorridorswillresultinsomedegradationandlossofhabitatutilizedbybenthicalgaeandperiphyton.Theseimpactswillbeduetoreducedlightpenetration,scouring,andsedimentcoveringsuitablesubstrate.Somechangesinspeciescompositionmayoccurlocally.Althoughthesetypesofimpactscannotbecompletelyavoided,theycanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.Giventhelimitedinformationcurrentlyavailablefromtheapplicantconcerningthenumber,location,anddesignoftheactualcrossings,itisnotpossibletoquantitativelyestimatetheabsoluteorrelativeamountofstreamhabitatthatwillbedegradedorlost,butitisnotexpectedtobegreat.Theseimpactswilloccurprimarilyduringtheconstructionphasewhenthestreamcrossingsarebeingbuilt.1.2.4.2InvertebrateCommunitiesAsforplantcommunities,increasedturbidityandsiltationassociatedwithstreamcrossingsbytransmissioncorridorswillresultinsomedegradationandlossofhabitatutilizedbyinvertebrates.Thisimpactwillbeduetoboththedirecteffectsofscouring,cloggingoffeedingmechanismsbysilt,andsedimentcoveringsuitablesubstrateandtheindirecteffectsontheavailabilityofplantfoodforinvertebratesbecauseoflocalreductionsinthesizeandproductivityofplantcommunities.1.2.4.3FishCommunitiesThesametwoenvironmentalimpactsonfishcommunitiesidentifiedforaccessroutes(Sec.4.1.3.5.3)mustalsobeconsideredforthepowertransmissionfacilities.Becausethevegetationalongthetransmissioncorridorsiskeptrelativelylow,hikersandallterrainvehiclescanusethecorridorsastrails.Thiswillresultingreaternumbersoffishermenbeingabletoreachareasthatpreviouslyexperiencedlittleornofishingpressure.Thiseffectwillbemoreacuteinareaswherethenewtransmissionroutedivergesfromexistingroadsandtransmissionlines,suchassouthofWillowandnorthofHealy.Thesecondsourceofimpactonfishcommunitieswillbeincreasedturbidityandsiltationassociatedwithstreamcrossings(seeSec.4.1.3.5.3).Theapplicant'sapproachtomitigationofthisimpactisevaluatedinSec.2.1.8.Althoughincreasesinturbidityandsiltationcannotbecompletelyavoided,theimpactscanbelimitedtotheimmediatevicinity[e.g.,100yard(100m)Jofstreamcrossings.REFERENCESFORAPPENDIXIAcresAmerican,Inc.(Acres).1983.SloughHydrogeologyReport(Draft).PreparedforAlaskaPowerAuthority,Anchorage,AK.Avnime1ech,Y.,B.W.TroegerandL.W.Reed.1982.Mutualflocculationofalgaeandclay:evidenceandimplications.Science216:63-65.AlaskaDepartmentofFishandGame(ADF&G).1981a.AdultAnadromousPhase1FinalSpecies/SubjectReport.SusitnaHydroAquaticStudies.Anchorage,AK.AlaskaDepartmentofFishandGame(ADF&G).1981b.Phase1FinalDraftReport,AdultAnadromousFisheriesProject.SusitnaHydroAquaticStudies,1981.Anchorage,AK.(PreparedforAlaskaPowerAuthority).AlaskaDepartmentofFishandGame(ADF&G).1981c.Phase1FinalDraftReport,AquaticHabitatandInstreamFlowProject.VolumeI.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1981d.Phase1FinalDraftReport,JuvenileAnadromousFishStudyontheLowerSusitnaRiver.SusitnaHydroAquaticStudies,1981.Anchorage,AK.(PreparedforAcresAmerican,Incorporated). 1-68AlaskaDepartmentofFishandGame(ADF&G).1981e.Phase1FinalDraftReport,ResidentFishInvestigationontheLowerSusitnaRiver.SusitnaHydroAquaticStudies,1981.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1981f.Phase1FinalDraftReport,ResidentFishInvestigationontheUpperSusitnaRiver.SusitnaHydroAquaticStudies.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1982a.Phase1FinalDraftReport,AquaticStudiesProgram.SusitnaHydroAquaticStudies.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1982b.Phase1FinalDraftStockSeparationFeasibilityReport,AdultAnadromousFisheries Project.SusitnaHydroAquaticStudies.Anchorage,AK.(PreparedforAlaskaPowerAuthority).AlaskaDepartmentofFishandGame(ADF&G).1983a.Synposisofthe1982AquaticStudiesandAnalysisofFishandHabitatRelationships.SusitnaHydroAquaticStudies,PhaseIIReport,Anchorage,AK.152pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983b.AdultAnadromousFishStudies,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.2(2parts).Anchorage,AK.239pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983c.ResidentandJuvenileAnadromousFishStudiesontheSusitnaRiverBelowDevilCanyon,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.3(2parts).Anchorage,AK.277pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983d.AquaticHabitatandInstreamFlowStudies,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.4(2parts).Anchorage,AK.267pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983e.UpperSusitnaRiverImpoundmentStudies,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.5.Anchorage,AK.150pp.plusappendices.Alt,K.T.1973.ContributionstobiologyoftheBeringcisco(Coregonuslaurettae)inAlaska.J.Fish.Res.BoardCan.30:1885-1888.Bakkala,RichardG.1970.SynopsisofBiologicalDataontheChumSalmon,Oncorhynchusketa(Walbaum)1792.FAOSpeciesSynopsisNo.41.U.S.FishWildl.Serv.,BureauComm.Fish.Circ.315.Washington,DC.89pp.Barrett,B.M.1974.AnAssessmentoftheAnadromousFishPopulationsintheupperSusitnaRiverWatershedBetweenDevilCanyonandtheChulitnaRiver.AlaskaDepartmentofFishandGame,DivisionofCommercialFisheries,Anchorage,AK.56pp.Battle,H.I.1944.TheembryologyoftheAtlanticsalmon(SalmosalarLinnaeus).Can.J.Res.Sect.D.22(5):105-125.------------Bauersfeld,K.1978.StrandingofJuvenileSalmonbyFlowReductionsatMayfieldDamontheCowlitzRiver,1976.Wash.Dept.Fish.,Tech.Rep.No.36.36pp.BechtelCivilandMinerals,Inc.1983.ChakachamnaHydroelectricProjectInterimReport.PreparedforAlaskaPowerAuthority,Anchorage,AK.Becker,C.D.1973.FoodandgrowthparametersofjuvenilechinooksalmonOncorhnchustshawytschaincentralColumbiaRiver.Nat.OceanicAtmops.Admin.(U.S.Fish.Bull.71(2):387-400.Becker,C.D.,D.A.NeitzelandD.H.Fickeisen.1982.Effectsofdewateringonchinooksalmonredds:Toleranceoffourdevelopmentalphasestodailydewaterings.Trans.Am.Fish.Soc.111:624-637.Bell,MiloC.1973.FisheriesHandbookofEngineeringRequirementsandBiologicalCriteria.FisheriesEngineeringResearchProgram.U.S.ArmyCorpsofEngineers,NorthPacificDivision,Portland,OR.34chapters.Bernard,D.R.,G.Oliver,W.GoshertandB.Cross.1983.ComparisonofScalePatternsfromSockeyeSalmonSampledfromDifferentRiverswithintheSusitnaRiverWatershedin1982.AlaskaDepartmentofFishandGame,DivisionofCommercialFisheries,StatewideStockBiologyGroup,Anchorage,AK.22pp.1-68AlaskaDepartmentofFishandGame(ADF&G).1981e.Phase1FinalDraftReport,ResidentFishInvestigationontheLowerSusitnaRiver.SusitnaHydroAquaticStudies,1981.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1981f.Phase1FinalDraftReport,ResidentFishInvestigationontheUpperSusitnaRiver.SusitnaHydroAquaticStudies.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1982a.Phase1FinalDraftReport,AquaticStudiesProgram.SusitnaHydroAquaticStudies.Anchorage,AK.(PreparedforAcresAmerican,Incorporated).AlaskaDepartmentofFishandGame(ADF&G).1982b.Phase1FinalDraftStockSeparationFeasibilityReport,AdultAnadromousFisheries Project.SusitnaHydroAquaticStudies.Anchorage,AK.(PreparedforAlaskaPowerAuthority).AlaskaDepartmentofFishandGame(ADF&G).1983a.Synposisofthe1982AquaticStudiesandAnalysisofFishandHabitatRelationships.SusitnaHydroAquaticStudies,PhaseIIReport,Anchorage,AK.152pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983b.AdultAnadromousFishStudies,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.2(2parts).Anchorage,AK.239pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983c.ResidentandJuvenileAnadromousFishStudiesontheSusitnaRiverBelowDevilCanyon,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.3(2parts).Anchorage,AK.277pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983d.AquaticHabitatandInstreamFlowStudies,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.4(2parts).Anchorage,AK.267pp.plusappendices.AlaskaDepartmentofFishandGame(ADF&G).1983e.UpperSusitnaRiverImpoundmentStudies,1982.SusitnaHydroAquaticStudies,PhaseIIReport,Vol.5.Anchorage,AK.150pp.plusappendices.Alt,K.T.1973.ContributionstobiologyoftheBeringcisco(Coregonuslaurettae)inAlaska.J.Fish.Res.BoardCan.30:1885-1888.Bakkala,RichardG.1970.SynopsisofBiologicalDataontheChumSalmon,Oncorhynchusketa(Walbaum)1792.FAOSpeciesSynopsisNo.41.U.S.FishWildl.Serv.,BureauComm.Fish.Circ.315.Washington,DC.89pp.Barrett,B.M.1974.AnAssessmentoftheAnadromousFishPopulationsintheupperSusitnaRiverWatershedBetweenDevilCanyonandtheChulitnaRiver.AlaskaDepartmentofFishandGame,DivisionofCommercialFisheries,Anchorage,AK.56pp.Battle,H.I.1944.TheembryologyoftheAtlanticsalmon(SalmosalarLinnaeus).Can.J.Res.Sect.D.22(5):105-125.------------Bauersfeld,K.1978.StrandingofJuvenileSalmonbyFlowReductionsatMayfieldDamontheCowlitzRiver,1976.Wash.Dept.Fish.,Tech.Rep.No.36.36pp.BechtelCivilandMinerals,Inc.1983.ChakachamnaHydroelectricProjectInterimReport.PreparedforAlaskaPowerAuthority,Anchorage,AK.Becker,C.D.1973.FoodandgrowthparametersofjuvenilechinooksalmonOncorhnchustshawytschaincentralColumbiaRiver.Nat.OceanicAtmops.Admin.(U.S.Fish.Bull.71(2):387-400.Becker,C.D.,D.A.NeitzelandD.H.Fickeisen.1982.Effectsofdewateringonchinooksalmonredds:Toleranceoffourdevelopmentalphasestodailydewaterings.Trans.Am.Fish.Soc.111:624-637.Bell,MiloC.1973.FisheriesHandbookofEngineeringRequirementsandBiologicalCriteria.FisheriesEngineeringResearchProgram.U.S.ArmyCorpsofEngineers,NorthPacificDivision,Portland,OR.34chapters.Bernard,D.R.,G.Oliver,W.GoshertandB.Cross.1983.ComparisonofScalePatternsfromSockeyeSalmonSampledfromDifferentRiverswithintheSusitnaRiverWatershedin1982.AlaskaDepartmentofFishandGame,DivisionofCommercialFisheries,StatewideStockBiologyGroup,Anchorage,AK.22pp. 1-69Bilton,H.T.1971.IdentificationofmajorBritishColumbiaandAlaskarunsofeven-yearandodd-yearpinksalmonfromscalecharacters.J.Fish.Res.BoardCan.29:295-301.Bjornn,T.C.1969.SalmonandSteelheadInvestigations-EmbryoSurvivalandEmergenceStudies.IdahoDep.Fish.GameCompletionRep.No.F-49-4-7.11pp.Bjornn,T.C.,M.A.Brusven,M.P.Molnau,J.H.Milligan,R.A.KLlamt,E.ChachoandC.Schaye.1977.TransportofGraniticSedimentinStreamsanditsEffectsonInsectsandFish.For.WildlifeandRangeExp.Stn.CompletionRep.WaterResour.Res.Inst.Proj.B-036-IDA.Univ.ofIdaho,Moscow.44pp.Bodaly,R.A.andR.E.Hecky.1979.Post-impcundmentIncreasesinFishMercuryLevelsintheSouthernIndianLakeReservoir,Manitoba.Fish.MarineServoManuscr.Rep.No.1531.DepartmentofFisheriesandEnvironment,Winnipeg,Manitoba,Canada.15pp.Bodaly,R.A.andR.E.Hecky.1982.ThePotentialforMercuryAccumulationinFishMuscleasaResult oftheProposedPeaceRiverSiteCReservoir.ReportpreparedbyCanadaDepartmentofFisheriesandOceansforBritishColumbiaUtilitiesCommission,Vancouver,BritishColumbia.Bodaly,R.A.,R.E.HeckyandR.J.P.Fudge.1984.IncreasesinFishMercuryLevelsinLakesFloodedbytheChurchillRiverDiversion,NorthernManitoba.Draftreport,FreshwaterInstitute,CanadaDepartmentofFisheriesandOceans,Winnipeg,Manitoba.22pp.Bovee,K.D.1978.ProbabilityofUseCriteriafortheFamilySalmonidae.FWS/OBS-78/07.CooperativeInstreamFlowServiceGroup,U.S.FishandWildlifeService,FortCollins,CO.Brannon,E.L.1972.Mechanismscontrollingmigrationofsockeyesalmonfry.Int.Pac.SalmonFish.Corum.Bull.21.Brett,J.R.1952.TemperaturetoleranceinyoungPacificsalmon,genusOncorhynchus.J.Fish.Res.BoardCan.9(6):265-323.Brett,J.R.1971.Energeticresponsesofsalmontotemperature:astudyofsomethermalrelationsinthephysiologyandfreshwaterecologyofsockeyesalmon.Am.Zool.11:99-113.Brett,J.R.1974.Tankexperimentsonthecultureofpan-sizesockeye(Oncorhynchusnerka)andpinksalmon(0.gorbuscha)usingenvironmentalcontrol.Aquaculture4:341-352.Bryant,M.D.1983.Theroleandmanagementofwoodydebrisinwestcoastsalmonidnurserystreams.NorthAm.J.Fish.Manage.3:322-330.Burgner,R.L.1962a.StudiesofredsalmonsmoltsfromtheWoodRiverLakes,Alaska,INS.Y.Koo(ed.),StudiesofAlaskaRedSalmon.Univ.ofWashingtonPress,Seattle.Burgner,R.L.1962b.SamplingredsalmonfrybylaketrapintheWoodRiverLakes,Alaska,INS.Y.Koo(ed.),StudiesofAlaskaRedSalmon.Univ.ofWashingtonPress,Seattle.Burrows,R.E.1963.Watertemperaturerequirementsformaximumproductivityofsalmon,pp.29-38.INE.B.Eldridge(ed.),WaterTemperature-Influences,Effects,andControl.Proc.,12thPacificNorthwestSymposiumonWaterPollutionResearch.U.S.PublicHealthService,Corvallis,OR.Bustard,D.R.andD.W.Narver.1975a.Aspectsofthewinterecologyofjuvenilecohosalmon(Oncorhynchuskisutch)andsteelheadtrout(Salmogairdneri).J.Fish.Res.BoardCan.32:667-680.Bustard,D.R.andD.W.Narver.1975b.Preferencesofjuvenilecohosalmon(Oncorhynchuskisutch)andcutthroattrout(Salmoclarki)relativetosimulatedalterationofwinterhabitat.J.Fish.Res.BoardCan.32:681-687.Chapman,D.W.,andT.C.Bjornn.1969.Distributionofsalmonidsinstreamswithspecialreferencetofoodandfeeding,pp.153-176.INT.G.Northcote(ed.),SymposiumonSalmonandTroutinStreams,H.R.MacMillanLecturesinFisheries.InstituteofFisheries,Univ.ofBritishColumbia,Vancouver.CookInletAquacultureAssociation(CIAA).1983a.EklutnaHatchery-1979IdeaBecomes1983Reality.CIAASmolts6:4-5.CookInletAquacultureAssociation(CIAA).1983b.Eklutnahatcherycompleteaseriesof"firsts."CIAASmolts7:1,7.1-69Bilton,H.T.1971.IdentificationofmajorBritishColumbiaandAlaskarunsofeven-yearandodd-yearpinksalmonfromscalecharacters.J.Fish.Res.BoardCan.29:295-301.Bjornn,T.C.1969.SalmonandSteelheadInvestigations-EmbryoSurvivalandEmergenceStudies.IdahoDep.Fish.GameCompletionRep.No.F-49-4-7.11pp.Bjornn,T.C.,M.A.Brusven,M.P.Molnau,J.H.Milligan,R.A.KLlamt,E.ChachoandC.Schaye.1977.TransportofGraniticSedimentinStreamsanditsEffectsonInsectsandFish.For.WildlifeandRangeExp.Stn.CompletionRep.WaterResour.Res.Inst.Proj.B-036-IDA.Univ.ofIdaho,Moscow.44pp.Bodaly,R.A.andR.E.Hecky.1979.Post-impcundmentIncreasesinFishMercuryLevelsintheSouthernIndianLakeReservoir,Manitoba.Fish.MarineServoManuscr.Rep.No.1531.DepartmentofFisheriesandEnvironment,Winnipeg,Manitoba,Canada.15pp.Bodaly,R.A.andR.E.Hecky.1982.ThePotentialforMercuryAccumulationinFishMuscleasaResult oftheProposedPeaceRiverSiteCReservoir.ReportpreparedbyCanadaDepartmentofFisheriesandOceansforBritishColumbiaUtilitiesCommission,Vancouver,BritishColumbia.Bodaly,R.A.,R.E.HeckyandR.J.P.Fudge.1984.IncreasesinFishMercuryLevelsinLakesFloodedbytheChurchillRiverDiversion,NorthernManitoba.Draftreport,FreshwaterInstitute,CanadaDepartmentofFisheriesandOceans,Winnipeg,Manitoba.22pp.Bovee,K.D.1978.ProbabilityofUseCriteriafortheFamilySalmonidae.FWS/OBS-78/07.CooperativeInstreamFlowServiceGroup,U.S.FishandWildlifeService,FortCollins,CO.Brannon,E.L.1972.Mechanismscontrollingmigrationofsockeyesalmonfry.Int.Pac.SalmonFish.Corum.Bull.21.Brett,J.R.1952.TemperaturetoleranceinyoungPacificsalmon,genusOncorhynchus.J.Fish.Res.BoardCan.9(6):265-323.Brett,J.R.1971.Energeticresponsesofsalmontotemperature:astudyofsomethermalrelationsinthephysiologyandfreshwaterecologyofsockeyesalmon.Am.Zool.11:99-113.Brett,J.R.1974.Tankexperimentsonthecultureofpan-sizesockeye(Oncorhynchusnerka)andpinksalmon(0.gorbuscha)usingenvironmentalcontrol.Aquaculture4:341-352.Bryant,M.D.1983.Theroleandmanagementofwoodydebrisinwestcoastsalmonidnurserystreams.NorthAm.J.Fish.Manage.3:322-330.Burgner,R.L.1962a.StudiesofredsalmonsmoltsfromtheWoodRiverLakes,Alaska,INS.Y.Koo(ed.),StudiesofAlaskaRedSalmon.Univ.ofWashingtonPress,Seattle.Burgner,R.L.1962b.SamplingredsalmonfrybylaketrapintheWoodRiverLakes,Alaska,INS.Y.Koo(ed.),StudiesofAlaskaRedSalmon.Univ.ofWashingtonPress,Seattle.Burrows,R.E.1963.Watertemperaturerequirementsformaximumproductivityofsalmon,pp.29-38.INE.B.Eldridge(ed.),WaterTemperature-Influences,Effects,andControl.Proc.,12thPacificNorthwestSymposiumonWaterPollutionResearch.U.S.PublicHealthService,Corvallis,OR.Bustard,D.R.andD.W.Narver.1975a.Aspectsofthewinterecologyofjuvenilecohosalmon(Oncorhynchuskisutch)andsteelheadtrout(Salmogairdneri).J.Fish.Res.BoardCan.32:667-680.Bustard,D.R.andD.W.Narver.1975b.Preferencesofjuvenilecohosalmon(Oncorhynchuskisutch)andcutthroattrout(Salmoclarki)relativetosimulatedalterationofwinterhabitat.J.Fish.Res.BoardCan.32:681-687.Chapman,D.W.,andT.C.Bjornn.1969.Distributionofsalmonidsinstreamswithspecialreferencetofoodandfeeding,pp.153-176.INT.G.Northcote(ed.),SymposiumonSalmonandTroutinStreams,H.R.MacMillanLecturesinFisheries.InstituteofFisheries,Univ.ofBritishColumbia,Vancouver.CookInletAquacultureAssociation(CIAA).1983a.EklutnaHatchery-1979IdeaBecomes1983Reality.CIAASmolts6:4-5.CookInletAquacultureAssociation(CIAA).1983b.Eklutnahatcherycompleteaseriesof"firsts."CIAASmolts7:1,7. 1-70CookInletRegionalPlanningTeam.1981.CookInletRegionalSalmonEnhancementPlan,1981-2000.CookInletAquacultureAssociation,Goldatna,AK.Cordone,A.J.andD.W.Kelley.1961.Theinfluenceofinorganicsedimentontheaquaticlifeofstreams.Calif.FishGame47:189-228.Coutant,C.C.1977.Compilationoftemperaturepreferencedata.J.Fish.Res.BoardCan.34:739-745.Coutant,C.C.,andD.L.DeAngelis.1983.Comparativetemperature-dependentgrowthratesoflargemouthandsmallmouthbassfry.Trans.Am.Fish.Soc.112:416-423.Oauble,D.O.,R.H.Gray,andT.L.Page.1980.ImportanceofinsectsandzooplanktoninthedietofO-AgechinooksalmonOncorhynchustshawytschainthecentralColumbiaRiver.NorthwestSci.54(4):253-258.Foerster,R.E.1954.Ontherelationofadultsockeyesalmon(Oncorhynchusnerka)returnstoknownsmoltseawardmigrations.J.Fish.Res.BoardCan.11:339-350.Foerster,R.E.1937.Therelationoftemperaturetotheseawardmigrationofyoungsockeyesalmon(Oncorhynchusnerka).J.Biol.BoardCan.3:421-438.Foster,D.1982.TheUtilizationofKingSalmonandtheAnnualRoundofResourceUsesinTyonek,Alaska.TechnicalPaperNo.27,AlaskaDepartmentofFishandGame,DivisionofSubsistence,Anchorage,AK.Fraley,J.J.,andP.J.Graham.1982.TheImpactofHungryHorseDamontheFisheryoftheFlatheadRiver-FinalReport.MontanaDepartmentofFish,WildlifeandParks,Kalispell,MT.Fredeen,F.G.H.1977.SomerecentchangesinblackflypopulationsintheSaskatchewanRiversysteminWesternCanadacoincidingwiththedevelopmentofreservoirs.Can.WaterResour.J.2(3-4):90-102.Friese,N.V.1975.PreauthorizationAssessmentofAnadromousFishPopulationsoftheUpperSusitnaRiverWatershedintheVicinityoftheProposedDevilCanyonHydroelectricProject.CookInletDataReportNo.75-2.AlaskaDepartmentofFishandGame,Anchorage,AK.Geen,G.H.1974.EffectsofhydroelectricdevelopmentinWesternCanadaonaquaticecosystems.J.Fish.Res.BoardCan.31:913-927.Gilhousen,P.1962.MarinefactorsaffectingthesurvivalofFraserRiverpinksalmon,pp.105-111.INN.J.Wilimovsky(ed.),SymposiumonPinkSalmon.H.R.MacMillanLecturesinFisheries.Univ.ofBritishColumbia,Vancouver.Grant,W.S.,G.B.Milner,P.KrasnowskiandF.M.Utter.1980.Useofbiochemicalgeneticvariantsforidentificationofsockeyesalmon(Oncorhynuchusnerka)stocksinCookInlet,Alaska.Can.J.Fish.Aquat.Sci.37:1236-1247.Grau,E.G.,W.W.Dickhoff,R.S.Nishioka,H.A.Bern,andL.C.Folmar.1981.Lunarphasingofthethyroxinesurgepreparatorytoseawardmigrationofsalmonidfish.Science211:607-609.Graybill,J.P.,R.L.Burgner,J.C.Gislason,P.E.Huffman,K.H.Wyman,R.G.Gibbons,K.W.Kurdo,Q.J.Stober,T.W.Fagnan,A.P.StaymanandD.M.Eggers.1979.AssessmentoftheReservoir-RelatedEffectsoftheSkagitProjectonDownstreamFisheryResourcesoftheSkagitRiver,Washington.FRI-UW-7905.FinalReportbyFisheriesResearchInstitute,Univ.ofWashington,orCityofSeattle,Washington.pp.602.Grimas,U.1961.TheBottomFaunaofNaturalandImpoundedLakesinNorthernSweden(AnkarvattnetandBlasjon).Rep.No.42:183-237.InstituteofFreshwaterResearch,Drottningholm,Sweden.Grimas,U.andN.A.Nilsson.1965.OntheFoodChaininSomeNorthSwedishRiverReservoirs.Rep.No.46:31-48.InstituteofFreshwaterResearch,Drottningholm,Sweden.Grogan,R.L.1983.Subject:SusitnaHydroelectricProjectApplication.LettertoMr.LarryCrawford,AlaskaPowerAuthority,datedNovember18,1983,fromtheOfficeoftheGovernor,OfficeofManagementandBudget,DivisionofGovernmentalCoordination,Juneau,AK.1-70CookInletRegionalPlanningTeam.1981.CookInletRegionalSalmonEnhancementPlan,1981-2000.CookInletAquacultureAssociation,Goldatna,AK.Cordone,A.J.andD.W.Kelley.1961.Theinfluenceofinorganicsedimentontheaquaticlifeofstreams.Calif.FishGame47:189-228.Coutant,C.C.1977.Compilationoftemperaturepreferencedata.J.Fish.Res.BoardCan.34:739-745.Coutant,C.C.,andD.L.DeAngelis.1983.Comparativetemperature-dependentgrowthratesoflargemouthandsmallmouthbassfry.Trans.Am.Fish.Soc.112:416-423.Oauble,D.O.,R.H.Gray,andT.L.Page.1980.ImportanceofinsectsandzooplanktoninthedietofO-AgechinooksalmonOncorhynchustshawytschainthecentralColumbiaRiver.NorthwestSci.54(4):253-258.Foerster,R.E.1954.Ontherelationofadultsockeyesalmon(Oncorhynchusnerka)returnstoknownsmoltseawardmigrations.J.Fish.Res.BoardCan.11:339-350.Foerster,R.E.1937.Therelationoftemperaturetotheseawardmigrationofyoungsockeyesalmon(Oncorhynchusnerka).J.Biol.BoardCan.3:421-438.Foster,D.1982.TheUtilizationofKingSalmonandtheAnnualRoundofResourceUsesinTyonek,Alaska.TechnicalPaperNo.27,AlaskaDepartmentofFishandGame,DivisionofSubsistence,Anchorage,AK.Fraley,J.J.,andP.J.Graham.1982.TheImpactofHungryHorseDamontheFisheryoftheFlatheadRiver-FinalReport.MontanaDepartmentofFish,WildlifeandParks,Kalispell,MT.Fredeen,F.G.H.1977.SomerecentchangesinblackflypopulationsintheSaskatchewanRiversysteminWesternCanadacoincidingwiththedevelopmentofreservoirs.Can.WaterResour.J.2(3-4):90-102.Friese,N.V.1975.PreauthorizationAssessmentofAnadromousFishPopulationsoftheUpperSusitnaRiverWatershedintheVicinityoftheProposedDevilCanyonHydroelectricProject.CookInletDataReportNo.75-2.AlaskaDepartmentofFishandGame,Anchorage,AK.Geen,G.H.1974.EffectsofhydroelectricdevelopmentinWesternCanadaonaquaticecosystems.J.Fish.Res.BoardCan.31:913-927.Gilhousen,P.1962.MarinefactorsaffectingthesurvivalofFraserRiverpinksalmon,pp.105-111.INN.J.Wilimovsky(ed.),SymposiumonPinkSalmon.H.R.MacMillanLecturesinFisheries.Univ.ofBritishColumbia,Vancouver.Grant,W.S.,G.B.Milner,P.KrasnowskiandF.M.Utter.1980.Useofbiochemicalgeneticvariantsforidentificationofsockeyesalmon(Oncorhynuchusnerka)stocksinCookInlet,Alaska.Can.J.Fish.Aquat.Sci.37:1236-1247.Grau,E.G.,W.W.Dickhoff,R.S.Nishioka,H.A.Bern,andL.C.Folmar.1981.Lunarphasingofthethyroxinesurgepreparatorytoseawardmigrationofsalmonidfish.Science211:607-609.Graybill,J.P.,R.L.Burgner,J.C.Gislason,P.E.Huffman,K.H.Wyman,R.G.Gibbons,K.W.Kurdo,Q.J.Stober,T.W.Fagnan,A.P.StaymanandD.M.Eggers.1979.AssessmentoftheReservoir-RelatedEffectsoftheSkagitProjectonDownstreamFisheryResourcesoftheSkagitRiver,Washington.FRI-UW-7905.FinalReportbyFisheriesResearchInstitute,Univ.ofWashington,orCityofSeattle,Washington.pp.602.Grimas,U.1961.TheBottomFaunaofNaturalandImpoundedLakesinNorthernSweden(AnkarvattnetandBlasjon).Rep.No.42:183-237.InstituteofFreshwaterResearch,Drottningholm,Sweden.Grimas,U.andN.A.Nilsson.1965.OntheFoodChaininSomeNorthSwedishRiverReservoirs.Rep.No.46:31-48.InstituteofFreshwaterResearch,Drottningholm,Sweden.Grogan,R.L.1983.Subject:SusitnaHydroelectricProjectApplication.LettertoMr.LarryCrawford,AlaskaPowerAuthority,datedNovember18,1983,fromtheOfficeoftheGovernor,OfficeofManagementandBudget,DivisionofGovernmentalCoordination,Juneau,AK. 1-71Groot,C.1965.Ontheorientationofyoungsockeyesalmon(Oncorhynchusnerka)duringtheirseawardmigrationoutoflakes.BehaviourSupp1.14.Hale,S.S.1981a.FreshwaterHabitatRelationships,ThreespineStickleback(Gasterosteusaculeatus).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.46pp.Hale,S.S.1981b.FreshwaterHabitatRelationships,ChumSalmon(Oncorhynchusketa).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.93pp.Hale,S.S.1981c.FreshwaterHabitatRelationships,RoundWhitefish(Prosopiumcylindraceum).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.18pp.Hanson,M.andT.Linstrom.1979.Suorva-enregleradsjodarfiskeninteharfordvargats(Suorva:Alakereservoirwithcharandwhitefishofgoodsize).InformationBull.No.4.InstituteofFreshwaterResearch,Drottningho1m,Sweden.Hartman,G.F.1965.Theroleofbehaviorintheecologyandinteractionofunderyear1ingcohosalmon(Oncorhynchuskisutch)andsteelheadtrout(Sa1mogairdneri).J.Fish.Res.BoardCan.22:1035-1081.Hartman,W.L.1971.Alaska'sFisheryResources.TheSockeyeSalmon.FisheryLeaflet636.U.S.DepartmentofCommerce,Washington,DC.Hartman,W.L.,W.R.HeardandB.Drucker.1967.Migratorybehaviorofsockeyesalmonfryandsmolts.J.Fish.Res.BoardCan.24:2069-2099.Heard,W.R.1966.ObservationsonLampreysintheNaknekRiverSystemofSouthwestAlaska.,Vol.2.(ascitedintheapplication).Heggberget,T.G.(inpress).Populationsofpresmo1tAtlanticsalmon(Sa1mosa1arL.)andbrowntrout(SalmotruttaL.)beforeandafterhydroelectricdevelopmentandbuildingofweirsintheRiverSkjoma,NorthNorway.Proc.SecondInt.Symp.onRegulatedStreams,Oslo,Norway.1982.Hill,D.M.1972.StreamFaunalRecoveryafterManganeseStripMineReclamation.PhDDissertation.VirginiaPolytechnicInstituteandStateUniv.,Blacksburg.Hoar,W.S.1951.Thebehaviorofchumpinkandcohosalmoninrelationtotheirseawardmigration.J.Fish.Res.BoardCan.8:241-263.Huntsman,A.G.1948.Fertilityandfertilizationofstreams.J.Fish.Res.BoardCan.7:248-253.Hutchinson,G.E.1953.Theconceptofpatterninecology.Proc.Nat.Acad.Sci.105:1-12.Hutchinson,G.E.1961.Theparadoxofplankton.Am.Nat.95:137-145.Hutchinson,G.E.1975.VariationsonathemebyRobertMacArthur,pp.445-459.INM.L.CodyandJ.M.Diamond(eds.),EcologyandEvolutionofCommunities.BelknapPress,HarvardUniversity,Cambridge,MA.Hynes,H.B.N.1970.Theecologyofrunningwater.Univ.ofTorontoPress.555pp.ISACF.1980.ProceedingsoftheFirstISACFWorkshoponArcticchar,1980.ISACFInformationSeriesNo.1.InstituteofFreshwaterResearch,Drottningholm,Sweden.Iwamoto,R.N.,E.O.Sa10,M.A.MadejandR.L.McComas.1978.SedimentandWaterQuality:AReviewoftheLiteratureIncludingaSuggestedApproachforWaterQualityCriteria.EPA910/9-78-048,Univ.ofWashington,FisheriesResearchInstitute,Seattle,WA.Kanidyev,A.N.,G.M.KostyuninandS.A.Salmin.1970.HatcherypropagationofthepinksalmonandchumsalmonsasameansofincreasingthesalmonstocksofSakhalin.J.Ichthyo1.(EnglishtranslationofVoprosyIkhtio10gii)10:249-259.Keenleyside,M.H.A.andW.S.Hoar.1955.Effectsoftemperatureontheresponsesofyoungsalmontowatercurrent.Behaviour7:77-87.Koksvik,J.I.1977.Ferskvannsbiologiskeoghydrografiskeundersoke1seriSa1tfje11-Svartisomradet.DelII.Sa1tdalsvassdraget.K.NorskeVidensk.Selsk.Mus.Rapp.Zool.Ser.1977-16.1-71Groot,C.1965.Ontheorientationofyoungsockeyesalmon(Oncorhynchusnerka)duringtheirseawardmigrationoutoflakes.BehaviourSupp1.14.Hale,S.S.1981a.FreshwaterHabitatRelationships,ThreespineStickleback(Gasterosteusaculeatus).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.46pp.Hale,S.S.1981b.FreshwaterHabitatRelationships,ChumSalmon(Oncorhynchusketa).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.93pp.Hale,S.S.1981c.FreshwaterHabitatRelationships,RoundWhitefish(Prosopiumcylindraceum).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.18pp.Hanson,M.andT.Linstrom.1979.Suorva-enregleradsjodarfiskeninteharfordvargats(Suorva:Alakereservoirwithcharandwhitefishofgoodsize).InformationBull.No.4.InstituteofFreshwaterResearch,Drottningho1m,Sweden.Hartman,G.F.1965.Theroleofbehaviorintheecologyandinteractionofunderyear1ingcohosalmon(Oncorhynchuskisutch)andsteelheadtrout(Sa1mogairdneri).J.Fish.Res.BoardCan.22:1035-1081.Hartman,W.L.1971.Alaska'sFisheryResources.TheSockeyeSalmon.FisheryLeaflet636.U.S.DepartmentofCommerce,Washington,DC.Hartman,W.L.,W.R.HeardandB.Drucker.1967.Migratorybehaviorofsockeyesalmonfryandsmolts.J.Fish.Res.BoardCan.24:2069-2099.Heard,W.R.1966.ObservationsonLampreysintheNaknekRiverSystemofSouthwestAlaska.,Vol.2.(ascitedintheapplication).Heggberget,T.G.(inpress).Populationsofpresmo1tAtlanticsalmon(Sa1mosa1arL.)andbrowntrout(SalmotruttaL.)beforeandafterhydroelectricdevelopmentandbuildingofweirsintheRiverSkjoma,NorthNorway.Proc.SecondInt.Symp.onRegulatedStreams,Oslo,Norway.1982.Hill,D.M.1972.StreamFaunalRecoveryafterManganeseStripMineReclamation.PhDDissertation.VirginiaPolytechnicInstituteandStateUniv.,Blacksburg.Hoar,W.S.1951.Thebehaviorofchumpinkandcohosalmoninrelationtotheirseawardmigration.J.Fish.Res.BoardCan.8:241-263.Huntsman,A.G.1948.Fertilityandfertilizationofstreams.J.Fish.Res.BoardCan.7:248-253.Hutchinson,G.E.1953.Theconceptofpatterninecology.Proc.Nat.Acad.Sci.105:1-12.Hutchinson,G.E.1961.Theparadoxofplankton.Am.Nat.95:137-145.Hutchinson,G.E.1975.VariationsonathemebyRobertMacArthur,pp.445-459.INM.L.CodyandJ.M.Diamond(eds.),EcologyandEvolutionofCommunities.BelknapPress,HarvardUniversity,Cambridge,MA.Hynes,H.B.N.1970.Theecologyofrunningwater.Univ.ofTorontoPress.555pp.ISACF.1980.ProceedingsoftheFirstISACFWorkshoponArcticchar,1980.ISACFInformationSeriesNo.1.InstituteofFreshwaterResearch,Drottningholm,Sweden.Iwamoto,R.N.,E.O.Sa10,M.A.MadejandR.L.McComas.1978.SedimentandWaterQuality:AReviewoftheLiteratureIncludingaSuggestedApproachforWaterQualityCriteria.EPA910/9-78-048,Univ.ofWashington,FisheriesResearchInstitute,Seattle,WA.Kanidyev,A.N.,G.M.KostyuninandS.A.Salmin.1970.HatcherypropagationofthepinksalmonandchumsalmonsasameansofincreasingthesalmonstocksofSakhalin.J.Ichthyo1.(EnglishtranslationofVoprosyIkhtio10gii)10:249-259.Keenleyside,M.H.A.andW.S.Hoar.1955.Effectsoftemperatureontheresponsesofyoungsalmontowatercurrent.Behaviour7:77-87.Koksvik,J.I.1977.Ferskvannsbiologiskeoghydrografiskeundersoke1seriSa1tfje11-Svartisomradet.DelII.Sa1tdalsvassdraget.K.NorskeVidensk.Selsk.Mus.Rapp.Zool.Ser.1977-16. 1-72McClane,A.J.1965.McClane'sStandardFishingEncyclopedia.Holt,Rinehart,andWinston,NewYork.1072pp.LaPerrier,J.andR.Carlson.1973.ThermalTolerancesofInteriorAlaskaArcticGrayling.ReportNo.IWR-46.InstituteofWaterResources,Univ.ofAlaska,Fairbanks.36pp.1966.InfluencesoftemperatureontheefficiencyofgrowthofsalmonidNature212(5065):957-959.Marr,D.H.A.embryos.Morgan,MoD.,S.T.ThrelkeldandC.R.Goldman.1978.Impactoftheintroductionofkokanee(Oncorhynchusnerka)andoppossumshrimp(~ysisrelicta)onasubalpinelake.J.Fish.Res.BoardCan~12):1572-l579.Mills,M.J.1981.AlaskaStatewideSportFishHarvestStudies,1980Data.F-9-l3,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestorationandAnadromousFishStudies,Vol.22.Juneau,AK.Mills,M.J.1980.AlaskaStatewideSportFishHarvestStUdies,1980.F-9-l2,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestoration,Vol.21.Juneau,AK.Mills,M.J.1982.AlaskaStatewideSportFishHarvestStudies.F-9-l4,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestoration,Vol.23.Juneau,AK.McNeil,WilliamJ.andJackE.Bailey.1975.SalmonRancher'sManual.Nat.Marine.FisheriesServiceNorthwestFisheriesCenter,AukeBayFisheriesLaboratory,AukeBay,AK.95pp.McMullin,S.L.andP.J.Graham.1981.TheImpactofHungryHorseDamontheKokaneeFisheryoftheFlatheadRiver.MontanaDepartmentofFish,WildlifeandParks,Kalispell,MT.McLean,R.F.andK.S.Delaney.1978.Alaska'sFisheriesAtlas,Vol.II.AlaskaDepartmentofFishandGame,Anchorage,AK.Levanidov,V.Ya.1964.TherelationshipbetweenthesizeoffingerlingAmurautumnchum(Oncorhynchusketainfrasp.autumnalisBerg)andtheirsurvival.J.Ichthyol.(EnglishtranslationofVoprosyIkhtiologii)4:658-663.Major,R.L.andJ.L.Mighell.1966.InfluenceofRockyReachDamandthetemperatureoftheOkanoghanRiverontheupstreammigrationofsockeyesalmon.U.S.Fish.Wildl.ServoFish.Bull.66(1):131-147.McPhail,J.D.andC.C.Lindsey.1970.FreshwaterfishesofNorthwesternCanadaandAlaska.Fish.Res.BoardCan.Bull.173,Ottawa.381pp.Mills,M.J.1979.AlaskaStatewideSportFishHarvestStudies,1979.F-9-11,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestoration,Vol.20.Juneau,AK.McCuddin,M.E.1977.SurvivalofSalmonandTroutEmbryosandFryinGravelSandMixtures.Univ.ofIdaho,Moscow.30pp.McNeil,W.J.1968.Survivalofpinkandchumsalmoneggsandalevins,pp.101-117.INT.G.Northcote(ed.),SymposiumonSalmonandTroutinStreams.Univ.ofBritishColumbia,Vancouver.McGregor,A.J.1983.ABiochemicalGeneticAnalysisofPinkSalmon(Oncorhynchusgorbuscha)fromSelectedStreamsinNorthernSoutheastAlaska.InformationalLeafletNo.213.AlaskaofFishandGame,Anchorage,AK.Krueger,S.W.1981a.FreshwaterHabitatRelationships,PinkSalmon(Oncorhynchusgorbuscha).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.40pp.Krueger,S.W.1981b.FreshwaterHabitatRelationships,DollyVardenChar[Salvelinusmalnea(Walbaum)J.AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.38pp.Krueger,S.W.1981c.FreshwaterHabitatRelationships,ArcticGrayling(Thymallusarcticus).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.65pp.Kruse,T.1959.GraylingofGrebeLake,YellowstoneNationalPark,Wyoming.U.S.FishWildl.ServoFish.Bull.59:305-351.1-72McClane,A.J.1965.McClane'sStandardFishingEncyclopedia.Holt,Rinehart,andWinston,NewYork.1072pp.LaPerrier,J.andR.Carlson.1973.ThermalTolerancesofInteriorAlaskaArcticGrayling.ReportNo.IWR-46.InstituteofWaterResources,Univ.ofAlaska,Fairbanks.36pp.1966.InfluencesoftemperatureontheefficiencyofgrowthofsalmonidNature212(5065):957-959.Marr,D.H.A.embryos.Morgan,MoD.,S.T.ThrelkeldandC.R.Goldman.1978.Impactoftheintroductionofkokanee(Oncorhynchusnerka)andoppossumshrimp(~ysisrelicta)onasubalpinelake.J.Fish.Res.BoardCan~12):1572-l579.Mills,M.J.1981.AlaskaStatewideSportFishHarvestStudies,1980Data.F-9-l3,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestorationandAnadromousFishStudies,Vol.22.Juneau,AK.Mills,M.J.1980.AlaskaStatewideSportFishHarvestStUdies,1980.F-9-l2,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestoration,Vol.21.Juneau,AK.Mills,M.J.1982.AlaskaStatewideSportFishHarvestStudies.F-9-l4,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestoration,Vol.23.Juneau,AK.McNeil,WilliamJ.andJackE.Bailey.1975.SalmonRancher'sManual.Nat.Marine.FisheriesServiceNorthwestFisheriesCenter,AukeBayFisheriesLaboratory,AukeBay,AK.95pp.McMullin,S.L.andP.J.Graham.1981.TheImpactofHungryHorseDamontheKokaneeFisheryoftheFlatheadRiver.MontanaDepartmentofFish,WildlifeandParks,Kalispell,MT.McLean,R.F.andK.S.Delaney.1978.Alaska'sFisheriesAtlas,Vol.II.AlaskaDepartmentofFishandGame,Anchorage,AK.Levanidov,V.Ya.1964.TherelationshipbetweenthesizeoffingerlingAmurautumnchum(Oncorhynchusketainfrasp.autumnalisBerg)andtheirsurvival.J.Ichthyol.(EnglishtranslationofVoprosyIkhtiologii)4:658-663.Major,R.L.andJ.L.Mighell.1966.InfluenceofRockyReachDamandthetemperatureoftheOkanoghanRiverontheupstreammigrationofsockeyesalmon.U.S.Fish.Wildl.ServoFish.Bull.66(1):131-147.McPhail,J.D.andC.C.Lindsey.1970.FreshwaterfishesofNorthwesternCanadaandAlaska.Fish.Res.BoardCan.Bull.173,Ottawa.381pp.Mills,M.J.1979.AlaskaStatewideSportFishHarvestStudies,1979.F-9-11,SW-I.AlaskaDepartmentofFishandGame,FederalAidinFishRestoration,Vol.20.Juneau,AK.McCuddin,M.E.1977.SurvivalofSalmonandTroutEmbryosandFryinGravelSandMixtures.Univ.ofIdaho,Moscow.30pp.McNeil,W.J.1968.Survivalofpinkandchumsalmoneggsandalevins,pp.101-117.INT.G.Northcote(ed.),SymposiumonSalmonandTroutinStreams.Univ.ofBritishColumbia,Vancouver.McGregor,A.J.1983.ABiochemicalGeneticAnalysisofPinkSalmon(Oncorhynchusgorbuscha)fromSelectedStreamsinNorthernSoutheastAlaska.InformationalLeafletNo.213.AlaskaofFishandGame,Anchorage,AK.Krueger,S.W.1981a.FreshwaterHabitatRelationships,PinkSalmon(Oncorhynchusgorbuscha).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.40pp.Krueger,S.W.1981b.FreshwaterHabitatRelationships,DollyVardenChar[Salvelinusmalnea(Walbaum)J.AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.38pp.Krueger,S.W.1981c.FreshwaterHabitatRelationships,ArcticGrayling(Thymallusarcticus).AlaskaDepartmentofFishandGame,HabitatDivision,Anchorage,AK.65pp.Kruse,T.1959.GraylingofGrebeLake,YellowstoneNationalPark,Wyoming.U.S.FishWildl.ServoFish.Bull.59:305-351. 1-73Morrow,J.E.1980.ThefreshwaterfishesofAlaska.AlaskaNorthwestPubl.Co.,Anchorage,AK.248pp.Murphy,M.L.,C.P.HawkinsandN.H.Anderson.1981.Effectsofcanopymodificationandaccumulatedsedimentonstreamcommunities.Trans.Am.Fish.Soc.110:469-478.NationalAcademyofSciences/NationalAcademyofEngineering.1973.WaterQualityCriteria-1972.EPA.R.73.033.U.S.EnvironmentalProtectionAgency,Washington,DC.Noggle,C.C.1978.Behavioral,PhysiologicalandLethalEffectsofSuspendedSedimentonJuvenileSalmonids.MSThesis.Univ.ofWashington,Seattle.87pp.Northcote,T.G.1972.KootnayLake:man'seffectonthesalmonidcommunity.J.Fish.Res.BoardCan.29(6):861-865.Okazaki,T.1981.Geographicaldistributionofallelicvariationsofenzymesinchumsalmon,Oncorhynchusketa,populationsofNorthAmerica.Bull.Jpn.Soc.Sci.Fish.47:507-514.Olson,P.A.,R.E.NakataniandT.Meekin.YoungofColumbiaRiverFallChinook.Richland,WA.1970.EffectsofThermalIncrementsonEggsandBNWL-1538.Battelle,PacificNorthwestLaboratory,Parametrix,Inc.,D.Chapman,andT.Welsh.1979.VernitaBarsspawningSurvey,1978-79.Document79-1221-36F.GrantCountyPublicUtilityDistrict,Ephrata,WA.Patrick,R.1975.Streamcommunities,pp.445-459.INM.L.CodyandJ.M.Diamond(eds.),EcologyandEvolutionofCommunities.BelknapPress,HarvardUniv.,Cambridge,MA.Phillips,R.W.,R.L.Lantz,E.W.ClaireandJ.R.Moving.1975.Someeffectsofgravelmixturesonemergenceofcohosalmonandsteelheadtroutfry.Trans.Am.Fish.Soc.104(3):461-466.Phinney,L.A.1974.FurtherObservationsofJuvenileSalmonStrandingsintheSkagitRiver,March1973.WashingtonDepartmentofFisheries,Olympia,WA.34pp.Piper,R.G.,I.B.McElwain,L.E.Orme,J.P.McCrasen,L.G.FowlerandJ.R.Leonard.1982.FishHatcheryManagement.U.S.FishandWildlifeService,Washington,DC.Rosenberg,D.andA.P.Wiens.1978.EffectofsedimentonmacrobenthicinvertebratesinaNorthernCanadianRiver.WaterRes.12:753-763.Scott,W.B.andE.J.Crossman.1973.FreshwaterFishesofCanada.Fish.Res.BoardCan.Bull.184.Ottawa.966pp.Seymour,A.H.1956.EffectsofTemperatureonYoungChinookSalmon.PhDDissertation,Univ.ofWashington,Seattle.127pp.Shaw,P.A.andJ.A.Maga.1943.Theeffectofminingsiltonyieldoffryfromsalmonspawningbeds.Calif.FishGame29(1):29-41.Shuter,B.J.,J.A.MacLean,F.E.J.FryandH.A.Regier.1980.Stochasticsimulationoftemperatureeffectsonfirst-yearsurvivalofsmallmouthbass.Trans.Am.Fish.Soc.109:1-34.Sorenson,D.L.,M.M.McCarthy,E.J.Middlebrooks,andD.B.Parcella.1977.SuspendedandDissolvedSolidsEffectsonFreshwaterBiota:AReview.EPA-600/3-77-042.Ecol.Res.Series.EnvironmentalProtectionAgency,Washington,DC.64pp.Spence,J.A.andH.B.N.Hynes.1971a.Differencesinbenthosupstreamanddownstreamofanimpoundment.J.FishRes.BoardCan.28:35-43.Spence,J.A.andH.B.N.Hynes.1971b.Differencesinfishpopulationsupstreamanddownstreamofamainstreamimpoundment.J.Fish.Res.BoardCan.28:45-46.SportFishingInstitute.1983.PendOreilleLakeKokaneeRestorationProgram.SFIBulletinNo.344:7.Stillwell,F.P.,J.K.Atkins,M.D.Evenson,R.D.Ewing,andJ.J.Martin.1977.DeterminationofSalmonidEggMortalityResultingfromClosureofLostCreenDam,September1,1976-April30,1977.InformationReportSeries,Fisheries77-9.OregonDepartmentofFishandWildlife,ResearchSection,Corvallis,OR.1-73Morrow,J.E.1980.ThefreshwaterfishesofAlaska.AlaskaNorthwestPubl.Co.,Anchorage,AK.248pp.Murphy,M.L.,C.P.HawkinsandN.H.Anderson.1981.Effectsofcanopymodificationandaccumulatedsedimentonstreamcommunities.Trans.Am.Fish.Soc.110:469-478.NationalAcademyofSciences/NationalAcademyofEngineering.1973.WaterQualityCriteria-1972.EPA.R.73.033.U.S.EnvironmentalProtectionAgency,Washington,DC.Noggle,C.C.1978.Behavioral,PhysiologicalandLethalEffectsofSuspendedSedimentonJuvenileSalmonids.MSThesis.Univ.ofWashington,Seattle.87pp.Northcote,T.G.1972.KootnayLake:man'seffectonthesalmonidcommunity.J.Fish.Res.BoardCan.29(6):861-865.Okazaki,T.1981.Geographicaldistributionofallelicvariationsofenzymesinchumsalmon,Oncorhynchusketa,populationsofNorthAmerica.Bull.Jpn.Soc.Sci.Fish.47:507-514.Olson,P.A.,R.E.NakataniandT.Meekin.YoungofColumbiaRiverFallChinook.Richland,WA.1970.EffectsofThermalIncrementsonEggsandBNWL-1538.Battelle,PacificNorthwestLaboratory,Parametrix,Inc.,D.Chapman,andT.Welsh.1979.VernitaBarsspawningSurvey,1978-79.Document79-1221-36F.GrantCountyPublicUtilityDistrict,Ephrata,WA.Patrick,R.1975.Streamcommunities,pp.445-459.INM.L.CodyandJ.M.Diamond(eds.),EcologyandEvolutionofCommunities.BelknapPress,HarvardUniv.,Cambridge,MA.Phillips,R.W.,R.L.Lantz,E.W.ClaireandJ.R.Moving.1975.Someeffectsofgravelmixturesonemergenceofcohosalmonandsteelheadtroutfry.Trans.Am.Fish.Soc.104(3):461-466.Phinney,L.A.1974.FurtherObservationsofJuvenileSalmonStrandingsintheSkagitRiver,March1973.WashingtonDepartmentofFisheries,Olympia,WA.34pp.Piper,R.G.,I.B.McElwain,L.E.Orme,J.P.McCrasen,L.G.FowlerandJ.R.Leonard.1982.FishHatcheryManagement.U.S.FishandWildlifeService,Washington,DC.Rosenberg,D.andA.P.Wiens.1978.EffectofsedimentonmacrobenthicinvertebratesinaNorthernCanadianRiver.WaterRes.12:753-763.Scott,W.B.andE.J.Crossman.1973.FreshwaterFishesofCanada.Fish.Res.BoardCan.Bull.184.Ottawa.966pp.Seymour,A.H.1956.EffectsofTemperatureonYoungChinookSalmon.PhDDissertation,Univ.ofWashington,Seattle.127pp.Shaw,P.A.andJ.A.Maga.1943.Theeffectofminingsiltonyieldoffryfromsalmonspawningbeds.Calif.FishGame29(1):29-41.Shuter,B.J.,J.A.MacLean,F.E.J.FryandH.A.Regier.1980.Stochasticsimulationoftemperatureeffectsonfirst-yearsurvivalofsmallmouthbass.Trans.Am.Fish.Soc.109:1-34.Sorenson,D.L.,M.M.McCarthy,E.J.Middlebrooks,andD.B.Parcella.1977.SuspendedandDissolvedSolidsEffectsonFreshwaterBiota:AReview.EPA-600/3-77-042.Ecol.Res.Series.EnvironmentalProtectionAgency,Washington,DC.64pp.Spence,J.A.andH.B.N.Hynes.1971a.Differencesinbenthosupstreamanddownstreamofanimpoundment.J.FishRes.BoardCan.28:35-43.Spence,J.A.andH.B.N.Hynes.1971b.Differencesinfishpopulationsupstreamanddownstreamofamainstreamimpoundment.J.Fish.Res.BoardCan.28:45-46.SportFishingInstitute.1983.PendOreilleLakeKokaneeRestorationProgram.SFIBulletinNo.344:7.Stillwell,F.P.,J.K.Atkins,M.D.Evenson,R.D.Ewing,andJ.J.Martin.1977.DeterminationofSalmonidEggMortalityResultingfromClosureofLostCreenDam,September1,1976-April30,1977.InformationReportSeries,Fisheries77-9.OregonDepartmentofFishandWildlife,ResearchSection,Corvallis,OR. 1-74Stober.Q.J••R.E.MaritaandA.J.Hama1ainen.1978.InstreamFlowandtheReproductiveEfficiencyofSockeyeSalmon.FisheriesResearchInstitute.Unov.ofWashington.Seattle.124pp.Tack.S.1973.Distribution.AbundanceandNaturalHistoryoftheArcticGraylingintheTananaRiverDrainage.F-9-6.AlaskaDepartmentofFishandGame.FederalAidinFishRestoration.AnnualReportofProgress.1972-1973.Vol.14.34pp.Tappe1.P.O.1981.ANewMethodofRelatingSpawningGravelSizeCompositiontoSa1monidEmbryoSurvival.MSThesis.Univ.ofIdaho.Moscow.Taylor.S.G.1980.Marinesurvivalofpinksalmonfryfromearlyandlatespawners.Trans.Am.Fish.Soc.109:79-82.ThompsonJ.S.1970.TheEffectofWaterFlowRegulationatGorgeDamonStrandingofSalmonFryintheSkagitRiver.1969-1970.Supp1.Prog.Rep••PowerDamStudies.ManagementandResearchDivision.WashingtonDepartmentofFish.Olympia.WA.46pp.Thompson.K.1972.Determiningstreamflowsforfi?hlife.pp.31-50.INProceedings.InstreamFlowRequirementWorkshop.PacificNorthwestRiverBasinCommission.Vancouver.WA.Trihey.E.W.1982.1982WinterTemperatureStudy.OpenfilereportforAcresAmerican.Inc••Buffalo.NY.Trihey.E.W.1983.PreliminaryAssessmentofAccessbySpawningSalmonintoPortageCreekandIndianRiver.PreparedforAlaskaPowerAuthority.Anchorage.AK.63pp.plusappendix.Vernon.E.H.1958.AnExaminationofFactorsAffectingtheAbundanceofPinkSalmonintheFraserRiver.Int.Pac.SalmonFish.Comm.Prog.Rep.No.5.NewWestminister.BritishColumbia.Wangaard.D.B.andC.V.Burger.1983.EffectsofVariousWaterTemperatureRegimesontheEggandA1evinIncubationofSusitnaRiverChumandSockeyeSalmon.U.S.DepartmentofInterior.FishandWildlifeService.NationalFisheryResearchCenter.AlaskaFieldStation.Anchorage.AK.43pp.Ward.J.V.1976.Effectsofflowpatternsbelowlargedamsonstreambenthos:areview.pp.235-253.INJ.F.OrsbornandC.H.Allman(eds.).InstreamFlowNeeds.AmericanFisheriesSociety.Bethesda.MD.Ward.J.andJ.A.Stanford(eds.).1979.TheEcologyofRegulatedStreams.PlenumPress.NewYork.pp.398.Welch.S.1952.Limnology.2ndrd.McGrawHillBookCompany.Inc••NewYork.538pp.Wilson.W.J••E.W.Trihey.J.E.Baldridge.C.D.Evans.J.G.ThieleandD.E.Trudgen.1981.AnAssessmentofEnvironmentalEffectsofConstructionandOperationoftheProposedTerrorLakeHydroelectricFacility.Kodiak.Alaska.InstreamFlowStudies.Univ.ofAlaska.ArcticEnvironmentalInformationandDataCenter.Anchorage.AK.Witty.K.andK.Thompson.1974.Fishstrandingsurveys.pp.113-120.INK.BayhaandC.Koski(eds.).AnatomyofaRiver.PacificNorthwestRiverBasinsCommission.Vancouver.WA.Wojcik.F.1954.SpawninghabitsofgraylingininteriorAlaska.ReportNo.2bytheAlaskaGameCommission.Juneau.AK.fortheU.S.DepartmentoftheInterior,FishandWildlifeService,Washington,DC.Wojcik.F.1955.LifehistoryandmanagementofthegraylingininteriorAlaska.MSThesis.Univ.ofAlaska.Fairbanks.54pp.1-74Stober.Q.J••R.E.MaritaandA.J.Hama1ainen.1978.InstreamFlowandtheReproductiveEfficiencyofSockeyeSalmon.FisheriesResearchInstitute.Unov.ofWashington.Seattle.124pp.Tack.S.1973.Distribution.AbundanceandNaturalHistoryoftheArcticGraylingintheTananaRiverDrainage.F-9-6.AlaskaDepartmentofFishandGame.FederalAidinFishRestoration.AnnualReportofProgress.1972-1973.Vol.14.34pp.Tappe1.P.O.1981.ANewMethodofRelatingSpawningGravelSizeCompositiontoSa1monidEmbryoSurvival.MSThesis.Univ.ofIdaho.Moscow.Taylor.S.G.1980.Marinesurvivalofpinksalmonfryfromearlyandlatespawners.Trans.Am.Fish.Soc.109:79-82.ThompsonJ.S.1970.TheEffectofWaterFlowRegulationatGorgeDamonStrandingofSalmonFryintheSkagitRiver.1969-1970.Supp1.Prog.Rep••PowerDamStudies.ManagementandResearchDivision.WashingtonDepartmentofFish.Olympia.WA.46pp.Thompson.K.1972.Determiningstreamflowsforfi?hlife.pp.31-50.INProceedings.InstreamFlowRequirementWorkshop.PacificNorthwestRiverBasinCommission.Vancouver.WA.Trihey.E.W.1982.1982WinterTemperatureStudy.OpenfilereportforAcresAmerican.Inc••Buffalo.NY.Trihey.E.W.1983.PreliminaryAssessmentofAccessbySpawningSalmonintoPortageCreekandIndianRiver.PreparedforAlaskaPowerAuthority.Anchorage.AK.63pp.plusappendix.Vernon.E.H.1958.AnExaminationofFactorsAffectingtheAbundanceofPinkSalmonintheFraserRiver.Int.Pac.SalmonFish.Comm.Prog.Rep.No.5.NewWestminister.BritishColumbia.Wangaard.D.B.andC.V.Burger.1983.EffectsofVariousWaterTemperatureRegimesontheEggandA1evinIncubationofSusitnaRiverChumandSockeyeSalmon.U.S.DepartmentofInterior.FishandWildlifeService.NationalFisheryResearchCenter.AlaskaFieldStation.Anchorage.AK.43pp.Ward.J.V.1976.Effectsofflowpatternsbelowlargedamsonstreambenthos:areview.pp.235-253.INJ.F.OrsbornandC.H.Allman(eds.).InstreamFlowNeeds.AmericanFisheriesSociety.Bethesda.MD.Ward.J.andJ.A.Stanford(eds.).1979.TheEcologyofRegulatedStreams.PlenumPress.NewYork.pp.398.Welch.S.1952.Limnology.2ndrd.McGrawHillBookCompany.Inc••NewYork.538pp.Wilson.W.J••E.W.Trihey.J.E.Baldridge.C.D.Evans.J.G.ThieleandD.E.Trudgen.1981.AnAssessmentofEnvironmentalEffectsofConstructionandOperationoftheProposedTerrorLakeHydroelectricFacility.Kodiak.Alaska.InstreamFlowStudies.Univ.ofAlaska.ArcticEnvironmentalInformationandDataCenter.Anchorage.AK.Witty.K.andK.Thompson.1974.Fishstrandingsurveys.pp.113-120.INK.BayhaandC.Koski(eds.).AnatomyofaRiver.PacificNorthwestRiverBasinsCommission.Vancouver.WA.Wojcik.F.1954.SpawninghabitsofgraylingininteriorAlaska.ReportNo.2bytheAlaskaGameCommission.Juneau.AK.fortheU.S.DepartmentoftheInterior,FishandWildlifeService,Washington,DC.Wojcik.F.1955.LifehistoryandmanagementofthegraylingininteriorAlaska.MSThesis.Univ.ofAlaska.Fairbanks.54pp.