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VES~9h/000l Operation of Dam Glen Canyon Draft Environmental Impact Sta U. S. Department of the Interior Bureau of Reclamation Acronyms and Abbreviations AGC Automated generation control kW Kilowatt AGFD ArizonaGame and Fish kWh Kilowatthour Department LCR Little Colorado River AMWG Adaptive ManagementWork Group maf Million acre-feet AOP Annual operating plan mg/L Milligrams per liter BIA Bureau of Indian Affairs MW Megawatt CFR Code of Federal Regulations MWh Megawatthour cfs Cubicfeet persecond NEPA National Environmental PolicyAct Corps U.S. ArmyCorps of Engineers NERC North American Electrical CROD Contract Rate of Delivery ReliabilityCouncil CRSM Colorado RiverSimulation Model NHWZ Newhigh waterzone CRSP Colorado RiverStorage Project NOx Nitrogen oxide CRSS Colorado RiverSimulation System NPS National Park Service DO Dissolved oxygen OHWZ Old high waterzone DOE Departmentof Energy P.L. Public Law EIS Environmental impact statement Reclamation Bureau of Reclamation °F Degree Fahrenheit RM Rivermile FERC Federal Energy Regulatory ROD Record of decision Commission SLCA Salt Lake City Area FONSI Finding of no significant impact SLCA/1P Salt LakeCity Area Integrated FWCA Fish andWildlife Coordination Act Projects FWS U.S. Fish and Wildlife Service S02 Sulfurdioxide GCES Glen Canyon Environmental SRP Salt River Project Studies use United States Code GLCA Glen Canyon National Recreation Area USGS U.S. Geological Survey GRCA Grand Canyon National Park WAUC Western Area UpperColorado GWh Gigawatthour Western Western Area PowerAdministration IMPLAN U.S. Forest Service input-output WSCC Western Systems Coordinating economic model Council hr Hour > Greaterthan IPP Inland Power Pool < Less than kV Kilovolt Draft Environmental Impact Statement OperationofGlen Canyon Dam Colorado RiverStorage Project Coconino County, Arizona CooperatingAgencies: U.S. Departmentofthe Interior Bureau ofReclamation (lead agency) Bureau ofIndian Affairs Fish and Wildlife Service NationalParkService U.S. DepartmentofEnergy WesternArea PowerAdministration Arizona Gameand Fish Department HopiTribe Hualapai Tribe Navajo Nation Pueblo ofZuni SanJuanSouthern PaiuteTribe Southern Utah PaiuteConsortium ForFurtherInformation Contact: Mr. Lee McQuivey J. ColoradoRiverStudiesOffice BureauofReclamation PO Box 11568 SaltLakeCity UT 84147 (801) 524-5479 This draftenvironmental impactstatement (EIS) analyzes the impacts ofoperations from 1963 to 1990 (baselineconditions) and alternative operations ofGlenCanyon Dam on downstream environmentaland cultural resources ofGlen and Grand Canyons. Alternative operations evaluated include three thatwouldprovide steady flows; three thatwould provide various levels offluctuating flows; and two, including no action, that would provideunrestricted fluctuating flows. Additionalmeasureshavebeencombined with the alternative operations, where appropriate, toprovide additional resource protection orenhancement. The preferred alternative is theModified Low FluctuatingFlow Alternative. This draftEISwasprepared in compliance with theNational Environmental Policy Actand Bureau ofReclamation procedures and is intended to serveenvironmental review and consultation requirements pursuant to ExecutiveOrder 11988 (Floodplain Management), Executive Order 11990 (Wetlands Protection), National Historical Preservation Act (Section 106), Fish and WildlifeCoordinationAct, and Endangered SpeciesAct (Section 7c). Itisessential that those interested in this proposed action participate during the90-day comment period. Tobe mosthelpful, comments on thedraft shouldbe as specific aspossible and address the adequacy of the statement or the merits ofthe alternatives. Further, the Department ofthe Interior is not required to seekcomments on the final EIS. Itis, however, providing twice the amountof time for commenton the draft EIS than is requiredby the regulations. Therefore, you areencouraged to raise allcomments, recommendations, orobjections on the draft EISso thatsubstantivecomments are made available to the lead agency in time forit tomeaningfully considerand respond to them in thefinalEIS. Comments mustbereceivedby April 11, 1994. Digitized by the Internet Archive in 2012 with funding from LYRASIS Members and Sloan Foundation http://archive.org/details/operationofglenc001993 \ UTAH r1 ARIZONA SI UNITED STATES DEPARTMENTOF THEINTERIOR BUREAUOFRECLAMATION GLEN CANYON DAM ENVIRONMENTAL IMPACT STATEMENT MAP GENERAL DENVER COLORADO MAY 1993 GOVERNMENT 5 Contents Page General location map Frontispiece ChapterI Purpose ofand need foraction 1 Background 2 Cooperatingagencies 3 Managementresponsibilities 4 Documentorganization 5 Location and setting 5 Grand Canyon National Park 5 Historicalperspective 6 Predam flows 6 Postdam flows (historic operations) 6 GlenCanyon Damoperations 6 Authorities and institutionalconstraints 7 Grand Canyon ProtectionActof1992 (PublicLaw 102-575) 8 Law oftheRiver 8 Nationalparks 8 Environmental 9 Culturalpreservation 9 NativeAmerican 9 Glen Canyon EnvironmentalStudies 9 Phase I (1982-88) 10 Phase II (1988-present) 10 RelationshipbetweenGlenCanyon Dam EIS and Electric PowerMarketing EIS 11 Scopingsummary 11 Public issues and concerns 11 Significantissues identified fordetailed analysis 12 Chapter II Description ofalternatives 15 Process used to formulatealternatives 15 Alternativesconsidered in detail 16 Unrestricted fluctuating flows 16 NoAction Alternative 16 Maximum PowerplantCapacityAlternative 24 Restricted fluctuating flows 24 HighFluctuatingFlow Alternative 26 Moderate FluctuatingFlow Alternative 27 Modified Low Fluctuating Flow Alternative (Preferred Alternative) 27 Interim Low Fluctuating Flow Alternative 30 Steadyflows 30 ExistingMonthly Volume Steady Flow Alternative 32 SeasonallyAdjusted Steady Flow Alternative 33 Year-RoundSteady Flow Alternative 33 Common elements 34 Adaptivemanagement 34 Monitoringand protecting cultural resources 35 Flood frequency reduction measures 36 Beach/habitat-building flows 36 iii Contents Page New population ofhumpbackchub 38 Furtherstudy ofselectivewithdrawal 38 Emergencyexception criteria 39 Mitigation 39 Power adjustments 39 Permits and regulatory approvals 40 Alternativesconsidered and eliminated from detailed study 40 Run-of-the-RiverAlternative 40 Evaluationofalternative 41 Conclusions 42 Historic PatternAlternative 43 Evaluationofalternative 44 Conclusions 44 Reregulated Flow Alternative 44 Evaluation ofalternative 45 Conclusions 47 Eliminated concepts 48 Sand pumping 48 Beach protection 48 RemoveGlenCanyon Dam - 49 Movehydropowerpeaking fromGlenCanyon Dam to HooverDam 49 Summarycomparison ofalternatives 50 ResourceManagementObjectives 50 ChapterIII Affected environment 63 Setting 63 Immediate area 63 Colorado Riverregion 64 Geology 64 •. Climate 65 Colorado Riversystem resource linkages 65 Watervolume and pattern ofrelease 66 Sedimenttransportand its effecton otherresources 68 Flows, sediment, and downstream resources 68 Aquatic resources 68 Terrestrial resources 70 Summary 71 Water 71 Streamflows 72 Predam streamflows 72 Postdam streamflows 73 Downstream transformation offluctuating releases 75 Travel time ofwater 77 Tributary flows 77 Floodflows and otherspills 77 Reservoirstorage 78 Waterallocation deliveries 79 Upper Basin yield determination 79 IV Contents Page Waterquality 80 LakePowell 80 Colorado Riverbelow Glen Canyon Dam 82 Sediment 83 Background 83 Riverbed sand 84 Deliveryto theColorado River 86 Main channel transportand storage 88 Sandbars (beachesandbackwaters) 91 Recirculation zones (eddies) 92 Sandbardeposition and erosion 94 High terraces 97 Debris fans and rapids 97 Lake deltas 99 Lake Powell deltas 99 Lake Mead delta 101 Fish 103 Aquatic foodbase 103 Cladophora and associated diatoms 104 Otheraquatic food sources 105 Native fish 106 Reproduction 107 Recruitmentand growth 108 Non-nativewarmwaterandcoolwaterfish 109 Trout Ill Vegetation 114 Riparian vegetation 114 Woody plants 115 Emergentmarshplants 118 Wildlife and habitat 119 Riparianhabitat (woody and emergentmarsh plants) 120 Mammals 120 Birds 121 Amphibians and reptiles 122 Terrestrial invertebrates 123 Wintering waterfowl (aquatic foodbase) 124 Endangered and otherspecial status species 124 Endangered species 125 Humpbackchub 125 Razorbacksucker 127 Bald eagle 128 Peregrine falcon 128 Kanab ambersnail 129 Otherspecial status species 129 Flannelmouth sucker 129 Southwestern willow flycatcher 129 Arizona species ofconcern 130 Culturalresources 130 Archeological sites 130 Contents Page Native American traditionalcultural properties 131 HavasupaiTribe 131 HopiTribe 132 HualapaiTribe 133 Navajo Nation 134 Southern PaiuteTribe 135 ZuniTribe 135 Airquality 136 Grand Canyon airquality 136 Sulfates 137 Regionalairquality 138 Recreation 138 Fishing 139 Fishing in GlenCanyon 139 Fishing in GrandCanyon 141 Day rafting 141 Trip attributes 142 Navigability, access, andboating safety 142 White-waterboating 142 River trip attributes 143 Wilderness values 144 Safety 144 Handicapped accessibility 145 Campingbeaches 145 Lake activitiesand facilities 149 Recreationat LakePowell 149 Navigability ofupperLake Mead 149 Economics ofrecreational use 150 Recreationusein thestudy area 150 Net economic value ofrecreation 150 Regional economic activity 152 Recreation, economics, and Indian Tribes 153 Hydropower 155 Poweroperations 156 Operationalflexibility 157 Powermarketing 160 Long-term firmpower 160 Short-term firm power 161 Nonfirmenergy 161 SLCA/IP post-1989powermarketingcriteria 161 Marketable resources 161 Wholesaleand retail powerrates 162 Non-usevalue 163 Marketvalue, non-market value, andnon-use value 163 Conceptualbasis fornon-use value 163 Evidence ofthe relative magnitude ofuseandnon-use value 164 Potential non-use value forhydroelectric power 165 Implications ofnon-use values 165 Estimatingnon-usevalue forthis EIS 165 VI