Upper Missouri River Basin Water Year 2015 Summary of Actual Operations Water Year 2016 Annual Operating Plans U.S. Department of Interior Bureau of Reclamation Great Plains Region TABLE OF CONTENTS SUMMARIES OF OPERATION FOR WATER YEAR 2015 FOR RESERVOIRS IN MONTANA, WYOMING, AND THE DAKOTAS INTRODUCTION RESERVOIRS UNDER THE RESPONSIBILITY OF THE MONTANA AREA OFFICE SUMMARY OF HYDROLOGIC CONDITIONS AND FLOOD CONTROL OPERATIONS DURING WY 2015 ........................................................................................................................ 1 FLOOD BENEFITS ...................................................................................................................... 13 UNIT OPERATIONAL SUMMARIES FOR WY 2015 .............................................................. 15 Clark Canyon Reservoir ............................................................................................................ 15 Canyon Ferry Lake and Powerplant .......................................................................................... 21 Helena Valley Reservoir ........................................................................................................... 32 Sun River Project ...................................................................................................................... 34 Gibson Reservoir ................................................................................................................... 34 Pishkun Reservoir ................................................................................................................. 37 Willow Creek Reservoir ........................................................................................................ 38 Lake Elwell (Tiber Dam) .......................................................................................................... 46 Milk River Project ..................................................................................................................... 53 Lake Sherburne ..................................................................................................................... 53 Fresno Reservoir ................................................................................................................... 55 Nelson Reservoir ................................................................................................................... 57 Bighorn Lake and Yellowtail Powerplant ................................................................................. 66 RESERVOIRS UNDER THE RESPONSIBILITY OF THE WYOMING AREA OFFICE CLIMATE SUMMARY ............................................................................................................... 76 FLOOD BENEFITS ...................................................................................................................... 82 UNIT OPERATIONAL SUMMARIES FOR WY 2015 .............................................................. 83 Riverton Unit ............................................................................................................................. 83 Bull Lake Reservoir .............................................................................................................. 83 i Pilot Butte Reservoir ............................................................................................................. 85 Boysen Reservoir and Powerplant ............................................................................................ 91 Anchor Reservoir ...................................................................................................................... 97 Shoshone Project and Buffalo Bill Unit .................................................................................. 100 Heart Mountain Powerplant ................................................................................................ 100 Shoshone Powerplant .......................................................................................................... 100 Buffalo Bill Powerplant ...................................................................................................... 101 Spirit Mountain Powerplant ................................................................................................ 101 Buffalo Bill Dam and Reservoir .......................................................................................... 101 SUMMARY OF RESERVOIR OPERATIONS FOR BENEFIT OF FISH AND WILDLIFE, ENVIRONMENT, AND RECREATION Bull Lake Reservoir ................................................................................................................ 108 Boysen Reservoir .................................................................................................................... 108 Buffalo Bill Reservoir ............................................................................................................. 109 RESERVOIRS UNDER THE RESPONSIBILITY OF THE DAKOTAS AREA OFFICE WEATHER SUMMARY FOR NORTH AND SOUTH DAKOTA WY 2015 .......................... 110 FLOOD BENEFITS .................................................................................................................... 113 UNIT OPERATIONAL SUMMARIES FOR WY 2015 ............................................................ 115 Dickinson Reservoir ............................................................................................................... 115 Heart Butte Reservoir .............................................................................................................. 119 Jamestown Reservoir .............................................................................................................. 123 Deerfield Reservoir ................................................................................................................. 127 Pactola Reservoir .................................................................................................................... 131 Angostura Reservoir ................................................................................................................ 136 Keyhole Reservoir ................................................................................................................... 140 Shadehill Reservoir ................................................................................................................. 144 Belle Fourche Reservoir .......................................................................................................... 148 ii OUTLOOK AND OPERATING PLANS FOR WATER YEAR 2016 RESERVOIRS UNDER THE RESPONSIBILITY OF THE MOUNTANA AREA OFFICE Clark Canyon Reservoir ......................................................................................................... 153 Canyon Ferry Lake and Powerplant ....................................................................................... 158 Gibson Reservoir .................................................................................................................... 165 Lake Elwell (Tiber Dam) ........................................................................................................ 171 Milk River Project .................................................................................................................. 176 Lake Sherburne ................................................................................................................... 176 Fresno Reservoir ................................................................................................................. 177 Nelson Reservoir ................................................................................................................ 178 Bighorn Lake and Yellowtail Powerplant ............................................................................... 184 RESERVOIRS UNDER THE RESPONSIBILITY OF THE WYOMING AREA OFFICE Bull Lake ................................................................................................................................ 193 Boysen Reservoir and Powerplant .......................................................................................... 199 Buffalo Bill Reservoir and Powerplants ................................................................................. 203 RESERVOIRS UNDER THE RESPONSIBILITY OF THE DAKOTAS AREA OFFICE Dickinson Reservoir ............................................................................................................... 210 Heart Butte Reservoir ............................................................................................................. 210 Jamestown Reservoir .............................................................................................................. 210 Deerfield Reservoir ................................................................................................................. 211 Pactola Reservoir .................................................................................................................... 212 Angostura Reservoir ............................................................................................................... 213 Keyhole Reservoir .................................................................................................................. 213 Shadehill Reservoir ................................................................................................................. 213 Belle Fourche Reservoir 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