Yellowtail Dam

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RECLAMATION
Managing Water in the West
Yellowtail Dam Bighorn Lake Billings,
Montana January 2011
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Operating Requirements Objectives

• Mandatory /Legal
• Recognize all senior downstream water rights
• Fulfill compact obligation with Native American
  Tribes
• Meet contract commitments for stored water
• Dam safety
• Operating Objectives
• Maximize power generation benefit
• Maintain storage space for flood control
• Maintain desired lake levels for recreation,
  reservoir fishery and waterfowl
• Maintain desired river flows for the river
  fishery and water quality

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Multipurpose Benefits

• Water Rights
• Regulate stream flow and release water for
  irrigation
• Compact Commitments with N. Cheyenne and Crow
  tribes
• Industrial water supply
• 6,000 AF contract with PPL- MT
• Flood control
• Flood protection Benefits 113 million since
  construction (2007)
• Hydropower
• 260 MW powerplant (8,000 cfs)
• Peaking power supplied to two grid systems
• Average Annual generation 866.0 million kwhrs
  (1967-2007)
• Average Annual power sales _at_ .023/kwhr 20
  million per year
• Montana and Wyoming both benefit from power
  generated
• Fish Wildlife
• Lake fishery, river fishery, and waterfowl
• Recreation
• Bighorn Canyon Recreation Area and Bighorn River
• Water Quality
• Reduce high levels of nitrogen supersaturation

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Operational GoalsPrior to Review

• Desired lake elevations requested by lake
  interests
• Minimum desired lake elevation recommended by the
  NPS for the summer recreation season - 3617.
• Minimum late fall lake elevation recommended by
  the Wyoming Game and Fish to provide suitable
  waterfowl habitat - 3635.
• Draft reservoir to 3630 to prevent ice-jams from
  forming in low end of Shoshone River
• Maximum lake elevation recommended by the NPS for
  the summer recreation season to protect
  facilities - 3642.
• A rising reservoir level through the spring for
  walleye spawning.

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Operational Goals (continued)

• Desired river flows requested by Montana FWP by
  letter dated November 19, 1986
• 2,500 cfs to provide good spawning, rearing and
  cover conditions in all major side channels.
• 2,000 cfs - to provide adequate spawning and
  rearing conditions in most side channels but
  cover for adult fish is limited.
• 1,500 cfs to provide only main channel habitat
  and no side channel habitat
• Minimum release included in the 1962 Definite
  Planning Report for the Yellowtail Unit 1,000
  cfs

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Operational Goals (continued)

• Power generation
• Utilize available water supply to maximize
  generation at time of greatest demand
• Maximize reservoir head to provide the greatest
  generation per unit of water
• Flood control
• Coordinate operations with the Corps of Engineers
  to provide system benefits
• Draft water from the Joint-Use pool based on
  mountain snowpack forecast to provide space for
  expected runoff while allowing the reservoir to
  fill to the top of the joint-use pool by end of
  July.
• Operate the Exclusive flood pool as directed by
  the Corps of Engineers to control rain flood
  events and high snowmelt runoff.

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QUESTIONS COMMENTS