Bureau of Reclamation

03/14/2023 | Press release | Distributed by Public on 03/14/2023 14:36

Reclamation issues snowmelt forecast for Bighorn River Basin

BILLINGS, Mont. - Reclamation's March forecast of the April through July runoff predicted for the Bighorn River Basin is as follows:
  • Bighorn Lake - April through July inflow to Bighorn Lake is forecast to be approximately 1,283,000 acre-feet (af), which is 104% of the 30-year average of 1,235,000 af. As of March 1, Bighorn Lake is currently at 79% full. *
  • Buffalo Bill Reservoir - Shoshone River April through July inflow to Buffalo Bill Reservoir is forecast at 700,000 af, which is 94% of the 30-year average of 748,300 af. As of March 1, Buffalo Bill is 72% full. *
  • Boysen Reservoir - Wind River April through July inflow to Boysen Reservoir is forecast at 800,000 af, which is 131% of the 30-year average of 611,000 af. As of March 1, Boysen Reservoir is 79% full. *
  • Bull Lake Reservoir - April through July snowmelt runoff into Bull Lake Reservoir from Bull Lake Creek is expected to be 170,000 af, which is 118% of the 30-year average of 144,200 af. As of March 1, Bull Lake Reservoir is 49% full. *

*Reservoir is considered "full" when the pool elevation is at top of active conservation or joint-use pool.

The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles (160 km) wide, in north-central Wyoming. It is bounded by the Absaroka Range on the west, the Pryor Mountains on the north, the Bighorn Mountains on the east, and the Wind River and Granite Mountains on the south. It is drained to the north by tributaries of the Bighorn River, which enters the basin from the southwest, and passes through a gap between the Owl Creek and Bridger Mountains as the Wind River before changing its name to the Bighorn River at Wedding of the Waters, south of Thermopolis.

Reclamation's storage reservoirs in the basin have a combined storage capacity of 2.6 million acre-feet and most of that capacity is attributed to Bull Lake, Boysen and Buffalo Bill Reservoirs in Wyoming and Bighorn Lake in Montana. Hydropower is produced at Boysen Powerplant and four powerplants supplied by Buffalo Bill Reservoir in Wyoming and at Yellowtail Powerplant in Montana.

For additional information on Buffalo Bill, Boysen, and Bull Lake Reservoirs, contact Wyoming Area Manager Lyle Myler at 307-261-5671. For additional information on Bighorn Lake (Yellowtail), contact Montana Area Manager Ryan Newman at 406-247-7298.