(Fremont County, WY) — Reclamation’s January forecast of the April through July runoff predicted for the Bighorn River Basin is as follows:
Bighorn Lake – Bighorn River April through July inflow to Bighorn Lake is forecast to be
approximately 1,277,000 acre-feet (af), which is 103% of the 30-year average of
1,235,000 af. As of January 1, Bighorn Lake is currently at 85% 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 January 1, Buffalo Bill is 71% full. *
Boysen Reservoir – Wind River April through July inflow to Boysen Reservoir is forecast at
700,000 af, which is 115% of the 30-year average of 611,000 af. As of January 1, Boysen
Reservoir is 83% full. *
Bull Lake Reservoir – April through July snowmelt runoff into Bull Lake Reservoir from Bull
Lake Creek is expected to be 150,000 af, which is 104% of the 30-year average of 144,200 af. As of January 1, Bull Lake Reservoir is 48% full. *
*Reservoir is considered “full” when the pool elevation is at top of active conservation or
joint-use pool. The percentage is based on total reservoir volume below that level.
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.