Reclamation issues snowmelt forecast for Bighorn River Basin

Reclamation’s April Forecast of the May through July water runoff predicted for the Bighorn River Basin is as follows:

•Boysen Reservoir - Wind River May through July inflow to Boysen Reservoir is forecast at 580,000 af, which is 101% of the 30-year average of 573,000 af. As of May 1, Boysen Reservoir is 76% full. *

•Bighorn Lake -Bighorn River May through July inflow to Bighorn Lake is forecast to be approximately 704,000 acre-feet (af), which is 65% of the 30-year average of 1,080,000 af.  As of May 1, Bighorn Lake is 79% full.*

•Buffalo Bill Reservoir - Shoshone River May through July inflow to Buffalo Bill Reservoir is forecast at 520,000 af, which is 73% of the 30-year average of 707,500 af. As of May 1, Buffalo Bill is 72% full. *

•Bull Lake Reservoir - May through July snowmelt runoff into Bull Lake Reservoir from Bull Lake Creek is expected to be 140,000 af, which is 99% of the 30-year average of 142,000 af. As of May 1, Bull Lake Reservoir is 51% 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.