BOISE, Idaho -- The U.S. Army Corps of Engineers, Walla Walla District, in coordination with the Bureau of Reclamation, will begin the seasonal drawdown of Lucky Peak Reservoir on Monday, Aug. 10, in preparation for fall and winter operations.
The Boise River reservoir system is currently 66% full and continues to supply summer water needs. With Arrowrock Reservoir currently at 25% capacity and expected to reach its seasonal minimum pool early next week, Arrowrock Dam will reduce releases into Lucky Peak on Aug. 10. This reduction initiates Lucky Peak’s seasonal drawdown, which will draft the reservoir from its current elevation of 3,055 feet down to a winter pool of approximately 2,945 feet by the end of the fall irrigation season.
Lucky Peak's initial drawdown rate is expected to be approximately 1.5 feet per day, a slight change from the 2 feet per day estimate provided in July.
Currently, Lucky Peak Dam is releasing 3,380 cubic feet per second, and the Boise River is measuring 639 cfs at the Glenwood Bridge. Lucky Peak Dam releases will continue to be based on downstream water supply needs and will not increase to facilitate this drawdown operation. Boise River flows are expected to remain fairly consistent over the next few weeks.
As reservoir elevations decrease, visitors are encouraged to plan accordingly. Lower water levels will affect boat ramp accessibility and other recreational opportunities around the reservoir throughout the drawdown period.
Lucky Peak Reservoir is one of three reservoirs in the Boise River system that work together to provide flood risk management, irrigation storage, hydropower generation, recreation and environmental benefits throughout southwest Idaho.
The timing and rate of the drawdown may be adjusted based on real-time weather conditions and irrigation demand. For real-time water management information and operational updates, the public is encouraged to visit: https://www.nww.usace.army.mil/Missions/Water-Management/.
Release no. 26-029