U.S. Army Corps of Engineers officials said 2025 is shaping up to be one of the driest years on record for Lake Koocanusa, with extremely low precipitation and a mostly depleted snowpack.

However, USACE officials said the Corps has, and will continue to meet all U.S. Fish and Wildlife Service and National Marine Fisheries Columbia River System biological assessment and biological opinion requirements, including those impacting the Kootenai River's white sturgeon.

Among those requirements are meeting the minimum sturgeon volume of 0.8 million acre feet for Tier 2 Water Year, bull trout minimum flow of 7,000 cubic feet per second through August and 6,000 cubic feet per second through September, and an end-of-September maximum target Lake Koocanusa elevation of 2,446.7 feet for juvenile salmon and steelhead flow augmentation in the Columbia River.

Although Libby Dam has released minimum discharge since January 2025, following USACE's flood risk management operations, water management officials with the Corps' Seattle District said what little remaining snowpack and forecasted inflows will likely result in a peak reservoir elevation this summer less than previously projected.

The current Northwest River Forecast Center runoff forecast for the Kootenai Basin above Libby Dam near Libby, Mont., from April through August is projected to be the third lowest in 74 years.

The Army Corps' official Water Supply Forecast at Libby Dam dropped from 4,944 kaf to 4,670 kaf between May 1 and June 1.

USACE officials indicate current modeling shows Lake Koocanusa will likely be drafted slightly below the 2,446.7-foot elevation target for end of September, and peak water elevation may be about 6 feet below the normal refill target of 2,454 feet, potentially impacting recreation at both Lake Koocanusa's beaches and boat docks.

USACE officials said the final Army Corps' May WSF determines the volume of water released for Kootenai River white sturgeon, the minimum discharge for bull trout downstream of Libby Dam during the summer months, and the target Lake Koocanusa elevation at the end of September.

As the Water Year progresses, USACE officials said they will continue to coordinate, as needed, with agencies and regional managers, including the Columbia River Basin technical management team.

Located between Canada and Montana, the reservoir was formed by the damming of the Kootenai River by the Libby Dam in 1972.