Koocanusa Reservoir inflow forecast
May 10, 2005
According to the latest measurements by the U.S. Army Corps of Engineers, the April-August Lake Koocanusa Reservoir inflow forecast has changed little over the last month. The forecast dropped slightly between April and May from 86.4% to 81.6% of average. The lake water level is currently at 2424 feet, 35 feet below full pool level (full pool is 2459 feet).
At full pool, Lake Koocanusa is 370 feet deep, damming up the Kootenai River. The 90-mile long reservoir is divided roughly in half between the United States and Canada to the north. Normally the reservoir is lowered during the winter months for power production and to make room for the spring run-off. According to the terms of the Columbia River Treaty, the reservoir may be drawn down as much as 172 feet. As the spring run-off enters the reservoir, the lake fills. Fisheries biologists occasionally increase the outflow rate to benefit downstream fisheries values or for other reasons. Typically the lake is near full pool in time for the 4th of July holiday weekend and during the summer play months for boaters and campers along the lakeshore.
Dam managers are expected to start increasing the reservoir flow release rate into the Kootenai River sometime in late May to benefit white sturgeon, according to Libby Dam Fisheries Biologist Gregory Hoffman. The amount and duration of the augmentation is determined by the U.S. Fish and Wildlife Service’s sturgeon recovery team, composed of local and regional biologists and hydrologists.
Lake Koocanusa holds 13 percent of the total water stored in the Columbia River system, just slightly less than Grand Coulee Dam's storage. Beyond Libby Dam, the Kootenai River flows west past Libby and Troy, Montana, and into Idaho. At Bonners Ferry, it makes a turn to the north back into Canada where it merges with the Columbia River near Castle Gar, British Columbia. Most of the lakeshore on the U.S. side is part of the Kootenai National Forest and there is little commercial development along the lake, making this one of the most scenic lakeside camping and boating locations in northwest Montana.
Lake Koocanusa scenic photos