Libby Dam spills extra water to promote sturgeon spawning
Federal agencies coordinate on spring spill at Libby Dam to promote spawning of Endangered White Sturgeon
by U.S. Army Corps of Engineers - Libby Dam media release
December 16, 2009
Boise, ID – Federal agencies are coordinating with the State of Montana and the Kootenai Tribe of Idaho to spill extra water at Libby Dam in the spring to promote spawning of the endangered Kootenai River white sturgeon. This spring spill operation is dependent upon the water supply in Lake Koocanusa, as well as other conditions.
The operation is part of an effort to encourage sturgeon migration in the Kootenai River upstream from Bonners Ferry, Idaho, into suitable spawning habitat in a cobble and gravel-bottomed stretch of the river.
The efforts follow a determination by the U.S. Fish and Wildlife Service (Service) that 2008 and 2009 operations did not help the protected sturgeon as much as a team of regional biologists had anticipated. The Service evaluated the effects of dam operations according to criteria set forth in a settlement agreement to the Service’s 2006 Biological Opinion, which outlines required protections for sturgeon affected by Libby Dam, and considers indicators of recovery such as sturgeon migration and spawning. A key requirement is for the Corps, which operates Libby Dam, and BPA, which markets its hydropower to provide river flows, depths, temperatures and gravels that encourage sturgeon to swim upriver for spawning.
The Service’s determination that dam operations did not meet the criteria for sturgeon two years in a row means that additional water will be released over the Libby Dam spillway for up to one week during late spring from 2010 through 2012. Biologists will evaluate the effects of the extra water on sturgeon migration and spawning.
The spills will occur sometime between late May and late June, depending on water supply forecast, runoff projections, water temperature and reservoir elevation. The U.S. Army Corps of Engineers (Corps) operates Libby Dam using variable flow flood control for multiple uses that are consistent with project authorizations and applicable laws and regulations, and will be responsible for providing the increased flows.
The Corps will coordinate the timing and other details with state officials, the Service, the Kootenai Tribe of Idaho, the Bonneville Power Administration (BPA), and other regional interests, assuring that conditions remain safe during the spill. The Corps will hold its annual public meeting in April or May to provide more detail on the 2010 operational plan, and federal, state and tribal representatives will also be present.
"The Corps' primary consideration is minimizing risk to human life, health and safety, while meeting Libby Dam's multiple purposes and responsibilities. The spill operation will be closely monitored to ensure that the spill test does not exceed flood stage below Libby Dam," said Mick Shea, Libby Dam operations manager.
Kootenai River white sturgeon were listed as an endangered species in 1994. They have not produced a significant number of offspring in the wild since 1974. Flood control and hydropower operations have altered the sturgeon’s habitat, affecting reproduction.
"Although hatchery reproduction has helped boost young sturgeon numbers in the river, the Service and our federal, state and tribal partners hope to improve habitat for this endangered fish. Increased flow during spring migration may encourage older sturgeon of spawning age to swim upriver into productive habitat for spawning, where their eggs would survive and thrive," said Jeff Foss, Idaho State Supervisor for the Service.
BPA funds habitat restoration and hatchery improvements through sales of hydropower generated at Libby Dam and 30 other federal dams in the Columbia Basin.
|
