Libby Dam discharge to decrease
Purpose is to benefit downstream fish habitat
July 20, 2005
According to a news release by the U.S. Army Corps of Engineers, Libby Dam will be decreasing discharge to approximately 19,200 cubic feet per second beginning Thursday, July 21st. Discharge will likely remain at this level for approximately 2 weeks, with additional incremental ramp downs through the summer targeting Koocanusa Reservoir elevation of 2,439’ (MSL) by the end of August.
The State of Montana has submitted a System Operation Request (SOR) for consideration of an operation that would entail a steady flow of approximately 11,000 cfs through the end of September, resulting in a draft of the reservoir to 2,439’ at that time rather than at the end of August. The flow request for Libby and Hungry Horse Dams is to provide water flows for bull trout and provide improved aquatic habitat conditions for other resident fish that inhabit waters above and below the reservoirs and in the downstream rivers. The objective is to stabilize summer flows in order to protect the downstream fish production below the dam by minimizing river flow fluctuations.
The change in flow request was a cooperative effort by the Montana Fish, Wildlife & Parks (MTFWP), the Kootenai Tribe of Idaho, and the Kootenei Salish Tribe. MTFWP will conduct a series of experiments to obtain information on fish survival and productivity of bull trout and resident fish populations below both dams.
Should this plan be approved by the regional forum, flows from Libby Dam would be reduced accordingly. Until the time that decision is made Libby Dam will follow the general incremental ramp down schedule as described, adjusting discharge as needed to target the end of August elevation in Koocanusa.
Montana’s SOR can be found on the web at:
http://www.nwd-wc.usace.army.mil/tmt/sor/2005/2005-MT-1_final_v2.pdf
Related Links:
Libby Dam
Lake Koocanusa
Kootenai River
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