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River Managers To Boost Flows From Libby Dam To Aid Kootenai River White Sturgeon Spawning
Posted on Friday, May 12, 2017 (PST)

Flows from Libby Dam will spike next week to benefit wild Kootenai River white sturgeon, but this year river operators will increase flows twice – once to encourage the sturgeon to move upriver into spawning grounds and a second time to trigger further movement upstream and spawning.


The double spike this year comes courtesy of a much higher than normal snowpack and winter precipitation and an April to August water supply forecast of 8.19 million acre feet, which is 139 percent of normal, according to Jason Flory of the U.S. Fish and Wildlife Service.


That’s a Tier 5 year for sturgeon operations, he said, which means that at least 1.2 MAF can be discharged from Libby Dam, which is near the towns of Libby, Montana and Bonners Ferry, Idaho. The operation is defined in the Service’s 2006 biological opinion for Libby operations, covering both sturgeon and bull trout.


Flory introduced the sturgeon operation in a System Operations Request FWS #1 to the interagency Technical Management Team for their approval at TMT’s meeting this week Wednesday, May 10 (


“Overall, the goal is to provide conditions that will enable sturgeon to migrate to, and spawn over, rocky substrates that exist upstream of Bonners Ferry,” the SOR says. “This two-peak approach was successfully implemented in 2013 and 2014. Telemetry data for spawning Kootenai sturgeon females from those years indicate that a higher proportion migrated just upstream of Bonners Ferry than in recent years.”


Libby Dam’s sturgeon operations are the first releases of the year for fisheries benefits at federal hydro projects. Elevated releases are carried out the remainder of the summer and early fall to benefit salmon and steelhead runs.


The first peak, which begins Monday, May 15, will coincide with low elevation snow melt, Flory said, and the second peak will be triggered when the higher elevation snow begins to melt.


The first five to seven day pulse of water will be at full powerhouse capacity, or about 25,000 cubic feet per second. During this peak, the dam’s selective water withdrawal gates will remain uninstalled, according to the SOR. That will allow river operators to conserve warmer surface water that will be used “during the second descending limb of the second peak.”


Flows will then briefly drop to a level that would result in flows at Bonners Ferry of about 18 kcfs until the second peak begins.


High elevation snowmelt in the Kootenai River basin will trigger the second pulse, bringing discharge at the dam up to full powerhouse capacity (depending on local conditions in the river at Bonners Ferry).


Towards the end of this second peak, warmer water will be released to raise the river to sturgeon spawning temperature of 8 to 10 degrees Celsius (about 46 to 50 degrees Fahrenheit). The second peak will last 7 to 14 days, or until the sturgeon volume is exhausted, according to the SOR.


At that time, discharge from the dam will be set at bull trout minimum flows of no less than 9 kcfs.


Once the sturgeon and bull trout operations are complete, discharge at the dam will drop to 6,000 cubic feet per second in September and into the first week of November to accommodate a long-term Kootenai River restoration project.


Sue Ireland, fish and wildlife director for the Kootenai Tribe of Idaho, and Joel Fenolio, Upper Columbia River senior water manager with the U.S. Army Corps of Engineers, proposed lower flows to accommodate Kootenai River habitat restoration work near Bonners Ferry that is dubbed Lower Meander Project. While this particular work will go on for two years, the entire habitat project had actually begun in 2011, Ireland told TMT.


See SOR 2017-1:


The Lower Meander Project will “improve habitat conditions in the Kootenai River to help adult sturgeon migrate upstream, improve spawning habitat, increase juvenile rearing habitat, and improve overall ecosystem function,” the SOR says.


The work includes bank structures for bank stability, but it will also help maintain deep pools, Ireland said.


Workers will establish a sequence of high-quality and deeper pools in the river to support sturgeon migration to upstream habitats in the Braided and Canyon reaches, the SOR continues. Fill and plantings will be added to existing islands to promote riparian development and provide food web support. Workers will also add woody debris in side channels and along bank margins to improve habitat complexity.


Also see:


--CBB, May 20, 2016, “Elevated Flows At Libby Dam Aimed At Benefitting Kootenai River Sturgeon,”


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