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Salmon/Hydro Managers Consider Operation Changes For Libby Dam/Kootenai River Flows During Low Water
Posted on Friday, May 08, 2015 (PST)

Two requests to change management of the Kootenai River, the third largest tributary of the Columbia River, received a cool reception from fisheries managers at this week’s Technical Management Team meeting, and one of those, a request to deviate from VARQ on the river was denied.

 

The Kootenai Tribe of Idaho and the U.S. Fish and Wildlife Service asked permission from TMT to maintain low flows in the river at 6,000 cubic feet per second or less in September and October to accommodate habitat improvement construction in the river.

 

Even in a low water supply year, TMT fisheries managers worried the operation would reduce flows needed for fish migrations in the lower Columbia River and will likely suggest revisiting the operation closer to September after it knows more about water supply in Lake Koocanusa, which backs up behind Libby Dam in Montana, and available flows.

 

A second request from the Service is to provide additional water releases from Libby Dam to augment flows for sturgeon and bull trout spawning. It received a warmer reception as the operation would increase flows in the lower rivers.

 

Decisions for both of these Special Operations Requests (SOR) were put off to next week’s TMT meeting, May 13.

 

A third operation request from the Service was to deviate from VARQ, the flood control rule in the Kootenai River, by dropping stream flows immediately from the required VARQ flow of 18 cfs to 13 cfs.

 

“This year is unique,” said the Service’s Jason Flory. “There is a lot going on and not a lot of water.”

 

He said VARQ at 18 cfs is high considering this year’s hydrologic conditions in which there is almost no risk of flooding on the river. It would help fill Lake Koocanusa higher by an additional three feet and push more available water from this month to June through August.

 

As it stands in this low water year, the reservoir could be drafted to an elevation of 2,439 feet by the end of September, rather than the 2,449 that has occurred in recent years. Full pool is 2,459 feet elevation.

 

For more information, see CBB, May 1, 2015, “Low Water Forecasts At Dalles Dam Will Impact How Much Montana Reservoirs Will Be Drawn Down,” http://www.cbbulletin.com/433882.aspx.

 

TMT denied the Service’s request, saying it needed the output at Libby Dam now to provide more river flow further downstream in the Columbia River to help pass migrating juvenile salmon at the dams.

 

“The consensus (among TMT fisheries managers), this year particularly with low flows and McNary at 170 kcfs, which is not desired, is to continue to move water downstream from Libby during the spring migration,” said Paul Wagner of NOAA Fisheries. “We’re struggling to keep the flows up at McNary and also to refill Coulee in June.”

 

Variable flow, or VARQ (Q refers to flow), flood control has been in effect at Libby Dam since 2003. In 2009, the U.S. Army Corps of Engineers signed a Record of Decision for the flood control plan.

 

Prior to the ROD, the dam would generally release high flows from January through April in order to make space to capture the spring runoff in May, June, and July. Because of the large amount of water drafted, historically little water was released from May through July period to allow refill of the reservoir.

 

During the draft season in a majority of years VARQ provides less flood storage space than standard flood control in Libby's reservoir, Lake Koocanusa. During the spring-early summer refill, water releases from the dam will vary based on the year's April-August water supply forecast for the basin. The water release adjustments compensate for the reduced winter reservoir draft under VARQ.

 

VARQ also helps by stabilizing flows downriver in all but the highest water years by sending more water downstream in spring and early summer.

 

The first SOR of the year for TMT came from USFWS and Idaho Fish and Game requesting flows for sturgeon and bull trout.

 

Based on the 2006 Biological Opinion for Libby Dam operations, the April to August runoff forecast of 5.4 million acre feet make operations for Kootenai River white sturgeon a Tier 2 year, which  allows for .8 million acre-feet of water to be released, but all in one  peak (in past years with better water supplies, it has been a two-peak operation).

 

The operation is to provide sturgeon in the river with cues to begin their upstream migration to staging areas, and when river temperatures warm to move into spawning areas. “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. The timing is May into July.

 

The SOR is at http://www.nwd-wc.usace.army.mil/tmt/agendas/2015/0506_2015_USFWS_Libby_sturgeon_SOR.pdf.

 

The second SOR from the Kootenai  Tribe of Idaho and USFWS is to provide low flows of no more than 6 cfs in September and October to accommodate instream construction of a habitat project near Bonners Ferry Island.

 

The project is the latest in a series of habitat projects aimed at restoring nearly 50 miles of habitat downstream of Libby Dam at a total cost of $30 million over the past six years.

 

The project, which will be done over two construction seasons, includes construction of two islands on mid-channel gravel bars of about 18 total acres, excavation of three 20 foot to 30 foot pools, construction of two large and two smaller pool-forming structures, and bank grading and revegetation, according to the SOR.

 

The SOR is at http://www.nwd-wc.usace.army.mil/tmt/agendas/2015/0506_2015_KRHRP_SOR_FINAL_April_27_2015_db.pdf.

 

TMT will act on SOR 2015-1 and 2015-2 at its next regularly-scheduled meeting Wednesday, May 13.

 

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