Wednesday, June 07, 2023

River flows start slow ramp-down

| July 25, 2005 12:00 AM

By ROGER MORRIS Western News Publisher

While a system request from the State of Montana to reduce flows from Libby Dam is being mulled over by federal water managers for the Columbia River system, a slower ramp-down proposal from the U.S. Army Corps of Engineers was okayed and the river should begin dropping bnesday, releases from Libby Dam were at powerhouse capacity, 25,000 cubic-feet per second. At 10 p.m. on Thursday, the Corps will begin reducing those flows by dropping down to 19,000 cfs with the river eventually coming down to 14,000 to 15,000 by early August, said Greg Hoffman, fisheries biologist at Libby Dam.

"Montana's System Operating Request, which would flat flow the river from now through the end of September at about 11,000 to 12,000 cfs is still up in the air but it doesn't look good," Hoffman said. "So in lieu of that, I put together a staged ramp-down scenario, which has been reviewed and approved by the Corps' Reservoir Control Center and the Technical Management Team."

Because of better than expected runoff from Canada, the Corps has been releasing high amounts of water from the dam to match the reservoir inflow since late spring. As a result the Kootenai River below the dam has been high, making it difficult for recreationists to approach the river for fishing.

Under the biological opinion to recover endangered salmon in the Columbia River, the Corps is required to begin draining the top 20 feet from Lake Koocanusa behind Libby Dam by Aug. 31. The river system plan then calls for flows to drop to 9,000 cfs and perhaps as low as 6,000 or 7,000 cfs in September.

Hoffman noted that such a large drop in flows would dry up the riverbanks killing off valuable insects that make the Kootenai River a valued fishery. That would immediately impact the fishing in September and the long-term health of the fishery.

State officials would like to see a steady flow of 11,000 to 12,000 cfs through the end of September. That proposal was discussed in a TMT meeting early Wednesday with no decision being reached. The proposal is now being kicked up to the next level — to the managers of the various agencies that control the Columbia River system. Those agencies include the Bonneville Power Administration, the National Marine Fishery Service, the U.S. Fish & Wildlife Service, the Corps, the U.S. Bureau of Reclamation, state fish and game officials, power companies and tribal representatives.

Under Hoffman's plan, the releases will drop to 19,000 cfs for this weekend and next week and then drop again to 14,000 to 15,000 in early August before settling "for a couple of weeks" at 12,000 cfs. His proposal calls for continued reductions to 9,000 cfs and then down to 6,000 or 7,000 cfs in September.

The slow ramp-down to 6,000 cfs protects the fishery by slowly drying the insect habitat on the riverbanks.

"For multiple reasons, ramping down is the lesser of the two evils," Hoffman said.

Montana proposed a similar strategy last year and was turned down by the National Marine Fisheries, the federal agency responsible for salmon recovery. NMFS officials expressed concerns with not having the scientific evidence that the lower flows were not adversely impacting Columbia River salmon.

The Montana SOR this year calls for ongoing studies to show both the benefit to the Kootenai River fishery and no harm to downstream salmon. It is a plan endorsed by the Northwest Power Planning Council, which includes two representatives from the governors of the four Northwest states, in its Mainstem Amendments for managing the Columbia River system.

Hoffman said the TMT discussion Wednesday on Montana's request centered on the technical merits of the SOR. There is a basic philosophical disagreement between downstream interests and Montana, he said.

"Montana is using baseline biology and trying to sell that," Hoffman said. "Montana's proposal protects river habitat while the bulk of salmon managers look at the number of fish downstream."

And there is a reluctance to vary too far from the salmon bi-op, which has been challenged successfully in federal courts.