Friday, December 08, 2023

Kootenai flows finally drop

| September 22, 2004 12:00 AM

Releases from Libby Dam dropped to 9,600 cubic-feet per second late Friday and are expected to be maintained through the end of September, according to U.S. Army Corps of Engineers.

The salmon mitigation flows, which result in the top 20 feet of Koocanusa Reservoir being drained, ended just over a week ago following discussion by the Libby subgroup of the Technical Management Team for the Columbia River System.

River managers are targeting a lake elevation at 2,439 feet above sea level by Sept. 30 and then gradual ramp-down to 4,000 cfs by Oct. 7.

Montana representatives argued for a steady flow for the remainder of the month with Brian Marotz, special fisheries project manager for Fish, Wildlife and Parks, lobbying for a flow of 9,000 cfs.

A Bonneville Power Administration representative said the power production agency is usually giving more ³flexibility² by the end of September to produce electricity. He said BPA would like more flexibility in flows for opportunities to make money for its ratepayers.

Last week, when the nearly two-and-half-month flow regimen of 12,500 cfs ended, flows were boosted to 14,000 cfs for power production, dropped to 12,000 cfs on Thursday and 10,000 cfs by Friday.

Marotz said dropping the flow to 9,600 does little or no damage to aquatic insects and fish, and is preferable to local fishermen and float boat guides. Also, it was easier on those aquatic ecosystems to drop to 4,000 cfs from 9,000, he said.

State officials had worked hard to build support for flows of 9,600 to 10,000 from mid summer through the end of September. Those representatives argued that Libby Dam¹s contribution to flows pushing salmon smolt out to sea couldn¹t be measured in the lower mainstem of the Columbia River and wouldn¹t be missed.

Downstream states argued that wasn¹t what is called for in the salmon recovery biological opinion.

Flows from Libby Dam have been steady at 12,500 cfs since mid July.

Some downstream interests are supporting the lower flows from Libby Dam now as a means of saving water in the reservoir for augmentation needs in November for endangered chum salmon in the Columbia.

BPA has already expressed concerns noting that the salmon biological opinion guiding water managers is not in effect at this time of year so that power production can occur at Northwest dams.

How much water will be kept at Koocanusa and how the ramp-down to 4,000 cfs will occur will be discussed at TMT meeting scheduled for Sept, 29.