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Libby Dam operations to benefit recreationists

by Canda HarbaughWestern News
| May 19, 2009 12:00 AM

Recreationists can expect a deep Lake Koocanusa for boating and a gentler Kootenai River for fishing this summer, Libby Dam officials said during Wednesday’s annual operations meeting.

“Fishermen should be dancing in the streets,” Brian Marotz of Montana Fish, Wildlife and Parks said.

Summer flow at Libby Dam will be altered this year as a result of a 2008 biological opinion that dictates operations of the Columbia River Power System to protect endangered salmon and steelhead trout.

The bi-op calls for less dam flow over a longer span.

“This keeps the reservoir fuller for longer periods of time, is fish friendly and is better for the nutrient system,” said Greg Hoffman, fishery biologist at Libby Dam.

The news may also please landowners along the river who tire of unnatural flow fluctuations that flood their property.

The Libby Dam water supply forecast for May is 18 percent below average, but a lower flow throughout the summer is expected to allow Lake Koocanusa to rise to within five feet of full pool.

The new plan calls for a steady flow of 9,000 cubic feet per second from July 1 through September, instead of pulling the plug on the reservoir in the peak of recreation season.

Last year, salmon flow volume began at 17,000 cfs on July 1 and was gradually reduced to about 8,000 cfs by the end of August. In past years, the summer flow volume was even higher. 

“You can’t fish in a river that has flows that high,” Hoffman said, “and it’s not good for fish either.”

The sturgeon and bull trout flows, which are based on a 2006 biological opinion, will run until the end of June. Though that flow schedule differs from year to year, Hoffman said that it would, in general, be similar to past years.

The sturgeon flow will peak at about 25,000 cfs the first week of June and descend down to 9,000 cfs by the end of June.

“By now most recreationists realize that a spike in flow in the spring is a natural river event, and that it’s good for the river,” Hoffman said. “Landowners may not like it, but most recognize it as necessary.”

Representatives from the Kootenai Tribe of Idaho also spoke at Wednesday’s meeting about the Kootenai River Habitat Restoration Project, which is working to address factors that limit the survival of endangered species.

Charlie Holderman, ecosystem project manager for the group, presented the initial findings of a nutrient experiment to stimulate ecological productivity in the Kootenai River.

Because much of the river’s nutrients are trapped at the dam, the Kootenai Tribe began in 2005 systematically adding a phosphorus solution at specific sites along the river. The result – an increase in algae, aquatic insects and some fish species. 

Though the findings are only preliminary, Holderman said they are promising. The group was hoping to restore the ecosystem as a whole and did not target a specific species.