Seventeen miles north of Libby, MT on Highway 37, the 422 foot high, 3055 foot long concrete gravity dam was built and is operated by the United States Army Corps of Engineers. The five generators in the powerhouse are capable of generating 600 Megawatts of electricity.
While it seemed like a good idea at the time to mitigate downstream flooding and produce electricity, more or less as a byproduct, it seems the dam is creating as many problems as it is solving. In human terms, while there's no debating the value of reducing or eliminating flooding in the Kootenai River Basin, there is a great amount of debate over the dam's negative influence on fish populations in the river. One species in particular, the Kootenai River white sturgeon, has inhabited the river since the last ice age but is now considered very much an endangered species, primarily as a result of the change in the sturgeon's spawning grounds caused by the presence of the dam.
A news story printed in the Los Angeles Times, reprinted in part below, explains.
Alteration of water spill over Montana's
Libby Dam may help endangered
Kootenai River white sturgeon
JUNE 10, 2010
SPOKANE, Wash. — The latest effort to save North America's largest freshwater fish from extinction begins this week when water is spilled over Montana's Libby Dam to encourage the ancient fish to spawn for the first time in more than three decades.
The wild Kootenai River white sturgeon, a toothless beast from the days of dinosaurs, has a large head, armor-like scales, can reach 19 feet long and top 1,000 pounds. It takes 20 or 30 years for white sturgeon to mature and reproduce.
An isolated population of the bottom-feeding behemoths lives along a stretch of the Kootenai that passes through Montana, Idaho and British Columbia, Canada. The construction of Libby Dam in 1974 stopped the river from flooding Bonners Ferry, Idaho, but also prevented the high-water flows that triggered the sturgeon to move upriver and spawn.
Before the dam, there were an estimated 10,000 Kootenai sturgeon. Fewer than 500 mature adults of spawning age remain.
The effort this week will spill up to 10,000 cubic feet of water per second over the dam in a huge waterfall for up to seven days, in what scientists hope will push the sturgeon to more productive spawning grounds in Idaho. The water will spill from Koocanusa Reservoir into the Kootenai River, where scientists hope the sturgeon will swim to the Bonners Ferry area.
The U.S. Army Corps of Engineers on Tuesday began sending more water through the dam's turbines, in preparation for opening spill gates Thursday.
"The idea is to re-create more of the natural spring conditions," said Michael Milstein of the U.S. Bonneville Power Administration, which markets the power from the dam. "That is believed to be a factor that led sturgeon upriver to spawn."
It's not known if the ploy will work. Scientists will track the sturgeon to see whether they are moving and spawning, said Nola Leyde of the Army Corps.
Biologists say the wild fish could become extinct within the next decade unless a fix is found. But sturgeon will not disappear from the river.
Idaho's Kootenai Tribe of Indians has stocked the river since the 1990s with thousands of hatchery-raised sturgeon. But the Endangered Species Act requires a species to reproduce naturally to be considered recovered.
Read on at the Los Angeles Times