BOISE - State water managers have voted to spend $2 million to study building a big new dam on western Idaho's Weiser River.

The Weiser-Galloway dam has long been a dream of Gov. Butch Otter, power companies and others with their eye on this site not far from Midvale as a means of boosting water storage, fulfilling obligations to help endangered salmon and steelhead and boosting electricity production downstream on the Snake and Columbia rivers.

The Idaho Water Resources Board voted unanimously Friday to further assess whether the site would safely accommodate a dam and reservoir, including by taking core samples to make sure the river banks will support such a structure.

That's critical, given Idaho's history of catastrophic dam failures, with the Teton Dam's collapse in 1976 killing 11 people and 13,000 cattle.

Jack Peterson, the Idaho agency's liaison with the federal government, called the board's vote Friday "courageous" because "it's been a long time - 40 or 50 years - since a major storage site has been examined in the American West."

An irrigation diversion dam already has been built near the proposed dam site.

The massive structure foreseen to replace it, according to its promoters, would be strategically located, providing a water source to help reduce temperatures on the degraded Snake River where the Idaho Power Co. has slackwater reservoirs behind the three dams that form its Hells Canyon hydroelectric complex.

In addition to providing water to improve fish habitat downstream, a new dam could also provide irrigation and flood control along the Weiser River's course that extends to its headwaters 50 miles upstream in the Nez Perce National Forest near the Seven Devils Mountains.

Just last March, the Idaho Water Resources Board and the U.S. Army Corps of Engineers completed a new analysis of the Weiser-Galloway project, concluding there were two major gaps in information that needed to be remedied before dedicating even more money toward a comprehensive feasibility study.

The $2 million approved - which is being taken from the state water agency's revolving development account that finances project to boost Idaho's water supply - will pay for taking and analyzing core samples, as well as for mapping and seismic testing to determine the safety and integrity of the land at the dam and reservoir site.

The money will also help determine whether the proposed dam will actually provide the benefits its defenders promise, including helping improve salmon habitat on the Columbia River system.

Peterson has said numerous landowners along the river where a new dam and reservoir would be built still must be convinced of the project's merits.

What's more, environmentalists at Idaho Rivers United in Boise who have made a name for themselves calling for removal of four Lower Snake River dams to help boost salmon runs are casting a skeptical eye on this proposal. They say they'll look closely at what comes of the $2 million study before weighing in on whether a big new Weiser River dam is necessary.

"What's the real purpose and need for another expensive reservoir?" said Kevin Lewis, Idaho Rivers United policy director. "And what are the impacts to the Weiser River?"