The project was proposed by the U.S. Bureau of Reclamation, managers of Glen Canyon Dam; the National Park Service, which runs Glen Canyon National Recreation Area, encompassing Lake Powell, as well as Grand Canyon National Park; and the USGS, which operates the Grand Canyon Monitoring and Research Center, based in Flagstaff, Ariz.

According to an environmental assessment posted by the Bureau of Reclamation, the purposes of the project are "(1) to contribute to the conservation of endangered native fish, especially the humpback chub, by reducing populations of non-native fish who compete with and prey on native fish between Glen Canyon Dam and Lake Mead; (2) to conserve fine sediments that form sandbars, beaches and habitat for young native fish by altering dam operations; and (3) to improve the Lees Ferry sport fishery by reducing the overabundance of trout."

For the next year and a half, scientists from government agencies and universities will use on-site surveys and fly-overs to map the redistribution of sediment. They will sample water and test it by laser to measure the amount of silt.

The studies may help redesign outflows from the dam to better preserve and restore the region downstream, according to a press release by the bureau.

"Aerial photography will be complemented by channel-bed mapping and sediment classification," it adds. Remote sensing projects will start around Memorial Day 2008. Another set of checks 18 months from now will track changes in the river.

Meanwhile, the dam is putting on a spectacular show. "Big dams and lots of water coming of tubes in the bottom is always impressive," said Groat.

What's more encouraging, he said, is knowing that the experiment may improve the management of the river.

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E-mail: bau@desnews.com