The Interior Department gave its final OK late Friday for an experiment next week that involves an extremely high-flow release of water through the Glen Canyon Dam in an effort to learn whether the method can be used to rebuild eroded beaches downstream on the Colorado River.

Next Wednesday the Bureau of Reclamation will release water from the dam's power plant and bypass tubes at a rate of about 41,000 cubic feet per second for about 60 hours for a total of almost 8.23 million acre-feet of water. Similar releases since 1996 have been at a rate of between 8,000 and 20,000 cubic feet per second.

The increased rate of water being released is expected to change river conditions and the availability of campsites along the river. After the release, scientists will study the impact on habitat in and around the river.

Already experts agree that more sand is needed to rebuild sandbars along the river's 277-mile stretch through the Grand Canyon National Park. The release will also create backwater habitat used by young humpback chub and other native and nonnative fish.

The Interior Department based its final decision on the results of an environmental review process required by the National Environmental Policy Act and the Endangered Species Act.