By Ken Ritter, The Associated Press

LAS VEGAS — The federal government is committing to at least another 20 years of use of a huge Colorado River dam that officials call crucial to states in the West, but that critics say is unstable and should be removed.

“Politics belong out of this, because water is life,” said U.S. Interior Secretary Sally Jewell at a conference of key water managers in Las Vegas. She signed an agreement that allows the federal Bureau of Reclamation to manage Glen Canyon Dam and the Lake Powell reservoir in Arizona through 2036.

The agreement “provides certainty and predictability to those that use water and power from the dam,” Jewell said, while also providing environmental protection for fish and wildlife in the Grand Canyon, through which the dam sends water to Lake Mead and Hoover Dam near Las Vegas.

Critics call Glen Canyon Dam obsolete and Lake Powell too porous and wasteful to keep operating in a basin.

Glen Canyon Dam, completed in 1964 near Page, Arizona, is the second-tallest concrete-arch dam in the United States, behind Hoover Dam near Las Vegas. But while Hoover Dam is anchored in solid volcano-baked basalt, Glen Canyon Dam spans a gorge lined with Navajo sandstone that critics compare with hardened sand dunes.

“Lake Powell is evaporating and seeping hundreds of thousands of acre-feet per year that are completely lost to the (Colorado River) system,” said Gary Wockner, executive director of the Denver-based group Save the Colorado. He called Jewell’s decision “an extraordinary waste.”

“In order to keep the lake level high enough to keep electric turbines spinning, they’re going to have to buy massive amounts of water from farmers in Colorado and Utah,” Wockner said.

Glen Canyon has eight hydroelectric turbine generators that the Bureau of Reclamation says produce about 5 billion kilowatt-hours of hydroelectric power per year for distribution by the Western Area Power Administration to Nebraska and six of seven Colorado River basin states.

U.S. Rep. Rob Bishop, R-Utah, chairman of the House Committee on Natural Resources, accused Jewell of “making long-term decisions before the clock runs out” on President Barack Obama’s administration.

Bishop said the plan shortchanges hydropower in favor of fish, and he predicted communities and states that rely on cheap hydropower will suffer.

Jewell told reporters the agreement received five years of study about economic, technical, social and environmental factors, and was supported by states, the National Parks Conservation Association, Western Area Power Administration, the Navajo Nation and six other tribes, Grand Canyon river rafting groups and the public.

She said the so-called Long-term Experimental and Management Plan won’t change water allocations for the basin states — Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming — or Mexico.

But drought might. Jewell spoke several times of a 50-50 chance that a drought declaration will be made next August, forcing cuts in water deliveries beginning in January 2018 to Arizona and Nevada.

Under various treaties, regulations, statutes and agreements including the Colorado River Compact of 1922, seven states are promised a share of about 15 million acre-feet of water the river was projected to take in annually from rainfall and snowmelt. Drought has cut that figure, and officials acknowledge the available supply today falls short of promised amounts.

Anne Castle, a former assistant Interior Department Interior secretary who spent years working on Colorado River issues and now heads a research program at the University of Colorado, called the decision that Jewell signed important for the West. She said revenue from power produced at the dam pay for endangered species, environmental management and reclamation programs.