FLAGSTAFF, Arizona (AP) – Federal officials say it may be necessary to reduce water supplies to users on the Colorado River to prevent the closure of a huge dam that supplies hydropower to about 5 million customers in the western United States.
Officials had hoped snowmelt would cushion Lake Powell on the Arizona-Utah border to ensure its dam could continue to supply power. But the snow is already melting, and warmer temperatures than usual and prolonged drought are shrinking the lake further.
The Department of the Interior has proposed keeping the water back in the lake to maintain Glen Canyon Dam’s ability to generate electricity in the midst of what it said were the driest conditions in the region for more than 1,200 years.
“The best available science indicates that the effects of climate change will continue to adversely affect the basin,” wrote Tanya Trujillo, the interior secretary’s assistant secretary of water and science to seven states in the basin on Friday.
Trujillo asked for feedback on the proposal to keep 480,000 acres of water in Lake Powell – enough water to serve about 1 million American households. She stressed that the operation of the dam below 3,490 feet (1,063 meters), considered its minimum current pool, is unknown territory and will lead to even more uncertainty for the western power grid and water supplies to states and Mexico downstream.
In the Colorado River Basin, Glen Canyon Dam is the mammoth of power generation, supplying electricity to about 5 million customers in seven states – Arizona, Colorado, Nebraska, Nevada, New Mexico, Utah and Wyoming. As Lake Powell falls, the dam becomes less efficient. At 3,490 feet, it can not produce power.
If levels were to fall below this mark, the 7,500 residents of the town by the lake, Page and the adjacent Navajo community LeChee would not have access to drinking water.
Pacific Northwestand the Rio Grande Valley in New Mexico and Texas face similar strains on water supply.
Lake Powell fell below 3,525 feet (1,075 meters) for the first time ever last month, a level that worried water managers. Federal data shows it will fall even more, in the most likely scenario, before returning above the level next spring.
If power outages cease at Glen Canyon Dam, customers including towns, rural power cooperatives and tribal corporations will be forced to seek more expensive options. The loss would also complicate Western grid operations since hydropower is a relatively flexible renewable energy source that can be easily screwed up or down, experts say.
“We are in crisis management, and health and human safety issues, including hydropower production, take precedence,” said Jack Schmidt, director of the Center for Colorado River Studies at Utah State University. “Concepts like ‘Shall we get our water back’ may not even be relevant anymore.”
The potential effects for lower basin states that could see their water supplies reduced – California, Nevada and Arizona – are not yet known. But the interior features are a display of the far-reaching features of Lake Powell and Glen Canyon Dam, and the need to turn quickly to confront climate change.
Lake Powell serves as the barometer of river health in the upper basin, and Lake Mead has that job in the lower basin. Both were last filled in the year 2000, but have dropped to a quarter and a third, respectively, of their capacity as the drought tightened its grip on the region.
Water managers in the basin states – Arizona, California, Nevada, Utah, Wyoming, New Mexico and Colorado – are evaluating the proposal. The Interior Ministry has set a deadline for feedback on April 22nd.
Associated Press writer Sam Metz of Salt Lake City contributed to this report.