After years of severe drought compounded by climate change, the water level in Lake Powell, the second-largest reservoir on the Colorado River, has dropped to just 24% of full capacity and is continuing to decline to levels not seen since the reservoir was filled in the 1960s.
In effort to boost the shrinking reservoir, the federal government announced Tuesday that it plans to hold back water to reduce risks of the lake falling below a point at which Glen Canyon Dam would no longer generate electricity.
“Today’s decision reflects the truly unprecedented challenges facing the Colorado River Basin and will provide operational certainty for the next year,” Tanya Trujillo, the federal Interior Department’s assistant secretary of water and science, said in a statement announcing the measures.
It is the first time that the U.S. Bureau of Reclamation has invoked its authority to change its operations at Glen Canyon Dam on the Arizona-Utah border. The agency said the plan protects the dam’s ability to generate hydropower and the facility’s infrastructure and will ensure water supplies continue to be available for the nearby city of Page, Arizona, and a portion of the Navajo Nation.
The federal government’s plan aims to reduce the risks of Lake Powell falling to critically low levels. The measures will involve releasing about 500,000 acre-feet of water from Flaming Gorge Reservoir, which is located upstream, and leaving an additional 480,000 acre-feet in Lake Powell by reducing the volume of water released from Glen Canyon Dam this year.
For comparison, California, Arizona and Nevada used 6.8 million acre-feet of Colorado River water in 2020.
David Palumbo, the bureau’s acting commissioner, praised the quick response and support by the seven states that depend on the river. He said while carrying out these short-term actions, “we recognize the importance of simultaneously planning for the longer-term to stabilize our reservoirs before we face an even larger crisis.”
The federal government last month proposed the plan to combat declines in Lake Powell to the states in the Colorado River Basin.
In a letter, Trujillo asked the states for their input on the plan.
“We believe that additional actions are needed to reduce the risk of Lake Powell dropping” below a level of 3,490 feet above sea level, Trujillo said in the letter.
Trujillo warned that below the threshold of 3,490 feet, Glen Canyon Dam’s facilities face “unprecedented operational reliability challenges, water users in the Basin face increased uncertainty, downstream resources could be impacted, the western electrical grid would experience uncertain risk and instability.”
The level of the reservoir on the Arizona-Utah border now stands about 32 feet above that threshold.
“We are approaching operating conditions for which we have only very limited actual operating experience,” Trujillo said in the letter.
Representatives of the seven states responded in a letter April 22, saying they agreed that “additional cooperative actions should be taken this spring to reduce the risk of Lake Powell declining below critical elevations.”
The state officials said they supported the government’s plan to release less water from Lake Powell “to reduce the risks we all face.”
The Colorado River supplies water to nearly 40 million people in cities from Denver to Los Angeles and to farmlands from the Rocky Mountains to the U.S.-Mexico border. The river has been chronically overused, and its reservoirs have fallen dramatically since 2000 during a severe drought that scientific research shows is being intensified by global warming.
Trujillo said everyone who relies on the river “must continue to work together to reduce uses and think of additional proactive measure we can take.”
