A federal dam in Arizona that provides electricity to millions of Americans is at risk this year of running out of the minimum level of water required to generate that power.

Glen Canyon Dam, completed in 1963 and brought online two years later, is at 27 percent capacity, the lowest since it was filled, Bureau of Reclamation Commissioner Camille Touton told the Senate Energy and Natural Resources Committee Tuesday.

“The levels at Lake Powell, we are operating in conditions that we’ve never operated before,” Touton said.

The Colorado River Basin, which feeds Lake Powell and powers the Glen Canyon Dam, is in a 22-year drought. Due to human-caused climate change, Earth's atmosphere is warming, driving droughts to be more common and harsher, according to the NASA.

[In response to Western drought, a flood of legislation]

Touton’s testimony came a day after the National Oceanic and Atmospheric Administration said the U.S. experienced its fourth-warmest year on record in 2021, driven in part by the warmest December on record.

Citing a forecast the agency released last month, Touton said the levels of Lake Powell and Lake Mead, which powers the Hoover Dam, are both at historically low levels. The forecast projected Powell could drop below 3,525 feet by next month.

Lowest point

“This elevation is critical because it is just 35 feet above the minimum power production pool elevation of 3,490 feet,” Touton said in a written statement. That’s the lowest point at which Glen Canyon Dam can generate electricity.

“The continued extremely dry hydrology combined with already low reservoir levels means we are entering new and unpredictable operational conditions at Glen Canyon Dam, and other key facilities across the West,” she said.

Glen Canyon generates electricity for about 5.8 million people in Western states, according to 2019 figures from the bureau.

The agency announced last week it was changing its scheduled releases of water this year from the dam but would still release the same volume as part of an effort to maintain the minimum water level.

Asked by Sen. Martin Heinrich, D-N.M., how climate change was affecting the agency’s work, Touton said the bureau has installed new turbines that can operate at lower water levels, including at the Hoover Dam.

“When your fuel is based on water, you need to be able to look at it from both a water supply and also a hydropower perspective on how you keep those reservoirs up to protect both of those resources,” she said.

Sen. Mark Kelly, D-Ariz., aked about the potential Lake Mead could dry up  and trigger a shutoff of Hoover Dam.

“Current modeling does not project Lake Mead to decline to dead pool,” Touton said, “within the next five years.” 

The term “dead pool” describes the point at which turbines in a dam no longer turn.