From Yale Environment 360:
Dwindling water levels at Lake Powell could make it impossible for its dam to generate hydropower in 2023, according to new projections from the U.S. Bureau of Reclamation.
Lake Powell, the second-largest human-made reservoir in the United States, stretches from northern Arizona into southern Utah on the Colorado River. With severe heat and persistent drought sapping the river, water levels at Lake Powell fell to 3,554 feet this summer, the lowest level on record. If trends continue, there is a 34 percent chance that, in 2023, water levels could dip below 3,490 feet, the minimum needed to produce hydropower at the Glen Canyon Dam, the bureau said. The dam supplies power to 5.8 million customers.
“The latest outlook for Lake Powell is troubling,” Wayne Pullan, the bureau’s Upper Colorado Basin regional director, said in a statement. “This highlights the importance of continuing to work collaboratively with the Basin States, Tribes and other partners toward solutions.”
At Lake Mead, further down the Colorado River, there is 22 percent chance that in 2025 water levels will dip below 1,000 feet, close to the level where water can no longer flow through the Hoover Dam, the bureau said. Drought has already limited hydropower in other parts of the West. In August, officials shut down the Hyatt Power Plant at Lake Oroville in northern California after water levels dropped near the minimum needed to generate electricity.
The Colorado River’s flow has fallen roughly 20 percent over the last century, and rising temperatures are responsible for more than half of that decline, according to a 2020 study. The region is now enduring its worst drought in 1,250 years, fueling a crisis on the river. With water supplies growing increasingly scarce, some have called for draining Lake Powell — and shutting off the Glen Canyon Dam — to supply more water to Lake Mead downstream.