Record low levels in the US’s second-largest water reservoir

Following a widespread and prolonged drought across much of the Colorado River Basin, millions of people in the southwestern US are at risk of water shortages due to low levels in Lake Powell, the second-largest water reservoir in the country.

This past winter, there was an unusually low snowfall, which has meant that the lake has not been replenished as usual, and is currently filled to only about 23 percent of its capacity. Apart from a few months in 2023, there has not been so little water there since 1965, the Utah State University writes in their report about the water supply crisis.

“What’s unique this year is that there was no recovery at all. What we expect to happen is that Lake Powell will go to unprecedented low conditions some time this fall,” said Jack Schmidt, the director of Utah State University’s Center for Colorado River Studies.

In early June, Lake Powell’s water levels were so low that it was just 48 metres from being considered a “dead pool”— the threshold at which the Glen Canyon Dam can no longer generate hydropower. On June 30, water levels in Lake Powell hit their lowest point of 2026. And water levels will continue to decrease every day for the remainder of the year.

“The Colorado system really is sort of a canary in the coal mine for climate warming stress,” said Dan Cayan, a climate researcher at the Scripps Institution of Oceanography at the University of California, San Diego.

“I think there are a lot of people and sectors that are extremely concerned right now because of these dwindling water supplies,” said Cayan. “There are certain threshold points on these big reservoirs, where you get below the point where you can deliver water, or whether water can be used for electrical generation, and there are things like that that are a great concern.” 

Authorities are now considering imposing restrictions on water use from Lake Powell, which supply water to 40 million people across seven US states.