The water level at Lake Powell, the massive reservoir on the Colorado River whose southern reaches straddle the Utah-Arizona border, hit a record low this week, sinking to just 3,522 feet above sea level. A 23-year megadrought combined with climate change has left the reservoir at just 22 percent of its capacity—so low that it threatens to cause the collapse of a water supply system serving 40 million people throughout the arid west.
“It may soon become physically impossible to pass enough water through.”
Created by the 1963 construction of the Glen Canyon Dam, Lake Powell is the nation’s second-largest reservoir. Over the past year, federal officials have ordered emergency water releases from upstream reservoirs, such as Utah’s Flaming Gorge, to prop up the lake and keep the dam’s turbines turning and providing electricity. While this year’s above average snowpack may help, even the Bureau of Reclamation, which historically has wildly overestimated the Colorado River’s flow, expects Lake Powell to drop another 30 feet by September.
One underappreciated element of this looming crisis is Glen Canyon Dam itself. If the water level in Lake Powell falls another 150 feet from its current level, the reservoir will hit dead pool, meaning that the Colorado River will no longer run through the dam, stopping flow to booming populations in Arizona and Nevada, as well as to Mexico and the agricultural areas of California’s Imperial Valley.
“Lake Powell is quickly approaching the point at which it may soon become physically impossible to pass enough water through the dam,” warned an August report by regional environmental groups. “Such an event would likely be the most calamitous in the Colorado River System’s history, causing legal complications, economic harm, and a water supply crisis across the seven states and Mexico.”
Environmentalists have long hated the Glen Canyon Dam, which submerged beautiful canyons, caused environmental degradation, and harmed endangered fish in the Grand Canyon. Edward Abbey’s landmark novel The Monkey Wrench Gang was based on a plot to blow up the structure.