A new study paints a worrying future for the Lake Powell reservoir.

Lake Powell, the second-largest man-made reservoir in the world built into the Colorado River, has experienced concerning levels of evaporation as drought conditions in the southwestern United States worsen. Aside from providing a source of clean water to local states, the reservoir also functions as a hydroelectric plant, supplying up to 5.8 million homes with power when operating at full capacity. According to a new study, if drought conditions persist, the reservoir may lose the ability to provide power.

According to the study, created by the US Bureau of Reclamation, this time next year there is a 3% chance that Lake Powell’s water supply could drop low enough to disable its hydroelectric capabilities. That chance jumps exponentially to 34% by 2023, assuming trends remain the same.

“The latest outlook for Lake Powell is troubling,” Reclamation’s Upper Colorado Basin Regional Director Wayne Pullan said in a news release. “This highlights the importance of continuing to work collaboratively with the Basin States, Tribes and other partners toward solutions.”

As of July, Lake Powell has dropped to 3,554 feet in elevation, a mere 33% of its total capacity, beating out the previous record set back in 2005. The nearby Lake Mead reservoir, which is the largest man-made reservoir in the world, isn’t faring much better, as its water supply bleeds off from runoff and evaporation. According to the Bureau of Reclamation, there is a roughly 66% chance that Lake Mead could drop below 1,025 feet below sea level by 2025. If this critical threshold is passed, California, Arizona, Nevada, and more would be forced to endure severe water cuts. There is also a roughly 20% chance that the level could drop below 1,000 feet, which is alarmingly close to the point at which water would stop flowing from the reservoir to Hoover Dam entirely.