New projections by the U.S. Bureau of Reclamation found that falling water levels at the country’s second-largest reservoir could prevent the lake’s dam from producing hydropower as soon as next year. The modeling shows a 34 percent chance that water levels in the lake, which is located on the Colorado River from northern Arizona to southern Utah, could drop below the minimum needed to allow the lake’s dam to generate electricity in 2023. When running at full capacity, the dam produces power for around 5.8 million customers from Nebraska to Nevada. Nearby Lake Mead, the nation’s largest reservoir that is also fed by the Colorado River watershed, has also been draining at an alarming rate.

Projections show a 66 percent chance that Lake Mead drops below a threshold that would trigger deep water cuts for millions in the U.S. west. The Colorado River Basin, which serves 40 million people in the American West, is the middle of a climate-change-fueled megadrought that has stretched on for more than 20 years. (AP, CNBC, CNN, Gizmodo, Daily Mail, Independent, Climate Signals background: Drought)