AZL General Discussion, page-2465

What are your plans when the power goes out? But the water supply won't last that long, anyway.

Glen Canyon Dam's generating turbines are powered by water in Lake Powell, the declining Colorado River reservoir that straddles the Arizona-Utah line and relies largely on Rocky Mountain snowmelt. It churns out part of the power supply for about 5 million people across six of the seven states in the river’s watershed, excluding California.

If the reservoir’s surface drops below 3,490 feet above sea level, the dam’s turbines can no longer produce any power. The water is currently at about 3,547 feet, a record low that keeps falling. The new projections show there is a 90% chance Powell will decline to elevation 3,525 feet next year, a level that gives the bureau a buffer to protect the dam's operations.

–Arizona Republic 9/23/21