Lake Powell sits just 28 feet above turbine shutdown level as water releases remain limited

The U.S. Bureau of Reclamation reported that Lake Powell’s elevation reached 3,517.85 feet on Sept. 2, providing a narrow 27.85-foot margin above the 3,490-foot minimum power pool where the dam’s eight turbines are shut down. The 710-foot concrete Glen Canyon Dam can generate up to 1,320 megawatts when water flows through the penstocks, but the agency stops turbine operation 20 feet above the intakes to avoid cavitation damage to the steel equipment.

A 2024 technical memo indicates the official lake gauge ends at 3,477.5 feet, the top of the penstocks, meaning the current water level is only about 40 feet above the point for which the original design had no measurement. Below the turbines, four 96-inch outlet valves at 3,374 feet can release roughly 15,000 cubic feet per second, but a 2023 high-flow test showed cavitation erosion in these pipes, and the agency cautioned against relying on them for sustained releases.

Lake Powell set a new record low in August, surpassing the previous low of 3,519.92 feet recorded in April 2023. In July, inflow to the reservoir was only 9 percent of average, while releases downstream totaled 482,000 acre-feet. To keep the lake above the shutdown line, the Bureau reduced water deliveries to Lake Mead and opened Flaming Gorge Dam on the Green River, diverting up to 1 million acre-feet of water toward Powell through April 2027. The exact amount of water that has reached Powell is not publicly tracked.

Projections from the agency’s 24-month study forecast the lake falling below 3,540 feet by Oct. 1 and dropping under 3,510 feet sometime in water year 2027, even with the Flaming Gorge contributions. Future releases from Powell are expected to range between 6.0 and 7.0 million acre-feet under the Low Elevation Infrastructure Protection Range operating rules.