Lake Mead sits just 9% above its minimum power pool after a record-low hydropower summer

Bathtub rings of bleached rock have become the signature of Lake Mead, and by the end of September the reservoir behind Hoover Dam had dropped to 1,038 feet, which the U.S. Energy Information Administration measured as 9% higher than minimum power pool. The margin is thin for a lake that supplies electricity as well as water. It arrived after a summer in which Southwest hydropower fell to record lows for the period.

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Between April and August, the region’s hydroelectric plants produced 19% less than in the same stretch of 2025 and about 28% less than their 10-year average, the agency reported on Nov. 13. Mead’s 9% buffer, by simple arithmetic, puts the floor near 950 feet, so the reservoir had roughly 88 feet of working room left on Sept. 30.

1,038 feet and what a 9% buffer buys

EIA’s Nov. 13 analysis says Lake Mead reached 1,038 feet by the end of September, 9% higher than minimum power pool. The reading was two feet under the 1,040 feet logged on Friday, Aug. 14, when the reservoir was about 27% full and below its 2022 record, according to the Post Independent’s tally of the Colorado River’s all-time lows. Mead was still sinking as autumn began, and the margin that remained is a fraction of what the reservoir held when it last set a record.

Powell is in a tighter spot. Reclamation figures reported by KSL put Lake Powell just under 30 feet above its own power floor of 3,490 feet in mid-August, a gap EIA says narrowed to less than 1% by the end of September.

Upstream scientists quoted by KSL framed the Colorado River’s risk in blunt terms. Jack Schmidt of Utah State University said the basin had entered uncharted territory, and Colorado State’s Brad Udall said Powell could reach its 3,490-foot threshold this year without extraordinary measures. Mead receives whatever Powell releases, so a reservoir hugging its own floor limits how much relief the lower lake can count on.

Hoover and Glen Canyon carry the Colorado’s power

KJZZ in Phoenix, covering the EIA note the day it appeared, reported that Hoover and Glen Canyon dams generate up to 90% of the hydropower on the Colorado River and that both set record-low output this summer. KJZZ added that 2026 output from the pair is on course to be the weakest in a decade or more, and that 2027 is expected to look much the same. A record-low summer is therefore a statement about two dams, and Hoover is the one fed by Mead.

Hydropower depends on both the volume released and the height of the water above the turbines. When the surface drops, each acre-foot passing through the dam carries less energy, so a lake that stays above its floor can still produce a record-low summer. Mead’s 1,038 feet shows that gap between staying online and producing at normal strength.

The federal framework behind Mead’s next two years

The Bureau of Reclamation announced emergency actions in April that included limiting Powell releases to the Lower Basin and drawing on Flaming Gorge Reservoir, and it released a final environmental impact statement for post-2026 operations managed in two-year increments through 2036, as the Post Independent reported. Because Powell’s releases feed Mead, decisions made upstream determine how fast the lower reservoir falls.

Andy Mueller of the Colorado River District said the framework keeps the basin “in a cycle of crisis management.” Arizona Gov. Katie Hobbs called the federal options “unacceptable.” Sarah Porter of Arizona State University’s Kyl Center for Water Policy described the document as “a decision-making framework,” not a plan. A Reclamation spokesperson said the agency and the Interior Department are working to keep both reservoirs above their critical elevations.

In plain terms, a 19% drop from 2025 means the region’s plants ran at about 81% of last year’s pace, and a 28% drop from the 10-year average means roughly 72% of normal. Those ratios cover every hydroelectric plant EIA counts in the Southwest, not only Hoover, but the Colorado’s two giants set the direction of the total. how unevenly the cushion is spread across the system. Mead’s 9% margin looks wide beside Powell’s less-than-1% margin, yet Mead was the lake that set its own low first, on Aug. 14, a day before Powell followed. Both reservoirs reached record lows within 24 hours of each other, and the percentages EIA reported for the end of September describe two lakes still in decline.

EIA’s generation forecasts appear in its monthly Short-Term Energy Outlook, where hydropower expectations for the Southwest would be revised if the reservoirs keep falling.

The unanswered question is how far Mead falls before spring runoff. The 1,038-foot figure is an end-of-September reading, and no reading from November is in the EIA note, so the agency’s 9% cushion is a snapshot of where the lake stood when the record-low summer ended.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.