US officials reject cool water release from Lake Powell to protect hydropower

Federal officials announced on 6 August 2026 that they will not release cool water this year from Lake Powell, a major reservoir on the Colorado River. The decision, communicated in an email by the Bureau of Reclamation, prioritises hydropower generation over measures to protect the humpback chub, a threatened fish species downstream of Glen Canyon Dam in northern Arizona.

The Bureau of Reclamation said the decision was made "due to significant hydropower generation concerns under already strained system conditions." Lake Powell is currently about 23% full, and the river downstream of the dam is approximately 69°F (20.5°C). The Bureau considers recommending cool water releases when downstream temperatures exceed 60°F (15.5°C) for three consecutive days, a threshold that has been regularly surpassed for over a month.

Cool water releases, known as "cool mix flows," involve releasing water from deeper, colder layers of the reservoir. These releases have been used in previous years to lower river temperatures and prevent the spawning of smallmouth bass, an invasive species that threatens the humpback chub. However, the deep water layers lack hydropower turbines, meaning such releases would reduce electricity generation.

The decision follows the worst snowpack on record for the Colorado River Basin, which supplies water to over 40 million people across seven US states, tribal nations, and Mexico. It also comes a week after federal officials proposed water cuts for California, Nevada, and Arizona to address the river's dwindling resources.

What the coverage left out

None of the digests from the left-rated outlets mentioned the specific temperature threshold the Bureau of Reclamation uses to consider cool water releases. The centre-rated KMGH report and the Associated Press report both included this detail. The right-rated digest did not mention the humpback chub by name or the species' threatened status.