Key facts
- Federal officials will not release cool water from Lake Powell this year.
- The decision is due to concerns about hydropower generation and strained system conditions.
- The cool water release is intended to protect the threatened humpback chub.
- Lake Powell's low water levels are attributed to overuse and climate change.
- Invasive smallmouth bass spawning in warm water poses a threat to native fish.
- Utilities expressed satisfaction with the decision, citing cost savings on alternative energy.
Federal officials have decided against releasing cool water from Lake Powell this year, a measure intended to protect the threatened humpback chub downstream. The Bureau of Reclamation cited significant concerns over hydropower generation under already strained system conditions as the reason for the decision. Lake Powell, a major reservoir on the Colorado River, is currently at only 23% capacity due to overuse and climate change, leading to warmer surface water temperatures.
The decision creates a conflict between conserving native fish and maintaining electricity production. The "cool mix flow" involves releasing cold water from the reservoir's depths, which bypasses hydropower turbines, thus reducing power generation. This year's decision comes after a record-low snowpack in the Colorado River Basin and follows a recent federal proposal to address the river's crisis.
Invasive smallmouth bass, introduced for sport fishing, thrive in the warm surface waters of Lake Powell and can spawn when temperatures are high, posing a threat to the humpback chub and other protected species. Officials noted that cool water releases in 2024 and 2025 had successfully prevented smallmouth bass spawning. The river downstream of Glen Canyon Dam has regularly exceeded 60°F (15.5°C) for over a month, a threshold that typically prompts recommendations for cold water releases.
Conservation groups expressed disappointment, with American Rivers stating that the decision was not unexpected but still concerning for the humpback chub. They highlighted that cool mix flows are the most effective method to mitigate the smallmouth bass invasion in the Grand Canyon. Utilities that purchase hydropower from Glen Canyon Dam welcomed the decision, estimating that releasing cool water would have forced them to spend millions on more expensive alternative energy sources and potentially increase customer electricity bills.