Federal Officials Opt Against Cool Water Release to Protect Hydropower Amid Colorado River Challenges

Federal authorities have determined not to release cooler water from one of the key reservoirs of the Colorado River this year. This decision aims to preserve hydropower generation at the expense of the threatened native fish downstream.

The Bureau of Reclamation, through an email retrieved by The Associated Press, informed various groups about their choice to withhold water release from Glen Canyon Dam in northern Arizona. The decision was made due to significant concerns related to hydropower generation amidst already strained system conditions.

This decision juxtaposes the preservation of the humpback chub, a fish native to the Colorado River, against the escalating electricity costs for consumers. As the river and its reservoirs continue to diminish due to overconsumption and climate change, officials found themselves having to choose between conservation efforts and power generation.

After experiencing the worst snowpack recorded in the Colorado River Basin, which serves farmers, industries, wildlife, and over 40 million individuals across seven U.S. states, tribal nations, and Mexico, federal officials have stepped up. They have proposed a crisis-averting strategy after the states dependent on the river—California, Colorado, Arizona, Nevada, New Mexico, Wyoming, and Utah—failed to agree on resource sharing for the long term. Under this proposal, California, Nevada, and Arizona are expected to share water cuts.

The concept of a “cool mix flow” involves the release of cold water from the depths of a reservoir, like Lake Powell, to lower the temperature of the river downstream. However, there are no hydropower turbines in these cooler, deeper sections, which would entail significant power generation loss.

Currently, Lake Powell stands at approximately 23% capacity following years of excessive use and evaporation. With rising average temperatures due to climate change, warm surface water is drawn through generators and directed downstream. The presence of smallmouth bass, utilized in Lake Powell for sport fishing since the 1980s, compounds the issue. These fish and their potential spawning pose a threat to the humpback chub and other protected fish species further south on the river. Previous releases of cool water in 2024 and 2025 successfully thwarted smallmouth bass spawning efforts.

Wayne G. Pullan, regional director of the Upper Colorado Basin, stated in an email, “Our efforts this year will focus on expanded rapid response removal actions, additional backwater modifications, evaluation of innovative tools, and advancement of durable structural solutions.”

Matt Rice, director of the southwest region for American Rivers, expressed that while the decision was anticipated, it remains disappointing. He underscored that cool mix flows have proven effective against the smallmouth bass invasion in the Grand Canyon and hoped the decision would not spell disaster for the humpback chub. He also pointed out the risks posed to the nearby rainbow trout fishery due to elevated temperatures.

Utilities purchasing hydropower from Glen Canyon Dam argued that the release would necessitate spending millions on alternative energy sources that are both costly and potentially less renewable, thereby inflating electricity bills for customers. Andy Colosimo, Executive Director of the Colorado River Energy Distributors Association, which represents roughly 155 hydropower customers, praised the decision. “I think this was the right call, given the conditions that we’re all facing.”

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