Colorado River’s Water Release Decision Balances Hydropower and Conservation

Federal officials have decided not to release cool water from Glen Canyon Dam in Arizona this year, prioritizing hydropower production over conservation efforts for a threatened fish species downstream.

The Bureau of Reclamation communicated this decision in an email acquired by The Associated Press, citing significant concerns regarding hydropower generation amidst already strained system conditions. This choice highlights the ongoing challenges faced with overuse and climate change impacts on the Colorado River and its reservoirs.

The river’s dwindling supply affects farmers, industries, wildlife, and over 40 million people across seven U.S. states, tribal nations, and Mexico. The recent decision follows the worst snowpack on record for the Colorado River Basin and a federal proposal aimed at preventing a crisis with the resource. California, Nevada, and Arizona have been proposed to share water cuts.

“Cool mix flows” refer to the release of cold water from deep within a reservoir to temper the river’s temperature below. While beneficial in conservation, such releases would have compromised significant power generation as no hydropower turbines are located in those cool, deep sections. Lake Powell, at only 23% capacity due to extended use and rising temperatures, accentuates these challenges.

The warmer surface waters of Lake Powell pass through generators, drawing with them species like smallmouth bass, which then pose a threat to federally protected fish like the humpback chub further downstream. Previously, cold water releases in 2024 and 2025 successfully curtailed smallmouth bass spawning.

The river’s current temperature downstream from the dam stands at about 69 degrees Fahrenheit. The Bureau of Reclamation considers recommending cold water releases when temperatures exceed 60 F for three consecutive days, a threshold surpassed for over a month here.

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

Conservationists, like Matt Rice from American Rivers, expressed disappointment in the decision, emphasizing that cool mix flows are vital for mitigating smallmouth bass invasions in the Grand Canyon. He voiced concerns about the elevated temperatures threatening the nearby rainbow trout fishery and advocated for collaborative future solutions balancing environmental protection with human reliance on the river for power.

Utilities provided insights, noting the necessity of this decision for economic reasons, as alternative energy acquisitions could increase costs and are often less renewable. Andy Colosimo, of the Colorado River Energy Distributors Association, representing roughly 155 federal hydropower customers, supported the decision, acknowledging the complexity of the challenges faced.