A handful of massive, ancient fish species could emerge as the unlikely winners from the record-setting drought gripping the Colorado River that has sent states, farmers, cities and the federal government scrambling.
The Trump administration announced Friday that it is planning to release an enormous amount of water from a reservoir upstream of Lake Powell as part of its emergency plan to head off a water and power disaster along the West’s most important river.
To get to Lake Powell, that water must travel from Flaming Gorge Reservoir along the Utah-Wyoming border through a stretch of Utah’s Green River that is home to four species of endangered fish. Environmental advocates say that if the Interior Department times those releases to strategic periods of year, they could provide a major boost to the fish populations.
“In an otherwise terrible water year, let’s get some good out of it and benefit these endangered fish,” said John Berggren, a regional policy manager with the group Western Resource Advocates.
It would be a small but notable move from the Trump administration, which recently invoked an obscure provision of the Endangered Species Act to override protections for imperiled animals in the Gulf of Mexico in the name of oil and gas production.
The Interior Department’s Bureau of Reclamation declined to comment on the plans. But Reclamation has posted public documents that indicate it is planning to deliver the water in a way that largely lines up with fish advocates’ requests. Those plans were reiterated by agency staff during a Flaming Gorge working group meeting Tuesday.
States that have been warring over the management of the Colorado River, which supplies 40 million people from the mountains of Wyoming to Phoenix and Los Angeles, appear to be largely agnostic. They also have a self-interest in helping the species, since the network of dams and canals that they rely on must remain in environmental compliance.
“We have heard that green groups would like to see any releases from the [upstream reservoirs] be timed to maximize benefits to spawning, but that’s outside our level of expertise,” Doug MacEachern, a spokesperson for the Arizona Department of Water Resources, said by email. “We are very much focused on maximizing the volume of releases.”
The fish at issue — the razorback sucker, Colorado pikeminnow, humpback chub and bonytail — evolved along a very different river, before humans tamed and siphoned its flows.
That earlier river swelled each spring with snowmelt that flooded wetlands and other marshy habitats, connecting to the river’s main stem during only short periods of the year. Those backwater areas served as a vital refuge that allowed larvae and juvenile fish to grow in areas protected from predators.
Now, fish advocates, including a recovery program run by the FWS, hope that the extra water could be put to use to mimic those natural conditions.
Interior said it is planning on releasing between 660,000 and 1 million acre-feet of water out of Flaming Gorge this year, and the public documents indicate that it is considering delivering a good gush of that water in the coming weeks, which would roughly match the timing of those spring floods.
That would be particularly beneficial for the razorback sucker, a giant of a fish that can grow to be 3 feet long and live up to four decades, said Joe Trungale, senior freshwater scientist with The Nature Conservancy.
“Razorback spawn on the ascending limb of the peak flow,” he said. “The larvae drift in the river and try to find backwater sections to grow from a larvae to juvenile fish that can move itself around.”
In 2022, Reclamation made a similar emergency move, releasing approximately 500,000 acre-feet of water from Flaming Gorge.
That year, when biologists did their fish count, they found nearly as many fish in that one year as they had found in total over the previous decade.
“A lot of fish ended up in these off-channel wetlands and we ended up getting record numbers of razorback sucker coming out of the wetlands at the end of the summer,” said Trungale. “We had bigger and more fish than we’ve really ever seen in the history of the recovery program.”
But it’s not just about mimicking spring floods. When the Upper Colorado River Endangered Fish Recovery Program — a program run by the FWS in partnership with states, water users and environmental organizations — sent a request to Reclamation in December, the top priority was to have a spike of cold water delivered during a different window of time in the spring that would disrupt smallmouth bass nesting. The nonnative bass are a major predator of the endangered fish.
The program also asked for a higher summer base flow, which would be particularly beneficial for the pikeminnow.
Environmental groups say they are largely pleased with the tentative plan Reclamation has posted, although they’d like to see more flows happen earlier and a larger base flow, rather than sending that water during the fall and winter when it has little benefit to the fish.
But it’s not all good news for the river’s fish.
Federal biologists are scrambling to keep a robust population of smallmouth bass from establishing in the Grand Canyon, where they are also trying to recover razorback sucker and humpback chub. Those efforts have hinged on delivering blasts of cold water out of Lake Powell to disrupt bass spawning in the canyon.
As the water levels at Lake Powell fall, however, the water delivered out of Glen Canyon Dam becomes warmer, which could instead help the invasive species’ breeding.
Even more concerning is the fact that those falling water levels also stand to make it more likely that the bass living near the surface in Lake Powell will find their way through the hydropower turbines and head downstream, said Taylor McKinnon with the Center for Biological Diversity. His group has criticized Reclamation for not moving faster to install fish barriers at the dam.
“Absent fish barriers that BOR has diligently contemplated now for more than a decade, this year will be a huge entrainment event,” McKinnon said by email.
