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In the struggling Colorado River basin, where water is scarce, the White House has signaled its priorities for how to use the remaining gallons.
Even as scientifically-determined thresholds have been met for releasing water from Glen Canyon Dam for ecological and recreational benefits in Grand Canyon, the Trump administration has decided against those actions in this record-hot year – deciding not to release cold water from deep in Lake Powell to aid the humpback chub, a threatened fish species, and not to authorize a high-volume release of water to rebuild Grand Canyon’s eroded beaches, which are in terrible condition, according to federal monitoring.
These environmental releases would not change the total volume of water flowing out of Lake Powell over the year, just the timing.
Because the releases bypass the dam’s turbines and reduce hydropower generation, which is part of the administration’s “energy dominance” agenda, the Bureau of Reclamation, the federal agency that manages Glen Canyon Dam, will not be doing them.
“After evaluating management alternatives and considering all authorized purposes, the decision was made based on significant hydropower generation concerns under already strained system conditions,” Reclamation said in a statement in August.
The administration’s decisions foreshadow more difficult choices ahead. Due to climate change and overuse, the Colorado River is shrinking and warming. Its dams were built and river management goals were laid out during an era that anticipated healthy reservoirs. That is no longer the case. Because Lake Powell and Lake Mead are about a quarter of their capacity or less, the hydrological assumptions that inform current management strategies are outdated, said Jack Schmidt, a scientist who has spent his four-decade career studying the Colorado River.
“Everything needs to be revisited because the driving factors of the Colorado River ecosystem in Grand Canyon are now completely changed and probably forever changed,” said Schmidt of Utah State University’s Center for Colorado River Studies. “Everything was developed in a world of full reservoirs. And now the reservoirs are empty.”
Tradeoffs Plague Water Managers
Even in the best of times, managing a large dam on a major river is not easy. Dams alter the river’s natural patterns of flow and temperature. Operators must weigh one set of benefits against another group of costs.
Glen Canyon Dam is one of the thorniest management conundrums. Located near the Arizona-Utah border, the 63-year-old structure has emerged as the most significant water-supply choke point in the Colorado River basin and it is the focus of clamorous debate about water and power infrastructure in a drier climate.
As managers grapple with how much water to release, Glen Canyon Dam is also choking the river of its natural supply of sediment. Without new inputs, sand bars and beaches in Grand Canyon are at risk of disappearing. These features provide habitat, give boaters a place to camp during river trips, and protect archaeological sites.
Most of the river’s sediment now comes from the Paria River and Little Colorado River, downstream of Glen Canyon. Periodic high-flow water releases from the dam mimic the thunderous floods of the past that carried sediment through Grand Canyon to fortify eroding beaches.
There is enough sediment in the Colorado River below Glen Canyon today to warrant a high-flow release. Yet Reclamation has not done one since 2023. Experts agree that Reclamation is highly unlikely to conduct one this fall either. A final decision will be made in the next few weeks.
The need for a high-flow release is mounting. In August, David Topping, a research hydrologist at the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center, presented data showing the ill health of Grand Canyon beaches. A typical sand bar is smaller now than in 2016, when the current management plan that established the high-flow triggers was finalized.
The lack of high-flow releases has deprived researchers of crucial data on how the size and duration of these mini-floods, usually one to four days in length, aid beach-building.
“What can we do if the administration isn’t willing to allow us to use the bypass tubes for high-flow experiments, if that’s going to be off the table, at least for a while?” said Wayne Pullan, Reclamation’s Upper Colorado Region director, at a Glen Canyon management meeting in August, asking attendees to consider management options under political constraints.
“We’re in a pinch point,” Pullan added. “A real pinch point.”
Degraded beaches result in a degraded river experience, said David Brown of the Grand Canyon River Guides, a recreation advocacy group. Rafting groups have to compete for limited real estate in what is generally regarded as one of the world’s premier river corridors.
“When there’s less campable area, that means everyone’s kind of getting squished together or your toilet is next to where people are sleeping,” Brown said.
Non-Native Species Thrive in Warm Water
In addition to sediment, water temperature is the other blinking red environmental indicator.
Air temperature records in the basin are being obliterated this year. Colorado, home to the river’s headwaters, had its hottest summer ever. Scorching air temperatures are reflected in water. The Colorado River below Lake Powell is the warmest since Glen Canyon Dam was completed.
Smallmouth bass were introduced as a sport fish in the upper Colorado River basin in the late 1960s. Voracious feeders, smallmouth bass view other fish as the sport, happily preying on threatened native species like the humpback chub, an eighteen-inch fish in Grand Canyon with a distinctive smooshed silhouette.
Listed as endangered in 1967, the humpback chub has now bounced back thanks to tens of millions of dollars of conservation investment. The U.S. Fish and Wildlife Service upgraded the humpback chub to “threatened” status in 2018.
Smallmouth bass live in Lake Powell, preferring the layer of warm water closest to the surface. As the lake shrinks, that warm layer has now reached the level of the penstocks, which pull water into Glen Canyon Dam’s turbines for hydropower generation before being released downstream.
In these low-water conditions, the fear is that more smallmouth bass will be delivered into the Colorado River below Glen Canyon.
Once there, they will find a habitable environment. Smallmouth bass spawn when water temperatures exceed 60 degrees Fahrenheit. This year, that mark was breached in June. Today, the river at Lees Ferry, about 16 miles downstream of Glen Canyon Dam, is about 70 F.
These conditions – when the river temperature is above 60 F for three consecutive days – are supposed to trigger a release of cold water from deep in Lake Powell. The U.S. Fish and Wildlife Service says that this “cool mix” is the “only conservation measure proven to limit smallmouth bass reproduction.” Evidence from cool mix releases in 2024 and 2025, which knocked down smallmouth bass numbers, supports that conclusion.
Cool mix, however, will not happen in 2026 due to the Trump administration’s desire to generate hydropower.
The last cool mix flow, in 2025, cost the Western Area Power Administration, which markets federal hydropower, $6.1 million to replace that electricity for its contractors.
Instead of cool mix, Reclamation says it is focusing on other options to keep smallmouth bass from establishing downstream of Glen Canyon and to preserve the humpback chub’s hard-won conservation gains. In the short term that means stunning the bass with electric-shock tools and physically removing them from the water.
In the longer term, Reclamation is considering installing infrastructure to regulate the temperature of the water that passes through Glen Canyon. The agency calls this one of its “durable structural solutions.”
An Uncertain Future
Cool mix and high-flow releases are an attempt to rebalance an ecosystem that the dams destabilized. Congress passed the Grand Canyon Protection Act of 1992, which orders Reclamation to operate Glen Canyon Dam in a manner that protects and reduces harm to the “natural and cultural resources and visitor use.” That is, fish, tribal archaeological sites, and rafting.
The act required an environmental impact statement for Glen Canyon Dam that would analyze the actions required to achieve the broad environmental-protection goals set by Congress.
It was a “compromise to really put all the resources on the same playing field,” said Jen Pelz of the Grand Canyon Trust. In her view, decisions this year tilt in one direction – hydropower. “I don’t feel like they’re being balanced right now.”
Because the river guides were instrumental in lobbying for Grand Canyon protections, the present-day failures to uphold the act’s goals are all the more galling, Brown said. “It’s very hard to watch it get ignored.”
The administration is prioritizing hydropower when hydropower is at a pivot point.
Generation at Glen Canyon is down more than 40% from when Lake Powell was full. Utilities are turning to solar and wind to cover some of the generation losses, while utility-scale batteries are helping to replace the capacity and grid-regulating functions that a large dam provides.
The decision to favor hydropower over ecology reflects bigger problems with the Colorado River’s infrastructure. Glen Canyon Dam is not designed for the river as it exists today. Reclamation wants to keep Lake Powell high enough to generate hydropower because the dam’s other outlets to deliver water downstream are untested over long periods and were damaged in a previous high-flow release.
Lower basin states and tribes, including Arizona, California, Nevada, and the Gila River Indian Community, have asked the federal government to update Glen Canyon’s infrastructure for water delivery and power generation. Reclamation is assessing three options and expects that study to be released in early 2027. Any additional action will require congressional approval and funding.
Along with the infrastructure problems, man-made climate change is sapping the river and heating up its water. Ecologists consider the Grand Canyon a “novel ecosystem,” meaning its native species and natural processes have been disrupted and rearranged by human meddling.
To Schmidt, the former chief of the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center, this suggests a wholesale rethinking not just of the river’s infrastructure but also of our ecological goals for the Colorado River.
“We as a society get to play God in deciding what attributes of that ecosystem we value, which ones we want to work hard to preserve and which ones we don’t,” he said. “The answer is not an obvious one.”
This story was produced by Circle of Blue, in partnership with The Water Desk at the University of Colorado Boulder’s Center for Environmental Journalism.
For full Colorado River basin coverage, visit our Colorado River page.
