March 28, 2026
- The Colorado River Basin is home to four endangered or threatened fish species found nowhere else on Earth.
- These fish depend on a dynamic and interconnected river habitat fueled by melting snow, but dams, water diversions, drought, and climate change have reshaped the river.
- The Bureau of Reclamation is working on a plan to send additional water downstream to stabilize levels in one of the river’s major reservoirs. Smart timing of this operation could provide water to help native fish survive.
Spend the day on the Colorado River and you might be lucky enough to spot a 40-year-old fish that is found nowhere else on Earth — a fish that was alive when people were lining up outside theaters to see “Top Gun” (the original one) and heading to record stores to pick up Whitney Houston’s debut album.
The river is home to four endangered or threatened fish species that are found only in the Colorado River Basin. These fish evolved 3 to 5 million years ago — long before dams, pipelines, and climate change reshaped the river. They depend on dynamic, interconnected river habitat fueled by melting snowpack.
Meet the Fish#
Bonytail
(Gila elegans)#
Endangered#
Bonytail is one of the river’s great mysteries. This fish is so rare that little is known about the conditions it needs to survive. Bonytail can live up to 50 years, and biologists believe it likely needs floodplain wetland habitat to reproduce.
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Photo credit: U.S. Fish and Wildlife Service
Colorado pikeminnow
(Ptychochelius lucius)#
Endangered#
The Colorado pikeminnow will challenge any preconceptions you may have about minnows. Historically growing up to 6 feet long and weighing 80 pounds, pikeminnow is the largest minnow in North America. It can travel up to 200 miles in search of shallow gravel bars to spawn. Young fish require calm backwater nursery habitat created by spring floods.
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Photo credit: Joe Ferreira, U.S. Fish and Wildlife Service
Humpback chub
(Gila cypha)#
Threatened#
The humpback chub’s unique body shape helps it feel right at home in the river’s swift currents, allowing it to stay upright even in whitewater. This fish can live up to 30 years. Young humpback chub depend on sheltered areas near the shoreline, while adults can be found in deep pools near swift moving water.
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Photo credit: U.S. Fish and Wildlife Service
Razorback sucker
(Xyrauchen texanus)#
Endangered#
The fierce new mascot for the Grand Junction baseball team, the razorback sucker, can live up to 40 years. Razorback spawn on cobbles in shallow water while young fish seek the safety of warm backwater and floodplain wetland habitat. Adults are found in deep eddies and backwaters.
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Photo credit: Sam Stukel, U.S. Fish and Wildlife Service
Before dams, diversions, and climate change, runoff from melting snowpack sent a large pulse of water down the Colorado River each spring. This peak flow left behind gravel bars for fish to lay eggs, overtopped riverbanks, and created calm backwater and wetland nursery habitat for young fish.
We have a very different river today.
From Wild Waters to a Regulated River#
The Colorado River is one of the most regulated rivers in the world. Its network of dams and pipelines deliver water to 35 million people and provide hydropower to households across the West. A long list of laws and rules govern every reservoir release and water diversion.
The river is shrinking thanks to climate change and unsustainable water demands. Flows have declined by roughly 20%, and the West just experienced its warmest winter on record. Following one of the worst snowpacks on record, the U.S. Bureau of Reclamation is predicting that flows into Lake Powell — one of the river’s major reservoirs — will be just 36% of average between April and July. The reservoir is less than one-quarter full.
The river’s dams and diversions cannot function properly without enough water. At Lake Powell, low water levels threaten to cut off hydropower, damage the tubes used to move water downstream, and severely limit flows through the Grand Canyon.
Lake Powell Key Reservoir Elevations
3,490 feet (minimum power pool): The absolute minimum reservoir elevation needed to turn the dam’s penstocks and produce hydropower. Dropping below power pool not only affects power production across the West, but it also forces dam operators to rely solely on the dam’s outlet works — a series of four large tubes — to send water downstream. The outlet works were never designed for long-term use and have already shown signs of damage when used in recent years.
3,370 feet (deadpool): The point at which the reservoir has fallen so low that water doesn’t reach the outlet works to move water downstream. This severely limits water releases to serve downstream communities and maintain flows in the Grand Canyon.
Making the Most of a Bad Situation#
Fortunately, Reclamation has a way to protect critical elevation levels in Lake Powell in the short term.
In 2019, the Upper and Lower Basin Drought Contingency Plans were developed to address the growing water shortage on the Colorado River. The Upper Basin plan included the Drought Response Operations Agreement (DROA). This agreement created a process for transferring water from reservoirs upstream down to Lake Powell to keep it from falling below minimum power pool. This transfer is like a loan — reservoirs that release water for DROA would be given an opportunity to refill in the years after the release.
In early 2022, the West was feeling the effects of a terribly dry winter. Fish and wildlife were struggling, and Lake Powell was approaching critically low levels. The Endangered Fish Recovery Program — a team made up of government agencies, Tribes, water users, and conservation groups like WRA — was looking for ways to help fish survive the dry summer ahead.
Meanwhile, Reclamation and the states were planning to release an additional 500,000 acre-feet of water from Flaming Gorge reservoir on the border of Utah and Wyoming to protect infrastructure at Lake Powell. The water was going to flow through important fish habitat in the Green River before meeting up with the Colorado River in Canyonlands National Park — and that gave the Recovery Program partners an idea.
The Recovery Program had previously conducted “flow experiments” where water was sent down the river timed to benefit native fish in several ways, including by maintaining healthy river flows and limiting the spread of invasive fish. DROA was a unique opportunity to build on these efforts.
If timed correctly, the Flaming Gorge release could mimic the natural spring peak flows that native fish have counted on for millions of years. The Recovery Program wrote up a request for timing DROA releases. Included in that request were reservoir releases to send water to wetlands to support larval fish and create undesirable conditions for invasive fish. The same release would also benefit recreation on the Green River and boost hydropower production to help keep the lights on in the West. WRA voiced our strong support.
The plan was accepted by Reclamation and the Upper Basin states. That year several well-timed releases of water were sent downstream, breathing new life into the parched Green and Colorado rivers. A few months later, biologists donned their waders and went to check on the fish. What they found was staggering.
The team collected a record-breaking 4,577 juvenile razorback sucker fish from four wetlands managed as nursery habitat — habitat that would not have existed without the Flaming Gorge DROA release. For comparison, biologists had only collected 4,617 juveniles across all the wetlands between 2012-2021.
We Have Another Opportunity to Help the Fish#
Spring is upon us. Across the Colorado River Basin, the cottonwoods are starting to leaf out, cacti are getting ready to bloom, and bears are emerging from their slumber. It’s nearly time for the river’s fish to seek out spawning habitat, and soon juvenile fish will be looking for refuge in the quiet wetlands and backwaters created by spring floods. But after the warmest winter on record, there will be no significant spring floods, expansive wetlands, or stretches of backwater habitat without our help.
The Bureau of Reclamation is again considering making increased releases from Flaming Gorge reservoir to help protect Lake Powell. If strategically timed, that water could once again mimic the river’s natural spring flows, rejuvenate habitat, and give fish a chance. WRA will be working closely with decision makers and agency staff in the coming weeks to see this through.
Looking to the Future#
The 2019 DROA expires this fall along with the broader management guidelines for the Colorado River. It’s time to think about what comes next.
DROA is an important stopgap measure to protect fish and maintain critical reservoir levels in dry years, but it shouldn’t be our only tool.
Drought operations are only implemented in emergency situations, like using your savings account to cover an unexpected expense. It takes time to build our savings back up and so we cannot rely on this form of drought operations to maintain healthy river flows every year.
In addition to having a plan for emergencies, we also need to rebalance the budget to prepare for a future with less water. This means adopting proactive management guidelines that apply across the whole Colorado River Basin to save water, maintain consistent healthy river flows, and stabilize reservoirs.
The bonytail, pikeminnow, humpback chub, and razorback sucker have been an integral part of the Colorado River for millions of years. Their continued survival depends on how well we manage the river over the long term.
