kjzz.org · September 8, 2026
Colorado River cuts could force 'unprecedented' low water use for Arizona, new study finds
# Colorado River cuts could force 'unprecedented' low water use for Arizona, new study finds
KJZZ | By Alex Hager
Published September 8, 2026 at 7:39 AM MST
Alex Hager / KJZZ
Colorado River water flows through the Central Arizona Project canal in Phoenix on March 27, 2026.
A new paper from a group of independent water experts finds that proposed cuts to the Colorado River supplies for Arizona, California and Nevada would be “unprecedented.” It explains that recent water use in those states is already relatively low, and a new federal proposal for reining in demand even further has “no historical analogy.”
The Colorado River is shrinking due to climate change, drought and steady demand from the seven Western states that use its water. As the nation’s two largest reservoirs shrunk to record lows, the seven states that use it failed to agree on a new plan for cutting back on demand. That forced the federal government to step in with its own plan.
That plan allows the federal government to cut Colorado River water for Arizona, California and Nevada by about 40% each year between 2028 and 2036, with the sharpest cuts likely hitting Arizona.
Arizona leaders have pushed back on the plan. They negotiated for a two-year plan that means more modest cuts — around 20% — for 2026 and 2027, but they are worried that the deeper cuts could still kick in afterwards, delivering “draconian” consequences to the state’s people and economy.
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This new report seems to support Arizona officials’ concerns about the severity of those cuts.
The analysis is the latest publication from a regionwide group of academics and former officials who study and comment on the Colorado River. The group is colloquially referred to as the “Traveling Wilburys” of the Colorado River, a nickname which nods to a 1980s rock ’n’ roll supergroup that brought together musical megastars for a second career chapter.
Jack Schmidt, who co-authored the report, said the potential cuts represent a “really, really big number.”
The federal plan could cut up to 3 million acre-feet per year across the Lower Basin states of Arizona, California and Nevada. One acre-foot is roughly a year’s supply of water for three homes in the Phoenix area.
“To achieve those kind of cuts would be completely unprecedented in the Lower Basin,” Schmidt said. “We're not arguing that it should or shouldn't be, but we're saying — don't kid yourself, those are unprecedented numbers, and the economic impacts of implementing those kind of very large numbers, for which there's no historical analogy, would be very serious issues.”
Schmidt, a longtime researcher at Utah State University’s Center for Colorado River Studies, said cuts of this size should be spread out across other states. Under the new federal proposal, the Upper Basin states of Colorado, Utah, Wyoming and New Mexico are not forced to take mandatory water cuts.
“The fact that those magnitude cuts are without historical precedent leads me to think that there's no way you can ask the Lower Basin to make those magnitude cuts and not ask the Upper Basin to do anything,” Schmidt said.
Alex Hager / KJZZ
The Colorado River flows past Lees Ferry in Coconino County, Arizona on June 17, 2026.
To put the cuts into historical context, Schmidt and his colleagues looked at consumptive water use in each of the Lower Basin states over the past 17 years. They took the single lowest January total for water use, the single lowest February total for water use, and so on, for each month on the calendar and added them all up — creating a hypothetical “year” of extraordinarily low water use across Arizona, California and Nevada.
That theoretical year has states using less water than they have used in any real year during that period.
The maximum possible cuts under the new federal plan would force those states to use even less water in a year than the hypothetical “year” Schmidt created to exemplify extraordinary low water use.
Under the maximum possible cuts, the Lower Basin would be forced to limit its annual water use to levels not seen since 1935.
The study goes on to explain some of the places where there may be “room to cut” water use, even if Lower Basin states are dramatically forced to reduce demand.
The report focuses on the Imperial Irrigation District, a farming region in the Southern California desert that uses more Colorado River water than any other city or farm district. Imperial and a handful of nearby farm regions often boast that they provide a majority of the nation’s wintertime vegetables, and are often criticized for the amount of water they use on crops that end up as cattle feed — chiefly alfalfa.
Alex Hager / KUNC
Farmer Alex Jack stands in an alfalfa field in California's Imperial Valley on June 20, 2023.
The study details how Imperial’s highest levels of water use typically occur in the summer, when grasses like alfalfa are grown, and the region has lower water use when it is producing vegetables for human consumption, like lettuce, onions, carrots and broccoli.
The report concludes that Imperial could further limit its demand for water without significantly cutting into the production of vegetables that end up on grocery shelves and kitchen tables.
“In times of acute water shortage,” it writes, “It is likely that continued and additional water savings can be achieved by reductions in irrigation of field crops in summer, without causing shortages to garden crop irrigation in the winter.”
The study also highlights the viability of future cuts to agricultural water use in Arizona. Since 2022, the amount of Colorado River water used from the Central Arizona Project (CAP) — a long canal system that mostly supplies cities and suburbs in the Phoenix and Tucson areas — is lower than the sum of all other Colorado River users in the state.
Across Arizona, Colorado River use is down, but those reductions are not spread evenly.
In the past three years, water use from the CAP was down 40% compared to the prior decade. All other Colorado River users in the state — largely farms — brought down their consumption by only 6%.
“You're going to have to find a way in Arizona to reduce the sum of those other users,” Schmidt said. “You can't have a system where all the cuts are being taken by CAP and the other users' line just sort of stays flat.”
→ Read the full report [PDF]