PHOENIX, Arizona — The Central Arizona Project (CAP), the 336-mile canal system that provides 36% of all water in Arizona, is joining the state's litigation against the federal government over Colorado River water cuts, The Center Square reported. CAP's operator, the Central Arizona Water Conservation District (CAWCD), has filed a motion to intervene in the federal case in Nevada against the U.S. Department of the Interior. This is a new party joining an existing case: Nevada first brought the litigation in August, and Arizona — through Governor Katie Hobbs and the Arizona Department of Water Resources — announced earlier in October that it was joining it, a development Awaaz Punjab reported at the time.
Source: The Center Square via Warwick Now
The motion challenges the federal operating decisions set out in the Interior Department's August 21, 2026 Record of Decision and Operating Guidelines — the Bureau of Reclamation's proposed 10-year river plan. In its motion, CAP argues the decisions conflict with the Colorado River Compact and other laws governing the river and could allow existing violations of the compact to continue, WaterWorld reported in its account of the filing. The court in Nevada has not yet ruled on CAP's motion.
Source: WaterWorld
"That water supply could be drastically reduced — in some conditions reduced to zero — based on the agency actions challenged in this case and the outcomes of the legal challenges to those agency actions," CAP's motion to intervene says. "[Central Arizona Water Conservation District] seeks leave to intervene to protect its interest and to ensure they are considered. Those interests will be impaired without CAWCD's participation."
CAP runs 336 miles south from Lake Havasu toward Phoenix and Tucson and provides 36% of all water in Arizona, serving urban communities, tribes, agriculture and other users in central and south-central Arizona. Under the disputed plan its allotment could be cut in half as soon as next year if the Southwest drought does not subside, The Center Square reported.
The cuts CAP is fighting: Lower Basin pays, Upper Basin does not
Under the Bureau of Reclamation plan released earlier this year, the three Lower Basin states — Arizona, California and Nevada — would face river-water cuts of up to 40%, while the Upper Basin states of Colorado, New Mexico, Utah and Wyoming would not have to cut back their usage. In the two-year framework described when Arizona joined the case, Lower Basin deliveries are to fall by 1.25 million acre-feet in total, with 760,000 acre-feet coming from Arizona's allocation, 440,000 from California's and 50,000 from Nevada's, starting January 1, 2027. An acre-foot is the water needed to cover one acre of land one foot deep. Arizona's negotiators have argued such reductions could effectively dry up the Central Arizona Project canal system and many on-river communities.
CAP General Manager Brenda Burman told Phoenix NPR affiliate KJZZ that the decision to join the lawsuit stemmed from the unequal cuts being asked of the seven states that signed the 1922 Colorado River Compact. "CAP has spent years negotiating with the federal government to avoid the need for this litigation," Burman said. "Our goal has been to stay out of court, but not at the expense of defending our rights and the laws governing the Colorado River. The law should be upheld." She added: "The federal government can't ignore the obligations and watch the compact be breached without any plan to bring it back into compliance and at the same time manufacture a drought for the Lower Basin. Particularly, they can't put that burden all on CAP's shoulders."
Arizona's chief Colorado River negotiator, Tom Buschatzke, director of the Arizona Department of Water Resources, told The Center Square in an email that CAP's decision stems from protecting its long-term water interests and serving its customers. "The Central Arizona Project plays a unique role in supplying vital water supplies from the Colorado River to urban communities, tribes, agriculture and other water users in central and southcentral Arizona," Buschatzke said. "We recognize they are taking this action in the best interests of their water users." Burman has also said CAP continues negotiations with water partners in California and Nevada on an agreement intended to provide water-supply certainty through 2028, even as it litigates.
Background: a century-old compact and a river that no longer fills it
The Colorado River is divided by the 1922 Colorado River Compact among seven basin states — the Upper Basin (Colorado, New Mexico, Utah, Wyoming) and the Lower Basin (Arizona, California, Nevada). CAP's legal argument, as described in the reporting, is that the federal government cannot cut its deliveries on the basis of its lower-priority water rights while the Upper Basin is not meeting its delivery obligations to Lake Mead. Sharon Megdal, director of the University of Arizona's Water Resources Research Center, told The Center Square CAP's move was not a surprise, and framed it as preparedness under deep uncertainty: Arizona, she said, is pursuing every avenue — litigation, augmentation and more conservation — to shore up a dwindling resource. She suggested one possible settlement path would be for the four Upper Basin states to agree to cut their own allotments, easing the one-sided nature of the federal plan. The Interior Department did not immediately respond to a request for comment on CAP's filing in the accounts reviewed; when Arizona joined the case, a department spokesperson said a legal dispute would not increase the amount of water in the river.
Why this matters beyond Arizona
The same plan cuts California's allocation by 440,000 acre-feet, which puts the Imperial Valley and Southern California farm districts — where many Punjabi-American farmers and truckers work the produce corridors — inside the same fight. Water cuts of this size feed directly into farm output, food prices and freight volumes on the I-10 and I-40 corridors. For Arizona residents, the immediate stake is simpler: more than a third of the state's water moves through one canal, and its operator is now telling a federal court that, under the challenged plan, that flow could in some conditions fall to zero.
What happens next
The Nevada federal court must first decide whether to grant CAP's motion to intervene; no timeline for that decision was specified in the filing coverage. The underlying case against the Interior Department then proceeds, with the disputed reductions scheduled to begin January 1, 2027 unless a court blocks them or the basin states reach a settlement — the outcome Burman said CAP spent years trying to reach through negotiation before turning to litigation. Parallel talks among Arizona, California and Nevada partners on supply certainty through 2028 continue alongside the case.
Sources: The Center Square (Christopher Boan), 'Arizona's Central Arizona Project joins Colorado River lawsuit,' October 29, 2026; WaterWorld, 'Central Arizona Project seeks to join Colorado River operations lawsuit,' October 30, 2026; University of Arizona Water Resources Research Center summary of Arizona joining Nevada's lawsuit, October 23, 2026, for the 1.25 million acre-feet framework figures.