Central Arizona will bear brunt of planned Colorado River cuts

Arizona officials are awaiting final word from the federal government on an agreement that would reduce the state’s allocation of Colorado River water by 760,000-acre feet for two years.

The proposed reduction would primarily affect Central Arizona Project water users, and while seemingly daunting, many Valley cities and towns have been preparing for decades for just such an event.

“In a non-shortage year, CAP will convey roughly 1.5 million acre-feet, and a 760,000 acre-foot cut is around half of the water that would be conveyed in the CAP. It’s significant, but the good news is that we haven’t built out demand for all of the water in the CAP. So that cut doesn’t necessarily translate into a cut for every city in the way that you might imagine,” said Sarah Porter, director of the Kyl Center for Water Policy. “They’ve all been working on being prepared for this for a long time.”

The Kyl Center for Water Policy is part of the Morrison Institute for Public Policy at Arizona State University. An acre-foot is enough water to cover 1 acre in 1 foot of water, or about 326,000 gallons.

It was anticipated that the Bureau of Reclamation would issue a two-year plan of operations this week that would cement the details. But Porter said that now seems unlikely and the feds will probably only release a final environmental impact statement at this time.

“It’s going to say what the feds believe they have the authority to do over the next 10 years and it’s going to be designed to maximize their authority to respond to conditions on the river,” Porter said.

The proposed agreement first outlined in May would also reduce the river water allocation to California by 440,000-acre feet and Nevada by 84,000-acre feet. In addition, it would call on all three states to voluntarily conserve a total of 300,000-acre feet of river water.

“The expectation is most of that voluntary conservation will come from Arizona water users,” Porter said.

The reduction would affect Valley municipalities that send their Colorado River water allotments to surface-water treatment plants for treatment and distribution to varying degrees.

Phoenix, Mesa, Scottdale, Goodyear, Glendale, Gilbert and Avondale are the largest cities in the Valley that convey the river water to treatment plants. Smaller municipalities such as Cave Creek, Carefree and Apache Junction, as well as water provider EPCOR in Fountain Hills and the West Valley, also treat Colorado River water.

“The Federal action is late, inadequate and imbalanced,” said Cave Creek Mayor Robert Morris.  "Putting Americans’ water at risk could have been avoided with earlier and more innovative Federal action. Water issues in the West need new ideas to break the logjam, which our state’s water leaders have been attempting for several years with others around the negotiating table. 

"This Federal action guarantees years of litigation, uncertainty, economic loss, and interstate conflict," said Morris. 

Porter said such cities and towns will likely weather the proposed Colorado River water reduction, but they need to keep searching for new water sources if drought conditions worsen.

“Those are the cities that are at risk of a disruption if there are very deep shortages of Colorado River water,” Porter said. “But the disruption for them is that the infrastructure they’ve been relying on for years and years to take Colorado River water and treat it and send it out to taps, that infrastructure won’t have that stock of Colorado River water. So, they are at different stages of being ready to turn to alternative supplies in the case of very deep shortages.”

The specter of a depleting Colorado River is not new, and many of the cities and towns that send river water to treatment plants have put plans in place to address future cuts.

“We have a little bit of concern about Scottsdale, because Scottsdale has a much higher reliance on Colorado River water as a percentage of the tap water that it distributes. It’s about 70%. Of the about two-thirds of the water that Scottsdale uses for tap water comes from the Colorado River,” Porter said.

The northern parts of Scottsdale will require “more infrastructure to pump groundwater out and treat it and move it uphill,” Porter said.

“It requires locating wells that are tied in with water treatment infrastructure and delivery infrastructure,” she said. “I think Scottdale is on it and working on it. They still have work to do.”

Increasing water rates, such as the one enacted in Gilbert earlier this year, will become a feature, not a bug, of life in Central Arizona as available water supplies become more expensive.

“Part of the reason for Gilbert’s big rate increase was to make sure that the city was resilient in the face of Colorado River shortage,” Porter said. “Nobody likes a rate increase, but those rate increases are really critical because that’s how a city continues to make the investments it needs to make in order to stay water secure.”

Younger towns in the Valley, such as Queen Creek, receive little to no allotment of Colorado River water and have been mostly dependent on local groundwater.

For its part, Queen Creek has been working to diversify its water portfolio for years.

“Queen Creek has a minimal reliance on the Colorado River, accounting for approximately 10% of our water supply,” Utilities Director Marc Skocypec stated in an email.

Last year, the town moved to purchase 1.2 million acre-feet of stored water in the Harquahala Valley basin over the next 100 years in increments of 12,000 acre-feet per year for more than $244 million.

In 2025, the town also purchased 500,000 acre-feet, or 5,000 acre-feet over 110 years, of Harquahala water for $40 million.

“The town has been proactively working for years on a strategy for water self-sufficiency. Additional cuts to the Colorado River were expected, and the anticipated announcement reinforces why the town’s historic investment in water from Harquahala was so important for today and the future,” Skocypec stated.

The town, like many others in the Valley, has been ramping up its water conservation efforts. Porter said reducing outdoor water use can make a significant impact.

“If you just think about a resident of Queen Creek, if they reduce their outdoor water use then Queen Creek can do more with whatever the water it has on hand,” Porter said. “Reducing outdoor water use can make a big difference for a city, for a water provider. It won’t save the Colorado, but it will make a difference for the water provider.”

Cave Creek residents depend on Colorado River water from the Central Arizona Project (CAP) for 90% of their water supply. The newly announced Federal plan to address Colorado River shortages puts Cave Creek at long term risk.  This plan ignores the need for a rational allocation and participation by users in all 7 Basin States.  The 10-year plan will greatly impact the amount of water Arizona receives, potentially cutting off CAP’s deliveries to Phoenix and Tucson in the future. 

Though there are no specific reduction numbers for Cave Creek, the Town has been working in anticipation of cuts for 8 years, including installing digital water meters and software for residents to monitor their own water usage, limiting new construction, and hiring of expert consultants to guide residential conservation efforts. 

The town has  1.5 years of stored water, new well capability and have engaged in “water exchanges” with other municipalities. Additionally, the new Phoenix Interconnect will protect our existing water system and connect us to the Phoenix treatment and transportation system.

Reporter Jeff Wendt ccontributed to this story.

Janet Perez can be reached at jperez@iniusa.org. Please send your comments about this article to AzOpinions@iniusa.org. We are committed to publishing a wide variety of reader opinions, as long as they meet our Civility Guidelines.