As the clock ticks toward 2026, the future of the Colorado River is once again on the negotiating table, forcing states, tribes and international partners to confront a century-old agreement under the strain of climate change, overuse and competing demands.

The Colorado River serves as a lifeline to tens of millions of people across the Southwest. Next year marks the expiration of several existing agreements regarding its use, which have been crucial to managing the river’s water supply.

The Colorado River “runs about 1,500 miles from the Rocky Mountains through the Gulf of California to the Sea of Cortez and supplies 25 to 40 million people, 30 recognized tribes and is important for hydropower and farmland,” Andrea Gerlak, director of the Udall Center for Public Policy, said during the University of Arizona’s 2025 Water Resources Research Center conference last month.

In 1922, seven states — Arizona, California, Colorado, New Mexico, Nevada, Utah and Wyoming — created a compact that divided the Colorado River’s water supply and split the states into two different divisions. These include the upper basin, made up of Colorado, New Mexico, Utah and Wyoming, and the lower basin, which includes Arizona, California and Nevada.

Gerlak said the compact allocated around 14.5 million acre-feet between the seven states, and later, 1.5 million acre-feet to Mexico.

“An acre-foot is equivalent to a football field in size and one foot deep,” she said. “One acre-foot of water is enough to serve roughly two to three U.S. households a year.”

When the Colorado River Basin first started to see signs of a shortage, the seven states established the 2007 Interim Guidelines and, in 2019, added drought contingency plans. These agreements establish cuts in water allocation when the surface level of the river reaches a certain point.

The seven states collectively use about 16.5 million acre-feet of water per year, Gerlak said. But the average flow of the river is about 13.2 million acre-feet, leaving a 2 to 3 million acre-foot deficit.

“It’s already overallocated, and then climate change is expected to reduce the flow of the basin even further,” Gerlak said.

She urged attendees to think about water use the way one would teach a teenager to manage their bank account.

“We need more inputs than outputs,” she said.

The river gets most of its water from melting snowpack, but it’s seen below-average runoff in recent years.

“And then climate change is expected to reduce the flow of the basin even further,” Gerlak warned.

With the 2007 and 2019 agreements expiring next year, along with the 1944 United States-Mexico Water Treaty, negotiations have begun between state officials, tribal leaders, the federal government and Mexico.

One of the panelists likened the negotiation sessions to marriage counseling, with the involved parties all fighting to be understood.

"There can never be effective consultation unless you understand the history and background of the tribe or tribal nation you want to consult with,” said Judge Amelia Flores, chairwoman for the Colorado River Indian Tribes. “Effective consultation means understanding who we are and about our values.”

Flores has been involved in multiple consultations and says the way to work with tribal communities is all about building relationships. She said tribal consultation is a process and must be early, timely and respectful.

“Don’t come to us under the guise of seeking a consultation when it’s too late for any meaningful ability to adjust based on our input,” she cautioned.

Binational collaboration is also a key factor for negotiations, according to the Sonoran Institute’s Francisco Zamora. The institute is a nongovernmental organization that works with environmental organizations from Mexico and the United States to maintain natural resources.

“We have technology, we have community communicators and restoration specialists,” said Zamora, senior director of programs for the institute. “More recently, we have a new strategy on land protection.”

Zamora said there are two pillars that help organizations’ success: a binational agreement and funding.

Recognizing the challenges and that such collaborations are a necessity, Arizona Gov. Katie Hobbs told attendees that her administration is working to improve partnerships and create a better, more sustainable future.

“No matter what happens, we must find ways to help local communities manage their water supplies,” she said.

Arilynn Hyatt is a journalism major at the University of Arizona and Tucson Spotlight intern. Contact her at [email protected].

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