A shrinking lifeline: US and Mexico strike new Colorado River deal, cutting Mexico's share by 17% for two years

About 40 million people across the United States and Mexico depend on the Colorado River system for drinking water, municipal supply and agricultural irrigation.

The two countries have formally shared and managed the river for more than 80 years under the 1944 Water Treaty, which guarantees Mexico an annual delivery of 1.5 million acre-feet of water under normal conditions, TOI reported.

Water officials from both countries have now signed a new agreement that will see Mexico take less water from the river, a move experts are calling a rare success story in cross-border cooperation amid growing strain on the waterway.


The deal, known formally as Minute 334, was signed by the International Boundary and Water Commission (IBWC) on September 2 in El Paso, Texas, with US IBWC Commissioner Chad McIntosh and Secretary Sally Spener signing alongside Mexican counterparts Commissioner Adriana Reséndez and Secretary Manuel Morales.

The Colorado River originates in the snow-capped peaks of the Rocky Mountains and once flowed all the way to the Pacific Ocean along Mexico's coast. Since the 1960s, however, it has rarely reached the sea, drained by decades of heavy water use by cities and farms across the American Southwest.

A treaty that keeps evolving

This isn't the first time the 1944 treaty has been adjusted. The two nations have periodically renegotiated their water-sharing terms through a series of supplementary agreements known as "Minutes." The current arrangement, agreed in 2017, expires at the end of this year; the new Minute 334 will run from the start of 2027 through the end of 2028.

Under the new terms, Mexico will absorb its largest cuts yet, with its allocation reduced by 250,000 acre-feet, about 17% of its original share, roughly equivalent to more than 100,000 Olympic swimming pools' worth of water.

The agreement also allows Mexico to defer part of its delivery and store it in Lake Mead to help shore up the reservoir, though that stored water is largely inaccessible if the lake's level falls below 1,025 feet on January 1. A related clause permits further reductions if Lake Mead is projected to drop below 1,000 feet; the reservoir currently sits at roughly 1,038 feet.

Why officials are calling it a win

Jennifer Pitt, Colorado River programs director at the US-based National Audubon Society, said Mexico's willingness to take a larger cut carries wide-ranging benefits. She said she was "extremely pleased" the deal was reached on its own terms, without being entangled in "any of the other broader geopolitical issues that can be present in diplomatic relations."

The agreement, she noted, was hammered out through the IBWC, an institution founded in 1889 to manage the Rio Grande and Colorado River.

"I think that's remarkable," Pitt said. "Particularly at this moment on the Colorado River, where there are so many disagreements and so much uncertainty. The fact that the United States and Mexico are still able to reach these agreements is important and really beneficial to all water users."

Carlos de la Parra, managing partner of the Mexico-based Luken Centre for Strategies on Water and Environment, credited the "institutional design" of the binational negotiating process, which relies on in-person visits to water infrastructure on both sides of the border rather than remote diplomacy. "You don't discover this sitting behind a desk in Washington, DC, or Mexico City," he said.

"You discover it by being right at the border and by really talking across the border to your counterpart in the commission." De la Parra, who has informally advised Mexico's negotiators for about 15 years, said the Colorado River process could offer lessons for other areas of US-Mexico relations.

Restoring the delta

The agreement also sustains ongoing environmental restoration work in the Colorado River Delta, where a coalition of environmental groups has spent years using small, carefully managed volumes of water to regrow patches of vegetation in the desert, largely to support habitat for migratory birds.

Under Minute 334, an environmental work group will continue this effort with roughly $5.6 million in joint funding from both governments and non-governmental partners.

The Raise the River Coalition, whose restoration sites will not directly draw water from the new agreement, said in a statement that its own water holdings, secured over more than a decade of investment, remain sufficient to sustain the restoration sites developed with both governments since 2012. The coalition called the new deal "a responsible, forward-looking response to a drier basin, while preserving the framework for environmental cooperation."

A study published in June found the restoration work has resulted in more than 250,000 trees planted across nearly 1,400 acres of riparian habitat, with researchers noting that "a little bit of water can go a long way" in the delta.

Meanwhile, US states are still fighting it out

While the US and Mexico reached consensus relatively smoothly, American states sharing the river have struggled to agree among themselves. Years of negotiations between the states failed to produce a deal, forcing the federal government to step in with its own water-sharing plan.

In late August, the Bureau of Reclamation released a two-year operating plan requiring the lower basin states, Arizona, California and Nevada, to cut their combined use by 1.25 million acre-feet over the next two years, a plan that remains controversial and could trigger lawsuits.

Pitt said the binational deal, by contrast, gives Mexican water users a measure of stability even as the American states continue to sort out their differences. "Many water users are going to be experiencing discomfort and pain because of a reduced water supply," she said.

"But I think it provides them with the security of knowing exactly what the rules of the game are. They have the certainty of knowing what their water supply will be. They are able to plan around that."

(With inputs from TOI)