As stakeholders across the U.S. West prepare to rewrite the rules on Colorado River conservation, experts are urging them to consider Mexico’s needs up front.
The 1,450-mile waterway, which stretches from the Rocky Mountains to the Sonoran Desert, is considered the lifeblood for about 40 million people in both countries.
Prioritizing cross-border investments could help ensure stability in a basin that for years has been facing megadrought conditions both up and downstream, according to policy advisors in the region.
“There’s wisdom in seeing that one watershed is a reality in the Colorado River,” said Carlos de la Parra, a water management and environmental policy advisor on the U.S.-Mexico border.
“You tally all of the costs, and you divide them equitably,” de la Parra told The Hill.
The Biden administration last month officially launched the process to rewrite the Colorado River’s Interim Guidelines for Lower Basin Shortages — set to expire at the end of 2026 — which define how much water users need to conserve and when they must do so.
Although the result of these talks could have a significant effect on Mexico, which is entitled to about 9 percent of the Colorado River’s total flow, they technically involve only U.S. federal, state and tribal entities.
But just as those guidelines run their course, so too will a separate binational agreement that spells out precisely how the U.S. and Mexico jointly manage the river — meaning that international renegotiations will be occurring in parallel with the domestic conversations.
“Every player, here in the basin, has leverage,” said Yamilett Carrillo, senior manager of the San Diego Foundation’s Binational Resilience Initiative. “Everybody shares the same risk. If we don’t do our part, if we don’t contribute to solutions, then everybody will suffer.”
The Colorado River spends most of its time in the U.S. before entering Mexico and tapering off just south of the international border, straddling the states of Sonora and Baja California.
A 1922 compact allocated 7.5 million acre-feet of water annually to each of two basins in the U.S., while the Mexican Water Treaty of 1944 then granted an additional 1.5 million acre-feet to Mexico. For reference, a typical suburban U.S. household uses about an acre-foot of water each year.
Historically, the Colorado River flowed to Mexico’s Gulf of California. Today, however, the river flow usually dwindles much closer to the border, due to withdrawals and diversions upstream.
The mechanism that is instead responsible for fulfilling Mexico’s annual allocation is a border area gateway called the Morelos Dam, which is jointly administered by the U.S. and Mexico through the International Boundary and Water Commission (IBWC, or CILA in Mexico). Most of the water that passes through the dam is rerouted to irrigate Mexicali Valley agriculture.
“The U.S. controls the faucet, as it were,” Jennifer Pitt, Colorado River program director for the Audubon Society, told The Hill.
“Mexico’s leaders have decided that it’s better to have a known agreement about what quantities of water they’ll be receiving under different conditions than to not have an agreement and be left with the decision in the hands of people in the U.S.,” Pitt said.
Shifting the conversation on conservation
The U.S. and Mexico have authorized a long list of IBWC decisions — known as “Minutes” — on shared water resources since 1944. But two of the most groundbreaking resolutions regarding the Colorado River occurred in recent years: Minute 319 in 2012 and Minute 323 in 2017.
These two agreements became a testament to the value of partnership between the two countries — and provided evidence that such bilateral conversations could benefit water users across the entire basin.
Minute 319 extended measures that had allowed Mexico to delay receipt of its Colorado River allotment, as the country repaired infrastructure damaged during the 2010 El Mayor-Cucapah earthquake. The U.S. agreed to store the deferred shipment in the Lake Mead reservoir, while also establishing cuts that Mexico could incur during shortage conditions.
The U.S. providing Mexico with this needed assistance in storing water — at no charge — demonstrated that the two countries “are in this together,” said Carrillo, who served as a scientific advisor in previous negotiations.
As part of Minute 319, the U.S. also agreed to release about 105,000 acre-feet of water into the Colorado River Delta in 2014, for a two-month period known as the “pulse flow,” which allowed the waterway to revive wetlands and briefly reach the Gulf of California.
Minute 323, meanwhile, maintained Mexico’s ability to store water in Lake Mead, while also requiring the U.S. to invest $31.5 million in Mexican water efficiency projects and creating a work group that explored the idea of establishing a binational desalination plant in a region.
Another critical component of Minute 323 was Mexico’s willingness to cut back on consumption during times of water shortage. That agreement, however, would only take effect after U.S. basin states implemented their own reduction protocols.
This demand from Mexico marked a noteworthy shift in the bilateral relationship, in which the U.S. would typically make assumptions about the other country’s conservation abilities rather than including its delegates in a collaborative process, according to Pitt.
Like both Minute 323 and the 2007 Interim Guidelines for Lower Basin Shortages, the state-level reduction protocols are also set to expire in 2026 — now poised to be a pivotal year for Western water.
The agreements together ended up triggering temporary conservation measures in both Mexico and the U.S. Lower Basin States — California, Arizona and Nevada — in the summers of 2021 and 2022, amid severe drought conditions.
Cross-border compensation for cutbacks
While experts expressed uncertainty as to what exactly will happen as delegates head to the post-2026 negotiating table, they expressed confidence that the two countries understand the mutual benefit of basin-wide conservation.
“There has been now a pretty strong history of stakeholder participation that’s developed since the 2007 guidelines,” Peter Culp, a Phoenix-based attorney who specializes in Colorado River law, told The Hill.
Now Mexican officials have an expectation that they will “be a part of discussions from the get-go,” de la Parra agreed, noting that private hallway conversations are probably already taking place in both countries.
Beyond this rebalance of negotiating power, another difference between 2007 and 2026 is that in the earlier year the parties thought they were just “solving for a drought,” according to Culp, who has participated in stakeholder efforts to develop and support previous international agreements in this basin.
“Twenty years later, we’re definitely solving for something that’s much more than a drought — it’s climate change,” Culp said.
“What is it going to take to put the basin on a more sustainable footing in the face of continued aridification, where things may continue to worsen over time?” he asked.
For scholars and scientists across the region, the answer to this question — as far as Mexico is concerned — revolves around agricultural conservation, and the funding necessary to revamp a sector that makes very little profit.
Farmers irrigating their crops with Colorado River water, mostly in the Mexicali Valley, have thus far had little incentive or financial ability to make significant upgrades, according to de la Parra, the expert on water issues at the U.S.-Mexico border.
“The bulk of the weight right now is being carried by an agricultural community that hasn’t developed a resilience for water shortages — it didn’t need to over the course of 75 years. So why would it develop that ability?” de la Parra asked.
Lasting measures to help withstand drought, he explained, would involve replacing infrastructure, leveling land, improving efficiency and doing “everything related to modernizing irrigation districts that is lagging behind” — actions that would cost more than Mexico can afford.
“Mexico is pretty much aching for additional funding. It doesn’t have the financial resources that are exhibited in the Inflation Reduction Act,” de la Parra said, referring to the massive climate-related provisions in the Biden administration’s 2022 spending bill.
Any substantial investment in modernizing Mexicali Valley agriculture would need to “be premised on a compensation mechanism,” according to a consultant who works closely with various Colorado River stakeholders, but who requested to remain anonymous due to the sensitive nature of ongoing talks.
Echoing de la Parra’s sentiments, the consultant said they believed the best strategy would be “to make investments in agricultural land directly.”
“The reality of the situation is that there’s just a significant resource disparity,” the consultant added. “We’re kind of all in this together. And conservation of Mexico benefits system stability in the United States, just as much as it does in Mexico.”
With that in mind, the experts surfaced the idea that in return for Mexico’s agreement to conserve additional water, the U.S. could potentially invest in revamping Mexicali agricultural infrastructure and introducing farmers to higher-value, less water intensive crops.
“If the U.S. wants to have a resilient outcome, it is in the U.S.’s interest to help with that transition in the Mexicali Valley — help finance the transition to agricultural operations that can continue to produce value with less water,” Pitt said.
That shift is unlikely to occur through private financing alone, as the “economics are not going to support an independent transition to what we need agriculture to be in a climate-challenged basin,” added Culp.
“That leads you to the inevitable conclusion that we’ve got to drive public investment to it,” he said.
A river that flows ‘both ways’
Even if the U.S. were to funnel funds into overhauling regional irrigation infrastructure, optimizing the flow of water to where it is needed often requires both flexibility and creativity among Colorado River users.
De la Parra offered one hypothetical scenario, in which Arizona water authorities might decide “to line canals in the Mexicali Valley in exchange for a given volume of water.”
This type of swap would hardly be reinventing the wheel, as similar such transactions occurred during both Minutes 319 and 323, de la Parra noted.
Another possibility could involve building a binational desalination facility — an option evaluated in the study that followed Minute 323. The report explored the feasibility of several locations, including along Mexico’s Pacific Ocean Coast or at the Sea of Cortez in the Gulf of California.
“The former commissioner of Mexico would say that the beauty of the Colorado River is that it can actually flow both ways,” de la Parra said.
He expressed confidence that San Diego or Los Angeles would be happy to pay for their share of a desalination plant, in exchange for some of Mexico’s Colorado River allocation. California and Baja California may have separate regulatory systems, but sharing costs like land use, environmental impact and energy would benefit the entire region, according to de la Parra.
While Pitt expressed skepticism about the overall impact of a desalination facility on the Colorado River basin, she acknowledged that “it would really change some of the power dynamic between the US and Mexico in terms of sort of control over supplies.”
But she warned that such a project would by no means be “a panacea,” as it wouldn’t close the supply-demand gap in the region. Such an energy-intensive facility would also require a new power source, as well as the requisite permitting processes, Pitt noted.
Beyond strict water supply and augmentation considerations, Pitt said she will be urging delegates to consider certain environmental provisions in the bilateral negotiations. Some such issues could include certain ecological restoration projects or increased focus on a salinity problem that sometimes plagues the water crossing from the U.S. into Mexico.
Carrillo, meanwhile, said she believes that considering basin-wide conservation strategies, negotiators must also account for the Tijuana River watershed, which for all intents and purposes has become a terminus for Colorado River flow.
While Tijuana is not technically located anywhere near the river, it receives a share of Mexico’s Colorado River allocation through an aqueduct that crosses the Mexicali Valley — and is therefore considered one of the most downstream municipalities in the basin. The city is also able to obtain Colorado River water from California in emergency situations.
“A lot of people still think that the Tijuana River is a completely separate watershed that has nothing to do with the Colorado River,” Carrillo said, describing this view as “a complete mistake.”
Citing opportunities to spur water conservation by investing in sewage treatment and associated infrastructure in Tijuana, Carrillo expressed her support for including the watershed in binational Colorado River negotiations.
While de la Parra agreed with Carrillo’s characterization of Tijuana as “maybe artificially, the endpoint of the Colorado River,” he also identified a major caveat. Tijuana, he explained, is responsible for only about 15 percent of the region’s water use, while the remaining 85 percent goes toward agriculture.
“When talking about water scarcity and water management and improving that, I would turn my eye towards the agricultural community,” he said. “And then secondly, of course, cities.”
Reshaping a bilateral narrative
Acknowledging that investments will play an important role in the next round of U.S.-Mexico talks, Culp stressed that so too will the development of a shared basin-wide narrative that highlights what the partners are doing together.
“Money can be a tool to help solve a problem, but the solution will be found in what the new story is,” Culp added.
Key to shaping that narrative, according to Carrillo, is a commitment to “share the plans, share the scenarios, share the assessments and comparisons with the general public.”
“There’s so much goodwill here,” she said, noting that many families in the Colorado River Delta region span both sides of the border.
Pitt likewise expressed enthusiasm for the renegotiation process — acknowledging how “daunting and complicated” it can feel to restart the process while also recognizing the “really solid history” that has developed over the past decade.
“The relationship between the U.S. and Mexico, on Colorado River management, to me appears wholly transformed from what it used to be,” she said. “I’m optimistic that another good agreement will be negotiated.”
Also emphasizing feelings of optimism, de la Parra called out claims that future wars will be about water as “completely untrue.”
“It doesn’t pan out in terms of data and in terms of trajectory,” he said. “There are more agreements on water than there are disputes.”