The Other Border Dispute Is Over an 80-Year-Old Water Treaty

This story was reported with a grant from The Water Desk at the University of Colorado Boulder.

EL PASO—Maria-Elena Giner faced a room full of farmers, irrigation managers and residents in the Rio Grande Valley of Texas on April 2. 

The local agricultural community was reeling. Reservoirs on the Rio Grande were near record lows and the state had already warned that water cutbacks would be necessary. The last sugar mill in the region closed in February, citing the lack of water.

But Mexico still wasn’t sending water to the U.S. from its Rio Grande tributaries, as a 1944 treaty requires the country to do in five-year intervals. 

“We haven’t gotten any rains or significant inflows,” said Giner, the commissioner of the International Boundary and Water Commission. “It’s not looking good.” 

The IBWC, based in El Paso, implements the boundary and water treaties between the two countries. Giner’s team had spent 2023 working to reach an agreement with Mexico to ensure more reliable water deliveries on the Rio Grande. In December, she was confident the U.S. and Mexico would sign a new agreement, known as a minute. But at the final hour Mexico declined to sign. 

The impasse left farmers and communities in the Rio Grande Valley facing down another hot summer with limited water supplies. The state of Texas and members of Congress joined the supplications to Mexico: Start sending the water you owe. But with the political opposition in Mexico calling for the water treaty to be renegotiated—and presidential elections approaching in June—Mexican officials waited.

Immigration, trade and drug trafficking dominate much of the U.S. diplomatic agenda with Mexico. But in recent months water has become a more urgent topic, rising to the “upper echelons of the Department of State,” in Giner’s words. The 1944 treaty between the U.S. and Mexico governs water distribution on both the Rio Grande and Colorado River. Drought, climate change and politics are increasing tensions over treaty compliance. 

As of May 20, United States ownership of water at the Falcon and Amistad Reservoirs was at 20.1 percent of normal conservation capacity. South Texas farmers and municipalities are figuring out how to make do with less this summer.

Texas Republican Senators John Cornyn and Ted Cruz and members of both parties in the House are pushing for the State Department to withhold funds for Mexico. 

Giner, who herself grew up between the two countries in Ciudad Juárez and El Paso, remains convinced the neighboring nations can work out their differences over an 80-year-old treaty to manage shared rivers. 

“[This minute is] the tool that we have at the IBWC,” Giner said during the April meeting. “Mexico is a sovereign country. And our tool is influence.”

Rio Grande Valley Farmers Fear More Losses

The Rio Grande starts its 1,900-mile journey to the Gulf of Mexico high in the mountains of southwestern Colorado. But the water that flows through the Texas Rio Grande Valley mostly originates in tributaries in Mexico. The most important is the Rio Conchos that flows from the Sierra Tarahumara through the agricultural heart of Chihuahua before joining the Rio Grande at Presidio, Texas.

The 1944 water treaty commits the U.S. to send Mexico 1.5 million acre-feet of water from the Colorado River each year. On the Rio Grande, Mexico is expected to send an average of 350,000 acre-feet of water from the Mexican tributaries each year over a five-year cycle for a total of 1.75 million acre-feet. This water flows to the Falcon and Amistad Reservoirs, which store water for the farms and communities of the Rio Grande Valley and the downstream Mexican states of Tamaulipas and Nuevo León. 

The last five-year cycle ended in conflict in 2020, with farmers in Chihuahua protesting water deliveries to the U.S. In a last-minute deal, known as minute 325, Mexico agreed to transfer water stored at the international reservoirs to the U.S. to end the cycle without a deficit.

The current cycle ends on October 25, 2025. Well into the fourth year, Mexico has sent less than 400,000 acre feet of water. At this rate it is unlikely that Mexico can meet its obligations.The main reservoirs on the Rio Conchos are at low levels, with La Boquilla at 28 percent capacity and Francisco Madero at 25.8 percent, as of May 16. The entire state of Chihuahua is currently in a drought.

With irregular water deliveries hampering agricultural production, the last sugar mill in Texas, the Rio Grande Valley Sugar Growers, closed for good in February. 

“I just don’t see a means by which sufficient water could be delivered right now in time to save the agricultural production for this year,” said Carlos Rubinstein, a former Texas Commission on Environmental Quality Rio Grande watermaster and consultant. “So the water is going to have to come from Mother Nature this year, which is a bad spot to be in.”

Towns and cities in the Rio Grande Valley that rely on the river for their water could also face shortages this year. Municipalities may be forced to buy additional water or speed up plans to develop alternative water supplies, like desalination. 

The Delta Lake Irrigation District diverts water to municipalities including Raymondville and Lyford. Water for these communities is conveyed through irrigation canals; if there is no irrigation water the municipal water can’t move through the canals.

“The water is going to have to come from Mother Nature this year, which is a bad spot to be in.”

“We’re at a point where within the next 60 days if we don’t get substantial rainfall or Mexico releases some water… I don’t know what my municipalities that I deliver water to are going to have to do,” said general manager Troy Allen in early May.

“We’ve already lost the sugar industry in the Rio Grande Valley,” Allen said. He worries the citrus industry will be next. “That’s my big fear.”

Negotiations Advance Then Falter in 2023

State and federal officials tried to avoid this. 

Minute 325, signed by the U.S. and Mexico in October 2020, set the goal of signing a new minute by December 2023 to increase “reliability and predictability” in Rio Grande water deliveries.

The Rio Grande Minute Working Group formed in 2022 with representatives from IBWC, the TCEQ, the Department of State, Mexico’s IBWC, known as CILA, and Mexico’s National Water Commission, known as CONAGUA.

In Mexico, water is federal property. But once that same water is delivered to the U.S. in the international reservoirs, it falls under the purview of the state of Texas. TCEQ’s Rio Grande Watermaster then manages deliveries to irrigation districts and other users. While IBWC handles direct negotiations with Mexico, the agency must work closely with TCEQ. 

Giner wrote to TCEQ Commissioner Bobby Janecka, a member of the working group, in January 2023. She wrote in an email, provided by TCEQ in a records request, that she looked forward to “achieving a minute signing that will lead to predictability and reliability in the Rio Grande.”

TCEQ has urged IWBC to do more, and political tensions on the border have bled into the water dispute. “IBWC must hold Mexico accountable,” wrote the director of the agency’s Office of Water at the end of January 2023.

In late June 2023, IBWC took issue when Texas Governor Gregg Abbott ordered floating buoys designed to stop migrants to be installed in the Rio Grande near Eagle Pass. IBWC denounced the move, saying they were not consulted and the buoys could violate treaty agreements. Tensions with Mexico flared; Mexico’s top diplomat lodged a complaint with the U.S. government, warning the buoys violated the 1944 treaty and were possibly in Mexican territory. The U.S. Department of Justice later sued Texas. (That case is now in the Fifth Circuit Court of Appeals. 

On July 18, 2023 IBWC foreign affairs officer Sally Spener notified TCEQ that Mexican officials had postponed a meeting because of the incident, according to emails obtained by Inside Climate News. 

“We were able to continue our negotiations through all of that last year,” Spener said in a May 2024 interview, referring to the buoy controversy. “But it was a distraction.”

Spener said by the second half of 2023, the working group put “concepts on paper” and drafted a minute laying out what the two countries agreed on.

On December 5, the IBWC presented details of the draft minute to stakeholders in the Rio Grande Valley. Irrigation districts and farmers in the valley don’t always agree with the federal government’s approach to working with Mexico, so their buy-in was important. Commissioner Giner explained how key points in the minute would resolve long-standing disagreements about the treaty.

Some irrigation districts and politicians in Chihuahua argue that Mexico should only allocate “wild water,” or water that overflows the country’s domestic dams, to fulfill the treaty. The draft minute would reinforce the importance of Mexico releasing water from its domestic reservoirs, settling that debate. 

Mexico’s San Juan and Alamo Rivers have previously been used to supplement the five tributaries named in the treaty. The draft minute affirmed that, when the U.S. agrees, Mexico could allot water from these rivers to meet its obligations.

The draft also included a new “projects” working group that would focus on increasing water conservation in the drought-impacted watershed. A separate “environment” working group would focus on the Big Bend and increasing water flow in an area that runs dry much of the year. 

“There was some of it that we didn’t agree with, but it was a start,” said Troy Allen of the Delta Lake Irrigation District of the draft minute. “[Commissioner Giner] is very transparent and I think she is really trying her best to help us out.”

IBWC was poised to sign the minute in December. Suddenly Mexican federal officials backtracked, saying they needed to “undertake additional domestic consultations,” according to Spener. Until those consultations were complete, Mexico wouldn’t sign the minute.

Not everyone in Mexico wanted the new agreement. The heart of that opposition lies in Chihuahua.

Mexican Opposition Politicians Protest Water Deliveries

Mexican presidential candidate Xóchitl Gálvez took the stage in Camargo, Chihuahua, on April 14. She spoke just a few miles from La Boquilla, where Mexican farmers protested water deliveries to the United States in 2020.

Those same farmers were out in force for Gálvez, who is backed by Mexico’s three main opposition parties, the PAN, PRI and PRD. Her opponent from the MORENA party, Claudia Sheinbaum, is the hand-picked successor to incumbent president Andrés Manuel López Obrador. 

In 2020, López Obrador sent the National Guard to the La Boquilla reservoir in anticipation of opening the floodgates to send water north. Protesters pushed out the National Guard and a protester was killed in the confrontations. 

Gálvez opened her speech this spring discussing water. “We are in the worst drought in many years,” she said, before launching into criticisms of MORENA’s agricultural policies.

“The treaty payment to the United States in 2025 has to be renegotiated,” she said to cheers. “I promise I will defend the water of Chihuahua.”

Chihuahua governor María Eugenia Campos Galván also opposes water deliveries. Representing the PAN, Campos Galván is one of the few opposition governors in Mexico. For her, defending the water of Chihuahua means challenging the federal officials who send water to the United States.

Chihuahua Congressman Salvador Alcántar, also of the PAN, was instrumental in the 2020 protests. He is steadfast that the water stored at the reservoirs along the Rio Conchos should not be sent to the United States.

“We are in an extreme drought in Mexico. Right now it will be difficult to comply with the commitments in the treaty,” he said in an interview in Spanish. “No one is obligated to give what they don’t have.”

Texas and IBWC officials acknowledge that Mexico’s upcoming presidential election on June 2 cast a shadow over the minute negotiations. Sheinbaum is heavily favored to win. But the federal government is not expected to take action on the treaty or water deliveries in the interim.

“We continue to push for the minute,” said IBWC’s Spener. “And even without the minute [Mexico] can make water deliveries.”

CONAGUA, which manages water allocations on the Rio Conchos, did not respond to questions from Inside Climate News. 

Bad Weather and Bad Politics

Mexico alone doesn’t shoulder the blame for water shortages this year. A prolonged drought and climate change are pummeling the Rio Grande watershed and Mexican tributaries alike. Extreme heat is already taking a toll on agriculture in the Rio Grande Valley. These trends are only expected to continue.

Temperatures throughout the Rio Grande basin are projected to increase by four to 10 degrees Fahrenheit this century, according to the Bureau of Reclamation. Higher temperatures decrease snow accumulation and snow melt. More water evaporates from reservoirs as temperatures warm. 

Drought and rising temperatures are also impacting the Conchos basin in Mexico. Annual runoff in the Conchos basin could decline by up to 25 percent by 2050 because of changes in precipitation and higher temperatures, according to the 2015 Mexico Water Vulnerability Atlas. A study in the Journal of Climate this year projected that Chihuahua is likely to “experience strong drying during the spring and summer months” this century. 

Texas politicians are pressuring the Biden administration to take more decisive action to help the state’s farmers. On May 10, Sens. John Cornyn and Ted Cruz, along with eight representatives, including Republicans Monica De La Cruz and Tony Gonzales and Democrats Vicente Gonzalez and Henry Cuellar, sent a letter urging the both the House and Senate Appropriations Subcommittees on State and Foreign Operations to withhold designated funds from Mexico until the country “meets its obligations to resolve the ongoing water dispute.” 

López Obrador spoke to the treaty on May 15 during his daily press conference. He said Mexico does not have a date to make a decision. “We support this compact,” he said. “We agree it shouldn’t be modified and we have a very good relationship [with the United States]. But as the weather gets hot and there are elections coming up, all these issues come to light.”

The Department of State referred questions about the treaty negotiations to IBWC. 

Spener of the IBWC said they continue to encourage Mexico to deliver water. The minute working group held its most recent meeting in April in El Paso. 

TCEQ Commissioner Bobby Janecka wrote to Commissioner Giner on April 26, concerned that Mexico continued to allocate water to its irrigation districts without planning how to send water to Texas. He also opposed Mexico arguing that extraordinary drought prevented the country from complying with the treaty. “We are deeply concerned about these claims,” he wrote.

Irrigation districts in the Rio Grande Valley worry about trade-offs when the U.S. agrees to alternative measures—beyond the five tributaries named in the treaty—for Mexico to deliver the water it owes. Anthony Stambaugh, general manager of the Hidalgo County Irrigation District No. 2., said Mexico “needs to be caught up first,” before the U.S. offers more concessions.

When the treaty clock runs out on October 25, 2025, both the U.S. and Mexico will have entered new presidential administrations. The incoming U.S. president will also appoint the IBWC commissioner. The tone of binational negotiations could change dramatically.

Mexicans go to the polls on June 2. Water issues, from Chihuahua to Mexico City, have taken on greater importance during the campaign. Water shortages are spreading to more neighborhoods in Mexico City as supplies dip. Frontrunner Sheinbaum is largely expected to continue her predecessor’s policies if elected. She has committed to making water management a priority and would consider a revision of the National Water Law. Meanwhile, her opponent Gálvez has said, if elected, she would modernize agriculture to make more efficient use of water.

Six months later, the United States will hold its presidential election. Water and the 1944 treaty are hardly top campaign issues north of the border. But, if elected, Republican candidate Donald Trump would likely take a more confrontational approach in his dealings with Mexico. Meanwhile, the Biden administration has invested heavily in water conservation in Western states, including in the Colorado River Basin and the Rio Grande. These investments, through the Inflation Reduction Act and the Bipartisan Infrastructure Law, would likely continue if Biden is re-elected.

In the Rio Grande Valley, the immediate concern is how to get through a dry, hot summer with less water to go around. As water supplies dwindle—and the political divide widens—the immediate needs to secure water will take precedent.

Carlos Rubinstein, the former TCEQ watermaster, said resolving the root issues of water supplies on the Rio Grande requires continuous work, not just during the bad years.

“It’s bad weather and it’s bad politics,” he said. “So that’s a really tough place to be.”

This story was produced by Inside Climate News, in partnership with The Water Desk, an independent initiative of the University of Colorado Boulder’s Center for Environmental Journalism.