The history behind the New Mexico-Texas Rio Grande settlement

It’s taken 10 years for the states to reach an agreement, but it may not be the end of the water conflict.

For nearly a decade, Texas has battled New Mexico over its share of the waters of the Rio Grande. On October 25, the two states announced that they reached a long-awaited settlement in the lawsuit, Texas v. New Mexico and Colorado, No. 141 Original.

 Though the settlement details are confidential, El Paso Matters reported that it was a “carve-out decree.” That means it resolves only the dispute between Texas and New Mexico, according to Jeffrey Wechsler, special assistant to the New Mexico Attorney General, not federal claims against New Mexico.


The Rio Grande flows nearly 2,000 miles from its headwaters in Colorado’s San Juan Mountains to its mouth near the border cities of Brownsville, Texas, and Matamoros, Tamaulipas, in Mexico. Over the last century, diversions for agriculture and cities such as Albuquerque and El Paso have strained the river. It regularly dries up for a stretch along the U.S.-Mexico border, and this year ran dry in Albuquerque as well.

The Rio Grande just southwest of Creede, Colorado, soon after peak runoff from snowmelt in June 2019.
Major King

The No. 141 Original lawsuit—which went directly to the Supreme Court, because it is a conflict between states—pertains to the 1938 Rio Grande Compact, which divided the waters between Texas, New Mexico and Colorado. It requires Colorado to deliver a proportion of the river’s flow, as determined by a system of stream gauges, to New Mexico. New Mexico then must deliver part of its portion to Elephant Butte Reservoir in the southern part of the state, where it is stored for use by the local Elephant Butte Irrigation District, by the city of Las Cruces, New Mexico, and by Texas and Mexico.

Texas initiated the lawsuit in 2013, when it accused New Mexico farmers downstream of the reservoir of depleting the river’s flow with groundwater pumping, thereby preventing Texas from receiving its fair share. But the case’s origins go even further back, to conflicts between local irrigation districts in southern New Mexico and West Texas that began in the 2000s.

Rio Grande River near Algodones, New Mexico, just south of Cochiti Reservoir. Much of the bosque is dying out because the river no longer floods or has pulse flows. Site of the main diversion canal for Albuquerque.
Ted Wood

The Angostura Diversion dam sends water from the Rio Grande into irrigation canals .
Jim West

The conflict is one of a long chain of water-related lawsuits involving the two states. In 2020, the U.S. Supreme Court sided with New Mexico in a separate lawsuit over the Pecos River. And New Mexico continues to battle with Texas over a pipeline rupture in El Paso that resulted in 1.1 billion gallons of sewage flowing into the Rio Grande.

These conflicts are likely to become even more common in the near future. Like the Colorado River, the Mississippi River and others, the Rio Grande is in dire straits; Elephant Butte Reservoir is currently at just 7% of capacity. Eugene White, a Montana water official who penned a 2020 article about Texas v. New Mexico, said in an email that the case signals a shift “in the court’s willingness to address some of the novel questions posed by interstate water compacts.” The fact that the Supreme Court is taking seriously conflict over a nearly 90-year-old water agreement may open the door for other reconsiderations.

Climate change is a major factor in these new conflicts. A 2013 study drawing on simulations of the Upper Rio Grande showed that decreasing water availability would make it impossible for New Mexico to meet its obligations to the Rio Grande Compact without water cutbacks. On the table in the lawsuit, then, was the question of who had to make sacrifices.

Panoramic view of Elephant Butte Reservoir and dam in September.
Ted Wood

While Texas and New Mexico have come to an agreement over that question, the case isn’t over yet. The United States Bureau of Reclamation — which joined the lawsuit because the region’s irrigation infrastructure was constructed by the agency and because the case relates to federal treaties with Mexico — opposed the settlement because it doesn’t address the agency’s concerns, only the dispute between the states. The federal government must sign off on the agreement, however, so a hearing is scheduled for January 2023 to determine whether the settlement will go through.

The Rio Grande River in El Paso, Texas, is little more than a cement channel delivery ditch that the forms the U.S.-Mexico border.
Ted Wood

The following timeline untangles the case’s confusing twists and turns:

2008: To resolve lawsuits between the Elephant Butte Irrigation District (in New Mexico) and the El Paso County Water Improvement District (in Texas), the two irrigation agencies and the Bureau of Reclamation signed an “Operating Agreement.” The agreement explained how to split water in Elephant Butte Reservoir, and the protocol for carrying over any excess year to year. Neither Texas nor New Mexico were included in the lawsuit.

2011-2012: New Mexico sued the U.S. and the Elephant Butte Irrigation District over the operating agreement which they said was based on “skewed” baseline numbers. They argued that the agreement shortchanged New Mexico and would result in less surface water for the Elephant Butte irrigation district, forcing farmers to rely on groundwater pumping. The lawsuit was put on hold when Texas sued New Mexico.

January 2013: Texas initiated its lawsuit against New Mexico. The case went directly to the U.S. Supreme Court, rather than being heard in lower courts first, because it involves water and a dispute between states. In January 2014, the court granted Texas’ motion to sue.

February 2014: The Bureau of Reclamation joined the case, siding with Texas. The agency claimed New Mexico’s groundwater pumping threatened both the inter-state Rio Grande Compact and the 1906 Rio Grande Convention with Mexico, which requires that the U.S. deliver 60,000 acre-feet of Rio Grande water to Mexico each year. The Elephant Butte Irrigation District and El Paso County Water Improvement District also tried to join the case, but the U.S. Supreme Court rejected those requests.

April 2014: New Mexico filed a motion to dismiss both Texas’ and the United States’ complaints, arguing that under the Rio Grande Compact, New Mexico’s only responsibility is to deliver water to the Elephant Butte Reservoir, not to ensure that it reaches Texas.

November 2014: The U.S. Supreme Court appointed a Special Master, a judge who oversees fact-finding and a trial in water cases to make recommendations to the court. (Only the Supreme Court can make the final decision in the case.) In 2018, the court dismissed this original judge and appointed and a new Special Master, Judge Michael Melloy.

May 2018: New Mexico filed counterclaims against Texas and the Bureau of Reclamation, stating that the state’s groundwater pumping was a result of poor accounting by the federal government that resulted in unfair allocations of the Rio Grande’s water.

October 2021: Farmers, irrigation districts, and federal, state and city agencies gave testimony. A scheduled second phase of hearings that would have included hydrologists’ testimony was postponed when the parties announced plans to settle the case.

July 2022: The U.S. 8th Circuit Court of Appeals postponed the planned October 2022 trial because a “settlement in principle“ had been reached.

September 2022: Because the parties had not reached a settlement by Sept. 23, the court set a trial date for January 2023.

October 2022: Texas and New Mexico announced that they had reached a settlement. However, the U.S. stated that the proposal violated the Rio Grande Compact and didn’t resolve the U.S.’ claims. The El Paso and Elephant Butte Irrigation Districts also opposed the settlement.

January 2023: A hearing is scheduled to determine whether the proposed settlement is legal.

The Rio Grande flows through Big Bend National Park, where the 1,800-foot vertical barrier of Mariscal Canyon separates Mexico on the right from Texas on the left.
Elliot Ross

Caroline Tracey is the Climate Justice Fellow at High Country News. Email her at [email protected] or submit a letter to the editor. See our letters to the editor policy.