Study warns of ‘existential water crisis’ in the Rio Grande Basin

A major new study on the nearly 1,900-mile long Rio Grande Basin — from the San Luis Valley into the Gulf of Mexico — shows a “severe water crisis emerging” with total reservoir storage in decline at around 4.24 million acre-feet or 26 percent of capacity.

The study brings together detailed water consumption estimates of surface and ground water use throughout the basin and concludes “a likely outcome will be continued loss of farmland due to financial insolvency from lowered crop production and other factors including the aging of farmers and lack of affordable farm labor,” without urgent action.

“Climate scientists have reframed the long-running drought as the onset of long-term aridification and are forecasting additional river flow diminishment of 16-28% in coming decades as the climate continues to warm,” the study notes.

The authors’ analysis shows that during 2000–2019, Colorado lost 18 percent of its farmland in the Upper Rio Grande Basin, New Mexico lost 28 percent along its Rio Grande sub-basins, and the Pecos River sub-basin lost 49 percent.

Further drying puts farmers and cities who rely on the Rio Grande in an “existential water crisis.”

Brian Richter, one of the authors of the study, says San Luis Valley farmers are central to the development and implementation of solutions for the rapidly drying Rio Grande given that “the vast majority of the direct human consumption of water in the SLV takes place on irrigated farms.”

Researchers estimate that the present level of over-consumption of both surface and groundwater in the Valley is approximately 11 percent. “That means that water consumption needs to be reduced by that percentage,” Richter said.

Richter is president of Sustainable Waters and senior freshwater fellow for the World Wildlife Fund. The two organizations teamed with researchers to provide a full accounting of the consumptive uses as well as evaporation and other losses within the Rio Grande Basin. 

The Rio Grande stretches nearly from the San Luis Valley through New Mexico, El Paso, Texas, and empties into the Gulf of Mexico. It provides drinking water for more than 4 million in Colorado, New Mexico and Texas, and 11 million people in Mexico, the study notes. More than 1.9 million acres of irrigated farmland is tied to the Rio Grande.

The study, “Overconsumption gravely threatens water security in the binational Rio Grande-Bravo basin,” relies on data from annual runoff volumes, municipal and commercial consumptive use estimates from the U.S. Geological Survey, and reservoir storage levels, among other data sets.

Snowmelt runoff has decreased 17 percent over the past 25 years, according to the report. At the same time, total direct water consumption has been increasing since 2000, largely due to increasing water usage by farmers in Mexico.

When comparing challenges of Colorado River users to the Rio Grande, researchers say the “water crisis facing the RGB is arguably more severe and urgent than the CRB,” given the fact groundwater in the San Luis Valley has been depleted at a rate of 89,000 acre-feet per year; New Mexico has a water debt to Texas; and Mexico has a mounting water debt to the U.S. under a 1944 treaty that is causing political tension between the two countries.

The Upper Rio Grande here at the end of 2025 is benefitting from heavy October rains that materialized across the southwest and provided a stopgap to what were some of the worst summer river flows ever recorded on the river.

Management of the Upper Rio Grande Basin will be back in the spotlight come January 2026 when Colorado Water Court Division Three takes up the Fourth Amended Plan of Water Management for Subdistrict 1 of the Rio Grande Water Conservation District. The new strategy calls for a groundwater overpumping fee of $500 per acre-foot any time an irrigator in Subdistrict 1 exceeds the amount of natural surface water tied to the property of their operation. The rule punishes farmers who do not have natural surface water coming into their fields but instead rely solely on groundwater pumping for their crops.

The whole point of the plan for the agricultural-rich area of the San Luis Valley is to let Mother Nature dictate the pattern of how irrigators in Subdistrict 1 restore the unconfined aquifer and build a sustainable model for farming in the future.

Richter credits Colorado and irrigators in the Valley for taking steps to address the Rio Grande. The proposed $500 fee for overpumping in Subdistrict 1, he says, “is going to set off a lot of change in the Valley, because many/most farmers won’t be able to continue producing the same crops they’ve been growing in recent years.”

“Colorado has definitely taken some important steps, and manages its water resources far better than New Mexico or Texas,” Richter says. “But Colorado still has not been able to reduce pumping to anywhere near the needed degree, so it’s no surprise the aquifer continues to decline.”

The study looks at crops grown along the Rio Grande and how agricultural fields account for 87 percent of direct water consumption. “Overall, agricultural consumption is nearly seven times the volume of all other direct uses combined.”

Alfalfa and grass hay – water-intensive crops that dominate the landscape in the Valley and in Northern and the Middle Rio Grande of New Mexico – account for nearly 45 percent of the irrigation water consumed along the Rio Grande Basin. A shift to less-intensive crops, as the Rye Resurgence Project advocates, and a moratorium on new wells in over-drafted areas of basin in New Mexico and Texas, are necessary first steps to addressing the Rio Grande’s challenges, according to researchers of the study.

“Potatoes might be one of the few crops that remain sufficiently profitable to persist in the Valley,” says Richter. “If those transitions to other crops or to permanent farmland retirement lead to reduced water consumption to the level needed (11 percent), there is hope that the (unconfined) aquifer can be rebalanced with natural replenishment. However, it will require a greater level of pumping reductions to enable the aquifer to recover to the level required by the state engineer.”