One of North America’s major rivers, the Rio Grande—known as the Rio Bravo in Mexico—is facing a critical water crisis, according to new research released Thursday. The river has historically provided for Indigenous communities and served as a route for Spanish explorers, but now its future is uncertain.
The study, conducted by World Wildlife Fund, Sustainable Waters, and university researchers, highlights that the Rio Grande-Bravo basin’s challenges may surpass those faced by the Colorado River. The findings show that only 48% of water consumed in the basin is naturally replenished. The remaining 52% comes from unsustainable sources such as overdrawn reservoirs and aquifers.
“That’s a pretty daunting, challenging reality when half of our water isn’t necessarily going to be reliable for the future,” said Brian Richter, president of Sustainable Waters and senior fellow with World Wildlife Fund. “So we have to really address that.”
The basin supplies drinking water to 15 million people across both countries and irrigates nearly 2 million acres of farmland. Researchers hope their comprehensive accounting of water use—including direct consumption and losses like evaporation—will help policymakers identify where reductions are possible.
Warnings about dwindling flows began in the late 1800s when irrigation projects in Colorado’s San Luis Valley started drying up sections of the river downstream. Today, stretches near Big Bend and Albuquerque often run dry for months at a time.
According to the study, crop irrigation represents 87% of direct water use in the basin. Indirect losses such as evaporation now account for more than half of total consumption—a growing concern as reservoir levels drop.
Farmers are feeling these impacts acutely. In some areas canals dry up by June even though crops need water through October. While summer rains helped central New Mexico farmers this year, others along Texas’ Pecos River and Mexico’s Rio Conchos received no surface water at all.
“A key part of this is really connecting the urban populations to what’s going on out on these farms. These farmers are really struggling. A lot of them are on the brink of bankruptcy,” Richter said.
Between 2000-2019, shortages led to an 18% loss in farmland at Colorado’s headwaters, a 36% loss along New Mexico’s stretch of the Rio Grande, and a 49% loss along the Pecos River tributary shared by New Mexico and Texas. U.S.-side irrigation has declined with fewer farms operating; meanwhile, irrigation in Mexico’s portion has increased significantly.
To find solutions, World Wildlife Fund and Sustainable Waters are working with University of New Mexico researchers to survey farmers about potential responses to ongoing shortages.
Enrique Prunes, co-author and manager of WWF’s Rio Grande Program, noted that approaches vary widely between regions. In Colorado, authorities threaten groundwater shutoffs if aquifer levels don’t stabilize; fees collected from groundwater pumping support programs encouraging farmers to leave fields fallow. New Mexico runs a voluntary fallowing program but may impose stricter measures pending U.S. Supreme Court decisions related to longstanding disputes over river management.
New Mexico currently lags behind on its required deliveries to Texas under an interstate compact; similarly, Mexico owes water deliveries under a binational treaty dating back to 1944—obligations researchers say will become harder to meet as conditions worsen.
Prunes emphasized that environmental considerations must also play a role in any long-term solution: “Policymakers must also consider the environment when crafting solutions.”
