Both the Rio Grande and Colorado rivers shrunk in 2021, another bad water year in a two-decade megadrought brought on by a warming Western United States. 

Demands on the rivers — from growing cities, agriculture, wildlife and international treaties — are hitting the reality of a reduced supply of water in both rivers. In August, federal officials declared the first-ever shortage on the Colorado River lower basin, triggering a plan to reduce water usage in several states and Mexico.

For now, the Rio Grande, one of El Paso’s main sources of water, is directly spared from similar unprecedented cuts like those on the Colorado River. But the move has local experts assessing the future of the Rio Grande as both rivers face the same existential question: how will desert communities be able to share less water?

“During dry years, certainly there are more water rights than there is water in either river,” said Alex Mayer, a professor in civil engineering at the University of Texas at El Paso. “What we call a dry year is changing, as we find out more and more about what the climate has been in the past in (the Colorado and Rio Grande) basins, and then also thinking about what future climate change might bring about.”

The Colorado River provides water for 40 million people in both the U.S. and Mexico, while the Rio Grande supplies about 6 million people. About 80% of their surface water goes to crops.

Mayer said that means agriculture as a way of life is uniquely vulnerable, as cities are projected to keep growing and compete for scarce supplies.

“In the Rio Grande basin, the cities on the U.S. side are still growing, slowly. But Ciudad Juárez, which shares at least the groundwater, is growing very rapidly,” Mayer said. “There’s going to be more and more pressure in both basins, for water to go to the cities, and probably less water to go to agriculture.”

Some cities have explored solutions for buying farmer’s water rights along both rivers, which would mean farmers would fallow their crops. Mayer said it raises continued social and economic questions for rural areas.

“I think we have to be careful about whether we want the agricultural tradition, such as it is in our region, to just go away,” Mayer said.

Despite a decent monsoon season, where the region saw nearly three-fourths of its total annual rainfall in three months, the spectre of drought remains in a hotter, drier El Paso.

Long-range forecasts by the National Weather Service show the odds are tilted in favor of La Niña, which usually means a drier, warmer winter in the Western U.S. and a smaller snowpack to feed the rivers. 

The Rio Grande has experienced severe shortages almost every year since 2003, especially for the people below the Elephant Butte reservoir in southern New Mexico and far west Texas. 

Phil King, a consultant for the Elephant Butte Irrigation District, said the writing is on the wall: as temperatures increase, so does stress on the river and water resources. 

“There’s all sorts of complexities, but that’s no excuse for inaction,” King said. “You’re going to have to live with less water. And, you know, people, I think people understand that. They may not realize how much less water they’re going to have to deal with.”

Elephant Butte Reservoir stores Rio Grande water for use downstream in Southern New Mexico, West Texas and Mexico. As of Wednesday, its levels dropped to 5% of its capacity. 

King said those levels are a possible portent for the Colorado’s reservoirs, which fell to record lows at 36% capacity.

“We’re the canary in the coal mine,” King said. “You look at the levels in Elephant Butte, maybe that’s Lake Mead in a couple of years, or Lake Powell.”

Binational waters

King said the first priority for the United States is providing Mexico its share of Rio Grande water: 60,000 acre feet each year, agreed upon in the 1906 Convention. In that agreement, the U.S. and Mexico agreed that in cases of “extraordinary drought,” Mexico would receive a smaller amount, proportional to the amount of water delivered to the U.S. irrigators.

King said a 2008 operating agreement and individual handbooks for each irrigation district take into account compounding years of drought on the region and the river.

In the last 20 years, the United States has only provided the full allotment to Mexico five times because of the extraordinary drought.

“The big problem is drought and climate change. It’s not getting Mexico their water, it’s just that they don’t get very much — none of us get very much anymore,” King said.

Despite a history of discord over water at the southern border, Mexican and U.S. officials said cooperation is key to determining how to deal with the reality of less water in the future. Agencies on both sides of the U.S.-Mexico border are embarking on joint studies and decisions, and calling for binational decisions and investment on the border to manage water shortages.

Both sides take proportional cuts from rivers during extreme drought, an idea laid out in the 1944 treaty regarding rivers, and in later policy negotiations. 

Esteban Moctezuma Barragán, the Mexican ambassador to the U.S., said Mexico will protect the two binational rivers by working on conservation and preventing pollution at the August Border Environmental Forum in San Antonio. The conference was hosted by the North American Development Bank, which is operated by both the U.S. and Mexico, to invest in border communities.

“At no other time in the history of our nations’ has there ever been so great a need to solve a particular issue regarding water supply and drought-related shortage in a post-COVID world with climate change challenges,” Barragán said.

Compare and contrast 

One water expert warned that the Rio Grande does not have as robust a contingency plan for drought management compared to the Colorado River.

John Fleck, who directs the water resources program at the University of New Mexico, wrote several books on the history of the Colorado River. Fleck described the shortage announcement as a “huge warning sign” but also a testament to the improvement of relations between the U.S. and Mexico in the last decade.

“This is a time of great difficulty in water management and international relations, and this collaborative framework between two nations over a shared river helps out everyone,” Fleck said.

Fleck said, however, that an 8-year-old Supreme Court lawsuit over water usage on the Rio Grande between Texas and New Mexico prevents experts and users from coming together for solutions for less water. 

“You are better off having a plan in place for how communities and states that share water are going to share resources, rather than ending up in court, fighting over it,” Fleck said.

The current plan governing the Rio Grande allocations during a drought is the 2008 operating agreement. The agreement was signed by the federal government and two irrigation districts, Elephant Butte Irrigation District and El Paso County Water Improvement District 1, to settle disputes over water in drought years since 2003.

But that plan isn’t universally liked. 

Then-New Mexico Attorney General Gary King sued the federal government over the agreement in 2011, alleging the agency gave too much water to Texas under the agreement.

That lawsuit sparked a state of Texas lawsuit against New Mexico and Colorado in the Supreme Court in 2013 for violations to the 1938 Rio Grande compact. Texas alleges that New Mexico’s pumping of groundwater connected to the Rio Grande means Texas is losing out on its share of water. Texas asked the Supreme Court to make New Mexico pay for the water used over decades.

If New Mexico loses, the court could impose requirements for New Mexico to deliver water owed to Texas and reduce groundwater pumping.

“I worry that the Texas vs. New Mexico and Colorado lawsuit makes it harder to do what we need to do on our Rio Grande,” Fleck said. “One of the guiding principles over on the Colorado River is despite difficulties, they’ve stayed out of court, and that allows you to meet and have good-faith negotiations over hard problems about how we share a shrinking resource.”

Cover photo: The Río Grande seen from Country Club Road at the Texas-New Mexico state line, with Mexico’s Sierra de Juárez in the background, on Aug. 15. (Corrie Boudreaux/El Paso Matters)