This story was produced by our colleagues at the BBC.

After 30 consecutive months without rain, the townsfolk of San Francisco de Conchos gathered to plead for divine intervention. On the shores of Lake Toronto — the reservoir behind Chihuahua state's most important dam, called La Boquilla — farmers on horseback and their families prayed for a very wet rainy season.

In the congregation is Rafael Betance, who has monitored La Boquilla for the State Water Authority for 35 years. Few know the lake's fluctuations as well as Betance, and he said he's never seen the situation get this dire.

“It's impossible. We are not able to water crops. You can see that the dam lies idle,” he said. “There's no hydroelectric power being generated, and we can't use any water for agriculture. There just isn’t enough.”

But despite the meager supply in Chihuahua, Mexico must abide by the terms of a 1944 water-sharing treaty with the United States. Under the agreement, Mexico must send water from the Rio Grande to Texas. In return, the U.S. sends its own much larger allocation from the Colorado River to supply the Mexican border cities of Tijuana and Mexicali. 

Mexico is in default and has been for much of the 21st century. In April, on his Truth Social site, President Donald Trump accused Mexico of stealing the water and threatened tariffs and possible sanctions unless Mexico sends Texas what it owes.

In Mexico, people in those communities say you simply can't take from what isn't there, and feel trapped by the terms of what they consider to be an outdated agreement that doesn't account for the ravages of climate change.

“So, this is my corn. It's about a week, 10 days off from being ready to harvest,” said Brian Jones, a fourth-generation farmer in the Rio Grande Valley in Texas. “For the last three years, I've only been able to plant half my farm, because I don't have enough irrigation water. We feel that Mexico has not been living up to their part of the treaty.” 

As devastating as the drought has been for farming, the problems extend even further. The reservoir’s critically low level means the little water in it is overheating, killing the lake's marine life, and with it, a once-thriving tourism industry.

In the face of such a litany of problems, the community around San Francisco de Conchos can do little besides bow their heads and pray the rain falls sometime soon.