Amid severe drought, tensions rise between the U.S. and Mexico over the waters of the Rio Grande

The southern United States and large parts of Mexico have been experiencing a severe drought for several months, leading to tensions between the countries over the delayed release of waters from Mexico into the Rio Grande.

90% of Mexico is currently affected, making the current drought the most severe of its kind since 2011. As reported earlier this year, water supplies to residents in Mexico city are being restricted to several hours a day. In the state of Chihuahua, where not a drop of water has fallen for 8 months, 40% of the population is affected, and the government has  declared a state of "exceptional drought".

Across the border, in Texas, the situation is no better. The Governor of Texas, Greg Abbott, has declared a natural disaster due to the extent of the drought in several counties. The Rio Grande, which forms the border between the southern United States and Mexico, currently has low flow levels, despite being  one of the main sources of water for several American and Mexican states. The stretch between Fort Quitmen and the Presidio is increasingly dry. Two of the main reservoirs on the river are at levels rarely reached: the Falcon reservoir is at 9.9% of its storage capacity, while the Amistad reservoir is at 26% of its capacity.

Over the years, water use has multiplied to cope with population growth and to meet the needs of the factories and farms that have sprung up in the region, encouraged by the economic development of relations between the USA and Mexico since the signing of the 1994 free trade agreement.

Since the 1944 treaty between the two countries, the sharing of the Rio Grande waters has been governed by quotas in the form of five-year cycles. As a result of the drought, by April 2024, the 4th year of the current five year cycle, only 432 million m³ had been delivered by Mexico out of the 1295 million m³ expected within the time period (i.e. 30% of the expected volume).  It should be noted that these quotas were established in the first half of the 20th century, at a time when droughts were already occurring, but when the effects of climate change were not yet known.

Under pressure from certain lobbies, a Republican representative of Texas in the Senate wanted to add provisions to the House of Representatives' 2025 budget bill to make aid to Mexico conditional on compliance with the agreement.

Manuel Morales, Secretary of the Mexican section of the IBWC (the joint water management organization for the Rio Grande and Colorado rivers), stated that Mexico was striving to meet its commitments, but that the water shortage was due to climate change. He pointed out that the 1944 treaty provided for the possibility of shifting water deliveries into the next cycle in the event of a drought episode (article 4), which has already happened twice (1992 and 2002 cycles). Mexico’s President, Claudia Sheinbaum, has pledged to make water issues a priority.

Tensions also exist among American states riparian to the river,bound by the Rio Grande Compact since 1938. Under this agreement, Colorado must deliver an annual quota of water to New Mexico, which in turn must deliver a quota of water to Texas via the Elephant Butte Reservoir. Faced with dwindling resources, farmers in southern New Mexico have increased their water drilling over the past twenty years. Texas subsequently took legal action over the pumping of groundwater, claiming that this practice reduced the amount of water delivered under the agreement. Negotiations took place between the various parties and solutions were about to be proposed when, on June 21, 2024, the U.S. Supreme Court came to reject the text concluded between Texas and New Mexico on water management, ruling that the federal government shoud have a say in any agreement affecting the water treaty with Mexico.