“Mega drought” on the border fuels disputes between the US and Mexico over water shortages

The United States and Mexico are fighting for their dwindling shared water supplies after years of unprecedented heat and insufficient rainfall.

Map showing the southwestern United States and northern Mexico
The Colorado River Basin.
U.S. Geological Survey

Sustained drought in the lower-middle Rio Grande since the mid-1990s means that less Mexican water flows to the United States. The Colorado River basin, which supplies seven states in the United States and two in Mexico, also is at record low levels.

A 1944 treatise between the United States and Mexico governs the water relations between the two neighbors. According to our research, the International Boundary and Water Commission he established to manage the 724,205 square kilometer basins of Colorado and Rio Grande has done it skillfully.

This management kept the water relations between the United States and Mexico, for the most part, free of conflict. But it masked some well known underlying stresses: a demographic boom on both sides of the border between the United States and Mexico, climate change and the aging of hydraulic works.

1944 al 2021

The mostly semi-arid border region between the United States and Mexico receives less than 18 inches of annual rainfall, and large areas are less than 12 inches. That’s less than half the average annual rainfall in the United States, which is mainly warm.

The 1940s, however, were a time of unusual abundance of water in the treaty rivers. When American and Mexican engineers wrote the 1944 water treaty, They did not foresee today’s prolonged mega-drought.

They also did not anticipate the rapid growth of the region. Since 1940, the population of the 10 pairs of larger cities that straddle both sides of the U.S.-Mexico border it has multiplied almost by twenty, from 560,000 people to about 10 million today.

This growth is driven by a booming water-dependent manufacturing industry in Mexico that exports products to US markets. Irrigated agriculture, ranching and mining compete with growing cities and expanding industry for water scarcity.

Two photos showing the drops in the water level of Lake Mead
Lake Mead circa 1950, on the left, and Lake Mead in June 2021. Cliffs show substantial drop in water level.
William M. Graham/Archive Photos/Getty Images y Ethan Miller/Getty Images

Today simply not enough to meet demand in border areas governed by the 1944 treaty.

Three times since 1992, Mexico has failed to fulfill its five-year commitment to send 1.75 million acre-feet of water across the border to the United States. Each acre-foot can supply an American family of four for one year.

Water conflicts

In the fall of 2020, the crisis erupted in the Rio Grande Valley after years of mounting tensions and sustained droughts that endanger crops and livestock in both the United States and Mexico.

In September 2020, Texas Governor Greg Abbott stated that “Mexico owes Texas a year’s worth of Rio Grande water”. The following month, workers in Mexico discharged water from a dammed portion of Mexico’s Rio Conchos destined to cross the border to partially pay Mexico’s 345,600 acre-foot water debt to the United States.

Frustrated farmers and protesters in the Mexican state of Chihuahua they clashed with Mexican soldiers sent to protect workers. A 35-year-old farmer’s wife and mother of three have died.

Mexico also agreed to transfer the water stored in the Amistad dam to the United States, fulfilling its obligation just three days before the October 25, 2020 deadline. That decision satisfied its water debt to the United States under the 1944 treaty, but jeopardized the supply of more than a million Mexicans living downstream from the Amistad dam in the Mexican states of Coahuila and Tamaulipas.

Soldiers in riot gear stand behind barbed wire-wrapped wax
The Mexican National Guard stands guard at the Las Pilas dam after 2020 clashes with farmers in the state of Chihuahua.
Christian Chavez/AP Photo

The United States and Mexico committed to review the Rio Grande water rules of the treaty in 2023.

The dilemma of drought on the Colorado River is just as dire. The water level in Lake Mead, an important reservoir for communities in the lower Colorado River basin, has fallen almost 70% in 20 years, threatening the water supplies of Arizona, California and Nevada.

In 2017, the United States and Mexico signed a temporary “shortage sharing solution”. That agreement, forged under the authority of the 1944 treaty, allowed Mexico to store some of its treaty water in US reservoirs upstream.

Save a tense treaty

Water shortages along the US-Mexico border also threaten the natural environment. As water is channeled to farms and cities, rivers are deprived of the flow necessary to maintain habitats, fish populations, and the general health of rivers.

The 1944 water treaty was silent on conservation. Despite all its strengths, it simply allocates water from the Rio Grande and Colorado rivers. It does not consider the environmental side of water use.

But the treaty is reasonably elastic, so its members can update it as conditions change. In recent years, conservation organizations and scientists have promoted the environmental and human benefits of restoration. The new Colorado River agreements now recognize ecological restoration as part of treaty-based water management.

Environmental projects are underway in the lower Colorado River to help restore the river delta, emphasizing native vegetation such as willows and aspens. These trees provide habitat for birds at risk such as the yellow-billed cuckoo and the Yuma clapper, and for numerous species that migrate along this desolate stretch of the Pacific flyway.

Map of the United States-Mexico border with a highlighted area
Rio Grande Basin.
U.S. Geological Survey

Currently, no such environmental improvements are planned for the Rio Grande.

But now they are being applied other lessons learned in the Colorado to the Rio Grande. Recently, Mexico and the United States created a permanent binational advisory body for the Rio Grande, similar to the one established in 2010 to monitor the health and ecology of the Colorado.

Another recent agreement allows each country to monitor the other’s Rio Grande water use using common diagnostics such as Riverware, a dynamic modeling tool for monitor water storage and flows. Mexico also agreed to try to use water more efficiently, allowing more to flow to the United States.

Newly created joint expert teams will study treaty compliance and recommend additional changes needed to manage the climate-threatened waters along the US-Mexico border sustainably and cooperative.

Incremental treaty modifications like these could palpably reduce last year’s tensions and revitalize a historic US-Mexico treaty that is collapsing under enormous pressure from climate change.

This article was translated by The financial.

Robert Gabriel Varady, Research Professor of Environmental Policy, University of Arizona; Andrea K. Gerlak, Professor, School of Geography, Development and Environment, University of Arizona, and Stephen Paul Mumme, Professor of Political Science, Colorado State University

This article was originally published on The Conversation. read the original.


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