WATER SECURITY Water Is the Other U.S.-Mexico Border Crisis, and the Supply Crunch Is Getting Worse
The United States and Mexico are aware of the political and economic importance of the border region. But if water scarcity worsens, it could supplant other border priorities. The two countries should recognize that conditions are deteriorating and update the existing cross-border governance regime so that it reflects today’s new water realities.
Immigration and border security will be the likely focus of U.S.-Mexico relations under the new Trump administration. But there also is a growing water crisis along the U.S.–Mexico border that affects tens of millions of people on both sides, and it can only be managed if the two governments work together.
Climate change is shrinking surface and groundwater supplies in the southwestern U.S. Higher air temperatures are increasing evaporation rates from rivers and streams and intensifying drought. Mexico is also experiencing multiyear droughts and heat waves.
Growing water use is already overtaxing limited supplies from nearly all of the region’s cross-border rivers, streams and aquifers. Many of these sources are contaminated with agricultural pollutants, untreated waste and other substances, further reducing the usability of available water.
As Texas-based scholars who study the legal and scientific aspects of water policy, we know that communities, farms and businesses in both countries rely on these scarce water supplies. In our view, water conditions on the border have changed so much that the current legal framework for managing them is inadequate.
Unless both nations recognize this fact, we believe that water problems in the region are likely to worsen, and supplies may never recover to levels seen as recently as the 1950s. Although the U.S. and Mexico have moved to address these concerns by updating the 1944 water treaty, these steps are not long-term solutions.
Growing Demand, Shrinking Supply
The U.S.-Mexico border region is mostly arid, with water coming from a few rivers and an unknown amount of groundwater. The main rivers that cross the border are the Colorado and the Rio Grande – two of the most water-stressed systems in the world.
The Colorado River provides water to more than 44 million people, including seven U.S. and two Mexican states, 29 Indian tribes and 5.5 million acres of farmland. Only about 10% of its total flow reaches Mexico. The river once emptied into the Gulf of California, but now so much water is withdrawn along its course that since the 1960s it typically peters out in the desert.
The Rio Grande supplies water to roughly 15 million people, including 22 Indian tribes, three U.S. and four Mexican states and 2.8 million irrigated acres. It forms the 1,250-mile (2,000-kilometer) Texas-Mexico border, winding from El Paso in the west to the Gulf of Mexico in the east.
