But persistent drought, triple-digit heat and a lack of water payments from Mexico to the Rio Grande have visibly taken its toll on the river here, which supplies the town’s 5,000 residents.

The U.S. and Mexico are experiencing another border dispute, and this one is about water. The conflict stems from an 80-year-old treaty where the countries agreed to share water from the Colorado ...

Under terms of the 1944 treaty, Mexico is required to deliver water to the U.S. from six tributaries that feed into the Rio Grande. In exchange, the U.S. delivers water from the Colorado River ...