"Eighty years ago, the United States and Mexico worked out an arrangement to share water from the two major rivers that run through both countries: the Rio Grande and the Colorado. The treaty was created when water wasn't as scarce as it is now.
Water from Mexico flows to Texas' half-billion-dollar citrus industry and dozens of cities near the border. On the Mexican side, some border states like Baja California and Chihuahua are heavily reliant on the water that comes from the American side of the Colorado River.
Now, those water-sharing systems are facing one of the biggest tests in their history. Mexico is some 265 billion gallons of water behind on its deliveries to the United States."