US and Mexico expand Colorado River Compact

The Colorado River is in the midst of a historic drought.
(Smithsonian photo by Peter McBride)

After months of negotiations, U.S. water district officials said that "the United States and Mexico have agreed to renew and expand a far-reaching conservation agreement that governs how they manage the overused Colorado River, which supplies water to millions of people and to farms in both nations," Dan Elliott reports for the Associated Press. The deal, which was signed yesterday, is known as Minute 323, an amendment to the 1944 Mexican Water Treaty. It will be in effect for nine years.

The U.S. and Mexico first created the Colorado River Compact in 1922; the two nations agreed to work together on river management since the Colorado and its tributaries run through seven U.S. states before passing briefly through Mexico and emptying into the Gulf of California. Because of heavy use, the river usually dries up before it reaches the ocean.

The average annual flow of the river is about 20 billion cubic meters of water; Mexico is promised 1.9 billion cubic meters of that under the agreement. Also, the U.S. must invest $31.5 million in conservation improvements to Mexico's water infrastructure to reduce water loss to leaks and other problems. Mexico, in turn, must develop specific plans for reducing water consumption if the river runs too low to supply everyone's needs. Major consumers of the Colorado's waters would have to agree on their own shortage plan before Mexico produces one. And the deal will extend a previous agreement that both countries will cut back on water use if the river runs low.

Figuring out what to do in case of water shortage was paramount in the agreement. "The Colorado River is in the midst of a prolonged regional drought, and some climate scientists have said global warming is already reducing the amount of water it carries. A study published in February by researchers from the University of Arizona and Colorado State University said climate change could cut the river’s flow by one-third by the end of the century." Elliott reports.