There are seven states in the U.S. and two more in Mexico that depend on the Colorado River’s water. Here, from Sandra Dibble, is a reminder that when shortage descends, it is not just Arizona (as I have been guilty of saying) that takes the first hit:

In Mexico, the first impact of cutbacks on the Colorado River — a basin that links seven U.S. states with northern Mexico — is likely to be felt in the sprawling Mexicali Valley in the neighboring state of Sonora, where the smaller San Luis Valley also relies on deliveries of river water and a series of wells fed by seepage of river water.

If there is a shortage declaration in 2017 (as seems likely), Mexico would see a 50,000 acre foot cutback. Sandra’s story is a good primer on the discussions now underway to clarify who will take the hit.