The Gila River is one of the Southwest's most vital waterways, supplying water to communities, farms, and wildlife while connecting the snow-covered mountains of southwestern New Mexico with the desert landscapes of southwestern Arizona.
In years with ample precipitation, winter snow that accumulates in the Mogollon Mountains and Black Range provides much of the river's spring runoff. That water helps replenish San Carlos Reservoir, which was created by the Coolidge Dam. When full, the reservoir ranks among Arizona's largest lakes.
Snowpack Collapse Drains the Reservoir
Conditions were dramatically different in 2026. Snowfall in the Gila River watershed was exceptionally scarce, leaving mountain snowpack at just 2 percent of the 1991-2020 March median. As a result, streamflow during April reached only 39 percent of normal levels.
By June, required releases of water for downstream agricultural use had further reduced supplies. The reservoir contained less than 400 acre-feet of water.
