As drought deepens in the West and the water used by farms and people alike dwindles, farmers in Arizona and California are bracing for cutbacks in the two major federal systems that supply irrigation and drinking water to millions of people.

Water storage is shrinking with no snowpack to replenish reservoirs managed by the Bureau of Reclamation in California and Arizona. Shasta Lake in northern California is about half full while lakes Mead and Powell, the two giant reservoirs designed to contain more than 50-million-acre feet of water behind Hoover and Glen Canyon dams, respectively, are precariously low with under 20-million-acre feet of total storage combined.