Relation between proposed developments of water resources and seepage from the All-American Canal, eastern Imperial Valley, California

A two-layer digital model designed for this study indicated that sealing of the Coachella branch of the All-American Canal would cause an eventual increase in seepage from the All-American Canal of about 15,000 acre-feet annually. Sealing of both the Coachella Canal and the segment of the All-American Canal between Pilot Knob and Drop 1 would result in a lessening of seepage rates from the All-American Canal of 57,000 acre-feet in 1985, but of only 39,000 acre-feet in 2030. Sealing both the Coachella and the All-American Canals would reduce the outflow to Mexicali Valley from 120,000 acre-feet in 1980 to less than 9,000 acre-feet in 2030.

The model also indicated that if only the Coachella Canal were sealed, a little less than 40 percent of water pumped from proposed well fields near the All-American Canal ultimately would be derived from increased seepage from the All-American Canal; between 50 and 60 percent of the water pumped would be water that otherwise would flow to Mexicali Valley.