As one of the most productive agricultural regions in the world, the Imperial Valley receives its water from the Colorado River via the All-American Canal. Rainfall is scarce in the desert region at less than three inches per year and groundwater is of little value.
Physical Features of the Canal
The canal, about 80 miles long, joins the Imperial Dam (and its desilting works) and the 123-mile-long Coachella Canal to complete the All-American Canal System, a component of the Hoover Dam system. This system irrigates as much as 600,000 acres of land in the Imperial and Coachella valleys, producing about one-half of the nation’s annual lettuce crop.
The All-American Canal runs west from the Imperial Dam on the Colorado River and roughly parallels the international Mexico border, giving it its name. The canal supplies about 3.1 million acre-feet (more than 1 trillion gallons) each year to nine cities and 500,000 agricultural acres).
The canal – finished in 1940 – can be credited for much of the Imperial Valley’s agricultural success, but salinity and drainage are ongoing concerns. In 2010, a canal-lining project was completed by the Imperial Irrigation District, which was designed to reduce the annual 67,700 acre-feet of seepage. This water had helped to recharge Mexico’s groundwater basin and Mexico protested the lining, but a court decision and Congressional approval allowed the lining project to go forward. A total of eight hydroelectric plants have been built along the canal since its construction.