Each year, almost half of Colorado's annual flow, some six million acre feet, arrives at Imperial Dam, just 150 miles from the river's mouth in the Gulf of California. In non-flood years, the water diverted from Imperial onward irrigates 1.2 million acres in southwestern Arizona, southeastern California, and the Mexican states of Baja California and Sonora. Despite increasing demand for water throughout the Colorado River, low-value, water-intensive crops, especially alfalfa, consume a disproportionate amount of the region's water. Alfalfa is the region's most water-intensive crop, the second-largest crop by area, and of extremely low value.

The region's farmers irrigate over 230,000 acres of alfalfa annually. Nearly three-quarters of the crop grows in California's Imperial Valley. The remaining 25 percent of the region's alfalfa crop grows across the border in the Mexicali Valley and, to a lesser extent, in Arizona's Yuma area. Farmers grow alfalfa because it requires less labor than other crops, can be harvested multiple times during the region's long growing season, and tolerates the poorly drained clay soils of the Imperial and Mexicali valleys.



Alfalfa consumes more water than any other crop below Imperial Dam. Farmers apply as much as seven vertical feet of water to alfalfa crops to promote growth under the hot desert sun. Although it comprises less than twenty percent of the region's irrigated acreage, alfalfa uses over forty percent of the water used by the region's crops. Per acre, alfalfa consumes sixty percent more water than wheat, the region's largest crop; forty percent more water than cotton, the third largest crop by acreage; and seventy-five percent more water than lettuce, the fourth largest crop. The region's alfalfa crop uses more water than all these crops combined.

Although alfalfa consumes an enormous quantity of water, its value per acre is relatively low. According to Imperial County, the Imperial Valley's alfalfa crop value was $687 per acre in 1999. This stands in stark contrast to lettuces, which generated $3,895 to $5,021 per acre. Even cotton, another low-value crop, generated higher values at $959 per acre in the same year.

Alfalfa is a feed crop, especially for dairy operations in the Imperial Valley and California's Central Valley, among other locations. The plentiful, senior water rights enjoyed by farmers in the region permit the cultivation of this water-intensive crop. If price signals were different, it is quite likely that farmers would maximize their returns by turning to other, higher-value crops. Until such changes occur, millions of acres of land will be diverted from the Colorado River to support these low-value feed crops.

Christine Henges-Jeck is a research associate with the Pacific Institute. For more information on water use in the Lower Colorado region, see the Pacific Institute's new report, Missing Water: The Uses and Flows of Water in the Colorado River Delta Region, available online at www.pacinst.org.