Agriculture in the prehistoric Southwest
After the Hohokam disappeared, Spanish explorers of the 16th century noted the use of canal irrigation in only two areas of the Southwest: eastern Sonora, primarily practiced by the Opata and Lower Pima, and among the Pueblos of northern New Mexico. Irrigation by the Opata and Pueblos had different objectives. In Sonora, with a long growing season, two crops of maize a year were grown in river valleys. The spring crop during the dry season was dependent upon irrigation; the summer and fall crop during the rainy season utilized irrigation to supplement rainfall. The necessity of irrigation probably required a high level of social organization. In New Mexico, with only one crop of maize per year possible, irrigation was supplemental and the lesser dependence on irrigation implies less social organization than in Sonora.
Mexicali
In 1900, the U.S.-based California Development Company received permission from the government of Díaz to cut a canal through the delta's Arroyo Alamo, to link the dry basin with the Colorado River. To attract farmers to the area, the developers named it the "Imperial Valley". In 1903, the first 500 farmers arrived; by late 1904, 405 km² (100,000 acres) of valley were irrigated, with 10,000 people settled on the land harvesting cotton, fruits, and vegetables. The concentration of small housing units that straddled the border was called Calexico on the U.S. side and Mexicali on the Mexican side. Led by "Los Angeles Times" publisher Harry Chandler, one company controlled 800,000 hectares of land in northern Baja California by 1905, and began to build the irrigation system for the Valley. However, instead of using Mexican labor to dig the ditches, Chandler brought in thousands of Chinese laborers. Mexicali became culturally Chinese influenced.