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.
Zanja Madre
The Zanja Madre (English: "Mother Ditch") is the original aqueduct that brought water to the Pueblo de Los Angeles from the Río Porciuncula (Los Angeles River). The original open, earthen ditch was completed by community laborers within a month of founding the pueblo.
This water system was used for both domestic uses and irrigation to fields west of town. This availability of water was essential to the survival and growth of the community founded here. were built to improve the system after 1884. Eventually the system did not supply enough water to keep pace with population growth and irrigation demand. The system was abandoned by 1904 though portions were still used for storm water purposes.