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.
Roxas, Isabela
On the water supply, Roxas has one of the richest. Residents mostly use shallow and deep wells for reservoir, and usually pumps water through a pump-well system. Some also use electrical-power faucets and Level III water systems (large towers). The main irrigation system for the farmlands are dependent to the Siffu River and other Irrigation System managed by the National Irrigation Administration. The un-irrigated areas greatly depend on rainwater and pumped wells for its water supply.