A Reevaluation of Hohokam Irrigation Systems in the Lower Salt River Valley, Arizona

For over a century, large-scale irrigation has been a cornerstone of Ancestral O'Odham (Hohokam) archaeological study. Along the lower Salt River, located in the Phoenix Basin, Arizona, a concerted effort has been made to understand Ancestral O'Odham agricultural production by reconstructing the histories of the largest irrigation systems. In this article, I will discuss an updated reconstruction of ancient irrigation along the lower Salt River. The article begins with an overview of previous Ancestral O'Odham irrigation. Next, the method used to create a new diachronic reconstruction of Ancestral O'Odham irrigation is provided. The method integrates canal signatures seen in historic aerial photography with excavation data and previous canal maps. Synthesized reconstructions of eight major irrigation systems are aggregated into an updated developmental history of irrigation in the lower Salt River Valley. Accompanying this update are discussions of a late Colonial/early Sedentary extremely large flood and standardized irrigation units (SIU).