An assessment of recharge from irrigated agricultural land in Harquahala Plains, Arizona

Abstract

In the current study, the Harquahala Basin was selected as an appropriate site for research into the component of recharge resulting from irrigation return flow to an aquifer system. Agriculture in this area commenced in the early 1950s, and intensive irrigation has resulted in perched water tables and zones of cascading water at various locations throughout the valley. In these areas, the quality of the perched water was significantly poorer than the regional aquifer system, leading to the hypothesis that these zones contained irrigation return flow. Sufficient pumpage information was available to permit the development of a numerical model of the basin utilizing MODFLOW. After calibration and validation utilizing data from 1954, 1966, and 1974, it appears that, in the Harquahala area, 20 percent of the applied irrigation water eventually returns to the water table as recharge.