Hydrogeology of McMullen Valley, west-central Arizona

Abstract

The hydrogeology of McMullen Valley, west-central Arizona, was investigated using geologic, geophysical, and hydrologic data and a numerical model of the ground-water system. Geologic information and gravity modeling indicate that the main structure of McMullen Valley is a syncline. Basin fill that accumulated in the structural depression is the main aquifer and is divided into upper and lower units. A fine-grained facies in separates the aquifer into shallow and deep systems. A numerical model was used to analyze the ground-water system for both steady-state and transient conditions. The steady-state model aided in evaluating the distribution of hydraulic properties. The transient model was used to analyze system response to pumping stress. Water-level declines are controlled by the distribution of pumpage, specific-yield, and the fine-grained facies of lower basin fill. Significant water-level declines may extend to aquifer boundaries in most of the basin.