Aquifer characteristics of the pediment south of the Tortolita Mountains, Pima County, Arizona

Abstract

The pediment area south of the Tortolita Mountains was studied by conventional field methods aided by remotesensing images. Investigations of the direction and intensity of fracturing of the quartz monzonite bedrock as well as the structural control of the surface drainage pattern provided the basis for analysis of the hydrologic setting. Water-level measurements, reconnaissance ground-water investigations, and a flow-net analysis were used to determine quantitative aquifer characteristics. Analyses with transparent overlays suggest the quartz monzonite constitutes a potential aquifer where a high degree of correlation exists between the locations of tectonic features, bedrock-controlled stream channels, and productive water wells. The fractured aquifer of the pediment area is recharged by infiltration of surface water through the course sediments of ephemeral stream channels. The Cañada Agua is the major ephemeral stream draining the southeastern section of the Tortolita Mountains. Numerous water wells in a major structural depression traversed and recharged by the Canada Agua serve most of the residents of the pediment area.