Hydrogeology of Butler Valley, Arizona : an artificial recharge and ground-water storage prefeasibility study

Abstract

A USGS finite-difference computer program was used to assess possible artificial recharge and recovery scenarios as part of a technical prefeasibility study of Butler Valley, Arizona. Available hydrogeologic data were compiled and analyzed to build a numerical groundwater flow model of the valley. Input data for the model were gathered from previous work as well as from field studies, including seismic refraction and gravity surveys and aquifer-pump tests performed as part of this investigation. The results of the computer simulations indicate that aquifer storage capacity increases in the upper portion of the basin due to a confined system in the lower portion. The computer model and available geologic data were used to identify potential locations in Butler Valley for artificial recharge operations. The areas along Cunningham Wash and the basin margins appear to be the most favorable for surficial water spreading. Artificial recharge using injection wells, though expensive, appears to be feasible from a hydrogeological standpoint, but chemical interactions between recharge water and native ground water could create undesireable well-screen clogging. Gravity and seismic refraction data collected at the outlet of Butler Valley indicate that ground-water outflow during recharge operations would be minimal because of a shallow subsurface bedrock aquiclude.