The hydrology of Aravaipa Creek, southeastern Arizona

Abstract

The hydrologic system responsible for the perennial flow of Aravaipa Creek in southeastern Arizona consists of a basin filled with sediments and ground water. Ground-water flow through the basin sediments converges at the entrance of Aravaipa Canyon where much of it is forced to the surface due to a restriction in the cross-sectional area of the unindurated sediments. By applying Darcy's law, these sediments are found to have a hydraulic conductivity of up to 1,300 feet/day. The data used in the analysis show that Aravaipa Creek attains its full discharge within 2 miles of the canyon entrance due to a gradual reduction in the transmissivity of the sediments. Precipitation over the watershed is divided quantitatively into evapotranspiration, stream discharge, and pumpage. Ten years of streamflow data divided into base flow and storm runoff show that 8,500 acrefeet/ year become base flow due to ground-water runoff from the valley aquifer. Recharge in the Aravaipa aquifer equals discharge. The discharge, Aravaipa Creek base flow plus pumpage, is 11,600 acre-feet/year, or 2.4 percent of total precipitation. Streamflow statistics, water quality, and current water use are documented, and suggestions for further research are made.