GROUNDWATER-SURFACE WATER INTERACTION ALONG COLEMAN CREEK, LITTLE ROCK, ARKANSAS

Coleman Creek is a perennial stream that gently meanders through the University of Arkansas Little Rock campus, downcutting through the Pennsylvanian Jackfork Shale, before emptying into the Fourche Creek, which serves as the primary watershed for much of metropolitan Little Rock. Prior to this study, field observations were made along the creek where seeps were seen emanating from the bank, although the relationship between groundwater within the Jackfork shale and surface water was poorly understood. In this investigation, we utilized geochemical concentrations of various constituents in the groundwater, creek water, and rainfall to quantify the contribution of groundwater to surface water along the creek. Chloride concentrations in the surface waters increased as the creek flowed through campus, despite any other surface water contributions at the time of sampling. Groundwater upgradient of the creek had higher Cl concentrations than the surface water, which supports groundwater contributions to the stream. Additionally, water level data from groundwater wells on the UA Little Rock campus near the creek were used in conjunction with stream discharge data to establish the relationship between Coleman Creek, runoff, and groundwater. Presented here are the results of our investigation depicting groundwater/surface water interactions in an urban environment. This study also enhances our understanding of the hydrology of the Fourche Creek Watershed as anthropogenic activity increases within the drainage basin.