Using hydrogeomorphic patterns to predict groundwater discharge in a karst basin: Lower Flint River Basin, southwestern Georgia, USA

Abstract

Study region: The Lower Flint River Basin (LFRB): a karst catchment in southwestern Georgia, USA. Study focus: Using the U.S. EPA Reach File 3 data set, we generated stream reach azimuths for all tributaries of the Lower Flint River Basin (LFRB) in southwestern Georgia, USA, then compared these results to regional bedrock jointing orientations and stream chemistry (indicating incoming groundwater discharge) in one tributary of the LFRB, Ichawaynochaway Creek. Our objective was to determine if stream bearing might be a useful predictor of increased groundwater discharge in streams of the LFRB where groundwater development has significantly impacted baseflows. New hydrological insights for the region: We identified a dominant N-S trend in 44% of reaches in tributaries of the LFRB with lesser E-W, NNW, NW and NE trends. Bedrock joints and stream reaches in Ichawaynochaway Creek (a tributary of the Flint River) shared similar azimuth trends. When we compared stream reach orientation with known locations of enhanced groundwater inputs (previously detected by Rugel and others) we found that 55% of the time reaches in Ichawaynochaway Creek with increased groundwater discharge followed NW or NNW bearings (mean N49W). Further investigation to replicate these results in other tributaries of the LFRB is warranted and may help inform management strategies which could protect both ecological and economic interests in this region. Keywords: Grondwater discharge, Karst, Water resources, Groundwater-surface water interaction