EVALUATING GROUNDWATER-SURFACE WATER INTERACTIONS USING ERI IN THE ARBUCKLE-SIMPSON AQUIFER

Karst aquifers present challenges in evaluating groundwater-surface water interactions due to the presence of isolated flow paths. The connections between groundwater and surface water were evaluated for the Arbuckle-Simpson aquifer of south-central Oklahoma. Most springs are structurally controlled, but their subsurface geometry is poorly understood. Electrical resistivity imaging (ERI) was employed to investigate the aquifer discharge areas which include springs and artesian wells. The results indicate most discharge features are subvertical with a single connection from depth (>100 m) to the surface. Rotational surveys were employed to determine the strike and dip of conductive features and resistivity modeling evaluated the precision of these measurements. One electrical resistivity image indicates the presence of multiple flow paths to a set of springs which is also demonstrated in temperature and conductivity measurements of spring waters. The overall results are supported by computer modeling of the aquifer and additional geophysical and hydrologic data sources.