AQUIFER HETEROGENEITY BY MEAN OF ERT AND BORING LOGS: A CASE STUDY IN CEER, SUSQUEHANNA UNIVERSITY

Geophysics is a part of natural science that looks at the physical processes and physical properties of the Earth and its surrounding environment. Electrical resistivity tomography is a geophysical technique that is used to image the subsurface from the electrical measurements that are made at the ground surface. Knowing the makeup of the subsurface, whether it is heterogenous with preferential flow patterns within sand and gravel or homogenous with clay and silt with a defining water table is key in identifying the flow of the groundwater in an area. If groundwater flow patterns can be mapped and identified, then well-drilling and farming practices can be evaluated, and best practices can be used. In this research, 11 electrical resistivity tomography (ERT) surveys, three boring logs were used to investigate the hydrogeological composition of the aquifer, and its interaction with the stream located on the north side of the surveyed area. A groundwater preferential flow toward the middle of the aquifer marked by low electrical resistivity values was found to match the relatively high hydraulic conductive materials visible in the boring logs. Outside this area, the subsurface has relatively higher electrical resistivity values. This indicates that the aquifer is heterogeneous with preferential flow present matching a sandy-gravel with hints of clay and silt zones visible in the boring logs. The lower resistivity material oriented toward the stream, yet the water table was found under the stream bed hence no baseflow supply was provided to the stream.