Electrical resistivity tomography applied to groundwater aquifer at downstream of Chih-Ben Creek basin, Taiwan

Groundwater resource investigations primarily involve inferring groundwater levels and recharge sources from factors such as the distributed location and range, subsurface geological structure, and flow paths of groundwater sources. This study conducted an investigation on the underground aquifer at the downstream of the Chih-Ben Creek basin, Taiwan. In addition, convenient, rapid, and accurate two-dimensional electrical resistivity tomography (ERT) was employed for evaluations. The cross-sectional ERT image indicates that the low-resistivity region in the stratum at survey line CB01 may be a groundwater deposit or fracture zone. This region can be divided into three major segments. The segment that is 0–50 m from the survey line exhibits a decreasing trend and is thus inferred to be a recharge source. Survey line CB02 can be generally divided into four layers, with the second layer containing a greater amount of groundwater. This layer is an aquifer with a depth of approximately 25–100 m below the ground surface and 75–100 m in thickness. The base of the aquifer slopes toward the east and primarily possesses a lithological composition of slate and sandstone with explicit and fractured joints.