Geoelectric Characterization of Hyporheic Exchange Flow in the Bedrock-Lined Streambed of East Fork Poplar Creek, Oak Ridge, Tennessee

Abstract

A multimethod geoelectric survey was implemented between January and March 2022 along a 220-m long reach of the bedrock-lined streambed of East Fork Poplar Creek in Oak Ridge, Tennessee to identify locations of surface-water and groundwater exchange and characterize the subsurface flow paths that convey water between the stream and flood plain. A waterborne self-potential (WaSP) survey was completed in January 2022 to measure the electric streaming-potential field in the stream. Electric resistivity tomography (ERT) was performed in March 2022 on the flood plain adjacent to the WaSP survey reach to map the electric resistivity distribution and characterize the hydrogeology and subsurface flow paths that facilitate surface-water and groundwater exchange in the bedrock-lined stream. The combination of WaSP and ERT data support the qualitative interpretation that surface-water and groundwater exchange likely occurs along fractures in outcropping bedrock and along two fault lines that intersect the limestone creek bed.