Combined Electrical Imaging and Distributed Temperature Sensing to Characterize Groundwater/surface-water Exchange

Accurate understanding of the spatial and temporal distributions and rates of groundwater/surface-water exchange is critical to addressing numerous hydrologic and engineering problems, including, for example, the calculation of contaminant loading to rivers; stream temperature dynamics and aquatic habitat; and stormwater management and flooding. Hydrogeophysical approaches for both characterization and monitoring, respectively, can provide valuable information to delineate areas of enhanced exchange and to monitor such exchange over time. Here, we review recent case studies from the Columbia River, Washington, USA, and Waquoit Bay, Massachusetts, USA. These studies showcase three highly complementary methods: (1) continuous waterborne electrical imaging; (2) electrical resistivity imaging with fixed electrodes; and (3) fibre-optic distributed temperature sensing.