Mapping salt tracer penetration into the hyporheic zone with GPR attenuation

Because ground penetrating radar (GPR) attenuation is strongly dependent on effective conductivity, time-lapse changes in attenuation should be able to be used to map conductivity changes. We tested the validity and field practicality of using surface-based multi-offset reflection gathers to map attenuation changes due to the introduction of a saline solution into the hyporheic zone of a mountain stream. A preliminary analysis of our GPR data revealed an unexpectedly high level of system noise in the GPR amplitudes. The noise masked the true conductivity-induced attenuation, and only a broad conductivity trend could be discerned over portions of the GPR transects.