Characterization of Hydraulic Conductivity with underwater Self-potential Measurements

A designed recharge and recovery system in Aurora Colorado is employed to infiltrate post-treatment water into aquifer and recovered by pumping wells near the infiltration pond. The system suffers from the development of poor infiltration area from near surface clogging layer and functions at about 25% of its predicted capacity. Since streaming potential created by the infiltration of water into aquifer is related with the conductivity distribution, underwater self-potential (SO) survey are taken to map pathways. We first built a 3D synthetic Comsol model which honors the geometric layout of the site to test the validity of this hypothesis. Underwater SP data were generated as measurements from the synthetic model, and then inverted to obtain the distribution of hydraulic conductivity. The results indicate that hydraulic conductivity near the surface can be effectively characterized. Deep aquifer has little impact on the recovery system, and cannot be characterized with the underwater data which is essential taken on the surface of the aquifer. In the end, SP data from the field were inverted to map the infiltration pathways. We found a low conductivity zone in the surface layer at the south of system which was verified by a muddy layer on the surface from visual inspection.