Séminaire
Accurate quantification of water movement, both in magnitude and direction, is a necessary component of evaluating any hydrologic system. Groundwater flow patterns are usually determined using a network of piezometers or wells, which can be limited due to logistical or regulatory constraints. In the unsaturated zone, tensiometers can be used to determine unsaturated flow, but require knowledge of site-specific soil moisture dynamics. In either case, piezometers and tensiometers measure potentials from which flow is inferred rather than directly measuring water movement. An emerging alternative is to measure small currents that are generated as water moves through earth material. Measurement of these voltage differences is the basis of the self-potential (SP) method. Signals can be measured using only two electrodes, or through installation of an array of electrodes. I present the results of multiple SP surveys designed to help address open hydrologic questions at multiple temporal (single snapshot, monthly surveys and continuous measurements) and spatial (single tree to hillslope) scales.
thomas.thiebault@upmc.fr