Potential Tomographic Technique to Detect Soil Water Movements in the Vadose Zone: Laboratory Measurements

Self-potential have been recently employed as a tool for water fluxes detection in the vadose zone. In this work we present the preliminary results of an on-going research being carried out at the Basilicata University. The aim of the research is to improve the detection of water flux-es in the vadose zone by using a self-potential tomographic technique which gives a 4D (3D + time) high resolution image of water movements within the soil subsurface. Several water in-filtration experiments were performed in both field and lab conditions. In this case, particular-ly, the experiments were performed by using a sand box (6.0 x 4.0 x 2.0 meters) which allow to reproduce a medium-large scale natural environment. SP signals were recorded continuous-ly by using an array of 32 unpolarizable electrodes connected to a multiplexed high imped-ance and resolution multimeter. Better results came out from laboratory experiments where most of the so called cultural noise was reduced at a negligible amount. The results of such experiments have proved that SP tomographic images can represent a good tool for monitor-ing the changes of water fluxes under the boundary conditions which are discussed in the work.