Estimating saturated hydraulic conductivity from ground-based GPR monitoring Porchet infiltration in sandy soil

In this study we present a Porchet infiltrometer experiment monitored by a Ground Penetrating Radar (GPR). The modeled radargram is compared with experiment and a first step into retrieving hydraulic parameters is shown. The experiment was carried out in a quarry of Fontainebleau sand, using a Malå RAMAC system with antennae centered on 800 MHz. Numerical models of the infiltration were made using SWMS-2D, numerical GPR data of the infiltration were computed using GprMax suite of programs. We generated 2D water content profiles associated with a set of Mualem-van Genuchten parameters, at each experimental time step with SWMS-2D. Then we converted those profiles to 2D permittivity profiles using the Complex Refractive Index Method relation, to solve the Maxwell´s equation using GprMax2D. We found that on ground surface GPR is sensitive to the shape of the bulb and to variations of the Mualem-van Genuchten parameters. We propose a first step into an inversion of the saturated hydraulic conductivity by comparing the experimental and modeled two way travel time of the reflection on the top of the infiltration bulb.