HR: 09:00h
AN: H41H-05    [Abstracts]
TI: Estimation of the Unsaturated Hydraulic Soil Properties From Joint Inversion of Tension Infiltrometer and ERT Measurements: Numerical Experiments
AU: * Schneider, S
EM: sebastien.schneider@u-psud.fr
AF: University of Paris XI, UMR-CNRS 8148 IDES, Bât. 504, Orsay, 91405, France
AU: Vanderborght, J
EM: j.vanderborght@fz-juelich.de
AF: Agrosphere Institute, ICG-IV, Forschungszentrum J\"ülich GmbH, J\"ülich, 52425, Germany
AU: Kemna, A
EM: a.kemna@fz-juelich.de
AF: Agrosphere Institute, ICG-IV, Forschungszentrum J\"ülich GmbH, J\"ülich, 52425, Germany
AU: Pessel, M
EM: marc.pessel@u-psud.fr
AF: University of Paris XI, UMR-CNRS 8148 IDES, Bât. 504, Orsay, 91405, France
AU: Coquet, Y
EM: Yves.Coquet@agroparistech.fr
AF: UMR INRA/INAPG Environment and Arable Crops, Paris-Grignon, Thiverval-Grignon, 78850, France
AB: An accurate and time-efficient estimation of unsaturated hydraulic soil properties in the field remains a challenge. Tension-infiltrometry is often used to determine unsaturated hydraulic soil properties and their spatial variability in the field. Due to capillary flow, a 3-D wetting bulb, which depends on the unsaturated hydraulic soil properties, the radius of the infiltrometer disk, and the applied water tension, develops under a tension infiltrometer. Electrical resistivity tomography (ERT) offers the possibility to image the spatial distribution of bulk soil electrical conductivity, which is related through a petrophysical model to the soil water content. Therefore, ERT data contain information about the 3-D structure of the wetting bulb, which may be exploited to infer hydraulic soil properties. A combination of tension-infiltrometer and ERT data for an inverse estimation of the soil hydraulic parameters was tested in a numerical experiment. Both 3-D water flow and electrical potential fields were simulated with the SWMS_3-D model using the van Genuchten hydraulic functions and the Rhoades petrophysical model. Simulated infiltration and simulated apparent electrical resistivities were subsequently inverted using the PEST software. Inversion of the combined infiltration and ERT datasets showed that the hydraulic parameters could be inverted from a single infiltration experiment, which is not possible when only infiltration data are used in the inversion. Also petrophysical parameters could be inverted simultaneously with hydraulic parameters from the combined ERT-infiltrometer data. These results demonstrate the potential of the method by considering additional information about the structure of the wetting bulb which is contained in ERT data.
DE: 1835 Hydrogeophysics
SC: Hydrology [H]
MN: 2007 Fall Meeting