HR: 09:15h
AN: H41B-06 INVITED     [Abstracts]
TI: Flow and Transport Monitoring in Soils and Aquifers using Electrical Resistivity Tomography.
AU: * Vanderborght, J
EM: j.vanderborght@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Kemna, A
EM: a.kemna@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Köstel, J
EM: j.koestel@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Oberdörster, C
EM: c.oberdoerster@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Müller, K
EM: k.mueller@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Englert, A
EM: a.englert@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Nguyen, F
EM: f.nguyen@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AU: Schneider, S
EM: Sebastien.Schneider@geol.u-psud.fr
AF: University of Paris XI, UMR-CNRS 8148 IDES Bat. 504, Orsay Cedex, 91405, France
AU: Vereecken, H
EM: h.vereecken@fz-juelich.de
AF: Agrosphere, ICG-4, Forschungszentrum Jülich, Jülich, 52425, Germany
AB: Given the importance of soil and aquifer structures on flow and transport processes, tomographic methods enabling a non-invasive monitoring of these processes are of special interest. In this contribution, we demonstrate some applications of electrical resistivity tomography (ERT) for monitoring flow and transport processes. A first application deals with monitoring of salt tracer transport in the soil or groundwater. During groundwater tracer studies the tracer breakthrough was monitored using local groundwater samplers and ERT in two reference planes perpendicular to the mean flow direction. A numerical study illustrated that conditioning the ERT inversion on local salinity measurements may improve the quality of the ERT images considerably. Because of the small spatio-temporal consistency of groundwater sampler measurements, i.e. groundwater concentration measurements varied over small distances and were not consistent in two consecutive tracer experiments, the use of these measurements for conditioning must be questioned. In a second application, salt tracer transport was monitored with ERT in unsaturated soil monoliths. Here, ERT images were validated against TDR measurements and patterns of an infiltrated dye. Since bulk soil electrical conductivity depends on water content, ERT was applied in a third application to monitor soil water content in a forest plot, where we derived correlations between water content and bulk electrical conductivity from TDR measurements. For all our studies, ERT inversions were strongly determined by the noise of the raw resistivity data. A correct estimation of the data noise and its implementation in the inversion algorithm was found to be essential for a quantitative interpretation of the ERT images. Also incorporating process understanding was found to be important for constraining the inversion. An example hereof is monitoring of seawater intrusion in a coastal aquifer. Finally, we give an example where we use resistivity data to parameterise the process model directly. Resistivities monitored during a tension infiltrometer experiment constrained the estimation of hydraulic soil parameters considerably.
DE: 1835 Hydrogeophysics
DE: 1859 Rocks: physical properties
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Joint Assembly