References of "Kaufmann, Olivier"
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See detailA salt tracer test monitored with surface ERT to detect preferential flow and transport paths in fractured/karstified limestones
Robert, Tanguy ULg; Caterina, David ULg; Deceuster, John et al

in Berichte der Geologischen Bundesanstalt (2012, September), 93

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See detailA Saline Tracer Test Monitored with ERT to Detect Preferential Flow/Transport Paths in Limestones
Robert, Tanguy ULg; Caterina, David ULg; Deceuster, John et al

in EarthDoc - Near Surface 2010 – 16th European Meeting of Environmental and Engineering Geophysics (2010, September 07)

The success of a tracer test highly depends on the number and the localisation of the sampling wells. When preferential solute transport paths are expected, one needs to set up carefully the tracer test ... [more ▼]

The success of a tracer test highly depends on the number and the localisation of the sampling wells. When preferential solute transport paths are expected, one needs to set up carefully the tracer test to recover information such as the local groundwater flow direction and an estimate of the transport velocities. In this work, we used electrical resistivity tomography (ERT) to monitor a saline tracer test. This experiment was performed in fractured limestones where high transport velocities and strong dilution effects were expected. This required a continuous injection and fast ERT acquisition. Two different salt concentrations (40 and 160 g/l) were injected to deal with dilution effects. We also tested the resolution and the depth of investigation of our dipole-dipole sequence by changing the electrode spacing. Two transversal (and a longitudinal) profiles were placed every 20 m from the injection well. During the first (second) test, a maximum of -8 % (-16 %) change of electrical resistivity was observed in the nearest ERT profile while no change occurred in the other ones. We were then able to estimate the transport velocities in addition to the local groundwater flow direction even if the dilution effects were important. [less ▲]

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See detailUsing Electrical Resistivity Tomography and Self-potential Methods for Wells Implementations in Fractured Limestones
Robert, Tanguy ULg; Dassargues, Alain ULg; Brouyère, Serge ULg et al

in EarthDoc - Near Surface 2009 – 15th European Meeting of Environmental and Engineering Geophysics (2009, September 09)

Electrical resistivity tomography (ERT) and self-potential (SP) investigations were conducted in fractured limestones in Belgium. The aim of this study was to find suitable positions for high yield water ... [more ▼]

Electrical resistivity tomography (ERT) and self-potential (SP) investigations were conducted in fractured limestones in Belgium. The aim of this study was to find suitable positions for high yield water wells. Large ERT profiles (640 meters) allowed us to image the resistivity distribution of the first 60 meters of the subsurface and to detect and characterize (in terms of direction, width and depth) fractured zones expected to be less resistive. Data errors, DOI indexes and sensitivity models were analysed in order to calculate the depth of investigation of ERT and to avoid the misinterpretation of the resulting images. Self-potential measurements were performed along electrical profiles to narrow the possible locations given by the electrical images. Some negative anomalies possibly related to preferential flow were detected. ‘Ground truth’ geological data as well as pumping tests information gave us a way to assess the contribution of geophysics to a drilling programme. Wells implemented in low resistivity zones associated with SP anomalies have very high yields. Inversely, wells drilled in resistive zones or outside SP anomalies have poorer capacities. An apparent coupling coefficient between SP signals and differences in hydraulic heads was also estimated in order to image the water table. [less ▲]

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