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25/09 - Séminaire de Marnik VANCLOOSTER - salle de Conférences CERMO à 16h00

par Cédric LEGOUT - 11 octobre 2007

TITRE : Recent advances for characterizing water and solute transport in unsaturated soil
Understanding the flow and transport mechanisms in unsaturated soil is essential to understand the functioning of soil systems, and it is the basis for many flow and transport models currently used in the different domains of environmental sciences, management and engineering. The experimental characterization of flow and transport is subjected to the large space-time variability of soil processes, variables and properties. The traditional experimental techniques, that often have been used to characterize flow and transport, have a small measurement support, which complicates the determination of the space-time dynamics of flow and transport. Hence, there is still a gap that exist between the support scale of experimental characterization techniques and the scale at which flow and transport models are applied. To bridge this gap, new experimental methodologies are needed that increase the accuracy , the resolution and extent of the characterization of flow and transport in soil.
In this seminar, some recent advances are illustrated that have been achieved with direct (dye tracing and solution sampling) and indirect techniques (Electrical Resistivity Tomography, Time Domain Reflectometry and Ground Penetrating Radar) for characterizing flow and transport in soil at the scale of the laboratory soil core and the small field scale.
Improving direct techniques is still needed, as direct techniques continue to be the reference, and as indirect techniques are often insensitive for many essential soil processes. Indirect techniques, which are based on the physical measurement of proxy’s of flow and transport, offer the possibility to increase tremendously the measurement resolution and extent, thereby elucidating the variability of flow and transport at the appropriate scale. We highlight the progress that has been made with these techniques, and identify some strengths, weaknesses and challenges for research in this domain.