Hydrological processes identification by the combination of environmental tracing with time domain reflectometry measurements

This study begins with the application of environmental tracing in order to identify hydrological processes in the Haute-Mentue basin. The application of a three-component model, based on concentrations of silica and calcium demonstrates that the groundwater and soil water dominate streamflows. Mixing models identify volumes, but not water pathways. In this context, in order to specify which physical properties or mechanisms are responsible for the important contribution of subsurface flows, an experiment based on a time domain reflectometry system and additional measurements within the basin (piezometers and rainfall simulator) was conducted. The association of these experiments allows demonstrating that preferential flows are certainly responsible for the important contribution of soil water. Furthermore according field observations and a rainfall simulator experiment, it seems that macropores are at the origin of these preferential flows.