Spatial variability of the hydrodynamic properties of soil at hillslope scale in Cevennes area.

International audienceIn the Cevennes mountainous area, flood processes are due to excess of soil water storage capacity depending on soil porosity, depth and water content at the beginning of the flood (Bouvier et al., 2007; Cosandey, 1994). For hydrological modeling, it is thus important to estimate the hydrodynamic properties of the whole vertical soil profile. In this study, the soils hydrodynamic properties were derived from inverse modeling of soil water content measurements. The efficiency of inverse modeling methods has indeed been proved to be satisfactory in the past years (Köhne et al., 2009; Vrugt et al., 2008; Wöhling and Vrugt, 2011). Assuming that soils have strong heterogeneity, water content was monitored along 4 hillslope transects (68 water content probes) on a small experimental catchment in order to grab the spatial variability of the hydrodynamic properties. The objectives of this study are i) to evaluate the robustness of the hydrodynamic parameters at the event scale depending on the different monitoring stations, ii) to study the spatial variability of the hydrodynamic parameters at the hillslope scale for a given transect, iii) to express this spatial variability as a statistical distribution, to be interpreted in terms of spatial organization