Soil hydraulic properties in a marly gully catchment (Draix, France)

Only the multiple radii method was found not suitable in our context due to a large spatial variability in the infiltration properties over small distances. The other methods gave similar estimates of the hydraulic conductivity. The hydraulic conductivity K(h) ranged up to two orders of magnitude. This result confirms the role played by structural voids when the regolith is at near saturation. The dispersion of the estimates of field saturated hydraulic conductivity is larger than unsaturated values. The spatial differences found are explained by the topographical position and by the regolith structure observed for the 6 sites. An analysis based on the ponding time show that the regolith type plays an important role in the dynamic of the runoff production.