Simulation of local infiltration-redistribution-reinfiltration into layered soils

The problem of determining the local infiltration of rainfall into soils characterized by not homogeneous vertical profile is investigated under the condition of pre-existing wetting front which does not allow to apply the conceptual model earlier developed for infiltration starting from initial soil water content Constant with depth. Crusted soils and two-layered soils where either layer may be less permeable are considered. Numerical solutions of the Richards equation are used in order to understand as the shape of the soil water profile progresses with time. The results indicate that the considered process can lead to significant distorsion in the shape of the water content profile and, therefore, a conceptual approach for reinfiltration should be developed by adopting a composite profile scheme in both layers, along the main lines earlier proposed by [5] for the simpler case of a vertically homogeneous soil.