Overland flow and infiltration modelling for small plots during unsteady rain: numerical results versus observed values

This paper reports the development and application of a two-dimensional model based on an explicit finite difference scheme coupling overland flow and infiltration processes for natural hillslopes represented by topographic elevation and soil hydraulics parameters. This model allows modelling of hortonian overland flow and infiltration during complex rainfall events. Original procedures have been developed in order to simulate complex rainfall events on natural slopes. The accuracy of the results is tested by comparison with experimental field data on the basis of calibrated soil and surface friction parameters. Good agreement between the calculated result and the measured data was found. The scheme proposed was found to be appropriate. The results of tests presented illustrate the effect of microtopography on the distribution of the flow depths, the magnitude and direction of flow velocities and infiltration depths. (C) 2000 Elsevier Science B.V. All rights reserved.