A Discrete Modelling of Soil Fragments Transport by Runoff

Gilles Valette, Stéphanie Prévost, Laurent Lucas et Joël Léonard

We aim to model and visualize the evolution of the surface structure of a cultivated soil surface during rainfall. In this paper, we briefly present our model, based on a three dimensional Extended Cellular Automaton, and the different simulated processes. Among these processes, we focus on runoff which is of high relevance as it drives the evolution of the soil surface structure by transporting and depositing the detached fragments of soil and thus inducing an evolution in the granulometry of the surface material. We propose a simple algorithm to model, in a discrete way, runoff and also the transport and deposition of soil fragments according to their size. In that way we are able to derive information about the evolution of soil surface granulometry. A validation of the runoff model is proposed, based on the comparison of the results obtained with results from a numerical solution of the Saint Venant's equations. Although no validation was attempted for transport, simulations yielded visually promising results.

Mots clés

Cellular Automaton, runoff, Saint Venant, soil transport