CONJUNCTIVE SURFACE-SUBSURFACE MODELING OF OVERLAND-FLOW

In this paper, details of a conjunctive surface-subsurface numerical m odel for the simulation of overland flow are presented. In this model, the complete one-dimensional Saint-Venant equations for the surface f low are solved by a simple, explicit, essentially non-oscillating (ENO ) scheme. The two-dimensional Richards equation in the mixed form for the subsurface flow is solved using an efficient strongly implicit fin ite-difference scheme. The explicit scheme for the surface flow compon ent results in a simple method for connecting the surface and subsurfa ce components. The model is verified using the experimental data and p revious numerical results available in the literature. The proposed mo del is used to study the two-dimensionality effects due to non-homogen eous subsurface characteristics. Applicability of the model to handle complex subsurface conditions is demonstrated. (C)1998 Elsevier Scienc e Limited. All rights reserved.