Application of surface-subsurface flow coupled with numerical simulator to runoff analysis in an actual field

A numerical simulator that treats three dimensional, multiphase, surface-subsurface combined flows was applied to actual runoff analysis. A sensitivity study of hydraulic surface/subsurface interaction parameters required in numerical simulation was carried out utilizing short-term data, and a set of parameters that reproduces an actual hydrograph was obtained. To improve reproducibility of the hydrograph, a modification of discretization in expressing riverbed was introduced, so that a more realistic hydrograph is reproduced and a better quantitative estimation about base and side flow is realized. Applying the result of the sensitivity study to long-term runoff analysis, the hydrograph in one year was reproduced satisfactorily with the same hydraulic parameters obtained in the short-term runoff analysis. Copyright © 2000 John Wiley & Sons, Ltd.