Investigation of overland flow by incorporating different infiltration methods into flood routing equations

Abstract

In this study, the effect of infiltration on overland flow is explored by incorporating infiltration into the flood routing equations. Particularly, different types of infiltration methods, i.e. the Horton Method, the Integrated Horton Method and the Infiltration Index Method are integrated into the kinematic wave equation. Infiltration capacity curve and infiltration rate are calculated along with the hydrographs. Moreover, the same parameters are determined by incorporating the Integrated Horton method into different forms of Saint-Venant Equations to evaluate the effect of different routing methods on overland flow hydrograph. MacCormack explicit finite difference scheme is employed in solving the coupled infiltration-overland flow differential equations. For each wave routing method, hydrographs of overland flow with infiltration and with no infiltration are compared and discussed under constant and variable rainfall intensities and for different soil types. Results show that infiltration methods affect the overland flow hydrographs significantly.