LUMPING GENERAL KINEMATIC WAVE EQUATION OF SLOPE RUNOFF SYSTEM

Abstract

The method to lump a general kinematic wave equation of the slope runoff system is described. The method is as follows: At first, the basin topography is modeled as a set of slope units using digital topographic information. From the topographic model, the spatial distribution of the upslope contributing area is easily obtained. Secondly, the spatial distributions of the discharge and the flow area are calculated assuming that the rainfall-runoff system is under a steady state. Finally, the storage volume of the slope system is calculated by spatially integrating the flow area and then the lumped relation between the storage volume and the outflow discharge is obtained. The flow area can not be always analytically integrated and some numerical computations are required. Then the technique to reduce the numerical computations is also given.