RICHARD'S EQUATION- ASSISTED FLOOD HYDROGRAPH COMPUTATION BY KINEMATIC WAVE APPROACH

Abstract

The amount of runoff from a given area depends on the rainfall intensity and the infiltration rate. In developing runoff hydrographs from the catchments an excess rainfall distribution is required. In the present study infiltration capacity curve described by Richard's equation has been used for estimating the rainfall excess distribution. The Richard's equation for 1-D unsaturated flow which is a non-linear second order differential equation, has been solved numerically using implicit finite difference scheme. For flood hydrograph computation kinematic wave approach has been applied. This approach can take into account the effects of land use changes, temporal and spatial va<iations in rainfall as well as watershed conditions. In the present work KW equations have been solved by implicit finite difference scheme. The flood hydrographs computed by KW approach have been compared with the observed hydrographs and hydrographs computed by the conventional Nash model. The overall efficiency of KW model has been found to be satisfactory and better as compared to the Nash model. In general the results of application of Richard's equation assisted infiltration for hydrograph computation are quite promising.