Nonlinear kinematic wave approximation for water routing

Abstract

Herein a simple numerical model for both overland and channel water routing is presented. A second‐order nonlinear scheme is developed to solve the kinematic wave equation with the boundary condition of time variant inflows. The numerical solutions agree very well with analytical solutions which are available for some particular cases. This model includes the effects of rainfall on flow resistance and simulates hydrographs which agree very well with experimental results for both constant rainfall and variable rainfall cases. The interesting phenomena of ‘pip’ and ‘dip’ in overland flow hydrographs are successfully simulated. These phenomena are found to be the results of sudden changes of flow resistance due to ceasing or starting of rainfall. The same routing procedure for overland flow is employed to route flow in natural channels.