A Nonlinear Hydrologic System Response Model

The effects of the physical factors responsible for the transformation of rainfall excess into direct runoff have been simulated by the action of a conceptual nonlinear reservoir. A nonlinear differential equation of the basin response has been derived. In the absence of the existence of an analytic solution for the system response equation, solutions by means of an electronic analog computer and a numerical method are presented. Model parameters are found to be well correlated with basin, main channel, and rainfall characteristics for seven east central Illinois basins. The consistency of the results obtained from an analysis of storms over these basins indicates that the proposed model may be adopted for nonlinear simulation of the hydrologic system response.