River flood routing by nonlinear muskingum method

The linear form of the Muskingum model has been widely applied to river flood routing. However, a nonlinear relationship between storage and discharge exists in most actual river systems, making the use of the linear model inappropriate. In this paper, a nonlinear Muskingum model is solved using the state variable modeling technique. Various curve fitting techniques are employed for the calibration of model parameters, and their performances within the model are compared. Both linear and nonlinear models are applied to an example with pronounced nonlinearity between storage and discharge. The results show that the nonlinear Muskingum model is superior to the linear one.