River flow forecasting. Part 4. Applications of linear modelling techniques for flow routing on large catchments

The Multiple-Input Simple Linear and the Multiple-Input Linear Perturbation models are applied for flow routing on converging streams on the catchments of Wuhan, Tongjeizi and Three Gorges in China. These models are applied both in non-parametric form and under the constraint of the gamma function impluse response. Optimum parameters are obtained by the method of ordinary least squares and by Rosenbrock's search technique for the non-parametric and the parametric forms, respectively. The results strongly endorse the adequacy of the Simple Linear Model in the river flow routing. The loss of generality consequent on imposing the constraint of the gamma function impulse response is found to be insignificant. For use in real-time forecasting, an autoregressive updating component is applied.