One-dimensional numerical scheme to model bed evolution in presence of a side overflow

The present study concerns a one-dimensional numerical model to analyze side weir efficiency by modeling the morphodynamic evolution of river bed during major floods and evaluating its influence on the design discharge to be diverted. The St. Venant-Exner equations are solved by employing a finite volume method, adopting a decoupled procedure. The water depth profiles in the main channel along the side weir are computed by modifying the De Marchi (1934) hypothesis and by evaluating the overflow discharge by means of two different equations in the case of free or submerged overflow. In order to verify the side weir morphodynamic modeling, the present numerical scheme is applied to reproduce the experimental results obtained by Rosier et al. (2006). Finally the model is employed to design a side weir in a real case study.