Case study: application of 1-D morphodynamic model to the design of a side weir flow in the Ombrone Pistoiese River Basin

One of the major problems on flood control management is the analysis of river morphodynamics at side weir sites. In the present work the design check of a side weir flow in the Ombrone Pistoiese River in Tuscany (Italy) is undertaken. The analysis is based on a recent morphodynamic model proposed by Catella et al. (2007). Such one-dimensional numerical scheme analyses side weir efficiency by modelling the deposit formation 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 (Catella et al., 2005). The water depth profiles in the main channel along the side weir are computed modifying the De Marchi (1934) hypothesis evaluating the overflow discharge by means of two different equations in the case of free or submerged overflow.