Large-scale morphodynamics structures in the Arc en Maurienne River (France)

This work focuses on the morphodynamics of a system of alternate gravel bars in an engineered mountainous alpine river, the Arc en Maurienne (France). The experimental site is a selected long reach, which evolved from a natural braided pattern into a reach constrained by two longitudinal dikes, with a curve acting as a forcing point on the sediment motion. Longitudinal changes in the channel width also affected its morphology, leading to the formation of an alternate bar system. Numerical results shows that the Telemac-Mascaret modelling system (TMS) is able to reproduce the morphodynamics behavior observed in a gravel bar-scale reach (approx. 1 km) and the alternate bar patterns observed in a 8 km river reach of the Arc en Maurienne River.