Regular flushes of the two Swiss Verbois and Chancy-Pougny dams on the Upper Rhone river are conducted since deposition in the reservoir endanger the city of Geneva. To mitigate suspended sediment concentrations (SSC) peaks due to sediment release and limit sediment trap efficiency, supporting operations are carried out along the river thanks to developed French Genissiat dam. A 1D hydro-sedimentary model is applied to reproduce the fine sediments dynamics in the Genissiat reservoir during the 2012 flushing event. A stratification module is proposed to estimate the vertical concentration profile close to the dam and better reproduce suspended sediment concentrations (SSC) and fluxes at the dam outlets. Possible numerical improvements of the model are proposed to take into account processes related to fine sediment properties such as mud consolidation.