Apport de la modélisation hydro-sédimentaire 1D à l'étude d'une retenue de forme allongée : application à la retenue de Génissiat sur le Haut-Rhône français

摘要

Studying sediment dynamics in dam reservoirs remains an issue because processes are influenced by both natural events and dam management. In this paper, we showed the interest of applying numerical models to complete geomorphological studies based on the analysis of field measurements. In case of an elongated reservoir, one-dimensional (1D) modelling can be sufficient to complete this analysis. One-dimensional codes RubarBE and AdisTS, developed at Irstea Lyon, have been applied to the Genissiat reservoir located on the French Upper Rhone River. These codes enable computing hydraulic parameters useful for the reservoir delineation into homogeneous reaches. Moreover, simulation results showed the specific sediment dynamics of the three main zones describing the reservoir : bedload is prevailing in the free flow segment, graded sand suspension in the upper part of the reservoir, and fine sediment (clay, silt) suspension in the lower one. Eventually, an important interest of the numerical modelling is that predictive scenarii and alternative dam management can be tested easily.