Innovative in-situ measurements, analysis and modeling of sediment dynamics in Chambon reservoir, France

This paper focuses on siltation processes in an Alpine reservoir, the Chambon Reservoir on the Romanche River. Suspended sediment concentration monitoring upstream the dam leads to the identification of the main contributing hydrological events. Downstream monitoring demonstrates that specific operating conditions (reservoir level, discharge) allow sediment routing throughout the reservoir. In order to elaborate a clear comprehension of sediment processes, field surveys have also been performed in the reservoir. Bathymetry, Velocity field, sediment concentration were monitored. An innovative device has been built in order to identify sediment and flow dynamics inside the reservoir. Some preliminary numerical simulation of sediment dynamics in the reservoir using TELEMAC2D and SISYPHE show encouraging results. Actually modeling could be a useful tool to evaluate sediment management strategy. The main processes involved in suspended sediment transport were identified and their understanding will help to define strategies to reduce sedimentation in Chambon reservoir.