A multi class classes sedimentary dynamic model to calculate erosion and deposition : flux in the fresh water ; application to the low Rhone region.

El Ganaoui O., Amielh M., Boyer P., Anselmet F. 28th congress of SIL, Melbourne, Australia, 4-10 February 2001. Proceedings of the International Association of Theoretical and Applied Limnology, Volume 28.

In the freshwater radioecological quality model, the radioecology is linked to the sedimentary dynamic through the deposition and erosion flux. The estimates of these flux with a dynamic sedimentary model requires site and laboratory experiments. Generally, these models are based on two global approach relatives to one classes of particles, the first is linked to the two critical shear stress of deposition and erosion and the second to the equilibrium suspended sediment concentration. Meanwhile, a natural water flow is characterized with a wide and continuous range of different granulometric classes and the deposition for one class can come with the erosion of another class, so it’s interesting to elaborate a model witch integrate several classes. In this context, we present an experimental method to determine the main classes, their critical shear stress of erosion, the erosion rate and the settling velocity associated. These parameters are used in a multi class classes sedimentary dynamic model. The results of an application to the low Rhone region in fresh water and the comparison with a classical model will be presented and discussed.