Modélisation des flux sédimentaires charriés dans la baie du Mont-Saint-Michel (Manche, France)

A study of the sediment bedload in the Mont-Saint-Michel bay is presented here. It combines the use of a 2DH numerical model and a pattern of sediment bedload transport established on the analysis of the statements of sidescan imagery combined with a dense groundwork of sedimentary grab samples. Results show the role of tidal currents asymetry in the realistic bioclastic sand transfert from the subtidal environment to the coast and the divergence of sedimentary dynamic between the maritime bay to the West and the tidal delta to the East. This in-shore transfer is responsable of the Holocene prism construction. The model reproduces tidal sedimentary dynamics with the immediate surroundings of the Mont-Saint-Michel. It shows the interest of the modeling of bedload flows in the reconstitution of the sedimentary processes in the filling bays of Manche-Atlantic coast.