LIttoral ENvironnement et Sociétés (LIENSs) - UMR 7266

« The pre-littoral zone extends from the surf zone to water depths of the order of 20 m and is subjected to exchanges in sediment and suspension matter between beaches and the continental shelf. This part of the coastal zone is intensively exploited by Human for fishing, sand mining or for the installation of marine renewable energy systems. However, the knowledge about the physical processes controlling hydrodynamics and sediment transport in pre-littoral zones is still rudimentary, namely due to the scarcity of field measurements, particularly under extreme events. Thus, the cross-shore extension of the undertow and the fate of sediments eroded in the beach upper part during storms or the relevance of infra-gravity waves in water depths of 10-20 m are still poorly known. Also, the concessions granted to sand mining companies often rely on studies using models that do not correspond to the state of the art (e.g. with respect to wave-current interactions, turbulence produced by waves, infra-gravity waves, etc.) and limited field observations. This PhD thesis aims at improving the knowledge regarding the physical processes that control the hydro-sedimentary dynamics of pre-littoral zones, combining field observations and 3D numerical modeling. »