3- Sands, Channels, Mudflats. Sediment Transport And Morphologic Changes. (The Seine-Aval Scientif

L'environnement géologique et les différentes sources de particules sédimentaires composant les fonds de l'estuaire sont rappelés. La morphologie de l'estuaire est caractérisée en prenant en compte son évolution séculaire. La couverture sédimentaire est ensuite caractérisée ou mise à jour, en privilégiant l'étude des vases. Plus de deux mille échantillons de sédiments ont été analysés, complétés par des campagnes d'imagerie. L'évolution à long terme (échelle du siècle) et à court terme (échelle inférieure à l'année) de la couverture sédimentaire est décrite et interprétée et une prospective sur la possible évolution morphodynamique de l'estuaire est envisagée.

Introduction Chapter I - What sediment is in the lower Seine and where does it come from? Geological context of the Seine Estuary Pre-Quaternary substrate Quaternary deposits in the lower Seine valley The origin of mobile sediment in the estuary Sands and gravels Current contribution from the upstream catchment Current intra-estuary contributions of sands and gravels Current contributions of marine sand Silts and muds The modern contribution of fine particles from the catchment upstream Mud supply from the estuary itself Mud supply from the marine environment Chapter II - The Seine river: an estuarine morphology under human control Upstream from Rouen, a natural estuary From Rouen to Quillebeuf-sur-Seine, a channelized estuary Downstream from Quillebeuf-sur-Seine, a saline estuary The evolution of the estuary from the 19th century to the end of the 1970s The history of the principal modifications The morphological evolution of the downstream estuary up until the 1970s The evolution of the estuary over the course of the last 20 years Modifications from 1980 to 2000 Morphological changes over the last 20 years Chapter III - The surficial sediments of the Seine estuary and their evolution Analytical methodology Fluvial estuary sediments upstream from Rouen Seine channel sediments from Rouen to Quillebeuf-sur-Seine Estuary sediment downstream from Quillebeuf-sur-Seine Downstream estuary sediments in the navigational channel Sediment at the mouth of the Seine The current situation: a map of sediments at the mouth Evolution of sedimentation in the Seine mouth over the last century Seasonal fluctuations in the siltation of the Seine mouth The sediments in the eastern Bay of the Seine A summary of sediment studies in the Seine Estuary and the nearshore area Conclusion and perspectives References Glossary