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Dynamic Cobble Berm Revetment and Composite Beach Morphodynamics and Behaviour

Séminaire Paul Bayle – post-doctorant, TU Delft

Ce séminaire est proposé par l’axe Environnement, Gestion des Ressources et des Risques, en collaboration avec le groupe H20

Mercredi 22 mars à 11 h 00 Projection Amphithéâtre Nougaro

ID de réunion : 926 3722 7938
Code secret : CAU50x


Composite beaches are natural beaches composed of a lower sandy foreshore and a backshore berm or ridge of gravels, with a distinct separation between the two sediments. Although composite beaches have long been recognised as an effective form of natural coastal protection showing a great degree of stability and adaptability in response to wave attack and sea level rise, they have received much less attention than purely sand or gravel beaches. As a results, their morphodynamics and behaviour under different forcing are poorly understood. Dynamic cobble berm revetments are a sub- category of dynamic revetments which specifically aim to create an artificial composite beach in order to protect sandy coastlines against erosion and flooding. The recent interest in this type of coastal protection triggered some experiments and studies that investigated their behaviour and morphodynamics. Due to the nature of this type of revetment, the experimental results are used here to better understand composite beaches morphodynamics.

The results presented are based on two large scale laboratory experiment (GWK flume, Germany) and one extended field experiment (North Cove, US) where 2D Lidar data, GPS survey and RFID cobble tracking were performed under different wave and water level forcing. This presentation will quickly present the hydrodynamics specificity of composite beaches, and show their highly dynamic stability under energetic conditions and sea level rise. The morphodynamics of the gravel ridge will be explored from large and inter-tidal scale to small, intra-tidal and swash scale, with a particular attention on the sand and gravel interaction within the ridge.