On The Impact of a Series of Severe Storms on a Double-Barred Sandy Coast: Dune Erosion and Megacups Embayments

Bruno Castelle (1) , Vincent Marieu (1) , Stephane Bujan (1) , Kristen D. Splinter (2) , Arthur Robinet (3, 1) , Nadia Senechal (1) , Sophie Ferreira (4)

1 EPOC - Environnements et Paléoenvironnements OCéaniques
2 WRL - Water Research Laboratory
3 BRGM - Bureau de Recherches Géologiques et Minières
4 OASU - Observatoire aquitain des sciences de l'univers

The winter of 2013/2014 was outstanding in terms of the available energy to move sediment and caused large-scale unprecedented erosion of the Gironde coast (France), comprising the onset of megacusp embayments cutting the dune with a typical alongshore and cross-shore lengthscale of O (100 m) and O(10 m), and a dune erosion scarp height often exceeding 10 m. Megacusps are found to be coupled to the outer crescentic sandbar and triggered by the outstandingly high-energy, long-period and normally-incident storm wave event Hercules on January 6-7. Our observations indicate that both the antecedent outer sandbar morphology and storm wave characteristics, including period and angle of incidence, govern patterns of beach and dune erosion along open multiple-barred sandy coasts during severe storms.

Domaines: Océan, Atmosphère

Bruno Castelle, Vincent Marieu, Stephane Bujan, Kristen D. Splinter, Arthur Robinet, et al.. On The Impact of a Series of Severe Storms on a Double-Barred Sandy Coast: Dune Erosion and Megacups Embayments. Coastal Sediments 2015, May 2015, San Diego, United States. ⟨hal-01147629⟩