The morpho-sedimentology of an artificial roadstead (Cherbourg, France)

Gwendoline Gregoire (1, 2, 3) , Yann Méar (1, 2, 3) , Emmanuel Poizot (1, 2, 3) , C. Marion (1, 2, 3) , Anne Murat (1, 2, 3) , Bertil Hebert (4)

1 INTECHMER - Institut national des sciences et techniques de la mer
2 CNAM - Conservatoire National des Arts et Métiers [CNAM]
3 LUSAC - Laboratoire Universitaire des Sciences Appliquées de Cherbourg
4 CEFREM - Centre de Formation et de Recherche sur les Environnements Méditérranéens

Because of its size and geographical position, the Cherbourg roadstead appears as a favourable site for Marine Renewable Energy (MRE) industry. As a result, Cherbourg harbour has undergone profound changes (2015 and 2016) due to the installation of industrial infrastructures to service the needs of expanding MRE further offshore. However, little is known about the morpho-sedimentary distribution and associated dynamics of seabed sediments before and after harbour transformations. This study focuses on sedimentary dynamics using detailed morphological and sedimentological analyses based on data acquired before changes (2012). The main map includes a unique bathymetric map (1:35,000) and sedimentary maps showing the percentage of the characteristic grain size fractions of 184 seabed samples. Despite the high tidal conditions, the roadstead construction had a significant impact on the sedimentary facies and distribution. This study provides a basis for future investigations on geomorphological evolution linked to the impact of anthropogenic development.

Mots clés: Cherbourg roadstead; bathymetry; morphodynamic; sedimentology; granulometry; Morphology

Domaines: Géomorphologie; Interfaces continentales, environnement; Hydrologie; Océanographie

Gwendoline Gregoire, Yann Méar, Emmanuel Poizot, C. Marion, Anne Murat, et al.. The morpho-sedimentology of an artificial roadstead (Cherbourg, France). Journal of Maps, 2019, 15 (2), pp.677-685. ⟨10.1080/17445647.2019.1642247⟩. ⟨hal-02370314⟩