Publications scientifiques

La hausse du niveau de la mer liée aux changements climatiques globaux demeure l'une des préoccupations sociétales majeures. L'analyse des données marégraphiques, constituant souvent les seules informations disponibles à l’échelle des décennies, voire des siècles passés, se révèle être un moyen idéal pour parvenir à dégager des tendances sur le long terme. Or, malgré un patrimoine historique marégraphique français conséquent, la majorité de ces mesures est encore sous forme papier et n’est donc pas exploitée.

La façade nord des Hauts-de-France correspond à une frange côtière de 60 km orientée OSO-ENE ouverte sur la mer du Nord. De nombreux bancs sableux sont présents le long de ce littoral où ils forment des corps sédimentaires massifs parallèles à obliques au trait de côte, localisés sur l’avant-côte jusqu’à plusieurs dizaines de mètres de profondeur. Des levés bathymétriques ont été exécutés depuis les années 1830 dans cette région. Les résultats de ces levés hydrographiques sont conservés au format papier dans les archives du Shom.

Recent events like the Xynthia (2010, France) storm illustrate the potentially devastating effect that storm surges can have on the coasts. Nearshore storm surges at the result mainly from two processes: atmospheric surges and wave setup. This paper investigate the relative wave setup contribution in the storm surge signal for energetic events and focusing on two cases: an open beach (Truc Vert beach, France) and a high island protected by a reef lagoon (Tubuai, French Polynesia).

This study focuses on flooding hazards along the Grande Plage of Biarritz. This pocket engineered beach, located in the south west of France, was highly battered by a series of storms during the winter 2013–2014 and experienced great damages to buildings and infrastructures. The vulnerability of this type of beaches to storm impact is assessed using the XBeach surf beat model. For validation purpose, a dedicated spectral wave model is also used on the coastal area to force XBeach at 15 m depth.

Identifying the offshore forcing and breaching conditions that lead to marine inundation is of high importance for risk management. This task cannot be conducted by using a numerical hydrodynamic model due to its high computation time cost (of several minutes or even hours). In the present study, we show how the random forest (RF) classification technique can approximate the numerical model to explore these critical conditions. We focus on the Bouchôleurs site, which is located on the French Atlantic coast and exposed to overflow processes.

As the climate is changing, more applied information on resulting impacts are required to inform adaptation planning . Over the last decade, the amount of information relevant to climate change impact assessment has grown drastically. This can particularly be illustrated in coastal areas, threatened by sea-level rise due to climate change, where a key recent development has been the delivery of precise and accurate topography obtained by Light Detection and Ranging (Li-DAR) at regional and national scales, i.e., respectively, large and small scales.

Rising sea level along with the occurrence of greater and more frequent storms would cause not only coastal flooding, but also beach erosion and shoreline retreat problems. The Almanarre beach along the western Giens tombolo is socio-economically and heavily vulnerable to accelerated sea level rise due to its high touristic value and low-lying topography. Therefore, it is necessary to quantify the impacts of sea level rise (SLR) on the morphodynamics in this area, e.g. to evaluate the relationship between the beach erosion and SLR.

Storm-induced coastal flooding is among the most destructive natural disasters while climate change together with increased populations along the coast will enhance the associated risk. This study presents the comparison of conventional coastal defense schemes against managed realignment schemes in La Faute-sur-Mer, a small village located in the central part of the Bay of Biscay that was severely impacted during Xynthia in 2010.