Responses and adjustments of the coastal systems of Dominica (Lesser Antilles) when faced with an extreme event: Hurricane Maria (September 2017) Réponses et ajustements des systèmes côtiers de la Dominique (Petites Antilles) face à un évènement extrême: L'ouragan Maria (Septembre 2017) En Fr

Résumé En

Dominica was hit hard by Hurricane Maria, a category 5 storm when it passed over the island on September 18, 2017. This study aims to characterise the dynamics associated with this event and their consequences in the medium term on the morphology and the coastal structures of this Caribbean island nation. Based on a multi-site approach (9 sites), this study uses varied data (satellite and aerial images, databases, reports, and numerical modelling) and the validation thereof via qualitative observations and topo-morphological surveys carried out in the field 18 months after the hurricane. The high-resolution modelling of the hydrometeorological conditions during the hurricane, the monitoring of the changes in the shoreline, and the field observations brought to light the prevalence of fluvio-sedimentary hazards (torrential flooding and ground movements) over marine hazards (marine flooding and storm swell) in the modification of the coastal landscapes. Phenomena of massive sediment discharge caused considerable damage to the buildings located in low-lying areas and flood plains and to road infrastructure, which hindered access to certain sectors of the island in the post-storm phase for a significant period of time. The more-limited damage of marine origin was exacerbated by the artificialisation of the coast and the establishment of a permanent shoreline. We demonstrate that the impact model for Hurricane Maria for the coastal areas of Dominica is the result of a combination of natural factors with a particular exposure and vulnerability of coastal populations and structures to hydrometeorological risks.