Le risque naturel côtier sur la communauté d'agglomération du Havre (Haute-Normandie) : Une évaluation des aléas.

Abstract : Le Havre suburb is located between the Seine estuary and the chalk plateau of the Paris basin NW boundary. This coastal territory is submitted to typical natural hazards observed on coastal areas that are coastal floods and cliffs erosion. The study use data from aerial photographs and LiDAR surveys. The lower part of Le Havre town, built around historical tidal docks, is sensitive to coastal floods hazard. Three urban coastal floods occurred in 1981, 1983 and 1984 resulting to a combination between high water level of spring tides and surges produced by low air pressure and/or strong winds. The aim is to map, in the lower part of Le Havre town, the areas of potential overflow and flood. Different scenarii of static water levels have been applied on the accurate urban topography from LiDAR. Coastal cliffs, located between La Hève and Antifer Capes, showed recurrent gravitational movements. On the period 1985-2008 (23 years), the cliff top shows an average erosion rate of 18 cm/yr. The accumulation of sedimentary instabilities had formed a continuous wedge of 36.7 million m3. The wedge deposits are very variable in size, volume and nature, from north to south. At Le Havre, the impact of the sea-level rise may amplify, in long-term scale, the intensity of these two coastal hazards. However, the SLR impact appears to be low compared to the influence of meteorological factors.
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Contributor : Sylvain Elineau <>
Submitted on : Thursday, January 23, 2014 - 4:51:16 PM
Last modification on : Tuesday, February 5, 2019 - 11:41:20 AM

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  • HAL Id : tel-00935593, version 1

Citation

Sylvain Elineau. Le risque naturel côtier sur la communauté d'agglomération du Havre (Haute-Normandie) : Une évaluation des aléas.. Géophysique [physics.geo-ph]. Université du Havre, 2013. Français. ⟨tel-00935593⟩

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