Modélisation et observation de submersion de dunes en Languedoc-Roussillon

Abstract

The « coastal squeeze », which basically results in less beach area and more concrete, fortunately does not yet concern the entire Mediterranean coast. It is thus important, while there are still coastal barrier islands, to study and understand the overwash phenomenon, in order to help anticipate the hydrodynamic and sedimentary processes that drive the responses of dunes to important meteorological events. This article first defines and describes the overwash processes that affect coastal dune behaviour, and then presents the analysis carried out by the EID Mediterranee on the beach of Villeneuve les Maguelone, located between Sete and Montpellier in the region of Languedoc Roussillon, France. This analysis allowed us to construct a schema of the responses of the barrier island of Villeneuve les Maguelonne to the meteorological conditions present during the storms of December 3rd and 4th, 2003 and February 21st, 2004. A hydrodynamic model that integrates the radiation stresses (Berkhoff equations) into the Saint-Venant equations was then attempted with the help of the ARTEMIS and TELEMAC calculation codes, in order to characterize the hydrodynamic properties of the system. Finally, a critique of the results is offered and suggestions for improvement are proposed.