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Answering to the call for proposal ??Vuln?rabilit? des infrastructures vis-?-vis du changement climatique?? (equipment vulnerability to climate change), conducted by the French Ministry of Equipment, EDF R&D signed an agreement with CETMEF (Centre d?Etudes Techniques Maritimes et Fluviales), the G?omer team from the Universit? de Bretagne Occidentale and the Laboratoire de G?ographie Physique (CNRS) to submit a proposition regarding a work programme covering 4 years since 2004, named Discobole (Donn?es pour le dImensionnement des Structures C?ti?res et des Ouvrages de BOrd de mer ? Longue Ech?ance, or in English Data for coastal structure and maritime work long-term design). The project aims at predicting the long-term (100 years) behaviour of some consequences of climate change on maritime and shore climatology, in order to provide a better design and long-term maintenance to waterworks (sea defence, breakwaters, etc.). Numerical simulation allowed us to estimate past trends relative to the spatial distribution of extreme storm surges and wind waves on the French shoreline (Atlantic/English Channel/North Sea). By building plausible meteorological data fields corresponding to the end of the XXIstcentury, we also investigated the effect of climate change on the future evolution of extreme storm surges. Although the methodology is subject to many uncertainties, it points out new quantitative elements regarding the possible future change of hydrodynamical phenomena which are rather difficult to estimate.

At the interface with the ocean, the shore is exposed to the actions of the sea which govern its natural evolution (sometimes imperilling the integrity of the coastline), and affect, during storm events, the safety of human beings and patrimony located in the coastal area (stability of protection works, risk of submersion). In order to evaluate these risks and to prevent them through suitable measures of protection, it is necessary to consider simultaneously the effects of wind waves, marine currents, tides and storm surges. For several years, the LNHE has been developing a numerical modelling system (TELEMAC), based on various coupled modules, which allows to hindcast, and potentially to forecast, the combined effects due to the astronomical ride and to the atmospherical forcing (storm surges and waves). This modelling system has been successfully applied at continental scales (Atlantic coastlines of France, English Channel, North Sea), as well as regional scales (Dover Straits, Gironde estuary) for various extreme meteorological conditions.