Evolution of Surge Levels Inside Harbour Basins: the Case of Le Havre Harbour

Résumé En

Within the Technical Commission for the Study and the Evaluation of Maritime Submersions in the Seine Estuary (CTeeSMES), whose aim is to improve the collective knowledge on physical processes linked to maritime surge levels, a numerical model of the Seine estuary based on TELEMAC2D has been used to study the evolution of surge levels from the ocean to the harbour area of Le Havre and, in particular, evaluate the amplification of the global signal and the apparition of seiches inside René Coty''s basin. The bathymetry of the model was partially provided by Le Havre and Rouen Harbours for the north-east part of the model. For the rest of the area, EMODNET was used. The numerical model was calibrated on Johanna (March 2008) and Xynthia (February 2010) storm events. The global signal (tide + surge levels) was calibrated using measurements available on seven outputs of the Seine Estuary and provided by ports of Le Havre and Rouen to optimize the friction coefficient and the coefficient for wind influence. Winds and pressure fields came from CFSR data. Once the numerical model of the Seine Bay had been calibrated, it has been possible to draw the evolution of surge levels from the ocean to Le Havre (quai Meunier) and then to compare the signal obtained inside René Coty harbour basin. As shown by measurements, numerical results stress out the apparition of an oscillating signal which is added to the signal at the entry of the Harbour. The process of amplification of seiche inside the port near the René Coty harbour basin is still underestimated by the model and further investigations must be realised.