Storm Events of Nice Bay: A Numerical Modeling of the Interactions Between Wave, Current, and Solid Transport

Abstract

Nice, located in the South–East of France, has constantly been developing on an economical and social level for the last decades. Thus, the urbanization process, implying the development of new infrastructures (Promenade des Anglais, roads and railways), has triggered an important erosion of the beach. Nice’s neighboring rivers, Var and Paillon, were the primary sources regarding the natural supply of beach gravels. But the combination of the airport construction, at the Var river mouth and the structures all along the streams, has stopped the gravel supplies. Those anthropological factors associated to the natural configuration of the beach (steep inner shoreface and narrow zone of concentrated wave breaking) contribute to an important loss of gravel. Studies have demonstrated that the erosion of Nice beaches reaches 15,000 m³/year. In this context, a modeling approach has been started to characterize the solid transport along the Nice shore. The TELEMAC-MASCARET system has been chosen for this study. It is a powerful integrated modeling tool which is composed of different simulation modules such as TOMAWAC and TELEMAC2D. The model created on TOMAWAC has provided results regarding the wave propagation in the bay. The simulations demonstrate the existence of high values of wave heights near the coast due to sub-marine caps. TELEMAC2D coupled with TOMAWAC has been used to simulate the current effects along the shore. During South-East storm events, the center part of the bay is exposed to high velocity values, whereas the west part is less vulnerable to this swell. There are two explanations: the orientation of the bay and the groynes. In order to validate the result of this model, we started a field measurement campaign. We will present its methodology and its first results in this paper.