A better understanding and prediction of the dynamic processes that govern the coastal zone is the topic of the current paper; in particular, a deep investigation of the coastal processes that affect the shoreline dynamic and flood inundation risk is carried out at the Annunziata river mouth area (Italy). The Annunziata River is situated in the Northern part of Reggio Calabria city; it is, at the same time, a source of danger and an important environmental and hydrological resource for Reggio Calabria, since on the right side there is the city port and on the left side there is the public beach. The protection and management of coastal areas should be supported by a deep knowledge of the interaction between water motion and seabed topography, which affects the natural response of coastal systems to changes in external conditions and to human interferences. This work tries to analyze the coastal morphology through the use of some recent models based on spectral theory.