The aim of this paper is to give an example of the application of the continuous monitoring of environmental data and numerical modeling in resolving the specific problem of coastal erosion. The example is part of a project in progress aimed at monitoring the coastline of the Lignano and Bibione beaches. Although these areas in the northern Adriatic Sea are not protected areas, they constitute the major natural resource of the local communities, and as such there is strong economic, social and political pressure to conserve them. Since 2001, a continuous monitoring of wave motion (DWR buoy) and of meteo-marine variables (MAMBO buoy) has been carried out in the Gulf of Trieste, to the south of the two beaches. This allows the application of a numerical model to obtain necessary information for the study of coastal erosion in the area. The evaluation of sediment transport using morphological data to compare several possible solutions aimed at reducing the phenomenon is currently being attempted. In this paper, some examples are given on the tidal numerical simulation in the Trieste Gulf, validated with the measured data and on the modeling of wave propagation in the same area. Since both, monitoring and the implementation of the models are in progress, the paper shows preliminary results.