Water Circulation and Transport Timescales in the Gulf of Oristano

In this work, water circulation in the Gulf of Oristano was investigated using a 2D hydrodynamic model. The model is based on the finite-element method. This solves the shallow-water equations on a spatial domain representing the Gulf of Oristano and the surrounding coastal sea. The hydrodynamic features of the gulf were investigated when the basin is influenced by different wind regimes. In order to evaluate the renewal capacity of the basin, the residence and the transit times were computed for each scenario. The study reveals that the gulf is characterized by circulation patterns promoting strong trapping phenomena. The results obtained are partially confirmed by the heavy-metal distribution in the sediments. In particular, the southern part of the basin is characterized by the presence of high heavy-metal concentrations in the bottom sediment, in the same areas where model results reveal a strong trapping capacity. This study can be considered as a first attempt to investigate the wind-driven water circulation in the Gulf of Oristano, and the results obtained can help in planning hydrological campaigns in the basin.