Application of COHERENS model for hydrodynamic investigation of Sacca di Goro coastal lagoon (Italian Adriatic Sea shore)

The work presents results of numerical investigations, based on COHERENS model, for Sacca di Goro coastal lagoon. COHERENS is a 3D hydrodynamic finite-difference multi-purpose model for coastal and shelf seas, which could be coupled to biological, resuspension and contaminant transport models and resolves mesoscale to seasonal scale processes. At this stage, the effort is focused mainly on the physical aspects of the modelling as an important background for the future investigation of nutrient dynamics, biogeochemical processes and contaminant transport in Sacca di Goro. The model is forced by considering tidal surface elevation at open sea boundary, river discharges, surface stress as a function of wind speed, air temperature, relative humidity and cloud coverage, bottom roughness and heat flux through sea surface. The numerical model was tested and verified against short observations for water surface elevation and currents during high tide events and also using complete 1 year series of salinity and temperature records. After the calibration phase, surface elevation and current patterns formed under variety of tide and wind forcing have been studied. The travelling times of coming/outgoing Adriatic Sea tides and residence times for the different parts of lagoon have been also calculated. Finally, the differences in temperature and salinity fields calculated before and after an intervention to improve lagoon–Adriatic Sea exchange have been analysed.