Hydrodynamic modeling of a coastal lagoon: The Cabras lagoon in Sardinia, Italy

A framework of numerical models has been developed and applied to the coastal lagoon of Cabras in Sardinia, Italy. These models consist of a two-dimensional hydrodynamic model, a radiational transfer module of heat at the water surface and a transport diffusion model. In the first part of the research the hydrodynamic circulation of the lagoon has been simulated taking in account different forces such as tide, wind and rivers. A finite element hydrodynamic model has been applied to the lagoon, describing its geometry and bathymetry with about 6000 triangular elements. The time integration is handled by a semi-implicit algorithm. With the same model the evolution of the salinity in the lagoon has then been investigated. Moreover, a thermal radiative model has been implemented that can describe the temporal variation of the temperature in the lagoon. An ad hoc field campaign between November 2000 and October 2001 has been set-up in order to gather temperature and salinity data to compare with the results of these models. A special scenario has been also simulated in which the Scolmatore channel, which connects the lagoon to the sea and that is closed by a dam, has been opened, allowing the tide to enter more directly into the lagoon and enhance the water exchange.