Salt diffusion in calich lagoon: monitoring and modeling for fish farm management

Monitoring and Shallow Water Equations have been applied to the hydrodynamic study of a Lagoon in NW Sardinia. Salinity change in mixed sea and fresh water for fish farm management, have been studied in the cases of both tidal flow alone and mixed tidal flow and fresh water inflow simulation. The damage produced by polluted substances being dumped into the water which is not capable of dealing with them, justifies the development of mathematical means to obtain information. An Alternating Direction Implicit Method with Finite Difference Schemes is used to solve SWE, coupled with the concentration equation. The Eulerian-Lagrangian method to discretize the convective and diffusive terms is adopted to compute the velocity and concentration fields. An analysis of the sensitivity and calibration of the model was carried out. In order to calibrate the hydrodynamic and salt diffusion model, an hydro-weather station for the monitoring of the microclimate and of the tidal and river flow has been installed. The studies of the hydrodynamics of salty water in the Lagoon can be used to forecast planned interventions for fish farm management.