Finite volume modelling of a stratified flow with the presence of submerged weirs

The saltwater intrusion in the estuary of the Adige River has been investigated by a two-dimensional finite volume shock-capturing model. Owing to the relative small tide range characterizing the river mouth, a sharply stratified salt wedge tends to form during low discharge periods (e.g. in summer). Suitable hydraulic relations have been introduced to model the action of a submerged barrage, located close to the estuary mouth and built to hinder seawater intrusion. Field measurements of salinity profiles have been used to calibrate the model. The numerical results suggest that, as a consequence of increased water withdrawal that occurred in the last years, the barrage does not prevent efficiently the intrusion of the salt wedge any more.