Testing Alternatives for Salt Wedge Management in an Estuary with the Use of Monitoring and a Mathematical Model

The intrusion of salt wedge in rivers is a natural phenomenon, which occurs in many estuaries. Saline
water tends to propagate upstream from the river mouth, due to the limited freshwater and the tidal
and density currents developed, resulting in deterioration of water quality in the lower river reach.
Several methods to control the salt wedge have been employed, including the construction of inflatable
dams or gates. A promising method of control is the use of an air curtain. In this study, a two-dimensional,
laterally averaged numerical model has been developed to describe salt wedge intrusion. This
model provided necessary hydraulic parameters, which were used in air curtain design theory to evaluate
the application of the air curtain method in a particular estuary system. The application takes place
in the estuary of Strymon River in Northern Greece, where the limited discharge of freshwater, mainly
caused by the construction of Kerkini dam, results in the creation and upstream intrusion of a salt
wedge in the summertime, affecting water quality and making water unsuitable for irrigation uses.