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

Abstract

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.