Telemac 2D Modeling of Pollutant Transport in the Medjerda River: Impact of Tamarix Vegetation, Bousselem, Tunisia

The aim of this study is to evaluate the impact of pollutant discharges from Bousselem WWTP in the Medjerda River (Tunisia). We chose to model the transport of a passive pollutant from the Bousselem WWTP using Telemac 2D model. The hydrodynamic model calibration was based on identifying the roughness coefficient derived from existing vegetation, mainly from the Tamarix type. Three scenarios of hydrocarbon dispersion representing potential accidents, with concentrations of 0.25, 10, and 50 kg/m3, were simulated. Three successive downstream sections were chosen to track concentration variability in space and over time. The final concentrations recorded (6 km from discharge point) are 500 μg/l, 12 μg/l, and 2.4 μg/l for scenarios of 50 kg/m3, 1 kg/m3, and 0.25 kg/m3, respectively. These values significantly exceed the international norm for drinking water, set at 1 μg/l, and so causing problems for drinking use. The obtained results serve to ensure environmental safety for hydraulic resources.