Simulation of Pollutants Dispersion in the Bay of Tangier (Morocco)

The study is focused on numerical simulation of the process of coastal pollution by wastewater in the Bay of Tangier in Morocco. The process is governed by flows generated by the tide and the large variations of the discharges from the different Wadis (rivers) flowing into the bay. The simulation requires a number of tests and trials, something that is experimentally expensive and sometimes impossible. Hence the idea was developed of a numerical study aimed at tracking the dispersion of pollutants into the bay and determining the level of degradation of its waters. The simulation was done using the computer CFD FLUENT software, first in 2D modeling to track the spread of pollution on the free surface. The results of this step made it possible to visualize the dispersion mechanism and to gain valuable information on the flow generated by the interaction of discharges and high/low tide movements near the beaches of the bay. This area is naturally the most critical in terms of environment. From the perspective of flows, the results were used to locate stagnant water and turbulent areas. These findings were used to adopt a 3D modeling - where the depth of the bay was taken into account to get closer to reality - subject to certain assumptions and including the influences of salinity and thermal gradients between the surface and the seabed, given the gravity and pressure gradients.