Numerical Investigation of New Alternative Nador Lagoon Inlet Relocation

In this work, new alternative inlet relocation has been investigated using 2D hydrodynamic and transport models to the Nador lagoon (Morocco), a coastal system connected to the sea through a narrow and shallow inlet. The model is based on the finite volume method. It solves the shallow water equations on a spatial domain that represents the whole lagoon basin. The current inlet was artificially opened and an alternative inlet was relocated into a southward position. This work investigates the hydrodynamic patterns and the potential pathways of tracers in Nador lagoon in two distinct configurations: before and after inlet relocation. The hydrodynamic model was successfully calibrated and validated against observed elevations, accurately reproducing the tidal propagation. The inlet relocation increases the magnitude of tidal currents, suggesting a better water circulation. The tracers transport simulations suggest enhanced water exchanges through the lagoon inlet and smaller residence times in the central part of basin with the alternative configuration. Overall, it is concluded that the inlet relocation had a positive contribution towards increasing the water renewal of the whole lagoon, thus decreasing its vulnerability to pollution.