Two-Dimensional Numerical Modeling of Morphodynamic Evolution in Bouregreg Estuary (Morocco)

Abstract

The Bouregreg Valley, located on the Atlantic coast of Morocco, has been subject to several anthropogenic and natural impacts that disturb the proper functioning of the estuary’s ecosystem. Important dredging operations influenced by both tides and freshwater inflows have created a significant variation of the estuary’s morphology characterized by a sand bar developed at the mouth. The main objective of this study is to investigate the Morphodynamic processes of the estuary and in particular the impact of dredging operations using a two-dimensional horizontal numerical (2DH) modeling approach based on the shallow water equations. Several numerical tests have been carried out to calibrate the model and to investigate the hydrodynamic and morphological aspects of the estuary. For this technical solution, the modeling simulations show that in addition to the quantities of sand that will be dredged initially, the maintenance of the channel will facilitate a better water circulation between the Bouregreg valley and the Atlantic Ocean and improve the stability of the civil engineering structures and the neighboring monuments. In addition, this water circulation will guide the river flow in the ebb phase of the tide. The model results show a reduction of about 30% in the impact of erosion, observed before the digging of the canal;