MECHANISM OF SPATIO-TEMPORAL EVOLUTION OF COASTAL SANDY BODIES IN A MOUTH: CASE OF THE COMOE RIVER ESTUARY IN GRAND-BASSAM, BAS COTE D'IVOIRE WEST AFRICA

Abstract

The mouth of the Comoé River, a transition area between the marine, lagoon and river environments, makes it a dynamic environment. It is this dynamism and the spatio-temporal distribution of sandy bodies in this particular coastal area that was the subject of this work.  It appears from this study carried out with the help of library data (physical and numerical) and softwares that the dynamism of the sandy bodies of the mouth has not been uniform in time. Indeed, before the opening of the Vridi canal, the high-water flow at the outlet of the grau prevented the accumulation of coarse particles. But the digging of the port structure will reduce the water flow in the Grand-Bassam estuary, which will cause the accumulation of sandy bodies at the mouth. The successive series of clogging and opening of the mouth will not be without consequence on the dynamism of the sandy bodies in this area. Indeed, before the opening, the granulometry of the deposits is much thinner and essentially made up of silt and thin sands, but after the opening, the tidal current, which becomes more important, will carry the silt and thin sands out to sea and leave much coarser sandy facies exposed.

In general, this study has shown that sand movements are dominated by a sandy increase in erosion in the vicinity of the mouth, while the opposite is observed in more distant environments.