HYDROLOGICAL MODELLING OF A TWO-OUTLET TROPICAL LAGOON (EBRI LAGOON, IVORY COAST) DURING AN EXCEPTIONAL FLOOD OF THE COMOE RIVER

Since the opening of the Vridi Canal, the natural outlet of the Ebrie lagoon, and that of the Comoe River at Bassam, is no longer permanently open. In effect, the hydrodynamic activity created by the tide has become insufficient to flush and maintain two permanent openings to the sea. In this study, numerical simulation using TELEMAC-2D was used to model the outlet of the Comoe River at Bassam. During these simulations, a decrease in the amount of water was observed at Bassam. Conversely, there was an increase at Vridi. The volume of water bodies and the ability to flush the outlets remains low at the outlet of Bassam. The effect of flushing is very significant and tidal ebb currents are more important.Original Abstract: Depuis l'ouverture du Canal de Vridi, l'exutoire naturel de la lagune Ebrie et celui du Comoe a Bassam, ne peut plus se maintenir ouverte de facon permanente. En effet, l'activite hydrodynamique creee par la maree est devenue des lors insuffisante pour maintenir permanents ces deux debouches en mer. Dans cette etude, l'exutoire du Comoe a Bassam a ete ouvert par simulation numerique de TELEMAC-2D. Durant ces simulations, la baisse de la quantite de masses d'eau s'observe a Bassam. Par contre, on a un accroissement a Vridi. Le volume de masses d'eau et la puissance de chasse restent faibles a l'exutoire de Bassam. L'effet de chasse est tres significatif et les courants de jusant sont plus importants.