DETERMINATION DES PERIMETRES DE PROTECTION DE LA LAGUNE AGHIEN PAR LE CALCUL DU TEMPS DE TRANSFERT DE L’EAU JUSQU'A LA LAGUNE

Abstract

The operating capacity of the Abidjan ply became insufficient. The deficit in drinking water resources in the District of Abidjan remains the major concern of the decision maker. The Aghien lagoon stands as one of the most interesting alternatives. However, studies show the levels of pollutions of this resource without lighting on the causes and sources of these pollutions. The present study extends over the entire catchment of the lagoon reveals the presence of urban areas and agricultural activity areas in the catchment. This raises real concerns for the Ivorian authorities. This study aims to make a hydrological analysis from the DEM of the supply catchment for the delineation of protected areas of the lagoon. The approach has shown a connection between the lagoon and wastewater discharges from urban areas. Transfer times of domestic wastewater in the lagoon are between 25.9 hours (1 day) and 45.54 hours (2 days). Three protective perimeters (immediate, near and far) of this lagoon have been proposed. The implementation of these protection areas involves better farming and domestic practices within catchment to fight against erosion and pollution for the preservation of this resource.