Effets de l’ouverture du Canal de Vridi sur les stocks sédimentaires littoraux entre Abidjan et Jacqueville (Côte d’Ivoire)

Ce travail est une contribution a la connaissance des modifications morpho sedimentaires du littoral compris entre Abidjan et Jacqueville. La methode utilisee a cette fin s’appuie sur le traitement, l’analyse de profils topographiques et d’echantillons de sable collectes sur le terrain lors de campagnes successives effectuees entre 1998 et 2008. Cette approche a debouche sur la mise en evidence d’un deficit sedimentaire de -2500 m3 a Port-Bouet et d’un bilan sedimentaire positif de +2300 m3 a Jacqueville. Cet engraissement occasionne une progradation de 13,5 m du trait de cote. L’etude sedimentologique met en evidence des stocks sedimentaires differents sur les deux sites. Un stock constitue principalement de materiels polis et grossiers a Jacqueville qui denote un long transport par l’eau, et un stock constitue essentiellement de materiels subanguleux a anguleux et tres grossiers a Port-Bouet temoignant d’une source pourvoyeuse proche. Cette etude met en evidence les effets des ouvrages de protection du canal portuaire sur la repartition des facies entre Jacqueville et Port-Bouet. Impacts of the construction of Vridi channel on the coastal sediment stocks located between Abidjan and Jacqueville (Cote d’Ivoire) This work is a contribution to the knowledge of sediments and morphology changes of the coast between Abidjan and Jacqueville. The method used for this purpose is based on processing, analysis of topographic profiles and sand sampling collected on the field during successive surveys which were conducted from the year 1998 to 2008. The approach resulted in the identification of a sedimentary deficit of -2500 m3 in Port-Bouet and a positive sediment budget +2300 m3 in Jacqueville. This feeding engrossment causes a coastline progradation of 13.5 m. Sediments study highlights the various sediment stocks on both sites. On one hand, there is a stock mainly composed of coarse and polished material in Jacqueville indicating a long water way carriage, and on the other hand, there is a main stock of sub-angular to angular and very coarse materials in Port-Bouet showing the closeness of the purveying source. This study highlights the effects of protection works realized on the port channel on the distribution of facies between Jacqueville and Port-Bouet. Keywords: Erosion and accretion; Sediment budget; Beach Profile; Port-Bouet; Jacqueville; Cote d’Ivoire.