Geomorphological Changes at the Estuary of Comoe River (Grand-Bassam, South Eastern Côte d’Ivoire) Due to Suspended Solids Transport

Abstract

The estuary of Comoe River in Grand-Bassam is facing to a hydrosedimentary dynamics spectacular than the others estuaries of Côte d’Ivoire. The sediments deposits produce a sandbank which breaks the natural contact between Comoe River and Atlantic Ocean. This increases the concentration of solid matters in suspension, the confinement and the invasion of the estuarian environment by aquatic vegetables. This study aims to know the spatio-temporal dynamics of physicochemical parameters, from the suspended solid loads of Comoe River estuary. The water samplings have been made over two seasonal cycles between 2005 and 2007 to quantify suspended solid transport. The solid discharges in suspension in the estuary are estimated about 72000 tons of sediments per year. The estuary waters are moderately mineralised and present some pH values near the neutrality. Mineralization is influenced by seasons. The estuary is turbid and slightly oxygenated over every season. The dissolved oxygen averages are 0.5 and 1.6 mg.L-1 respectively during the rainy and the dry seasons Comoe River estuary has relatively low salinities (with an average of 1 mg.L-1).