Coastal Zones

Biography

Biography: Degbe Lossi Georges Epiphane

Abstract

This work aims to study morphology and to follow the evolution of the coastline of the Beninese littoral for better apprehending the phenomenon of coastal erosion. To conduct this study, it was used the direct method based on the mesures of topographical surveys taken of 2011 to 2014 in sensitive areas of the Beninese littoral. The volume of eroded or fattened sediments is obtained from eroded or fattened surfaces calculated by the method of trapezoid. The obtained results bring us to observer vertical and horizontal movements profiles which enable us to distinguish periods of dominant erosion from May to September and from the periods of dominant accumulation from November to April. For the first periods, the profiles tend to pass from the convex form to the concave form, while with the course the second period, they tend to pass from the concave form to the convex form. The coastal sectors most threatened by the retreat of the coastline (erosion) are located East of the split (east of Cotonou) with a mean velocity approximately -9 ± 0.03 m/year at Donatin and approximately -30±0.03 m/year at the East at the level of the bridge toll, the sectors of Djondji with -2±0.03 m/year and the sectors between Hillacondji and Agoué with -5±0.03 m/year. The Sectors of coast which are in dynamic balance or accretion are the sector of coast located at the west of the port of Cotonou with a speed of +4±0.03 m/year and the sector between Ayiguénou and Grand-Popo which is stable. The coastline of the Beninese littoral knows a seasonal evolution.