Évaluation des dynamiques estuariennes en Casamance : cas des îles de Karabane et Diogué et de la pointe de Gnikine

Abstract

The coastline of Casamance, in the south of Senegal, is marked by a generalized retreat of the coastline, except for some prograding areas in its northern part. The islands of Karabane, Diogué and the Gnikine point are very vulnerable (low topography of about 2 m and sandy beach) and are part of this regressive dynamic. This contribution uses a cartographic and statistical approach to study the morphosedimentary dynamics and hydrodynamic factors around the Casamance River estuary. The results show that the sites studied have undergone phases of erosion and accretion. Despite the accretion rates observed in some segments, the recession remains globalized in the whole measured area. On the island of Karabane, the balance remains globally negative with a recession of 0.60 m/year on average, while on the shores of the island of Diogué and at the tip of Gnikine, the recession is respectively 5.85 m/year and 3.30 m/year due to increased exposure to the dynamics of the mouth where the hydrodynamics is more intense.

Keywords

• Hydrodynamic
• Cinematics
• Coastal erosion
• Senegal