Fluvial Dynamics of the Sassandra River in the Departments of Facobly and Kouibly (Western-Côte d’Ivoire) During the Period 2016–2024

This study aims to characterize the morphology of the Sassandra River using satellite imagery acquired between 2016 and 2024 in order to support population safety in the context of potential flood hazards. The specific objectives are to evaluate riverbed evolution, analyze morphological changes, and identify the factors driving these transformations. Satellite images were processed using cartographic and geospatial tools, particularly QGIS 3.36, to assess river dynamics and quantify areas affected by erosion and sediment deposition. A diachronic analysis was conducted using the Normalized Difference Water Index (NDWI) to identify wetlands and monitor spatial changes in the river channel. Two four-year periods, 2016-2020 and 2020-2024, were examined to evaluate patterns of river regression and transgression. The results reveal that the Sassandra River exhibits a meandering channel pattern associated with an almost flat slope. Between 2016 and 2020, sediment deposition was the dominant process, accounting for approximately 82% of the observed changes, while erosion represented 18%. In contrast, the 2020-2024 period showed an increase in erosional activity, with erosion reaching 43% and sediment deposition decreasing to 57%. These findings demonstrate the continuous evolution of the river channel and highlight the significant influence of climate variability on fluvial processes. The observed morphological changes may increase the vulnerability of surrounding areas to natural hazards, particularly flooding. This study provides valuable information for river management, environmental monitoring, and flood risk mitigation in the Sassandra River basin.