Identification of Areas Influencing Vulnerability to Sedimentation in the Bacon Reservoir in South-eastern Côte d'Ivoire: A Mapping Approach

Abstract

Soil erosion and sediment transport are causes of reservoir storage capacity loss. This study addresses the issue of access to clean water in the Akoupé Bacon area of Côte d'Ivoire. The watershed of the study area accommodates a reservoir constructed to provide water supply to the populations of Bacon, Akoupé, and soon the municipality of Affery. In recent years, the water reservoir has been experiencing eutrophication and sedimentation phenomena.These problems lead to a reduction in the water reservoir's storage capacity. The objective of this study is to map the vulnerability of the Akoupé-Bacon reservoir to sedimentation. The methodological approach is based on the development of a Geographic Information System (GIS) that integrates multi-source data (soil erodibility, rainfall erosivity, topographic slope, land use, and slope exposure) to establish a map of vulnerability to water erosion using an additive combination. Three vulnerability classes were distinguished: highly vulnerable areas (55.92%), moderately vulnerable areas (43.18%), and areas with low vulnerability, which are almost non-existent in the region (0.89%).Thus, the moderately and highly vulnerable areas represent 99.1% of the region's total area. This map of reservoir sensitivity to sedimentation demonstrates that the Akoupé Bacon region is highly exposed to soil losses and, consequently, significant sedimentation in the reservoir. This study used GIS technology incorporating multi-source data (soil erodibility, rainfall erosivity, topographic slope, land use, and slope aspect) to map zones influencing sedimentation vulnerability in the Akoupé Bacon water reservoir.