Development of an interdisciplinary coastal erosion vulnerability index for urban communities in the eastern sector of the Togolese coast

Abstract The coasts of West Africa are particularly vulnerable to coastal erosion due to the interaction of physical, climatic, and anthropogenic factors. This study assesses the composite vulnerability of urban communities to coastal erosion along the eastern sector of the Togolese coastline, which spans 39 km and is subdivided into three coastal sections. The methodology combines remote sensing, Geographic Information Systems (GIS), vulnerability scoring, and the Analytic Hierarchy Process (AHP). A coastal erosion vulnerability index (CVI) was calculated based on two complementary sub-indices: the physical vulnerability index (PVI) and the socioeconomic vulnerability index (SVI). The AHP was used to determine the relative importance of the PVI parameters through pairwise comparisons. The results indicate moderate vulnerability of the study area to erosion, with a score of 2.51 on a scale of 1 to 4. Physical and climatic parameters exert a spatially similar influence across the three sections, while differences in scores are primarily related to socioeconomic and human parameters. Section 1, corresponding to a 12 km long stretch located in the municipality of Golfe 6, is identified as the most vulnerable. These results highlight the importance of socioeconomic and human factors in the spatial differentiation of vulnerability to coastal erosion in the study area, and provide a basis for prioritizing adaptation measures and supporting the sustainable management of this coastal sector.