Derivation of a GIS-Based Flood Hazard Map in Peri-Urban Areas of Greater Lomé, Togo (West Africa)

Abstract

In Togo, and especially in the peri-urban areas of Greater Lomé, flood hazards and their effects on communities and ecosystems have increased in recent years due to global changes. This is predominantly due to increasing urbanization and the changing climate. This study explores the application of remote sensing, geographic information system (GIS) and analytical hierarchy processes (AHP) for flood hazard mapping in Greater Lomé. Maps of seven (7) drivers of flood hazards, namely flow accumulation, rainfall intensity, geology and soil, land use, slope, elevation and distance from the drainage network, were prepared by integrating remote sensing data into a GIS environment. The weight of each factor was estimated via the AHP method and used in the estimation of the flood hazard index (FHI). The results show that there is a high or very high susceptibility of flooding in 53.4% of the Greater Lomé suburbs, while there is a moderate to low susceptibility of flooding in about 46.59% of it, and 0.01% of the study area. The generated map is a useful tool for decision-makers and practitioners in charge of flood risk and disaster management when developing plans to reduce the risk of both current and future floods in the study area.