Application of an index-based approach in geospatial techniques for the mapping of flood hazard areas: A case of cape coast metropolis in ghana

Abstract

Floods remain one of the disasters that destroy properties, livelihoods, and in extreme situations, take lives. As a way of prevention, geospatial applications have been employed in many cities to map flood zones and predict floods. For a country such as Ghana, floods have been ranked as the second fatal disaster after epidemics leading to several kinds of research to resolve them. To date, the Cape Coast Metropolis (CCM) has received little attention in terms of research, though flood cases in the area continue to escalate. This study, therefore, examines the use of geospatial techniques as tools in addressing flood problems in the CCM of Ghana. From a Digital Elevation Model, hydrologic variables were generated using the ArcGIS software (Esri, Redlands, CA, USA). The soil drainage classification for the study was generated from a downloaded African Soil Grid Drainage map, while other important factors that influenced flooding in the CCM were obtained from Landsat 8 imagery. Over 21% of the CCM was classified as high flood hazard zones with areas around the river Kakum estuary being flood hotspots. It is, therefore, recommended that the CCM Assembly fund dredging of streams/rivers and promote afforestation along river banks to reduce the risk of flooding within the metropolis.