Flood hazards and risk mapping using geospatial technologies in Jimma City, southwestern Ethiopia

Cities in Ethiopia are suffering from unprecedented floods due to climate change and other anthropogenic activities. Failure to include land use planning and poorly designed urban drainage system aggravates the problem of urban flood. The integration of geographic information system, and multi-criteria evaluation (MCE) technique were used for flood hazards and risk mapping. Five factors namely slope, elevation, drainage density, land use land cover, and soil data were used for flood hazards and risk mapping. Agrowing urban population increases the risk of flood victims during the rainy season. Results revealed that about 25.16 and 24.38% of the study area is categorized under very high and high flood hazards, respectively. The topographic nature of the study area increases flood risk and hazards. The increaseing number of people living in the city has led to the conversion of previously occupied green lands into residential areas aggravates flood hazards and risk. Flood mitigation measures such as better land use planning, public awareness creation on flood hazards and risks, delineation of flood risk areas during the rainy seasons, increasing greenery, strengthening river side development, and watershed management in the catchment are urgently required. The findings of this study can provide a theoretical background for flood hazards risk mitigation and prevention.