GIS Based Assessment of Flood Risk and Vulnerability of Communities in the Benue Floodplains, Adamawa State, Nigeria

The focus of this study is to assess the 2012 floods incidence that swept the communities along the coastal areas of Nigeria as well as those along the valleys of the major rivers in the country. It was observed in the study that the floods at the valleys and downstream of River Benue were seriously devastating following the release of water from the Lagdo dam that was located at the upstream of River Benue in the Republic of Cameroon. The method of data collection employed in this study is the application of Geo-information techniques which involves the use of Global Positioning System (GPS) to capture the coordinates of 120 communities which cut across the seven LGAs located along the valleys of River Benue in Adamawa State. These communities were linked to a generated digital map of River Benue valley using ArcGIS software to assess each of the communities for flood vulnerability. Vulnerability was classified into four: highly vulnerable, vulnerable, marginally vulnerable and not vulnerable. The major findings revealed that all the 120 communities in the area were described as vulnerable to flood, that is, they are either highly vulnerable, vulnerable or marginally vulnerable. 29 communities representing 32.5% were located on highly vulnerable areas, 35 communities (representing 29.17%) were found to be located within the Benue Basin but outside the buffer zones which are classified as vulnerable areas, while the remaining 46 communities (38.33%) were located on the plains which are classified as marginally vulnerable areas. Escape routes and good sites for refugee camps during floods were also identified while database creation and analysis for flood vulnerability were also developed. It is therefore, recommended that all the settlements that were highly vulnerable be relocated to higher grounds to prevent future occurrence, while the communities that are located within the Benue Basin but outside the buffer zones should employ the use of GIS tool for effective planning and proper early warning systems.