In different regions of Nigeria, floods have increased dramatically, affecting millions of people and inflicting huge economic damage. Flood disasters can be attributed to the unnecessary risks people take when they encroach on floodplains. Flood hazard maps are important to integrate geospatial and temporal data in the same computational environment that allows risk assessment, modeling and decision support. The aim of this study is based on flood vulnerability assessment along Ikpoba River in Benin City using GIS technology for mapping vulnerable areas within the study area. The imagery was geo-referenced in ARCGIS 10.0 and the necessary layers were created. The study thus involves the digitizing of different layers such as road, building and river to produce a vulnerability map to ascertain buildings that are located within the flood risk zones in lines with the stipulated setback. Spatial database was created and analyses were performed in assessing buildings within the risk zones. Analysis like buffering, query and classification were carried out to achieve the objectives. Some buildings were found within vulnerability zones according to the setback. Results were grouped into four (4) categories based on the proximity of risk when flooding occurs. Category 1 was classified as high vulnerability zone and has 17 buildings, Category 2 was classified as moderate vulnerability zone with 73 buildings, Category 3 was classified has low vulnerability zone with 124 buildings and Category 4 was classified has non vulnerability zone with buildings amounting to 1885. This study emphasizes the urgent need to put in place measures to facilitate effective management of the anticipated floods to prevent the re-occurrence of the damage and losses of lives as noted by the study. The study therefore recommended that Government must enforce compliance with physical planning and development regulations within Benin Metropolis and there should be immediate stoppage of all kinds of development in all flood prone areas in the 8 LGAs in Benin region.
Keywords: GIS, Vulnerability, Flood, Effective Management, and Drainage