A GIS Based Flood Vulnerability Assessment of Abia State, Nigeria.

Abstract

This paper assessed flood vulnerability in Abia State of Nigeria using Geographic Information System (GIS) techniques. The specific objectives included the creation of GIS data base; operationalization and modeling of identified flood vulnerability components; and, the generation of composite flood vulnerability map of the study area. In the study, vulnerability was mapped as a function of exposure, sensitivity and adaptive capacity, using GIS technology. Constituents of each of the three components of vulnerability were identified, weighted and combined using the single output map algebra of the spatial analyst tools extension in Arc map 9.2 environments to create
three surfaces which were then combined in the same way to generate the final flood vulnerability layer. The final map was then zoned into high, moderate and low vulnerability classes. The results indicated that the areas of high vulnerability to flood occupied 37.33% of the study area and were found in the north and south central parts of the state. The moderate vulnerability areas covered 35.75% and were found in the central, southern and north east areas; while areas with low vulnerability to flood covered 26.94% of the study area and were found around the south and south central parts. It was recommended from the study that a comprehensive plan involving multihazard risk assessment is required for mapping out vulnerability hot spot areas. This will help authorities and stakeholders to steer development towards sustainability.