GIS based flood vulnerability modelling using analytical hierarchy process techniques in Jalingo Local Government Area, Taraba State

Abstract

One of the most frequent environmental risks to the communities in Jalingo Local Government Area of Taraba State is flooding. This paper quantified the key variables of flood vulnerability and the spatial map of flood vulnerability was prepared through an Analytical Hierarchy Process (AHP) method based on GIS. Spatial data sets (elevation, slope, rainfall, drainage density, land use, soil type, flow accumulation, and population density, which is a demographic exposure measure) were then obtained and processed. The reclassification of each criterion and the weighting of each criterion were carried out with the pairwise comparison method according to the relative contribution of the criterion to flood susceptibility. The Flood Vulnerability Index (FVI) is developed by the use of Weighted Sum overlay in ArcGIS. The pairwise comparison was used to reclassify each criterion and gives it a weight based on its relative contribution to the susceptibility to floods. The Flood Vulnerability Index (FVI) is created through the use of the Weighted Sum overlay that is conducted in ArcGIS. The results showed that there were significant spatial differences in the flood risk of the study area. Areas with high vulnerability were mostly located in the low built up regions of Jalingo town and in areas of bare soil near river streams. They occur in areas with low slopes and low infiltration rates, which increases the likelihood of water pooling in the event of intense rains. On the other hand, the hilly region which are elevated, steep and thickly vegetated had low flood potential. It is inferred that topography, land cover and human activities are important factors in determining flood vulnerability in Jalingo. The vulnerable map obtained is a valuable tool in land use planning, flood mitigation measures and disaster preparedness within the locality.