Geospatial Assessment of Flood Risk in Borgu Local Government Area, Niger State, Nigeria

Session: Remote Sensing, Visualization, and Spatial Data Applications for the Great Lakes (4)

Obot Ibanga, University of Benin, [email protected]
Friday Idehen, Igbinedion University, [email protected]

Abstract

Introduction: In Nigeria, floods are the most common disaster and the cost of damage to human lives, farmlands, livestock and infrastructure are on the rise. The study utilized geospatial techniques (GT) to assess flood risk in Borgu Local Government Area (BLGA), Niger State, Nigeria. Methods: Flood risk (FR) was modeled as a function of six flood hazards (FHs) and two socio-ecological (flood vulnerability - FV) indicators using raster calculator in ArcGIS environment. Spatial extent of the FR, FH and FV layers were computed as the product of pixel resolution and count while Natural Breaks (Jenks) classification framework was utilized to re-classify the layers. Results: The result showed that elevation, soil water index of wettest quarter, normalized difference vegetation index, rainfall of wettest quarter, runoff of wettest quarter and distance from rivers contributed 44.7%, 33.6%, 22.5%, 20.9%, 17.5% and 13.3% to the FH respectively. About 92.4%, 0.7% and 90.3% of BLGA fell under High flood hazard, vulnerability and risk zones respectively while 3.1%, 23.8% and 4.9% were Moderate. Also, 4.5%, 75.5% and 4.8% were classified as Low flood hazard, vulnerability and risk zones respectively. Conclusion: GT proved a viable decision-support tool in flood risk mitigation with easy visualization through maps.