Flood Risk Assessment in Uhunmwonde Local Government Area (ULGA), Edo State, Nigeria., Nigeria

Session: Remote Sensing, Visualization, and Spatial Data Applications for the Great Lakes (1)

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

Abstract

Introduction: Flooding is one of the environmental problems that affected 35 states and 380 Local Government Area (LGAs) in Nigeria  in 2018.This paper mapped flood risk zones (FRZ), evaluated impacts of flooding and coping measures in ULGA. Method: Flood risk (FR) was mapped using hazards and vulnerability and implemented in ArcGIS software using multi-criteria analysis – based analytic hierarchy process (AHP) by incorporating 6 environmental and 2 socio-economic factors. Elevation, soil water index of wettest quarter, normalized difference vegetation index, distance from rivers, rainfall and runoff of wettest quarter constituted the hazard component while population density and area of agricultural land use was the vulnerability layer. Structured questionnaires were administered to 280 respondents randomly selected from 20 high FRZ and data analyzed in SPSS 22. Result: The flood risk map indicated that zones with high, moderate and low FR covered 45%, 36% and 19% of ULGA respectively. About 72%, 70% and 64%, of houses, farmland/crops and water supply/sanitation were destroyed by 2018 flooding. Coping measures include relocation (54%), drainage construction (52%), used sand bags/mould (49%) and raising of floor of their houses (36%). Conclusion: Spatially explicit information through maps are priceless in risk assessment, policy and well-targeted programs intervention.