Multicriteria index and analytical hierarchy process on flood risk assessment: Application in Niger state, Nigeria

Abstract

Assessment of flood risks, especially extreme floods, is required for any location that is faced with recurrent flooding events for proper implementation of proactive measures. Therefore, this study presents a multi-criteria index-Analytic Hierarchic Process (AHP) approach to evaluate regional flood risks employing multiple flood causative factors by determining a Flood Risk Index (FRI) using a GIS-based spatial analysis. The developed framework utilized topographical, hydrological and vegetal factors to delineate the risks associated with various regions. The relative importance of each factor in determining flood vulnerability, as well as the severity of flood is associated with the weightage of such factors based on AHP. The framework has been applied to Niger State, situated within the north-central part Nigeria, which has been experiencing recurrent annual flooding events. The overall result revealed some vital details on the relative importance of each factors in inducing regional floods. Furthermore, the accuracy assessment conducted using regional flood inventory confirmed the reliability and validity of the developed Multicriteria Index and Analytical Hierarchy Process on Flood Risk Assessment (Mi-AFRA).