Geographical Information System (GIS) And Analytical Hierarchy Process Approach For Detecting Of Flood Hazardous Areas In Yewa South, Ogun State

Abstract

Many countries, including developed, developing, and underdeveloped ones, are at risk from floods. Floods have become one of Nigeria's most destructive natural disasters due to several factors which include the effects of climate change, changes in land use, elevation changes., etc. Flood risk is a byproduct of both natural and human activities, necessitating an immediate and improved understanding of its spatial breadth and length. This study attempts to locate and map flood-prone sites in the Yewa (Egbado) South Area of Ogun state. Four (4) criteria: Land use, DEM (Digital Elevation Model), flood direction, and slope, have been chosen for this analysis of flood-prone locations using spatial analysis in the Geographical Information System (GIS) environment. To create a flood hazard map for the area, the Analytical Hierarchy Process (AHP) assigned weight and ranking based on the level of impact the criteria have on flooding; they were used to create a weight overlay comparative map of these criteria. The result shows that part of Ibese and a portion of Ilaro are in the low flood hazard zone, have a 2% risk of flooding, while a larger portion of the area is covered by the medium flood hazard zone (81%), which has a 4% risk of flooding. The high flood zone has a 17% risk of flooding, according to a weight overlay comparative map of these criteria.