A GIS Multi-Criteria Evaluation for Flood Risk-Vulnerability Mapping of Ikom Local Government Area, Cross River State

Abstract

Flooding is a significant hydrological hazard in the world and has elicited responses from government and non-government agencies alike due to the damages it portends. This study was formulated on this backdrop, with the objective of designing a flood risk-vulnerability map of Ikom Local Government Area. The types of data employed were majorly secondary. Interviews were also primarily adopted. The multi-criteria assessment meant a systematic combination of independent parameter inputs (distance from river, rainfall intensity, elevation, land use, slope and soil; abbreviated as “DRELSS”) for the analyses. Analytical processes such as buffering, slope generation, interpolation, classification, reclassification and the weighted overlay were used in the ArcMap platform. The methods were all based on existing literature, authors expert understanding and standard analytical procedures. The flood risk-vulnerability map produced from the analysis shows 5 risk zones (very high, high, moderate, low and very low-risk zones). From the analysis, it was discovered that areas close to the rivers were more prone to flooding. A total of 7 communities were within very high-risk zone, which also covers 28 square kilometers (sq km) while 16 communities were in high risk zones within an acreage of 305 sq km, both only making up a significant 16 percent of the total Ikom land area, most of which had built-up human activities. A follow-up ground-truthing exercise bolstered the findings of flood occurrence in the deduced communities. The necessity of a multi-criteria flood risk-vulnerability evaluation in Ikom, like any other area, is thus indispensable as it provides for precaution, preparedness and post-hazard planning. The findings herewith are no doubt vital to the government, urban planners, insurers, emergency services and the likes.