Assessment of flood hazard in Owerri West, Imo State, Nigeria using Analytical Hierarchical Process and Index Based Approach
Nnamdi Azikiwe University, Department of Surveying and Geoinformatics, Awka, Anambra State; Nigeria.
Research Article
World Journal of Advanced Research and Reviews, 2021, 12(02), 042–047
Article DOI: 10.30574/wjarr.2021.12.2.0517
Publication history:
Received on 07 September 2021; revised on 12 October 2021; accepted on 14 October 2021
Abstract:
This study aimed at an assessment of flood hazard areas in Owerri Imo State, Nigeria using analytical hierarchical process and index-based approach. The study objectives were to: establish the geophysical factors that contribute to flooding in the study area; classify the established geophysical factors according to the level of flood risk; calculate the reliability index of the classified geophysical factors; determine the flood vulnerable areas using analytical hierarchical process and flood hazard index; and to produce a vulnerability index map defining the extent of flooding vulnerability in the study area. The methodology incorporated in this study involved acquisition of remotely sensed imageries of the study area, pre-processing, Image classification, modelling slope, watershed, Drainage Network, flow accumulation, Soil Classification, classification and standardization, pairwise comparism matrix, normalized weighted Matrix, consistency index check and flood hazard index modelling. The study results revealed that In Owerri West, high flood vulnerability occupied 1.54% with an area coverage of 817.78 hectares, moderate flood vulnerability occupied 28.37% with an area coverage of 15031.98 hectares, low flood vulnerability occupied 24.97% with an area coverage of 13228.25 hectares and no flood vulnerability occupied 1.67% with an area coverage of 882.17 hectares. From the results achieved and the experiences gathered, analytical hierarchy process and flood hazard index-based modelling approach is recommended as it is a robust and efficient tool for mapping flood vulnerability while incorporating robust factors that contribute to flood and having a consistency judgement which judges the reliability of the weights of the factors used during modelling.
Keywords:
Flood Modelling; Remote Sensing; GIS; Owerri West; Pairwise comparison
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