Flood is one of the highly pronounced ruinous naturally occurring environmental hazards in which human lives and properties are gravely endangered. This study assessed areas prone to flood in Ibadan City, Nigeria. The study applied two multi-criteria analysis approach—Analytical Hierarchy Process (AHP) and the Fuzzy Analytical Hierarchy Process (FAHP) with the aid of GIS. Ten geomorphological physical characteristics agreed upon by experts as the major factors influencing the susceptibility of an area to floods formed the criteria maps used in this study. The natural breaks and geometrical interval clustering techniques were utilised to group the final flood-prone area maps into five categories—very low, low, moderate, high, and very high. The result indicated that over 50% of the study area either have low or moderate susceptibility to flooding. The clustering techniques showed some slight differences in the flood classifications where natural breaks consistently grouped more areas into the “very high” category and relatively fewer areas to “very low” category in comparison to the geometrical interval technique. Overall, at least 451 km² (about 15% of Ibadan) is highly or very highly prone to floods, and these areas are mainly concentrated in the urban and semi-urban regions of the study area. The findings and maps developed in this study would adequately serve as a planning guide for the policymakers on urban development and flood risk management to achieve sustainable development and management.

中文翻译：

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使用基于 GIS 的层次分析框架为尼日利亚伊巴丹市绘制洪水易发区地图

洪水是一种非常明显的破坏性自然发生的环境危害，其中人类生命和财产受到严重威胁。这项研究评估了尼日利亚伊巴丹市容易发生洪水的地区。该研究应用了两种多准则分析方法——层次分析法（AHP）和借助 GIS 的模糊层次分析法（FAHP）。专家一致认为的十个地貌物理特征是影响一个地区对洪水的敏感性的主要因素，形成了本研究中使用的标准图。利用自然断裂和几何间隔聚类技术将最终的洪水易发区域地图分为五类——极低、低、中、高和非常高。结果表明，超过 50% 的研究区域对洪水的敏感性较低或中等。聚类技术在洪水分类中显示出一些细微的差异，与几何间隔技术相比，自然断裂始终将更多区域归为“非常高”类别，而将相对较少的区域归为“非常低”类别。总体而言，至少 451 公里²（伊巴丹约15%）高度或非常容易发生洪水，这些地区主要集中在研究区的城市和半城市地区。本研究开发的结果和地图将充分作为城市发展和洪水风险管理决策者的规划指南，以实现可持续发展和管理。