Flood damage assessment of an urban area in Taiwan

In Taiwan, flooding is one of the major natural hazards causing death and millions of dollars of economic losses every year. In order to minimize damage, a detailed and comprehensive flood damage assessment is necessary for both flood control planning and emergency service operations. As such, the objectives of this study were to assess possible flood damages and provide a comprehensive flood risk index for Taichung City in Taiwan. An analytic hierarchy process questionnaire, which included the factors of different land-use types, was designed and answered by 33 experts from governments, industry, and academia in Taiwan. Questionnaire responses were analyzed, and numerical values were allocated for each land-use type. A flood risk index was then produced by combining the potential of inundation and the flood damage scores. Higher flood risk was found along major roads and the main channel of the Fazih River. The methodology used in this study can be applied to most urbanized areas in Taiwan and elsewhere in the world when the required data sets are available.