Flood Risk Assessment in Urban Areas of Southern Taiwan

Wen-Cheng Liu,Tien-Hsiang Hsieh,Hong-Ming Liu

doi:10.3390/su13063180

Abstract

A flood risk assessment of urban areas in Kaohsiung city along the Dianbao River was performed based on flood hazards and social vulnerability. In terms of hazard analysis, a rainfall-runoff model (HEC-HMS) was adopted to simulate discharges in the watershed, and the simulated discharges were utilized as inputs for the inundation model (FLO-2D). Comparisons between the observed and simulated discharges at the Wulilin Bridge flow station during Typhoon Kongrey (2013) and Typhoon Megi (2016) were used for the HEC-HMS model calibration and validation, respectively. The observed water levels at the Changrun Bridge station during Typhoon Kongrey and Typhoon Megi were utilized for the FLO-2D model calibration and validation, respectively. The results indicated that the simulated discharges and water levels reasonably reproduced the observations. The validated model was then applied to predict the inundation depths and extents under 50-, 100-, and 200-year rainfall return periods to form hazard maps. For social vulnerability, the fuzzy Delphi method and the analytic hierarchy process were employed to select the main factors affecting social vulnerability and to yield the weight of each social vulnerability factor. Subsequently, a social vulnerability map was built. A risk map was developed that compiled both flood hazards and social vulnerability levels. Based on the risk map, flood mitigation strategies with structural and nonstructural measures were proposed for consideration by decision-makers.

Highlights

Introduction and George DBathrellosIn recent years, the economy has developed rapidly in various parts of the world, and countries have used many fuels, such as oil and coal, that cause holes in the ozone layer and produce a large amount of greenhouse gases such as carbon dioxide and methane, resulting in a continuous rise in temperature
Among the types of natural disasters that occurred in 2018, flood-related disasters accounted for 74% of all disasters; floods made up 39% of the total number of disasters, storms made up 30%, and slope disasters made up 5%
Flood-related disasters in urban areas are subject to several factors, such as urban development, construction of transportation facilities, extreme weather and climate change, development, construction of transportation facilities, extreme weather and climate change, and anthropogenic changes that alter vulnerability, hazards, and risks [59]

Summary

Introduction

Introduction and George DBathrellosIn recent years, the economy has developed rapidly in various parts of the world, and countries have used many fuels, such as oil and coal, that cause holes in the ozone layer and produce a large amount of greenhouse gases such as carbon dioxide and methane, resulting in a continuous rise in temperature. Floods, and other extreme weather events occur continuously, and extreme weather causes natural disasters that continue to threaten human lives and cause severe property losses [1,2,3,4,5]. The total number of disasters that occurred in 2018 was 282. In the seven continents in the world, the number of disasters that occurred in Asia in 2018 was 129, accounting for 46% of the total. Among the types of natural disasters that occurred in 2018, flood-related disasters accounted for 74% of all disasters; floods made up 39% of the total number of disasters, storms made up 30%, and slope disasters made up 5%. Quantifying flood risk is an important way to develop adaptation and management strategies for decision-making [6,7]. Flood risk can be defined as the product of flood hazard and vulnerability [8,9,10]

Objectives

Methods

Results

Discussion

Conclusion