Assessment of climate change impacts for lowland flooding management in southwestern Taiwan

Flooding is an inevitable, reoccurring, and the most damaging disaster in Taiwan. Flooding problem is further worse in land subsidence areas along southwestern coast of Taiwan due to groundwater overdraft. Increasing number of people is threatened with floods owing to climate change since it would induce sea level rise and intensify extreme rainfall. Assessments of flooding impact depend not only on severity of flooding, possible damage of assets exposed to floods should also be simultaneously considered. This paper aims at exploring how climate change might impact the flooding of lowland area in Taiwan to support policy decisions. The flood-prone Yunlin coastal area, located in southwestern Taiwan, is chosen as case study. The results reveal that increased flooding severity is obtained for longer recurrence-interval storms with climate change. Performance of currently implemented flood-mitigation measures is insufficient to reduce flooding vulnerability when facing with climate change. However, the scenario suggested in this study to sustain room for floods might efficiently reduce flooding due to climate change. The suggestions provided in this study could support the decision process and help easing the flooding problems of lowland management in Taiwan under climate change.