Potential impact of climate change and extreme events on slope land hazard – a case study of Xindian watershed in Taiwan

摘要

The production and transportation of sediment in mountainous areas caused byextreme rainfall events that are triggered by climate change is a challenging problem,especially in watersheds. To investigate this issue, the present studyadopted the scenario approach coupled with simulations using various models.Upon careful model selection, the simulation of projected rainfall,landslide, debris flow, and loss assessment was integrated by connecting themodels' input and output. The Xindian watershed upstream from Taipei, Taiwan,was identified and two extreme rainfall scenarios from the late 20th and 21stcenturies were selected to compare the effects of climate change. Usingsequence simulations, the chain reaction and compounded disaster wereanalysed. Moreover, the potential effects of slope land hazards were comparedfor the present and future, and the likely impacts in the selectedwatershed areas were discussed with respect to extreme climate. The resultsestablished that the unstable sediment volume would increase by 28.81% interms of the projected extreme event. The total economic losses caused by thechain impacts of slope land disasters under climate change would be increasedto USD358.25million. Owing to the geographical environment of the Taipeimetropolitan area, the indirect losses of a water supply shortage caused byslope land disasters would be more serious than direct losses. In particular,avenues to ensure the availability of the water supply will be the most criticaldisaster prevention topic in the event of a future slope land disaster. Theresults obtained from this study are expected to be beneficial because theyprovide critical information for devising long-term strategies to combat theimpacts of slope land disasters.