The Hazard potential and impact of subsidence under the climate change in the Tainan Area

The problem of subsidence in Tainan is relatively mild. However, the aquaculture is prosperous development along the coast of Tainan. If there is no proper plan and management of groundwater resources, the problem of subsidence will become serious in the future. Tainan is exposure in high risky disaster zone for flood and climate change, the potentiality for future heavy rain and flood is as well as high. Therefore, to fully understand the climate change and its effect on subsidence will assist the plan and management for water and land resources in the early stage and avoid irrecoverable damage and disasters brought by subsidence. This research combines nonlinear poroelastic model and gray system model to predict and estimate the subsidence in the Tainan area. Moreover, this study aims to estimate the change of quantity in groundwater under the climate change, to predict and further estimate the settlement under the climate change. Lastly, to analyze both the hazard-potential and impact of subsidence under the climate change. Considering the increase of 31.7% groundwater pumping due to the climate change, the maximum settlement in 2039 is 1.03 meter in Tainan. The main area is near Annan, Xuejia, and Beimen Districts. The hazard-potential of subsidence in the Tainan areas is under the middle and low levels. Due to the climate change, the area of middle hazard-potential of subsidence is mainly extended from Annan, Xuejia, and Beimen areas. The major effect of the climate change on Tainan is the increasing settlement. The maximum settlement is 0.25 meter in Anna District. If considering the rising sea level, another effect brought by the climate change, Tainan area definitely will turn into a highly risky area for flood. In conclusion, it's necessary to process the land and water resources plan and management to alleviate settlement and prevent the disaster brought by serious subsidence.