Effect of Optimal Groundwater Management on Flood Hazard for Land Subsidence Prone Area
|關鍵字:||地層下陷;地下水管理;優選;出水高;淹水潛勢;Land Subsidence;Groundwater Management;Optimization;Freeboard;Flood Hazard|
In this study, the land subsidence and inundation models were utilized to numerically investigate the effects of pumping induced land subsidence on the freeboard and inundation depth. After realizing how the freeboard and inundation depth would be varied due to long-term land subsidence, a groundwater management model was developed to mitigate the effect of land subsidence on flood hazard. The management model determines the proper pumping strategy such that the goals including (1) controlling land subsidence; (2) preventing the flood hazard to be deteriorated in the future; and (3) satisfying the groundwater demand can be optimally achieved. The study area is northern Yunlin drainage system. To investigate the effects of land subsidence on flood hazard, firstly, the spatial distribution of accumulative land subsidence between 2012 and 2021 was predicted by a process-based land subsidence model. The digital elevation model (DEM) and channel geometry in 2021 were produced based on the predicted land subsidence field along with the present topography data. Then, the freeboard and inundation depth before and after ten years land subsidence were simulated by the SOBEK Suite. To mitigate the effect of pumping induced land subsidence on flood hazard, a groundwater quantity management model was developed. The management model determines the optimal pumping patterns which prevent the flood hazard to be increased due to long-term subsidence while satisfy the groundwater demand. Five scenarios were considered and the corresponding optimal pumping patterns for the study area were obtained by the developed management model. The results show that groundwater management can efficiently prevents the flood hazard to be deteriorated. Therefore, in addition to traditional structure measure, groundwater management should also be incorporated into flood regulation project for land subsidence prone area.
|Appears in Collections:||Thesis|