Technical Studies


Analysis of groundwater management strategy in land subsidence prone area

In Taiwan, the importance of integrated flood management over the entire basin are addressed in recent years. The combination of structural and non-structural methods becomes more and more popular in flood regulation project. Following this concept, a land protection strategy should be established in land subsidence prone area which reduce the land subsidence rate and prevent the future inundation risk to be increased due to the continuous land subsidence. To achieve this goal, a groundwater management model is required which determines the optimal pumping strategy.

Since all the researches regarding groundwater management do not consider the inundation risk as a factor in their management models, the reduction of inundation depth cannot be guaranteed even if the optimal pumping strategy obtained by such management model could reduce the land subsidence rate. This study quantitatively determines the relationship between land subsidence and change of inundation depth (or freeboard). Moreover, a groundwater management models was developed which enable the determination of optimal pumping strategies subject to the constraints that the groundwater demands are satisfied and the future inundation depth (or freeboard) will not increase. Through this study, we hope that the use of groundwater management for flood regulation in land subsidence prone area can be promoted. Thus, the reductions of land subsidence and inundation risk can be achieved at the same time.

The study area is Northern Yunlin County and the project will be fulfilled in two years. In the first year, we focus on the development and testing of the groundwater management model. In the second year, the developed model will be integrated into the platform established by the sixth sub-project. Besides, the land protection strategies will be proposed based on the application results of groundwater management model.