On the Possibility of Using River Stage Tomography to Characterize the Aquifer Properties of the Choshuishi Alluvial Fan, Taiwan

The fluctuations of groundwater level in a well can be caused by a flood propagating in nearby river due to the interaction of groundwater and surface water. Flood can serve as a natural stimulus without extra manmade excitation for a hydraulic test. Using the time series of groundwater level variation in a well with a known hydrograph of rive stage, the property of the subsurface is possible to be calculated by either deterministic or stochastic approach. The approach can be applied to wells in different locations and explore the spatial distribution of aquifer properties. In this study, the data of groundwater level for wells located from upstream to downstream of Choshu River were analyzed. The correlation between the groundwater fluctuation and river stage are investigated. We explore the possibility of using river stage tomograph as a tool in obtaining aquifer properties.