Spatiotemporal Analysis of Groundwater Recharge Trends and Variability in Northern Taiwan

Abstract

In this study, the base flow estimation method was used to assess long-term changes of groundwater recharge in Northern Taiwan. The Mann-Kendall test was used to examine the characteristics of the trends. This was followed by trend slope calculation and change-point analysis. The annual groundwater recharge was found to exhibit a significant upward trend for the Fushan and Hengxi stations (Tamsui river basin). On the other hand, the Ximen Bridge station (Lanyang river basin) recorded a significant downward trend. Calculations showed that the rate of change for the Fengshan and Touqian river basins was small (less than 10%). However, that for the following stations was greater than 30%: Fushan, Hengxi, Ximen Bridge, and Niudou (also in the Lanyang river basin). The results of the change-point analysis further indicated a significant change-point for the annual recharge at Fushan, Hengxi, and Ximen Bridge stations in 1999, 1983, and 2001. The findings can be used for regional hydrological studies and as reference for water resource planning.