The study uses weather generation models to generate future daily rainfall and temperature, and incorporates a land coverage model to simulate future land use changes. These future scenarios are then simulated by a rainfall runoff model to study their impacts on basin discharge, river, and groundwater levels. The Fengshan Creek basin in northern Taiwan is selected as test site. The RCP2.6 scenario is adopted to project future climate. The hydrological impacts, in the context of groundwater, for the near future (2020 - 2039), future (2050 - 2069), and distant future (2080 - 2099) are discussed. Simulations indicate that the influence of climate change is more important compared to local land cover changes at our study site. Both river stage and groundwater levels are influenced under future scenarios, but seasonally rather than annually; the dry and wet seasons are amplified. The results indicate that future water resources will be scarce in the dry season and more abundant in the wet season. In addition, changes in groundwater levels for mountainous region are more significant than in the downstream flat areas.