Climate Change Impact on Groundwater Recharge: A Case Study in Taiwan

Climate change may result in variety of climate and streamflow characteristics. These will further induce influences of groundwater recharge. Therefore, this study assessed the impact of climate change on groundwater recharge through evaluating the change of streamflow under different scenarios. Projection of precipitation or temperature impacted by climate change is of great uncertainty, thus three Global Circulation Models (GCMs), i.e. HADCM3, CGCM2 and GFDL, with two kinds of climate change scenarios, i.e. A2 and B2, are adopted in this study to reduce the uncertainty. Simple downscaling method is utilized to downscale the precipitation and temperature data from global scale to local scale, which is then used as input in the Hydrologiska Byråns Vattenbalansavdelning (HBV) model to project the change of streamflow in the period of 2010 to 2039. Besides, a groundwater numerical model of Taipei basin in Taiwan will be constructed by Processing Modflow and verified by collected historical data. River elevation is simulated by HEC-RAS model with observed streamflow data and streamflow projected by HBV model, and the river package in the PM model is used to simulate the groundwater recharge for now and future scenarios. Finally, monthly and seasonal groundwater recharge impacted by climate change will be investigated for different GCMs and scenarios.