Japan Geoscience Union Meeting 2025

Presentation information

Print

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-HW Hydrology & Water Environment

[A-HW25] Near Surface Investigation and Modeling for Groundwater Resources Assessment and Conservation

Sun. May 25, 2025 3:30 PM - 5:00 PM 103 (International Conference Hall, Makuhari Messe)

convener:Jui-Pin Tsai(National Taiwan University, Taiwan), Makoto Taniguchi(Research Institute for Humanity and Nature), Hwa-Lung Yu(Taiwan Society of Groundwater resources and hydrogeology), Tomochika Tokunaga(Department of Environment Systems, University of Tokyo), Chairperson:CHANG PINGYU(National Central University, Taiwan), Jui-Pin Tsai(National Taiwan University, Taiwan), Bo-Tsen Wang(Department of Bioenvironmental Systems Engineering, National Taiwan University), Ying-Fan Lin(Chung Yuan Christian University), Shih-Jung Wang(National Central University)

4:45 PM - 5:00 PM

[AHW25-12] Evaluating Mountain Front and Mountain Block Recharge using stable isotopes and Hydrogeological Groundwater Flow Model in Yamanashi, Japan

*Cuong Quoc Nguyen1, Takashi Nakamura1, Tatsuki Kimura1 (1.International Research Center for River Basin Environment, University of YAMANASHI)


Keywords:Mountain Front Recharge, Groundwater Flow, COMSOL Multiphysics, Groundwater Modeling, Hydrogeology

Several studies have pointed out that mountain recharge is a crucial process in groundwater recharge for the alluvial deposit area. However, the attention to this issue is not paid enough in Japan. Kofu basin, Yamanashi prefecture in Japan, is a typical basin surrounded by mountains, with a very high potential for mountain groundwater recharge in this area. Analyzing stable isotopes (δ18O and δ2H) and chloride concentration in groundwater samples combined with end-member mixing analysis can identify the source of mountain groundwater recharge. The groundwater flow was illustrated using groundwater boreholes and the groundwater flow model simulated by COMSOL Multiphysics. The study found three main sources of groundwater in Yamanashi: mountain front recharge, mountain block recharge, and precipitation/hill-slope recharge, and calculated their contribution in each region. This pilot study in Japan confirms that the groundwater in the basin has a considerable recharge from the mountain’s groundwater source and visualizes the dynamic flow. Sustainable development policies in terms of groundwater use, mountain forest protection, and health risks related to drinking water can be taken advantage of from the study results.