5:15 PM - 6:45 PM
[AHW24-P04] Understanding Groundwater Flow Processes in the West Kofu Basin

Keywords:Groundwater flow processes , Kofu basin, Green tuff, water stable isotope
The Kofu Basin located in central Japan is surrounded by mountains, and the alluvial lowland in the center of the basin contains a thick layer of sand and gravel that stores a large amount of water. The groundwater is widely used for drinking and industrial purposes in this region.
This study focused on the western Kofu basin, namely the Minami Alps mountainous region, to identify the mountain groundwater flow processes. River water and groundwater samples were collected from the western part of the Kofu Basin, as well as mountain river water at elevations ranging 400m and 1500m (the Kofu Basin has an elevation of roughly 250m). These samples were then analyzed for dissolved ion concentrations, and it was found that groundwater of the Midaigawa alluvial fan in the western Kofu Basin was most likely to have been recharged by "mudstone" and "interbedded sandstone and mudstone" in the Minobu formations in Fujikawa group. It was also found that gypsum (Ca-SO4) contained in green tuff is likely to have played a significant role in the water quality formation.
This presentation will add to the results of water stable isotope analysis and will be about the water flow and water quality formation.
This study focused on the western Kofu basin, namely the Minami Alps mountainous region, to identify the mountain groundwater flow processes. River water and groundwater samples were collected from the western part of the Kofu Basin, as well as mountain river water at elevations ranging 400m and 1500m (the Kofu Basin has an elevation of roughly 250m). These samples were then analyzed for dissolved ion concentrations, and it was found that groundwater of the Midaigawa alluvial fan in the western Kofu Basin was most likely to have been recharged by "mudstone" and "interbedded sandstone and mudstone" in the Minobu formations in Fujikawa group. It was also found that gypsum (Ca-SO4) contained in green tuff is likely to have played a significant role in the water quality formation.
This presentation will add to the results of water stable isotope analysis and will be about the water flow and water quality formation.