3:30 PM - 3:45 PM
[AHW22-01] Distribution of Modern, Paleo and Formation water in Plains and Basins in Japan
Keywords:Groundwater age, Residence time, Groundwater flow system
In the presentation, we will introduce several conceptual maps in middle and northern Japan. As a result, the boundary of Modern and Glacial waters locates at a shallower than 200 m, in where soft Quaternary sedimentary rock area with gentle topography. This result emphasized that even soft Quaternary rock (generally with high permeability) can form the lower no-flow boundary of the groundwater flow system in respect to the Modern groundwater. The Formation water locates at depths of deeper than 500 m but seems to have wide transition zones.
On the other hands, the Modern water presents deeper than 200 m at volcanic areas. In these areas, the steep topography and high permeable geology seem to induce a high driving force of groundwater flow and produce the large scale of Modern groundwater flow system. At the coastal zone at the foot of Mt. Fuji, the Modern water is found at a depth of 250 m. The result above is the actual demonstration of the relationship between topography and the distribution of the Modern water.