Study on validation method of regional groundwater flow model; Case study for Horonobe area and Niigata basin (Contract research)

Sakai, Ryutaro; Munakata, Masahiro ; Kimura, Hideo; Ooka, Masao*; Seguchi, Mariko*

In the safety assessment for a geological disposal of radioactive waste, it is important to establish validation methods for regional groundwater flow system to estimate radionuclide migration to human environment through groundwater flow. It is necessary to validate the groundwater flow property and flow boundary, as multi-groundwater systems including the different groundwater origins are possible to exist at deep underground. This results show that mixing analysis based on hydrochemical data and spatial plotting with hydrochemical data and thermal data are applicable to validate groundwater flow pattern and groundwater flow boundary in case of Horonobe area. It also demonstrates that mixing analysis based on hydrochemical data and spatial plotting with hydrological and hydrochemical data are applicable to validate the groundwater flow property and groundwater flow boundary in case of Nagaoka area.