A Study of shallow groundwater flow based on groundwater level and geological structures in the Horonobe area, Hokkaido

Yokota, Hideharu; Yamamoto, Yoichi; Maekawa, Keisuke  

It is important for assessing the safety of geological disposal of high-level radioactive waste to understand shallow to deep groundwater flow as the driving force of mass transport. JAEA has been carrying out the surface hydrological investigation in the Horonobe area, Hokkaido. Results of groundwater-level observations, and relationship between distributions of groundwater-level and geological structures suggest that constructions of underground facilities have no effect on shallow groundwater-level fluctuations, and that water infiltrate from ground surface into shallow underground in the snow covered season, and that water infiltrate into deeper underground along faults. In the future, it is necessary to quantitatively assess the water infiltration and recharge based on directly and/or indirectly observed data of evapotranspiration and soil moisture content by weighing lysimeter and ADR method soil moisture meter, and tensiometer.