Monitoring of pore water pressure and groundwater chemistry at MSB-2 and MSB-4 boreholes in the MIU construction site; April, 2010 - March, 2011

Hagiwara, Hiroki  ; Shingu, Shinya; Kurita, Kazuaki*; Eguchi, Keita*; Horita, Masakuni*; Mizuno, Takashi   

Japan Atomic Energy Agency has been carried out investigations to understand the fluctuation of groundwater chemistry related to the shafts excavation at the Mizunami Underground Research Laboratory in Mizunami City, Gifu prefecture, Japan. The data for pore water pressure, water temperature and groundwater chemistry have been provided from two surface-based boreholes, MSB-2 and MSB-4 boreholes, installed a modular multilevel groundwater monitoring system (MP system). The monitoring has been conducted once in a month since April 2003. According to the results, the shaft excavation has caused drawdown of the hydraulic head and change in the groundwater chemistry in the MIU construction site. In this report, the data of monitoring at the MSB-2 and the MSB-4 boreholes from April 2010 to March 2011 were compiled. In addition, the monitoring results at the DH-2 borehole as part of Regional Hydrogeological Study project, are summarized as an appendix.