Study on assessment scenarios of natural phenomena effected on groundwater flow system; Case study for the sea-level change (Contract research)

Sakai, Ryutaro; Munakata, Masahiro ; Kimura, Hideo

It is important to evaluate effect on the groundwater flow system by the natural phenomena in the safety assessment of geological disposal of radioactive waste through a survey of recent scientific informations. In this report we study about the scenario of sea level change effecting on the groundwater flow system which is very important for a safety of disposal facility in costal area. As a result, this study show that the non-current paleo-fresh water at present is possible to start to discharge at sea floor in the next glacial period by denudation of marine-clay sediments and to grow stagnant again in the next interglacial period by deposition of marine-clay sediments. Therefore it is important to predict the scenario considering the denudation and deposition correlated with transgression and regression that could affect the change of groundwater flow characteristics during the glacial and interglacial period.