The investigated area is a small, talus deposit in the foot of Mt. Oasa. The investiga-tion of the mechanism of ground water in this area was carried out.
It was clarified that the ground water storage was active in this small talus deposit.
The concentration of tritium covered 10 to 155 TR.
The spring water in high elevation and the ground water in the deep layer showed_ the maximum value and minimum value respectively.
This fact indicates that the precipitation exuded comparatively fast in the spring_ water in high elevation.
A ground water. recession curve showed the variation of base flow with time during periods of little or no rainfall. This decrease is shown in approximating the formula. of Q = Q₀^-at.