Annual water balance and its seasonal variation at the southern slope of the Bandai volcano

Abstract

Hydrological variables were measured for three water years at the southern slope of the Bandai Volcano. Annual percolation rates into deeper layers were from about 700 to 1000mm year^-1, and most of the annual precipitation was consumed by the percolation. In comparison with the water balance analysis at the other volcanos, it was pointed out that the percentages of the annual percolation rates to the annual precipitation decreased with the increase of the dissection of valleys. A time series of the percolation into deeper layers estimated by the short-term water balance method showed the monotonous variation. The peak rate occurred in June just after the sonowmelting seasons and the minimum values during a winter. The tendency of the variation on the percolation agreed with the fluctuation of groundwater levels in the study area.