Abstract
Direct runoff, which disappears in few days after a storm, was separated to discuss relationships between retention, total rainfall and soil moisture deficit in three experimental catchments of different types of land use. It was concluded that the effect of initial soil moisture condition on the retention could be evaluated quantitatively by the deficit and different properties of the retention were found among the catchments. A water budget concept was applied to investigate a property of percolation as rainfall loss during a storm. Linear relationships were found between duration time and the amount of percolation and it was revealed that the intensity of percolation is dependent on properties of soils and bed rocks and types of land use in the catchments.
