Abstract
To clarify the runoff process on a hillslope, observations of the discharge, groundwater level and soil moisture were made on a hillslope consisting of weathered granite in the south-east area of Shiga Prefecture. The discharge was produced mainly by unsaturated flow, and it was not con-cerned with the average of the soil-moisture storage on the entire slope, but with that of the lowest part of the slope. By an analysis of the two-dimensional potential distribution, the direction of soil-water flux during the base flow was parallel to the slope angle. A model is proposed on the basis of the observation results. In this model, the effect of three-dimensional topography and the unsaturated flow process have been included. The model estimates not only hydrographs, but also soil moisture variations at each point on the slope. The observed changes of soil moisture and the hydrographs can be reproduced by this model.
