Index of freeze and thaw intensity was calculated by a thermal conductivity analysis using meteorological and topological input data for the Kizu River basin. In the analysis, all the detectable bare slopes were extracted by aerial photographs and the topological factors such as area, altitude, gradient and direction of each bare slope were obtained by GIS technique. Annual sediment inputs to five dam reservoirs constructed on tributaries of the Kizu rivers were calculated from change of topography in the reservoirs. Correlation between the index of freeze and thaw intensity and the annual sediment inputs were analyzed and the clear correlation indicates the availability of the freeze and thaw index estimating the sediment production and discharge. The sediment production and discharge from the total watershed area of the Kizu river was estimated to be 14,800m3/year by the correlation, it seems to be overestimated comparing to the value by a past research. The method estimating the sediment production from a total river watershed can be improved by a higher accuracy method of bare slopes extraction and including a distinction of geology in the estimation.

Key words�Fsediment production, the Kizu River, freeze and thaw