Abstract
We developed a method to lump runoff processes of slope systems taking into account a distribution of basin topography. In our method, we measure topographic quantities such as slope length and so on by using the Basin Geomorphic Information System (BGIS), and lump slope systems by using the cluster analysis technique on the assumption that the similarity of runoff characteristics among slope elements is evaluated with that of topographic characteristics. Applying our method to an actual basin, we obtained the following conclusions:(1) Our method reduced an amount of runoff calculation to about one-20th of that without employment of our method, (2) Coefficient of variation of a topographic quantity was valid for the criterion for giving the number of clusters.
