This paper examines the relation between basin modeling being necessary to flood analysis by a kinematic wave runoff model and characteristics of hydro-geomorphological quantities related to runoff phenomena in a river basin, in which hydro-geomorphological quantities are stream length，drainage area，slope length, stream gradient, slope gradient and so on. The outline is as follows,
First, a standard basin model is set up, in which the origin of streams is practically regarded as a point being the ratio w/l = 1 on a topographical map with the scales of 1/25000 or 1/10000, where w is width and l is depth in the bend of a contour line in a topographicalb map.
Second, measuring methods of slope garadient for valley side in modeling basin are compared. And it is concluded that a proposed technique named a valley line method by weighted mean is pratical use and useful.
Third, it is clarified how the mean and distnbution of hydrogeomorphological quantities change with incresing successively the standard order of unit model basin, considering more lumped basin model from the practical standpoint on flood runoff analysis.