2011 Volume 24 Issue 6 Pages 337-347
Recently, a main subject of flood control measurement does not depend on dams. In the Tone river, inspection of design flood discharge is expected. Storage function method, one of the lumped rainfall-runoff models, has been used for flood control planning as a technical standard in Japan. When Catherine Typhoon attacked in 1947, there were no dam reservoirs in the upper stream of Yattajima standard point of observation, and also hydrological data were not sufficient. Based on the analysis of storage function model, we have checked how the flood risk has been reduced by dam construction work after the World War II. In this study, runoff analysis was carried out using large rainfall events which included Catherine Typhoon, and also effect of channel storage with branch river junction was estimated. The results can be summarized as follows. Rainfall distribution is influenced by geomorphologic characteristics, and then it is necessary to consider the spatial distribution of rainfall in the runoff analysis. Comparing with the peak discharge and total amount of discharge at the confluence point computed by 1D models, the effect of channel storage can be quantitatively estimated.
