Abstract
　An increase in surface rainfall-runoff followihg urbanization of hilly regions augments the flood danger in the downstrem basin. In order to cope with this problem, storm-runoff control should be considered as regards the entire urbanized district.
In the study, a storm-runoff control method, which makes part of the rainfall infiltate the soil with the aid of buried porous pipe, is examined. The mechanisms of rainfall infiltration from the pipe, es pecially the relationships between infiltration quantity, water pressure in the pipe, rainfall infiltraion from the earth surace and initial soil moisture content, are clarified by means of experiments and numerical analysis. Next, the numerical calculations for 4 kinds of soil are carried out to clarify the relationship between permeability of soil and the infiltration quantity from the porous pipe. In addition, an equation for the infiltration quantity from the porous pipe is prsented. Finally, assuming a case where porous pipes are installed in the hilly residential area in the northern disthict of Uji city, a rainfall-runoff analysis is conducted and the storm-runoff effect is comcretely presented.

【キーワード】：都市化, 洪水, 埋管浸透法, 出水抑制, 土壌水分

*京都大学防災研究所
Disaster Prevention Reseach Institute, Kyoto Unive.