宅地域の雨水浸透と流出特性

Abstract

The infiltration tests have been carried out at three field plots in an urban area by theequipment of artificial rainfall type developed by the authors for trial. The infiltration curvesobtained by these field tests have been simulated numerically on the basis of the Richards equationby the method of trial and error for finding the hydraulic properties corresponding to the type ofsurface soil in a field plot.Considering the result of this infiltration study, the runoff characteristics have been examinedin the Kita-Ogurayama residential basin. The results obtained are as follows: The base flow isonly composed of domestic sewage, and groundwater runoff from pervious area is negligible. Run-off from an impervious lot is almost 100 percent. Runoff from a pervious plot occurs only forrainfall over 20 mm in depth, and depends upon the moisture condition of surface soil. Theeffective rainfall intensity for runoff from the pervious plot is able to estimate by solving theRichards equation.These results have been applied to the analysis of runoff from the Kita-Ogurayama residentialbasin. Runoff hydrographs simulated by the kinematic runoff model show good agreements withobserved ones.