出水現象の生起場とその変化過程

Abstract

It has been known that the main component of flood in head water area is directrunoff.This paper consider on the occurrence area of direct runoff in head water area, particularly wood land basin having A layer (high porous surface layer coveringmountain slope), due to the observed results of soil moisture distribution by Dreibelbisand subsurface flow theory.Firstly, the behavior of flow in A layer (subsurface flow) is disclosed theoreticallyfrom the stand point of hydraulics. Basing its result, the significance and the variationprocess of occurrence area of subsurface and surface runoff are analyzed, practicalcalculas method of its variation process is presented.Furthermore, This paper point out the very importance of the occurrence area, relating to runoff analysis, and make clear its role to runoff mechanism.