山地小流域に関する陸水学的研究(I) 風化花崗岩地域からの土砂および溶解物質の流出

Abstract

As a part of IHD researches of the Lake Biwa area, it is intended to investigate theinteraction between the hydrologic cycle and the geomorphologic processes such as weath-ering, denudation of slopes, and channel processes in small mountaineous watersheds.At first, four month's observation on the yield of water, dissolved matter, and sedimentsfrom the experimental basin in weathered granite region of the Daido River area wascarried out from the summer to the autumn of 1967.The runoff water from the basin involves small amounts of ~~and UC05ions, which suggests that the chemical weathering processes are less significant than themechanical ones. The base flow is of good durability, and is attributable to the storagein the sand deposit in the tributary valleys due to its similarity in water quality to thesurface runoff water.Soil conservation practice was carried out in the autumn of 1966, and little sand wassupplied from the bare mountain slopes. The bed load material deposited at the gaugingstation is attributable to the erosion of the sand deposit in the valleys.