亀の瀬地すべり地の地下水流について

Abstract

Ground water flow regime of the Kamenose landslide area in Osaka Prefecture was investigatedfrom 1964 to 1969 as a part of a synthetic research of the Kamenose landslide. The results of theinvestigations of the ground water level and the geological structure suggested that the ground waterin this area can be treated as phreatic water. It was also confirmed by the result of the logging ofthe ground water flow in the boreholes. The distribution of ground water storage can be givenfrom a contour map of the water table and a geological map showing the thickness of permeablelayer (mainly weathered andesite). The path of significant ground water flow was estimatedthrough the ground water tracing and the geochemical investigation of land waters. It was foundthat the main ground water vein exists in the zone where the landslide motion was significant. Theresult of the investigation of water balance in the watershed of a brook in the landslide area showedthat the net recharge of the ground water accounts for about 60% of the annual precipitation. Thedischarge of the springs and the artificial drainage works, and the base flow of the brook in thewatershed are summed up and compared with the ground water recharge. It is shown that about60% of ground water recharge flows away without appearing on the ground surface in this area.It is generally said that the ground water. Flow in landslide areas usually exists as ground waterveins in the underground channels. It is demonstrated that, in such a case, distribution of thepotential of ground water, direction of significant flow, and water balance of each part of thewatershed must firstly be investigated to know the fundamental network of the ground water flow, and to know, then, its more detailed structure through further investigations.