Ground-water Fall Line at Ooizumi-mati, Western Suburb of Tôkyô City, with Special References to its Influence on the Development of Cultural Landscape

Abstract

The writer found a ground-water fall line 6km long on the upland of Ooizumi-mati, western suburb of Tokyo. City. The ground-water table drops abruptly northward 6m on the line. The trend of the line is east to west. Therefore the depth of the ground-water below the surface in the northern part of the upland is greater than that in the southern part. The water table on the southern side of the fall line is subject to marked seasonal variation. The water in water table wells is deep. during the wet season. The pH of the ground water across the line also undergoes marked changes. There were wide woodlands and a few rural settlements in the upland north of the line until quite recently. The deep ground-wat-er may contribute to the latest reclamation of the northern part of the upland. Many dwellings, schools, and factories are being built within the woodland in connexion with the city planning. There are narrow, perched water areas in the upland, where the shallowness of the ground water helps the developement of small ru-ral settlements.