[A-HW24] Water Environment and Geology in Urban Areas

[AHW24-P01] Variability of land-use in the catchments of spring water in the western marginal area of Kanto Plain

*Takeshi Hayashi¹, Masaya Yasuhara², Takashi Nakamura³ (1.Faculty of Education and Human Studies, Akita University, 2.Department of Environment Systems, Rissho University, 3.ICRE, University of Yamanashi)

Keywords:Kanto Plain, spring water, land-use change

Marginal areas of the Kanto plain are composed of several topographical units such as alluvial fans (e.g. Arakawa alluvial fan), uplands (e.g. Iruma-Musashino upland), and hills (e.g. Tama hills). These units show both topographical and geological variations. From the hydrological viewpoint, these units have various spring water that had been used as water resources in each area. Although a number of the springs were disappeared in the process of urbanization, there are still many springs in these areas. These existing springs have a wide variety of land-use such as woodlands, agricultural areas, and residential areas in each catchment area.

This study aims to evaluate the effect of land-use change on the water environment of these springs that still remain or are already depleted. In this study, topographical maps that have been published since the Meiji Period and Google Maps have used for understanding the land-use change. As for details of topography surrounding each spring water, 5m DEM published by the Geospatial Information Authority of Japan has been used.
As a result, we found both the existing spring water of which land-use in the catchment area has been historically changed and the disappeared spring water of which land-use has not been changed clearly. We will discuss the effects of land-use change on the processes of the water cycle and the sources of water for these springs.

This study was supported by JSPS KAKENHI Grant Number 19K12293-00.