History of Land Use in Old River Channels in Arakawa Lowland based on Classification of Topography

Abstract

River is a factor which determines environmental characteristics and scenery of an area; therefore, it is important to clarify the history of land use in old river channels in order to understand its local characteristics. In this study, the middle stream to downstream area of Arakawa River which is being vast floodplain is investigated. The objective of this study is investigating the correlation between Arakawa River’s topography and land use history in its old river channels. The land use history analysis was conducted by analyzing topographical map with scale 1/25,000, the old version of a topographical map, and aerial photographs. The GIS data was developed from topographical classification of the Arakawa River basin in order to clarify the relationship between topography and old river channels. Furthermore, a field research was conducted to obtain actual land use data. The result shows that the combinations of topography and old river channels can be classified into four types. From the study above, the land use of old river channels was changed caused by its land form and social factor in that area. It is also found that the history of land use in the old river channels from the Taisho Period to the present has been changed.