Relationship between Land Use Transition and Flood Risk in the Nigorigawa River Watershed, Kofu City

Abstract

The study aimed to investigate the impact of the urban planning system on land use transition in the Nigorigawa River watershed in Kofu City, as well as the changes in flood risk within the watershed. For this purpose, we analyzed land use change in the entire watershed over time and a detailed analysis of land use change in the urbanization control area within the watershed. The study results showed that development regulations were implemented smoothly in the river basin after Kofu City was designated as a zoning district in 1971. However, the deregulation of the urbanization control area, which included the formulation of the urban planning master plan in 2001 and the enforcement of Ordinance 3411 the following year, led to the development of residential land in the flood inundation zone.