A GIS-based Support Tool for Exploring Land Use Policy Considering Future Depopulation and Urban Vulnerability to Natural Disasters – A Case Study of Toyohashi City, Japan -

Abstract

In Japan, where the aging society is progressing due to depopulation and a high risk of natural disasters, such as earthquakes and floods, many actual urban master plans (MPs) do not consider the relation between countermeasures for future depopulation and disaster mitigation. Local governments do not regard long-term depopulation as a viable opportunity to establish land use policy that promotes reasonable land use by aggregating urban land use to areas with low risk.This paper proposes the development of a tool for the exploration of land use policy that realizes an intensive urban structure by considering future depopulation and urban vulnerability to natural disasters. The tool serves as a GIS-based database of information about disaster risk for floods and earthquakes, future populations, previous and existing urban land use conditions, urban structures. The following results are obtained from a case study. First, experts such as local government can distinguish areas with high risk by two types of areas: 1) areas characterized by a slow progression of depopulation and aging and 2) areas in which it is difficult to sustain the local community and provide public services due to the progression of depopulation and aging. The results of this study can confirm various data on urban structures, such as transportation infrastructure, and core urban areas that provide life services and land use history. Reasonable land use countermeasures for reducing disaster risk can be explored by considering previous and existing conditions of urban land use.