ANALYSIS ON FLOOD DAMAGES IN URBANIZATION CONTROL AREA: A CASE STUDY OF DAMAGES BY TYPHOON HAGIBIS IN NAGANUMA DISTRICT, NAGANO CITY, JAPAN

Abstract

Land use regulation is a fundamental measure of flood mitigation and climate change adaptation for reducing the amount of exposure in floodplains. In Japan, land use regulation for flood mitigation has been considered in the classification area under the City Planning Act and the Location Normalization Plan under the Act on Special Measures Concerning Urban Reconstruction. However, mitigation effects and operational challenges have not been fully elucidated. In this study, we analyzed the characteristics of flood damage in the urbanization control area in Naganuma District of Nagano City, which was severely damaged by the Chikuma River levee break triggered by Typhoon Hagibis in 2019. The analysis, which adopted building point data, determined that land use regulation by area classification played a role in reducing damage in the area. However, at the community level, it was confirmed that more buildings were located in areas with high flood hazards owing to the development of new houses and businesses associated with the development of infrastructure.