Disaster risk analysis using geospatial information (GIS)

Estimation of inundation by flood and high tide for public health centers in Tokyo

Abstract

We analyzed disaster risks associated with the estimate of river flooding/overflowing as well as high tide inundation for public health facilities, including 160 public health centers in Tokyo, based on a map of the estimated high tide inundation area for the Arakawa and Tone Rivers published by the Ministry of Land, Infrastructure, Transport and Tourism in the digital national land information. As a result, it was found that 41 facilities near the Arakawa River (25.6% of the total) and 18 facilities near the Tone River (11.3% of the total) were assumed to be inundated by the expected maximum scale of flood.46 public health center facilities, or 28.8% of the total, were assumed to be inundated by the expected maximum scale of high tide. As a countermeasure against inundation in these public health facilities, it is considered necessary to take tangible measures such as relocating the facilities to a location with a lower risk of flooding, setting up backup offices to secure alternative functions, and installing watertight panels. In addition, it is considered that intangible measures such as the formulation of a timeline, i.e., a disaster prevention action plan, which organizes disaster prevention action procedures in chronological order, are necessary so that people working at public health center facilities can evacuate quickly.