Measures and residents’ attitudes at flooding in Tokyo lowland of Japan

Abstract

The fl ooding including tidal wave and tsunami in Tokyo lowland of Japan has decreased markedly in recent years due to the implementation of measures such levees, weirs, water gates, and other mitigation methods. In order to investigate the attitude of residents toward fl ood hazards in the present day, we distributed a questionnaire concerning fl ood hazards to residents as an example of the Ara River basin in the old downtown area of Tokyo. The questionnaire was given to a random sample of approximately 4000 people living along the Ara River. While the obtained answers clearly illustrate that many of the people living along the Ara River are aware of their designated evacuation area in the event of fl ooding, they doubted whether the refuge sites are safe. This is an issue that must be dealt with through administrative guidance and efforts on the part of the residents. Consequently, the local administrative body must ensure that residents are well informed about hydrological information and the locations of areas that provide refuge from fl ooding.