Flood Refuge Measures In The Vicinity Of Urban Rivers

Flood hazards in urban areas have decreased markedly in recent years due to the implementation of measures such as dikes, weirs, water gates and other mitigation methods. Consequently, the population of developed or redeveloped urban areas near river basins and coastal areas has increased considerably, and a concomitant increase has been observed in the number of high-rise office buildings and apartments on the alluvium of old urban rivers. While the residents of these structures are sensitive to earthquake damage, they are relatively unaware of the risks associated with flooding. While several flood refuges exist in the vicinity of urban rivers, the intended purpose of these refuges has come to be regarded as that of earthquake emergency measures rather than a measure intended for flooding. Consequently, the placement of many of these emergency refuges does not consider the risk of inundation. In this report, the present condition of such refuge sites in the low lying areas of Tokyo is examined. We also investigated the attitude of residents living in high-rise apartment buildings and detached houses toward flood hazards. Finally, we proposed flood refuge measures that could be implemented to minimize the risk of disaster.