Abstract
Short-time heavy rainfall disaster occurred in Osaka City on 27 August 2011. Hourly precipitation was 77.5mm which is the maximum record in Osaka. The purpose of this study is to find the vulnerable factors in pluvial flooding in densely urbanized area. Field survey was conducted in Kita-ku, Osaka City on 28 August 2011 and reproductive calculation was carried out with this rainfall. This research indicated the follows. Roads in high-density urbanized district turn into channels by heavy rainfall. The partial low-lying area such as "bowl-shaped" is prone to floods as much as underpasses under highway and railroad bridges. Store employees may fail to evacuate from the under and above stores due to a take action to prevent a flooding. In flood analysis, to improve the results it is necessary to consider the micro topography.
