JDR Vol.16 No.3 pp. 321-328
doi: 10.20965/jdr.2021.p0321


Vulnerability to Mega Underground Inundation and Evacuation Assuming Devastating Urban Flood

Yutaro Nakasaka and Taisuke Ishigaki

Department of Civil, Environmental and Applied Systems Engineering, Kansai University
3-3-35 Yamate-cho, Suita, Osaka 564-8680, Japan

Corresponding author

September 29, 2020
January 9, 2021
April 1, 2021
pluvial flood, underground inundation, evacuation, flood board, densely urbanized area

In urban areas of Japan, there are numerous underground spaces, such as subways and shopping malls. These areas hold the possibility of being inundated not only above the ground but also underground when intense rainfall causes pluvial flooding. For this reason, it is necessary to take measures to anticipate urban floods. In this study, an analysis of inundation on the ground surface and underground spaces was performed, and the risk of underground inundation was evaluated using the index of safe evacuation. In addition, as one of the countermeasures against underground inundation, the effect of flood boards on inundation prevention was examined. Furthermore, the factors for improving the success rate of evacuation are discussed by simulating the evacuation of users from an underground mall during inundation. From the results, the water inflow to underground spaces was larger as rainfall was greater, and the reduction effect of flood boards on underground inundation was only temporary if the inflow to the underground mall was large. In addition, the success rate of evacuation depended on the timing of evacuation because the flooded water spread broadly and rapidly across the underground mall. These results show that users in an underground mall should move with a quick response to flash flood from high intensity rainfall and would be useful in creating a safe and prompt evacuation plan.

Cite this article as:
Yutaro Nakasaka and Taisuke Ishigaki, “Vulnerability to Mega Underground Inundation and Evacuation Assuming Devastating Urban Flood,” J. Disaster Res., Vol.16, No.3, pp. 321-328, 2021.
Data files:
  1. [1] T. Takahashi, H. Nakagawa, and I. Nomura, “Simulation method on inundation in an underground space due to intrusion of overland flood flows,” Annuals of Disaster Prevention Research Institute, Kyoto University, No.33 B-2, pp. 427-442, 1990 (in Japanese).
  2. [2] K. Toda, K. Inoue, T. Nakai, and R. Oyagi, “Hydraulic model test of inundation water intrusion in underground space,” Proc. of the 14th Congress of Int. Association for Hydro-Environment Engineering and Research and Asia Pacific Division (IAHR-APD), pp. 1403-1409, 2004.
  3. [3] K. Toda, K. Inoue, and S. Aihata, “Urban Flood Analysis with Underground Space,” W.-H. Ip and N. Park (Eds.), “Advances in Geosciences – Vol.4: Hydrological Science (HS),” pp. 47-56, World Scientific, 2006.
  4. [4] K. Toda, D. Yamamoto, N. Yoneyama, and Y. Kuwano, “Risk analysis of underground inundation considering evacuation difficulty,” Proc. of the 8th Int. Conf. on Urban Drainage Modelling, 2-C3, 2009.
  5. [5] K. Toda, “Urban Flooding and Measures,” J. Disaster Res., Vol.2, No.3, pp. 143-152, 2007.
  6. [6] M. Sekine and J. Nakayama, “Numerical simulation of inundation in underground space in highly urbanized area in Tokyo,” Proc. of the 8th Int. Conf. on Urban Drainage Modelling, 2-C1, 2009.
  7. [7] T. Ishigaki, Y. Onishi, Y. Asai, K. Toda, and H. Shimada, “Evacuation criteria during urban flooding in underground space,” Proc. of the 11th Int. Conf. on Urban Drainage (ICUD), 2008.
  8. [8] T. Ishigaki, Y. Asai, Y. Nakahata, H. Shimada, Y. Baba, and K. Toda, “Evacuation of aged persons from inundated underground space,” Water Science & Technology, Vol.62, Issue 8, pp. 1807-1812, 2010.
  9. [9] T. Ishigaki, T. Ozaki, T. Inoue, H. Shimada, and K. Toda, “Drainage system, rainwater flooding and underground inundation in urban area,” Proc. of the 12th Int. Conf. on Urban Drainage, PAP005466, 2011.
  10. [10] T. Ishigaki, N. Asano, M. Morikane, T. Ozaki, and K. Toda, “Extreme Hazard of Pluvial and Tsunami Floods in a Densely Urbanized Area,” Proc. of the Int. Conf. on Flood Resilience: Experiences in Asia and Europe (ICFR 2013), 2013.
  11. [11] Ministry of Land, Infrastructure, Transport and Tourism (MLIT), (in Japanese) [accessed September 28, 2020]
  12. [12] T. Ishigaki, R. Kawanaka, T. Ozaki, and K. Toda, “Vulnerability to Underground Inundation and Evacuation in Densely Urbanized Area,” J. Disaster Res., Vol.11, No.2, pp. 298-305, 2016.
  13. [13] H. Kho, T. Ishigaki, T. Ozaki, and K. Toda, “Evacuation from inundated underground shopping mall under extreme weather condition,” Proc. of Symp. on Underground Space, Vol.23, pp. 103-108, 2018 (in Japanese).
  14. [14] T. Ishigaki, Y. Baba, K. Toda, and K. Inoue, “Experimental study on evacuation from underground space in urban flood,” Proc. of the 31st IAHR Congress, 2005.
  15. [15] Y. Asai, T. Ishigaki, Y. Baba, and K. Toda, “Safety analysis of evacuation routes considering elderly persons during underground flooding,” J. of Hydroscience and Hydraulic Engineering, Vol.28, No.2, pp. 15-21, 2010.
  16. [16] T. Ishigaki, K. Toda, Y, Baba, H. Nakagawa, and H. Shimada, “Difficulty of evacuation from underground space in urban flood,” Proc of the 7th Int. Conf. on Hydroinformaitcs (HIC 2006), Vol.1, pp. 614-620, 2006.
  17. [17] R. Kawanaka, M. Yoshikawa, and T. Ishigaki, “Factors for Improving Evacuation Rate in Safety from Underground Space,” J. of Japan Society of Civil Engineers, Ser. F2 (Underground Space Research), Vol.70, No.1, pp. 13-19, 2014 (in Japanese).

*This site is desgined based on HTML5 and CSS3 for modern browsers, e.g. Chrome, Firefox, Safari, Edge, Opera.

Last updated on Apr. 13, 2021