The wording on a flood hazard map issued by Edogawa Ward in Tokyo has created a stir with the ward essentially telling residents to get out of town in the event of major flooding.
In May, the map was updated for the first time in eleven years and distributed to homes as well as being published on the ward office homepage.
Edogawa is located downstream of two major rivers – the Edogawa River and the Arakawa River. The majority of rainfall across the Kanto region flows into these two rivers.
70% of Edogawa is below sea level at high-tide, protected by levees and flood gates. However, in the worst-case scenario that these measures do not work, the district could go underwater in a severe rain event. The district is no stranger to flooding. It was heavily flooded in 1947 by Typhoon Kathleen and in 1949 by Typhoon Kitty.
It’s not just Edogawa Ward that is in a flood risk zone. The nearby wards of Sumida, Koto, Adachi and Katsushika are also at risk of inundation that could affect as many as 2.5 million residents. Flood waters in some districts could be as deep as 10 meters, and flooding could last between one and two weeks or longer. During this time, residents are warned they may not have electricity, gas, water or sewerage.
What is the local government’s office advice to residents in the event of a flood?
Leave Edogawa and evacuate to a safer ward as soon as possible. Some of their suggestions include Saitama, Chiba, west Tokyo or Kanagawa. For residents who cannot leave the district, they are recommended to try the local evacuation centers or even find safety in tall buildings. These buildings may not have electricity or sewerage in a disaster.
However, if 2.5 million residents from Edogawa and the surrounding four wards attempt to leave the flooded zones via the several bridges, it is expected to create a major traffic jam. The recommended method of early evacuation is to use public transport while it is still operating. During a major typhoon, public transport may stop running, while walking on foot may also be dangerous.
Edogawa’s flood hazard maps can be downloaded via the ward homepage here: