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Up to 2.5 mil. people in Tokyo's low-lying areas may be affected by flooding

TOKYO -- Five wards in low-lying areas of eastern Tokyo released a comprehensive evacuation plan on Aug. 22 in the event of major river flooding, estimating that some 2.5 million residents -- or more than 90 percent of the population in the area -- could suffer damage in a worst-case scenario.

The five wards -- Sumida, Koto, Adachi, Katsushika and Edogawa wards where the ground is below sea level at full tide -- will ask their residents to swiftly evacuate to neighboring prefectures such as Chiba and Saitama, east and north of Tokyo, respectively, as well as the western part of the capital, in the event of major flooding.

A council set up by the five ward's governments has been looking into the evacuation plan. If localized downpours trigger the Arakawa River and Edogawa River to flood simultaneously and a mega-typhoon causes a tidal surge, over 90 percent of areas in the five wards could suffer damage. Most of the areas along the Arakawa River will be submerged under water at a depth of 3 to 10 meters. Floodwater will not recede for at least two weeks in areas including the western part of Edogawa Ward, home to some 1 million residents.

Under the emergency plan, an evacuation advisory will be issued for residents in the five wards to flee to Chiba and Saitama prefectures and other areas 9 to 24 hours before flooding is forecasted to hit the area, by referencing an emergency high tide warning issued by the Japan Meteorological Agency and other information.

It is, however, expected to be difficult to secure wide spaces where such enormous numbers of residents can take shelter, posing a risk for possible confusion in evacuation efforts. "We would like to ask residents to secure evacuation sites on their own," a representative of the council said.

(Japanese original by Masaki Takahashi, Tokyo Bureau)

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