Low-lying ward boosts rain forecasts

by Masaaki Kameda

Staff Writer

Susceptible to flooding, Tokyo’s Edogawa Ward, 70 percent of which is below sea level at high tide, will start posting rainfall forecasts on its website from Thursday in a pilot program aimed at improving its flood control as much of the nation grapples with a spate of torrential downpours.

Edogawa is apparently the first municipality in the Kanto region to provide estimates of rainfall, said Naomasa Tachihara, section chief of the ward’s civil engineering division.

“Much of the land in the ward is below sea level, so when it rains a lot, the water tends to rise and cover some roads. Residents are very concerned about downpours,” he said. Also, some 20 percent of the ward is water: The Edogawa and Arakawa rivers run through it to empty into Tokyo Bay, according to Tachihara.

“We would like the residents to obtain information from the website to prevent flood damage,” he said.

The pilot program is part of a larger project by the National Research Institute for Earth Science and Disaster Prevention, based in Tsukuba, Ibaraki Prefecture, to help make cities more resistant to extreme weather.

The information for the website is based on the “X Band Multi-Parameter Radar” developed by the institute, which can forecast rainfall more precisely and faster than the previous system, according to Tachihara.

Instead of updating information for a square kilometer every five minutes, the new radar will give updates every minute for areas as small as 250 sq. meters.

The pilot program runs until the end of March 2015.

Tachihara also said the ward hopes to get feedback from local residents via the website to improve its flood-control measures.

The heavy rainfall that has struck many parts of Japan over the past few weeks has caused considerable damage and raised the alarm about the need for improved flood-control systems.

In just one hour on the afternoon of July 23, about 100 mm of rain fell on the Tokyo wards of Setagaya and Meguro. A thunderstorm Saturday washed out the annual fireworks display on the Sumida River.

In Yamaguchi Prefecture, a 79-year-old woman was found dead after a mudslide knocked down her house Sunday amid record rainfall.