Photo/IllutrationResidents living near the Sagamigawa river had evacuated to the Atsugi Junior High School gymnasium in Atsugi, Kanagawa Prefecture, at 6:05 p.m. on Oct. 12. (Shin Toyohira)

Fears of widespread dam collapses during the record rainfall from Typhoon No. 19 on Oct. 12 forced officials to order emergency discharges of water as reservoirs swelled in areas from the Kanto to the Chubu regions.

Residents living downstream of dams in five prefectures were alerted to the releases.

A Ministry of Land, Infrastructure, Transport and Tourism official said that it is extremely rare for water discharges to be considered or conducted on such a large scale.

“We had a lot of discussions inside the organization, but decided to do it in the end,” said a Kanagawa Prefecture official.

Dangers posed by emergency releases of water from dams is that areas downstream could be flooded if they are not protected by sturdy embankments.

After an emergency discharge of water was conducted from a dam in Ehime Prefecture during heavy rains that hit western Japan last year, the river overflowed its banks downstream, killing nine people in the flooding.

During Typhoon No. 19, water was released in at least seven dams in five prefectures.

Kanagawa Prefecture started the emergency discharge of water from the Shiroyama Dam, situated upstream of the Sagamigawa river in the prefecture, at 9:30 p.m. on Oct. 12.

Downstream, there are many cities whose population numbers around 200,000, including Atsugi.

At the Atsugi Junior High School gymnasium in Atsugi, Kanagawa Prefecture, situated near the Sagamigawa river, residents evacuated one after another after it was announced that there would be an emergency water release from the dam.

A 41-year-old female part-time worker evacuated with four family members. Her house is located near the point where the Sagamigawa and another river converge.

“After I saw the water level of the Sagamigawa river on the Internet, I felt it was very dangerous,” she said. “I am also worried about my home because of the strong wind.”

A emergency discharge of water also started from Miwa Dam, which is under the authority of the land ministry, on the Mibugawa river in Nagano Prefecture at 9:30 p.m.

Emergency releases of water were also ordered from Shiobara Dam in Tochigi Prefecture, Mizunuma and Ryujin dams in Ibaraki Prefecture, and Sugadaira Dam in Nagano Prefecture.

Tokyo officials ordered the release of a larger volume of water than anticipated from Ogouchi Dam, situated upstream of the Tamagawa river.

Evacuations were also ordered for residents who lived near rivers that could face flooding from the heavy rain brought by the typhoon.

Edogawa Ward in Tokyo is located between the Arakawa river and Edogawa river, and an estimated 70 percent of its area lies below sea level.

As of 9:45 a.m. on Oct. 12, an evacuation order was issued for 430,000 people. At one of the shelters, Hirai Elementary School, about 200 people at 4 p.m. on Oct. 12 were packed in, even occupying the hallways and staircase landing.

A 78-year-old man evacuated with his 79-year-old wife after being urged to do so in a phone call from their son, who lives in a remote area.

The couple remember Typhoon Kathleen in 1947. At that time, much of the areas in the ward were flooded, and a wooden boat had to be used to get around.

They were worried about the heavy rainfall amount, saying that they hoped that no damage would occur and they could go home soon.