Wednesday, September 21, 2011

Japanese Government warns of partial collapse of landslide dams in Nara, Wakayama prefectures - 21st Sept 2011

The government is calling for the Nara and Wakayama prefectural governments and local bodies to take precautions following signs that two landslide dams in the prefectures created by Typhoon No. 12 may have partially collapsed.

"It's possible there've been partial breaches or overflows," a representative of the Ministry of Land, Infrastructure, Transport and Tourism's Kinki Regional Development Bureau said. Collapse of the dams could lead to significant flooding.

One of the dams, located in Gojo, Nara Prefecture, has a maximum capacity of 550 cubic meters of water, making it the second-biggest of 17 landslide dams formed in the two prefectures. The water level had been steadily rising due to rain that fell from Sept. 20, and as of 10:10 a.m. on Sept. 21, the water level was 1.33 meters from the top of the dam. However, the water level then sank by 1.12 meters in one hour, suggesting part of the dam had collapsed.

Another dam in the Kumano district of Tanabe, Wakayama Prefecture, is believed to have overflowed on Sept. 20. Over a 1 1/2-hour period from 9:50 a.m. on Sept. 21, the water level fell by 42 centimeters. About one kilometer downstream from the dam, a sensor designed to warn of landslides was activated and a siren sounded. Officials said the water level in the river had risen but no landslides had been confirmed. Read More