3 June 2008
Tangjiashan – CCTV footage of the channel
Posted by Dave Petley
There is a very good film (in Chinese) of the Tangjiashan landslide. It is available at:
http://video.sina.com.cn/news/c/v/2008-06-03/084017059.shtml
The first 6 minutes or so are worth a look. Early in the video they fly a helicopter over Beichuan, which shows the damage caused by landslides there. They then land the helicopter on the landslide mass and the reporter goes into the channel. It appears to be about 5 m wide at the base with steep walls. The material is silt by the look of it, with just a few clasts.
The Chinese goivernment has done a fine job to build a channel at all, but this is not going to be able to contain the flow.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
Dear Dave:Thanks Dave, very good film.According to vedio, two seepage point was happened, one is at El. 700 m, another at El. 660 m which may be the bottom. Indeed, 10 cms is very large rom seepage point of view.From current information, I guess that the strategy of Chinese government is following: reduce storage volume from 320 million to 200 million, second is increase overflow capacity by using this emergency spillway which very much depends on the incoming flow condition and resistance of channel. The best condition is gradually erosion of spillway and release the storage of water. The worst condition is dambreak.