17 July 2013
China continues to receive very heavy rainfall across a large part of its territory, triggering widespread landslides and floods, with Sichuan Province currently representing the epicentere of the affected regions. Indeed, although the monsoon season has two months to run, the impacts are already proving to be very serious. The first belt of rain affected Sichuan Province a week or so ago, triggering the very large landslide at Sanxi in Dujiangyan City. This landslide, which received a surprisingly low level of interest outside China, is now thought to have killed 161 people, of which 44 bodies have been recovered to date. Elsewhere across Sichuan the rains killed another 14 people, with a further 58 people missing, and 13,400 houses destroyed.
One of the impacts of the rains has been the formation of a landslide dam and associated lake at Sanjiao Township, Hanyuan County, 3 km from a hydropower construction site. It is not clear as to which HEP station this is referring. Google Earth has an image from March 2013 that shows a small , if slightly unusual HEP scheme at a place called Sanjiaoxiang, on the Lishui River, so I assume that it is this one:
If this is the right location, then the landslide is somewhere in this area:
A rainstorm-triggered landslide blocked the local Liusha River, forming the lake whose water level has reached about 40 meters, said a publicity official of Hanyuan. The blocking rocks are about 600,000 cubic meters in volume and the water in the lake is about 2 million cubic meters. The water level is expected to rise with the flood upstream. The lake is putting seven townships downstream in danger as water has been flowing out from the top of the landslide block.
Of course the Chinese are the world experts in dealing with barrier lakes, so I am sure that this will be mitigated successfully. A further major landslide impact has occurred in Shaanxi Province, where a landslide cracked an oil pipeline at Zichang County in Yan’an City Monday morning, resulting in a release of crude oil into the Haojiachuan River. And the BBC reports that in Guizhou province a landslide killed five people yesterday.
Unfortunately in terms of landslides across the region, further heavy rainfall is forecast for the Sichuan area over the next few days, with up to 300 mm forecast for the next 48 hours.