Dams and Landslides

Landslides put lives at risk in Three Gorges area

Kelly Haggart

May 14, 2002

Heavy rain in the Three Gorges dam area this month has triggered half a dozen landslides that have put hundreds of lives at risk and heightened concern about the region’s geological instability.

The Hubei Daily (Hubei Ribao) reported May 11 that five separate landslides and rock falls in Zigui county, about 40 kilometres upstream of the dam, are threatening the safety of 384 people. A mud-rock flow in Badong county, about 30 km further upstream, is posing a danger to a compound where 360 people live, the newspaper said.

A large landslide in Xietan township in Zigui county developed into a flowing mass containing an estimated 400,000 cubic metres of mud and rock that has destroyed 1,200 metres of road, blocked two highways and threatened 19 households, the newspaper said.

In Guizhou, the old county seat of Zigui, 41 families are at risk from a landslide that is 180 metres long and 270 metres wide. A landslide measuring 700 metres by 80 metres occurred in the town of Guojiaba, while another large one in Shazhenzi is threatening 17 households. A rock fall in Yanglinqiao has put 12 families at risk, the newspaper said.

In a separate report the same day, the newspaper said an office and residential compound occupied by the local Communist Party committee in Badong county lies in the path of a mud-rock flow.

Two such flows occurred on the morning of May 6, the newspaper reported. One fell into a ditch, while the other, containing 2,700 cubic metres of rock and mud, still poses a threat to two residential buildings. The compound consists of seven buildings in all, where staff of the Party committee work and live with their families. All residents of one of the buildings have been moved to temporary accommodation, the newspaper said.

The compound was built on top of three different old landslides, which since 1994 have been unstable and begun to develop cracks, the newspaper said. The seven buildings themselves now have cracked walls, and their foundations are slowly sinking as a result of subsidence.

The newspaper quoted officials monitoring the situation as saying that the condition of the landslip masses and the wet weather were likely to reactivate the old landslides. Officials are working to move more people from the danger zone, the newspaper said.

The report does not make clear whether it is the old or the new county town of Badong that is under threat. In the mid-1990s, after millions of dollars were spent on the construction of buildings, roads and bridges in the new county seats of Badong and Fengjie, geological experts discovered that the two half-finished towns were being constructed on unstable ground. New sites had to be selected and the work started all over again.

The world’s biggest dam is being built in a geologically unstable area that is prone to landslides and earthquakes. A survey by the Changjiang Water Resources Commission last year identified 1,320 zones in the area that are at risk of landslides and mud-rock flows.

Two senior water engineers recently urged the Beijing government to undertake a geological safety inspection of all new settlements being built in the area before the Three Gorges dam reservoir is filled next year. They predicted that impounding a huge body of water in the 600-km-long reservoir is likely to activate at least 760 landslips.

Although many such events are never made public in China, the Chongqing Morning Post (Chongqing Chenbao) did report in early March that a huge landslide containing 20 million cubic metres of rock and earth was threatening the new town of Wushan, 125 kilometres upstream of the dam, putting more than 10,000 newly resettled migrants at risk. Xu Kaixiang, chief engineer of the Three Gorges geological disasters prevention headquarters, said at the time that construction work in the area had reactivated geological weaknesses that had caused landslips in the past.

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