Flood risk rises along rivers in quake-hit China (Roundup)

May 15, 2008, 12:36 GMT

Beijing - More than 500 reservoirs were damaged by Monday's devastating earthquake in south-western China, posing a flood risk to several towns and cities, the government said on Thursday, prompting troops to evacuate as many people as possible from one town close to the epicentre of the quake.

A lake had formed on the Bai He river upstream from Beichuan town after a landslide caused by the earthquake blocked the river, an official from the Sichuan Seismological Bureau told Deutsche Presse-Agentur dpa by telephone.

Because of the high risk of flooding, troops evacuated everyone to higher ground before returning to continue their rescue work in Beichuan, which was home to about 30,000 people, state media said.

The Sichuan official declined to respond when asked how the government planned to tackle the blockage on the Bai He.

Officials estimated that up to 5,000 died in Beichuan, where about 80 per cent of buildings collapsed in the old town and 60 per cent in the new town.

The troops had evacuated more than 10,000 people from Beichuan, state media said late Thursday, but they were continuing to dig through rubble in the hope of rescuing some of the thousands of people still missing in the town.

The water ministry reported that 391 reservoirs were damaged in Sichuan, including two large reservoirs, with 129 damaged in the neighbouring region of Chongqing.

Minister of Water Resources Chen Lei on Thursday said that quake damage to rivers, dams, reservoirs and hydropower plants posed a 'serious threat' of flooding in several areas of Sichuan and neighbouring provinces.

Most reservoirs in Sichuan had sustained 'significant but still unknown damage' during Monday's 7.8-magnitude quake, state media quoted Chen as saying.

'Inadequate management systems and poor data collection' meant that officials also did not know the full extent of damage to hydropower plants, the official Xinhua news agency quoted him as saying.

Flood control at damaged reservoirs, hydropower plants and dikes would be a crucial part of the government's relief work, aided by satellite imaging and aerial photography, he said.

More residents may have to be evacuated along other rivers with a high flood risk, Chen said.

But the water ministry deemed the Zipingpu dam, close to the quake epicentre in Sichuan's Wenchuan county, 'structurally stable and safe,' the agency said.

Workers and engineers had rushed to build a temporary outlet from the reservoir behind the dam on Wednesday, after quake damage caused a build-up of water, cracked the dam wall, and destroyed buildings at the Zipingpu hydropower plant.

'If Zipingpu develops a serious safety problem, it could bring disaster to Dujiangyan city,' where some 500,000 people live downstream along the Min River, the ministry said in a statement on its website on Wednesday.

Paratroopers who gave an initial report to state media on Wednesday from Sichuan's isolated Maoxian county said two more dams were at risk of breaking at hydropower stations that were 'severely damaged' in the quake.

But the famous Dujiangyan irrigation system, which dates back more than 2,000 years, was reported safe.

There was also no significant impact from the quake on the massive Three Gorges dam and hydropower plant along the Yangtze River, reports said.

Monday's earthquake killed more than 50,000 people, according to a government estimate announced late Thursday.