By Wu Jiao in Beijing and Fu Jing in Deyang (China Daily)
Updated: 2008-05-26 07:29

About 1,800 military personnel were last night trekking toward an expanding quake lake near worst-hit Beichuan county, hoping to blast away its landslide barrier before it bursts and causes a flood.

The Tangjiashan quake lake, 3.2 km upstream from the devastated Beichuan county seat, was formed because massive landslides partially blocked the Qianjiang River.

Its barrier is in danger of bursting as the water level rose by nearly 2 m on Saturday to 723 m, only 29 m below the lowest part of the barrier. The coverage of the lake has reached 3,550 sq km, a size of a mid-sized city, according to the latest figures.

"Each of the team has 10 kg of dynamite, and they are expected to arrive at the site tonight," a PLA spokesman told Xinhua Sunday.

Earlier attempts to send military helicopters on the same mission were hampered by adverse weather and low visibility at the Tangjiashan lake site.

Yesterday, the PLA soldiers were trying to reach the lake through mountain paths or on boats after the transport network collapsed after the May 12 quake.

The local meteorological bureau forecast high winds and thunderstorms Sunday and today for the area.

More than 20,000 people downstream have been evacuated, officials said.

"They are safe but urgently need tents," Liu Tangyun, an official with the anti-flood and drought headquarters of Jiangyou city where about 20,000 residents were evacuated by noon on Saturday, told China Daily.

Liu said the government had sent emergency teams to prevent residents from returning to their homes.

The Tangjiashan quake lake is one of the 35 large-scale quake lakes formed after the May 12 earthquake, aftershocks and landslides that jolted southwest China.

Thirty-four of them are in Sichuan, posing a new danger to more than 700,000 of the people who survived the deadly quake, Vice-Minister of Water Resources E Jingping said in Beijing Sunday.

Though three of them have burst, all are "under control", the vice-minister said Sunday.

But heavy rains forecast for the area over the next three days are a major threat, as the water build-up in the lakes could cause the landslide barriers that formed them to burst and flood nearby areas, E told a news conference held by the State Council Information Office.

Workers also plan to dig tunnels to drain water from dozens of other unstable lakes except in Tangjiashan. The government fears that as water levels rise, they could burst, drowning survivors and rescue workers downstream.

At an emergency meeting Sunday in Chengdu, the Sichuan capital, Vice-Premier Hui Liangyu ordered rescuers to eliminate the risk "with utmost effort and within the shortest possible time".

The Ministry of Water Resources has drawn up evacuation plans for communities downstream of the 19 quake lakes at a higher risk of bursting, E said.

Another 310 reservoirs were in a "highly dangerous" situation and more than 1,400 posed a moderate risk, E said.

Xinhua contributed to the story