A group of 105 armed police officers and soldiers were dispatched to southwest China on Tuesday to help drain a swelling earthquake-induced lake at risk of bursting and threatening thousands of people downstream.

Diggers use excavators and bulldozers to dig a diversion channel for a quake lake at Tangjiashan, Beichuan County on May 26, 2008. The lake was formed by landslides that blocked a river known as the Jianhe after the May 12 earthquake in Sichuan Province.Helicopters have airlifted professionals and materials for the operation to the area Monday afternoon. [Xinhua]

The contingent from the No.2 Hydropower General Detachment of the Armed Police Force, in Nanchang, Jiangxi Province, will arrive in Chengdu, capital of Sichuan, at 2 p.m. on Wednesday and will be flown to Tangjiashan Lake, formed by landslides that blocked a river known as the Jianjiang after the May 12 earthquake.

They will join 600 rescuers, consisting of armed police and other professionals at the blockage site to help build a 200-meter-long sluice to drain the swelling lake.

Tangjiashan, one of 35 such lakes, is inaccessible by road and can only be reached by foot or air.

It currently held 130 million cubic meters of water, said Liu Ning, Ministry of Water Resources chief engineer, who is at Tangjiashan to oversee the work. Its water level was 725.3 meters on Monday, only 26 meters below the lowest part of the barrier.

Li Huzhang, an engineer with the armed police, said three emergency plans had been drawn up to dig the sluice. At least 50,000 cubic meters of debris would have to be removed. Rescuers, however, were aiming to remove 100,000 cubic meters of debris if the weather allowed.

The water level in the lake rose by 1.6 meters on Monday, a slower rate than recent days, a hydrological expert was quoted as saying by the People's Daily Online.

As of 9 p.m. on Monday, around 600 engineers and soldiers had gathered at the site, in Beichuan County, the area worst hit in the devastating May 12 quake, and were working in shifts through the night.

Helicopters had airlifted in professionals and materials for the operation.

A Mi-26 helicopter transported 15 diggers, bulldozers and dump trucks to Tangjiashan on Monday. By 7 p.m. on Monday, more than 40 tons of relief materials, including tents, drinking water, food and gasoline, had been airlifted to the site.

But experts said more machinery was needed because of the size of the blockage and the constant accumulation of debris because of continuous aftershocks. On Sunday, the area was affected by a strong tremor measuring 6.4 on the Richter scale.

Another contingent of armed police arrived on foot early on Monday. They were part of the 1,800-strong force, including People's Liberation Army (PLA) personnel, who started hiking on Sunday towards the lake, 3.2 km upstream from the Beichuan County seat, from which thousands of quake survivors have been evacuated since last Wednesday.

Altogether, 35 barrier lakes were formed by landslides after the quake that left 65,080 people dead and 23,150 others missing as of Monday noon, according to the Information Office of the State Council.

(Xinhua News Agency May 27, 2008)