The possibility is growing of Tangjiashan barrier lake bursting. Authorities are considering the implementation of a drainage plan and the evacuation of more people from areas at risk.

The threat of floods from the barrier lake, formed by landslides after the May 12 earthquake, has been exacerbated by continuous heavy rain in the mountains upstream.

As of 2pm on Thursday, the water level was over 737 meters, with the lake holding over 217 million cubic meters of water. A video monitoring system has also shown water forcing its way out of the dam's base. With more rain forecast, the chief engineer of the Ministry of Water Resources, Liu Ning, has warned there is a 93 percent chance that the lake bursts its banks.

More than 600 armed police and soldiers raced against time to complete a drainage sluice last week, but it is still unclear when the draining of the lake will actually take place. Experts say it will be decided by the influx of water from upstream. 18 engineers and soldiers are staying in Tangjiashan to monitor the lake closely.

Wen Yong, Official of Mianyang City said "We have been briefing headquarters with the latest data. Though it is dangerous, we have drawn up an evacuation route, and once the danger is here, we will climb to higher lands and a helicopter will carry us to safety."

Further emergency plans have also started in Jiuling County downstream, as people began to evacuate on Thursday afternoon.

With the flood threat intensified in Tangjiashan, the biggest of 35 quake-formed lakes in the stricken areas, drainage work has gone smoothly in Xiaojiaqiao and Wenjiaba barrier lakes, and rescue efforts are still underway in other more dangerous ones.

(CCTV June 6, 2008)