Nearly all of the remaining group of soldiers and engineers in the Tangjiashan barrier lake area were evacuated by helicopter by Sunday afternoon. Only a few of them are staying at the site to monitor the situation. Experts predict the lake will overflow its banks on Tuesday, if there is no precipitation on Monday.

The major project of a sluice -- an irregular cube designed to discharge flooded water -- from the Tangjiashan Lake is completed at quake-induced Tangjiashan Lake in southwest China's Sichuan Province, May 31, 2008. The first group of 15 earthquake relief workers handling the Tangjiashan quake-formed lake in China's Sichuan Province boarded a helicopter at 8:35 a.m. Saturday and were evacuated from the dam site.(Xinhua Photo)

Helicopters carrying the last major group of 620 soldiers and engineers are heading to Mianyang city. By 6 pm on Sunday afternoon, there were only 20 soldiers and experts left on the upper banks of the barrier lake. Experts have set up a monitoring network covering over 3,500 square kilometers of the lake's upstream area.

12 monitoring stations have been set up to collect information about precipitation, water level variations and meteorological conditions.

The diversion project to drain quake-formed Tangjiashan Lake was completed late on Saturday.

The evacuees, mainly members of the water and electricity section of the People's Armed Police Force, prepare to board on the helicopter at the dam site of quake-induced Tangjiashan Lake in southwest China's Sichuan Province, May 31, 2008. The first group of 15 earthquake relief workers handling the Tangjiashan quake-formed lake in China's Sichuan Province boarded a helicopter at 8:35 a.m. Saturday and were evacuated from the dam site. (Xinhua Photo)