Experts say that some barrier lakes formed during last month's earthquake are under greater danger of bursting their banks, and many uncertainties remain affecting the outcome.

Experts and relief workers are closely watching the lakes. Our reporter Liao Jibo has more.

Reporter:

The Tangjiashan lake in Mianyang city is the largest and most dangerous barrier lake that was formed when the nearby river was blocked by rocks and mud that fell from the mountains during the earthquake.

Liu Ning, a chief engineer with the Ministry of Water Resources, says the water level at the Tangjiashan barrier lake in Sichuan is very high and there is a great possibility of the lake water threatening the lower regions.

The water level reached 737 meters on Tuesday, less than 2 meters from the lowest point of the containing bank.

Liu Ning says in addition to the high water level, the loose structure of the barrier and more rain also make the situation dangerous.

''It is still hard for us to analyze the structure of the rocks and mud that are forming the lake. Also, the weather here is continuously changing, so it's difficult to predict when additional rain will arrive.''

The engineer adds that the weak points around the lake where a collapse might take place have not all been discovered, intensifying the danger.

In order to better monitor the situation at the barrier lake, related departments have set up 13 long-distance video monitors in the lake area.

Du Houqi, the director of the Mianyang Water Resources Bureau, says the cameras can send real-time video of the lake.

''The video monitors help us to observe how the lake is draining, and help us to determine the strength of the dams.''
The Xiaojiaqiao Barrier Lake, another one in Mianyang city, is also threatening to burst its banks.

The Chief Engineer with the Sichuan Water Resources Bureau, Wang Huide, says rescuers have been digging a diversion channel to drain it for about ten days.

''Our construction is fully meeting the design standards. Now we are widening the channel and making it deeper. We are working in shifts to make sure that the work continues 24 hours a day.''

Mianyang was one of the hardest-hit regions by last month's earthquake in Sichuan Province. At least three barrier lakes have been formed in the city suburbs so far, and the local government has evacuated a large number of residents to safer areas, for fear that the water may burst the banks of the barrier lakes.

Liao Jibo, CRI news.