Tangjiashan quake lake in Sichuan province of China continues to be a threat to the 1. 3 million people with an alarming rise in its water levels.
It was formed when landslides affected by the May 12 earthquake obstructed the flow of the Jianjiang River.
Meanwhile, rescue workers including soldiers and engineers managed to complete the widening and deepening of the drainage channel.
Military engineers fired missiles to blast the boulders in the channel to increase the flow of water from the lake early on Saturday, China daily reported.
But the drainage plus natural leakage from the lake is about 25 cu m per second, while the inflow is 4.6 times greater, informed Zhang Ting, head of the Sichuan provincial hydro-meteorological bureau.
The outflow of the water has to be increased otherwise the inflow will increase the pressure on the dam, but greater volume of outflow can erode the diversion channel and cause the dam to collapse. moderate rainfall around 6:50 p.m. shortly followed by a 4.8 magnitude aftershock caused massive landslides on the surrounding mountains, Xinhua reported.
Though the after effects are being looked into, there was no apparent change in the flow of water.
About 600 armed policemen and soldiers have dug two channels to divert the water and are working on a third, for which about 60,000 cu m of earth and boulders will have to be cleared, said Liu Yongjian, a People's Liberation Army (PLA )officer, in charge of the channel work.
"We have made preparations to trigger underwater blasts too, to make the channels deeper so that more water can flow out," Liu said.