Fears were mounting Monday for the safety of more than a million people downstream from a “quake lake” in China as waters threatening to burst a dam of landslide rubble were rising faster than engineers could drain them.
Authorities are concerned the Jianjiang River will top the dam unless efforts to dig and blast out emergency draining channels can drastically decrease the water level.
But engineers also risk letting out too much water at one time, which could also trigger a collapse of the dam created by a 7.9 magnitude quake that devasted China’s Sichuan province.
“Increasing the outflow of water is critical for the dam’s safety,” said Zhang Ting, head of the Sichuan provincial hydro-meteorological bureau, the Xinhua news agency reported.
“If the water flows too slowly, the inflow will increase the pressure on the dam. But again, too voluminous an outflow can erode the diversion channel and cause the dam to collapse.”
Update: Also, from Reuters:
Chinese troops are carving a third drainage channel into the unstable dam holding back a big “quake lake”, as water levels rise and aftershocks send more debris tumbling into the water, state media reported on Monday.
Soldiers are also using short-range missiles and dynamite to blast apart boulders blocking the first channel, to speed up the flow of water, the official Xinhua agency said.
The BBC has posted photos of the clearance of the “quake lake.”
