Engineers relieve stress on 'quake lake'

BEIJING, China (CNN) - Engineers significantly relieved pressure on an earthquake-created dam in southwestern China, state media reported. But the progress came at the expense of flooding downstream, according to China's Xinhua news agency. The volume of water behind the dam has been reduced by more than a third in the last day.

Authorities in Sichuan province had been concerned that the Tongkou River would top the dam unless they could increase the drainage rate from the vast lake forming behind it. Three spillways created by engineers over the last several weeks boosted the outflow so that it greatly exceeds the amount of water coming in, Xinhua reported.

The so-called Tangjiashan quake lake formed after last month's devastating magnitude 7.9 quake. Tons of rock and soil slid off a hillside, blocking the river.

The increased drainage pushed the Tongkou out of its banks, but officials hoped relatively minor flooding now would prevent a catastrophic flood later on, if the dam were to collapse.