China's Three Gorges Dam was tested for the second time this month Wednesday morning as the highest water flow of the year hurtled down the swollen Yangtze River.

A tourist watches Three Gorges Dam release water along the river in Yichang, Central China's Hubei province on July 27, 2010. [Asianewsphoto]

Flow rates as high as 56,000 cubic meters per second hit the dam at 8 a.m. Wednesday, dam engineers said.

The dam withstood the flow with a water discharge rate of 40,000 cubic meters per second, meaning 16,000 cubic meters of water per second accumulated in the reservoir behind the dam.

The water level in the reservoir had risen to 158 meters at 8 a.m. Wednesday, about 17 meters below its maximum capacity of 175 meters.

Continuous downpours in recent weeks have raised water levels in the upper reaches of the Yangtze.

Water flows on the river's upper reaches reached 70,000 cubic meters per second on July 20 -- the highest level since the dam was completed last year and 20,000 cubic meters more than the flow during the 1998 floods that killed 4,150 people.

Vessels' transit through the dam resumed last Thursday after the first peak flow passed. But it was suspended again at 10 p.m. Tuesday as the second round of floodwaters approached.

After the shipping service was suspended, a road near the dam was opened for vehicles to transport goods and people across the dam.