Torrential rain in the upper stream of the Yangtze River, China's longest waterway, has caused this year's biggest flood crest, water conservancy specialists in the central Hubei Province said Tuesday.

People are evacuated in Pingchang County, Sichuan Province, on Sept. 18, 2011. Rain-triggered floods and landslides had left at least 57 people dead and 29 missing in China.?[Xinhua]?

Torrential rain in the drainage of the Jialing River, a major Yangtze tributary, caused flood water to gush into the Yangtze Three Gorges Dam Reservoir at an estimated 40,000 cubic meters per second Tuesday, at least twice Monday's volume, according to a hydrological report provided by the Three Gorges Navigation Authority.

It said the crest of the flood is expected to arrive at the Three Gorges Dam at 8 p.m., gushing at 45,000 cubic meters per second.

The water level in the Three Gorges Dam reservoir topped 160 meters Monday night, 16 meters above the alert level, it said.

On Monday, the dam began unleashing 21,000 cubic meters of flood water per second to the downstream regions for safety considerations.

The flood has not hindered water traffic in the Three Gorges Dam area, but in Hanjiang, Yangtze's largest tributary, traffic was suspended Tuesday for reasons of safety.

At least 1,672 vessels were called off the middle and lower streams of the Hanjiang River, the Hubei provincial flood control office said.

The State Flood Control and Drought Relief Headquarters issued flood alarms Monday night. It said persistent rains since Sept. 16 had swept the basins of the Han, Wei and Jialingjiang rivers, leading to floods in 14 rivers and tributaries of the Yangtze and Yellow rivers.

The flood has battered several provinces including Hubei, Shaanxi and Sichuan.