At least 3,000 ship borne tourists to the Three Gorges have to switch to buses as flood from Yangtze's upper reaches closed down the Three Gorges ship lock on Monday, the local navigation bureau has said.

The Yangtze River Three Gorges Navigational Bureau halted two-way traffic at the Three Gorges ship lock at 8:00 a.m. as water influx into the dam measured an alarming 51,000 cubic meters per second, a result of continuous rainfall in the upper reaches, said Shi Huili, a traffic control officer with the bureau.

Wanzhou and Wushan in the Three Gorges Dam area received an average 100 mm of rainfall on Sunday, causing the water influx into the dam to soar to 46,000 cubic meters per second at 2:00 a.m. on Monday.

For safety considerations, the national bureau has to close down the ship lock when the water influx exceeds 45,000 cubic meters per second.

Shi said the traffic ban will last for about two days.

About 170 ships pass the ship lock every day, including at least 30 passenger ships carrying tourists to the world's biggest water control facility.

The lock, 6.4 km long and costing 6.2 billion yuan (775 million U.S. dollars), was built into the mountainous terrain on the northern bank of the Yangtze and has been the only navigable route past the dam since 2003.

Editor: Donald