Authorities have called for tighter control of boats and small ships on the Yangtze River to ease river traffic congestion at the Three Gorges Dam, which is about to face the largest flood peak of the year this week.

In a joint statement, the State Flood Control and Drought Relief Headquarters and the Ministry of Transport called on local authorities to try to dissuade owners of boats and small ships from operating during the flood peak period and to tighten safety measures of vessels crowded at the dam.

The Three Gorges Dam will face the largest flood peak this year before dawn on Wednesday after heavy rains hit upstream areas of the Yangtze River, the national flood control authority said.

The flow rate could also be the highest at the dam since it began operation, the authority said.

Soldiers in Chongqing use a makeshift raft to evacuate people after heavy rain lashed the city over the weekend. More rain alerts have been issued for South China. [Photo/Xinhua]

The dam increased its floodwater release from 38,000 cubic meters per second to 43,000 cu m per second between Monday evening and Tuesday morning.

Authorities have promised to improve the efficiency of ferry services at the dam as soon as the amount of floodwater release is lowered.

Shipping congestion at the Three Gorges Dam has occurred since late June as the flood peak approached.

As of July 13, there were 606 ships were caught in the river traffic at the dam.

The congestion has already affected river cruises that operate between Chongqing and the dam.

"We have to cancel the tour to the ship locks because of the congestion," said a staff member of Chongqing Tourism Investment Group named Jiang. His group operates river cruises along the Yangtze.

Jiang said the congestion has increased the company's operating costs because it has to disembark the passengers at Yichang, Hubei province, and then use buses.

Torrential rain has ravaged 17 of China's provinces since July 20, leaving 95 dead and 45 missing, the Ministry of Civil Affairs said on Monday, Xinhua News Agency reported.

Natural disasters caused by the downpours have affected 6.23 million people in 264 counties and 17 provinces and municipalities such as Beijing, Hebei, Shanxi, Sichuan, and Guizhou, and forced the evacuation of 567,000 residents, the ministry said in a statement.

The ministry reported 37 deaths in Beijing, 17 deaths and 21 missing in Hebei, eight deaths and two missing in Sichuan, six deaths and four missing in Yunnan, five deaths in Chongqing, four deaths and one missing in Shanxi, three deaths in the Inner Mongolia autonomous region, and three deaths and 14 missing in Shaanxi.

Rainstorms have destroyed 29,000 houses and damaged another 55,000.

National disaster relief and civil affairs authorities initiated a level-four emergency response and sent teams to the worst-affected areas of Beijing and Hebei on Sunday to direct relief work.

As of Monday noon, natural disasters — strong wind, hail, floods, landslides and mudslides — had affected 110 million people on the Chinese mainland this year, leaving 680 dead and 137 missing, according to the ministry.

Jin Zhu contributed to this story.

xuwei@chinadaily.com.cn