Residents of Jingzhou, Hubei province, say Three Gorges Dam, which started to retain water in 2003, provides great protection from floods.

The city, about 220 km from Wuhan, the provincial capital, is traversed by the Jingjiang River, a section of the Yangtze River, and has been designated a flood control region.

Water cascades from six sluices at Three Gorges Dam on Friday after a flood with a peak flow of 55,500 cubic meters per second on Thursday night significantly raised the water level in the dam's reservoir. Zhai Pingguo / for China Daily

Tang Changsi, 36, who lives near the Jingjiang River, has been through several floods, including one that killed 1,432 people in 1998.

Tang recalled that he and many residents set aside their work that year to help the government monitor the flooding day and night.

"The water always made an awful sound," he said. "Everyone was nervous and had no idea when the city might be in danger."

Even though flooding still occurs along the Jingjiang, Three Gorges Dam has greatly reduced it, Tang said.

"I keep on living a normal life when flood season comes every year," he said on Friday, a day after floodwaters on the Yangtze River crested for a second time this year. "Without the dam, I would most likely be on the riverbanks fighting the flood right now."

From 8 pm on Wednesday to 8 pm on Thursday, water flow through Three Gorges Dam had increased from 48,000 cubic meters per second to 56,000 cu m per second, raising the water level in the dam's reservoir by 1.45 meters, according to China Three Gorges Corp.

With the dam holding back the floodwaters, the river was flowing at 30,000 cu m per second in Jingzhou, posing little danger to the city, said Zhang Genxi, a flood control official.

On Friday, more than 10 swimmers could be seen in the Jingjiang River.

Analysts compared Three Gorges Dam, the world's largest hydroelectric project, to a water faucet that can be turned on and off to control flooding and irrigation along the Yangtze River.

The dam began to store water in 2003, when the maximum water level in its reservoir was 135 meters, and it became fully operational in 2010, when the maximum level increased to 175 meters.

So far, the largest flood to hit Three Gorges Dam sent water through at a rate of 70,000 cu m per second in 2010, raising the water level in the reservoir to 161.01 meters, according to the Changjiang (Yangtze River) Water Resources Commission.

"The dam project, which was seen as a way to control flooding on the Yangtze River, has successfully withstood several huge floods in recent years," Wei Shanzhong, deputy director of the commission, said on Thursday.

Three Gorges Dam's 32 generators began to operate fully on Friday.

"Its total energy output is expected to reach 540 million kilowatt hours per day, generating 135 million yuan ($21 million) worth of electricity," a worker at the Three Gorges Hydropower Plant, who declined to give his name, said on Friday.

Enough water will flow through to enable the plant to generate that much energy for a day or two, he said.

Meanwhile, continuous flooding in the past two weeks has made parts of the Yangtze River near the dam unnavigable for more than 500 cargo ships, Wei said.

"Smaller ships have been ordered to anchor at locks as a safety precaution while the dam discharges large amounts of water at peak flood times," he said. "The heat is making that really hard, though, on the people onboard those ships."

Contact the writer at jinzhu@chinadaily.com.cn