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Water projects stand test of strongest floods in 20 years

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The Three Gorges Dam in Yichang, Hubei province, discharges excess floodwater on Monday. The dam has played a key role in flood relief efforts in the middle and lower reaches of the Yangtze River.

China DailyUpdated: July 28, 2020

Aerial photo taken on July 27, 2020 shows floodwater being discharged from the Three Gorges Dam in Central China's Hubei province. [Photo/Xinhua]

That helped keep the highest water level at the Hukou station to 22.49 meters, 1 centimeter lower than the maximum design level for dike safety and 10 centimeters lower than the record high, even as some stations at the lake hit historic highs. Without the help of those reservoirs, the pressure on flood control around Poyang Lake would have been massive, he said.

"The Three Gorges Dam played a marked role," Chen Guiya said.

He said the help the Three Gorges Dam provided to Poyang Lake was not as notable as that to Dongting Lake because more water entered the mainstream of the Yangtze from its tributaries as the river flowed eastward. Meanwhile, Poyang Lake also got a lot of water from rivers in its own basin. On July 11, for example, over 45,000 cubic meters of water entered the lake each second.

Aerial photo taken on July 27, 2020 shows floodwater being discharged from the Three Gorges Dam in Central China's Hubei province. [Photo/Xinhua]

Since June, the Yangtze basin has been hit by six episodes of torrential rain with hardly a break. The precipitation in the mainstream of the Yangtze's middle reach and the northern parts of the Poyang Lake basin was more than double the annual average, said Hu Xiangyang, director-general of the commission's Flood and Drought Prevention Bureau.

The rain has gotten heavier this month, with precipitation in the Poyang basin early this month three times the annual average, he said at a news conference on July 20.

The National Meteorological Center said that from June 1 to July 9, the average precipitation in the Yangtze basin reached 369.9 millimeters, the highest in the same period since 1961, and 54.8 mm more than the same period in 1998.

Despite historic precipitation, Chen Jionghong said he is confident the commission is capable of tackling the situation through key reservoirs.

As of July 21, reservoirs in the upper and middle reaches of the Yangtze had helped store 24 billion cubic meters of floodwater, with half of that amount held back by the Three Gorges Dam.

The available floodwater storage capacity of all the key reservoirs stands at about 33 billion cubic meters, Chen Jionghong said.

"We still have capacity large enough to prevent major floods," he said. "The public don't need to worry. We are capable of coping with the situation this year."

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