Thirteen sluices at Wangjiaba, a key hydrological station, were closed almost two days after they were opened in a move to reserve capacity in flood zones, said an official from the Huaihe River Flood Control and Drought Relief Headquarters.

"We have received an order that when the water level with Wangjiaba falls back to or below 29.3 meters, the danger line, we should exercise restraint in diversion operations at Wangjiaba to reserve capacity in the Mengwa zone for bigger floods and to contain the losses from inundation inside Mengwa," said an official with the Administration for Wangjiaba Hydrological Station.

The sluices were closed at 9:52 a.m. Thursday after more than 45 hours operation. By 11:00 a.m., the water level recorded at Wangjiaba was at 29.3meters.

The Huaihe River originates from Mount Taibai, Henan Province, and runs eastward between the Yellow River and the Yangtze River, cutting through Henan and east China's Anhui and Jiangsu provinces before entering the Yangtze River via the Hongze Lake.

Concentrated and continuous rainfall has pushed up the Huaihe River, in its worst flooding since 1954.

The pressure on the embankments along both banks of the Huaihe River has been mounting, endangering the safety of key cities and railway lines on the middle and lower reaches of the river.

The sluices at Wangjiaba, in Anhui, were opened at 12:29 p.m. Tuesday to divert waters to the Mengwa buffer zone, home to 150,000 people.

The move should bring relief to more than 2 million flood-hit residents in Henan Province, on the upper reaches of the Huaihe River, and alleviate pressure downstream, said Qiu Ruitian, deputy director of the Office of the State Flood Control and Drought Relief Headquarters.

The opening of the sluices was estimated to have damaged up to 12,000 hectares of cropland inside the 180-square-kilometer Mengwa flood storage area. The impact on the residents was expected to be limited, said local authorities.

Created in 1953, the area contains four townships, where most of the residents live in homes built more than 31 meters above sea level.

The Anhui Provincial Flood Control and Drought Relief Headquarters was forced to put into use three minor flood diversion zones downstream of Wangjiaba on Wednesday morning and to open 14 sluices at Jiangtanghu to divert water on Wednesday afternoon.

Anhui flood control workers have been racing to open the embankment at the unpopulated Qiujiahu so that floodwaters could be diverted there.

The flooding on the Huaihe River has led to evacuation of almost half a million people from the projected path of floodwaters from the river. About 343,900 of the 488,800 relocated people came from Anhui Province and the rest from the provinces of Henan and Jiangsu.

The three provincial authorities have mobilized 511,000 people to patrol the Huaihe embankments and issue emergency warnings, according to information from the State Flood Control and Drought Relief Headquarters.

China's central government set aside 232 million yuan (31.35 million U.S. dollars) on Wednesday to finance the ongoing battle against floods in Anhui, Jiangsu, Henan, Hubei and Sichuan provinces.

Nationwide, more than 66.3 million Chinese have been affected by floods this summer, with 360 people killed and losses amounting to 24.3 billion yuan, the State Flood Control and Drought Relief Headquarters announced on Wednesday.