No casualties had been reported in the villages in Liuhuang Town, said Guo Chunshan, the town's Party chief.
"All the evacuated residents have been appropriately resettled," said Guo, adding more people would be relocated if necessary.
The level of Hanjiang River, the second largest in Guangdong after the Pearl River, had dropped nine-tenths of a meter since a sluice gate was opened at 4:00 AM on Monday, but it was still 3.5 meters higher than the danger level, according to the food control office of Fengshun County.
The level of Hanjiang River, which runs 400 kilometers in east Guangdong, had risen since continuous heavy rainstorms hit the county on Friday.
By 4:00 AM on Monday, the level reached 26.44 meters, the highest in 50 years, threatening at least 2.5 million people along the middle and lower reaches.
"Actually, landslides and collapses have been frequent along the river dam area," said Guo. "If we hadn't opened the discharge gate, the dam might have overflowed and the losses would have been much more serious."
The village of Huanshi was almost completely submerged after the diversion. Most of the buildings are inundated up to the tops of the doors and villagers were piling their belongings on bamboo rafts.
"My house has been totally submerged and my whole family is staying with relatives," villager Zhan Meizhi told Xinhua.
"I don't know when we can return home, but village officials told us the government would take care of us and we could get compensation," said Zhan.
The local government organized more than 500 police and army personnel to help the evacuation and rescuers distributed drinking water and food.
According to the provincial observatory, more rains will hit the southwestern and eastern part of Guangdong from Tuesday to Thursday. Local governments have been warned to prepare for more floods.
According to the Ministry of Civil Affairs, rainstorms in south China since the beginning of June had left 71 people dead and affected more than 10.63 million people by Monday.
In Guangdong alone, at least 20 people were killed, 279 injured and four are missing, according to the ministry's latest report.
The province's economic losses stand at 1.25 billion yuan (US$160 million), more than one third of the total losses from disasters, according to the ministry.
The ministry has sent rescue teams to the disaster-affected areas to assist relief work.