Authorities in the earthquake-hit county of Yingjiang in Southwest China's Yunnan Province are racing against the clock to fix cracked dykes before the May flood season arrives so they could keep tens of thousands of people out of danger.

A survivor of the Yingjiang earthquake listens to the radio to learn about rescue efforts.

Thursday's 5.8-magnitude earthquake, which left 25 dead and hundreds more injured, severely damaged local dykes. Some and 40 kilometers of dykes showed cracks, China National Radio reported on Sunday.

The crack on some sections extended to 30 meters, the report said.

"We might have to use cement to repair the most damaged dykes and by building external walls," Yan Xinyuan, the director of Bureau of Water Resources of Yingjiang, told the Global Times on Sunday.

An estimated 30,000 to 40,000 people could be at risk if the flood season arrives before the problem is fixed, said Zuo Qiangguo, a county spokesman.

The search for survivors ended Saturday, the Xinhua News Agency said, adding that efforts are being focused on survivors and cleaning up.

"We are checking and tearing down damaged buildings that could pose hidden risks, before we use the allotted of 50 million yuan ($7.6 million) from the central government to start reconstruction. Power supply has been available to most of the county and some schools will reopen tomorrow," Zuo said.

Feng Yingxi, the headmaster at the No. 1 High School, said most of his colleagues have lived in tents on their campus since Friday. The school with more than 2,200 students lost no one during the earthquake and teachers will return to the classroom on Tuesday.

"Aftershocks happened from time to time during the past days but most of us tried to keep our composure composed," Feng told the Global Times yesterday. "Some supermarkets have raised their food prices but most have not."

Yingjiang residents are no strangers to earthquakes. During the past two months, the county has experienced some 1,200 earthquakes measuring 5.0 or under, according to Xinhua.