Wu, ordinarily a chef for his division under the APHF, has been braving heavy rain and extreme heat to fix embankments in Jiangxi, which has experienced 31 downpours since early June.

"When the sky clears, it gets very hot and it's easy to get sunburnt while working," said Wu, 23. "All the soldiers' skin has turned very, very dark."

Wu's arms are a bizarre red and peeling. His feet have also blistered because they are constantly submerged in water. But Wu said he has become used to it.

"I put saving people's lives first," he added.

So far, the floods have swept away three dams and an embankment in Jiangxi, with more than 4 million people threatened. Four people have been killed and another remains missing. More than 300,000 hectares of crops have been damaged and 4,252 houses toppled, leading to a direct economic loss of 6.2 billion yuan ($928 million), according to government figures.

Under such circumstances, local officials and residents have all been urged to join the battle.

In Jiangxi's Pengze County, official and elementary school teacher Yang Kai has spent the past four days patrolling an embankment, inspecting it for seepage. Many of the houses in his village have already been flooded with water from Poyang Lake.

Yang is particularly concerned about "piping," the destabilizing effect that occurs when water penetrates an embankment, potentially causing full-scale leakage, a landslide or even endangering the whole embankment.

"What we do is check if there is any muddy water alongside the embankment," he said. "If we find any signs of seepage, we put a red banner or plastic bag at the spot so that soldiers will come and fix it."

It is no easy job. Working in groups of three, officials like Yang have to patrol the 2-km-long embankment for several hours a day.