A bus is trapped on a flooded street in Chizhou in east China's Anhui province on Tuesday. (Guo Chen/Associated Press/Xinhua)

Workers raced to build waterways to drain overflowing reservoirs in southeastern China and thousands were evacuated following torrential rains that triggered flash floods Wednesday.

Heavy rains overwhelmed three reservoirs in Poyang county in northern Jiangxi province, forcing the evacuation of more than 10,000 people, the official Xinhua News Agency reported.

Torrential storms have pelted the Yangtze River basin this week — including parts of Sichuan, Jiangsu, Zhejiang, Jiangxi and Anhui provinces.

In western China, the death toll from landslides triggered by heavy rains rose to 37, with another 37 people still missing, Xinhua reported.

In the worst-hit community of Xiaohe in Yunnan province, the death toll climbed to 13 following a landslide that swept through town before dawn Tuesday, Xinhua said.

Two landslides killed 14 in neighbouring Sichuan province while in Hunan province, 10 people including four young children died in two separate slides this week, the report said.

Meanwhile, the waters in a reservoir near the far western city of Golmud began to subside after hundreds of workers and soldiers finished digging a diversion channel, an official at the Qinghai province water bureau said.

Reservoirs swell beyond warning levels

More than 10,000 residents were evacuated as soldiers transported sandbags, rocks and dirt and used bulldozers to dig the emergency waterway, the Golmud city government website said.

Usually prone to drought, Qinghai has seen increasingly heavy rainfalls in recent years. This year's rains fell as snow melted in the surrounding mountains. Dozens of reservoirs swelled beyond their warning levels, the water bureau official said.

In the eastern province of Anhui, workers were draining overflowing reservoirs and repairing damaged dams, Xinhua reported.

About 70 per cent of the 282 reservoirs in Chizhou city have exceeded warning levels due to torrential rains.

Since the beginning of July, flooding across China has killed 107 people, with 59 missing and nearly a million people evacuated from their homes as of Tuesday, Xinhua said. More rain was expected to batter affected regions through Thursday.

Parts of China experience annual flooding but this year's rains have been particularly devastating. Storms so far this month have caused economic losses of $2.9 billion US, according to the Ministry of Civil Affairs.