The Yangtze River, China's longest, has been plagued by a severe drought, with the lowest level of rainfall this year since 1961, an official with the river's flood control and drought relief headquarters said Monday.

The spring drought has affected Jiangxi, Hunan and Hubei provinces in the middle and lower reaches of the Yangtze River, with forty to sixty percent less rainfall on average, said Wang Guosheng, chief director with the headquarters.

Some regions have been overwhelmed by the lingering drought, which has seriously affected irrigation and water supply, Wang said.

In spite of the increased rainfall that commenced in May, downstream provinces such as Hubei, Hunan, Jiangxi, Anhui and Jiangsu have received twenty to forty percent less of it.

During the January-April period, the Yangtze River basin received 40 percent less rainfall than the past 50-year average.

A survey conducted by the headquarters' hydrographic office predicts that during the flood period (May to October) the Yangtze River basin will receive a normal quantum of rainfall, though it will come at an uneven proportion.

The severe drought followed by heavier rains could lead to flooding in the river's upper stream, the report said.

"Even in a severe drought, we have to be alert on flood control along the Yangtze River," said Wang. "It remains a challenge to safeguard the region from flooding.

The Yangtze River basin extends over a vast territory along its length of 6,397 km, and the regions along it are frequently plagued by natural disasters.