More than 100,000 residents are suffering drinking water shortages around the Poyang Lake, China's largest freshwater lake, as drought strikes. An expert has warned that the condition may blight the area for a further 10 winters, a direct result of climate change.

"The lake now covers less than 50 square kilometers, down from about 3,000 square kilometers in summer this year. The water surface was 300 to 500 square kilometers last winter," said Tan Guoliang, director of the Hydrological Bureau in east China's Jiangxi Province.

"My house used to be by the side of the lake. Now I have to go over a dozen kilometers away to get to the lake water. We have been used to the seasonal variations of the lake, but we have never been badly short of drinking water supply before," said Yu Wenchang, a villager living in the northeastern part of the lake.

Some 1,000 villagers in Yu's village of Xiayangzui in Changdu County of Jiangxi now live on water from four wells.

"A total of 52 of the 56 wells in the village have dried up, as the lake water retreats. Only four have water. Senior citizens told us that they had never seen the lake reduced so drastically in winter," Yu said.

Villagers have channelled water from a nearby pond to the dry wells, and they are preparing to dig deeper for water.

Many villagers have abandoned the use of boats since they can walk across the marsh of the exposed lake bed.

Jiang Tong, an expert with the Nanjing Institute of Geography and Limnology under the Chinese Academy of Sciences said that the Poyang Lake's winter drought is likely to continue for the next 10 years.

"Both the streamflows into the river and the Yangtze River water to replenish the lake will be insufficient in dry seasons in the future, because of climate change and the exploitation of water resources," said Jiang, who is a specialist in seasonal water responses to climate and land changes in Poyang Lake Basin.

Jiang said that the size of the lake depends largely on the rise and fall of the Yangtze River. The lake's drought is a signal showing the climate change in the Yangtze reaches.

Poyang Lake receives water from five rivers and discharges into the Yangtze, China's longest river. The Yangtze River basin, however, has suffered its most severe drought in half a century.

The lack of rainfall along the upper reaches of the Yangtze reduced water levels in the middle and lower reaches by 1.5 meters on average, the Yangtze River Maritime Administration said earlier.

The hydrological bureau's monitoring revealed that for the last two weeks the inflow from the five rivers feeding the lake was half of the amount that drained from the lake to the Yangtze.

Tan, the bureau head said that the river has been contributing water at 500 cubic meters per second to the lake since the beginning of this month, less than half of the average in the same period normally. Meanwhile, water draining out of the lake into the Yangtze at the rate of 924 cubic meters per second.

Rainfall has been unusually low: the provincial average of only 38 millimeters of rainfall from mid-September to early December is the lowest amount for this period since 1960, according to the Jiangxi provincial meteorological department.

"Jiangxi has received meager rainfall to replenish the lake," said Zhu Shuigui, head of the Jiangxi Provincial Headquarters of Flood Control and Drought Relief.

He said that the lake's water inflow normally rises in April and May after the winter drought, which is followed by a rainy season of several months, when the lake begins to swell.

"The drought might last through the winter, when there is normally no effective rainfall," said Zhu.

He said that an effective measure to ensure water supply for residents affected by drought was to dig more wells.

"We encourage the people to dig wells by providing 1,500 yuan (US$202) in compensation for each well they dig," said Tan.

The State Flood Control and Drought Relief Headquarters said earlier this month that drought has been afflicting more areas of the country with greater frequency recently. It had extended from the north and western regions to the south and eastern areas.

The Ministry of Finance has prepared 70 million yuan (US$9.46 million) in appropriations to support relief programs in the worst drought-stricken provinces of Jiangxi, Hunan, Hubei, Guangdong and Guizhou and in Guangxi Zhuang Autonomous Region.

Wu Xinxiong, governor of Jiangxi on Thursday urged local authorities to make anti-drought work a priority.

Poyang's water area of 3,000 sq km in July this year was still the largest in China, compared with the 2,360 sq km of the Dongting Lake, the country's second biggest body of freshwater, according to a satellite remote-sensing survey by the Hubei Provincial Observatory. Dongting is also located in the Yangtze River reaches.

(China Daily December 15, 2007)