|Xinhua Insight: Crisis grips China's largest freshwater lake|
NANCHANG, Nov. 13 (Xinhua) -- China's largest freshwater lake, Poyang, is surrounded by purplish-red flowers, with grazing sheep and picnickers enjoying lunch on its dry lake bed.
"I started herding my sheep to the lake in late September, a month earlier than I did several years ago," said Cheng Wenwei, a veteran shepherd living near Poyang in northern Jiangxi Province.
"That's because the lake water has started to ebb earlier," Cheng explained, while tending his 200-head flock.
In early November, Poyang was reduced to streams, with some parts of its vast lake bed becoming pasture or sand after the lake's annual dry season arrived on Oct. 19.
Data from the Jiangxi Provincial Hydrographic Bureau show that, between 2003 and 2013, the average date when the lake entered its dry season was Oct. 27, 52 days earlier than the average recorded between 1952 and 2002.
The lake's dry season is signaled when a benchmark hydrological spot, Xingzi Station, records water levels below 10 meters. The dry season normally ends in late March.
Due to the lake's prolonged dry seasons over the last decade, an escalating water shortage has caused drinking water scarcity, crippled the local fishing industry, and threatened the lake's ecology.
Fed by five major rivers in Jiangxi, Poyang is located in the middle and lower reaches of the Yangtze River, with the lake's discharges accounting for about 15 percent of the Yangtze's annual runoff.
DROUGHT AND DAMS
Experts and local officials believe persistent drought and a cluster of hydropower dams on the Yangtze are two primary contributors to the lake's water crisis, in addition to increasing water use and damages to the lake bed.
In recent years, the lake has seen dwindling precipitation during its dry season, caused by increasingly uneven distribution of rain, which has made dry days even drier, said Tan Guoliang, director of the hydrographic bureau.
Meteorological data showed the province has received 60 percent less precipitation since September than the average over the same period since records began in 1952.
A lack of rainfall this year has taken a heavier toll on the lake, as earlier this month some of its monitoring stations recorded water levels very close to their historic lows, according to Tan.
In addition, 29 dams built on the upper reaches of the Yangtze, with a total storage capacity of 53 billion cubic meters, also contributed to the early arrival of Poyang's dry season, said Wang Hao, an expert with the China Institute of Water Resources and Hydropower Research.
CRIES FOR WATER
Statistics from the provincial flood control and drought relief headquarters showed more than a million people living around Poyang have been suffering drinking water shortages since late October. Some counties have had to suspend industrial water use to ensure supplies to residents.
Yu Xiaoqiu, general manager of a water works facility in Duchang County, has acutely felt the growing hardship of supplying water to the county's more than 130,000 residents.
"We have had to set up extra equipment to pump water from the lake in the dry season in recent years. That costs huge human and financial resources," Yu said, adding that this year they used seven water pumps, compared to the four or five used several years ago.
Before the pumps began operating on Oct. 25, tap water had been cut off for nearly all the county's residents living above the third floor, according to Yu.
The prolonged dry season has also endangered the livelihoods of local fishermen, as September and October used to be the natural "golden period" for fishing.
They expected their income this year to plummet by 80 percent compared with several years ago, and some have made a career switch.
"In the good old days, I could easily get a harvest worth more than 4,000 yuan (656 U.S. dollars) a day in early November. But today, no more than 1,000 yuan," said Xiong Qin, a 45-year-old fisherwoman in Yugan County.
Humans are not the only victims. Lingering low water levels have killed a growing number of bottom-dwelling lake creatures, meaning less food for the lake's hundreds of thousands of migratory birds, said Dai Nianhua, head of the Poyang Lake Research Center of Jiangxi Provincial Academy of Sciences.
While the local government has taken contingency measures to ensure water supplies for residents and irrigation, experts suggested a package of measures be adopted to tackle the lake's water crisis.
Wang Hao, who is also an academician of the Chinese Academy of Engineering, proposed establishing a system to manage water discharge and dam storage upstream on the Yangtze and of dams built on the five rivers flowing into Poyang.
"If all the dams were to store water simultaneously, the Yangtze would dry up, and if they discharge water at the same time, there would be a flood peak. Therefore we must decide the order," said Wang, adding that he is carrying out related research.
Xu Xinfa, deputy director of the Jiangxi Provincial Hydraulic Research Institute, suggested upgrading existing irrigation facilities and pump stations, whose outdated designs cannot handle low water levels.
In fact, the provincial government of Jiangxi has been lobbying hard for a water project planned at the mouth of Poyang.
However, their idea to build sluice gates to help the lake store water during its dry season has aroused concerns that it may have a negative impact on the lake's ecology and affect water supply to areas downstream on the Yangtze during dry weather.
Despite opposition, the project passed the technical review of the Ministry of Water Resources this summer and is awaiting approval from the ministries of agriculture, forestry and environmental protection.