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.