Poyang Lake

Poyang Lake is China’s biggest freshwater lake. It sits in Jiangxi Province, within Jiujiang Prefecture, and is supplied by the Gan, Xin, and Xiu Rivers. The lake drains north into the Yangtze River via a single channel. Its surface area shifts wildly between wet and dry seasons, but over the past few years the overall size has been shrinking. In an average year, the lake covers about 3,500 square kilometers. In early 2012, a combination of drought, sand mining, and water held back by the Three Gorges Dam reduced it to roughly 200 square kilometers. The lake supports half a million migrating birds and is a popular spot for birdwatchers. Each winter, as many as 90 percent of the critically endangered Siberian crane population gathers there.

Historically, Poyang Lake was called Pengli Lake, though the two are not identical. Before the Han dynasty, the Yangtze ran farther north, through what is now Longgan Lake, and Pengli Marsh was simply the lower part of the Gan River. The area that became Poyang Lake was then a plain along the Gan. Around AD 400, the Yangtze shifted to a more southerly course again, causing the Gan to back up and form the lake. It was named after Poyang County, which it flooded along with Haihun County, forcing residents to move to Wucheng Township in present-day Yongxiu County. That relocation made Wucheng one of Jiangxi’s great ancient towns, and it gave rise to the saying, “Drowning Haihun County gives rise to Wucheng Township.” The name Poyang itself comes from the earlier Qin-dynasty Po County, which was named for the Chu-state city of Poyi. The lake reached its largest size during the Tang dynasty, covering about 6,000 square kilometers.

A fishing ban has been in place since 2002, and in January 2020 China imposed a ten-year fishing moratorium on 332 sites along the Yangtze, including Poyang Lake, to protect marine life. In 2007, concerns emerged that the finless porpoise—locally called the jiangzhu, or “river pig”—which lives in the lake and also in Dongting Lake, might go extinct like the baiji, the Yangtze river dolphin. Calls for action followed. Around 1,400 porpoises remain, with 700 to 900 in the Yangtze and about 500 in Poyang and Dongting Lakes. The 2007 population was less than half of what it was in 1997, and the number is dropping by 7.3 percent each year. Sand dredging has become a key part of the local economy in the area bordering the lake, but high-density dredging projects are a major cause of wildlife deaths. Dredging makes the water muddier, reducing the porpoises’ visibility, so they must rely on their sonar to find food and avoid obstacles. Large ships enter and leave the lake at a rate of two per minute, and this heavy traffic makes it hard for the porpoises to hear their prey and to swim freely across the lake. The planned Poyang Lake Dam is expected to cause further harm to the remaining porpoises.

The Three Gorges Dam, upstream on the Yangtze, causes Poyang Lake to shrink and dry up seasonally. In 2012, the lake nearly dried out completely; only 200 square kilometers were underwater in October, compared to the normal full area of 3,500 square kilometers. Besides the dam, which must store water for winter use, a drought was also blamed. The Jiangxi local government has proposed building the Poyang Lake Dam—a sluice wall across the lake’s connection to the Yangtze—to keep water levels stable. An environmental impact assessment is still pending. Scientists and groups like the World Wide Fund for Nature have criticized the plan, arguing that artificially controlling water levels would hurt wildlife diversity.

In 2019, Conservation International China started work in the Poyang Lake basin using the Freshwater Health Index to identify problems and set priorities for protecting wetland ecosystems and using resources sustainably.

In 1363, the Battle of Lake Poyang took place there, often called the largest naval battle in history.