Dongting Lake (洞庭湖) is a large, shallow lake in northeastern Hunan, a flood basin of the Yangtze into which four great rivers — the Xiang, Zi, Yuan and Li — empty. Its size is seasonal: normally about 2,820 square kilometres, in the July-to-September flood months it can grow to 20,000 as Yangtze water and sediment pour in, and its level swings by nearly thirteen metres a year. Once China's largest freshwater lake and praised as eight hundred li of Dongting, it is now second to Poyang Lake after centuries of reclamation. By tradition dragon boat racing began on its eastern shore in the search for Qu Yuan's body; the lake is a Ramsar wetland, a wintering ground for more than 130 bird species, and home to the endangered Yangtze finless porpoise.
Dongting Lake is a Yangtze flood basin that four Hunan rivers fill with water and silt, and its shoreline has been moving for centuries. These sections follow the rivers, the drowned and reclaimed land, and the dikes and reserves that manage the lake today.