A seasonal water system in Poyang Lake, China.
Antong Huang
2024
Poyang Lake is a throughout, seasonal lake located in Jiangxi Province, China. The hydrological conditions of Poyang Lake are driven by five major tributaries, the Gan, Fu, Xin, Rao, and Xiu Rivers, and the Yangtze River, one of the two most important rivers in China. Runoff of the Poyang Lake basin is mainly from the five major tributaries, originating from the mountains surrounding Poyang Lake and recharged by precipitation. Among them, the Gan River provides more than 40% of the water volume of Poyang Lake, accounting for the largest proportion. Most of the rivers in Jiangxi Province, including the five major tributaries, flow through Poyang Lake to the Yangtze River. Therefore, as the catchment center of its watershed, Poyang Lake controls the water balance between the watershed and the Yangtze River.
Poyang Lake is characterized by seasonal cyclic water level changes, leading to varying degrees of exposure of the lake bottom terrain and the manifestation of different water areas. In China, this seasonal variation is described as “high water is a lake, low water is a river” or “flood water is one piece, dry water is one line”. Based on these characteristics, the wet season is defined from April to October, with the water level peaking in July, while the dry season is defined from October to April, with the water level dropping to its lowest in January.
The underlying cause of this seasonal fluctuation lies in the change in precipitation and the subsequent change in runoff influenced by the monsoon in the Poyang Lake Basin. During winter, the decrease in precipitation leads to a reduction in the amount of water from the five major tributaries, with the water flowing directly into the Yangtze River through the deepest fluvial area of the lake bed. Conversely, during summer, with the precipitation increasing, the volume of water from the five tributaries rises, coupled with a larger flow in the Yangtze River. Consequently, water converges at Poyang Lake, leading to a rapid expansion of the water surface within a short period.
Circular Stories
Based on the integrated co-operation between the hydrological condition, the topography of the lake bottom, the landscape types and the time cycle of production activities, the Poyang Lake area has developed its unique annual seasonal cycle, which consists of three main landscape components (polder, sub-lake and wetland), and three sub-production-cycles (agriculture, fishery and animal husbandry). Meanwhile, harmony with the wintering behavior of migratory birds is also considered.
