Water and Sediment Exchange between the Yangtze River and the Poyang Lake, the Largest Freshwater Lake in China

In view of the complicated water and sediment exchange between Poyang lake and external Yangtze River, a 2-D unsteady numerical model with water current and sediment coupled was established. The hydrological condition in the common-water year (2010) was used for a yearly numerical simulation to investigate the water and sediment exchange mechanisms. The results showed that: The annual water volume flowing to the Yangtze River from Poyang Lake was about 2.17×1011 m3. Due to the periodical jacking influence of the external water level, about 1.06×1010 m3 water quantity flowed back into the Lake from the Yangtze River. The water exchange between Poyang Lake and the Yangtze River varied evidently with seasons, which was mainly concentrated in March and September. The annual sediment exported from Poyang Lake to the Yangtze River was about 1.53×107 t ,and the amount of sediment flowing back to the lake was about 1.89×106 t.