2.1 Study area
Study area in the Poyang Lake basin, which belongs to the south bank of
the middle Yangtze proper and connects with the Yangtze River, with
latitude 28°22 ’– 29°45’ north and longitude 115°47 ’– 116°45’
East. The basin covers an area of 162225km2. The
Poyang lake basin has five streamflows, including the Ganjiang, Fuhe,
Xinjiang, Raohe, and Xiushui. Those ‘five rivers’ runoff flow into
Poyang Lake and retarded. After inflow storage, the lake water flows
into the Yangtze River through the estuary of the lake. Meanwhile,
because of the connection with the Yangtze River, the Yangtze River
runoff also will flow into the lake through the lake estuary (Shankman,
Keim, and Song 2006).
Poyang Lake basin belongs to the subtropical monsoon climate, with
intense solar radiation. Due to the apparent difference in precipitation
in the basin, the seasonal variation of runoff into the lake of the
”Five Rivers” is very significant; from April to September, the runoff
into the lake accounts for 75% of the whole year. Therefore, the flood
season in Poyang Lake is from June to September yearly, and the dry
season is from November to February the following year. In winter, the
area of the lake shrink, and the lake bed is bare(X. Li and Zhang 2015).