Changes of Runoffand Sediment Discharge into Dongting Lake from the Four Rivers in Hunan Province
On the basis of hydrological data from 1951 to 2009 of four representative gauging stations （Xiang- tan, Taojiang, Taoyuan, Shimen）, the changes of runoff and sediment discharge into Dongting Lake from the Four Rivers （Xiang River, Zi River, Yuan River and Li River） in Hunan Province were investigated using Mann-Kendall trend test, moving average value and double mass analysis. The results showed that annual run- off was highest in Xiang River （657 x 108m3）, intermediate in Yuan River （640 x 108m3） and Zi River （229 x 10Sm3）, and lowest in Li River （147 ~ 108m3）. However, the changes of annual runoff of the Four Rivers were in- significant （P 〉 0.05）, with several up-down processes. Annual sediment discharge was highest in Yuan River （1 051 ~ 104t）, intermediate in Xiang River.（959~ 104t） and Li River （382~ 1040, and lowest in Zi River （199x 104 t）.The annual sediment discharge from the Four Rivers showed a significantly decreasing trend generally （P 〈 0.001）. Changes of annual runoff and annual sediment discharge were consistent in Xiang River before 1980s, in Zi River after 1960s, in Yuan River before 1980s and in Li River before 1990s. Moreover, the time of abrupt change in annual sediment discharge was different among the Four Rivers, with Xiang River in 1996, Zi River in 1973-1974, Yuan River in 1997-1998 and Li River in 1998, and the time of abrupt beyond 95% confidence interval was 1999, 1963, 1988, 2001 in Xiang River, Zi River, Yuan River and Li River, respectively. Double mass analysis between annual runoff and annual sediment discharge showed that Xiang River had one turning point in 1991, Zi River three points in 1961, 1981 and 1997, Yuan River two points in 1979 and 1997, Li River one point in 1996. Turning points of annual sediment discharge in Four Rivers were closely related to the con- struction of large-scale reservoirs. The reduction of annual runoff, increase of vegetation cover and construc- tion of medium- and large-scale reservoirs were the main reasons accounting for the great reduction of annual sediment discharges of Four Rivers after 2001.
Four Riversabrupt changehydrological processreservoir
NETL
NSTL
万方数据
维普
