Study On Annual Runoff And Annual Sediment Discharge In The Main Stream Of Xijiang River

The Xijiang River Basin accounts for 77% of the Pearl River Basin area,and is the main river system of the Pearl River.In recent years,many scholars have studied the changes of water and sediment in the Xijiang River Basin,but all of them were in the conventional method to analyze only the hydrological data of the single main stream hydrologic station and the short-range main stream and branch hydrologic station,which could not fully reflect the evolution law of the water and sediment in the Xijiang River Basin.Paper is based on the runoff and sediment data of the Qianjiang hydrological station of the Red River in the Xijiang River Basin,the Da Huangjiang estuary hydrological station of Xun River,the Wuzhou hydrological station and the Gaoyao Hydrological Station of the Xijiang River from 1957 to 2016.Using the Mann-Kendall trend test method,5 year sliding test method and cumulative anomaly method,the simulated annealing algorithm is also used for the first time to analyze the variation of annual runoff and annual sediment transport in the West River Basin.The results show that:(1)The runoff and sediment discharge of the Qianjiang hydrological station was fluctuated,but the overall trend showed a significant downward trend.There is no significant change trend of annual runoff in Da Huangjiang estuary hydrological statio,Wuzhou hydrological station and Gaoyao hydrologic station,but they all show an upward trend.On the other hand,Da Huangjiang estuary hydrological station,Wuzhou hydrological station and Gaoyao Hydrological Station annual sediment transport trend was decreased significantly.(2)There is no jump point in annual runoff of the Dahuangjiang hydrological station,the Wuzhou hydrological station and the Gaoyao Hydrological Station except for the Qianjiang hydrological station.The Qianjiang hydrological station occurred abrupt in 2002.(3)The annual sediment transport of the Qianjiang hydrological station,the Dahuangjiang estuary hydrological station,the Wuzhou hydrological station and the Gaoyao Hydrological Station have significant abrupt mutation points.The significant mutation time was in 1991,1997,1994 and 1999,and the main cause of the mutation was the action of human activity.(4)The annual runoff and annual sediment discharge of the Qianjiang hydrological station,the Dahuangjiangkou hydrologic station,the Wuzhou hydrological station and the Gaoyao Hydrological Station were calculated by weighting.The annual runoff and annual sediment discharge of the Xijiang hydrological station can be obtained,which can represent the water and sediment of the main stream of the Xijiang River basin in the study area.(5)The fitting rate of sediment discharge in the Xijiang River Basin is the highest.The correlation coefficient R is 0.87321.(6)The trend of annual runoff variation in the main stream of the Xijiang River Basin is slightly fluctuating,and the annual variation of the runoff is small,but the annual sediment transport has a downward trend in general,and its catastrophe point is in 1990.(7)There is a correlation between annual runoff and annual sediment discharge in the main stream of Xijiang River.Human activity is the main factor to reduce sediment discharge in Xijiang station.