Regulation of the Main River Channel to the Sediment Discharge of the Yangtze Basin
长江干流河道对流域输沙的调节作用

Based on the data from the Yangtze Water Resource Committee and the estimation of the sediment supply from the ungauged area in the Yangtze Water basin, this paper established a sediment budget of the Yangtze River and studied the responses of the main river channel to the water and sediment supply in the Yangtze basin and the effects on the sediment supply to the sea. The results show that the average accretion velocity of river channel in the Pingshan-Datong section is 88.58×106 t/a, which is 14% and 21% of the total sediment supply from the basin and sediment discharge at Datong station respectively; sediment discharge at Datong station decreases by 17.5% because of the deposition in the main river channel, which is moderate in the upper reach and serious in the middle reach; slight erosion occurs in the Hankou-Datong section. Generally, the erosion/accretion amount has significant relationship with the total sediment supply from the basin but responses of each section of the river channel are quite different. Neither the water nor the sediment discharge has significant relationship with the erosion/accretion amount at the upper reach. The erosion/accretion amount has significant relationship with the total sediment supply in the Yichang-Hankou section and with water discharge at Datong in the Hankou-Datong section. The impoundment of the Three Gorges Dam (TGD) has effectively changed the erosion/accretion pattern of the main channel of the Yangtze.