中文摘要：

利用长江干流和主要支流上测站1956～2004年的输沙量资料,对干流未测区域的来沙进行了估计.根据泥沙平衡（Sediment budget）概念,对长江干流河道的冲淤对来水来沙的响应以及对入海泥沙的影响进行研究发现,长江干流屏山至大通河道平均淤积速率为88.58×10^6 t/a,河道淤积占总的来沙量及大通站输沙量比例分别为14%与21%.由于河道淤积,大通站输沙量减少了17.5%.总体来说上游淤积较轻,宜昌至汉口区间淤积严重,汉口至大通区间为微冲.长江于流的河道冲淤与流域总的来沙具有显著的相关关系,但各段河道的冲淤对流域来沙的响应各不一样.上游的冲淤与流域的径流量和来沙量均没有很好的相关性,宜昌-汉口段河道冲淤的变化与宜昌站的来沙具有显著的相关性：影响汉口-大通间河道的冲淤变化的主要因素是流域的来水量,河道的冲淤与大通站径流量的存在显著的负相关关系.三峡水库蓄水后整个长江干流的冲淤形势发生了根本的变化.三峡水库的蓄水运用有效地减轻了洞庭湖的泥沙淤积,同时也降低了洞庭湖的对长江干流泥沙的调节作用;长江上游干流河道淤积增强,中下游河道出现冲刷,但不同的河段表现不一;中下游河道冲刷量小于预测值,三峡水库的蓄水运用直接导致了长江入海泥沙的减少.

英文摘要：

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 fiver 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 fiver channel in the Pingshan-Datong section is 88.58×10^6 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 fiver 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.