近50年来长江中游泥沙输移变化

Changes of Sediment Transport in Middle Reach of Yangtze River in Recent 50 Years

对1950年以来长江中游泥沙输移资料作了初步分析。分析结果表明:20世纪60年代下荆江裁弯后,三口(松滋口、太平口、藕池口)分流分沙减少,下荆江径流量和输沙量相应增加,洞庭湖泥沙淤积减少;80年代中期以后,长江中游干流及洞庭湖出口的年输沙量呈减少趋势,城陵矶至武汉河段河床由淤积转为趋向冲淤平衡;三峡工程初期蓄水运用后,长江中游含沙量沿程恢复距离较长,但床沙质部分恢复距离相对较短。

Field data of sediment transport in the middle reach of Yangtze River since 1950 are roughly analyzed. The analyzed results are as follows： The late 1960＇s cutoff of riverbends increased both the runoff amount and the sediment transport amount of the lower reach of Jingjiang River, while the sediment deposition decreased in the Dongting Lake area; after the mid 1980＇s, both the middle reach of Yangtze River main stem and the Dongting Lake occurred a trend of decreasing annual sediment transport as a result of decreasing sediment releasing from the upper reach of Yangtze River; and in the recent 3 years （2003 - 2006）, the Three Gorges Reservoir first impoundment additionally reduced the sediment concentration in the middle reach of Yangtze River flow with a long time, so a distance would be quite long for suspended sediment recovery, but the distance for bed-material load of suspended sediment recovery would be quite short.