长江沙量变化和减沙途径探讨

Variation of Sediment Transportation in the Yangtze River and the Way for its Reduction

本文主要探讨长江上游输沙量、含沙量变化和减沙途径。在上游生态环境破坏程度日益加剧的情况下 ,1 95 0～ 1 985年长江输沙量、含沙量约每 1 2年以 4%的速率缓慢增长 ,1 992～1 997年大量减少。追根溯源系水库淤积的减沙作用。若无水库淤积拦沙 ,长江上游输沙量、含沙量年增长率将约达 1 % ,是相当可观的。根据水库拦沙效益 ,提出长江上游修建溪洛渡、亭子口、瀑布沟、构皮滩和白鹤滩等 5座大型水电站 ,与三峡枢纽共同进行水库泥沙联合调度 ,可使宜昌河段含沙量减少 1 / 2的年限延长达 1 5 0～ 2 0 0年 ;同时开展水土保持 ,可改变三峡下游河床冲刷后再淤积的不利局面。治水必治沙 ,通过“蓄水减沙 ,借水攻沙”的工程措施 ,和坚持不懈的水土保持 ,“标本兼治”,可使长江输沙量、含沙量长期减少 1 / 2 ,恢复到唐宋时代水平。

The variation of the sediment transportation and concentration in the upper reaches of the Yangtze River is described, and the way for reducing sediment transportation is discussed. With the co environment deterioration,the sediment transportation and concentration are increased by 4% every 12 years from 1950 to 1985. The remarkable decrease of the sediment transportation and concentration between 1992 and 1997 is due to the reservoir deposition, otherwise, it would have been increased annualy by 1%. If Xiluodu, Tingzikou, Pubugou, Goupitan & Baihetan reservoirs with the major purpose of electricity generation are built and co operated with the Three Gorges Project, the sediment transportation and concentration of the Yichang section of the Yangtze River will be half of nowadays and will last for 150～200 years. With water and soil conservation, the re deposition of the lower reaches downstream from the Three Gorges Project will be avoided. With all these ways, the sediment transportation and concentration of the Yangtze River will be half of nowadays for a long time and close to the situation of the Tang and Song dynasty.