长江泥沙输移及三峡工程泥沙问题

Sediment Transport in Yangtze River & Sediment Issues in TGP

长江泥沙主要来自上游金沙江和嘉陵江，来沙、来水分别占宜昌站的70％和49％。地表侵蚀以水力侵蚀和重力侵蚀为主，但输沙量远小于侵蚀量。水土保持和兴建中小型水库的拦沙作用明显减少了进入河道的泥沙，与人类活动加剧水土流失所带来的负效应部分相互抵消。经综合对比分析，从宏观上看，宜昌站输沙量多年平均值相对稳定。三峡水库为河道型水库，长600km，水库来水量大，含沙量较小。水库采同“蓄清排浑”的调度运行方式可做到长期保留大部分有效库容。

The sediment in the Yangtze river mainly come from the Jingsha river and the Jialing river, accounting for 70% of the total at the Yichang station. The hydraulic and gravity erosion are prevailing in surface water erosion, but the sediment transport is much less than the erosion. Soil conservation programs and construction of medium and small -sized reservoirs significantly have reduced the sediment entering the river. The Three Gorges Project has a rivertype reservoir, with a length of 6OO km, a larger inflow and less sediment content, and can maintain the most of the effective storage capacity for a long term by an operation mode of ' Impounding clean water and discharging mud flow