三峡水库运用前后进出库水沙变化分析

Changes of Inflow and Outflow Runoff and Sediment of Three Gorges Reservoir Before and After the Impoundment

根据三峡水库蓄水前后实测水沙资料,对三峡水库近期进出库水沙变化进行了较为系统的分析。结果表明:上世纪90年代以来,三峡水库进出库水沙均有所减小,其中输沙量减小更为明显;蓄水运用后三峡水库汛期进出库水量、沙量占全年的比例仍分别维持在76%以上和96%以上,但从年内分配变化上看,汛期进库水、沙量占全年的比例均呈减少趋势,汛期出库水量比例呈减少趋势,出库沙量比例呈增大趋势;三峡水库蓄水运用后9-10月份进出库水沙量减小较多,而枯水期2-4月份进出库流量均呈增大趋势。

The changes of inflow and outflow runoff and sediment of the Three Gorges impoundment are systematically analyzed based on the observed data of hydrographi Reservoir before and after the c stations. The results reveal that since the 1990s, the inflow-outflow runoff and sediment have both reduced, of which the sediment discharge reduced much more remarkably than the runoff. In recent years, the inflow-outflow runoff and sediment during flood season remain above 76% and 96% of the whole year. In terms of annual distribution, the inflow runoff and sedi- ment in flood season both exhibit a tendency of decreasing; whereas the outflow runoff tends to decrease and the outflow sediment tends to increase in flood season. After the impoundment, the inflow and outflow water and sedi- ment decreased sharply in September and October, while increased in dry season from February to April.