三峡-葛洲坝梯级水库不同蓄水阶段对其下游泥沙特性的影响分析

为了分析三峡-葛洲坝梯级水库对长江泥沙特性的影响,选取位于三峡-葛洲坝梯级水库上游和下游的寸滩和宜昌水文站为研究站点,以葛洲坝及三峡水库建设和运行的不同阶段划分研究时段,利用寸滩、宜昌1954—2012年的长系列日流量和日含沙量资料,从年、月、日3个时间尺度定量分析三峡-葛洲坝梯级水库上游对下游泥沙特性的影响。结果表明:三峡-葛洲坝梯级水库对其下游年、月、日尺度的泥沙特性影响随水库库容、运行阶段的变化而变化;库容越大,蓄水位越高,影响越显著。研究成果旨在为分析评价大坝的运行对长江生态系统健康与稳定性的影响提供参考。

Analysis of impacts of different impound phases of Three Gorges-Gezhouba cascade reservoirs on sediment regime in downstream

To analyze the impacts of Three Gorges-gezhouba cascade reservoirs on the sediment regime in the Yangtze River downstream, two hydrological stations Cuntan and Yichang which were respectively located in the upstream and downstream of Three Gorges-gezhouba cascade reservoirs were selected as study sites. The whole study period was divided into several sub-periods according to the different phases of construction and operation of Gezhouba and Three Gorges Reservoirs. On the basis of the long time series of daily water discharge and sediment concentration from Cuntan and Yichang from 1954 to 2012, the impacts of Three Gorges-gezhouba cascade reservoirs to the downstream sediment regime in annual, monthly and daily scales were investigated respectively. The results revealed: the Three Gorges-gezhouba cascade reservoirs have influences on annual, monthly and daily sediment regime, which varied according to reservoir storage capacity and operation phase. The impacts are more significant when the storage is bigger and the storage level is higher. The study is intended to provide references for the assessment of impacts of dam operation on the health and stability of the Yangtze River ecosystem.