葛洲坝-三峡水库不同蓄水阶段对中下游水沙影响

Impacts of different impoundment periods of Gezhouba and Three Gorges Reservoirs on flow and sediment load of mid-lower Yangtze River

以葛洲坝-三峡梯级水库为研究对象,根据水库的不同运行阶段划分研究时段,基于寸滩、宜昌、汉口、大通站1954~2008年的日流量和日含沙量资料,计算分析了梯级水库运行对长江中下游输沙量及水沙关系的影响。结果表明：4个水文站的年输沙量、含沙量总体呈下降趋势,梯级水库运行对中下游输沙量及水沙关系的影响与水库库容和距离水库远近有关;水库拦截造成的泥沙减少与年径流量变化无关,与径流量的季节分配变化有关,径流量季节分配的变化和梯级水库的蓄水拦沙都使大通站月输沙量的年内分配更加均匀。

We select Gezhouba and Three Gorges cascade reservoirs as the research object and divide study periods into 4 sub- periods in accordance with different operation phases of the reservoirs. Based on daily water discharge and sediment concentration data at Cuntan,Yichang,Hankou and Datong hydrological stations from 1954 to 2008,the change of sediment load and flow- sediment relationship of mid- lower Yangtze River under the operation of the cascade reservoirs is studied. The results reveal that the annual sediment load and sediment concentration at 4 hydrological stations are in a decreasing trend in general; the impact of the operation of cascade reservoirs on sediment load and flow- sediment relationship is related to the storage capacity and the distance from reservoir; the sediment decrease caused by reservoir retaining is related to seasonal distribution changes of runoff but not to the annual runoff volume variation; the annual distribution of monthly sediment load at Datong Station becomes more even due to the seasonal distribution changes of runoff volume and reservoir retaining.