长江上游梯级水库群拦沙效果分析

中文摘要: 水库发挥重要的拦沙作用，改变水库下游的水沙条件。自2003年三峡工程投入运行后，长江上游水利水电工程建设进入高峰期，未来将建成超大规模的水库群，其拦沙作用将急剧改变三峡工程入库泥沙条件。为此，本文对长江上游水库群（含已建、在建、拟建水库）的拦沙效果进行综合分析，预测了三峡入库泥沙量。水库群涉及的水库共计66座（1995年以前建成的水库不计），计算采用基于Brune拦沙率的分组方法，采用1991-2000实测水沙序列的均值作为输入。结果表明，在2015-2050期间，水库群拦沙作用突出，三峡入库沙量降至每年约6000万吨，仅为1991-2005年均值的15%左右。
Abstract:Reservoirs play a pivotal role in trapping sediments and reducing sediment load into the downstream reach. The construction of reservoirs in the upper Yangtze River had reached its peak since 2003 when the Three Gorges Reservoir was putted into operation. This could greatly change the sediment condition of the Three Gorges Reservoir. To study this effect, this study presented the impact of 66 reservoirs (in operation, under construction, or being planned) in the upper Yangtze River on sediment trapping, based on which sediment load into the Three Gorges Reservoir was predicted. The analysis used the measured 1991-2000 hydrologic series as input, and the calculation of trap efficiency was based on the method proposed by Brune. The results indicate that, due to sediment trapping by the reservoirs, sediment load into the Three Gorges Reservoir drastically reduces to 60 million tons per year, accounting for only 15% of the average yearly sediment load during 1991-2005.