Influence of Upstream Cascade Reservoir Impoundment on the Water Level in the Middle and Lower Reaches of the Yangtze River

Abstract

长江上游梯级水库运行使得长江中下游水文情势发生了变化。基于长江中下游2012年河道实测资料，构建宜昌至大通的一维水动力模型，分析了蓄水期溪洛渡、向家坝和三峡水库联合调度对中下游控制站点水位的影响。结果表明：蓄水期上游梯级水库运行一定程度上降低了下游各个站点的水位，溪洛渡、向家坝两座水库运行对长江中下游干流的水文情势影响主要集中在9月份，以宜昌站为例，两座水库运行对宜昌站9月份旬水位影响的贡献率在27.5%~88.4%，两座水库运行对干流10月份和11月份的水文情势影响较小。三峡水库运行对长江中下游干流水文情势影响主要集中在9月下旬和10月份，三峡水库对干流11月份水库影响较小。 The upstream cascade reservoirs have changed the hydrological regime in the middle and lower reaches of the Yangtze River. Based on the 2012 terrain data of the river, the one-dimensional hydro-dynamic model was used to analyze the influence of combined operations of the Xiangjiaba, Xiluodu reservoirs and the Three Gorges Reservoir (TGR) on the downstream water levels. The results show that: the water level of each station in the middle and lower reaches of the Yangtze River was dropped due to the impoundment of the upstream cascade reservoirs during the storage period. The water lev-el changed most in September and less in October and November because of impound operation of the Xiangjiaba and Xiluodu reservoirs. For example, the contribution rate of descending water level is 27.5%~88.4% due to the impounding of the two reservoirs. The water level of each station in the mid-dle and lower reaches of the Yangtze River dropped with maximum change in October and minimum change in November due to the operation of TGR.