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为系统揭示长江中游近期枯水情势及其对三峡水库蓄水的直接和间接响应,本文以冲刷剧烈、枯水位降幅最大的上荆江为例,通过统计其不同形式枯水位的变化特征,建立了水位下降与河床冲刷、水库不同运行方式的相关关系。结果表明,沙市站同流量枯水位几乎与枯水河槽河床平均高程等幅下降,枝城站枯水位下降幅度较小与本底河床形态、河床粗化及航道整治工程有关。上荆江汛前枯水位降幅、最低水位及极枯水位历时等枯水情势会受到三峡水库补水调度的影响,这种补水效应沿程递减,至沙市站补水调度仍然无法抵消河床下切对枯水位造成的影响。
In order to systematically reveal the recent dry conditions in the middle reaches of the Yangtze River and its direct and indirect response to the impoundment of the Three Gorges Reservoir, this paper takes Shangjing River, where the erosion is drastic and the water level declines the most, as an example. By analyzing the variation characteristics of its dry form, Decreasing water level correlates with riverbed erosion and different reservoir operation modes. The results show that the dry flowrate of Shashi Station is almost the same as that of the dry river bed, and the decrease of the dry water level of Zhicheng station is less related to the background riverbed morphology, riverbed coarsening and waterway regulation. On the Jingjiang flood declines before the flood, the lowest water level and extremely dry water level and other dry water situation will be affected by the Three Gorges reservoir replenishment schedule, this replenishment effect decreases along the way to Shashi Station replenishment schedule still can not offset the riverbed undercutting caused by low water level Impact.