长江中游坡陡流急河段枯水位变化及其影响研究

    Study on variation and impact of low water levels in steep riverbed and rapid flowing sections of middle reaches of Changjiang River

    • 摘要: 枝城—大埠街河段为长江中游典型的“坡陡流急”河段,受清水下泄影响,该河段枯水位沿程持续下降,严重影响船舶通航。基于实测资料分析了枝城—大埠街河段历史水沙过程和枯水位变化特征,并结合二维水流数值模拟方法,预测了下游不同水位降幅对上游的溯源传递影响范围及其对通航条件的影响。结果表明:①三峡水库蓄水以来,输沙量大幅度减少,研究河段的枯水位下降幅度表现出“中间小,两端大”的特点,河段内“坡陡流急”的现象也随之恶化。②预测大埠街枯水位下降导致的溯源传递主要影响范围为昌门溪以下河段,其中枝江—江口河段的流速和水深受下游水位影响最大。③芦家河水道、枝江水道、江口水道200 m局部比降将达到1.2‰,0.9‰,0.5‰以上,部分浅段的通航水深难以满足通航要求,且存在多处小于3.50 m通航水深的浅段,将严重影响船舶通航。研究成果可为长江中下游河段船舶通航及航道规划提供参考。

       

      Abstract: Zhicheng—Dabujie section is a typical steep riverbed and rapid flowing section in the middle reaches of the Changjiang River.Affected by the discharge of clear water, the water level during dry seasons in this section has been continuously declining along the course, severely impacting navigation.Based on measured data, the historical hydrological and sedimentary processes and the characteristics of water level changes during dry seasons in the Zhicheng—Dabujie section were analyzed.Combining with a two-dimensional hydrodynamic numerical simulation method, we predicted the upstream influence range due to the different downstream water level drops and their impact on navigation conditions.The results indicate that: ① Since the impoundment of the Three Gorges Reservoir, the sediment transport have significantly decreased.The water level decline during dry seasons in the study section exhibits a pattern of low in the middle reach and high at both ends, and the steep riverbed and rapid flowing phenomenon in the section has worsened.② The retrogressive influence caused by the water level decline during dry seasons at Dabujie mainly affects the section below Changmenxi, with the Zhijiang—Jiangkou section being most significantly influenced in terms of flow velocity and water depth.③ The local gradients of the 200-m sections in the Lujia River channel, Zhijiang channel, and Jiangkou channel will reach above 1.2‰, 0.9‰, and 0.5‰, respectively.The navigable water depth in some shallow sections will fail to meet navigation requirements, moreover, there are several sections with navigable water depths less than 3.50 m, which will severely impact navigation.The research findings can provide references for navigation and channel planning in the middle and lower reaches of the Changjiang River.

       

    /

    返回文章
    返回