三峡水库蓄水初期关洲分汊河段的冲淤调整特性分析

关洲分汊河段位于长江中游,其水流动力轴线年内随流量的变化在两汊间交替,为典型的年内交替型分汊河段。本文依据实测资料,分析了三峡工程蓄水运用初期关洲河段的冲淤调整情况,并着重对比分析了左右两汊冲淤调整进程的差异。研究发现,蓄水后关洲河段年际间有冲有淤,但以冲刷为主;冲淤主要表现为深泓下切及枯水河槽的冲淤调整;左右两汊冲刷进程不同,左汊为洪水期主汊,河床冲刷幅度较大,深泓平均高程连年递减,过水面积呈增大趋势,而右汊为枯水期主汊,其河床冲刷发展则相对缓慢,深泓高程变化较小。

Erosion and deposition of Guanzhou braided reach during initial impoundment period of Three Gorges Project

The Guanzhou reach is located in the middle Yangtze river,which is a typical alternate braided channel,for the dynamic axis of flow alternates annually.Based on the prototype observation data,this paper analyses the erosion and deposition of Guanzhou reach during the initial impoundment period of the Three Gorges Project,focusing on the comparative analysis of two branches.The analysis shows that since the commissioning of the Three Gorges Project,the Guanzhou reach has developed significantly,obviously in the left branch and the branching convergence zone.As for the scouring process,the two branches were different;the left branch,as the main channel in flood seasons,has obviously developed,getting lower and wider,while the right branch,as the main channel in dry seasons,has developed slowly.