长江沙市河段近期河道演变分析

沙市河段是上荆江河势较为复杂的河段之一,也是航道治理的重点河段之一。根据三峡水库蓄水以来沙市河段实测地形资料以及沙市水文站的实测水文资料,从来水来沙、深泓平面、洲滩、深槽以及横断面变化等方面系统分析了沙市河段的近期河道演变特性。结果表明:(1)三峡水库蓄水后,沙市河段整体呈现冲刷的趋势,深泓平面摆动集中在分汊段,沿程洲滩冲刷萎缩,横断面冲淤时有发生,20 m深槽冲刷发展,接近贯通。(2)受到沿程护岸工程以及洲滩守护工程等的影响,该河段总体河势基本稳定,但局部河段内仍会有所调整。(3)河段尚未达到冲淤平衡,未来一段时间内,河段仍将以冲刷为主,若无人工干预,滩槽演变趋势将延续近期的变化,由此对防洪、航运等方面带来的影响值得关注。

Analysis on recent river channel evolution in Shashi reach of Yangtze River

Shashi reach is one of the most complex reaches in the upper Jingjiang River, and one of the key river reaches need to be regulated. According to the measured topographical data of Shashi reach and hydrological data of Shashi station since the impoundment of Three Gorge reservoir, its channel evolution characteristics were analyzed from the aspects of incoming flow and sediment, thalweg variation, sandbar, deep channel and cross section. The results are as follows:① After the reservoir impoundment, Shashi reach tends to be scoured in general, the plane swinging of thalweg occurs mostly in the river branch. Sandbars in the river are scoured and shrink in size. Scouring and silting occur occasionally at cross sections. A twenty-meter deep channel is being scoured and about to be through. ② Affected by revetment project and sandbar protection project, the river regime of Shashi reach stabilized, but some reaches will still be subjected to adjustments. ③ Shashi reach has not reached a balance between scouring and deposition, and will continue being dominated by scouring in the near future; Without human interference, sandbar variations will follow a similar trend, and its impacts on flood control and navigation are worthy of attention.