长江中游牯牛沙水道碍航原因分析

针对牯牛沙水道航道问题,根据近50年河道实测地形资料,分析了牯牛沙水道河床演变特点、碍航特性及浅区成因。结果表明:牯牛沙水道碍航主要是由于过渡段河道宽浅。虽然近年来该河段已实施的一期工程抑制了牯牛沙边滩的冲刷后退,但一期工程高程较低,未改变过渡段宽浅的河道格局,过渡段水流分散,洪枯水流路不一致,一期工程还不能完全有效导引水流冲刷过渡段浅埂,造成过渡段航槽时而出浅;且三峡工程蓄水运用后汛后退水期缩短,浅滩退水冲刷强度减弱,航道条件难以保持稳定的4.5 m水深。

Causal analysis of navigation obstacle in Guniusha waterway in the middle Yangtze River

According to Guniusha waterway problem and the topographic data of the observed over the past 50 years,this paper analyzed the Guniusha waterway evolution characteristics and the causes of navigation obstacle property and genesis of shallow region.The results show:the main obstruction of Guniusha waterway is due to its transition section wider and shallower.In recent years,the retreat of the Guniusha side foreland is confined by the first phase projects,but the framework of river reach is not changed due to the low elevation of the first phase projects.The water flow in the transition section is scattered,and the channel of flood and dry water is inconsistent,and the first phase projects are not yet fully effective in guiding water flow scoured the transition section of shallow ridge,these phenomena causes the transition section navigation channel become shallower sometimes.In addition,the descending phase of flood becomes shorter after the operation of the TGR,which weakens the erosion rate of the channel,and makes maintaining the 4.5 m waterway depth condition difficult.