长江黄陵庙至南津关河段河势分析

River channel process of Huanglingmiao-Nanjinguan river reach

随着通航、调度及生态方面需求的提高,对葛洲坝和三峡大坝两坝间河段进行新一轮治理已迫在眉睫。根据葛洲坝工程运行以来的实测资料,对该河段30余年来的河势变化进行了分析。分析表明:葛洲坝工程运行后至1983年,两坝间河段明显淤积,其后至1998年,淤积进程趋缓;1998年以后有一定的冲刷,尤其在2003年三峡工程运行以来,两坝间河段处于累积性的冲刷状态,冲刷部位主要以深槽为主,冲刷深度较大的河段主要发生在乐天溪深槽段和南津关深槽段,河段中部较为稳定;2008年后,冲刷幅度变小,个别年份甚至有回淤。30年来,河段先淤后冲,渐趋平衡,河势较为稳定;三峡工程运行后,两坝间冲淤与三峡工程下泄沙量关系并不明显,而受汛期来水影响较大,考虑到三峡水库仍将持续进行试验性蓄水,逐渐进入正常运行期,其中小洪水调度及汛期滞洪作用都将增强,洪水流量过程的调平在所难免,因此两坝间冲刷将不易发生,小幅淤积极为可能,总的河势及深槽大小、位置将相对稳定。

With the new demands of the 12th Five-Year Plan, in terms of navigation, reservoir operation and ecology, new river regulation works for the reach from the Three Gorges dam to the Gezhouba dam are required. So it is very important to recognize the evolution of the river in the recent years. Based on the measured data since the Gezhouba dam was operated, the river channel process between two dams in recent more than 30 years is analyzed. From 1979 to 1983, the river reach silted obviously; from 1983 to 1998, the siltation process slowed down considerably. After 1998, erosion of bed was beginning, in particular, since the operation of the Three Gorges dam in 2003. The deep channel was eroded remarkably in the cross section, along the longitudinal direction, Letianxi and Nanjinguan river reach were eroded mostly, and the middle reach was in a stable condition. Since 2008, the erosion of bed has become slow. In the past 30 years, the river bed was scoured after deposition and became balanced gradually, and the river regime was stable. After the operation of the Three Gorges dam, there was no clear relationship between the reach channel process and sediment condition, but it was influenced distinctly by the flood. The Three Gorges reservoir will continue to test operation, and will gradually enter the normal operation period, the river reach between the two dams will be not easily deposited, slight siltation will be extremely possible, and the river regime and the most part of the channel will be relatively stable.