黄河下游河道排沙比、淤积率与输沙特性研究

Study on Sediment Delivery Ratio,Rate of Silting and Characteristic of Sediment Transport of the Lower Yellow River Channel

以小浪底水库拦沙后期运用为前提条件,根据黄河下游历次洪水的场次水沙资料,提出了下游河段全段及分段的排沙比关系式,分析表明黄河下游上段河道冲淤幅度较下段大,所以河床演变迅速且不稳定;下段河道断面窄深,经上段对水沙调节后,下段冲淤幅度小,河床平稳,但是输沙入海的瓶颈河段。水库调节对下游的减淤效果不大,相反会使入海沙量减少,水库淤积加快及输沙用水增加,水库如何适度拦沙是需要进一步研究的问题。

The paper puts forward the relational expression of sediment delivery ratio of the whole section and section by section of the lower reaches based on silt-discharge data of each flood occurred in the lower Yellow River and on the operational conditions of late period of debris retaining of the Xiaolangdi Reservoir.The outcomes show that the range of channel scour and fill of the upper section is greater than that of the lower section,therefore,the evolution of river bed of the lower Yellow River is fast and unstable;the cross section of the lower section where is bottle-neck section for transporting sediment into the sea,is narrow and deep,the range of scour and fill of the lower section is small and river bed stable after regulating discharge regime at the upper section.The effect of reservoir regulation to the sediment reduction of the lower channel is small.On the contrary,it reduces the amount of sediment flowing into the sea,speeding up the sedimentation in the reservoir and increasing the water consumption for sediment transport.How to properly control sediment by the reservoir is an issue and needs further study.