渭河下游河道泥沙分布特性研究

Study on Characteristics of Sediment Distribution of the Lower Channel of Weihe River

根据渭河下游河道大断面淤积物资料,研究了滩槽床沙粒度特征在时间、空间上的分布特点,认为:渭河下游淤积物组成受来水来沙条件、三门峡水库运用方式和支流入汇等多方面因素影响;主槽物质沿程细化趋势明显;三门峡水库运用初期,渭河下游河道受水库淤积影响最为明显,渭淤21以下的水下粒径组成明显细化;1986年以后渭河上游不利的来水来沙造成下游河道严重萎缩,渭淤26以下的主槽粒径大幅度细化;河漫滩的泥沙级配同样具有沿程细化的特点,但细化幅度明显小于主槽物质的变化,而且年代变化不大。

The paper studies the temporal and spatial distribution characteristics of grain size of bed material of floodplained trough based on the data of deposit of channel cross-section of the lower Weihe River,deems that the deposit composition of the lower Weihe River is affected by multi factors of incoming water and sediment condition,the operational mode of Sanmenxia Reservoir and inflow and confluence of tributaries;the composition of grain size downstream Weiyu CS-21 is obviously getting finer;the lower channel is seriously wilted caused by unfavorable incoming water and sediment from the upper river since 1986 causing fine grain size of the main channel in the downstream of Weiyu CS-26 in a large scale and;the sediment gradation of alluvial plain also has the characteristic of getting finer along the river,while the degree is obviously smaller than the variation of main channel and the years variation is small.