黄河中下游大型水库对下游河道的减淤作用

本文采用泥沙数学模型分别对小浪底水库单独运用以及小浪底与古贤水库联合运用的20个可能运行方案条件下,黄河下游河道的冲淤过程和发展趋势进行了计算研究。结果表明,在黄河上修建大型水利枢纽工程对减轻黄河下游河道淤积,遏制河床抬升具有明显作用。结合三门峡水库运用以来的实测资料,分析了大型水利枢纽工程运用与下游河道演变的内在规律,建立了小浪底水库出库水沙与下游河道泥沙冲淤的量化关系,给出了维持下游河道冲淤平衡的临界条件,为通过大型水利枢纽工程运用来减轻黄河下游河道泥沙淤积提供科学依据。

Effect of large-scale reservoirs on sedimentation reduction in Lower Yellow River

The mathematical model for calculating sediment transport is applied to analyze the silting processes and developing tendencies in Lower Yellow River under the conditions of only Xiaolangdi Project is put into operation or it is operated combining with the Guxian Project. More than twenty operation schemes are calculated. The observation data of the Sanmenxia Project are used to further analyze the relationship between the project's operation modes and fluvial processes of downstream river section. On this basis, the quantitative relationship between water-sediment discharged from the Xiaolangdi Project and variation of sedimentation in the Lower Yellow River is established. The critical concentration of sediment released from Xiaolangdi Resevoir for main taining the equilibrium between erosion and silting is deduced. It is concluded that the large-scale projects are effective in reducing the silting in downstream river and the equilibrium between silting and erosion can be achieved if the sedimentation concentration in flow discharged from reservoir is 21kg/m3.