中文摘要：

全面分析了小浪底水库蓄水拦沙期2000～2006年库区及下游河道泥沙冲淤调整；在分析泥沙输移规律的基础上量化了连续冲刷状态下河道输沙能力变化与累计冲刷量间的关系，揭示了冲刷条件下河道输沙能力降低是因为床沙有效交换层内小于0．05mm的细沙及中沙补给不足造成的；结合三门峡水库拦沙期的观测资料，对比研究了异重流洪水期间小浪底水库的排沙效果及其下游河道对高含沙异重流水沙过程的响应，指出了小浪底水库对洪水具有较大的“拦粗排细”潜力，且高含沙异重流洪水不会造成河道严重淤积。因此，在洪水调度中，要充分利用水库塑造异重流洪水，多排少拦，以达到下游河道长期减淤的目的。

英文摘要：

Based on the observed data in years from 2000 to 2006, the erosion and deposition in Xiaolangdi Reservoir area and the Lower Yellow River have been analyzed. Under persistent scouring state, the relationship between sediment carrying capacity and accumulative erosion has been quantified according to sediment transport law. It is pointed that the reason of the decrease of sediment transport capacity is the inadequate supplement of fine and medium sized sediment （less than 0.05mm） within effective bed exchange layers. With reference to the observed data during the period of Sanmenxia Reservoir impoundment, the sediment discharging effect through density current floods of Xiaolangdi Reservoir and the response of the Lower Yellow River have been compared and, studied. Xiaolangdi Reservoir provids a great potential for detaining coarse and releasing fine sediment. It is found that hyper-concentrated density current floods would not result in severe deposition in the Lower Yellow River. Therefore, it is possible to fully use the natural or artificial density currents to discharge more sediment and realize the sedimentation reduction Of the Lower Yellow River for a long time.