黄河下游河道洪水冲淤与水沙搭配关系

本文总结了以往对黄河下游河道冲淤临界条件的研究情况；利用1960～1999年422场洪水资料分析了影响洪水冲淤的各种水沙因素，建立了黄河下游4个河段洪水排沙比与综合水沙系数的关系，该水沙系数包括流量、含沙量、洪峰流量变幅、洪水沿程衰减系数、洪水历时等5个因素；利用4个河段的冲淤临界条件勾画出了4个河段洪水冲淤调整与来水来沙搭配(或组合)之间的关系；该关系可为小浪底水库调度决策以及黄河下游治理提供参考。

Relation between scour/siltation and flow/sediment combination for floods in the lower Yellow River

The channel bed of the lower Yellow River changes tremendously during flood seasons because of great sediment.Flow and sediment conditions for scour and siltation are distinct in different river reaches.The previous researches on the relation between channel formation and flow/sediment conditions are summarized for the lower Yellow River,the hydrological data of 422 floods from 1960 to 1999 are statistically analyzed and the sediment transport equations are set up for the 4 river reaches.Then the critical conditions between scour and siltation for the 4 river reaches are derived as a function of flow discharge and sediment concentration as shown in Fig.5,which indicates that the river channel would be scoured when flow is relatively clear,and would be filled when flow is relatively muddy.These relations may be used in the regulation of Xiaolangdi reservoir in order to mitigate sedimentation for the lower Yellow River.