黄河下游防洪减淤对洪水水沙搭配的要求

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，分析了下游河道淤积严重的水沙搭配情况；利用1960～1999年422场洪水资料建立了黄河下游4个河段洪水排沙比综合水沙与边界系数的关系，该系数包括流量、含沙量、洪峰流量变幅、洪水沿程衰减系数、洪水历时、早滩流量、前期累积淤特别是等因素；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之间的关系；被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。

CRITICAL BETWEEN SCOUR AND SILTATION FOR FLOOD SEASONS IN THE LOWER YELLOW RIVER

The channel bed of the lower Yellow River changes tremendously during flood seasons because of great sediment. Critical conditions between scour and siltation are distinct in different river reaches. The paper summarized previous researches on the critical conditions for the lower Yellow River, analyzed statistically the hydrological data of 422 floods from 1960 to 1999 and set up critical equations for the 4 river reaches. The critical relations between flow discharges and sediment concentration for the 4 river reaches are shown as Fig.4, which indicates that the river channel would be scoured when flow is relatively clear, and 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.