黄河下游洪水期断面调整对过洪能力的影响

水位表现是水流与河床边界相互作用的客观反映。对于不同的河流二者所起的作用各不相同，一般河流，河床变形不显著，水位主要依赖于流量的大小而变化；而像黄河这样的多沙河流，周界变化迅速，尤其是洪水期，槽冲滩淤，涨冲落淤，断面调整对水位影响很大。文中从定性到定量对中低含沙量的各级洪水，主槽冲刷对过洪能力的影响进行了详细分析，成果对防洪有指导意义。

Effect of Cross Section Regulation in Flood Period on the Capacity of Conveyance Flood of the Lower Yellow River

The change of water level is the reflection of the interaction between stream flow and river boundaries. The interactions are different for different rivers. For ordinary rivers, deformations of riverbed are not intensive and changes of water level depend mainly upon changes of discharge. For rivers with sediment-laden, such as the Yellow River, changing quickly of river boundaries, channel erosion and floodplain deposition, erosion in flooding up and deposition in flooding down are the main characteristics of river variation in flood period. Cross section regulation affects the change of water level greatly. In this paper the effect of main channel erosion on the capacity of average or low sediment concentration conveyance flood are analyzed from quality to quantity in details. The research result is very significant to guide flood protection of the Lower Yellow River.