黄河下游造床流量的变化及其对河槽的影响

本文通过计算黄河下游的第一造床流量和第二造床流量，分析了黄河下游河槽的萎缩过程。第一造床流量与年水沙量的关系分析表明，黄河下游的深槽平浅滩流量700～1000m3/s是相对稳定的，恒定流的平衡输沙能力约为18～21kg/m3。通过小浪底水库拦粗排细年平均拦沙约3亿t，并在汛期强化调水调沙运用，基本可以控制黄河下游河槽的淤积萎缩。第二造床流量和平滩流量的关系分析表明黄河下游恢复和维持平滩流量约4000m3/s的中水河槽是比较合理的。根据小浪底水库调水调沙运用状况，提出了恢复和维持黄河下游稳定中水河槽的措施，并探讨了强化小浪底水库调水调沙运用的方案。

Variation of dominant discharge in Lower Yellow River and its influence on river channel

The first dominant discharge and second dominant discharge of the Lower Yellow River are calculated to analyze the processes of channel shrinkage. The relationship between the first dominant discharge and annual quantity of water and sediment indicates that the deep main channel with shallow bankfull discharge of 700 - 1 000m^3/s is relatively steady, and the channel shrinkage due to silting is controllable by means of reasonable operation of the Xiaolangdi Reservoir, by which about three hundred million tons of coarse sediment is detained annually only fine sediment is released, resulted in strengthening of the regulation of flow and sediment. The relationship between the second dominant discharge and bankfull discharge indicates that it is reasonable to resume and keep the middle flood channel with bankfull discharge about 4 000m^3/s. Integrating with the practice on flow and sediment regulation in field the measure to resume and keep the river channel to fit the middle flood is suggested and the suggestion for strengthening the regulation scheme of the Xiaolangdi reservoir is proposed.