黄河下游"2004·8"洪水分析

2004年8月,黄河中游地区出现强降雨过程,依据防洪方案,小浪底水库泄放了一次高含沙洪水过程。洪水在下游表现为含沙量高、花园口洪峰增值突出、洪峰流量沿程衰减较小等特点。分析认为造成花园口洪峰增值的主要原因是由于高含沙水流比前期清水水流阻力较小,使其流速大大快于前期的槽蓄水流的流速,在演进的过程中,不断“挤压”峰前的清水和部分前期槽蓄量,形成叠加。通过分析对今后高含沙洪水的研究、监测与调度等提出了建议。

Analysis of "2004·8" Flood in the Lower Reach of the Yellow River

In August 2004,there was a strong rainfall process in the middle reach of the Yellow River.According to the flood control scheme,high sediment concentration discharging was made by operating the Xiaolangdi Reservoir.When the flood traveled towards the river mouth,it had the characteristics of high sediment content,quite larger increase of peak discharge at Huayuankou Hydrologic Station and smaller decrease of peak discharge during propagation after the Huayuankou Station.After a series of investigation and analysis,it was thought that the main reason was the resistance of high sediment content was much smaller than that of its previous clear water,which had made the velocity much higher than its previous channel conveying flow.Thus,during the propagation downwards,the clear water and part of the previous channel storage water,which was in front of the peak,was continuously "squeezed" and a kind of piling up was formed.Through the analysis,the proposals were made for the future study,monitoring and regulation of the high sediment concentration flow.