HU Chun-hong, ZHANG Zhi-hao (China Institute of Water Resources and Hydropower Research, Beijing 100048, China)
Abstract: Using the methods of field data analyses and theoretical study, the variation characteristic and mechanism of floodwater stage during the atrophy process of channel is researched in the Lower Yellow River. The results show that the lower channel atrophy seriously by reason of variation of flow and sediment of Yellow River since 1986. Incipient rising floodwater stage hoisted markedly, the swelling rate of floodwater stage increase evidently, and the stage of main channel and floodplain are inconsistent. The hoisting of incipient rising floodwater is due to aggradation of the main channel of the Lower Yellow River. The hoisting of incipient rising floodwater influences the rising extent of flood peak stage greatly. The Lower Yellow River has a wide channel with powerful adjusting function of cross section during the travelling of floodwater, which results in the suddenly rising and fiercely declining easy. Its infection can’t be ignored. Via by introducing the parameter θ of the swelling rate of floodwater stage, the relationship between θ and the width of main channel, the rough rate ratio of main channel and floodplain, the expelling sediment ratio are established. The results show that during the atrophy process of the Lower Yellow River channel, transporting sediment capability of channel decrease, river breadth become narrow by a long way, resistance of floodplain increase obviously, they are all bring on the increasing of swelling rate of floodwater stage. The theoretical study is based on Chezy formula, which proves that the swelling rate of floodwater stage have non-linearity relationship to the atrophy of channel. The more serious atrophy of the Lower Yellow River is, the bigger increasing extent of swelling rate of floodwater stage becomes.
Key words: Lower Yellow River, the atrophy of channel, 96.8 floodwater, incipient rising floodwater stage, swelling rate of floodwater stage
Published in: Journal of Hydraulic Engineering, Vol. 43, No. 8, 2012
