Silt-Discharge Variation and Channel Response of the Lower Yellow River

The paper analyzes the silt-discharge variation and channel response of the lower Yellow River after completion of the three reservoirs of Longyangxia,Liujiaxia and Sanmenxia.It concludes that a) after putting into operation of Sanmenxia Reservoir,the discharge of flood season averages about 45% of the whole year proportion,reducing 15% comparing with the natural condition and the sediment ejection is more concentrated(more than 95% of the whole year),increasing about 10% comparing with the natural condition.The silt-discharge trends even more unbalanced;b) Flood is reduced in flood season,both the peak discharge and volume in peak period reduced and sediment concentration increased,forming heavy sediment with less runoff and;c) the function of bed-building of floods is notably weaken,reducing the river plane scale and section scale,reducing the effected range of scoring and deposition evolution to some extent,the channel deposition more concentrated in normal channel and the deposition of the main channel and newly formed floodplain resulted in the development of secondary elevated river.It suggests building a sediment regulation reservoir on the middle Yellow River while regulating water by existing reservoirs,achieving integrated regulation and control of the Yellow River silt-discharge,creating relative harmonious silt-discharge relationship and keeping the healthy life of the Yellow River.