HU Chunhong, ZHANG Zhihao

Abstract: In this paper, the relationship between the critical threshold of equilibrium sediment transport in the Yellow River and soil erosion control in the Loess Plateau is studied by using the observed data analysis and theoretical analysis. The results show that, the critical threshold of the balance sediment transport in the Yellow River is changed with the changes of flow and sediment conditions in different periods. In the next stage, the critical threshold of equilibrium sediment transport in the Ningmeng reach is about 40 million t/a; and the critical threshold of equilibrium sediment transport in the middle and lower reaches of the Yellow River and its estuary is about 300 million t/a. Through water and sediment regulation and river regulation, the annual sediment transport volume of Ningmeng reach will be controlled at about 40 million t/a in the future. The channel for water and sediment transport can be built and maintained with a bank flow of about 2000m3/s. The balance of scour and silt can be basically realized in Ningmeng reach. By controlling the annual sediment transport of the middle and lower reaches of the Yellow River and its estuary at about 300 million t/a, it can basically realize the rise and fall balance at the Tongguan elevation, which is stable at about 328 m. The lower reaches can shape and maintain the channel of water and sediment transport around the bank flow of about 4000 m3/s, and basically realize the balance of scour and silt. The estuary basically realizes the balance of erosion and silt and remains relatively stable. There is also a critical state that the effect of soil erosion control on the Loess Plateau is not significant after it reaches a certain degree, show that the soil erosion control on the loess plateau exist management degrees. In view of the loess plateau soil and water loss control measures of critical threshold, this paper puts forward the future through scientific adjustment of the loess plateau governance pattern, to control the sediment quantity of entering into the Yellow River about 300 million t/a, achieving the balance of the sediment transport in the main stream of the Yellow River and the degree of soil erosion control on the Loess Plateau, and the target of soil erosion control in Loess Plateau is determined.

Keywords: Yellow River channel; Loess Plateau; critical threshold; balanced sediment transport; soil erosion control