论黄河河道平衡输沙量临界阈值与黄土高原水土流失治理度

本文采用实测资料分析与理论分析相结合的方法,系统研究了黄河干流河道平衡输沙量临界阈值及其与黄土高原水土流失治理程度的关系,结果表明,黄河河道冲淤平衡输沙量临界阈值是随着不同时段来水来沙条件的变化而变化的。今后一个时期内,黄河上游宁蒙河段平衡输沙量临界阈值为0.4亿t/a左右;黄河中下游河道及河口平衡输沙量临界阈值为3亿t/a左右。通过水沙调控和河道整治等综合措施,未来将黄河上游宁蒙河段年输沙量控制在0.4亿t/a左右,可塑造与维持平滩流量约2000 m~3/s左右的输水输沙通道,宁蒙河段基本实现河道冲淤平衡;将黄河中下游河道及河口年输沙量控制在3亿t/a左右,则潼关高程可基本实现升降平衡,稳定在328 m左右,下游河道可塑造与维持平滩流量4000 m~3/s左右的中水河槽,基本实现河道冲淤平衡;河口基本实现海岸淤蚀平衡,保持流路相对稳定。黄土高原水土流失治理也存在达到一定程度后治理效果不显著的临界状态,表明黄土高原水土流失治理存在治理度,针对黄土高原水土流失治理各种措施减沙的临界阈值,本文提出未来通过科学调整黄土高原水土流失治理格局,将入黄年沙量控制在3亿t/a左右,达到黄土高原水土流失治理程度与黄河干流河道输沙的平衡,为未来黄土高原水土流失确定了治理目标。

Discussing of the critical threshold of equilibrium sediment transport in the Yellow River and the degree of soil erosion control in the Loess Plateau

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 theobserved 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 Ningmengreach 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 Ningmengreach 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 Ningmengreach. By controlling the annual sediment transport of the middle and lower reaches of the Yellow River and its estuary atabout 300 million t/a, it can basically realize the rise and fall balance at the Tongguanelevation, 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.