黄河中游水利水土保持措施减沙作用研究的回顾与展望

Review of the effects researches of soil and water conservation on sediment reduction in the middle reaches of the Yellow River

黄河中游水利水土保持措施减沙关系黄河治理战略全局,对其进行回顾和展望,可为目前开展的黄河综合规划修编提供重要参考。结果表明:1960—1984年,平均每年拦蓄泥沙约5亿t,其中干流水库1.0亿t(19.6%)、支流水库1.2亿t(23.5%)、灌溉引沙0.6亿t(11.8%)、淤地坝拦沙2.0亿t(39.16%)、梯田拦沙0.3亿t(5.9%);到20世纪80和90年代,这种减沙构成略有变化,总体来看,水利措施减沙比例变化不大,而水土保持措施拦沙比例有所减小;70—90年代,黄河中游年均减沙3亿t左右,目前,水利水土保持措施现状减沙约3.5亿～4.5亿t。展望水利水土保持措施减沙作用后认为:近年来,黄土高原水土流失地区暴雨强度较小,实测来沙量资料不能作为黄河综合规划修编中水土保持现状减沙效果计算的主要依据;由于未来黄河中游来沙量变化取决于多种因素的组合,因此,对未来水利水土保持措施减沙作用应持慎重和偏于安全的态度,并作为今后长期认真研究的问题。

The effects of soil and water conservation on sediment reduction in the middle reaches of the Yellow River relate to the overall strategy of the river harnessing. Review of the effects researches of soil and water conservation on sediment reduction, therefore, has a significant reference value for the ongoing revision of comprehensive planning of the Yellow River. The studies of the role of water projects and soil and water conservation on sediment reduction have shown that about 510 million tons of sediment had been impounded each year during 1996 -2000, including 100 million tons （19.6%） impounded by reservoirs of the main stream, 120 million tons （23.5%） by reservoirs of tributary streams, 60 million tons（ 11.8% ） intercepted by irrigation system, 200 million tons （39.16%） by warping dams, and 30 million tons （5.9%） by terrace. This ratio of sediment intercepting had changed in the 1980＇s and 1990＇s, the proportion of sediment intercepting of water projects had changed a little, while the proportion of water and soil conservation had reduced. The studies also show that about 300 million tons of sediment was intercepted annually by water projects and water and soil conservation in the middle reaches of the Yellow River during the 1970＇s - 1990＇s, and the figure is 350 million -450 million tons now. To theeffects of water projects and soil and water conservation on sediment reduction, we consider that the storm intensity is decreased in the soil erosion area of the Loess Plateau in recent years, therefore the data of measured incoming sediment cannot be used as main basis in calculation of current sediment reduction effects of soil and water conservation in revision of comprehensive plan of the Yellow River. The main reason for this is that, the changes of incoming sediment in the middle reaches of the Yellow River depends on the combination of many factors. Therefore, the effects of soil and water conservation on sediment reduction should be studied from now on and for a long time.