黄河中游地区侵蚀产沙规律及水保措施减洪减沙效益研究综述

 黄河中游的粗泥沙主要来源于河龙区间(河口镇至龙门)以及泾、洛、渭等几条支流,粗沙来源区与多沙来源区基本一致,形成所谓的多沙粗沙区。黄河中游多沙粗沙区面积为7.86万km2,以22.8%的面积产生了69.2%的总输沙量和772%的粗泥沙量。黄土丘陵沟壑区一副区的土壤侵蚀模数最高,达1万2420～3万6440t/(km2 ·a)。水土保持措施(梯、林、草、坝等)起到了很好的减洪减沙作用。多项有关河龙区间的研究成果(水文法)表明:20世纪70年代,水土保持措施年均减沙量为2.08亿～2.75亿t,80年代为3.20亿～4.48亿t,90年代(1990—1996年)为3.16亿t。泾河、洛河、渭河等支流,水土保持措施的减洪减沙效益也十分突出。森林植被通过林冠层、枯落物层和根系土壤层的分层拦截吸收,起到突出的减洪减沙作用。晋西、陇东等试点流域,人工林区与无林或少林区相比,减沙效益高达78%～96%,消除了洪峰流量及猛涨猛落的洪水过程,从根本上控制了土壤侵蚀。今后,应加强不同尺度流域间,水沙运移规律的尺度转换等有关研究。

Rules of Erosion & Sediment Yield and Benefits of Flood & Sediment Reduction of Soil and Water Conservation Measures in the Middle Reaches of the Yellow River

The course sands in the middle reaches of the Yellow River are mainly from the reach from Hekou to Longmen, Jinghe River, Luohe River, Weihe River, etc., and the source of course sands areas and strong erosion areas happen to be in the similar areas, that is, the so-called areas of course sands and strong erosion (ACSSE). The ACSSE covers an area of 78600km², producing 69.2% of the total sediment and 77.2% of the total course sediment with only 22.8% of the total basin areas. The soil erosion module in sub-region one of the gully and hilly region of the Loess Plateau appears largest from 12420 to 36440t/(km²·a) contrasted with other areas. The measures of soil and water conservation including terraced fields, forestland, grassland, dam, etc., have played good functions in reducing flood and sediment. The results on study in reach from Hekou to Longmen show that the annual reduction of sediment of soil and water conservation measures is from 0.208 to 0.275 billion tons in the 80' of the 20th century, and from 0.320 to 0.448 billion tons in the 90', 0.316 billion tons from 1990 to 1996, through the hydrological method. The functions and benefits of that in Jinhe River, Luohe River, and Weihe River are all prominent. Through the roles of interception and absorption of the canopy layer, litter layer, and root and soil layer, the benefits of flood and sediment reduction of forest vegetation are prominent. Contrasted with neighboring non-forest or less-forest areas basin, the sediment reduction rates get to 78%～96% in a lot of experimental basins with the artificial forest in Western Shanxi and Eastern Gansu, etc., diminishing the strongly changing flood disasters and controlling the soil erosion radically. Further study on scaling of variation of flood and sediment in different scale basins should be strengthened henceforth.