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我国是一个多沙河流的国家。黄河是世界上罕有的多沙河流。在黄河中游流域面积58万平方公里内,分布有四十多万平方公里的黄土高原,土质松散,极易遭受侵蚀。在一些沟谷地区,年平均侵蚀模数多在15000吨/平方公里以上,最大可达34000吨/乎方公里。多年平均年产沙总量超过16亿吨,平均含沙量达37.6千克/立方米,居世界首位。流域产沙是江河湖库及沿海泥沙的主要来源,另一方面由于流域上的土壤侵蚀,大量的水土流失,肥力降
My country is a country with many rivers. The Yellow River is a rare sandy river in the world. In the middle reaches of the Yellow River basin area of 580,000 square kilometers, the distribution of more than 400,000 square kilometers of Loess Plateau, loose soil, vulnerable to erosion. In some valleys, the annual average erosion modulus is more than 15,000 tons per square kilometer, up to 34,000 tons per square kilometer. The average annual output of sand in many years has exceeded 1.6 billion tons with an average sediment concentration of 37.6 kg / m3, ranking first in the world. Sediment production in rivers and lakes is the main source of sediments in rivers and lakes and coastal areas. On the other hand, due to soil erosion, large amounts of water and soil loss,