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在长江宜昌以上地区干支流各站径流和泥沙统计资料的基础上,作了三个方面的分析研究:输沙量的地区分布;输沙量年内分配和年际变化;输沙量的成因及变化趋势分析。输沙量的多寡取决于泥沙的产沙因子和输移泥沙的动力因子。我们依据这一基本概念,分析了我国重点产沙输沙和次严重产沙输沙地区的必然性。于是从实测资料的统计和泥沙输移量的成因两方面论证了金沙江和嘉陵江流域是长江上游两个重点输沙区域,而且又是我国次严重的水力侵蚀区。在我国无论是严重的和次严重的水力侵蚀区都是分布在全国400mm等雨量线两侧。因为这些地区既具备充分的沙源,又有足够的输移能力,这是最基本的原因。同样,泥沙的年内分配和年际变化也可从中得到清晰的认识。文中同时指出人类活动特别是现代化的人类活动,它一方面具有加速产沙、输沙能力,另一方面也可起到抑制产输沙的双重性作用,应予以十分重视。
Based on the statistics of runoff and sediment at stations of dry and tributaries in the above Yichang area of the Yangtze River, three aspects are analyzed and studied: the regional distribution of sediment discharge; the distribution and inter-annual variation of sediment load; the causes of sediment discharge And trend analysis. The amount of sediment to be transported depends on the sediment yield factors of sediment and the kinetic factors of sediment transport. Based on this basic concept, we analyzed the inevitability of key sediment transport and sediment transport areas in China. Therefore, from the statistics of the measured data and the origin of sediment transport volume, it is demonstrated that the Jinsha River and the Jialing River are the two major sediment transport areas in the upper reaches of the Yangtze River and are also the second most serious hydropower erosion areas in China. In our country, both the serious and the second serious water erosion areas are distributed on both sides of the national rainfall line of 400mm. This is the most basic reason why these areas should have sufficient source of sand and enough transport capacity. Similarly, the distribution of sediment during the year and interannual changes can be clearly identified. At the same time, the paper points out that human activities, especially modern human activities, have the dual role of accelerating sediment yield and sediment transport, and on the other hand, they can also play a dual role in controlling sediment transport and sediment discharge.