黄河中游悬移质泥沙粒径与流域环境的关系

以黄河中游多沙粗沙区为研究区，在流域泥沙粒径、降雨、地面物质组成、地面形态、植被和高含沙水流等资料采集的基础上，采用“环境要素法”和多元回归分析来阐明泥沙粒径空间分异的机理。研究表明，随降雨不均匀系数的减小，断面最大含沙量的减小，流域内黄土覆盖面积的增大，以及植被盖度的增大和沟谷密度的减小，悬移质泥沙粒径趋于变细，反之，趋于变粗。其中，流域地面物质对泥沙粒径组成起最重要的控制作用，其次是植被，高含沙水流、沟谷密度和降雨影响作用相对较小。

Relations between Grain-size of Suspended Sediments and River Basin Environment in the Middle Yellow River

A set of data on the grain-size of suspended sediments and river basin characteristics has been collected from the first order tributaries of the Middle Yellow River. A systematic study on quantitative relationships between grain-size of suspended sediments and the characteristics of these basins have been made for those river basins by using statistical methods. The following conclusions can be drawn: Precipitation, surface material, drainage density, vegetation coverage and hyperconcentrated flows act as an important controlling factor on the grain-size of suspended sediments in the Middle Yellow River. The grain-size of suspended sediments increases with an increase in drainage density, the maximum suspended sediment concentration and unevenness of precipitation, and decreases with an increase in the percentage of loess and vegetation coverage. Multiple regression analysis has shown that surface material is the most important factor influencing the grain-size of suspended sediments, followed by vegetation, hyperconcentration and precipitation. The drainage density exerts minor influence on the grain-size of suspended sediments.