黄河干流悬移质泥沙粒径构成变化分析

Analysis of Grainsize Composition of Suspended Sediment of the Yellow River

根据黄河干流6个水文站的泥沙数据,采用时间序列统计分析方法,分析了1950s—1986、2002—2010年黄河悬移质泥沙粒径的时空变化特征,并探讨了人类活动对悬移质泥沙粒径变化的影响。结果表明:在黄河各水文站年输沙量均显著减少的状况下,各水文站悬移质的年中值粒径变化趋势并不一致,兰州、龙门、潼关、花园口站呈减小趋势,而头道拐、利津站则呈增大趋势;在年内,兰州站的悬移质泥沙月中值粒径变化波动减弱,而头道拐站的增强,龙门、潼关、花园口、利津站月中值粒径变化曲线具有同步性,月中值粒径最大值随时间推移不断增大;在悬移质泥沙组成中,头道拐、龙门、利津站的细、中、粗沙量占全沙比例有所变化,但各分组沙量与全沙量在不同时期仍保持线性关系,泥沙组成规律未发生明显变化;人类活动中,水土保持工程措施、大型水库修建等是影响悬移质泥沙粒径变化的主要因素。

Based on sand data of six hydrological stations in the main Yellow River, this paper analyzed the spatial and temporal variation characteristics of grain size of suspended sediments during 1950s to 1986 and 2002 to 2010. The results show that in the case of significant reduction of sediment loads, yearly median particle diameter of Lanzhou, Longmen, Tongguan and Huayuankou stations shows decreasing trend, Hekouzhen （Toudaoguai） and Lijin stations show increasing trend. Changes of the monthly median particle diameter are different in the six stations. Monthly median particle diameter of Lanzhou Station becomes smooth, Hekouzhen Station becomes sharp, the others are synchronous and monthly median particle diameter of peak values increases with time. The relationship between the group sediment and total load is consistent, which shows that the law of sediment composed has not changed in trend. In summary, the change of grain size of suspended sediment is mainly caused by water and soil conservation and building of reservoirs on the mainstream.