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本文通过黄河头道拐站1950-2009年水沙年系列进行突变点分析,识别出1969年、1986年、1996年3个突变点,将黄河内蒙古段水文过程划分为4个时期。在此基础上,利用内蒙古段6个水文站长系列日流量、日含沙量及泥沙组成数据,划分了各站的夏汛洪峰,并统计分析了分期洪峰的水沙分布特征和洪峰水沙关系,揭示出夏汛洪峰流量和输沙率逐渐减少的规律:1996-2006年与1954-1968年相比,夏汛洪峰水沙量占全年水沙的比例都减少了约一半,流量级频率与输沙率乘积的峰值对应的流量也降低了约一半。分析认为,黄河内蒙古段夏汛洪峰特征阶段性变化既有大型水库的影响,又有气候变化及人类活动的影响,而且后者的作用越来越大。分析发现,20世纪90年代以前,黄河上游水沙变化只是改变了内蒙古段来沙中粗颗粒泥沙的水沙关系,显示出大流量输送粗颗粒泥沙能力相对增强的趋向;进入内蒙段后,通过泥沙冲淤调整,分粒径组泥沙水沙关系变化比较复杂。近期在水沙条件巨大变化下,河流的输沙特性并没有发生根本变化,但是无论全沙还是分组沙,水沙关系曲线变陡,大流量输送泥沙能力相对增强。
Based on the analysis of abrupt change points of the Yellow River Daoqu Shui station from 1950 to 2009, three change points were identified in 1969, 1986 and 1996, and the hydrological process in the Inner Mongolia section of the Yellow River was divided into four periods. On this basis, the daily flood volume, daily sediment concentration and sediment composition data of 6 hydrological station owners in Inner Mongolia were used to divide the summer flood peak of each station, and the statistical analysis was made of the distribution characteristics of flood and sediment in flood peak and flood peak water The relationship between flood peak discharge and sediment transport rate of summer flood season is revealed. Compared with 1954-1968, the proportion of summer flood flood and sediment discharge in the whole year is reduced by about half, The flow rate corresponding to the peak of the product of the stage frequency and the sand transport rate has also been reduced by about half. According to the analysis, the phased changes of flood peak characteristics of summer flood season in Inner Mongolia of the Yellow River are affected by both large reservoirs and climate change as well as human activities, and the latter is playing a more and more important role. The analysis shows that before the 1990s, the change of water and sediment in the upper reaches of the Yellow River only changed the relationship between the water and sediment of the coarse sediment in the sediment in Inner Mongolia, and showed the tendency of the coarse sand and sediment in the heavy flow being relatively enhanced. Through the adjustment of sediment erosion and sedimentation, the relationship between sediment, sediment and sediment in the sub-particle size group is more complicated. Recently, under the great changes of water and sediment conditions, the sediment transport characteristics of rivers have not changed fundamentally. However, both the whole sand and the group sand have a steep curve and the capacity of transporting large amounts of sediment is relatively enhanced.