滦河流域水库对河流表层沉积物粒度空间分布影响的研究

Spatial Distribution Characteristics in Grain Size of River Surface Sediments Under the Influence of Reservoirs in the Luanhe River Basin

分析沉积物粒度空间分布规律对于揭示水库的修建对河流污染物沉积和分布的影响具有重要意义。根据海拔高度与河流走向的关系,在滦河干流与支流采集75个表层沉积物样品,对平均粒径、分选系数、偏度系数、峰度系数和粒径差进行分析。结果表明:滦河干流平均粒径为142.3μm,分选系数3.86,偏度系数0.31,峰度系数1.26;滦河支流平均粒径为208.2μm,分选系数2.86,偏度系数0.39,峰度系数1.25;滦河干流和支流沉积物平均粒径在上中下游差异显著,干流下游(237.1μm)>上游(153.3μm)>中游(71.4μm);支流下游(531.1μm)>上游(60.7μm)>中游(42.4μm);显示出沉积物沿程粗化的空间分布规律;滦河干流与支流沉积物平均粒径之间差异显著,支流(208.2μm)>干流(142.3μm);水库对表层沉积物组分、分选性、偏度和峰度影响显著,水库规模与坝下和坝上沉积物的平均粒径差值呈正相关;建议水资源管理部门加强对河流表层沉积物粒度的监测与分析。

The Luanhe River is located in northern part of the Haihe River Basin, China. It is an important water source for industry and agriculture in Beijing, Tianjin and Hebei Province. The present study is to investigate the influence of reservoirs on the spatial distribution characteristics in grain size of surface sediments in the Luanhe River. Seventy-five surface sediment samples were collected from the Luanhe River and its main tributaries. Sediments grain size parameters,which included average particle size, Sorting coefficient, Skewness, Kurtosis and degree of average particle size,were measured by a laser particle analyze. Results showed that the average particle size of surface sediments in the upstream of the Luanhe River or its tributaries was significant different from that in the downstream, demonstrating an obvious trend in terms of surface sediment grain coarsening from upstream to downstream. Furthermore, the size of reservoirs had positive relationship with the degree to which the average particle size of sediment at upstream was different from that at downstream of reservoirs. Our hypothesis was that the twenty-nine large and medium size reservoirs had tremendous impacts on the distribution characteristics in surface sediment grain sizes in the Luanhe River and its tributaries. This study provided fundamental information on the environmental conservation,ecological restoration, and water management of the Luanhe River Basin.