黄河三角洲飞雁滩沉积物颗粒度分布和粒度参数特征及水动力解释

黄河三角洲飞雁滩因入海河口改道而缺乏泥沙来源,导致海滩蚀退10余km。近30a来,蚀退后的浅滩在不同潮流和风浪的作用下,浅海滩沉积物颗粒在空间分布上出现明显的差异,表现为浅水区沉积物粗于深水区,来沙少的沉积区粗于来沙多的沉积区。根据2004年实测沉积物颗粒度参数和实测水流及风浪资料分析,该海滩可以分为三个沉积区:I号沉积区,水深较浅,泥沙补给较少,主要受不同风浪的影响,沉积物颗粒组成较粗,以细砂和粉砂为主,分选良好,目前抗冲能力较强;II号沉积区,水深较浅,水流较弱,常受来自高中低潮滩下泄水流携带的细颗粒泥沙影响,沉积物组成粗细混合,以粉砂质粘土为主,分选较差;III号沉积区,水深大,在潮流和风浪作用下,常有来自沿岸尤其I号沉积区的细颗粒泥沙影响,沉积物组成粗细混合,以粘土质粉砂为主,分选较差。黄河三角洲飞雁滩桩106海滩沉积物空间分布较好地反映了泥沙来源和沉积动力条件,该成果可为海岸海滩防护工程规划设计提供科学依据。

Characteristic and Hydrodynamic Explanation of Distribution and Parameters of Sediment Granularity in Feiyan Shoal of Yellow River Delta

The Feiyan shoal of the Yellow River Delta is short of sediment source because of the rerouting of the Yellow River estuary, which caused the shoal to retreat about 10km. In the past 30 years, the sediment particles present the obvious differences in the space distribution due to the tidal current and storm waves affecting the shoals in 2004. To be more specific, the sediment particles in the shallow water zone are coarser than those in the deep water zone, and those in the zone with less incoming-sediment are coarser than in the zone with more incoming-sediment. The shoal is divided into three deposition zones according to the parameters of sediment granularity and the analysis of the data of the measured current and storm wave. In the first zone ,the water is relatively shallow, and there is less sediment supply. Affected by different storm waves, the grain composition of the sediment particles is coarse, and the majority of them are well-sorted fine sands. the erosion-resisting characteristic of the zone is strong. In the second zone ,the water is shallow and the current is weak. Affected by the fine sediments coming from the tidal shallows discharging, the sediment is poorly-sorted and composed of coarse and fine particles, and the majority of them are fine sandy clay. In the third zone, the water is deep. Affected by the tidal current and the storm waves, there are some influences resulted from the fine sediment particles coming from the barrier beach especially in the first zone. The sediment is poorly-sorted and composed of coarse and fine particles, and most of them are fine clay sands. The space distribution of the sediment shows the source of the sediment and the deposition dynamic conditions in the Feiyan shoal of the Yelllow River delta, which can offer reference for the relative study.