摘要
Feiyan Shoal is a sub Yellow River Delta, which was formed from Jan. 1964 to May 1976, when the Yellow River entered sea via Diaokou Channel. Since the terminal reach shifted to Qingshuigou channel in 1976, Feiyan Shoal has been experiencing severe erosion and retreat. This paper explains the evolutionary characteristics of the typical profile of Feiyan Shoal from the perspective of dynamical force and sediments＇ characteristics. All this is on the basis of the data of topographic profiles observed since the 1970s and the samples of hydrology and sediments collected in situ in Apr. 2004, the analysis of the retreating distance, and the tidal and wave friction velocity distribution. Feiyan Shoal topographical profile has experienced a course of ＂fast erosion and retrogression - slow eroding modulation - fluctuate triggering change＂ in recent 30 years, which is also the gradual disappearing process of the delta front. The different intensity of sediment erosion resistance is the main reason for the erosion speed changes. Due to the hydrodynamic force changes, the water depth range of maximum retreating distance and between erosion and progradation became shallow. It indicates that the storm tide will still be the triggering force of seashore topographic profile evolutions in the future.
飞雁滩是1964年1月至1976年5月黄河尾闾由刁口流路入海形成的黄河亚三角洲。自1976年黄河改走清水沟入海后,飞雁滩岸滩发生强烈侵蚀后退。以20世纪70年代开始的地形固定断面观测资料、2004年4月现场水文泥沙及沉积物取样资料为基础,地形剖面后退距离作为统计参数,并根据实测资料计算了潮流和波浪底摩阻流速的横向分布,从动力分布和沉积物结构方面解释了飞雁滩典型剖面的变化特征。30 a来飞雁滩岸滩地形剖面经历了"快速后退侵蚀——慢速调整——波动触发"的变化过程,这也正是其三角洲前缘侵蚀逐渐消失过程。沉积物抗冲性强弱是剖面蚀退速度变化的主要原因,水动力条件的变化改变了不同阶段的地形剖面最大蚀退量水深范围与闭合深度。风暴潮仍是今后海滩地形剖面演变的触发动力。
基金
the Major State Basic Research Development Program of China(‘973’Program)(Grant No.2002CB412408)
the Shanghai Youth Science and Technology Venus(GrantNo.06QA14016).
