闽江口川石水道的水文泥沙特性及其内拦门沙成因分析

闽江口川石水道,口内段落潮流占优势,口外段涨潮流占优势,口门附近是落潮流优势向涨潮流优势转化的过渡地带.由于水流分汊、分歧、扩散、会潮以及盐淡水混合等因素的作用,口门附近水动力条件较弱.该水道在中潮位以下的低水时期泥沙运动活跃,河槽冲淤变化剧烈. 在川石水道的口门上发育着拦门沙,堆积体部分处在口内,部分处在口外,两部分堆积体虽然相连,在外形上是一整体,并统称为内沙浅滩,但是口内外堆积体的形成发育过程有明显的差别.川石水道口门上的拦门沙实原上是由不同原因造成的两个浅滩的联合体.

Analysis on the Hydrographic Factors, Sediments Features and Origin of the Inner Mouth-Bar of the Chuanshi Channel in the Minjiang River Mouth

There is a transition zone where the ebb current changes into the flood current in the Chuanshi Channel of Minjiang River mouth while the ebb current is dominant in the inner reach of the mouch and the flood current is dominant in the outer reach of the mouth.The hydrodynamic conditions are weaker near the mouth due to factors of bifurcation, divergence, tide meeting and mixing of saltwater and Fresh water.The sediment movement is active and the erosion-accretion variation is severe below the middle tidal level.The mouth-bar develops in the mouth of Chuanshi Channel.A part of the accumulated body is situated at the inner of the mouth and its another part is located at the outside.The both parts look like asa whole and are referred to as Neisha shoal since they are connected but their formation and evolution processes have obvious differences.The mouth-bar at the mouth of the Chuanshi Channel are essentially a united body of two shoals caused by different reasons.