浙南巴艚港水沙变化及对水道冲淤影响分析

The Change of Dynamics and Concentration and Their Influence on the Erosion and Deposition in the Bacao Bay,South Zhejiang,China

在巴艚港水沙和冲淤特性分析的基础上,指出潮流对进出港水道泥沙的冲淤起决定性作用,风浪仅影响浅海泥沙起动和含沙量过程,径流集中在梅雨和台风雨季节,能加强巴艚港落潮流作用。巴艚港外水域冲淤基本平衡,港内水道略冲,两侧潮滩微淤。鳌江江南潮滩围垦后,巴艚港琵琶门断面纳潮量减少53.6%,落潮水体含沙量降低至工程前的1/16,水流挟沙力和含沙量同步下降,水道仍将保持工程前冲淤特性。

The characteristics of the dynamics and concentration and the erosion and deposition in the Bacao Bay are analyzed. The tidal current is the main dynamics for the sediment erosion and deposition. The waves have a little influence on the sediment erosion in the shallow waters. The runoff only strengthens the ebb tidal current during the flood season in the Bacao Bay. It is suggested that the channel bed is eroded and the tidal flat besides the channel accumulates in the Bacao Bay and the waters out of Bacao Bay is in balance. According to plan, a dyke will be built in the northern tidal flat of Bacao Bay when the exchange of water and sediment between the tidal flat and the bay will be cut off. Compared with those before the dyke is built, the tidal prism will be 50% and the concentration of water will be 10 % in the Bacao Bay. The result is that both of the sediment holding ability and the sediment concentration reduce and their balance maintains after the dyke is built. The evolutionary characteristics of Bacao Bay will remain almost the same.