杭州湾北岸高潮滩沉积与沿岸物质输运趋势

TIDAL FLAT SEDIMENT CHARACTERISTICS AND TRANSPORT TRENDS ALONG THE NORTHERN BANK OF HANGZHOU BAY

根据对杭州湾北岸高潮滩上采集的沉积物样品的粒度分析,该处沉积物类型以粉砂为主,分选性、偏态和峰态分别属较差、正偏和宽峰,呈现明显的强潮高能潮滩特征。用Gao-Collins模型进行了粒径趋势分析,结果表明:海盐附近和芦潮港以东附近均向西输运,乍浦和拓林之间向东输运。对比近岸余流方向后发现,沉积物沿岸输运趋势与近岸的余流方向较为一致,这是由于作为高潮滩堆积细颗粒沉积物的主要来源的近岸水体中,悬浮沉积物的净输运是受余流控制的。

During November 2004, surficial sediment samples were collected from the upper part of the tidal flat on the northern bank of Hangzhou Bay. Grain size analysis of the samples, using a Mastersize2000 layer particle sizer, shows that the major constituent of the sediment is silt, with the mean grain size mainly between 5 and 6.5 Ф. The other grain size parameters, i.e. sorting coefficient, skewness and kurtosis, are indicative of the deposit formed in a high energy tidal environment. The sediment is poorly sorted and positively skewed, with a broad kurtosis. Results from the Gao-Collins model for grain size trend analysis show that the sediment transport is directed to west near Haiyan and Luchao Port, but to east between Zhapu and Tuolin. Compared with the residual current patterns in the adjacent waters, the transport trend along the northern bank has the same direction as the residual current. This agreement is related to the inherent relationship between suspended sediment transport and residual currents in this estuarine system, which provides suspended sedimentary materials to the tidal flat.