浙闽淤泥质港湾的基本特征

The Basic Feature of Muddy Bay in Zhejiang and Fujian Provinces

浙闽淤泥质港湾是我国重要的海岸类型。潮波传播过程中受到地形制约，具有驻波特性，潮差大，潮流急。港湾处于隐蔽条件下，湾顶潮滩和港汊广泛发育。本文在1991—1992年野外调查、浅滩水文测验和前人研究的基础上，从动力、沉积和地貌的角度出发，对潮波基本特征、潮滩沉积模式和港湾稳定指标作出新的概括和发展，为港湾综合开发提供依据。

There are more than ten muddy bays such as Sanmen Bay, Leqing Bay, ShachengBay and Sandu Bay along the Zhejiang and Fujian provinces from the north to the south. Inthese areas the tidal range is large, and the tidal current is strong. The propagation is possessedof tidal wave the character of stand wave. Tidal wave is controlled by geometric contour of thebays. From the bay mouth to the top of the bay, the tidal range is gradually increased. The maximum there reaches to more than 8 m. In general, the flood duration is longer than the ebb oneand the flood velocity is less than the ebb one. Channel is the better depth in the bay. The bay islocated in the hidden conditions where the wave is week and the tidal flats in the top of the bayare developed well. The dynamic mechanics is that during flood the water toward the flatsmoves slowly and the sediments disperse toward the flats and deposit on it, and during ebb thevelocity of the water toward the channel is larger and sediments carried by water are dischargedinto the channels. In this situation the materials of the tidal flats in the bay are finer and the sorting is poor. There is no obviously bedding structures in the tidal flats and they extend outwardliking tongue. In the muddy bays of the Zhejiang and Fujiang provinces, the sediment resourcesare affected by the deposition of the sediments from the Changjiang Estuary, but the quantity islower. In the most bays, the sediment transportation is basically in balance. So the bays, inwhich the ration between the square of the tidal flats and the whole square of the bay rangesfrom 0.4 to 0.6, belong to ones where the scouring and deposition occured not obviously.