长江河口南汇嘴潮滩近期演变分析

Analysis on Recent Topography evolution of Nanhuizui tidal flat in Yangtze Estuary

南汇嘴潮滩位于长江口和杭州湾的交汇地带,受长江口和杭州湾北岸两股潮流的控制,近年来由于低潮滩促淤围垦工程导致其水流和泥沙运移、沉积和地貌发生了显著的变化。根据近期水文泥沙观测资料及1993年、1998年、2003年、2005年的实测地形图资料,分析了南汇嘴潮滩近期演变特征。研究结果表明:1993-1998年为淤涨期;1998-2003年为冲淤调整期;2003-2005年呈现向外淤涨的趋势。而造成这一趋势的原因主要包括潮滩海洋动力作用、长江入海泥沙变化及近岸海岸工程建设等。

Nanhuizui tidal flat is a transitional zone situated in a special area between the Yangtze estuary and Hangzhou Bay. It is controlled by two tidal current of the Yangtze Estuary and north shore of Hangzhou Bay. In recent years, the changes of sediment transport, sediment logical process and morphological evolution are notable Based on a great amount of hydrological and sediment data and the topographic maps of 1993, 1998, 2003 and 2005, it is discussed that the recent characteristics of topography evolution on Nanhuizui tidal flat. The results suggest that 1993--1998 is the period of coastal progradation; 1998--2003 is the period of coastal adjustment; while the year form 2003 to 2005, there is a tendency of resuming progradation. It is caused by the effect of the change of ocean dynamics, sediment flux to the sea and the constructions of some great coastal engineering projects.