长江口北港河势演变及趋势分析

Processes of North Channel and tendency analysis of the Yangtze Estuary

根据长江口1977-2013年海图及2011-2012年北港洪枯季实测水沙、流速数据,结合历史资料对北港上、中、下三段南北港分流口、北港主槽、拦门沙河段的河势演变进行分析。结果表明:20世纪70至80年代南北港分流口河道更迭演变是导致北港河势变化的主要原因;1977-2001年为北港主河槽的调整期,河槽上段北偏,下段南偏;涨潮流导致北港北沙淤涨,且北港北汊分流比增多;目前北港洪、枯季落潮优势明显;洪季落潮输沙明显,枯季涨潮输沙较强;由于大量河口工程的建设,北港河势进入稳定期,适宜航道开发。

Based on the nautical chart from 1977 to 2013 and the observed data such as sediment concentration and velocity in North Channel of the Yangtze River Estuary,and combined historical date,the evolution of south-north passage distributary and main channel of the North Channel and the upper reach of mouth bars in the North Channel are analyzed. Analysis results show that the main reason of river regime processes is the evolution of south-north passage distributary between 70‘s and 80＇s. It is the adjustment period of the main river between 1977 and 2001,the upper reaches of the north side and the under of section reach to the South.The flood current caused sediment deposition in the North Sand of the North Channel. The more diffluence in the North inlet of the North Channel,the more significant advantage of ebb tide in the North passage at present. Sediment transport during the flood tidal stage is in dry season and during the ebb tidal stage in flood season due to the construction of large number of estuarine engineering. The North Channel is in stability period.It is suitable for the development of waterway.