长江口没冒沙演变过程及其对水库工程的响应

EVOLUTIONAL PROCESS IN MEIMAOSHA OF THE YANGTZE RIVER ESTUARY AND ITS RESPONSE TO RESERVOIR PROJECT

研究南槽没冒沙演变规律,可以为筑库引淡蓄水工程建设提供科学依据。根据该海区近百年来各个时期的海图和20年来的实测水文泥沙等资料以及2003、2004年的现场观测数据,探讨了没冒沙的形成及形成后的演变过程。研究表明:没冒沙的形成和发育经历了局部边滩冲刷、边滩沙嘴发育和沙脊形成3个阶段;近半个世纪来,沙体中轴位置在稳定强劲的涨落潮流作用下呈现出西北—东南走向的良好的稳定性,具有潮流脊性质。而蓄淡水库工程建设将有可能使南槽成为适应进出水沙量的新型河槽。

The understanding of evolutional process in Meimaosha in the south passage of the Yangtze River Estuary may provide scientific base for the construction of reservoirs along the river. According to data of charts and in-situ water and sediment change for about one hundred years, especially the recent field measures obtained in 2003 and 2004, the form history and evolutional process of the Meimaosha were discussed. The results showed that the formation and growth of Meimaosha had undergone three phases, i.e. the erosion of local beach, the growth of spitting and the formation of sand ridge. Meimaosha exhibited characters of tidal sand ridge as its middle axe had a good stability along the direction from northwest to southeast under the action of steady and driving flood and ebb tides in the passed half century. It is likely that the construction of the reservoir project will change the whole south passage to a new type watercourse suitable for water and sediment passing.