中文摘要：

依据1977年至2011年6个不同年份的实测地形资料,从纵向变化和横向变化两个方面分别阐述了长江口如皋沙河段近期的河演过程.在此基础上,结合相关水文资料,建立了澄通河段二维潮流数学模型,复演了与上述6个年份地形相适应的涨落潮水动力过程.基于数模结果,对如皋沙河段的河演动力机制进行了分析和讨论.结果表明,如皋沙各汊道分流比和落潮平均流速与横断面面积密切相关,该河段的河演过程主要受落潮流控制;如皋沙右汉浏海沙水道主流顶冲点有逐步下移的趋势,有必要对该水道北岸的横港沙进行整治,以稳固该河段的基本河势.

英文摘要：

On the basis of 6 - year of measured terrain data from 1977 to 2011, near - term fluvial process of Rugaosha reach in the Changjiang River Estuary was analyzed from vertical and transversal variation. And then, combining with relevant hydro- logical data, we reproduced the hydrodynamic processes of flood and ebb with the six topography data by the 2D tidal flow mathe- matical model established for Chengtong reach; based on the numerical model results, the riverbed evolution of Rugaosha reach and its dynamic mechanism were analyzed and discussed. The research results show that, the spilt ratio and average ebb current at each branch has a good correlation with its cross - sectional area, which indicates that the riverbed evolution is mainly con- trolled by the ebb current. It is found that the apex of mainstream of Rugaosha in the Liuhaisha waterway moves downstream grad- ually, thus it is necessary to carry out some regulation projects on Hengansha to stabilize the river regime in the study area.