Abstract:Two submerged breakwaters are intended to be built in the north branch of Hechangzhou waterway to improve the navigation conditions in the south branch.The proposed submerged breakwaters located in the deep channel of the river which makes the construction of the deep water zone difficult.In this paper,focused on a single upstream submerged breakwater,three different construction sequence plans “deep to shallow”,“shallow to deep” and “gradually raise” are studied,and the hydrodynamic conditions of each scheme changes at different stages of construction process are simulated and analyzed,based on a three-dimensional hydrodynamic numerical model.The results show that:On the premise that the construction difficulty has not been improved obviously in the construction area,especially the deep water area construction,“gradual raise” scheme has minimal impacts on the surroundings,especially the nearshore hydrodynamic environment during the construction process,which can be regarded as the recommended scheme.The results can provide reference for the quality control of construction such as riprap process.