The Dinh An Estuary is one of the Nine Dragon estuaries of the Mekong River. An international navigation channel was built in the estuary for vessels traveling from the South China Sea to the southwestern area of Viet...The Dinh An Estuary is one of the Nine Dragon estuaries of the Mekong River. An international navigation channel was built in the estuary for vessels traveling from the South China Sea to the southwestern area of Vietnam and then to Phnom Penh, Cambodia. The morphological evolution of the navigation channel is complicated and unstable. The back siltation intensity in the navigation channel has largely increased and been concentrated in the curvature segments of the channel since 1980. In this study, based on simulation results and measured data, five key factors that influence the back siltation in the navigation channel were systematically analyzed. These factors included the increasing elevation gap between the channel and the nearby seabed, the disadvantageous hydrodynamic conditions, sediment transport, mixing of saltwater and freshwater, and wave effects in the navigation channel. It is shown that the back siltation to a large extent results from the low current velocity of the secondary ocean circulation, which often occurs in the curvature segments of the channel. Suspended sediment also settles in the channel due to the decrease of the current velocity and the sediment transport capacity when flow passes through the channel. The changes of hydrodynamic conditions are responsible for the majority of the severe siltation in the curvature segments of the navigation channel.展开更多
On the basis of a comparison of the field hydrological, sediment and topographic data observed before and after the completion of the West Breakwater in Lianyungang Harbor, which has led to the change of topography fr...On the basis of a comparison of the field hydrological, sediment and topographic data observed before and after the completion of the West Breakwater in Lianyungang Harbor, which has led to the change of topography from a strait to a bay, a synthetical analysis is conducted on the change of back siltation. The results show that it is the change of coast line and the consequent change of hydrological condition and sediment movement that has led to the change of back siltation in the harbor. This phenomenon is caused by the lag effects of water current, sediment movement and local adjustment of topography after the construction, and it tends to be stable. The results of analysis provide not only a basis for extension of Lianyungang Harbor into a deep water harbor, but also propose a case for the study of the change of back siltation in a harbor on muddy coast.展开更多
基金supported by the 322 Project of Vietnam International Education Development, Ministry of Education and Training, Vietnam (Grant No. 322)the Qing Lan Project, the 333 Project of Jiangsu Province (Grant No. BRA2012130)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No.2012B06514)the 111 Project (Grant No. B12032)
文摘The Dinh An Estuary is one of the Nine Dragon estuaries of the Mekong River. An international navigation channel was built in the estuary for vessels traveling from the South China Sea to the southwestern area of Vietnam and then to Phnom Penh, Cambodia. The morphological evolution of the navigation channel is complicated and unstable. The back siltation intensity in the navigation channel has largely increased and been concentrated in the curvature segments of the channel since 1980. In this study, based on simulation results and measured data, five key factors that influence the back siltation in the navigation channel were systematically analyzed. These factors included the increasing elevation gap between the channel and the nearby seabed, the disadvantageous hydrodynamic conditions, sediment transport, mixing of saltwater and freshwater, and wave effects in the navigation channel. It is shown that the back siltation to a large extent results from the low current velocity of the secondary ocean circulation, which often occurs in the curvature segments of the channel. Suspended sediment also settles in the channel due to the decrease of the current velocity and the sediment transport capacity when flow passes through the channel. The changes of hydrodynamic conditions are responsible for the majority of the severe siltation in the curvature segments of the navigation channel.
文摘On the basis of a comparison of the field hydrological, sediment and topographic data observed before and after the completion of the West Breakwater in Lianyungang Harbor, which has led to the change of topography from a strait to a bay, a synthetical analysis is conducted on the change of back siltation. The results show that it is the change of coast line and the consequent change of hydrological condition and sediment movement that has led to the change of back siltation in the harbor. This phenomenon is caused by the lag effects of water current, sediment movement and local adjustment of topography after the construction, and it tends to be stable. The results of analysis provide not only a basis for extension of Lianyungang Harbor into a deep water harbor, but also propose a case for the study of the change of back siltation in a harbor on muddy coast.
