Sediment transport trends and cross-sectional stability of a lagoonal tidal inlet on the Central Coast of Vietnam

• Published in: International journal of sediment research Vol. 34; no. 4; pp. 322 - 334
• Main Authors: Duc, Do Minh, Tung, Tran Thanh, McLaren, Patrick, Anh, Tran Ngoc, Thi Quynh, Dinh
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2019; Faculty of Geology, VNU University of Science, Vietnam National University, Hanoi 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam%Faculty of Marine and Coastal Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam%SedTrend Analysis Limited, 7236 Peden Lane, Brentwood Bay, BC, Canada V8M1C5%Faculty of Meteorology, Hydrology and Oceanography, VNU University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam
• Subjects: Cross-sectional stability; Lagoon; Sediment Trend Analysis (STA); Tidal inlet; Tidal prism; Tidal prism; Sediment Trend Analysis (STA); Lagoon; Tidal inlet; Cross-sectional stability
• ISSN: 1001-6279
• DOI: 10.1016/j.ijsrc.2019.01.001

Lagoonal tidal inlets are a typical morphology of the Central Coast of Vietnam. Recently, navigation channels in these inlets have become increasingly threatened by siltation. This study analyses the relations between sediment distribution and transport trends (using the technique of Sediment Trend Analysis-STA®) in the lagoonal system of the De Gi inlet and then proposes appropriate countermeasures against sand deposition in the navigation channel. The STA identified three types of transport trends in the De Gi inlet, namely dynamic equilibrium, net accretion, and net erosion. Processes associated with the tidal prism have resulted in trends of sediment transport and deposition across the flood and ebb tidal shoals, which maintain a present cross-sectional area of about 1000 m2. However, longshore sediment transport from north to south resulting from northeast waves cause additional sand deposition in the channel. In addition, the effects of refraction associated with a nearby headland and jetty also increase sedimentation. These processes provide the main reasons for sediment deposition in the De Gi inlet. Short term and regular dredging helps to maintain the navigation channel. A system comprised of three jetties (north, south, and weir) is necessary to ensure the longterm cross-sectional stability of the navigation channel. [Display omitted]