Vu Duy Vinh


With the area of only about 700 ha, Nai lagoon has a great contribution to ecology as well as socioeconomic development of Ninh Hai disctrict and Phan Rang-Thap Cham city (Ninh Thuan province). However, the deposition tendency has occurred recently, making the lagoon shallower. It also causes the decrease in water exchange as well as environmental degradation in this area. Therefore, solutions that increase water exchange and reduce the deposition rate in the Nai lagoon are necessary. Based on the Delft3D model with MORFAC approach, this paper gives some assessments on the impact of coastal engineering solution on water exchange and sediment transport. The simulation scenarios include as extending present jetties to 165 m long, extending present jetties combined with dredging lagoon inlet, extending only northeast jetty to 260 m long combined with dredging lagoon inlet, and dredging all lagoon area. The results show that the change in water exchange is very small (almost below 1%), except in the case of dredging the entire lagoon area, water exchange decreases about 10% (due to the increase of the lagoon water volume) compared with the present. Sediment flux balance at cross-section MCI (Tri Thuy bridge) also changes slightly under influence of coastal engineering works. On the other hand, sediment flux from the coastal zone into the inlet (cross-section 2- MCII) and alongshore to Southwest (cross-section MCIII) have strongly decreased. Especially, in the scenario of extending northeast jetty combined with and dredging the inlet zone, net sediment flux into the inlet decreases from 637 m3/day to 180 m3/day (droughty year) and from 535 m3/day to 80 m3/day in the flood year.


Nai lagoon, coastal engineering, water exchange, sediment transport, MORFAC, Delft3D.


Lesser, G. R., Roelvink, J. V., Van Kester, J. A. T. M., and Stelling, G. S., 2004. Development and validation of a three-dimensional morphological model. Coastal engineering, 51(8-9), 883-915.

Roelvink, J. A., 2006. Coastal morphodynamic evolution techniques. Coastal Engineering, 53(2), 277-287.

Lesser, G. R., 2009. An approach to medium-term coastal morphological modelling. UNESCO-IHE, Institute for Water Education, ISBN 978-0-415-55668-2.

Tonnon, P. K., Van Rijn, L. C., and Walstra, D. J. R., 2007. The morphodynamic modelling of tidal sand waves on the shoreface. Coastal Engineering, 54(4), 279-296.

Jones, O. P., Petersen, O. S., and Kofoed-Hansen, H., 2007. Modelling of complex coastal environments: Some considerations for best practise. Coastal Engineering, 54(10), 717-733.

Dissanayake, D. M. P. K., Ranasinghe, R., and Roelvink, J. A., 2009. Effect of sea level rise in tidal inlet evolution: A numerical modelling approach. Journal of Coastal Research, 942-946.

Van der Wegen, M., and Roelvink, J. A., 2008. Long‐term morphodynamic evolution of a tidal embayment using a two‐dimensional, process‐based model. Journal of Geophysical Research: Oceans, 113(C3). Doi:10.1029/2006JC003983.

Van der Wegen, M., Wang, Z. B., Savenije, H. H. G., and Roelvink, J. A., 2008. Long‐term morphodynamic evolution and energy dissipation in a coastal plain, tidal embayment. Journal of Geophysical Research: Earth Surface, 113(F3). Doi:10.1029/2007JF000898.

Vũ Duy Vĩnh, Trần Đình Lân, Trần Anh Tú, Nguyễn Thị Kim Anh, Nguyễn Ngọc Tiến, 2016. Ảnh hưởng của các quá trình động lực đến biến động địa hình đáy vùng ven bờ cửa sông Mê Kông. Tạp chí Khoa học và Công nghệ biển, 16(1), 32-45.

Duy Vinh, V., Ouillon, S., Van Thao, N., and Ngoc Tien, N., 2016. Numerical simulations of suspended sediment dynamics due to seasonal forcing in the Mekong coastal area. Water, 8(6), 255.

Vũ Duy Vĩnh, Đỗ Thị Thu Hương, Nguyễn Văn Quân, Nguyễn Ngọc Tiến, 2016. Đặc điểm vận chuyển bùn cát và nguyên nhân gây bồi lắng khu vực đầm Nại (Ninh Thuận). Tạp chí Khoa học và Công nghệ biển, 16(3), 283-296.

Jones, M. T., Weatherall, P., and Cramer, R. N., 2009. User guide to the Centenary Edition of the GEBCO Digital Atlas and its data sets. Natural environment research council.

Lyard, F., Lefevre, F., Letellier, T., and Francis, O., 2006. Modelling the global ocean tides: modern insights from FES2004. Ocean Dynamics, 56(5-6), 394-415.

Boyer. T, Ed.; A. Mishonov, 2013. Technical Ed.: World Ocean Atlas 2013 Product Documentation. Ocean Climate Laboratory, NODC/NESDIS/NOAA. Silver Spring, MD 20910-3282.

Hydraulics, D., 2014. Delft3D-FLOW User Manual: Simulation of multi-dimensional hydrodynamic flows and transport phenomena, including sediments. Technical report.

Argoss, B. M. T., 2011. Overview of the service and validation of the database waveclimate. Reference: RP_A870.

Battjes, J. A., and Janssen, J. P. F. M., 1978. Energy loss and set-up due to breaking of random waves. In Coastal Engineering 1978 (pp. 569-587).

Schneider, V. R., and Arcement, G. J., 1989. Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Flood Plains. Available from the US Geological Survey, Books and Open-File Reports Section, Box 25425, Federal Center, Denver, CO 80225-0425. Water-Supply Paper 2339, 1989. 38 p, 22 fig, 4 tab, 23 ref.

Simons, D. B., and Şentürk, F., 1992. Sediment transport technology: water and sediment dynamics. Water Resources Publication.

Uittenbogaard, R. E., 1998. Model for eddy diffusivity and viscosity related to sub-grid velocity and bed topography. Note, WL|Delft Hydraulics.

Van Vossen, B., 2000. Horizontal large eddy simulations; evaluation of computations with DELFT3D-FLOW. Report MEAH-197. Delft University of Technology.

Van Rijn, L. C., 1993. Principles of sediment transport in rivers, estuaries and coastal seas (Vol. 1006). Amsterdam: Aqua publications.

Vũ Duy Vĩnh, Nguyễn Văn Quân, 2015. Đặc điểm thủy động lực và khả năng trao đổi nước khu vực đầm Nại (Ninh Thuận) - kết quả từ mô hình Delft3D. Tạp chí Khoa học và Công nghệ biển, 15(3), 250-256.

Rijn, L. C., 1998. Principles of coastal morphology. Aqua Publications.

Sivester, R., and Hsu, J. R. C., 1993. Coastal Stabilization: innovative concepts.

Kieslich, J. M., 1981. Tidal Inlet Response to Jetty Construction (No. WES-GITI-19). Army engineer waterways experiment station vicksburg MS.

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