Qimiao Lu, Robert B. Nairn


Dredged pits in coastal zones are generally required for sand borrows for beach nourishment. The morphological response of borrow pits is important to evaluate future environmental impacts and potential impacts to adjacent seabed infrastructure such as pipelines. This paper will present the development of a simple concept model for the prediction of morphological response of dredged pits. A 3D hydrodynamic and sediment transport model was applied to verify the developed simple concept model. The case study for a sand-borrow pit on the offshore of Louisiana at the Atlantic coast of USA will be updated. The strengths and limitations of the developed model will be also discussed.


sand-borrow pits; sedimentation; margin erosion; sediment transport modeling; morphological modeling; empirical formulae

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Havinga, F.J., 1992. Sediment concentrations and sediment transport in case of irregular non-breaking waves with current. Report H480. Delft Hydraulics, Delft, The Netherlands.

Liu, J.J. and J.C. Zhang, 1983. Siltation study of some extension projects of the Lianyun Harbor, Int. Conf. On Coastal and Port Engineering in Developing Countries, Colombo, Sri Lanka, p1139-1147

Lu, Q. and Wai, O.W.H., 1998. An Efficient Operator Splitting Scheme for Three-dimensional Hydrodynamic Computations, International Journal of Numerical Methods in Fluid, 26, 771-789.<771::AID-FLD672>3.0.CO;2-7

Nairn, R.B., Q. Lu and B.S. Drucker, 2006. Evolution of Dredged Pits Offshore Louisiana And Buffers Around Seabed Infrastructure, Int. Conf. Of Coastal Engineering, Paper 404

Nairn, R.B., Q. Lu, and Langendyk, S.K., 2005. A study to address the issue of seafloor stability and the Impact on Oil and Gas infrastructure in the Gulf of Mexico. U.S. Dept. of the Interior, MMS, Gulf of Mexico OCS Region, New Orleans, L.A. OCS Study MMS 2005-043. 179 pp. + appendices.

Ribberink, J.S., Roos, P.C. and Hulscher, J.H.M., 2005. Morphodynamics of Trenches and Pits Under the Influence of Currents and Waves – Simple Engineering Formulas. Proc. of Coastal Dynamics '05. ASCE.

Svasek, J.N., 1964. Behaviour of trial dredge trench in the sea bed of the North Sea near Scheveningen (in Dutch). Report Deltadienst, the Hague, The Netherlands.

Van Rijn, L.C., 1986. Sedimentation of Dredged Channels by Currents and Waves. J. Waterway, Port, Coastal and Ocean Engineering, Vol. 112, No. 5, p. 541-559.

Van Rijn, L.C., Soulsby, R.L., Hoekstra, P. and Davies, A.G., (editors). 2005. SANDPIT, Sand Transport and Morphology of Offshore Sand Mining Pits. Process knowledge and guidelines for coastal management. End Document, May 2005. Part 1. EC Framework V Project No. EVK3-2001-00056. Aqua Publications, The Netherlands.