THE EFFECT OF THE LONGSHORE DIMENSION ON DUNE EROSION

Jaap van Thiel de Vries, Ap van Dongeren, Robert McCall, Ad Reniers

Abstract


The effect of the longshore dimension on dune erosion is examined numerically with a 2DH process-based model XBeach. Exploratory simulations are presented to examine longshore effects due to directionally spread waves, longshore variation in topography and longshore variation in bathymetry. The simulations reveal that alongshore sediment exchange during a storm surge affects the cross-shore development of the foreshore and can locally increase or decrease storm impact on dunes substantially. This finding illustrates that dune erosion on natural coasts (which are never cylindrical or subject to longcrested waves) is an inherent 2D process for which 1D cross-shore models do not suffice without further assumptions.

Keywords


dune erosion; surfbeat; longshore sediment transport

References


Andrews, D.G., McIntyre, M.E., 1978. An exact theory of nonlinear waves on a Lagrangian-mean flow. Journal of Fluid Mechanics 89 (4), 609–646.http://dx.doi.org/10.1017/S0022112078002773

Deigaard, R., 1993. A note on the three dimensional shear stress distribution in a surf zone. Coastal Engineering, 20(1-2): 157-171.http://dx.doi.org/10.1016/0378-3839(93)90059-H

Feddersen, F., Guza, R.T., Elgar, S., Herbers, T.H.C., 2000. Velocity moments in alongshore bottom stress parameterizations. Journal of Geophysical Research 105 (C4), 8673–8686. http://dx.doi.org/10.1029/2000JC900022

Galapatti, R., Vreugdenhil, C.B., 1985. A depth-integrated model for suspended sediment transport. Journal of Hydraulic Research 23 (4), 359–377.http://dx.doi.org/10.1080/00221688509499345

Goda, Y., 1985. Random Seas and Design of Maritime Structures. University of Tokyo Press, Tokyo.

Herbers, T. H. C., S. Elgar, and R. T. Guza (1994), Infragravity-frequency (0.005–0.05 Hz) motions on the shelf: I. Forced waves, J. Phys. Oceanogr, 24, 917– 927.http://dx.doi.org/10.1175/1520-0485(1994)024<0917:IFHMOT>2.0.CO;2

Holthuijsen, L.H., Booij, N. and Herbers, T.H.C., 1989. A prediction model for sta-tionary short crested waves in shallow water with ambient currents. Coastal Engineering, 13(1): 23-54. http://dx.doi.org/10.1016/0378-3839(89)90031-8

Komar, P.D. and Miller, M.C., 1975. On the comparison between the threshold of sediment motion under waves and unidirectional currents with a discussion of the pratical evaluation of the threshold. Journal of Sedimentary Petrology, 45: 362-367.

Larson, M., Kraus, N.C. and Byrnes, M.R., 1989. SBeach: Numerical model for simu-lating storminduced beach change. Report 1: Empirical foundation and model development, U.S. Army Engineer Waterways Experiment Station, Coastal Engineering Research Center, Vicksburg, MS.

McCall, R.T., J.S.M. Van Thiel de Vries, N.G. Plant, A.R. Van Dongeren, J.A. Roelvink, D.M. Thompson, A.J.H.M. Reniers (2009). Two-dimensional time dependent hurricane overwash and erosion modelling at Santa Rosa Island. Coastal Engineering, Vol. 57, 7, pp. 668-683, DOI: 10.1016/j.coastaleng.2010.02.006. http://dx.doi.org/10.1016/j.coastaleng.2010.02.006

Reniers, A.J.H.M. and Battjes, J.A., 1997. A laboratory study of longshore currents over barred and nonbarred beaches. Coastal Engineering, 30(1-2): 1-21.http://dx.doi.org/10.1016/S0378-3839(96)00033-6

Reniers, A.J.H.M., Van Dongeren, A.R., Battjes, J.A. and Thornton, E.B., 2002. Linear modelling of infragravity waves during Delilah. Journal of Geophysical Research, 107(C10): doi:10.1029/2001JC001083.http://dx.doi.org/10.1029/2001JC001083

Reniers, A.J.H.M., Roelvink, J.A. and Thornton, E., 2004. Morphodynamic modeling of an embayed beach under wave group forcing. Journal of Geophysical Re-search, 109(C01030): doi: 10.1029/2002JC001586. http://dx.doi.org/10.1029/2002JC001586

Roelvink, J.A., 1993. Surf beat and its effect on cross-shore profiles. PhD Thesis, Delft University of Technology, Delft, The Netherlands.

Roelvink. J.A., A.J.H.M. Reniers, A.R. Van Dongeren, J.S.M. Van Thiel de Vries, R. McCall, J. Lescinski, in press, Modeling strom impacts on beaches, dunes and barrier islands. Coastal Engineering, doi:10.1016/j.coastaleng. 2009.08.006

Steetzel, H.J., 1993. Cross-shore transport during storm surges. PhD Thesis, Delft University of Technology, Delft, The Netherlands.

Svendsen, I.A., 1984. Wave heights and set-up in a surf zone. Coastal Engineering, 8(4): 303-329.http://dx.doi.org/10.1016/0378-3839(84)90028-0

Van Gent, M.R.A., Van Thiel de Vries, J.S.M., Coeveld, E.M., De Vroeg, J.H. and Van de Graaff, J., 2008. Large-scale dune erosion tests to study the influence of wave periods. Coastal Engineering, 55(12): 1041-1051.http://dx.doi.org/10.1016/j.coastaleng.2008.04.003

Van Rijn, L.C., 2007. Unified view of sediment transport by currents and waves, part I, II, III and IV. Journal of Hydraulic Engineering, 133(6,7): 649-689 (part I & II), 761-793 (part III & IV).

Van Thiel de Vries, J.S.M., Van de Graaff, J., Raubenheimer, B., Reniers, A.J.H.M. and Stive, M.J.F., 2006. Modeling inner surf hydrodynamics during storm surges, 30th International Conference on Coastal Engineering, San Diego, USA, pp. 896-908.

Van Thiel de Vries, J.S.M., 2009, Dune erosion during storm surges, PhD Thesis, Delft University of Technology, Delft, The Netherlands, 202 pp.

Vellinga, P., 1986. Beach and dune erosion during storm surges. PhD Thesis, Delft University of Technology, Delft, The Netherlands, 169 pp.


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