A HYBRID MODEL OF SWASH-ZONE LONGSHORE SEDIMENT TRANSPORT ON REFLECTIVE BEACHES
Proceedings of the 32nd International Conference
PDF

Keywords

swash zone
wave up-rush
longshore sediment transport
reflective beaches
numerical modeling

How to Cite

Jiang, A. W., Hughes, M., Cowell, P., Gordon, A., Savioli, J. C., & Ranasinghe, R. (2011). A HYBRID MODEL OF SWASH-ZONE LONGSHORE SEDIMENT TRANSPORT ON REFLECTIVE BEACHES. Coastal Engineering Proceedings, 1(32), sediment.29. https://doi.org/10.9753/icce.v32.sediment.29

Abstract

The hydrodynamics and sediment transport in the swash zone is currently outside the domain of coastal-area models, which is a significant limitation in obtaining littoral sediment-transport estimates, especially on steep reflective beaches where the waves practically break on the beachface. In this study, an existing process-based coastal model (MIKE 21) is combined with a theoretical derivation of swash processes, resulting in an innovative hybrid modelling approach that is capable of estimating longshore sediment transport in the swash zone. The method relies upon estimation of swash hydrodynamics from an extended ballistic swash model with friction included. The terminal bore and other incident wave properties were computed from the output of a spectral-wave model (MIKE 21 SW). The Bagnold-type equation was applied to estimate gross transport volumes and the longshore component was computed for the sand volume displaced during the up-rush. The newly developed hybrid modelling approach was applied to Jimmys beach, a steep reflective beach (D50 = 0.3 mm, gradient=0.1) along the northern shoreline of Port Stephens, Australia. The model results yield the alongshore swash transport pathways and the indicative transport volumes. A point of divergence is identified at the beach erosion area, which is of critical importance in terms of shoreline erosion and management. The preliminary results suggest that swash-zone transport can account for a large percentage of the total littoral drift for such beaches. However, further field or laboratory data are required to test model utility, as well as to tune calibration parameters based on the site-specific conditions.
https://doi.org/10.9753/icce.v32.sediment.29
PDF

References

Bagnold, R. A. (1963) Mechanics of marine sedimentation. In: HillL M.N. (ed.), The Sea-Ideas and Observations. Wiley, New York, pp. 507-528.

Bagnold, R. A. (1966) An Approach to the Sediment Transport Problem from General Physics. United States Geological Survey Professional Paper, 422-I, 37pp.

Bakhtyar, R., Barry, D. A., Li, L., Jeng, D. S. & Yeganeh-Bakhtiary, A. (2009) Modeling sediment transport in the swash zone: A review. Ocean Engineering, 36, 767-783.http://dx.doi.org/10.1016/j.oceaneng.2009.03.003

Baldock, T. & Holmes, P. (1997) Swash Hydrodynamics on a Steep Beach. In: Coastal Dynamics '97. New York, ASCE, 784- 793.

Baldock, T. E., Weir, F. & Hughes, M. G. (2008) Morphodynamic evolution of a coastal lagoon entrance during swash overwash. Geomorphology, 95, 398-411.http://dx.doi.org/10.1016/j.geomorph.2007.07.001

Bodge, K. R. & Dean, R. G. (1987) Short-term impoundment of longshore transport. In: Proceedings of Coastal Sediments '87. . New York, ASCE, 468-483.

Bradshaw, M. P. (1980) Topographic control of run-up variablility. In: Proceedings 17th Coastal Engineering Conference. ASCE.

Butt, T. & Russell, P. (2000) Hydrodynamics and Cross-Shore Sediment Transport in the Swash-Zone of Natural Beaches: A Review. Journal of Coastal Research, 16, 255-268.

Elfrink, B. & Baldock, T. (2002) Hydrodynamics and sediment transport in the swash zone: a review and perspectives. Coastal Engineering, 45, 149-167.http://dx.doi.org/10.1016/S0378-3839(02)00032-7

Freeman, J. C. & Lemehaute, B. (1964) Wave breakers on a beach and surges on a dry bed. Journal of the Hydraulics Division, Proceedings of the American Society of Civil Engineers, 90, 187-216.

Hardisty, J. (1986) A morphodynamic model for beach gradients. Earth Surf, Processes Landforms 11, 3277333.http://dx.doi.org/10.1002/esp.3290110310

Hardisty, J., Collier, J. & Hamilton, D. (1984) A calibration of the Bagnold beach equation. Marine Geology, 61, 95-101. http://dx.doi.org/10.1016/0025-3227(84)90110-5

Ho, D. V., Meyer, R. E. & Shen, M. C. (1963) Long surf. Marine Res, 1963, 21, 219-230.

Holland, K. T. & Puleo, J. A. (2001) Variable swash motions associated with foreshore profile change. J. Geophys. Res., 106, 4613-4623. http://dx.doi.org/10.1029/1999JC000172

Hughes, M., Aagaard, T. & Baldock, T. (2007) Suspended Sediment in the Swash Zone: Heuristic Analysis of Spatial and Temporal Variations in Concentration. Journal of Coastal Research, 23 (6), 1345-1354 http://dx.doi.org/10.2112/05-0531.1

Hughes, M. & Baldock, T. (2004) Eulerian flow velocities in the swash zone: field data and model predictions. Journal of Geophysical Research, 109.

Hughes, M., Masselink, G. & Brander, R. (1997) Flow velocity and sediment transport in the swash zone of a steep beach. Marine Geology, Vol. 138, no. 1-2, pp. 91-103. Apr 1997.http://dx.doi.org/10.1016/S0025-3227(97)00014-5

Hughes, M. G. (1992) Application of a Non-Linear Shallow Water Theory to Swash following Bore Collapse on a Sandy Beach. Journal of Coastal Research, Vol. 8, No. 3, pp. 562-578.

Kamphuis, J. W. (1991) Alongshore sediment transport rate distribution. Proceedings Coastal Sediments '91, ASCE.

Kemp, P. H. (1975) Wave asymmetry in the nearshore zone and breaker area, Wiley, New York (1975), pp. 47-67.

Kirkgöz, M. S. (1981) A theoretical study of plunging breakers and their run-up. Coastal Engineering,5, 353-370. http://dx.doi.org/10.1016/0378-3839(81)90023-5

Larson, M., Kubota, S. & Erikson, L. (2004) Swash-zone sediment transport and foreshore evolution: field experiments and mathematical modeling. Marine Geology, 212, 61-79.http://dx.doi.org/10.1016/j.margeo.2004.08.004

Lord, D. & Kulmar, M. (2000) The 1974 Storms Revisited: 25 Years Experience in Ocean Wave Measurement Along the South-East Australian Coast. IN: BILLY, L. E. (Ed.) Proceedings of the 27th Conference on Coastal Engineering. Sydney, ASCE.

Masselink, G. & Hughes, M. (1998) Field investigation of sediment transport in the swash zone. Continental Shelf Research, 18, 1179-1199.http://dx.doi.org/10.1016/S0278-4343(98)00027-2

Masselink, G. & Puleo, J. A. (2006) Swash-zone morphodynamics. Continental Shelf Research, 26,661-680. http://dx.doi.org/10.1016/j.csr.2006.01.015

Meyer-Peter, E. & Muller, R. (1948) Formulas for bed-load transport. 2nd Congress of the International Association for Hydraulics Structures Research. Stockholm, Sweden.

Nielsen, P. (2002) Shear stress and sediment transport calculations for swash zone modelling. Coastal Engineering, 45, 53-60.http://dx.doi.org/10.1016/S0378-3839(01)00036-9

Puleo, J. A., Beach, R. A., Holman, R. A. & Allen, J. S. (2000) Swash zone sediment suspension and transport and the importance of bore-generated turbulence. J. Geophys. Res., 105, 17021-17044.http://dx.doi.org/10.1029/2000JC900024

Puleo, J. A. & Holland, K. T. (2001) Estimating swash zone friction coefficients on a sandy beach. Coastal Engineering, 43, 25-40. http://dx.doi.org/10.1016/S0378-3839(01)00004-7

PWD (1987) Jimmys Beach Erosion Study. PWD NSW Report No. 85042.

Raubenheimer, B., Elgar, S. & Guza, R. T. (2004) Observations of swash zone velocities: A note on friction coefficients. J. Geophys. Res., C01027, 109.

Raubenheimer, B., Guza, R. T., Elgar, S. & Kobayashi, N. (1995) Swash on a gently sloping beach. J. Geophys. Res., 100, 8751-8760. http://dx.doi.org/10.1029/95JC00232

Shen, M. C. & Meyer, R. E. (1963) Climb of a bore on a beach: Part three run-up. Journal of Fluid Me- chanics, 16, 113-125. http://dx.doi.org/10.1017/S0022112063000628

Short, A. D. & Trenaman, N. L. (1992) Wave Climate of the Sydney Region, an Energetic and Highly Variable Ocean Wave Regime. Australia Journal of Marine and Freshwater Research, 43,26.http://dx.doi.org/10.1071/MF9920765

Smith, E. R., Wang, P., Ebersole, B. A. & Zhang, J. (2009) Dependence of Total Longshore Sediment Transport Rates on Incident Wave Parameters and Breaker Type. Journal of Coastal Research, 25, 675-683.http://dx.doi.org/10.2112/07-0919.1

Sunamura, T. (1984) Quantitative prediction of beach face slopes. Geol. Sot. Am. Bull, 95, 242-245.http://dx.doi.org/10.1130/0016-7606(1984)95<242:QPOBS>2.0.CO;2

Turner, I. L. (1995) Simulating the influence of groundwater seepage on sediment transported by the sweep of the swash zone across macro-tidal beaches. Mar. Geol., 125, 153-174. http://dx.doi.org/10.1016/0025-3227(95)00026-U

Van Wellen, E., Baldock, T., Chadwick, A. & Simmonds, D. (2000) STRAND - a Model for Longshore Sediment Transport in the Swash Zone. Proceedings of the 27th Conference on Coastal Engineering. Sydney, ASCE, 3139-3150.

Wright, L. D. & Short, A. D. (1984) Morphodynamic variability of surf zones and beaches: a synthesis. Mar. Geol., 93-118. http://dx.doi.org/10.1016/0025-3227(84)90008-2

Yeh, H. H., Ghazali, A. & Marton, I. (1989) Experimental study of bore run-up. Journal of Fluid Mechanics Digital Archive, 206, 563-578.

Authors retain copyright and grant the Proceedings right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this Proceedings.