Print Email Facebook Twitter A hybrid model of swash-zone longshore sediment transport on refelctive beaches Title A hybrid model of swash-zone longshore sediment transport on refelctive beaches Author Jiang, A.W. Hughes, M. Cowell, P. Gordon, A. Savioli, J.C. Ranasinghe, R.W.M.R.J.B. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2010-06-30 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 Subject swash zone, wave up-rush, longshore sediment transport, reflective beaches, numerical modeling To reference this document use: http://resolver.tudelft.nl/uuid:fb6762d8-e88a-483f-8f66-e6ed9ff7d7a8 Source Proceedings of 32nd International Conference on Coastal Engineering, ICCE 2010, June/July, Shanghai Part of collection Institutional Repository Document type conference paper Rights (c) 2010 Jiang, A.W., Hughes, M., Cowell, P., Gordon, A., Savioli, J.C., Ranasinghe, R.W.M.R.J.B. Files PDF 278235.pdf 1.26 MB Close viewer /islandora/object/uuid:fb6762d8-e88a-483f-8f66-e6ed9ff7d7a8/datastream/OBJ/view