AbstractThe study into sand wave dynamics in South Channel commenced after large dune forms were observed in monitoring campaigns following the channel deepening project of the Port of Melbourne. The project involved deepening of the harbor berths and channels, but more importantly, it involved the deepening of South Channel in Port Phillip Bay. South Channel, the main shipping channel, crosses the bay over â‰ˆ20km. The growth of bedforms at various locations in South Channel now threatens to impede marine traffic. The dimensions and migration rate of the bedforms in the channel are remarkable, especially in the harsh flow conditions in the narrow channel. Therefore, the bedforms in South Channel cannot be given an obvious classification. In this paper it is shown that the bedforms in South Channel can be classified as a tidal sand wave type with a method that requires only insight in water depth, tidal flow velocity and grain size. Tidal sand waves are large-scale bedforms generated by recirculating flow cells that drive sediment to the top of a crest and are commonly observed on shallow coastal seas such as the North Sea. The bedform concern in the channel illustrates the necessity of an evaluation of the present, and alternative, channel maintenance strategies. A numerical model in Delft3D software is applied, along with a probabilistic calculation that combines insights from the simulations and survey data, to assess different maintenance strategies.
Borsje, B. W., Hulscher, S. J. M. H., Herman, P. M., & De Vries, M. B. (2009). On the parameterization of biological influences on offshore sand wave dynamics. Ocean dynamics, 659-670.
Borsje, B. W., Roos, P. C., Kranenburg, W. M., & Hulscher, S. J. M. H. (2013). Modeling tidal sand wave formation in a numerical shallow water model: The role of turbulence formulation. Continental shelf research, 17--27.
Borsje, B. W., Kranenburg, W., Roos, P., Matthieu, J., & Hulscher, S. J. M. H. (2014). The role of suspended load transport in the occurrence of tidal sand waves. Journal of Geophysical Research: Earth Surface, 119, 701--716.
Cardno. (2011). Sediment Transport Modelling - Great Sands, Port Phillip. Melbourne.
Hulscher, S. J. M. H.(1996). Tidal-induced large-scale regular bed form patterns in a three-dimensional shallow water model. Journal of Geophysical Research: Oceans, 20727-20744.
PoMC. (2014). Sand Wave Assessment - South Channel Accretion Study.
van Gerwen, W., Borsje, B. W., Damveld, J. H., & Hulscher, S. J. M. H.(2018). Modelling the effect of suspended load transport and tidal asymmetry on the equilibrium tidal sand wave height. Coastal Engineering, 136, 56--64.
Van Santen, R., De Swart, H., & Van Dijk, T. (2011). Sensitivity of tidal sand wavelength to environmental parameters: A combined data analysis and modelling approach. Continental Shelf Research, 966--978.