Abstract
A robust and practical methodology for predicting future shoreline behaviour along sandy coastlines would be valuable to a broad range of coastal engineering applications. Present approaches for predicting shoreline evolution range from simple linear trend models, which cannot predict observed complex behaviour, to coupled hydrodynamic / sediment transport models, with seasonal to multi-year forecasting generally beyond present model capabilities. In this work a simple empirical shoreline variability model, ShoreFor (Shoreline Forecast), is investigated using a multi-decadal dataset to assess model performance at daily to decadal timescales. Model performance is assessed at five alongshore locations within an embayed study site that experience varying exposure to the offshore wave climate due to prominent adjacent headlands and display alongshore variable behaviour. To determine model sensitivity to input wave conditions, both the measured offshore and transformed (modelled) nearshore wave data are used and results compared. Strengths and limitations of the ShoreFor model are identified and discussed, along with ongoing model development and planned application of this modelling technique for shoreline forecasting using future water level and wave climate scenarios.References
Cowell, P.J, M.J.F. Stive, P.S. Roy, G.M. Kaminsky, M.C. Buijsman, B.G. Thom and L.D. Wright, 2001. Shoreface sand supply to beaches, in Proceedings of the 27th International Conference on Coastal Engineering, ASCE, New York, USA, 2495-2508.
Davidson, M.A., R.P. Lewis and I.L. Turner, 2010. Forecasting seasonal to multi-year shoreline change, Coastal Engineering, 57, 620-629.http://dx.doi.org/10.1016/j.coastaleng.2010.02.001
Davidson, M.A., K.D. Splinter and I.L. Turner (submitted). A simple equilibrium model for predicting shoreline change, submitted to Coastal Engineering.
Dean, R.G., 1973. Heuristic models of sand transport in the surfzone, Proceedings of the 1st Australian Conference on Coastal Engineering, 209-214.
Gourlay, M.R., 1968. Beach and dune erosion tests, Delft Hydraulics Laboratory Report m935/m936, Delft, The Netherlands.
Harley, M.D., I.L. Turner, A.D. Short and R. Ranasinghe, 2011a. Assessment and integration of conventional, RTK-GPS and image-derived beach survey methods for daily to decadal coastal monitoring, Coastal Engineering, 58, 194-205.http://dx.doi.org/10.1016/j.coastaleng.2010.09.006
Harley, M.D., I.L. Turner, A.D. Short and R. Ranasinghe, 2011b. A re-evaluation of coastal embayment rotation: the dominance of cross-shore versus alongshore sediment transport processes in SE Australia, Journal of Geophysical Research, 116, F04033, doi:10.1029/2011JF001989.http://dx.doi.org/10.1029/2011JF001989
Miller, J.K. and R.G. Dean, 2004. A simple new shoreline change model, Coastal Engineering, 51, 531-556.http://dx.doi.org/10.1016/j.coastaleng.2004.05.006
Mole, M.A., M.A. Davidson, I.L. Turner and I.D. Goodwin, 2011. Modelling seasonal to multi-year shoreline change at a sandy embayment on the Australian east coast, in Proceedings of Coasts and Ports 2011, Engineers Australia, Perth.
Short, A.D., 1985. Rip current type, spacing and persistence, Narrabeen Beach, Australia, Marine Geology, 65, 47-71.http://dx.doi.org/10.1016/0025-3227(85)90046-5
Sutherland, J., A.H. Peet and R.L. Soulsby, 2004. Evaluating the performance of morphological models, Coastal Engineering, 51, 917-939.http://dx.doi.org/10.1016/j.coastaleng.2004.07.015"
Wright, L.D., A.D. Short and M.O. Green, 1985. Short-term changes in the morphodynamic states of beaches and surf zones; an empirical predictive model, Marine Geology, 62, 339-364.http://dx.doi.org/10.1016/0025-3227(85)90123-9
Yates, M.L., R.T. Guza and W.C. O'Reilly, 2009. Equilibrium shoreline response: observations and modeling, Journal of Geophysical Research, 114, C09014, 16pp.