Morphological modelling for the Gold Coast using wave classification

The Gold Coast is exposed to a highly variable wave climate with an estimated average net northward littoral drift of 500,000 m3/yr. Process-based numerical morphological models can be used to estimate sediment transport along the coast by downscaling the wave time series available from global models or wave buoys. However such process-based models are complex and computational time is exhaustive. This paper aims to assess the validity of a wave classification scheme to reduce the computation time required to calculate annual sediment transport along the Gold Coast, Australia. Four wave climate schematisation methods were tested using wave data from 2015 and validated for 2009 using a two-dimensional coupled Delft3D wave, flow and sediment transport model. For each wave classification method, the full wave time series was divided into six, twelve, twenty and thirty parametric wave classes to represent the annual wave climate. Morphological change was multiplied by a factor related to the occurrence of each wave class. The cumulative sediment transport rates for each wave classification were compared against results from a simulation with the full wave time-series used as a benchmark. Six weighted wave conditions using the Energy Flux Method (EFM) was sufficient to represent the full wave time-series and showed minimal relative error with respect to the benchmark case running the full parametric wave time series.Griffith Sciences, Griffith Centre for Coastal ManagementFull Tex