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TOWARDS A THREE-DIMENSIONAL HYDRODYNAMIC NUMERICAL MODEL OF SEDIMENT DYNAMICS IN MORETON BAY (E)

Moreton Bay is a shallow lagoon on the East coast of Australia with offshore barrier islands separating it from the Coral Sea. Tidal currents and wind-driven resuspension are the primary drivers of active sediment transport zones in these environments. The ocean passages formed by these islands facilitate high tidal energy. Strong south-easterly trade winds are experienced as well as high wind events. Marine sands were the dominant sediment type in the bay prior to European settlement. However, recent large scale catchment degradation coupled with flood events have deposited large quantities of terrestrial mud. The introduction of mud into this highly energetic system has important ecosystem health implications as turbidity events are more likely and to persist for longer durations. Whilst sediment transport processes are conceptually understood, numerical modelling techniques can be employed to better quantify sediment transport rates over time in a complex environmental system. A coupled numerical model of Moreton Bay was developed in Delft3D to better understand the sediment transport rates present. Calibration and validation of the hydrodynamic model was undertaken using field data from current meters and drogues. Sediment transport rates were validated using sedimentation tubes and long term seabed turbidity monitoring. Model results show good agreement with field data achieving R^2 and Nash-Sutcliffe efficiencies in excess of 0.95 for water levels and 0.85 for flow vectors across all layers of depth, with RMSE less than 5cm for water levels and 5cm/s for flow vectors. This offers great insights for the investigation of sediment transport in this coastal embayment.

Authors

Hutley, N. R., The University of Queensland, Australia, nicholas.hutley@uq.net.au

Lockington, J. R., The University of Queensland, Australia, james.lockington@uq.net.au

Grinham, A. R., The University of Queensland, Australia, a.grinham@uq.edu.au

Cossu, R., The University of Queensland, Australia, r.cossu@uq.edu.au

Gibbes, B. R., The University of Queensland, Australia, b.gibbes@uq.edu.au

Details

Poster presentation

Session #:041
Date: 02/28/2017
Time: 15:30 - 16:30
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: 360