Hydrodynamic processes of fringing reef systems

Soheila Taebi

    Research output: ThesisDoctoral Thesis

    249 Downloads (Pure)


    The circulation driven by wave breaking, tides and winds within a fringing coral reef system (Ningaloo Reef) in Western Australia was investigated using field observations and numerical modelling of a section of reef at Sandy Bay. The observed circulation followed a consistent pattern, with cross-reef flows driven over the reef flat and offshore directed return flows out the reef gaps (channels). A numerical model of the study area was developed using the three-dimensional ocean circulation model (ROMS) coupled to the wave model SWAN, which was able to accurately predict the waves and currents throughout this morphologically complex reef-lagoon system when forced with realistic offshore wave conditions, tides and winds. The relative importance of waves, tide and wind forcing on the circulation and flushing of Sandy Bay was investigated using both the observations and modelling, and revealed the dominant role wave breaking plays in driving the overall reef-lagoon circulation. However, these wave-driven currents were also found to be modulated at tidal frequencies via two mechanisms: one associated with the ebb/flood cycle of the tide and the second associated with tidal modulations of the wave-driven currents. Wind forcing and buoyancy effects were both found to be negligible in driving the circulation and flushing of the system during the field experiment. The importance of these wave driven currents to Ningaloo Reef was quantified over a full seasonal cycle, including during periods when wave and wind conditions significantly differed. The results from monthly model runs forced by historical mean offshore wave and wind condition showed that wave breaking still overwhelmingly dominated the circulation and flushing time of Ningaloo Reef throughout the year, with winds playing an insignificant role.
    Original languageEnglish
    QualificationDoctor of Philosophy
    Awarding Institution
    • The University of Western Australia
    • Pattiaratchi, Charitha, Supervisor
    • Lowe, Ryan, Supervisor
    • Ivey, Gregory, Supervisor
    Award date23 Jul 2012
    Publication statusUnpublished - 2012


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