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Dynamics of tidally-driven circulation in a topographically-complex macrotidal coastal system: the Kimberley, Western Australia.
The main aim of this project is to quantify the dynamics of tidally-driven flows in topographically-complex coastal systems. A series of field experiments coupled with numerical modelling will resolve, for the first time, the local circulation and flow structure in the macrotidal Camden Sound / Montgomery Reef and King Sound regions of the Kimberley coast in Western Australia. The project will address the following questions:
1) What are the mechanisms driving the circulation in the Camden Sound/ Montgomery Reef and King Sound regions?
2) How does complex topography, such as islands, headlands and cluster of islands, affect the circulation and mixing in shallow coastal regions? What is the influence of island clusters on horizontal dispersion?
3) What is the influence of the vertical and horizontal density stratification on both the regional circulation, and the topographically-induced secondary circulation?
In shallow coastal waters, the interactions of external currents with sub-surface topographic features such as reefs, islands and headlands generate complex three-dimensional secondary flows. The secondary circulations provide a direct transport mechanism for carrying materials across the streamlines of the tidal flow and hence significantly influence the distribution of biological material and sediment as well as dissolved chemicals such as nutrients. Through field experiments, the proposed research will extend the current understanding of: the complex wake dynamics downstream of obstacles in oscillating flows, the mechanisms that induce upwelling, and the strength of the induced circulations under different flow conditions. All of these are important for investigating the spatial variability in local flushing rates, retention of waterborne material and patchiness in concentrations of waterborne material. This has important implications for the Kimberley coastline, which is characterised by island archipelagos, through the management of its fisheries and eco-tourism activities and the development of petroleum reserves. It is important to note that although the field work will be carried out in the Kimberley region, the findings of this research will be applicable to a multitude of other aquatic environments.