Flood-tide Delta Morphological Change at the Gippsland Lakes Artificial Entrance,Australia (1889–2009) |
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| Authors: | Peter Wheeler Jim Peterson Lee Gordon-Brown |
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| Institution: | Monash University , Australia |
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| Abstract: | Analysis of historical survey and navigation charts, aerial imagery, and digital hydro-data (representing a time-series of 1889–2009) allows the morphological evolution of a flood-tide delta at the artificial entrance to the Gippsland Lakes (Victoria, Australia) to be visualised and quantified. Analysis shows that flood-tide delta growth has imposed progressively greater demands upon port managers for publicly funded maintenance dredging. This flood-tide delta growth corresponds with a progressive diminution of Gippsland Lakes catchment river discharge volumes, and dampening of flow variability, due to both regional precipitation pattern changes and changes in catchment water resource allocation. Future climate change predictions for the Gippsland Lakes catchment and coastal area suggest both further decreases in catchment river discharge, and changing sediment flux along this sector of the Ninety Mile Beach. Thus, scope for flood-tide delta nourishment will probably increase, as will the demand for mitigation of the inevitable effects upon entrance channel navigability. Information derived from the analysis of time-series bathymetry used for this study offers baseline information in support of stakeholder consensus building regarding options for maintaining navigability. Analysis points to the merit of considering (and testing via morphological modelling) alternative options for navigation channel maintenance than those in present practice. We argue that the circumstances prevailing at the artificial entrance call for consideration of engineered configuration changes practised elsewhere by entrance managers faced with similar issues. |
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| Keywords: | Flood-tide delta ebb-tide delta coastal lagoon digital elevation model |
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