Dr Graziela Miot Da Silva1, Dr Patrick A Hesp1
1Flinders University, Bedford Park, Australa
The degree, or extent and volume of coastal dunefield development has been frequently attributed to sediment supply and exposure to onshore/alongshore winds above the threshold to initiate sediment transport. Short and Hesp (1984) and Short (1988) argue that in South Australia, where terrigenous sediment supply is very limited, waves are a dominant control in Holocene dunefield development by transporting sediments from the shelf to a degree proportional to their energy. This study is a contribution to this discussion by testing the wind and wave control in dunefield development in a variety of environmental settings across South Australia. Wind data (speed and direction) were obtained from the Bureau of Meteorology for 23 stations along the open and Gulf coastlines of SA. Reanalysis products were also used to fill in spatial gaps in wind measurements. Dunefield dimensions, embayment indentation and exposure to waves were analyzed via ArcMap 10.3.1 using 1 meter resolution Digital Globe imagery. Nearshore bathymetry data compiled by Geoscience Australia was utilised to calculate nearshore slopes from the shoreline to 20 meters water depth. Results show that the biggest dunefields do not correlate with the strongest winds, similarly, areas that experience high aeolian drift potential don’t display large dunefields. In South Australia, the nearshore slope, exposure to waves and winds as well as the average indentation of embayments interplay to produce duenfields of varied sizes, where the largest dunefields occur in coastal areas fully exposed to waves and winds, adjacent to steep nearshore slopes and with open embayments.
Bio to come