Headland Sand Bypassing in New South Wales, Australia Classification of Headland Morphology

Abstract Australia’s national sediment compartment framework underpins coastal management in Australia, delineating sediment-sharing systems based on geological and geomorphological transitions. Along the 2000 km coastline of New South Wales (NSW), the numerous headlands often present some form of barrier to northward alongshore sediment transport driven by the modal south-east swell, with sand bypassing an important factor in sediment budget calculation. Despite its noted importance, there has been no systematic investigation of headland morphology or sand bypassing potential in NSW. In this study we use high-resolution topographic-bathymetric data and spatial analysis to classify the morphology of headlands in NSW, which will enable an investigation of bypassing sensitivity to headland morphology in the region. Individual and compound headlands are defined through automated methods, and morphometric parameters are calculated to evaluate sediment connectivity. The results reveal spatial variations in headland distribution and morphology along the coastline, highlighting the influence of both subaerial and subaqueous geomorphology on sediment transport. This analysis will enable the evaluation of sediment compartment boundaries (e.g., open, leaky, closed), providing new insights into headland morphology and sediment bypassing dynamics, to in-form coastal management practices in NSW and elsewhere.