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Complexity of three NSW coastal dune fields

William Farebrother, Paul Hesse, Ian Goodwin
Macquarie University, Sydney, NSW, Australia

During the 20th and 21st centuries the mapping of coastal dune fields relied upon site visits and analyses of a series of aerial photos and/or satellite imagery. This methodology was often costly (both in time and capital) and due to varying degrees of vegetation cover often biased to sites that had been previously visited or those with limited vegetation cover obscuring the dune surface. Recently, LiDAR datasets have been successfully utilised internationally to map coastal dune systems and estimate how active some of these systems are (Woolard and Colby 2002, Zhou and Xie 2009, Allen, Oertel et al. 2012).

A preliminary analysis (as part of a 9 month Masters of Research study- still ongoing)  of coastal dune morphology utilising LiDAR-based Digital Elevation Models (DEMs) of three dune fields along the NSW coastline. The three are the Seal Rocks, Stockton and Booderee embayments. This has enabled the high resolution mapping of these systems which subsequently highlighted how invaluable LiDAR can be within the geomorphology realm.  The project resulted in the location of a series of previously unmapped dunes and has highlighted that these systems can have a high degree of complexity.

The study utilised a number of GIS-based analyses including flow direction and watershed modelling to map dune crests throughout the dune fields. Fieldtrips will be undertaken at a later date to explore the depth of the inter-dune surfaces which will then aid the creation of a more accurate before surface and the estimation and comparison of dune volumes between the different systems.

Allen, T. R., G. F. Oertel and P. A. Gares (2012). "Mapping coastal morphodynamics with geospatial techniques, Cape Henry, Virginia, USA." Geomorphology 137(1): 138-149.

Woolard, J. W. and J. D. Colby (2002). "Spatial characterization, resolution, and volumetric change of coastal dunes using airborne LIDAR: Cape Hatteras, North Carolina." Geomorphology 48(1–3): 269-287.

Zhou, G. and M. Xie (2009). "Coastal 3-D Morphological Change Analysis Using LiDAR Series Data: A Case Study of Assateague Island National Seashore." Journal of Coastal Research 25(2): 435-447.