Morphological changes following vegetation removal and foredune re-profiling at Woonona Beach, New South Wales, Australia

Abstract

Dunes are important for coastal protection, but their presence can sometimes be seen as conflicting with the recreational use of the coastline. In June 2014, in response to community concern, Wollongong City Council, a local government authority in southeast Australia, took the unconventional step of removing vegetation and re-profiling the foredune in a section of Woonona Beach to improve beach width and sightlines. A series of cross-sections in the re-profiled and adjacent unmodified areas have been surveyed monthly since July 2013, to help determine the impact of the intervention on beach and foredune topography. These show that immediately after re-profiling, considerable additional lower beach width was gained, and there was little accretion on the foredune that had been re-profiled. However, after 8 months, the importance of the re-profiling in maintaining lower beach width is less clear, and an incipient foredune is emerging at the new vegetation line, with about half the volume of sand removed during re-profiling re-deposited in this area. After 21 months, lower beach width gain from re-profiling had disappeared, and the volume of sand deposited on the new incipient foredune is more than the volume removed by the re-profiling. The results are discussed in terms of whether the short-term outcomes achieved by the re-profiling are being compromised, and what on-going management will be required to maintain these over the longer term. This study highlights the challenges facing coastal managers trying to balance conflicting community objectives at beaches backed by vegetated dunes.