Year

2014

Degree Name

Bachelor of Environmental Science (Honours)

ANZSRC / FoR Code

05 ENVIRONMENTAL SCIENCES, 050205 Environmental Management

Department

School of Earth & Environmental Sciences

Advisor(s)

Colin Woodroffe

Abstract

Management of coastal dunes is becoming a major focus in modern coastal management. The dunes along the Illawarra coastline provide the first line of defence against wave erosion during storms or act as a sand reservoir for long term recession in response to sea-level rise. This study of Woonona Beach and City Beach in the Wollongong LGA examined changes of long term dune morphological and the implication for future of dune management. Long term changes in morphology and vegetation on local dunes as well as the changes in beach volume over time were analysed. Detailed analysis of photogrammetric and LiDAR data using Beach Profile Analysis Toolbox were performed to determine the changes in dune volume. Beach volume analysis was undertaken to examine how beach and dune profiles altered and to determine changes in sand volume variability and trends of erosion and accretion. The variable position of a delineated 2m contour line across both beach systems was analysed using Digital Shoreline Analysis System. The examination of changes in long-term vegetation trends was done through the analysis of aerial photographs. Resulting dune volumes at City Beach displayed evident decreases in dune volume as a result of the 1974 storm event followed by an extensive period of accretion. Woonona Beach displayed decreases in dune volume between the period 2007-2013, which was also displayed at City Beach. Movement of the 2m contour suggests southerly beach rotation at City Beach and northerly beach rotation at Woonona Beach. Extensive seaward movement of the vegetation line was observed with no evidence of landward movement. A comparison of dune volume and vegetation line found that there was no association between vegetation line movement and periods of erosion and accretion. The ability of BPAT to produce comparable dune http://ro.uow.edu.au/about.htmlvolumes and profiles with ease offers a reliable approach to dune and coastal management. The application of DSAS provided a useful method for examining shoreline change for the 2m contour line proxy shoreline position. This study provides knowledge of long-term dune and vegetation trends for the future management of this coastal zone.

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