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Quantification of the Physical Impacts of Climate Change on Beach Shoreline Response
Christopher Huxley (2011). Quantification of the Physical Impacts of Climate Change on Beach Shoreline Response MPhil Thesis, School of Engineering, Civil Engineering, The University of Queensland.
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| Author
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Christopher Huxley
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| Thesis Title
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Quantification of the Physical Impacts of Climate Change on Beach Shoreline Response
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| School, Centre or Institute
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School of Engineering, Civil Engineering
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| Institution
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The University of Queensland
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| Publication date
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2011-02
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| Thesis type
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MPhil Thesis
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| Supervisor
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Peter Nielsen
Tom Baldock
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| Total pages
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141
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| Total colour pages
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71
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| Total black and white pages
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70
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| Subjects
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09 Engineering
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| Abstract/Summary
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Assessing the possible impacts of future climate change is a major issue currently requiring attention by governments worldwide. By assessing the likely impacts of climate change for the full range of environmental and regional sectors, governments will be able to prioritise adaptive strategies to manage the climate change impacts in an economically responsible way. This study represents a portion of a NSW state government funded study assessing the possible impacts of climate change to the NSW coastline. As part of this study, a modelling approach capable of assessing the impact of climate change to the existing shoreline has been developed. The developed modelling approach, based on existing coastal engineering theory, has been designed specifically to assess the impact of climate change on shoreline response for an open coast beach. The time stepping model further develops the Miller and Dean (2004) cross-shore model using a geometric representation of the cross-shore profile. The geometric approach has been applied using Bruun Rule style conservation of mass principles. To assess the possible shoreline response to the combined impact of climate change driven sea level rise and variations in wave climate, developed cross-shore and longshore models have been dynamically linked. Combining of the modelling programs has enabled an efficient way to assess the likely impacts of climate change on shoreline response. Specifically, the assessment of the likely impacts of climate change variations predicted by McInnes et al. (2007) on Wooli Wooli Beach has been undertaken using this developed modelling approach. Summarising the findings specific to Wooli Wooli Beach, using the developed assessment approach, accounting for the combined impact of climate change on cross shore and longshore sediment transport processes, the results indicate there is a significant non-uniform alongshore response to the climate change forcing. The results show that greatest shoreline recession is likely to occur along the southern section of Wooli Wooli beach, adjacent to the northern training wall of the Wooli Wooli River. North of this location the shoreline recession results are reduced, with the northern section of Wooli Wooli beach exhibiting the smallest recession. Alongshore, for the three assessed climate change scenarios, at the southern end of Wooli Wooli beach where the predicted erosion is of the greatest magnitude between 73m and 83m of shoreline recession is predicted. Comparing the various scenario results, it is evident that the projected increases in sea level dominate the shoreline response at Wooli Wooli. Projected changes in wave climate are predicted to have an effect of the future shoreline evolution, though the magnitude of change is comparably less than that resulting from sea level rise in isolation. In the broader context of shoreline response to climate change, the Wooli Wooli assessment results highlight some interesting trends. The results indicate that shoreline response to sea level rise is highly non-uniform for littoral drift dominated coastlines. Where the annual net longshore transport pattern dominates, such as at Wooli Wooli Beach, the modelling results indicate beach sections immediately downdrift from major headland/groyne controls are likely to experience the greatest shoreline recession. These results highlighted the need to account for both cross shore and longshore processes during climate change assessments for littoral drift dominated coastlines, typical of northern NSW. Traditional climate change assessments using the Bruun Rule, represent only a cross shore assessment, and do not account for the joint interaction of the shoreline evolution to combined cross shore/longshore processes. Using the developed timestepping model approach outlined in this paper, more detailed shoreline response assessments are now able to be conducted, accounting for these complex sediment transport processes.
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| Keyword
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Climate Change Impact
Sediment Transport
Shoreline Response
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| Additional Notes
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colour = 4,24,25,26,27,28,30,31,33,34,42,44,45,48,49,56,59,60,61,62,66,68,69,73,74,75,76,78,80,81,82,84,85,87,88,89,90,92,93,94,95,96,97,98,99,100,101,103,104,105,107,109,110,111,112,114 ,116,117,118,119,121,123,124,125,126,128,130,131,132,133 A3 landscape = 73, 132
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