Year

2014

Degree Name

Bachelor of Environmental Science (Honours)

ANZSRC / FoR Code

0502 ENVIRONMENTAL SCIENCE AND MANAGEMENT

Department

School of Earth & Environmental Sciences

Advisor(s)

Colin Woodroffe

Abstract

Intermittently closed and open lakes and lagoons (ICOLLs) are coastal environments that are prominent features of the NSW coastline. On the south coast ICOLLs are often extensively developed environments, resulting in ICOLL processes being of significance not only ecologically but also for the surrounding community. Consequently ICOLLs are the focus of extensive management, including artificial entrance openings. The natural entrance regime of ICOLLs represents a balance between rainfall, stream-flow and wave processes, which are themselves driven by dominant climatological processes including the El Niño Southern Oscillation. Changes in the entrance regime of ICOLLs due to artificial management and increases in the prevalence and severity of rainfall and storm events due to changes in climate are therefore likely to influence ICOLL processes. With a focus on the entrance processes of a number of ICOLLs on the NSW South Coast, this study explores correlation between the El Niño Southern Oscillation (ENSO), and the entrance regime.

The ICOLLs included in this study are located in the Shoalhaven City Council, Eurobodalla Shire Council and Bega Valley Shire Council local government areas. The entrance regime of these ICOLLs comprises both natural and artificial openings over the study period from 1992 – 2013. Long-term in-situ data representing the wave climate, ICOLL water level and catchment rainfall was analysed with respect to the Southern Oscillation Index (SOI) to determine if the entrance condition of the ICOLLs is correlated to the El Niño Southern Oscillation through the application of comparative and statistical methodologies. The results of the analysis show that there is no correlation between the ICOLL entrance condition and the El Niño Southern Oscillation for the study ICOLLs. Although the wave climate and catchment rainfall are correlated to the El Niño Southern Oscillation at some sites, there is no correlation between the wave climate, catchment rainfall and the ICOLL entrance condition. The results indicate that overall the El Niño Southern Oscillation is not a direct influence on the entrance regime of these ICOLLs on the NSW south coast.

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