Bachelor of Environmental Science (Honours)
School of Earth & Environmental Science
French, Caroline E., Concentrations of Enterococci in Relation to Rainfall in Sutherland Shire Catchments, Bachelor of Environmental Science (Honours), School of Earth & Environmental Science, University of Wollongong, 2012.
The protection of coastal water users from health problems due to pollution is a key responsibility of local and state governments in Australia. There is a continuing interest in finding better indicators and predictors of water pollution. The study of faecal contamination in Sutherland Shire recreational waterways was undertaken to examine the relationship between enterococci densities in coastal waters (as an indication of pollution) and catchment rainfall. Sutherland Shire Council would like to use such a relationship to predict the occurrence of elevated faecal contamination in recreational waters, and thus reduce human exposure to the potential health effects associated with contaminated water. Eight sites were selected for study based on water contamination history and popularity for recreational use. Extensive water quality and rainfall data from local and state government records was synthesised and subjected to multiple regression analyses. The results of the analyses indicated no statistical correlations between rainfall and enterococci concentrations for any site. Indicator bacteria densities were found to be highly variable and a number of temporal, spatial and environmental factors were identified as influencing enterococci levels in waterways. In addition, recent upgrades of sewerage systems in the Sutherland Shire have significantly reduced the frequency of sewage overflows in the area. These findings established that the use of rainfall to predict bacterial concentrations in Sutherland Shire coastal waters was extremely limited. This study demonstrated that systems within Sutherland Shire catchments are too complex to model using any single rainfall variable. More complex models incorporating a number of different variables may improve the capacity to predict enterococci concentrations in recreational waters.