An exploratory analysis of water quality in the Nepean River, Australia

The Hawkesbury-Nepean River system is an icon of Australia's largest city Sydney with important ecological, social and environmental values. Using 20 years of water quality data, this paper examines how various pollutants are correlated in this river. Prediction equations are developed for Chlorophyll-a, total nitrogen and total phosphorous as a function of easily measurable water quality parameters. These equations show a reasonably high coefficient of determination and a smaller standard error of estimates. The standardized residuals do not show any noticeable trends. These equations thus satisfy the assumptions of the least squares regression very well. These equations can be used to predict Chlorophyll-a, total nitrogen and total phosphorous without going through the expensive and time consuming chemical analysis. Further investigation is being carried out to identify the sources of various pollutants in the Hawkesbury-Nepean River and the attenuation and transport processes of these pollutants. It is expected that the outcomes of this study would assist to understand the heath of the Hawkesbury-Nepean River better and thereby to set up appropriate strategies to preserve and enhance the water quality of this river.