Water Journal : Water Journal April 2012
catchment management water APRIL 2012 121 restricted to percentile comparisons over differing time periods (DECCW, 2010). Trends in water quality were variable across the catchment and highly dependent on where in the river system the monitoring site was located. While some improvements in water quality at sites in the Hawkesbury-Nepean River catchment can be demonstrated from these studies, these are improvements from what was previously quite poor water quality in some areas and, for some analytes, water quality still has a long way to go before water quality objectives (e.g. ANZECC Guidelines) are met. Conclusion The routine Water Quality Monitoring Network undertaken by the SCA and SWC contains some of the best long- term series of water data in NSW (and Australia). This is to the credit of the organisations (and their predecessor organisations) and individuals involved in its initial design, implementation and continuance. The data collected up until the present time represents not only a significant historical and ongoing investment, but a very valuable resource in terms of long-term information on water quality and quantity in the Hawkesbury-- Nepean River catchments. These data series represent a significant resource for investigating and interpreting the effects of both past and future NSW Government management decisions. In addition to past Government initiatives (e.g. river regulation and nutrient reduction programs), recent trends in the hydrology and water quality of the Hawkesbury-Nepean River also need to be interpreted in terms of longer-term climate cycles (e.g. El Niño Southern Oscillation and Interdecadal Pacific Oscillation; Power et al., 1999; Kiem & Franks, 2004; Verdon et al., 2004, McNeil and Cox, 2007). Major new Government initiatives (such as the Metropolitan Water Plan) and planned urban expansion will also impact heavily on the Hawkesbury-Nepean River in the near to medium future. In the longer term, there is also the potential for climate change to have important effects in these areas (IPCC AR4, 2007; Chiew et al., 1998; Nicholls and Kariko, 1993). Acknowledgement This analysis could not have taken place without the provision of data (from SWC and SCA) and funding from the SCA. These organisations and many individuals within these organisations are thanked for their assistance. Dr Klaus Koop of OEH was the auditor for the 2010 Audit of the Sydney Drinking Water Catchment and kindly reviewed and improved an earlier draft of this paper. The Author Martin Krogh (email: martin.krogh@environment. nsw.gov.au) is the Project Team Leader (Monitoring) in the Office of Environment and Heritage, Department of Premier and Cabinet. He was responsible for the Hawkesbury-Nepean River Environmental Monitoring Program Final Technical Report and the Project Manager for the 2010 Sydney Drinking Water Catchment Audit. References ANZECC/ARMCANZ, 2000: Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra. Chiew FHS, Piechota TC, Dracup JA & McMahon TA, 1998: El Niño/Southern Oscillation and Australian rainfall, streamflow and drought: Links and potential for forecasting. Journal of Hydrology, 204, pp 138--149. Cleveland WS, 1979: Robust Locally Weighted Regression and Smoothing Scatterplots. Journal of the American Statistical Association, 74, pp 829--836, 1979. DECC, 2009: Hawkesbury-Nepean River Environmental Monitoring Program. Final Technical Report, February 2009. NSW Dept of Environment and Climate Change, Sydney. 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Water Journal May 2012
Water Journal December 2011