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Sydney Water or formally, Sydney Water Corporation, is a New South Wales Government–owned statutory corporation that provides potable drinking water, wastewater and some stormwater services to Greater Metropolitan Sydney, the Illawarra and the Blue Mountains regions, in the Australian state of New South Wales. Sydney Water has historically held a monopoly over the supply of water within the Sydney region, although legislation has recently been passed to open the market to competition. Wikipedia.

Storey M.V.,Sydney Water | van der Gaag B.,KWR Groningenhaven 7 | Burns B.P.,University of New South Wales
Water Research | Year: 2011

Significant advances have been made in recent years in technologies to monitor drinking water quality for source water protection, treatment operations, and distribution system management, in the event of accidental (or deliberate) contamination. Reports prepared through the Global Water Research Coalition (GWRC) and United States Environment Protection Agency (USEPA) agree that while many emerging technologies show promise, they are still some years from being deployed on a large scale. Further underpinning their viability is a need to interpret data in real time and implement a management strategy in response. This review presents the findings of an international study into the state of the art in this field. These results are based on visits to leading water utilities, research organisations and technology providers throughout Europe, the United States and Singapore involved in the development and deployment of on-line monitoring technology for the detection of contaminants in water. © 2010 Elsevier Ltd.

Johnson F.,Sydney Water | Sharma A.,University of New South Wales
Water Resources Research | Year: 2012

Climate change impact assessments of water resources systems require simulations of precipitation and evaporation that exhibit distributional and persistence attributes similar to the historical record. Specifically, there is a need to ensure general circulation model (GCM) simulations of rainfall for the current climate exhibit low-frequency variability that is consistent with observed data. Inability to represent low-frequency variability in precipitation and flow leads to biased estimates of the security offered by water resources systems in a warmer climate. This paper presents a method to postprocess GCM precipitation simulations by imparting correct distributional and persistence attributes, resulting in sequences that are representative of observed records across a range of time scales. The proposed approach is named nesting bias correction (NBC), the rationale being to correct distributional and persistence bias from fine to progressively longer time scales. In the results presented here, distributional attributes have been represented by order 1 and 2 moments with persistence represented by lag 1 autocorrelation coefficients at monthly and annual time scales. The NBC method was applied to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Mk3.5 and MIROC 3.2 hires rainfall simulations for Australia. It was found that the nesting method worked well to correct means, standard deviations, and lag 1 autocorrelations when the biases in the raw GCM outputs were not too large. While the bias correction improves the representation of distributional and persistence attributes at the time scales considered, there is room for representation of longer-term persistence by extending to time scales longer than a year.

Turak E.,Sydney Water | Turak E.,South Australian Museum | Linke S.,Griffith University
Freshwater Biology | Year: 2011

1. Global freshwater biodiversity is facing rapid decline. Freshwater conservation planning aims to reduce this decline by efficiently prioritising conservation actions. 2. This Special Issue presents nine papers from five continents demonstrating a wide range of approaches to spatial prioritisation for freshwater conservation and two papers that explore directions for research and implementation in conservation planning. 3. Despite an emphasis on running waters and data-rich regions, these papers collectively offer a wide range of perspectives for advancing the science and practice of systematic conservation planning across freshwater realms, including data-poor regions and standing-water ecosystems. © 2010 Blackwell Publishing Ltd.

Johnson F.,University of New South Wales | Johnson F.,Sydney Water | Sharma A.,University of New South Wales
Water Resources Research | Year: 2011

Empirical scaling approaches for constructing rainfall scenarios from general circulation model (GCM) simulations are commonly used in water resources climate change impact assessments. However, these approaches have a number of limitations, not the least of which is that they cannot account for changes in variability or persistence at annual and longer time scales. Bias correction of GCM rainfall projections offers an attractive alternative to scaling methods as it has similar advantages to scaling in that it is computationally simple, can consider multiple GCM outputs, and can be easily applied to different regions or climatic regimes. In addition, it also allows for interannual variability to evolve according to the GCM simulations, which provides additional scenarios for risk assessments. This paper compares two scaling and four bias correction approaches for estimating changes in future rainfall over Australia and for a case study for water supply from the Warragamba catchment, located near Sydney, Australia. A validation of the various rainfall estimation procedures is conducted on the basis of the latter half of the observational rainfall record. It was found that the method leading to the lowest prediction errors varies depending on the rainfall statistic of interest. The flexibility of bias correction approaches in matching rainfall parameters at different frequencies is demonstrated. The results also indicate that for Australia, the scaling approaches lead to smaller estimates of uncertainty associated with changes to interannual variability for the period 2070-2099 compared to the bias correction approaches. These changes are also highlighted using the case study for the Warragamba Dam catchment. Copyright 2011 by the American Geophysical Union.

Joseph A.P.,University of Queensland | Keller J.,University of Queensland | Bustamante H.,Sydney Water | Bond P.L.,University of Queensland
Water Research | Year: 2012

While the involvement of a range of environmental factors in sewer corrosion is known, a comprehensive understanding of the processes involved and the exact role of individual environmental factors in sewer corrosion is still lacking. The corrosion of concrete in sewer systems is reported to be initiated through chemical reactions (involving H2S and CO2) that lower the surface pH to a level then conducive for biological activity. However, the specific influence of environmental variables, such as H2S level, temperature, and relative humidity etc. remains unclear; although, they are expected to control these initial surface reactions of the concrete sewer pipe. We examined changes in the surface chemistry of concrete during the early stages of corrosion by exposing concrete coupons to thirty-six independent conditions in well-controlled laboratory chambers that simulated conditions typically found in various sewer environments across Australia. The conditions employed were combinations of six H2S levels, three gas-phase temperatures and two relative humidity levels. Our results indicate that the role of CO2 on initial surface pH reduction is insignificant when compared to the influence of H2S. Within the first 12 months, a decrease in surface pH by 4.8 units was observed for coupons exposed to 30 °C and 50 ppm H2S, while significantly lower pH reductions of 3.5 and 1.8 units were detected for coupons exposed to 25 °C and 18 °C respectively, and 50 ppm H2S. Elemental sulphur was found to be the major oxidation product of H2S and elevated concentrations were detected at the higher levels of H2S, temperature and relative humidity. More significantly, the data obtained from the controlled chamber experiments correlated with those obtained from the field-exposed coupons. Hence, these findings can be extended to real sewer corrosion processes. © 2012 Elsevier Ltd.

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