Evaluation of three full-scale stormwater treatment systems with respect to water yield, pathogen removal efficacy and human health risk from faecal pathogens.

In this study, three full-scale, operational stormwater harvesting systems located in Melbourne, Australia were evaluated with respect to water yields; pathogen removal performance by analysis of native surrogate data (Escherichiacoli, somatic coliphages and Clostridium perfringens); and potential human health risk associated with exposures to faecal pathogens using Quantitative Microbial Risk Assessment (QMRA). The water yield assessment confirmed variation between design and measured yields. Faecal contamination of urban stormwater was site specific and variable. Different treatment removal performance was observed between each of the microbial surrogates and varied between event and baseline conditions, with negligible removal of viruses during event conditions. Open storages that provide a habitat for waterfowl may lead to elevated risk due to the potential for zoonotic transmission. Nevertheless, in the Australian urban setting studied, the potential for human faecal contamination of the separated stormwater system was a critical driver of risk. If the integrity of the sewerage system can be ensured, then predicted health risks are dramatically reduced.

Reuse of urban runoff in Australia: a review of recent advances and remaining challenges.

The degradation of aquatic ecosystems due to hydrologic and water quality impacts of urbanization, combined with increasing water scarcity, has generated increasing interest in the harvesting of urban storm water. This paper reviews the rationale for integrated storm water treatment and harvesting and synthesizes recent advances and trends and knowledge gaps that limit its application. Storm water harvesting is shown to be a viable alternative water supply and to provide a potential solution to the increases in runoff frequency and peak flows that occur as a result of catchment urbanization. In general, treatment technologies for storm water harvesting have been adapted from existing "water-sensitive urban design" approaches, with limited use of traditional water supply and wastewater technologies. Risk management is often lacking, in part due to a lack of relevant guidance. Reported performance shows variable levels of potable water savings, with cases of up to 100% substitution recorded. Costs of storm water harvesting systems are shown to be inversely related to their scale. The limited cost data show the importance of context, with the harvested water costing more or less than alternative supplies, depending on the cost of the alternative. Limited data exist on environmental benefits, such as reductions in pollutant loads and flow peaks. Implementation of storm water harvesting systems is impeded by inadequate data on risk, lifecycle costs, externalities, and water-energy tradeoffs. Furthermore, retrofit of storm water harvesting into existing urban areas is proving to be a challenge, creating an urgent need for specific technologies for use in retrofit situations.

Applying integrated urban water management concepts: a review of Australian experience.

This article explores recent Australian experiences in the application of the concept of integrated urban water management (IUWM) to land development sites through the review of 15 case studies. It discusses IUWM's emergence and comments on the success or otherwise of Australian experience in its application. The understanding of IUWM is maturing within the Australian water industry, an occurrence that has been facilitated by demonstration sites such as those reviewed. Successes include the translation of IUWM concepts into well-functioning operational urban developments, significant reductions in the impact of the urban developments on the total water cycle, and the increasing acceptance of the concept within the water and land development industries. However, there is still room for greater integration of the water supply, stormwater, and wastewater components of the urban water cycle, improved dissemination of knowledge, enhancement of skills in both public and private organisations, and monitoring the performance of systems and technologies.

Development and adoption of a simple nonpoint source pollution model for Port Phillip Bay, Australia.

New computing tools and approaches allow tailored development of software to meet the needs of environmental managers. The processes required for such tailoring fit well with adaptive management concepts where, as knowledge and system understanding develop among managers, the software can be developed or replaced to match. This paper reports on development and adoption of a simple nonpoint source pollution modeling tool, including technical aspects of data support for modeling and social aspects of software design. The software, named FILTER, used a unit load model to generate expected pollutant loads from subcatchments of Port Phillip Bay, Australia. Monitoring data were used for calibration to modify the delivery of generated pollutants to receiving waters. Spatial, tabular, and charting software components were used to provide alternative forms of output visualization. FILTER was developed using a process that resulted in manager-stakeholders taking responsibility for setting of model parameter values and operation of the user interface, thereby encouraging uptake. The inclusive development process, tailoring of the software to manager needs and styles of usage, and matching of model complexity to data and knowledge, resulted in a successful application that has become the current agreed system representation among disparate stakeholder organizations.

Components of the total water balance of an urban catchment.

A daily model was used to quantify the components of the total urban water balance of the Curtin catchment, Canberra, Australia. For this catchment, the mean annual rainfall was found to be three times greater than imported potable water, and the sum of the output from the separate stormwater and wastewater systems exceeded the input of imported potable water by some 50%. Seasonal and annual variations in climate exert a very strong influence over the relative magnitude of the water balance components; this needs to be accounted for when assessing the potential for utilizing stormwater and wastewater within an urban catchment.