Increasing needs for new urban water infrastructure are very difficult to meet within existing environmental constraints. New ways must be found to deliver these services with lower water demand, greenhouse gas emissions, and discharge of nutrients. Alternative means of water servicing are being considered for long-term ecological sustainability. An environmental and economic assessment framework combined with various analysis tools like water balance, life-cycle costing, and life-cycle assessment (LCA) is presented in this paper to evaluate a range of alternative water servicing scenarios. LCA has the potential to evaluate development and associated service provision impacts on the environment in the long term, locally and globally. Application of this framework and analysis approaches was demonstrated on a 3062 hectare greenfield development for 86,000 residents near Melbourne.

Rainwater collected from residential roofs and greywater generated from domestic uses except toilets are viewed as possible substitutes for high grade water sources which supply nonpotable indoor uses and irrigation in Australia. This paper searches for alternatives by adopting roofwater and greywater in residential envelope as per Australian water standards. A water balance model Aquacycle was applied to determine storage capacities and to evaluate the percentage reduction in water supplying, stormwater run-off and wastewater disposal, as well as volume of rainwater use and greywater reuse. This study provides the results of greywater recycling, which contributes to the greater saving of mains water supply than rainwater use, and which reduces more than half of the wastewater to receiving waters in the rural township of Cranbrook, Western Australia. The results of this study provide greywater usage (maximum reduction 32.5%) more significantly reduces scheme water supply than rainwater harvesting (maximum reduction 25.1%). Use of greywater on individual residential lots has the dramatic effect for drainage system by reduction approximately 54.1% or 88.1 m 3 /lot/year. The results of rainwater use analysis show explicitly that rainwater tanks are much more effective in intercepting Y. Zhang et al. roof runoff, with the maximum stormwater reduction 48.1% or 68.3 m 3 /lot/year. This research endeavours to offer a typical paradigm for an integrated water system in the rural residential sectors.

This study describes the use of rainwater and greywater (originated from bathroom only) for provision of non-contact indoor and outdoor use in high-rise buildings. A brownfield development site in Box Hill suburb of Melbourne was selected as case study site for this investigation. The performance of alternative servicing options was compared with conventional water supply, stormwater and wastewater servicing. A water balance model UVQ (Urban Volume and Quality) was applied to determine storage capacities and to evaluate the percentage reduction in water supplying, stormwater run-off and wastewater disposal, as well as volumes of rainwater use and greywater reuse. In this study, the impact of variation in collection area (600 m(2) and 900 m(2)) and appliance discharge volumes was examined. A number of demand management options were also investigated. The results of this study indicate greywater reuse is more suited than rainwater use for this development because of the steady, constant supply of greywater compared to the highly fluctuating, storm-event supply of rainwater and the high population density creating comparatively large volumes of greywater.

There is an expectation that many cities in Australia may experience higher temperatures and reduced rainfall in the future. Hence, to support water policy analysis there is a need for predicting water demand and how it changes in response to climate change. This paper describes a methodology to develop a model that explains month-to-month variability in water demand due to climate and weather, on the basis of using statistical methods. To achieve this, we use time series data of historical water use volumes and climate data from relevant weather stations. Applying this model together with hypothetical climate change scenarios, but without community adaptation scenarios, the results indicate that water demand will change moderately and, as may be expected, it is most sensitive to evaporation and temperature, followed by rainfall. With such scenarios, demand is shown to increase by as much as 10-20%, but more realistic climate sequences are required to provide reliable estimates. Given availability of data, this statistical method can be used to support policy analyses in other cities.

No abstract