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Summary: Yield plays a central role in the processes, practices, management and operation of urban water supply systems. Improved accuracy of the yield estimate is important and can be obtained by improving knowledge of important variables. Yield is typically estimated via computational simulation using the entire sequence of available historic climate data. Sensitivity analysis provides a framework and many techniques that can identify important variables in a computational model. Using the Morris method, this paper investigates the importance of input variables used in the estimation of yield of urban water supply systems. The Barwon urban water supply system in Australia is used as the case study. Using a number of climate scenarios of various lengths, sensitivity analysis showed that the security criteria of the Barwon system was the most important to the yield estimate. The upper restriction rule curve also showed notable importance. Significantly the results showed that the use of a single climate sequence for estimating yield would produce misrepresentative results for another climate scenario. [ABSTRACT FROM AUTHOR]

Summary: Melbourne is facing a severe drought having its 12th consecutive below average rainfall year. Water authorities have been forced to impose rigorous water restrictions including voluntary per capita water use targets after more than 20years of unrestricted water supply. The current severe drought and dwindling water resources have accelerated the use of alternative water sources including domestic rainwater. There is a large variation in average annual rainfall in the Greater Melbourne area ranging from 1050mm in the east to 450mm in the west. Hence, there is a significant difference in the tank size required in the west and the east of Melbourne to meet a similar demand and to provide the same supply reliability. The paper presents a novel methodology and a relationship for optimal sizing of rainwater tanks considering the annual rainfall at the geographic location, the demand for rainwater, the roof area (catchment area) and the desired supply reliability. The characteristic of the developed dimensionless curve reflects these variables and paves the way for developing a web based interactive tool for selecting the optimum rainwater tank size. [Copyright &y& Elsevier]

Summary: The paper conceptualises new environmental derivatives, water options, which can be used as an important leverage to facilitate the growing Australian water market. A model of water option pricing has been developed. This model is based on the theory of stochastic processes with jumps. The developed model is justified by analysis of real price dynamics in water market in northern Victoria, Australia. The price of European call options is modelled as a Brownian motion and compound Poisson process. The numerical simulation for modelled water and option prices is obtained for a set of predefined jumps and hypothetical water price. Potential impacts of the introduction of water options on irrigators and the water market are discussed. [Copyright &y& Elsevier]