Performance Assessment of Brisbane Water Supply

Water supply has received more attention in Australia during recent years than at any previous time in the history of the country. Much of this attention has centred on increased demand on public watersupply systems but also of changes in water supply management itself, driven by COAG and NWI. A significant change in water supply management is the establishment of regulatory programs as a means to trade-off environmental values and economic benefits. The recent completion of the statutory Moreton Water Resource Plan added complexity into Brisbane's current management model due to the limiting nature of the system reliability assessment. Moreton Basin's system is huge and grown in complexity and controversy to require new forms of analysis and new ways of future water management. Major changes in operating rules are being considered to improve the security of the system. Advances in data, tools, and computing made it possible to undertake regional economic and engineering analysis of South East Queensland's water challenges. These data analyses: increase the range and integration of options evaluated, have regard to a non-homogenous system with highly variable run-off and use patterns, improve the speed of analysis, explicitly integrate climatic patterns dominated by sub-tropical influences, incorporate economic and engineering aspects of evaluation, and 'optimise' to suggest promising solutions for more detailed consideration. This paper presents results of a resource assessment model of Brisbane's primary water supply system. The results of this study effort illustrate the value of water resource modelling for providing integrated information needed to manage a complex multipurpose water system. This information includes economic benefits of flexible operations, estimating user willingness to pay for additional water, and economic opportunity costs of environmental flows. Overall, the results suggest improvements to system operation and water allocations with an increase in water availability in the system as high as 60,000 ML/year.