Addressing the water-energy-climate nexus conundrum: A systems approach

Session H5: Systems Modeling and Climate Change: A Systematic Methodology for Disentangling Elements of Vulnerability, Adaptation and Adaptive Capacity

Australia has the highest per capita surface water storage capacity of any country in the world. However, this storage capacity is at the mercy of Australia's rainfall, which is the most variable of any continental region. Recent drought shaved more than 1% off the nation's economy and saw unprecedented widespread water scarcity. In South-East Queensland (SEQ), six consecutive annual drops in storage level forced the introduction of water restrictions, limiting over 2 million citizens to less than 30% of pre-drought per capita usage. Moving forward, forecasts of high population growth and climate change will simultaneously increase water demand and significantly reduce reservoir inflows. To respond to these challenges, water authorities are increasingly considering rain­ independent supply alternatives, such as large scale recycling and desalination, for both base load supply and rapid drought response. This water-energy-climate nexus is complex and requires a planning process that accounts for interdependencies, feedbacks and non-linear relationships. A system dynamics approach offers such a suitable platform, and has been utilised by this project to develop a model for evaluating the SEQ bulk water supply system water balance over a 100 year life cycle. The model provides a determination of the best long-term mix of rain-dependent and rain­ independent supply sources, under a growing population and falling annual rainfall, to ensure that a secure water supply is always provided. The model incorporates the GHG implications of such a climate resilient bulk supply source portfolio and provides analysis of some best practice design options to mitigate potential high GHG levels