Meeting Melbourne's future demand for water using aquifer storage and recovery

Melbourne is one of the fastest growing cities in Australia. City West Water (CWW) has developed an Integrated Water Cycle Management (IWCM) Strategy which includes the development of aquifer storage and recovery (ASR) schemes to store recycled water and storm water to assist with meeting future growth, where these schemes can be demonstrated to be viable and cost effective. The investigation and delivery of ASR projects by CWW is being undertaken in accordance with Australian guidelines, which set out a staged process for developing a scheme involving the use of recycled water. Detailed investigations into the Tertiary sand aquifer, including drilling, test pumping, injection testing, and groundwater and hydrochemical modelling, were used to inform the assessment process. These investigations have confirmed the viability of ASR at the lead site (West Werribee) following a risk-based multi-stage approach with increasing levels of assessment and financial commitment. An ASR scheme has now been constructed at West Werribee with injection trials proposed at a second site. This paper describes the staged investigation process, the key outcomes to date of CWW's investigations, the opportunities that ASR could enable, and the challenges of implementing ASR at CWW.