On May 12 2022 the Victorian ANCOLD YP members attended a site visit at Cardinia Reservoir in Melbourne’s South East. Cardinia Reservoir is Melbourne’s second largest reservoir after Thomson Dam and holds approximately 287 GL. It is used to supply water to Melbourne’s southern and south-eastern suburbs and store water from the Melbourne desalination plant. Cardinia dam is a 90 m high earth and rockfill dam.
Melbourne Water are currently in the design and planning phase of a safety upgrade for the dam, scheduled for construction in 2024. As part of the planning, geotechnical investigations are being undertaken which involve several ‘mega’ test pits. The ‘mega’ test pits include a 5 m bench excavated from the crest and an additional trench excavated from the bench. The test pits are to identify the type, depth and extent of the existing filters. The information gained will inform the design of the filter raising for the main dam and saddle dams.
With the hiatus of physical events due to COVID in Victoria, the day provided a fantastic opportunity for young professionals to meet their colleagues and expand their networks, with over 45 ANCOLD YPs from all over Victoria in attendance.
As part of the site visit, attendees were able to view two open test pits on the crest of the main dam and listen to presentations by Melbourne Water and AECOM. The presentations included an overview on why the safety upgrade is happening and how the project team plan on executing the works, as well as the key project and construction risks. During the site visit, YPs observed engineers intercepting the filters, taking samples and conducting in-situ testing. The in-situ testing on the filters included a field density test using the sand replacement method and a falling head permeability test to address uncertainties in key design parameters. Ultimately, the information from the investigations will be used in the design of the upgrade and to update the risk assessment.
Thanks to Stephen Chia and James Toose (AECOM) for providing their time and answering all our questions. Likewise, to Mark Side and Mark Arnold (Melbourne Water) for facilitating and providing background to the study. It is sure to be an interesting dam upgrade project and hopefully provide further opportunities for site visits and networking for Victoria’s YPs.
ANCOLD is an incorporated voluntary association of organisations and individual professionals with an interest in dams in Australia.
