Melbourne Water (MW) has a long-term program of assessment and upgrade works at Upper Yarra Dam with the objective of safe management and operation of the reservoir – one of MW’s most critical water supply assets.  AECOM has provided a range of services at Upper Yarra Dam over the last 10 years including:

  • Geotechnical Investigations
  • Design engineering assessments and detailed dam safety risk assessments
  • Comprehensive Inspections in 2012 and 2017, as well as the current 2022 Comprehensive Inspection
  • Spillway investigations including assessing the risk posed by ongoing Alkali Silica Reaction to the stability of the structure, and concept design of remedial works
  • Hydraulic CFD modelling of the spillway
  • Detailed design for the dam safety upgrade of the embankment to install defensive filter protection and a seepage weir at the embankment toe from 2016-18
  • Support to MW during construction including technical advice and quality assurance for the dam safety upgrade works completed between 2019 and 2021
  • Ongoing projects including an engineering assessment of the spillway and options assessment for the reservoir outlet

 Approach

A major part of AECOM’s involvement was focused on the recently completed embankment upgrade project which commenced design in 2017 and construction works in 2019.

This project exemplifies AECOM’s technical capability and collaborative approach to design and construction which helped MW to deliver this important project while maintaining continuous operation of Upper Yarra Reservoir.

AECOM implemented engineering analysis methods that have been described as ‘state of the art’ to develop inputs to the qualitative risk assessment and assess the performance of the existing structure and determine the scope of the upgrade works.

The design was reviewed by an independent peer review panel of experts engaged by MW.  During the tendering phase, AECOM worked with MW to develop comprehensive project risk register to identify and mitigate potential project risks.  This resulted in the incorporation of a geotechnical baseline report into the tender documents which is understood to be a first in the Australian dam construction industry.

Through construction, AECOM brought extensive experience in embankment dam construction to address constructability and safety in design. AECOM worked closely with MW and the Contractor to overcome challenges including the Black Summer bushfires and COVID-19 impacts to deliver a successful project completion.

Outcomes and Value

  • In-depth understanding of the existing dam structure and the ongoing dam safety management of Upper Yarra Reservoir.
  • Robust, defensible dam safety embankment upgrade that satisfies the principles of ALARP (As-Low-As-Reasonably-Practicable).
  • Strong value-for-money offering provided through our involvement in the design, tendering and construction phases of the Dam Safety Upgrade works.

These projects demonstrate how AECOM has worked closely with MW to develop and deliver a range of best-for-project solutions across all relevant disciplines.