Join us for an exclusive behind-the-scenes tour of the Lake Macdonald Dam Improvement Project, one of Southeast Queensland’s most significant water infrastructure upgrades.
Delivered by Seqwater in partnership with John Holland, this major project is enhancing dam safety, improving water security, and increasing resilience to extreme weather events. Scheduled for completion in late 2029, the upgrade will ensure Lake Macdonald Dam meets modern engineering and regulatory standards while continuing to serve the region for generations to come.
During this site visit, participants will gain firsthand insight into the planning, design, environmental management, and construction of this complex infrastructure project. Participants will learn about the challenges and opportunities associated with lake lowering, water quality management, ecological protection, erosion control, and the delivery of major construction works in a live operational watery supply environment.
The tour will showcase innovative engineering and construction solutions, including the construction of a temporary upstream cofferdam, installation of deep secant pile foundations, development of a new concrete spillway system, reconstruction of earth embankments, and implementation of advanced water management controls.
A key feature of the project is the unique split-level spillway design, incorporating both an ogee crest and a labyrinth spillway to improve flood capacity while maintaining the existing dam height. Participants will also gain an understanding of how the project team is managing environmental, construction, operational and community challenges throughout delivery.
Learning Outcomes
By attending this site visit, participants will:
- Understand the engineering and construction techniques used to upgrade an existing dam while maintaining water supply operations and environmental protection.
- Explore the design, construction and delivery challenges associated with the new dam wall and spillway at Lake Macdonald.
- Gain insight into innovative flood management solutions, including the use of labyrinth spillways and secant pile wall construction.
- Learn about the installation, commissioning and operation of the lake siphon system, and how project activities are coordinated with Seqwater operational teams to maintain water supply to the Noosa region.
- Understand the planning and execution of the spillway demolition program, including 15 days of continuous works to safely remove the existing structure.
- Explore the process of lowering Lake Macdonald to 42% of Full Supply Level, including water quality management and ecological considerations.
- Learn about fish salvage and aquatic species relocation programs undertaken prior to lake lowering, including the protection of threatened species such as the Mary River Cod.
- Gain insight into ongoing environmental monitoring programs including, turtle, platypus, fish and habitat surveys.
- Understand how upstream and downstream erosion, scour and vegetation impacts are monitored and managed throughout construction.
- Learn about the project’s ongoing ecological monitoring and reporting activities across the wider lake catchment.
- Learn about water quality management, erosion and sediment control measures, and the environmental safeguards implemented during project delivery.