Yan Yean Water Treatment Plant, Pump Station and Pipeline
As part of the Safety Focused Performance Joint Venture (SFPJV), we worked with Melbourne Water to deliver the Yan Yean Works Bundle, a coordinated program comprising three interconnected projects: upgrades to the Yan Yean Water Treatment Plant, construction of a new Transfer Pump Station, and the Yan Yean to Bald Hill Pipeline.
The treatment plant, originally commissioned in 1994, had been out of service since 2012 due to operational constraints. Over the course of five years, the SFPJV completed significant upgrades to restore the plant to full operation, replacing aging assets to meet current standards. The SFPJV also constructed a new Transfer Pump Station and delivered 9.1km of the 20km pipeline that now transfers potable water to Bald Hill Reservoir to support the broader reticulation network. These works were required to meet increasing demand in Melbourne’s northern suburbs, improve supply reliability and create additional capacity to transfer water to the west.
Scope of Works
The scope of work for the Yan Yean bundle included the following components for interconnected packages of work:
- Detailed design across all process, civil, mechanical, electrical, and control systems.
- Project management, design, construction, installation, commissioning, and operator training.
- Procurement and logistics of plant bulk materials and consumables.
- Provision of internal and specialist third-party labour, plant, equipment, supervision, and all other items necessary to complete the works.
- Dry, wet, and proof-of-performance commissioning of the treatment plant process, pump station, and transfer pipeline, including interface with the operational tank at Bald Hill and associated sub-systems.
- Operator training and support.
Yan Yean Water Treatment Plant
Between 2020 and 2025, significant upgrades were undertaken at the Yan Yean Water Treatment Plant. Early works included the completion of a power supply split, CO₂ system re-routing, temporary caustic dosing, and decommissioning. A comprehensive upgrade of ageing assets across the site was undertaken, including civil, mechanical, electrical, and control system components. Civil works were also delivered, including modifications to the inlet pipeline, the existing delay tank structure, filter inlet channel, additional below-ground pipework, new buildings for hypochlorite storage and ultraviolet (UV) disinfection, and access road upgrades. Mechanical works were carried out, including the installation of new mixers, pumps, dosing equipment, new filter media, and UV disinfection systems. Electrical and control systems upgrades comprised the replacement of low voltage switchboards, programmable logic controller control cubicles, and the installation of new drives, fibre optics, control wiring, and software. Additionally, building services were delivered, including fire services, CCTV, and access control systems.
Yan Yean Pump Station
Between 2022 and 2024, a new pump station was constructed at Yan Yean to transfer water to the Bald Hill Tank, housing multiple pumps and associated equipment. The team delivered the concrete pump housing, which was constructed from structural steel and precast concrete. Key mechanical installations included three 1 megawatt high-voltage (HV) pumps and two surge vessels to manage pressure fluctuations. The team also installed inlet and outlet main flow meters, high and low voltage switchboards, a high voltage transformer yard, and a generator hardstand. To minimise noise impact, acoustic treatment was also applied to the new pump station infrastructure.
Yan Yean to Bald Hill Pipeline
Between 2022 and 2024, the project team constructed a new 9.1km pipeline from the Yan Yean Reservoir to the Bald Hill Reservoir, designed to support water supply for Melbourne’s expanding northern and western suburbs. The pipeline comprised 9.1km of OD 972 mild steel cement-lined pipe, designed for durability and long-term performance. Two micro tunnel bores, measuring 200m and 50m in length, were completed beneath environmentally sensitive areas, including Merri Creek and the Melbourne to Sydney railway line, to minimise environmental impact. The civil works included concrete encasement and shoring. Welding was undertaken throughout the alignment, and the pipeline was installed at a steep gradient, which peaked at 29% at the top of Bald Hill. Other works included the installation of in-line butterfly valves, scour valves and air valves and the implementation of cathodic protection systems to prevent corrosion and extend the lifespan of the new pipeline.
Innovative solutions
The project team prioritised innovative solutions to optimise cost-efficiency, including the repurposing of existing infrastructure where feasible, while ensuring all technical requirements and client expectations were met.
Works at the water treatment plant were delivered under brownfield conditions and required close collaboration with multiple stakeholders to minimise disruption to ongoing operations.
SFPJV delivered 9.1km of the total 20km pipeline between Yan Yean Reservoir and Bald Hill Reservoir. As part of this package, two complex trenchless crossings were completed using the in-house tunnelling team and a Herrenknecht AVN1200 micro tunnel boring machine. Both drives were carried out through hard basalt rock, one beneath the environmentally sensitive Merri Creek and the other beneath a live rail corridor. By self-performing the tunnelling works through Abergeldie’s experienced specialist tunnelling team, the SFPJV reduced both risk and cost. The pipeline installation included 972mm diameter mild steel cement-lined PN35 pipe, laid at a peak gradient of 29% at the top of Bald Hill. The installation passed both pressure and water quality testing without any failures.
In total, the pipeline works achieved 427,090 work hours with zero Lost Time Injuries, reflecting the strong safety culture maintained on site.
Environment
The site crew implemented several sustainable practices, including harvesting rainwater for toilets, composting coffee grounds, and adopting a site cat for vermin control, which was later safely rehomed.
A circular economy approach was adopted for crushed rock, with recycled material used for haul roads onsite and later repurposed by the local council for community benefit.
Hydroseeding was carried out in stages to stabilise exposed ground shortly after disturbance. This process acted as both an erosion control measure and a way to help restore the area to its natural state.
Supporting future water demand in Melbourne’s north and west
Construction of the western section of the new pipeline from Yan Yean to Bald Hill Tank, along with the broader works at Yan Yean, was critical to supporting future development in Melbourne’s northern and western suburbs. With the city’s population growth expected to reach 6 million by 2031 and 8 million by 2051, this project was designed to cater for the growing demand, improve supply reliability, address shortages, and ensure a sustainable water source for the community.
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Safety Focused Performance Joint Venture (SFPJV)
