The Hawkesbury-Nepean River system is one of New South Wales’ most valuable natural assets. It supports a $600 million irrigated agricultural industry, a $6.3 million fishing trade, and draws around 10 million tourists each year to its unique ecosystems. Protecting a river system of this importance — while easing pressure on Sydney’s main drinking water supply — was the goal behind the Western Sydney Replacement Flows Project. To build the pipeline network at the heart of it, Sydney Water turned to Viadux.
A Cornerstone of Sydney’s Metropolitan Water Plan
The project formed a key element of the NSW Government’s Metropolitan Water Plan, a broad strategy aimed at securing Sydney’s water supply for the long term. At its centre was the $209 million St Marys Water Recycling Project, which combined a state-of-the-art water recycling plant at St Marys with a network of major pipelines to distribute the recycled flows.
The scale of what the plant was designed to achieve is striking. The St Marys Water Recycling Plant was built to deliver up to 18 billion litres of high-quality recycled water into the Hawkesbury-Nepean River system every year — a volume substantial enough to make a real difference to how Sydney manages its water.
Replacing Dam Releases with Recycled Flows
The clever idea underpinning the project was substitution. The recycled flows generated by the plant were designed to replace water releases from Warragamba Dam, Sydney’s primary water source. By pumping treated recycled water into the river system instead of releasing dam water, the project effectively freed up a significant volume of Sydney’s drinking water reserves — a major win for a growing city facing long-term supply pressures.
There was an environmental dividend, too. Beyond easing demand on Warragamba Dam, the project was designed to reduce the volume of nutrients being discharged into the river, helping to protect the health of the waterway and the industries and ecosystems that depend on it.
Why Sydney Water Chose Viadux
For a project tasked with safeguarding such a valuable and sensitive river system, product quality was non-negotiable. Viadux was contracted to supply and deliver over 50 kilometres of TYTON ductile iron pipe and SUREFLOW fittings, in sizes ranging from DN300 to DN600.
The selection wasn’t made on price alone. Viadux was chosen based on its commitment to quality and the extended service life of its products — qualities that were essential given the pipeline’s role in protecting a river system underpinning hundreds of millions of dollars in economic activity. When a pipeline failure could threaten agriculture, fisheries and tourism alike, the durability of every pipe and fitting matters enormously. It’s the same standard of quality that runs across the entire Viadux product range.
Delivering at Scale: Over 7,000 Pipes
The numbers behind the supply effort underline just how large this project was. Viadux delivered in excess of 7,000 individual pipes, along with more than 1,000 fittings and fixtures — together forming an Australian-made pipeline over 50 kilometres long.
Coordinating a supply program of this magnitude, across multiple pipe diameters and to exacting specifications, is no small undertaking. Viadux was well prepared to meet the demanding volume and specifications of the order, drawing on more than 100 years of experience and expert knowledge in supplying pipeline systems across Australia. That depth of experience is what allows Viadux to take on nation-building infrastructure with confidence, as it has on projects like the SEQ Water Grid and the Bega Valley Pipeline.
Proudly Australian Made
A notable feature of the project was its Australian-made pipeline. At a time when local manufacturing capability is increasingly valued in major infrastructure procurement, the use of Australian-made pipe supported domestic industry while giving Sydney Water full confidence in the provenance, quality and consistency of the materials going into the ground.
A Model for Large-Scale Water Projects
With deliveries beginning in July 2008, the successful completion of the St Marys Water Recycling Project stands as a fine example of the water industry’s ability to combine its capabilities and deliver large-scale projects to the community — safely, on time, under budget, and meeting all quality requirements.
For Sydney, the legacy is a more secure and sustainable water future: reduced reliance on Warragamba Dam, a healthier Hawkesbury-Nepean River, and a recycling model that other cities can learn from.
Partner With Viadux on Your Next Water Project
From recycled water schemes to bulk transfer pipelines, Viadux brings the products, the manufacturing capability and the major projects experience to deliver at scale. Explore more of our industry case studies, learn more about Viadux, or contact our team on 1300 VIADUX (842 389) to discuss your requirements.