FAQs
What stage is the project at?
Last year, we consulted on the Review of Environment Factors (REF) and gained valuable feedback from the community on the project. We have outlined the main themes raised below. Responses to the feedback we received can be found in the Decision Report for the REF, which is published on this page. The recommendation is for the project to proceed with additional mitigation measures.
Ironbark Joint Venture, a partnership between Bouygues Construction Australia and Rob Carr Pty Ltd will deliver the project on behalf of Sydney Water. Site establishment will commence in February 2025, with major construction expected to start later in the year. This will take around two years to complete.
What are the benefits of the duplicated pipeline?
We are investing now to transform and integrate our water, wastewater, stormwater, and recycled water systems to ensure we can continue to provide safe, reliable and affordable services to customers as the region continues to grow.
The proposed pipeline will increase the resilience of local water supply by allowing water to be transferred between Thornleigh Reservoir and Thornleigh-Wahroonga Water Pumping Station to cater for the growing population.
This is not just about pipes. It's about water - clean, life sustaining water. Our work will ensure we can continue to give you clean and reliable water as the area continues to grow.
How long is the proposed pipeline?
The proposed pipeline will start at Thornleigh Reservoir in the south-east corner of the site. It will then be tunneled around 1.2 km to the south side of Zig-Zag Creek at Thornleigh-Wahroonga Water Pumping Station.
The new pipeline is the same diameter (180cm) and will run parallel to the existing pipeline. Like the existing pipeline, the new pipeline will run under private properties and cross local roads between 14 and 38 metres below ground level.
Will I be impacted by the works?
The proposed pipeline will benefit residents in the area where the population is expected to increase to 2.26 million by 2026. A trench-less construction method is proposed to reduce any impact on private property. We will provide residents with an update about the proposed works and timing prior to any construction works.
Will the pipeline pass under properties?
The new pipeline is the same diameter (180cm) and will run parallel to the existing pipeline. Like the existing pipeline, it will run under private properties and cross local roads between 14 and 38 metres below ground level.
Approximately 160 metres will be trenched within the Sydney Water owned Thornleigh Reservoir site and the remaining 1.2km of the pipeline will be tunneled using a small tunnel-boring machine. The tunnel-boring machine uses a ‘trenchless’ construction method to reduce the impacts on the environment and the community.