31 January 2025
Thornleigh pipeline duplication community update – February 2025
In 2024, 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 2 years to complete.
Upcoming investigation work
To help us plan these upgrades, we need to carry out investigation work in the area from February 2025 and expect this to take 3 weeks to finish, weather permitting. Our working hours are Monday to Friday from 7am to 6pm, and Saturdays from 8am to 1pm. Work has commenced within Sydney Water's grounds at Thornleigh Reservoir on Quarter Sessions Road, Westleigh, and will soon start at Thornleigh-Wahroonga Water Pumping Station on Dale Close.
Activities include site surveying, service locating, soil sampling and groundwater assessments. In order to plan work, surveying will be carried out using a drone. This will allow the collection of accurate geospatial details to refine the pipeline design. Please note: the use of a drone over the work area, including private property, is not intended for the general collection of information – only for geospatial data – and will be treated confidentially. There will be some noise and dust from the digging and machinery at the reservoir, but we will make every effort to reduce the impact this work may have on you.
Ironbark Joint Venture will be establishing site compounds at Thornleigh Reservoir and Thornleigh-Wahroonga Water Pumping Station (on Dale Close) from Monday 10 February 2025.
This will include:
- Delivery and installation of offices and portable facilities.
- Delivery of materials and plant.
- Creation of access roads, and car parking, and associated earthworks.
- Installation of hoarding around sites and acoustic barriers around generators to reduce noise impacts.
- Concreting of site areas.
- Clearing of trees and vegetation around our work sites.
- Trimming of some street trees to allow for larger vehicles to access the site.
- Parking and minor traffic changes to Edmundson Close and Dale Close. We will provide additional details of these changes to impacted residents. Private property access will be maintained throughout the project.
- Work around Edmundson Close and Zig Zag Creek to allow for heavy vehicle access, including road and pedestrian path modifications.
In addition, we need to undertake potholing work on Giblett Avenue and Edmundson Close, and within the Thornleigh-Wahroonga Water Pumping Station site. This work is planned to start early February and will take approximately 3 days per site, weather permitting. The potholing work will help us identify the location of underground utilities. To carry out this work, there will be temporary traffic changes, with traffic controls in place around designated pothole work areas to guide motorists and pedestrians. Please follow directions from the traffic controllers and signs.
We aim to minimise community impacts by:
- fencing our work site for safety and security
- using quieter equipment where possible
- turning off equipment when not in use
- taking deliveries during quieter periods
- covering loads and any stockpiles
- using a water cart where necessary to reduce dust.
What's happening next?
Once we establish our site compounds, Ironbark Joint Venture will begin excavating pits at the Thornleigh Reservoir and Thornleigh-Wahroonga Water Pumping Station sites so that tunnelling can commence in the coming months.
If you'd like to know more about the work, please contact the community engagement team at thornleighiom@sydneywater.com.au or call 1800 112 480.
Your feedback
Sydney Water would like to thank the community for the feedback and questions in response to the REF. Below is a summary of our response to the main themes raised as part of this consultation. For more detailed responses, please view or download the Decision Report.
Impacts from vegetation removal associated with the access road at the reservoir
The existing internal access road on Sydney Water land near Quarter Sessions Road will need to be widened to 6 metres. This will require some vegetation removal. There is no suitable option closer to the embankment that would allow heavy vehicle access. This includes the side slopes that connect the road surface to the surrounding land area. Although some vegetation trimming and removal is unavoidable, we will ensure that the impacts are minimised.
Noise and vibration impacts
We will use hoarding equipment around sites and acoustic barriers around generators to reduce noise impacts. We will keep the community informed about what to expect throughout the work.
Impacts to the Edmundson Close walkway
The safety of the local community and our workers is a top priority. To ensure work can be carried out in a safe manner, we'll need to change some local access. The construction contractor will prepare a traffic and pedestrian management plan around work sites. Temporary adjustments will be required to access around Edmundson Close. Once construction is complete, pedestrian access to the Edmundson Close walkway will be available again.
Impacts to flora and fauna
To allow safe access to the site, some vegetation removal south-east of Thornleigh Reservoir is required. We have minimised vegetation removal by making the launch shaft and surrounding storage area as small as possible. We will minimise vegetation removal where possible.
Community sessions
You can meet the project team at one of our 2 community sessions.
Tuesday 18 February 2025 6pm–8pm
Sanctuary Gardens Clubhouse
The Sanctuary, Westleigh 2120– please note that the clubhouse is only open to Sanctuary Garden residents.
Wednesday 19 February 2025 3pm–5pm
Thornleigh Squash Club
206 Duffy Avenue, Thornleigh 2120
