We’re replacing the sewer siphon that transfers sewage under the Yarra River, as part of the second phase of works on the Hawthorn Main Sewer upgrade.
Why this is important
The Hawthorn Main Sewer is a vital part of Melbourne’s infrastructure, constructed over 100 years ago in 1903. It transfers sewage to the Western Treatment Plant in Werribee for treatment.
To keep this vital asset functioning into the future, works are needed to replace the existing Hawthorn Main Sewer Siphon that runs under the Yarra River. A siphon is a wastewater pipe that enables sewage flows under low-lying areas or obstructions like rivers, where flow by gravity is difficult.
What’s happening and when
We are replacing the sewer siphon and decommissioning the existing asset. This involves using a tunnel boring machine (TBM), which bores through the ground and progressively installs large concrete ‘jacking’ pipes behind it. These pipes will host the new sewer siphon.
The process involves:
- Excavating shafts on Creswick Street (Hawthorn) and Murphy Street (Richmond) to launch a tunnel boring machine.
- Lowering a machine into the Hawthorn shaft, from where it will tunnel towards the Richmond shaft.
- Pumping excavated material from the machine’s face to the surface, where the slurry material is separated. The liquid is recycled back into the machine and the solid material is removed from site by trucks.
- Completing the new sewer siphon, which is housed in the jacking pipes installed behind the TBM.
- Connecting the new siphon to the existing network, and decommissioning the old asset.
Mid-March to Sept/Oct 2021
Late March/early April 2021
Piling - Richmond side only.
Sept/Oct 2021 to Jan 2022
Jan 2022 to Apr/May 2022
Pipe install in tunnel and backfill.
June to Oct/Nov 2022
Hand tunnel between new and existing asset; includes two weeks of tie-in works to existing asset.
Reinstatement activities - to be completed by early 2023.
What to expect
We do not anticipate any impacts to your water or sewerage services during the works.
If you experience an issue with your sewerage service, contact your water retailer: Yarra Valley Water (132 762) or City West Water (132 642).
Where possible, the team will seek to minimise impacts and inconveniences. Further details of the expected experience of our works can be found below.
- Work hours:
- Monday to Friday, 7am to 6pm
- Saturday as required, between 7am and 1pm
Quiet work outside these hours will include arriving at site, tidying up, office work and checking on site safety.
- Night works: will be needed for approximately 1 to 2 weeks to connect the new and existing manholes as quickly as possible. Most work will take place underground.
Every effort has been made to limit tunnelling works to weekdays during the day. However, if conditions change and the tunnel is at risk we will need to convert to 24/7 operation. The likelihood of this taking place is low.
- Noise: the works will be noisy, particularly the shaft excavation (including piling) and above-ground activity needed for tunnelling. We will implement mitigation measures where possible.
- Odour: no odour is expected during most of the works. The only time a minimal amount of odour may be experienced is when the new sewer pipe is connected to the existing manhole.
- Vibration: shaft excavation and piling will cause vibration, and real-time vibration monitors will be in place to manage the levels and where it is experienced. We do not expect vibration to impact nearby properties.
- Traffic changes:
- Creswick Street will be closed to traffic at Bridge Road and Denham Street.
- Murphy Street will be closed to traffic between River Street and the Yarra River’s embankment.
- Driveways: we expect to maintain private property driveway access, but will notify you if short-term driveway closure is needed.
- Rowing clubs: access at Denham Street and Creswick Street will be maintained for most of the works. We will notify the rowing clubs if the driveway is to be closed due to works at the existing manhole.
- Footpaths: one footpath on Creswick Street between Bridge Road and Denham Street will be closed.
- Hawthorn: most truck traffic will access the site from Bridge Road. Some vehicles will need to access from Denham and Creswick Streets – we will limit this when possible.
- Richmond: access to the site will be via River Street, Murphy Street and Crown Street.
If you have feedback or would like more information about this project, contact us: