Western Trunk Sewer Upgrade Project

We’re upgrading the Western Trunk Sewer, a vital part of our sewerage network that has reached the end of its service life. Relining the sewer ensures a safe sewerage service for local homes and businesses – today, tomorrow and for generations to come.

Why is this important?

Built in the late 1980s, the 4.5m-diameter sewer transfers 57% of Melbourne’s sewage to the Western Treatment Plant in Werribee for treatment.

It consists of:

15.2km of deep tunnel from Brooklyn Pumping Station to Hoppers Crossing Pumping Station
7.2km of shallow tunnel from Hoppers Crossing Pumping Station to the Western Treatment Plant.

Our regular inspection program has identified some sections that are reaching the end of their working life.

Western Trunk Sewer upgrade project alignment

What’s happening?

We will be relining 4.4kms of the shallow tunnel between Hoppers Crossing Pumping Station to the Western Treatment Plant, using a trenchless rehabilitation method. We’ll also rehabilitate 14 maintenance holes.

What to expect

Utilising ‘trenchless’ technology

To upgrade the sewer, we will use one of two trenchless technology techniques. These allow us to reline the inside of the existing sewer with new plastic sleeving or pipe without having to dig it up.

This has several benefits, including:

greatly reducing the impacts on the important cultural and environmental values of the landscape we are working in.
ensuring that disruptions and inconveniences at street level are kept to a minimum, and residents and businesses don’t have to worry about open trenches on their doorsteps
allowing upgrade works to be completed more quickly and efficiently compared to traditional trenching methods
ensuring the structural integrity of the sewer is maintained for decades to come.

Access tracks to maintenance holes

To complete the works, we must create access tracks for construction vehicles and machinery so they can safely and efficiently get to the maintenance holes. This may require earthworks in some areas due to the landscape.

Some access tracks will remain in place to enable ongoing maintenance activities to be performed safely. All temporary access tracks will be reinstated and planted over with grasses.

Construction impacts

As a guide, we have listed a number of potential impacts that you may notice during major construction works:

Night works are needed for some of the relining works, as this is when sewage flows and traffic flows are at their lowest.
Noise: There will be a short-term increase in noise in the area, but we will do as much as possible to reduce the construction noise. We will monitor noise and dust levels throughout works to ensure they don’t exceed Environmental Performance Agency thresholds.
Odour: Some odour is expected when carrying out the works due to harmless gases escaping from the maintenance holes when they are opened. We aim to minimise and localise this as much as possible.
Traffic, parking, cyclists, and pedestrians: There will be temporary changes to traffic conditions, including lane closures, road closures and parking restrictions. For your safety, work areas will be fenced, restricting access, while work is being completed. We encourage you to follow all directions and take care around work areas.
Cultural heritage: Cultural heritage conservation is an important part of valuing and preserving our traditions and culture. We will comply with the Heritage Act as we deliver the works and engage with Traditional Owners throughout the project.
Environment: To safely access maintenance holes, there will be some instances where trees and vegetation need to be trimmed or removed.

We will make every effort to minimise the impact of these works on the local community and environment.

Reinstatement of affected areas

After the works are complete, we will focus on reinstating and rehabilitating areas affected by our work. This includes re-grassing and replanting, which will be undertaken in accordance with plans approved by Council and Parks Victoria.

When will we be working?

Works will be undertaken at the following times:

Night works: 9pm to 7am, Sunday to Thursday
Day works: 7am to 6pm, Monday to Friday
Weekend hours: 9am to 3pm, Saturdays (if required).

We may occasionally need to undertake works out of hours. We will notify you in advance if this is required. Due to weather conditions and fluctuating sewer flows, the timing and dates are indicative and subject to change without notice.

Thank you for your understanding and patience during these essential works.