Melbourne Water has completed upgrade works to the Maribyrnong River Main (MRM) sewer, which transports approximately 24 million litres of wastewater each day to the Western Treatment Plant.
Melbourne Water and our project delivery partners, CPB and Black & Veatch Joint Venture, thank residents and local businesses for their patience and understanding throughout these upgrade works, which began in mid-2018 and were completed in March 2020.
We also thank Moonee Valley City Council, Parks Victoria, Wurundjeri Land Council, Friends of Maribyrnong Valley and Friends of Steele Creek for working with us to ensure the successful delivery of the project. We could not have completed this important sewer upgrade without these strong partnerships.
Why this project was important
The MRM is one of the main sewers in Melbourne Water’s 400 kilometre network. Each day, it transports approximately 24 million litres of sewage from 36,000 properties in the north-western suburbs of Melbourne to the Western Treatment Plant in Werribee.
Built in stages between 1963 and 1977, some sections of the sewer were coming to the end of their working life. Upgrading the sewer was an important initiative for the residents of the north-west suburbs as it will ensure the sewer continues to provide the community with a secure and reliable sewerage service for decades to come.
This project was part of Melbourne Water's four-year sewer relining and manhole rehabilitation program to upgrade 15 kilometres of ageing sewers across Melbourne. The upgrade will extend the life of the Maribyrnong River Main sewer for at least another 50 years.
What we did
Melbourne Water upgraded 7.2 kilometres of the Maribyrnong River Main (MRM) sewer in Avondale Heights, Essendon West and Aberfeldie. Upgrading the sewer involved:
- constructing temporary and permanent access tracks to manholes
- cleaning and relining the sewer by inserting a new plastic sleeve into the existing pipe
- filling the gap between the existing pipe and new sewer liner with cement (grouting)
- rehabilitating ageing and damaged manholes and decommissioning some that were no longer needed.
Throughout the upgrade works we ensured there were no impacts or interruptions to your water or sewerage services. To do this, we installed temporary above-ground sewer bypass pipelines to allow local services to keep operating at all times.
Completed works ahead of schedule
We anticipated that the upgrade works would be completed by mid-2020; however, this was achieved much earlier than planned. We did this by having a number of crews working in multiple locations at the same time, which allowed us to complete the works more quickly and efficiently.
Utilising 'trenchless' technology
To upgrade the sewer, we used a trenchless technology technique called ‘relining’. This technology allowed us to reline the inside of the existing sewer with new plastic sleeving without having to dig it up, which had a number of benefits including:
- significantly reducing the impacts to the important cultural and environmental values of the landscape we were working in
- ensuring that disruptions and inconveniences at street level were kept to a minimum, and residents and businesses didn’t have to worry about open trenches on their doorsteps
- allowing the 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 manholes
Some of the manholes are located in areas of steep and difficult terrain; these can be up to 40 metres deep (equivalent to the height of a 15-storey building).
Access tracks for construction vehicles and machinery needed to be created so we could safely and efficiently get to the manholes to complete the works. This required significant earthworks in some areas due to the landscape. Some of these access tracks will remain in place to enable ongoing maintenance activities to be performed safely into the future.
All temporary access tracks will be reinstated and planted over with grasses.
Respecting local heritage and the environment
Throughout the project, we worked closely with Moonee Valley City Council, Parks Victoria, Wurundjeri Land Council and community groups to manage the upgrade works, and to ensure the significant cultural heritage and ecological values of the local area were protected.
Project-specific environmental management plans were in place to protect native plants and animals throughout all of our work activities. A cultural heritage management plan was also in place during the entire project.
The project was carefully designed to avoid impacts to as many trees and shrubs as possible, and we worked in close partnership with Council and Parks Victoria to minimise the amount of vegetation that needed to be removed.
We are now working to replace all the vegetation (mainly grasses) where removal was unavoidable. We will be leaving a lasting legacy by enhancing the environment and amenity of the local area through native plantings.
Reinstating affected areas
We are now focussing on reinstating areas affected by our work activities. Over the coming weeks, we will be re-grassing and re-planting in the local region to rehabilitate disturbed areas. This will be undertaken in accordance with revegetation and reinstatement plans approved by Council and Parks Victoria. Local input to the revegetation plans was also provided by the Friends of Steele Creek and Friends of Maribyrnong Valley.
Other areas affected by our works will be restored to their original level of amenity or similar condition. Reinstatement will be inspected by Moonee Valley City Council to ensure community safety and well-being.
Replanting in the local area
In April-June 2020, we’ll be reinstating and re-grassing areas disturbed by our works. We’ll also be planting more than 10,000 native trees, shrubs and grasses in the local region, building on and complimenting other revegetation works undertaken by Parks Victoria, Friends groups and Moonee Valley City Council.
A weed control program will also be implemented over the next two years, targeting a range of high-threat weeds including boxthorn, prickly pear, thistles, blackberry, desert ash and others. These weeds will be replaced with native vegetation to provide habitat for birds and other animals.
For the next two years, we’ll closely monitor the newly planted vegetation, watering them particularly over the summer months, and controlling encroaching weeds to ensure their best chance of survival.
If you would like more information about the reinstatement works or re-planting in the local area, please contact Melbourne Water on 131 722 or [email protected].