Before tunnelling for the West Gate Tunnel Project begins in 2019, we need to divert a 600 metre section of the North Yarra Main Sewer. Diverting a sewer is a massive job that involves excavation, piling, tunnel boring and changes to traffic – and we’re going to build it without interruption to sewerage services during the diversion works.

Latest update: Mollie has finished digging

Mollie the mini tunnel boring machine (TBM) has now finished digging a new sewer line underneath Yarraville.

Here's what Mollie achieved:

  • 35 days of digging
  • 424 metres of tunnel boring under Yarraville
  • 3,174 cubic metres of dirt excavated

What's next: connection works to the new sewer will be ongoing until mid-2019.

More info: keep reading below for more about Mollie and the North Yarra Main Sewer.

About the North Yarra Main Sewer

The existing North Yarra Main Sewer is 2.6m in diameter, over 100 years old and made mostly of bricks.

The sewer runs below the centre of Whitehall Street in Footscray and Yarraville, and it carries 20% of Melbourne’s sewage.

About Mollie

To keep the old sewer operating all the time, a mini tunnel boring machine (TBM) called Mollie will create a route for the new sewer. As the mini TBM moves through the earth at the rate of about 12 metres a day, glass reinforced plastic lining is installed around the tunnels to seal it and strengthen the structure.

Once the new sewer is ready to operate, a gap will be opened in the wall of the old sewer so sewage can start flowing via the new tunnel.

When the diversion is built, over 9,000 cubic metres (3.6 Olympic size swimming pools) will have been excavated.

See the moment Mollie breaks through

We caught the West Gate Tunnel Project's first TBM breakthrough on film - watch the video to find out more about Mollie and diverting the North Yarra Main Sewer.

Yarraville and Footscray: What you will see

Worksites have been established on Whitehall Street, and there are significant changes to traffic between Leek Street, Yarraville, and Parker Street, Footscray.

The safety of all road users and our workforce is a priority. Detours are in place and safety measures including temporary barriers provide crews the access and space needed on Whitehall Street.

These changes started from August 2018 and will be in place for approximately 12 months.

Program of works for North Yarra Main Sewer diversion. Click image to enlarge.

Travel changes near the project

During works, there are some unavoidable disruptions in the local area for motorists, cyclists and pedestrians.

We have worked closely with local businesses and residents to plan these traffic changes, and continue to work with them to plan and manage construction and traffic impacts as best as possible.

Please be aware of the following changes during construction:

  • Whitehall Street is closed northbound between Leek Street and Somerville Road until August 2019 (see yellow line in map below).
  • Whitehall Street reduced to one lane in both directions between Parker Street and Somerville Road (see blue line in map below).
  • bike lanes on Whitehall Street closed between Somerville Road and Parker Street. Cyclists detour via the Hyde Street path (see pink line in map below).
  • oversize vehicles no longer able to travel on Whitehall Street. Detour via Napier Street and Hyde Street.

Key travel changes are shown in the detour map below. See the factsheet (PDF, 3 MB) for more details.

Travel changes during North Yarra Main Sewer diversion works.

Keeping you moving

We will minimise disruption as much as possible and keep you informed through:

  • clear signage and traffic controllers to direct traffic
  • providing regular updates about our works
  • increased monitoring and support for enforcement of truck curfews and local destination exemptions.

More information

For more details, see the North Yarra Main Sewer diversion factsheet (PDF, 3 MB).

If you have any questions, our team is available 24 hours a day on 1800 105 105.

See upcoming travel disruptions and recent construction notifications.

Find out why we need to divert the North Yarra Main Sewer