What we're doing
Melbourne Water is replacing a section of the existing Melbourne Main Sewer. The new main sewer will travel approximately 2.3km from Docklands, crossing the Yarra River upstream of the Charles Grimes Bridge, and into Port Melbourne.
The Melbourne Main Sewer Replacement is an important project that will deliver health and environmental benefits to meet the future growth of Melbourne.
Melbourne's sewer connection to the Western Treatment Plant
Why?
The original Melbourne Main Sewer was built between 1894 and 1897. While it has served the CBD and inner suburbs including Port Melbourne well, the sewer needs replacing due to its age and capacity to keep up with urban growth.
How long will the project take?
Construction of the project began in late August 2008 and is due to be completed in 2012. Visit our project timeline page for timing of key works.
Construction of the new sewer
The new sewer will be constructed using a tunnel boring machine with most work taking place at least 10 metres underground. Six vertical access shafts sites between 10 to 15 metres deep will be excavated along the sewer corridor. These shafts will act as manholes once the sewer is complete.
A tunnel boring machine will be used to excavate tunnels through a variety of ground conditions. It can bore through hard rock, sand and most other materials.
The advantage of using a tunnel boring machine is that it minimises disturbance to the surrounding soil, making it suitable to use in built-up urban areas.
During the Melbourne Main Sewer Replacement, the tunnel boring machine will tunnel through a variety of material including, Coode Island Silt, sandy clay and basalt clay.
Crossing the Yarra River
A major component of the Melbourne Main Sewer Replacement is the crossing of the Yarra River, upstream from the Charles Grimes Bridge.
The river crossing will be completed in three sections using a cofferdam construction method. Working from the south bank to the north bank, each of the three sections will take approximately eight months to complete. For more information see constructing the river crossing.
Local connection works
During the project, approximately 2.5km of new local branch and reticulation sewers will be constructed to reconnect the existing local sewers into the new Melbourne Main Sewer. Smaller, short-term shaft sites in local streets will be used to complete the work. This may cause some disruption to local traffic with temporary partial road closures. Road closures will be communicated to the local community closer to work occurring.
Cost of the sewer replacement
The total cost of the Melbourne Main Sewer Replacement is estimated at $220 million and will be funded by the Victorian State Government.
Further information
