Sustainability Report 2006/07Sewerage transfer
Landmark sewer projects begin
Works began on a five-year sewerage project that will cater for substantial growth in Melbourne’s northern suburbs and protect and improve local waterways from sewage spills that can occur after heavy rain.
The $650 million Northern Sewerage Project involves the construction of 13 kilometres of deep tunnel sewers along the Merri Creek Valley from Coburg to Reservoir and the Moonee Ponds Creek at Pascoe Vale.
Construction is in two stages, with the first managed by Melbourne Water and the second by Yarra Valley Water. Work began on Stage 1 in August and Stage 2 the following month. The project is scheduled to be completed in mid-2012.
Most construction is taking place 15 to 64 metres below ground. Tunnel-boring machines are being used to build the tunnels, which are then lined to create the sewer pipes.
This year, construction began at all five Stage 1 shaft sites: Brearley Reserve near Bell Street in Pascoe Vale; De Chene Reserve, Coburg; Carr Street, North Coburg; Vanberg Road, Essendon; and Bass Street, Pascoe Vale South.
The De Chene Reserve shaft was completed in May and the first of two Stage 1 tunnel-boring machines was launched and began tunnelling towards Carr Street.
Melbourne Water is replacing a section of the 110-year-old Melbourne Main Sewer to meet increased capacity of the central business district and the Docklands.
A new 2.4-kilometre sewer is being built from the Docklands to Swallow Street in Port Melbourne, where it will connect to the Hobsons Bay main sewer. The project includes a crossing of the Yarra River upstream of the Charles Grimes Bridge.
To build the sewer, six shaft sites, between 10 and 15 metres deep, will be excavated. The shaft sites will enable the use of tunnel-boring machine technology and pipe-jacking methods.
Construction is due to begin in August 2008 and is scheduled to be completed in 2012.
Managing odour
Melbourne Water conducted an odour risk assessment across the sewerage transfer system, with sites ranked according to criteria including odour complaint history, hydrogen sulphide monitoring, corrosion data and ventilation status.
The assessment identified several priority sites requiring risk mitigation works. These are at Box Hill South, Carlton, Port Melbourne, Footscray and East Brighton. Odour control and treatment facilities will be constructed at these sites over the next five years.