The tunneling is a major milestone for Victoria's desalination plant which remains on time and on budget.
Unlike most desalination plants around the world, Victoria's intake and outlet tunnels are being built 15 to 20 meters underneath sand dunes and the seabed to ensure the marine environment is protected.
Premier John Brumby and Water Minister Tim Holding today visited the desalination plant site at Wonthaggi to inspect the two tunnel boring machines being used to construct the tunnels.
Work is about to start on the 1.5 km long outlet tunnel while the first machine has bored 130 meters of the 1.2 km long intake tunnel.
Mr Brumby said the desalination plant, which will provide up to 150 billion liters of water from the end of 2011 regardless of rainfall, was Victoria's insurance policy against future droughts and climate change.
"Victorians are doing their bit by restricting water use to less than 155 lites a day and our Government has taken the tough decisions to invest in water projects right across the State.
"The desalination plant allows us to ease water restrictions and ensures we will not have to put restrictions back up again.
"We have listened to the local community and chosen to build the desalination plant's tunnels deep underground to protect marine life and the surrounding environment.
"We have also committed to fully offset the power required to operate the plant and pipeline through the purchase of renewable energy.
"The project remains on schedule to begin supplying water to Melbourne, Geelong and regional towns in South Gippsland and Western Port from the end of next year."
The custom-built tunnel boring machines are 4.8 metres wide, 91 meters long and weigh more than 500 tonnes each.
The tunnel boring machine will excavate through heavy rock and will line the tunnel with concrete segments. Both tunnels are expected to be completed early next year.
The intake tunnel will draw seawater into the plant where it will be desalinated. The drinking water will be pumped to Melbourne, and the seawater concentrate will be discharged back into Bass Strait via the outlet tunnel where it will be easily dispersed.
Mr Holding said Victoria had set high international standards for the project with strict environmental safeguards in place for the private consortium building the project.
"We completed one of the most comprehensive environmental effects studies ever undertaken in Victoria's history which will ensure marine life and the surrounding environment are protected," Mr Holding said.
Mr Holding said together with the Food Bowl Modernisation Project and Sugarloaf Pipeline, the desalination plant was Victoria's roadmap back from severe water restrictions.
"We have recently eased water restrictions to Stage 2 in Melbourne and Geelong and more than half of our towns don't have any water restrictions. Whilst water use is still restricted under Stage 2, it provides more flexibility and was possible due to our major water projects, welcome rainfall and community water saving efforts."
Significant progress has been made on the desalination plant site since Thiess Degrémont, the design and construction contractor for AquaSure, began work in September 2009:
• There are more than 3000 people working on the project including more than 1600 people on the plant site;
• Bulk earthworks are now complete, with more than 1.3 million cubic meters of earth removed to create new dunes, and more than 15,000m3 of structural concrete poured;
• The reverse osmosis building has begun to take shape, with more than 1000 tonnes (more than 30 per cent) of structural steel now erected; and
• More than a third of the 84 km Victorian manufactured pipeline that will carry desalinated water to Melbourne has been laid. Around 24km of power supply conduit has been laid, with 24.7km of the Victorian manufactured cable pulled through.
Mr Holding said the desalination plant was now one of the largest employers in the region and was delivering significant benefits to the Victorian economy.
"More than $1.1 billion in contracts have been awarded on the project to date, with more than three quarters going to Australian companies and two thirds to Victorian suppliers," he said.
Mr Holding also announced two local school students won a competition to name the tunnel boring machines.
"Jakob Moon, 6, from Traralgon, the son of a project worker, named the intake machine 'Wonthaggi Maggie' and Mycalie James, 18, from Bass Coast Specialist School named the outlet machine 'Rocking Ruby'," he said.