Preparing for pipeline completion at the Victorian Desalination Project
The Australian Pipeliner — October 2011
Construction of the 84 km transfer pipeline for the $3.5 billion Victorian Desalination Project is almost complete.
Comprising 6,770 sections of 1.93 m diameter mild steel cement-lined (MSCL) pipe, the pipeline will be capable of transferring up to 200 GL/a of water from the desalination plant to Melbourne and regional communities.
The pipeline, which can operate in reverse flow, contains seven water delivery points that can supply water to customers in Melbourne, South Gippsland and Western Port towns. Other infrastructure includes a booster pump station at Clyde and surge tanks in The Gurdies and Kilcunda Ridge.
With an initial pumping capacity of 444 ML/d, the pipeline is designed to have up to a 600 ML/d ultimate flow rate.
Completion of the pipeline represents a significant achievement for the Victorian Desalination Project, and reflects the teamwork and commitment to high quality, safety, environmental and community standards of pipeline construction contractor Thiess Degrémont Nacap Joint Venture.
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At its peak, 11 different pipeline crews were working at one time along the 84 km pipeline route, comprising two mainline crews, two smaller mainline crews for difficult terrain, three special crossing crews for road and river crossings, three pipe jack crews and valve installation crews, plus an additional crew working to connect the pipeline with the Melbourne Water network in Berwick.
The route included 45 road crossings and 21 major waterway crossings completed using a combination of pipe-jacking and open-cut trenching, and day-to-day liaison with approximately 125 directly-affected and 400 indirectly-affected landholders.
With the pipeline passing through large stretches of rural and agricultural areas, installing the pipeline as quickly and safely as possible while minimising disruption to landholders and surrounding communities was a high priority.
Construction varies from an 800 mm minimum depth of cover to an 11.2 m maximum depth of cover at the Bass River – one of five pipe-jack crossings along the pipeline.
The team also faced the combined challenges of installing the pipeline during winter months and periods of record rainfall, summer floods, and construction through areas of difficult terrain including two significant steep sections through The Gurdies and Kilcunda Ridge.
Project Manager Graeme Tait said “We adopted a flexible approach during the winter period, focusing our efforts on drier areas and maximising productivity during spells of positive weather.”
“Having multiple work crews in place meant we could take advantage of the best ground conditions and concentrate our efforts there, while minimising disruptions to landholders and surrounding communities.”
Victorian Desalination Project: pipeline summary
84 km long pipeline, capable of transporting up to 200 GL/a if required
Comprises 6,770 sections of 1.93 m mild steel cement-lined pipe, each section generally 13.5 m long and weighing approximately 13 t
Over 14,000 pipe welds using flux core arc welds
45 road crossings and 21 major waterway crossings, including major crossings of the Bass and South Gippsland Highways and the Bass and Powlett Rivers, using a combination of pipe jacking and open-cut trenching
Pipes supplied by Victorian firm Tyco Water, using BlueScope Steel, with a total value of pipes being $150 million
Day-to-day liaison with around 125 directly-affected and
400 indirectly-affected landholders.
Pipeline statistics Length: 83,400 m Diameter: 1.93 m Pipeline volume: 243 ML/d Peak design flow-rate: 444 ML/d initial pumping capacity. Pipeline is designed to 600 ML/d ultimate Operating pressure: 25 bar, approximate to 250 m depth of water Test Pressure: 30 Bar, approximate to 300 m depth of water Wall thickness: Standard 12.5 mm; heavy wall up to 32.0 mm Steel grade: Grade 300 and Grade 350 mild steel cement-lined pipe Minimum depth of cover: 800 mm Maximum depth of cover: 11.2 m at Bass River Number of pipes lengths: 6,770 Truckloads of pipe: 6,500 Quantity of welding wire: 75,000 kg Bedding and haunching sand imported: 800,000 t Soil removed from the site: 1,450,000 cubic m Right-of-way area: 3,350,000 sq m Topsoil stripped and replaced: 837,000 cubic metres Micro-tunnelled crossings: 5, with a total length of 400 m Micro-tunnel diameter: 2,800 mm outside diameter Micro-tunnel maximum shaft depth: 13.5 m at Bass River.
Image caption: Image 1: The pipeline passes through farming and agricultural areas as it makes its way to the desalination plant site near Wonthaggi, Victoria; Image 2: Workers prepare to install one of 6,770 pipe sections that make up the 84 km transfer pipeline; Image 3: Pipe laying in progress off the Bass Highway in Lang Lang; Image 4: Laying pipe through the residential areas of Berwick, Victoria; Image 5: Pipe laying in progress off the Bass Highway in Lang Lang.