In the ever-expanding western suburbs of Melbourne, Melbourne Water and contractor John Holland have recently commenced construction on a project to increase drinking water supply for one of Melbourne’s fastest growing regions.
The project involves the construction of over 17 km of new pipeline that will help secure a reliable water supply for Melbourne’s outer west, Australia’s third-fastest growing region, and meet the increased demand for clean drinking water in these suburbs.
The Water for a Growing West (WGW) project was conceived to supplement water supply to the Cowies Hill Reservoir, located near Tarneit, Victoria, through construction of a 17.4 km watermain from the St Albans Reservoir in Melbourne’s west.

Construction details
Following an open market tender process in August and September 2014, the lump sum construction contract for the St Albans to Werribee water pipeline was awarded to John Holland on 3 October 2014.
The watermain will consist of 15.2 km of larger diameter pipeline – 1,150 mm concrete lined mild steel and 1,200 mm fibre reinforced plastic (FRP) – and 2.2 km of 750 mm diameter concrete lined mild steel. The majority of the watermain is located within existing and future road reserves and high voltage electricity transmission easements.
Planning for a water future
City West Water (CWW) is the area’s water retailer, and Melbourne Water is responsible for supplying the utility with its potable water requirements.
Project feasibility studies commenced in mid-2010 and incorporated extensive demand modelling. Analyses undertaken in partnership with CWW revealed that an upgrade to the network would prevent demand outstripping supply, and so the project was conceived.
Melbourne Water achieved extensive material cost savings by working closely with CWW to analyse future integrated water management opportunities. Analyses showed the uptake of recycled water schemes in the area would reduce potable water demand, and in turn reduce the cost of the project by enabling the size of the pipe to be downsized.
Dealing with project complexities
The WGW project spans over three Council jurisdictions: Brimbank, Melton and Wyndham. A Planning Scheme Amendment (PSA) was pursued and approved for the project, which required extensive consultation with councils and state departments to ensure each stakeholder’s considerations were included in the WGW Project requirements.
With a mandate to have water supply up and running by November 2015, Melbourne Water had to work hard to meet stakeholder requirements and balance relationships with a number of Councils.
Due to the growth of the outer western suburbs, planning or construction of other infrastructure upgrades is also taking place. Route selection, coordination of surveys and land tenure was undertaken in conjunction with road upgrades (in conjunction with VicRoads and councils), the Regional Rail Link, planned transport terminals and other essential services infrastructure including water, sewerage, electricity and gas.
A community affair
Ongoing liaison with stakeholders for the project has occurred since feasibility studies commenced in 2010. City West Water, as the area’s retail water authority, has been a key stakeholder since commencement.
Mr Clark said, “A high level of consultation and coordination with Councils, State Departments and other stakeholders was required through the planning phases of the project, and for the purpose of obtaining the PSA.”
Environmental and cultural considerations
The WGW Project will cross a wide variety of terrain, including urban, rural and farmland, each with its own complexities. Melbourne Water put strict environmental and heritage controls and management plans in place due to the location of the project.
Located in grasslands that are home to several threatened fauna species, including the Golden Sun Moth, Growling Grass Frog and Striped Legless Lizard, Melbourne Water took extensive measures to ensure the delicate environmental and cultural surrounds weren’t negatively impacted upon.
The grasslands also contain the Spiny Rice Flower, a threatened flora species. Management plans were developed to avoid, minimise or mitigate impacts to the threatened flora and fauna species through construction.
Cultural considerations particularly came to the fore when planning to cross Kororoit Creek, an area of known sensitivity that Melbourne Water Senior Project Manager Peter Clark described as “an environmental and cultural hotspot.” Cultural Heritage surveys were carried out and a Cultural Heritage Management Plan was developed and approved for the project, and an archaeological salvage in proximity to Kororoit Creek will be completed prior to construction.
Dry stone walls are located along the alignment, where their former (and in some cases current) use was for holding livestock. These dry stone walls are heritage-listed, so a Dry Stone Wall Management Plan has been developed for the protection and reinstatement of the walls and fences.
Safety techniques
“Safety is our highest priority at Melbourne Water, as demonstrated through our ‘zero harm’ philosophy,” said Mr Clark.
Melbourne Water has requested a comprehensive Safety Management Plan from contractor John Holland, which will be adhered to throughout the construction phase of the project.
Challenges and solutions
“The geology of the area and existing infrastructure provided the key engineering challenges for the project,” explained Mr Clark.
The WGW Project area is predominantly located within basalt plains, and large basalt boulders or ‘floaters’ are scattered along the watermain alignment.
“Where drilling is required to cross existing infrastructure, the drilling will be carried out in the deeper consistent rock rather than the variable ground conditions,” said Mr Clark.
Investigation took place into three possible crossing methods of Kororoit Creek, including:
- Trenchless- HDD or other drilling method;
- Pipe bridge; and
- Conventional trench.
Conventional trenching methods have been adopted as much as possible (including for the crossing of Kororoit Creek) due to the geotechnical conditions.
The majority of the alignment is within a high voltage electricity transmission line easement; due to the induced voltage issues and complex corrosion control equipment associated with the use of welded steel pipe near high voltage lines, FRP with rubber joints has been adopted instead.
Other infrastructure crossings include major transport arterials such as Ballarat Road, Robinsons Road and multiple crossings of the Regional Rail Link.
“Through forward planning of the project, Melbourne Water was able to have sleeves installed for two of the three rail crossings through the construction of the Regional Rail Link. As a result, the need for trenchless crossings through construction of the WGW was removed,” said Mr Clark.
Innovation
Innovations through the design and planning of the WGW Project include:
- Collaboration between current and planned infrastructure owners in selection of the best route and construction methods;
- Use of alternate materials when traversing HV power lines; and
- Conventional trench was determined to be the safest (due to the HV overhead) and also cause the least environmental or cultural damage to the sensitive area.
Next steps
The Melbourne Water and John Holland project team mobilised to the project site offices in early December 2014.
At the time of going to print, some preliminary activities had been undertaken, including surveying, temporary fencing and pipe stringing, while construction activities, including clear and grade, trenching, pipe laying and burying will commence early in the new year.
Mr Clark said the commencement of construction is an important milestone for the project that will ultimately improve the reliability of water supplies in Melbourne’s rapidly developing Wyndham region.
Meanwhile, commissioning remains on schedule for mid to late 2015.
This article was featured in the February 2015 edition of The Australian Pipeliner.
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