In April 2008, Wannon Water released a detailed route for the pipeline. The 53 kilometre, 375 mm diameter, ductile iron cement-lined pipeline is to be located largely on private property between Rocklands Reservoir, located in the Grampians, and the existing pipeline on the Dunkeld-Cavendish Road, southeast of Cavendish. The pipeline will then connect to the existing Grampians Headworks Pipeline, transferring up to two billion litres of water each year from the reservoir to Hamilton’s water supply system.

Wannon Water awarded the construction contract to Padbury Amber Civil Contractors, while the contract for the supply of the pipes and fittings went to Tyco Water. Construction began in April this year, with 15 per cent of the pipelaying process complete to date.

Challenges

It became apparent to Wannon Water that challenges would be faced during the construction of the pipeline, which traverses the Claude Austin State Forest, and sensitive environmental areas including several waterways.

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The Victorian Department of Sustainability and Environment, as well as independent consultants have undertaken stringent environmental monitoring in order to minimise any negative impacts during construction of the pipeline.

In order to facilitate these environmental measures, Wannon Water General Manager Assets Brian Jenkins says that “Trenchless Technology is being used in the construction of the pipeline in part to avoid conflict with environmentally sensitive flora and fauna.

“A difficult challenge has been to find a route which minimises environmental impacts. The solution to the preservation of the most important environmental areas has been to use Trenchless Technology.”

Using Trenchless Technology

It was originally estimated that approximately 900 metres of boring would be required to pass under sensitive flora, a rock outcrop, road reserves, a significant trees, a structure and a river.

Horizontal directional drilling had been planned for the project, with up to 29 bores thought necessary to carry the pipeline beneath waterways and other sensitive areas.

However, Mr Jenkins says that due to encountering “additional environmental issues”, Wannon Water has had to expand the role of HDD in the construction process.

“Additional bores are now planned and are being carried out, which is resulting in approximately 50 per cent more bores being required.”

Padbury Amber Civil Contractors has sub-contracted SJM Directional Drilling to supplement its own boring crew.

The HDD teams will use the Ditch Witch JT-3020, as well as the Vermeer D24-X411 in their trenchless operations.

Using Trenchless Technology means that there will be no requirement for road closures, thus minimising any inconvenience to surrounding landowners during the construction phase of the project.

Currently, eight kilometres of pipe has been laid across the Wannon River and in the vicinity of Rigby and Yarramyljup Roads, and more is expected to be laid under the Pendyk Creek. Thirty-six kilometres of pipe has now been delivered along the pipeline route. Work is expected to continue through the Claude Austin State Forest and north of Luhrs Road.

To date, construction of the pipeline is ahead of schedule. On its completion, the Hamilton to Grampians Pipeline will have a life expectancy of 100 years. The date for completion is now expected in early 2010.