Yarra Valley Water’s Doreen to Diamond Creek Sewerage Project involves constructing a new 10km-long section of sewer pipe, and 17 new sewer maintenance holes, within parkland and road reserves in the Doreen, Yarrambat and Diamond Creek areas.

The new sewerage infrastructure will ensure the reliability of the sewerage system, cater for growth in Melbourne’s northern suburbs, and reduce the likelihood of sewage spilling into the environment during heavy rain events.

Construction started in March 2019, and is scheduled to be completed in mid-2021, subject to weather and ground conditions. The project is being delivered in five sections and includes sites in environmentally sensitive areas, such as Plenty Gorge Parklands.

To reduce the impact on the environment, and to avoid disturbing areas where Aboriginal artefacts have been discovered, most of the new pipe is being constructed by using trenchless technology.

Pezzimenti Trenchless was engaged by Yarra Valley Water contractor, MFJ Constructions, to install just over 900m of 718mm OD GRP pipe using its method of laser-guided microtunnelling. The depths ranged from 5m to 12m deep, with bores that varied in length from 30m up to 110m.

Joe Pezzimenti, Managing Director of Pezzimenti Trenchless, said, “Our method was used due to the depths required, location (main roads which needed a small set-up footprint) and the accuracy required to achieve flat grades of one in 400.

“Further trenchless methods were used on the project where the depths were shallower and the grade was not as critical.”

One of the biggest challenges was the hard siltstone ground conditions – with a compressive strength of up to 40MPa – which was made more difficult by the depth and tight launch locations.

COVID-19 restrictions also impacted the size of the crew, but this did not prevent Pezzimenti Trenchless from getting the job done.

Pezzimenti Trenchless completed the works in September 2020, achieving a great result that benefitted from a collaborative approach with MFJ Constructions and Yarra Valley Water.

This partner content is brought to you by Pezzimenti Trenchless. For more information, visit

Charlotte Pordage is Editor of Utility magazine, a position she has held since November 2018. She joined the team as an Associate Editor in October 2017, after sharpening her writing and editing skills across a range of print and digital publications. Charlotte graduated from Royal Holloway, University of London, in 2011 with joint honours in English and Latin. When she's not putting together Australia's only dedicated utility magazine, she can usually be found riding her horse or curled up with a good book.

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