Case study

Colac Pipeline – Eel Creek HDD Crossing

In 2011 Dunstans Construction Group, working closely with the Barwon Water Alliance, completed two horizontal directionally drilled crossings in the environmentally fragile Otway Ranges to replace multiple sections of the deteriorating Colac Pipeline.

  • DCG were engaged to drill two separate crossings. The second of which spanned Eel Creek – from approximately 15m above the creek to approximately 50m above the creek. Site set-up was on the corner of a track with a vertical drop to the creek on one side and a cliff on the other.
  • Works were undertaken during winter, when demand on the system was at its lowest. Inclement weather, poor access to the site (within a State Forest) and limited space for our drill hardstand and exit sites, overcome using our extremely mobile and well maintained D100 Drill Spread, requiring only a 5m wide easement set up.
  • The “pose little or no risk” approach to the project saw us work closely with AMC to engineer a suitable drilling fluid that would have the least possible impact on the delicate Otways ecosystem. All aspects of the drilling operation were analysed to ensure best practice in environmental compliance.
  • We completed the design, engineering and construction of the new pipeline and successfully completed the pipe installation on time using our Vermeer D100x120 Drill Spread.

This was the first project completed by the Vermeer D100 Drill Spread. Dunstans delivered this project on time, budget and with no time lost due to injury – satisfying all safety and quality standards.

Project quick facts


Barwon Water Alliance


Installation of 500mm HDPE pipe in the Otways by HDD

Project date

May – October 2011

Project location

Eel Creek, Otways Ranges, Victoria

Pipe type

500mm OD HDPE pipe

Crossing length


Project cost