Case study

Macquarie River HDD

In 2018, Dunstans Construction Group was awarded a key project by Dubbo Regional Council to install an additional water supply main under the Macquarie River to supply potable water to Dubbo West.

  • Dunstans successfully designed and completed the 300m crossing of the Macquarie River, installing a 400mm HDPE pipe from the Water Treatment Plant to link into the existing pipeline on the opposite side of the river.
  • A 50m section of 30 inch casing was installed by Dunstans air hammer to prevent fluid loss occurring through the shallow gravel formations on the edge and under the river.
  • Due to the restrictive nature of the site, the HDD works was carried out using Dunstans Vermeer D100 x 120 HDD rig and our in-house designed and constructed DCS450 cleaning system.
  • Welding was carried out on the West side of the river on Taronga Western Plains Zoo land. The 312m pipe was strung out on Dunstans pipe rollers to protect the pipe during installation.
  • MetaFLO was utilised to help absorb any remaining moisture in drill cuttings that were removed during fluid recycling in our cleaning system. This innovative and environmentally friendly chemical made the cutting waste easier to handle and dispose of safely.
  • The team was also in charge of tying in the new HDPE pipe to the existing ductile iron pipes on both side of the rive and completing hydrostatic testing and disinfection of the new pipeline prior to commissioning.

Despite the challenging geology under the Macquarie River, the installation of the water main was successfully completed.

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Project quick facts

Client

Dubbo Regional Council

Description

Installation of a new potable water pipeline using HDD under the Macquarie River

Project date

April 2018 – July 2018

Project location

Dubbo, New South Wales

Pipe type

400mm HDPE PN20

Crossing length

300m

Project cost

$650,000

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