Digging Deep in the Waitakere Ranges

Digging Deep to complete NZ’s toughest HDD project

A new pipeline was needed to replace a failing cast iron watermain laid during World War Two, which traversed some of the most rugged topography and dense bush imaginable.

The existing cast iron watermain mostly mimicked the topography of the route and was left exposed in many locations. Ground movement and erosion led to high ongoing maintenance of the cast iron pipeline constructed in 3m long sections.

The new pipeline that Universal Underground would be installing was a siphon with a height difference between ends of 40m and a low point 80m below the high point. The pipeline would cross under five streams, pass beneath bluffs by up to 40m deep, intersect conglomerate gravel beds and pass through sections of faulted ground.

On completion the pipeline would offer a smooth straight alignment with an increased capacity, improved efficiency and near nil ongoing maintenance issues.

To read how this project and it’s many challenges were undertaken and overcome click on the link to the brochure below.

Waitakere Brochure