CDS New Zealand Ltd delivered the First Avenue Stormwater Renewal project in two stages for Auckland Council, combining emergency civil works with a highly constrained trenchless pipe replacement beneath established residential properties.
The first stage was undertaken as an emergency response in September 2024 and involved the installation of a new 1,800 mm diameter stormwater manhole within First Avenue. This new structure was designed to facilitate the later trenchless replacement works and provide sufficient working space for the restrained pipe installation.
The second stage was completed between March and May 2025 and involved the replacement of approximately 62 m of 300 mm diameter stormwater pipe using pipe bursting / pipe reaming techniques. The replacement pipeline comprised 300 mm PVC RESTRAIN pipe supplied in 1 m lengths, with each section assembled from within the new 1,800 mm diameter manhole as the pipe installation progressed.
Due to the restricted urban environment, the CDS drill rig was established within private property approximately 40 m back from an existing 6 m deep stormwater manhole in Second Avenue. CDS drilled through this manhole to enter the existing stormwater line, before advancing the drill rods along the existing alignment toward the newly constructed manhole in First Avenue.
The failed pipeline was then burst / reamed between the new manhole and an intermediate pit located within private property.
Following completion of the trenchless works, CDS constructed the required downstream manhole works and redirected existing private drainage connections into the new stormwater system.
A key project risk was that the 62 m pipeline alignment passed directly beneath two existing residential properties. Strict survey monitoring was undertaken throughout the construction period to identify any movement associated with the pipe reaming works. No movement attributable to the trenchless installation was recorded.
The project required close coordination with Auckland Council and affected residents throughout both stages of construction. CDS worked directly with property owners to manage access, communicate construction activities and minimise disruption and concern associated with working beneath established homes.
The First Avenue project demonstrates CDS’s trusted and proven ability to apply HDD and trenchless technology outside traditional pipeline installation methods. Through careful risk management, specialist construction methodology and strong stakeholder engagement, CDS successfully delivered a complex stormwater renewal within a highly constrained residential environment.
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