Replacing ageing water infrastructure across Onehunga requires a carefully planned approach to minimise disruption while delivering a more reliable water network.
Working with Watercare, Kerry Drainage & Civil is undertaking Stage 1 of a major renewal programme, installing approximately 4km of new watermain using directional drilling and open-cut construction.
Much of Onehunga’s existing water network consists of cast iron pipes that are around 100 years old. Decades of internal corrosion have contributed to ongoing discoloured-water issues experienced by some residents. With the problem widespread, replacing isolated sections is no longer enough to address the underlying cause.
Watercare’s staged renewal programme is designed to replace ageing watermains across the Onehunga supply zone, helping improve water quality and support reliable water delivery to local homes and businesses.
A targeted approach to watermain renewal
Stage 1 covers 10 streets: Church Street, Spring Street, Princes Street, Rowe Street, Galway Street, Arthur Street, Jackson Street, Symonds Street, Trafalgar Street and Normans Hill Road.
The works include installing approximately 4km of new watermain through a combination of horizontal directional drilling (HDD), pipe bursting and open-cut methods. The team is also responsible for pressure testing and commissioning the new pipelines, with connections to the existing network facilitated by maintenance contractors.
Maximising trenchless construction
Watercare, Kerry Drainage & Civil is making extensive use of its JT30 directional drill, which has a compact footprint and can install up to 170m of watermain in a single shot. Its size allows the drill to be positioned in berms between driveways, making better use of available corridors and helping reduce excavation and reinstatement.
Where rock conditions require it, the JT30 can be converted to an AT30 configuration using specialist rock-drilling equipment. This flexibility allows the team to adapt its drilling approach to changing ground conditions.
By combining directional drilling with open-cut construction where needed, the project takes a practical, site-specific approach to renewing the network while limiting disruption to the surrounding community.
Investing in Onehunga’s water network
Stage 1 forms part of Watercare’s longer-term investment in replacing ageing water infrastructure across Onehunga. Through specialist trenchless methods and careful construction planning, Watercare, Kerry Drainage & Civil is working to deliver the renewals efficiently while helping prepare the network for the needs of the community into the future.
