What began as a four-week enabling works package grew into an 18-month project.
Kerry Drainage & Civil worked alongside Brian Perry Civil and Watercare to deliver critical underground infrastructure for the Papakura Water Treatment Plant, including water supply pipelines, treated water distribution and drainage systems.
The Papakura Water Treatment Plant project helped reconnect, treat and distribute a valuable water source during Auckland’s severe drought in 2020. Kerry Drainage & Civil initially engaged directly with Watercare to complete enabling civil works ahead of the wider treatment plant construction.
Following the successful delivery of this initial package, Kerry Drainage & Civil was engaged by main contractor Brian Perry Civil to undertake further underground infrastructure works, working closely with both the contractor and Watercare as the project developed.
Adapting as the project evolved
The scope expanded significantly from the original four-week programme. Kerry Drainage & Civil’s work included installing HDPE raw water supply pipelines, CLS treated water distribution pipelines, and stormwater and effluent drainage systems.
With the project timeline accelerated and not all work packages able to be fully priced in advance, Kerry Drainage & Civil adopted a transparent approach to cost management. Labour and plant hours were recorded daily and reviewed weekly with the client, while external invoices were made available for review.
Where practical, individual sections of work were identified and priced separately, helping the team identify efficiencies and maintain visibility of costs as the programme evolved.
A trenchless solution beneath an existing reservoir
During construction, the team identified that an existing reservoir outlet was in poor condition and too small to accommodate the proposed flows. Rather than undertaking conventional excavation beneath the existing reservoir, Kerry Drainage & Civil worked with the design team to develop an alternative trenchless solution.
A 1280mm GRP carrier pipe was jacked beneath the reservoir, creating a route for a prefabricated DN600 CLS outlet pipe, installed by Kerry Drainage & Civil in collaboration with GFS.
This solution addressed the outlet requirements while avoiding the need for open excavation directly beneath the existing reservoir.
Finding practical solutions on site
The project also presented challenges with the availability of suitable shoring equipment for a section of treated water pipeline and valve chambers. To overcome this constraint, the team revised its construction methodology, opening up the full section and battering the excavation sides instead of relying on the limited shoring resources.
These practical adjustments helped Kerry Drainage & Civil respond to changing site requirements while continuing to deliver the wider infrastructure works.
Delivering critical water infrastructure
The project demonstrated Kerry Drainage & Civil’s ability to scale up from a small enabling works package to a substantial construction programme, combining collaborative delivery, transparent cost management and practical engineering solutions.
The underground infrastructure formed part of the wider Papakura Water Treatment Plant project, helping support the treatment and distribution of an important water source during a challenging period for Auckland’s water supply.
