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Customer: Auckland Council Healthy Waters Contract: Construct only Location: Greville Road, Pinehill, Auckland   |
Fast Facts:
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We had an experienced tunnelling team ready to go, so we took on emergency work for Auckland Council Healthy Waters after major Auckland floods.
The Corban Reserve Stormwater Upgrade for Healthy Waters was still underway at the time of the flooding. Our team had just finished the 713 m long tunnelling drive at that job, so it was good timing and an easy transfer of skills, experience, materials, and equipment from the worksite out west to Greville Road for the Stormwater Culvert Upgrade.
The existing Greville Road culvert, a 1950 mm diameter ARMCO pipe, ran from near the old Rosedale Landfill beneath Greville Road - a key arterial that connects to the Northern Motorway, and the Albany Expressway - to an inlet on the northern side of the road.
The initial plan was to excavate and remove the collapsed culvert and replace it with a temporary shaft. During the value engineering process, the team identified an opportunity to save time, money and avoid rework later in the programme. As a result, the shaft was designed and constructed to accommodate a manhole and a permanent inlet rather than a temporary solution.
Another innovation on the project was the team's development of low-carbon concrete jacking pipes. With Healthy Waters and supplier Hynds, the team designed low-carbon pipes suitable for tunnelling, achieving a 16% reduction in carbon emissions, saving 62 tonnes of CO2e. To put the figure in context, a car driving the length of New Zealand 122 times would produce the same carbon emissions.
Work to unblock the culvert began in March 2023. The team began excavating the main shaft for the new pipeline in early 2024, and the project was completed in early 2025.
The project team identified sustainable construction solutions such as:
- using low carbon pipes saving 62 tonnes of CO2e
- reducing the amount of waste that went to landfill by 95%
- reusing materials and equipment, including the TBM from the Corban Reserve Project
- recycling 500 tonnes of aggregate as backfill in the shafts
- 1,540 tonnes of aggregate were reused by the Council's Parks Team
- recycling 265 tonnes of concrete waste
- and 19.8 tonnes of reinforced concrete pipe
- using solar-powered monitoring equipment
- repurposing 59 concrete interblocs
- 650,000 litres of stormwater were recycled, avoiding 366 kgCO2e
- 28% of the contract value was spent with 37 local businesses
- and $530,000 was spent with Amotai-approved businesses and social enterprises.
