On 4 September the Hiwa-i-te Rangi TBM - more than 5m diameter -has broken through into a 69m deep shaft in May Road, Mount Roskill marking the halfway point of her 14.7km journey to central Auckland as it creates the Central Interceptor tunnel, the longest bored tunnel in New Zealand.
The tunnel will run from Māngere Wastewater Treatment Plant to Grey Lynn and will be intersected by two link sewers. The Central Interceptor project is the largest wastewater infrastructure project in New Zealand history and will significantly clean up wet-weather overflows into waterways and the Waitematā Harbour.
The project will be delivered in 2026 as planned despite COVID-19 lockdowns, closed borders, global shipping delays and major weather events.
The Ghella Abergeldie JV as well staff from Jacobs, AECOM, Delve Underground, Watercare and the sub-contractors, are all working hard to deliver this project: around 600 staff working on 16 sites. The TBM tunnelled under the Manukau Harbour, passed 110m under the Hillsborough Ridge and it will reach central Auckland.
The Central Interceptor project has seen a flurry of milestones:
- on December 2022 undersea crossing of the Manukau Harbour from Māngere Bridge to Hillsborough.Undersea tunnels are rare in New Zealand and the 1500m stretch was completed in just 11 weeks.
-on March 2023 it has been completed the first link sewer, to collect flows from Mt Roskill and Blockhouse Bay. Construction has started on a second link sewer, which intersects the main shaft in Wairere Ave, Mt Albert and will be completed in two drives.
- meanwhile, work is progressing well on the Māngere Pump Station, adjacent to the treatment plant. Inflow pipes are being installed and six pumps are being installed, to send flows from the main tunnel to the treatment plant for processing. Section one of the main tunnel (running from May Rd south) and both link sewers are due for commissioning by mid-2024.
The first section running will take pressure off the aging Western Interceptor and the Watercare operations teams will be able to do essential maintenance on the Western Interceptor.
For further information click here and nz/18 for tunnelbuilder archive. Visit https://www.watercare.co.nz/. 36/23.
