The confirmation of the extension from Grey Lynn to Point Erin in Herne Bay follows agreement on Local Water Done Well between Auckland mayor Wayne Brown and local government minister Simeon Brown earlier this month.
The 4.5m diameter Central Interceptor tunnel in New Zealand’s largest city runs from Māngere Wastewater Treatment Plant across the Manukau Harbour to central Auckland, with two new link sewers collecting flows from west Auckland. It is the largest wastewater infrastructure project in New Zealand’s history and will significantly reduce wet weather overflows into waterways as well as the Waitematā Harbour.
The project will also improve the resilience of the wastewater network and allow for population growth in the city.
TBM Hiwa-i-te-Rangi has excavated more than 11km since leaving Māngere in August 2021 and is approximately 60m under Mt Albert, heading towards Western Springs.
Mayor Brown said it would be the first of many projects to benefit Aucklanders following the Local Water Done Well agreement.
“The deal was about fixing Auckland’s water infrastructure. We avoided major hikes in water charges, while enabling major investment in water infrastructure that will last generations and make Auckland a better place to live,” he said.
The Central Interceptor project is on track to be operational up to Grey Lynn in 2026. The Point Erin extension will be commissioned in 2028 when it connects to an upgraded Herne Bay Trunk Sewer.
Construction of the Central Interceptor project has passed the halfway mark, with more than 600 staff working on 16 sites across Auckland. It involves more than 16km of tunnelling, 4km of micro-tunnelling, the construction of 17 shafts and major new infrastructure including a new pump station at the Māngere site to send flows from the main tunnel to the treatment plant for processing. Crews will also shortly begin connecting the aging Western Interceptor to the Central Interceptor.
The project is being delivered by Ghella Abergeldie JV. The southern section of the tunnel from May Rd, Mt Roskill south and one link sewer is due to go live by the end of the year.
