Funding has been confirmed to extend the Central Interceptor wastewater tunnel by more than 1 km from Grey Lynn to Point Erin, Herne Bay. This will reduce wet weather overflows and significantly improve water quality in Herne Bay and St Marys Bay waterways and beaches. The TBM Hiwa-i-te-Rangi will continue from Tawariki St, Grey Lynn, and will bore at depths of between 17m and 60m to arrive 30m below the surface at Point Erin Park.
The confirmation follows agreement on Local Water Done Well between Auckland Mayor Wayne Brown and Local Government Minister Simeon Brown earlier this month.
The funding for the tunnel extension will be shared with Healthy Waters, as referenced by Auckland Council’s recent commitment to funding water infrastructure in their Long-term Plan (LTP). The governing body (made up of the Mayor and 20 ward councillors) is expected to sign off the LTP in coming weeks.
Construction of the Central Interceptor project has passed the halfway mark and it is on track for completion in 2026. By then, it will be fully operational up to Grey Lynn. The Point Erin extension will be commissioned in 2028 when it connects to an upgraded Herne Bay Trunk Sewer: beaches in St Marys Bay and Herne Bay will be significantly cleaner for generations to come.
The project involves more than 16 km of tunnelling, 4 km 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. The 4.5 m diameter Central Interceptor tunnel runs from Māngere Wastewater Treatment Plant across the Manukau Harbour to central Auckland, with two new link sewers collecting flows from west Auckland.
Crews will also shortly begin connecting the aging Western Interceptor to the Central Interceptor, to increase resiliency throughout the wastewater network.
The project is being delivered by construction partners Ghella Abergeldie JV. The southern section of the tunnel from May Rd, Mt Roskill south plus one link sewer is due to go live by the end of the year.
For further information click here and nz/18 for the tunnelbuilder archive. Visit https://www.watercare.co.nz/ and https://www.ghella.com. 23/24.
