Work underway on Auckland’s next major wastewater tunnel

Auckland’s next major wastewater tunnel project has reached a significant milestone, with a 56.5 metre tower crane now installed to help construct infrastructure that will significantly reduce wet-weather overflows into the Waitematā Harbour.

The crane has been installed for Watercare’s $260 million Herne Bay Collector project, which will connect to the Central Interceptor and capture wet-weather overflows for treatment rather than allowing them to enter the environment.

Delivered by Italian tunnelling specialist Ghella, the 1.7 kilometre-long, 2.1 metre-diameter wastewater tunnel will play a key role in improving water quality in the Waitematā Harbour and surrounding coastal areas.

Waitematā Local Board Chair Alexandra Bonham says the project represents a major step forward for the area's environmental health.

“The Herne Bay Collector will deliver significant environmental benefits, helping to reduce wet-weather overflows and improve the health of the Waitematā Harbour.

“The work in Herne Bay will cause some disruption, and we are grateful for the community’s patience. We are all looking forward to the long-term benefits this infrastructure will provide, including improved water quality and cleaner, more swimmable beaches for the community.”

Herne Bay’s combined wastewater and stormwater network was historically designed to overflow during heavy rainfall events to help protect homes and businesses from flooding.

The Herne Bay Collector will capture these overflows and divert them to the Central Interceptor instead of the harbour.

The project includes seven main shafts, three intermediate shafts and a seven-storey underground control chamber beneath Point Erin Park.

The chamber will connect the Herne Bay Collector to the northern end of the Central Interceptor and help direct wastewater flows for treatment during wet weather.

Watercare Waitematā Water Quality Improvement programme director Morris Taylor says the newly installed tower crane will be critical to delivering the project.

“The control chamber will act as a gateway between the Herne Bay Collector and the Central Interceptor, helping direct wastewater and stormwater flows for treatment instead of allowing them to overflow into the harbour.

“The tower crane gives us the lifting capability we need to construct this infrastructure safely and efficiently. It will be used to lower reinforcing steel, formwork and other construction materials into the excavation as the chamber is built from the bottom up.

“It will also help install major pipes and precast concrete structures weighing up to 24 tonnes, reducing our reliance on temporary mobile cranes while improving productivity and accessibility, reducing noise and vibration, and enhancing safety on site.”

Taylor says the crane installation marks an important milestone as construction gathers pace.

“With the Central Interceptor now in service, the Herne Bay Collector is the next major step in transforming how Auckland manages wastewater during wet weather.

“By combining world-class tunnelling expertise, modern construction methods and long-term planning, we’re delivering infrastructure that will provide environmental benefits for decades to come.

“We thank the community for their patience. We know projects of this scale can affect day-to-day life, and we’re committed to keeping the community informed and minimising disruption wherever possible.

“The result will be lasting improvements to the health of the Waitematā Harbour and a stronger wastewater network for future generations.”