Northern Interceptor

Catering for Auckland's future growth

The amount of wastewater being collected and treated has increased significantly as Auckland’s north-west has expanded.

To cater for this future growth in Auckland and free up the Māngere Wastewater Treatment Plant, the $108 million Northern Interceptor wastewater pipeline will redirect wastewater flows from Massey North, Whenuapai, Hobsonville, Kumeu, Huapai and Riverhead to the Rosedale Wastewater Treatment Plant, located on Auckland’s North Shore.
 
The project which involves around seven kilometres of wastewater pipe and four kilometres of watermain, with a causeway widening and two to three pipe bridges, will start in multiple areas between Hobsonville and Rosedale.

Construction started in January 2019 and is expected to be completed in 2021. Phase one of the project is combined with the watermain improvement works across the upper Waitematā Harbour and expected to be completed by 2020.

Challenges include working in a busy urban environment and the slinging of a pipe under the existing Greenhithe Bridge, while traffic flows over the top of it.

The Northern Interceptor will contribute significantly to the protection of public health, environmental quality, and the social, cultural and economic well-being of the area.

By the numbers:

• Two-year project located on Auckland’s North Shore.
• Seven kilometres of wastewater pipe and four kilometres of watermain.
• One causeway widening on Greenhithe Bridge.
• Two pipe jack tunnels under State Highway 18.
• Three horizontal directional drill shots (twin 560 interior diameter) up to 900 metres.
• Two to three pipe bridges.
• One NH2 watermain pipe slung/fixed under the existing Greenhithe Bridge.