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Central Interceptor: The largest ever wastewater project in Aotearoa

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 Central Interceptor.

Everybody wants to enjoy their local rivers, beaches and estuaries. But overflowing water systems during large rain events can stop this from happening in Tāmaki Makaurau Auckland, our biggest city. It's underground wastewater system is old, the city’s population is growing, and when it rains hard the system cannot handle all the stormwater as well as all the wastewater. This can impact parts of the environment and be a risk to people's health. 

Enter the Central Interceptor (CI), the largest ever wastewater tunnel in Aotearoa. It has this name because the tunnel will go under central Tāmaki Makaurau Auckland and pick up, or ‘intercept’ the mix of wastewater and stormwater before it can go into our waterways. 

The CI will be nearly 15 kilometres long and 4.5m high (that’s as tall as a giraffe): it will be able to hold 200 million litres of water, which is the same as about 700 school swimming pools. Think of a litre of milk in your fridge: there are 300,000 of these in just one school pool! 

The CI will lie between 15 and 110 metres underground. A tunnel boring machine (TBM) will dig the tunnel and lay segments of the tunnel wall as it goes.

Travel online Tāmaki Makaurau Auckland to:

  • get behind the scenes of the largest ever wastewater project in Aotearoa and connect with people involved in the construction process
  • learn how wastewater and stormwater is managed and why this is important
  • explore the value of iwi and community consultation, and involvement
  • discover how valuing sustainability on this project will benefit the environment, city, and people who live there
  • inquire into how you can act to improve the quality of water around you.


All the field trip material including video, a Google Earth for Web tour, background support and online quizzes will be available from the beginning of Term 3 2022.

Enrol in this trip to receive supporting communication and resources from the LEARNZ team, and connect with field trip experts in our live web conferences. 

From a previous LEARNZ online field trip:


United Nations Sustainable Development Goals.

United Nations SDG 9This trip reflects the United Nations Sustainable Development Goals (SDGs), especially Goal 9: Industries, Innovation and Infrastructure: Build resilient infrastructure, promote sustainable industrialization and foster innovation.



LEARNZ online field trips support students and teachers to access the inaccessible, digitally transporting them to remote locations all over Aotearoa, Antarctica and beyond. Our trips are FREE to use!