After ten months being constructed in a German factory and a month travelling the high seas, our Central Interceptor Tunnel Boring Machine (TBM), named Hiwa-i-te-Rangi, has safely arrived on our shores. The machine, which was dismantled before shipping, will begin digging a 14.7km wastewater tunnel from Grey Lynn to Māngere in early 2021.

Early this morning (Monday), the first of 27 trucks began transporting parts of the TBM from Ports of Auckland to the Māngere Wastewater Treatment Plant - the launch site for the $1.2 billion project. The remaining pieces will be transported tomorrow (Tuesday), with oversize loads being moved overnight.

Mayor Phil Goff, who will officially launch the five-year tunnelling operation on 14 December, says the Central Interceptor will make a real difference to the health of the beaches and waterways in central Auckland.

“The Central Interceptor is the largest wastewater infrastructure project ever undertaken in New Zealand. Once complete, this $1.2 billion project will dramatically improve the health of our harbours, beaches, and streams by reducing wet-weather overflows by up to 80 per cent.

“It is a huge investment, but it means we can leave a legacy of clean, safe, healthy beaches for our children and grandchildren to enjoy.”

Watercare Central Interceptor executive programme director Shayne Cunis says, “Despite the challenges we have faced this year with COVID-19, we have made significant progress on the project, and the arrival of the TBM sets us up for another great year in 2021.”

Several Central Interceptor construction sites are currently in progress. Works at Māngere and May Road (Mt Roskill) shaft sites are the most advanced. At Māngere, excavation of the 38-metre-deep main shaft (wet well) and 32-metre deep inlet shaft are complete, with the concrete base slab at the bottom of both shafts now being installed. Further sites along the tunnel route will commence in 2021.

Due to the size of the TBM – once pieced together it will be 190 metres in length – it will not be fully assembled by our contractor Ghella Abergeldie JV and Herrenknecht until it is launched underground in early 2021.

Project videos

• Central Interceptor Tunnel Boring Machine (TBM) is complete: https://youtu.be/dTjdD5wOLlE
• Tunnel Boring Machine receives Matariki star name: https://youtu.be/3PPWka0F1Sk

Information

• Between 2019 and 2028, we’re investing $3.6 billion on expanding and upgrading our wastewater infrastructure across Auckland so that we can cater for our growing population. Then from 2028, we will invest an additional $2.4 billion over the next 10 years.

How the Central Interceptor will benefit Auckland:

Reduce overflows

When it rains the central wastewater network overflows to local waterways and the Waitematā Harbour at more than 100 locations and to the north-eastern Manukau Harbour at 14 locations.

The Central Interceptor is an integral part of our long-term strategy to effectively manage wastewater within Auckland. While we’re building the tunnel, we will also be working on other projects in the western isthmus, such as separating the stormwater and wastewater pipes. Together, the Central Interceptor and our western isthmus strategy will reduce overflows in the area by up to 80 per cent.

Reduce environmental risks

The existing wastewater pipeline that passes under the Manukau Harbour was built in 1964. This pipe is now reaching the end of its operational life. If the pipe is damaged or fails, untreated wastewater could be discharged into the Manukau Harbour.

When the Central Interceptor is complete it will help keep the Manukau Harbour clean. It will also significantly reduce the largest existing combined wet-weather overflows in Auckland, located at Lyon Avenue in Mt Albert and Haverstock Road in Sandringham.

Increase network flexibility

The Central Interceptor will help us provide additional capacity in central Auckland and free up capacity in the east and west of the city. This means we can take critical infrastructure out of service for maintenance without impacting our services to you.

Help a growing city

Auckland ‘s population is growing significantly. Over the next 30 years, we’ll need room for another one million people. The Central Interceptor is critical to providing additional wastewater capacity for our expanding population and connection of future wastewater projects.

Connecting to the western end of the Ōrākei Wastewater Interceptor, the Central Interceptor will provide a more direct route to the Māngere Wastewater Treatment Plant for much of central Auckland’s wastewater flows. This will allow greater capacity for growth in other parts of the network. The Northern Interceptor, which we started to build in 2018, will divert some of the northern wastewater flows to Rosedale Wastewater Treatment Plant, freeing up more capacity in the southern network to allow for future growth

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