Watercare's Hiwi-i-te-Rangi Tunnel Boring Machine has reached the halfway mark of its 14.7-kilometer journey to central Auckland as it excavates the Central Interceptor tunnel.
Video / Watercare Services Ltd
As it digs the Central Interceptor tunnel, watercare’s Hiwi-i-te-Rangi gigantic Tunnel Boring Machine today reached the halfway point of her 14.7-kilometre voyage to central Auckland.
It achieved this by breaking through into a shaft at May Rd, Mount Roskill.
Wet weather overflows into waterways and the Waitemata Harbour will be greatly cleaned up by the Central Interceptor project, the greatest wastewater infrastructure project in New Zealand history.
Between the Mangere Wastewater Treatment Plant and Grey Lynn, the tunnel will be crossed by two link sewers.
The gathering construction teams cheered enthusiastically as the over-five-meter-diameter cutter head broke through a 69-meter-deep shaft wall, Watercare Central Interceptor executive programme director, Shayne Cunis said.
Watercare Central Interceptor staff celebrate the Tunnel Boring machine Hiwi-te-Rangi breakthrough at May Road, Mount Roskill
Cunis said that despite substantial obstacles, the breakthrough represents a crucial turning point in the project.
“We all deserve to savour this moment,” Cunis said.
“We’re on track to deliver this project in 2026 as planned despite everything that has been thrown at us — Covid-19 lockdowns, closed borders, global shipping delays and major weather events. But most importantly, the project is being delivered safely.”
The most exciting part of the journey so far, according to Cunis, was crossing the Manukau Harbour from Mangere Bridge to Hillsborough in 2022. In New Zealand, there aren’t many underwater tunnels, and the 1500-meter section was built in under 11 weeks.
There have been numerous Central Interceptor project milestones. Following the December 2022 undersea bridge, the first link sewer, which would collect flows from Mount Roskill and Blockhouse Bay, was finished in March this year. A second link sewer that will be built in two drives and intersect the main shaft at Wairere Avenue, Mount Albert, has begun construction.
Watercare Central Interceptor information graphic showing the progress made by the Tunnel Boring Machine
Cunis paid tribute to Ghella Abergeldie JV construction partners, as well staff from Jacobs, AECOM, Delve Underground, Watercare and the sub-contractors, who have “all worked hard to deliver this project in the best way”.
Ghella Abergeldie JV project director Francesco Saibene also praised his tunnelling team.
“We have worked very hard to achieve this milestone. The Central Interceptor will be the longest bored tunnel in New Zealand and reaching the halfway mark is a moment for us all to celebrate,” Saibene said.
The nearby Mangere Pump Station project is making good development in the meantime. Six pumps and inflow pipes are being erected in order to transfer flows from the main tunnel to the treatment facility for processing.
Auckland’s Central Interceptor wastewater tunnel.
Both the connection sewers and Section 1 of the main tunnel, which extends from May Rd south, are scheduled to be completed by the middle of 2024.
According to Cunis, launching the first segment will relieve pressure on the Western Interceptor, which is getting older.
“Resilience has always been a key driver for the project, along with providing for future growth and environmental benefits,” Cunis said.
“Once section one goes live, our Watercare operations teams will be able to do essential maintenance on the Western Interceptor.”
