Tunnelling has begun under Auckland’s CBD as part of the Midtown Wastewater Diversion project.
A micro TBM is digging a 600m tunnel under Queen Street in New Zealand’s largest city to lay a new wastewater pipe.
Watercare’s acting chief programme delivery officer, David White, said the new 1.2m diameter pipe would connect to the Ōrākei Main Sewer and capture wastewater flows from the city centre.
“The start of tunnelling is an important milestone in our NZ$115m (€58.5m) wastewater upgrade for the city centre. This project will reduce wet weather overflows into the Waitematā Harbour, improve the resilience of our network and allow for growth,” he said.
“We began construction in October last year and it’s good to see tunnelling getting under way. We chose this method of construction as opposed to open trenching to minimise disruption to pedestrians and businesses.”
The m-TBM was launched from a shaft at the junction of Queen Street and Mayoral Drive. Tunnelling will be done in two drives. The TBM will bore through the ground at depths of 15m to a shaft at the corner of Wellesley Street East and after a cutterhead inspection, it will continue boring to reach the final shaft at the junction of Victoria Street East towards the end of the year.
The m-TBM will employ pipe-jacking to lay the glass-reinforced plastic pipe in 6m-long sections.
Tunnelling is part of the first stage of the Midtown Wastewater Diversion project. Stage two of works is in design and will involve laying new wastewater pipes from Vincent Street to Greys Avenue carpark. The work is due to be completed in 2027.
The project is part of Watercare’s NZ$13.8bn (€7.06bn) infrastructure investment programme being delivered over the next decade to enable new housing, improve the reliability of services and protect the environment. It is part of the Auckland Council group’s midtown regeneration programme which is transforming the streets, spaces and underground infrastructure ready for the City Rail Link opening.
