Sector
Building & Infrastructure
Sub-Sector
Watercare
Looking for
Contractor to bore and then construct the tunnel
Summary
A new tunnel needs to be built to connect the Orākei main and Grey Lynn sewers which are currently at capacity during rain events. This new tunnel will reduce wastewater overflows in the Grey Lynn area, resulting in better water quality and surrounding environment. The Grey Lynn Tunnel will be built between two shafts, from a Central Interceptor site at Western Springs and ending at a new shaft site at Tawariki Street. Projects such as the Grey Lynn Tunnel, the tunnel boring machine will pass under properties from between 15 to 60 metres. All property rights will be respected and the tunnel route will not be recorded on the property LIM.
Background
Grey Lynn and surrounding areas have some of the oldest wastewater pipe networks in Auckland with many, such as the Orakei main sewer, built early last century. As Auckland continues to grow, our networks are under increased pressure. As a result, diluted wastewater overflows into local waterways in the Cox’s Bay and Grey Lynn catchments almost every time it rains.
The Grey Lynn Tunnel is designed to intercept and divert overflows from local networks in Grey Lynn and the Orakei main sewer. Once completed, the wastewater flows will be transported through the proposed Grey Lynn tunnel via the Central Interceptor to our largest wastewater plant in Mangere for treatment.
The city centre, where Grey Lynn is located, is Auckland’s primary centre. It plays a critical role in the success of both Auckland and New Zealand. It is the main location for business, tourism, educational, cultural and civic activities in Auckland, and includes the city fringe areas of Parnell, Grafton, Newmarket, Newton, Grey Lynn and Ponsonby. The city centre is the largest and fastest growing employment centre in New Zealand.
Improvements in the city centre are ongoing and it will have to continue to change and adapt over the next 30 years to serve Aucklanders, but also as it competes in the global network of cities.
To complete the Grey Lynn Tunnel project, a new construction site will be required at Tawariki site, where we will create a shaft to extract the machine once tunnelling is complete and connect into local sewers which are at capacity when it rains. The main works at this site will be the shaft construction which is expected to take eight months to complete. The total construction will take approximately two and a half years to complete which will include, operational structures, removal of the tunnelling machine, closing the shaft and commissioning the tunnel. Construction is proposed to start at the Tawariki Street shaft site in 2023.
The proposed tunnel will:
- reduce diluted wastewater overflows, resulting in better water quality and surrounding environment
- cater for the growing Auckland population, now and for the next 100 years enable future connections and continued improvements to the wastewater system in the area
- be constructed by tunnel boring machine underground to limit effects on residents along the pipeline route
- be 4.5 metres in diameter, large enough for a double decker bus to travel through.
Invest Auckland Specialist
To find out more about this opportunity please contact Aldrin Thayalakal