Central Interceptor Main Works

Auckland, New Zeland

The Central Interceptor is a wastewater tunnel that will run between Grey Lynn and the Mangere Wastewater Treatment Plant. The tunnel will run underground at a depth of between 15 and 110 meters. It will cross the Manukau Harbour at about 15 meters below the seabed. Along the route it will connect to the existing wastewater network, which will divert flows and overflows into the tunnel.

The Works include a 14.7km long main tunnel excavated with a 5.45 m diameter Earth Pressure Balance Tunnel Boring Machine (EPB TBM)  and two underground links of overall 4.3km excavated with two micro-TBMs, of the diameter of approximately 3m each. The line will encounter 16 shafts reaching up to a depth of 80 meters, as well as numerous connecting sewers, chambers, control facilities and air treatment facilities.

The project provides a supersized wastewater tunnel that will significantly reduce waste water overflows into central Auckland’s waterways. The increased capacity in the wastewater network also provides for future growth and development on the Auckland Isthmus for the next 50 years and beyond.