Six years since Ghella and Abergeldie signed the Central Interceptor contract

March 14, 2025, marks the sixth anniversary of the contract signing between Ghella and Abergeldie, together with Watercare for the Central Interceptor: Auckland’s largest wastewater infrastructure project.

Watercare’s 16.2 km long wastewater tunnel will be the longest bored tunnel in New Zealand. In older parts of Auckland, there is a combined sewage/rainwater network. During heavy rain, the system becomes overwhelmed, and overflows occur into local streams and beaches. The Central Interceptor tunnel will capture the combined flows and convey them to Māngere Wastewater Treatment Plant for processing. The Central Interceptor project will reduce wet weather overflows significantly and will improve the water quality of local waterways. The tunnel will be 4.5 m in diameter and will start in Grey Lynn and run underneath the Manukau Harbour to central Auckland to depths of between 15m and 100m below the surface.

Six years on, the Central Interceptor is set to reduce wastewater overflows, create cleaner waterways, and future-proof Auckland’s wastewater network for the next 100 years.