New Tunnelling Extension to Enhance Wastewater Management on Watercare’s Central Interceptor

We are proud to announce that we will be continuing to work with Watercare to extend the Central Interceptor north towards Point Erin Park, Herne Bay.

Since the contract was signed in 2019, Ghella and Abergeldie have been working together to construct the Central Interceptor for Watercare. This new extension will add just over 1.5km to the existing 14.7km tunnel route, making New Zealand's largest wastewater tunnel even larger. The tunnel will now stretch a total of 16.2km from Māngere Wastewater Treatment Plant to Point Erin Park, Herne Bay.

Our tunnel boring machine will continue from Tawariki St, Grey Lynn, and will bore at depths of between 17m and 60m to arrive 30m below the surface at Point Erin Park. Watercare gained consent for the extension in early 2024.

This extension will enable current and future projects to transfer wastewater in the Central Interceptor tunnel and relieve much-needed pressure on smaller wastewater networks, reducing the risk of overflows and cleaning up the local beaches.