The 4.5m-diameter Central Interceptor is designed to help reduce combined wastewater and stormwater overflows to local waterways and Waitemata Harbour.
The shortlisted contractors are:
- CPB Contractors;
- Ghella-Abergeldie Harker Joint Venture;
- Pacific Networks, comprising McConnell Dowell, Fletcher Construction and Obayashi;
- Vinci Joint Venture, comprising Vinci Construction Grands Projets, HEB Construction and Solentache Bachy.
Central Interceptor executive programme director Shayne Cunis said: “All four groups have demonstrated that they have the ability and experience to deliver this project to the required standard, while adding significant value to the project.”
The tunnel will be constructed at depths of up to 110m and will run 13km between Western Springs and the Mangere Wastewater Treatment Plant. Connections to existing networks along the route will enable flows and overflows will be diverted into the tunnel before it crosses the Manukau Harbour below the seabed.
Design and technical documentation will be released in March, and the request for proposals will be issued to the shortlisted contractors in May.