South Western Interceptor Extension
Meeting the needs of a growing Auckland
Our construction of the South Western Interceptor in 1997 saw the first use of large diameter micro-tunnelling techniques in New Zealand. We used a Tunnel Boring Machine install two km of 1900mm diameter pipeline in an environmentally sensitive area adjacent to the approach path to Auckland Airport.
Fifteen years later, we extended the pipeline to Manurewa to accommodate rapid population growth in Auckland’s southern suburbs.
we extended the pipeline to Manurewa to accommodate rapid population growth in Auckland’s southern suburbs
Due to the complex ground conditions we used three different methodologies to install the 2.3km, 900mm diameter wastewater pipe: open trenching, directional drilling and pipe jacking. A TBM was used for the pipe-jacking section.
We also constructed a new pump station to replace an ageing pump station at Manukau’s Wattle Farm Reserve which had reached the end of its serviceable life. The pump station was constructed using in-situ reinforced concrete wet- and dry-well internal walls and pre-cast panel roof.
The project involved significant mechanical & electrical works, including installation of four 320Kw pumps, numerous 700-900mm diameter valves, pipework, HVAC system, cooling water system and odour removal. The project team was also responsible for managing the sub-contract electrical works which included installation of a new control system, cabling, switchboard and float switches.
The extension to the South Western Interceptor and the new pump station provided for future growth in South Auckland in as well as reducing the frequency and volume of wastewater overflows to the Manukau Harbour.