Preferred contractor selected for Auckland interceptor 29 Nov 2018

The Ghella-Abergeldie Harker JV has been selected as the preferred bidder for construction of the Central Interceptor wastewater tunnel in New Zealand. It is selected from four contractors competing for the project, the other three being CPB Contractors; the Pacific Networks JV of McConnell Dowell, Fletcher Construction and Obayashi; and a JV of Vinci, HEB Construction and Soletanche Bachy.

The Central Interceptor wastewater project plan

Owner of the project, Watercare of Auckland, says it has run a rigorous procurement process involving prequalification of contractors through the expression of interest stage and working with the bidders through the request for proposal stage. “Often when a company undertakes a project of this size, it tenders for a design-build procurement," said Watercare Chief Executive Raveen Jaduram. "By contrast, we have already completed the detailed design. This means all four contractors had a very clear understanding of our project and as a result, there is better pricing and less risk for both Watercare and the contractors.”

The tunnel will run for 13km from Western Springs to a new pump station at the Māngere Wastewater Treatment Plant (Fig 1). At 4.5m diameter, it will be the largest wastewater tunnel undertaken in Auckland as well as ever undertaken in New Zealand.

Jaduram describes the Central Interceptor as a major investment for Auckland. “This project will improve the health of the waterways of our city by reducing wet-weather overflows and provide for population growth. It will also create employment and opportunities for the city. Over the next two months, we will continue our due diligence, working with the preferred joint venture on a range of conditions and issues relating to its bid. If the conditions and issues can be successfully worked through, the Central Interceptor team will take a recommendation to our Board in the first quarter of 2019. If the conditions and issues cannot be worked through successfully, then we will start liaising with the second bidder which cannot be named at this stage."

Francesco Saibene, New Zealand representative for Ghella, said that both joint venture partners are delighted to have the opportunity to further progress its tender. “The team at Watercare is running a professional and robust procurement process which makes us confident that should we be successful, we will be able to work collaboratively to deliver an outstanding result for Auckland and its people.”

The Ghella-Abergeldie Harker JV combines more than 30 years of tunnelling expertise in New Zealand with more than 150 years of Italian and international tunnelling experience and ability. Ghella has successfully completed numerous projects worldwide, including the Legacy Way highway tunnels in Brisbane, Australia, which achieved world records in tunnel boring machine excavation, and is working on the Follo Line railway tunnels in Oslo, Norway, the Sydney Metro tunnels, and the Riachuelo sewage system in Buenos Aires.

Abergeldie Harker is one of the leading shaft sinking and pipejacking contractors in New Zealand. Its parent company Abergeldie is one of the top three water industry contractors in Australia with extensive experience working on major water and wastewater assets throughout Australia.

Aims of the Central Interceptor wastewater project

With NZ$10.1 billion in infrastructure, Watercare it is one of largest companies by asset base in New Zealand and has a strong track record of delivering infrastructure projects. Between 2007 and 2010, Watercare carried out a NZ$118-million project to replace a 90-year-old sewer pipe that crossed Hobson Bay with a 3km long wastewater tunnel that connects to a large pump station at Orakei. “With the Hobson Bay project, we successfully used a TBM to construct a 3.7m diameter tunnel to connect two shafts and a large pump station. The Central Interceptor project is similar in many ways, only on a larger scale,” said Jaduram.

The Central Interceptor will reduce combine sewer overflows into central Auckland waterways that flow into Waitematā Harbour and direct all flow to the Māngere treatment plant.

The project has been on the Watercare agenda for many years and its funding is secured in the company pricing plan. “The Central Interceptor is part of the NZ$5.8 billion we will be spending on upgrading and expanding our infrastructure over the next decade,” said Jaduram. Construction will begin next year (2019) and continue until 2025.