Tenders submitted for Watercare’s Central Interceptor project

Watercare’s Central Interceptor project has reached a significant milestone with tenders handed in today from the four short-listed contractors.

The 13-kilometre Central Interceptor wastewater tunnel will run deep below Auckland – 110 metres at its deepest point – from Western Springs to a new pump station at the Māngere Wastewater Treatment Plant.

At 4.5 metres diameter, it will be Auckland’s largest wastewater tunnel and the biggest wastewater project ever undertaken in New Zealand.

The four short-listed contractors were chosen in March and the Request for Proposal released in May. They’ve had four months to prepare their submissions.

The 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 Soletanche Bachy.
Watercare chief executive Raveen Jaduram says: “The Central Interceptor is exciting for Auckland. One, because it will improve our environment; two, because Auckland is growing rapidly and this will allow for that growth; and three, it creates employment and opportunities for the city.”

A lot of the flows currently going into the Eastern Interceptor will be diverted to the Central Interceptor, which will free up capacity for development in east Auckland. These flows are significant – equivalent to the volume produced by over 30,000 houses.

“In addition to providing for growth, it will also reduce the volume of overflows into the harbour,” Jaduram says.

“Parts of the old Auckland City Council area have no stormwater system, so when it rains the stormwater goes into the wastewater pipes and then overflows into streams and beaches.

“It was designed to do that in the early 1900s because it was acceptable back then. But Aucklanders’ expectations have changed – we want a clean and swimmable water environment.”

The Central Interceptor will address wet-weather overflows by collecting the wastewater and stormwater from these overflow points and transporting it to Māngere for treatment.

“It’s expected to reduce the volume of overflows by at least 80 per cent,” Jaduram says. “It also provides time for Auckland Council to install stormwater pipes in areas where there are none.”

The project has been on Watercare’s agenda for many years, and its funding is already catered for in the company’s pricing plan, Jaduram says.

“It’s part of the $5.8 billion we will be spending on upgrading and expanding our infrastructure over the next decade.”

Evaluating the tenders to identify a preferred bidder is expected to take about two months.

Central Interceptor executive programme director Shayne Cunis says stringent probity measures are being taken to protect the tender process.

“The security measures we’re taking are in line with what would be expected of a project of this scale. The Central Interceptor is a massive undertaking, and the contractors have put a lot of time and resource into their tenders. We will ensure our process for protecting their submissions is water-tight. Trust and confidence in Watercare’s processes have always been paramount. This is no exception.”

An announcement about the successful contractor will likely be made in February 2019. Construction will begin next year and continue until 2025.