Key section of century-old Ōrākei Main Sewer secured for another 100 years

A key section of a century-old sewer has been granted another 100 years of service life, thanks to complex rehabilitation work in a live sewer environment that will keep it serving Tāmaki Makaurau for generations to come.

Watercare has wrapped up its remedial work on the Ōrākei Main Sewer following a section collapsing in 2023.

The final stage of the work, which was recently completed, involved relining a section of the sewer between two manholes, which were also upgraded.

Deputy mayor Desley Simpson visited Alberon Reserve in Parnell to see the reinstated area of the park that previously housed the 13-metre-deep shaft built so crews could access the sewer and install the liner.

“It’s fantastic to see the revitalisation of Alberon Reserve. When I was here maybe a year ago, it was still a construction site.

“On behalf of the people of Parnell, thank you to Watercare. To the people of Parnell and surrounds, I want to say thank you for your patience. We now have our Ōrākei Main Sewer section here future-proofed and the beautiful park put back for the people of Auckland to enjoy.”

Giving existing infrastructure a new lease of life is a key focus of Watercare’s $15.2 billion 10-year Capital Investment Plan. By renewing assets where possible, Watercare can maximise value from existing infrastructure while continuing to invest in the new networks needed to support Auckland's future growth.

Deputy Mayor Desley Simpson with the Watercare team

Watercare capital delivery general manager Mike Marsden says relining the sewer essentially creates a new sewer inside the existing one.

“We installed a new liner inside the existing sewer, effectively creating a new pipe within the old one. The liner is made from glass-reinforced plastic and is expected to last another 100 years, helping ensure reliable wastewater services for Aucklanders while making the most of existing infrastructure.”

The liner for the Ōrākei Main Sewer was custom-made and manufactured in Dubai due to the sewer’s unique egg shape, which is known as oviform, and the final stage of the work used about 79 liner segments.

Marsden says the work was done in a live sewer environment which created challenges.

“We had to make sure the wastewater flows in the sewer were at safe levels for the crew to do the work, which meant a lot of it was done at night when flows are lower. The work was also weather dependent as heavy rain could raise the sewer levels to the point where it’s unsafe to work.”

Alberon Reserve has now been reinstated with planting and new grass seed.

Marsden says it’s great to be able to return it to the community.

“We sincerely appreciate the community’s patience while we took up part of the reserve for this essential work. The site has now been reinstated for people to enjoy.”

Watercare is planning to rehabilitate more sections of the Ōrākei Main Sewer as part of its $1.1 billion wastewater interceptor renewals programme.

The programme reflects Watercare's focus on investing in existing infrastructure to improve reliability, reduce the risk of service disruptions to deliver long-term value for Auckland.