$44m water tunnel under St Marys Bay in Auckland raising issues for locals

Pollution levels at Westhaven led to a $44m water improvement project. Photo / Jason Oxenham

A big push by Auckland mayor Phil Goff to improve the city's beaches and water quality is being put to the test in the inner city suburbs of Herne Bay and St Marys Bay.

Goff is on the cusp of securing a $452 million boost to clean up beaches and harbours in his 10-year budget today - the same day a public meeting is being held to discuss a $44 million water improvement project.

The St Marys Bay/Masefield Beach project is designed to quickly improve water quality after visible signs of pollution at Westhaven in 2015 were tracked to wastewater and stormwater overflows from the cliff-side suburb.

The issues have taken time to emerge but for the sake of a bit of time we might get a more cohesive outcome

David Abbott, St Marys Bay Association

Local residents are keeping an open mind about drilling a wastewater and stormwater storage tunnel under houses built on the cliff face at St Marys Bay to Pt Erin where the water will be pumped to a main sewer or discharged into the harbour west of the Harbour Bridge.

They do, however, have a number of issues with the project and how it fits alongside other projects to improve water quality in the inner suburbs, including a plan to separate the combined wastewater and stormwater system in Herne Bay and St Marys Bay.

Stormwater diluted with wastewater could be pumped into the Waitemata Harbour near the Harbour Bridge.

"We have got the same goals and outcomes as Auckland Council's Healthy Waters. We want to improve water quality as quickly as possible. It's a question of the path we travel to get there," says David Abbott, of the St Marys Bay Association.

Abbott and Herne Bay Residents' Association member Dirk Hudig are not convinced the project dovetails with another water project to build a tunnel from Grey Lynn to Western Springs where a giant storage tunnel costing $1 billion will run to the Mangere wastewater treatment plant.

The Grey Lynn to Western Springs tunnel is expected to reduce the number of outfalls in the western inner city from 42 to 10, and reduce overflows from the 10 outfalls from more than 50 times a year to two-to-six within 10 years.

Abbott and Hudig - who are also members of the Stop Auckland Sewage Overflows Coalition - believe the council is galloping off to spend $44m when they don't know if it will deliver the promised benefits. They want an independent peer review of the project.

The number of outfalls in the inner western suburbs and overflows could be reduced. Photo / Dean Purcell

"The issues have taken time to emerge but for the sake of a bit of time we might get a more cohesive outcome," Abbott said.

The council declined to make anyone available to answer issues raised by Abbott and Hudig, saying "the regulatory process is under way and given that we have already received submissions we cannot provide additional information as the consent application has to stand alone".

Submissions on the St Marys Bay project close on June 19.

For more details on the project click here.