More swimming days coming for St Mary's Bay and Masefield Beach

Last Updated : 09 Dec 2019
St Marys Bay tunnel

A landmark stormwater project will get underway in early 2020 to clean up St Mary’s Bay and Masefield Beach, two historic and popular inner-city beaches.

Auckland Mayor Phil Goff says the project is part of the council’s ten-year work programme to dramatically improve the city’s water quality within a decade.

“For over a century Auckland failed to invest in the infrastructure needed to stop stormwater mixing with wastewater and causing wastewater overflows onto our beaches every time it rained.

“Now, thanks to Aucklanders who overwhelmingly supported the Water Quality Targeted Rate, we’re investing at historic levels to build the infrastructure our city needs to fix those issues and meet rapid population growth.”

The installation of the new pipeline will collect stormwater flows, screen them and discharge them well away from shore where they will have the least impact on recreational activities.

“We want to restore these beaches to being thriving, lively places where people come together to enjoy themselves and to learn about the sea,” says Healthy Waters General Manager Craig McIlroy.

“We estimate that when our project is complete, St Mary’s Bay will be able to be used safely at least 95% of the time, by everyone including swimmers, children learning to sail, and dragon boaters.”

Construction will begin in the Pt Erin area in January. The pipeline will tunnel eastwards towards the intersection of London and New Street and run underground for approximately one kilometre, between 13 and 25 metres deep.

This method has been used in many parts of Auckland for stormwater and wastewater construction because it lowers the impact on properties, people and traffic.

Healthy Waters project manager Gwilym van Hoffen says he is excited to begin this transformative project.

“Though this is the most significant stormwater project in central Auckland right now, people in St Mary’s Bay will only see construction works at three above-ground sites in London St, St Mary’s Road Reserve and at Pt Erin Reserve,” says Gwilym.

“We chose to tunnel underground because it causes the least disturbance to people in the area, and we’re using the latest in German boring technology to make it happen.”

Construction of the pumping and screening station in the reserve at Pt Erin will temporarily reduce access to the area. The contractors will ensure areas of the park are retained for public use during the construction period.

The St Mary’s Bay pipeline is the first part of an integrated package of wastewater and stormwater upgrades to be delivered over the next eight years as part of the Western Isthmus Programme – a joint undertaking by Auckland Council and Watercare.

For the St Mary’s Bay and Herne Bay catchments, the rest of the package involves Watercare separating stormwater and wastewater into separate pipes and renewing a century-old wastewater sewer. This work will get underway in early 2020 with the rebuild of a manhole in the existing combined sewer network.

Watercare's Network Efficiency Manager Anin Nama, who is directing the Western Isthmus Programme, says the separation of the combined stormwater and wastewater network, together with the stormwater pipeline, will see the occurrence of wastewater overflows fall dramatically, and be eliminated from St Mary’s Bay.

“Currently, St Mary’s Bay and Masefield Beach receive wet-weather overflows around 100 times a year—essentially every time it rains. By the time our projects are complete, we expect the frequency to drop to two-to-six times a year or less at the new outfall location.”

Nama says Auckland Council’s stormwater pipeline will provide considerable benefits before the wastewater and stormwater separation work is carried out.

“The stormwater pipeline will be able to store excess combined flows during wet-weather, enabling it to be pumped back into the wastewater network and sent to a plant for treatment. This too is good news for these local beaches.”

“The St Mary’s Bay project is an important part of an Auckland-wide programme of works that will deliver improvements to water quality across our region,” says Craig Mcilroy.

“Our projects will mean cleaner beaches, rivers and waterways for Aucklanders, and a healthier environment for bird and marine life in our city.”

This stormwater pipeline project is funded by the Auckland Council Water Quality Targeted Rate.

The sewer separation project is jointly funded by Healthy Waters and Watercare and delivered by Watercare.

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