28 Sep 2023

Hauraki Gulf takes a hit as human waste flows into harbour

From Checkpoint, 5:27 pm on 28 September 2023

The sinkhole pumping sewage into the Waitematā Harbour is just another financial risk of running a city with old infrastructure, says Auckland Mayor Wayne Brown. 

It is expected it will take 10 days to fix a 13m-deep tomo that formed around one of the city's century-old sewer lines earlier this week

The resulting blockage caused sewage to flow into the harbour, with residents being warned not to swim at any inner-city beaches due to the high health risk. 

It was the third sinkhole in the city in recent months to cause major disruption to residents and businesses. 

On Thursday morning, Ngāti Whātua Ōrākei placed a rāhu across the Waitematā Harbour to address the environmental impacts of the sinkhole. The trust's chair, Marama Royal, said iwi were angry. 

"Ngāti Whātua Ōrākei has placed a rāhui to ensure that the mauri, or life force, of the Waitematā, can recover. We take the responsibility as kaitiaki seriously and will do our utmost best to ensure the protection and preservation of our tūtohu whenua and taiao." 

The incident retraumatised iwi, Royal said. 

"Back in the '40s and '50s, the sewage pipe actually came out into Ōkahu Bay and our village was down there. It killed all our kai moana. To hear that this is going to happen again, it just brings back all of those sad memories." 

Watercare said it would take 10 days to create a bypass around the affected area of pipe, but a permanent fix could be months away. 

Despite initial success clearing soil and debris from the pipe on Wednesday morning, by daylight, the sewer was blocked again. 

A main sewer line collapsed in Auckland, leaving a massive sinkhole 13 metres deep on a private property on St Georges Bay Road, Parnell, Auckland. 27 September 2023.

A main sewer line collapsed in Auckland, leaving a massive sinkhole 13 metres deep on a private property in Parnell, Auckland. Photo: RNZ / Jordan Dunn

Watercare chief of operations Mark Bourne said the incident was unprecedented

"In my 35 years of working in the water industry, I've never seen a blockage like this before.

"The nature of this failure is very similar to other failures that we have seen, which were a direct result of the flooding and storm events that have happened throughout this year." 

He said crews were working as fast as they could to repair the pipe. 

Parnell Business Association general manager Cheryl Adamson said businesses were frustrated. 

"Since the January floods, we have been extremely frustrated trying to deal with the silos that exist in Watercare, in Healthy Waters and Waka Kotahi. It's been extremely hard for businesses to navigate between these silos to get a resolution.   

"So, in general, we are very concerned about the ageing infrastructure in our suburb." 

Craig Horne owned a local cafe in the affected area, and said there had been a lot of chatter about the sinkhole. 

"It's worrying, a few people's carparks are gone, and we were wondering 'will it get any bigger?'" 

James Tapp worked up the road from the sinkhole, and said the council should go further than just addressing issues as they arise. 

"I would hope that they do also have a plan that is a bit more proactive in making sure that where there are weak points, that they are being reinforced. 

"It's weighing that up with the fact that people don't like road works, but if that means no more sinkholes that's probably a good thing." 

Watercare said an investigation will be put in place to understand the causes of the sewage blockage. 

[h]'Another financial risk' - Auckland mayor 

Some of Auckland's pipeline network was built back in the 1920s. 

Brown said it was time to give the network a revamp.  

"This pipe that failed was older than my grandfather and really, it should have been recommissioned years ago. It's just another one of the high financial risks of running a city that has old structures and meddling governments." 

Auckland mayor Wayne Brown speaks about his proposals for the city's budget.

Wayne Brown. Photo: RNZ / Marika Khabazi

He said sinkholes were a result of years of neglect. 

"[Auckland] is an old city by New Zealand standards and a lot of the old stuff has been known about for many mayors and several decades, and it's only slowly started to progress now. 

"It takes years to replace years of neglect," Brown said. 

Hauraki Gulf Forum co-chairperson Nicola McDonald agreed with Brown, telling RNZ's Checkpoint it highlighted the city's "ageing infrastructure" and a lack of investment, but also pointed to climate change.

"It is a serious overflow. We're looking at millions of litres of waste water going into the beautiful Waitematā Harbour. I guess for small mercies we're not in the full thrust of summer, but it is coming, so we want to make sure that we get on top of this and stop the flow as quickly as possible."

She said Auckland was not in a "third-world" country and "shouldn't be treating our environment like that". 

But a fix would not come cheap. McDonald said Auckland Council had various targeted rates that could be used to fund improvements, and the government's planned "affordable water reforms" would also help.