Wellington stream turned bright orange by landfill leachate

Friday, 17 July 2020

Owhiro Bay stream has been showing some unusual colours since heavy rain in June.

A flowing cocktail of landfill runoff has turned a Wellington stream bright orange.

Residents say they’ve seen the Owhiro Stream run from red to orange as it transports substances from Wellington’s landfills to the sea – to a legally protected marine reserve off the city’s South Coast.

Greater Wellington Regional Council spokesman Stephen Heath said there’s little they can say, as they are “in the process of investigating the incident”.

Leachate from the stream runs from the landfills to the sea off the Wellington South Coast.

“Given that we are currently investigating the source, nature and extent of the discolouration of the stream – which we of course acknowledge occurred - it would be inappropriate to make any substantial comment on this matter.”

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Resident Eugene Doyle, of the Owhiro Bay Residents Association, said the stream looked like it was full of an “orange-reddish material”, and believed it was manganese, iron and ammonia leaching from a landfill.

Residents are also concerned about the amount of rubbish coming down the stream after significant rain events.

“We chased Greater Wellington Regional Council to see if they’d got the lab results … three weeks later, they have no lab results,” he said.

Owhiro Stream has a long history of pollution.

In 2016, the T&T Landfills firm was linked to contamination in the stream and placed under investigation due to breaching its resource consent conditions.

The council ordered the landfill to divert water away from the site and create a filtering wetland in 2017.

In March this year, it was discovered wastewater had been mistakenly spilling into the stream for eight years after pipes were incorrectly laid in a new subdivision.

The landfill-contaminated Owhiro Stream, just before it meets Taputeranga Marine Reserve on Wellington's South Coast.

Doyle said Owhiro Bay residents wanted something done, and quickly.

“Greater Wellington Regional Council is a little bit like the Wizard of Oz, they’re full of fire and fury when it comes to environmental causes, but they don’t actually back up their talk.”

Doyle said the colours in the stream were most noticeable in late June, after the heavy rain.

“It’s a known problem and it’s happened on multiple occasions.”

Emails sent to Doyle from a council staff member suggest T&T landfills had failed to respond to three emails from the council over the last two months.

“If they do not respond in the next week we will consider escalating this,” one of the emails says.

The council is awaiting results from the laboratory from testing the stream, which will be assessed by a freshwater expert, along with the quarterly monitoring results provided by T&T.

Heath said the council would continue to investigate the source of the issue.

A T&T Landfill spokeswoman said the council’s investigations were not aimed at them specifically.

”There are three landfills running in to that stream … we’re in close contact with the council.”

They were aware of testing being carried out on the stream, she said.

”There’s a conversation between all landfills about it.”