Photo: RNZ / Samuel Rillstone
DOC's becoming increasingly concerned about the 70 million litres of raw sewage being pumped into the sea around the capital near the marine reserve, putting several species at risk.
The beaches are off limits after Wellington's Moa Point waste water treatment plant failed, flooding the facility and sending massive amounts of untreated waste into the city's south coast and Taouteranga Marine Reserve.
There are plans to redirect the overflow much further out to sea during the plant's repair, but that could take months.
Meanwhile the environmental impacts of the discharge could have significant consequences for marine life.
Department of Conservation's principal marine science advisor Shane Geange told Checkpoint DOC were "extremely concerned".
"From an ecological perspective, raw sewage and waste water entering a marine environment poses an immediate and severe threat to a wide range of ecological functions and species, but I think the primary concern is around the public health concern which Greater Wellington health authorities are actively managing."
He said raw sewage carried bacteria, viruses and parasites that could impact sponges, muscles and fish that eat particles in the water.
"They can also accumulate in shell fish which make them unsafe for consumption."
He said the sewage could also impact penguin and how they regulate their bodies.
"Potentially you could get significant implication for the penguin population."
A Wellington Water spokesperson said they wanted to start getting the longfall pipe working - and hoped to have an update on that plan Friday afternoon.
They said that sewage would be partially screened, but noted raw sewage would still need to be pumped near the shore periodically.
"This is because the temporary arrangement only has limited capacity, which may be exceeded by network flows."
Preliminary inspection of the beginning of the 1.8km outfall pipe had been completed and divers were scheduled to check the end of the long outfall underwater over the weekend.
The spokesperson noted it was likely that more odour would become apparent near the Moa Point plant.
That was due to the sewage flooding onsite, the operational work needed to respond to the damage at the plant, and the lack of odour treatment onsite.
"We appreciate the significant impact odour can have on the community, and are doing all we can to reduce the level of odour and the timeframe of any potential impact," they said.
"This is a top priority, and we want to assure you that our teams are considering how we can mitigate odour every step of the way."
'Pretty disappointing'
Geange said DOC was working with Greater Wellington Regional Council to figure out how far the sewage had spread.
"In the process of undertaking a bunch of sampling to determine the concentration of contaminates within the sea water and how far they have spread at the moment..."
The marine reserve is 2km from the waste water pipe.
He said the sea water would "rapidly" dilute the sewage, but not enough to destroy the contaminates.
The environmental impacts of the discharge could have significant consequences for marine life. Photo: RNZ / Samuel Rillstone
Geange said mass fatality was his worst fear, but was highly unlikely.
"It's pretty disappointing from an environmental perspective," he said.
'Environmental disaster' - Wellington Mayor
Wellington's mayor Andrew Little earlier told Morning Report there must be an independent inquiry into what happened, which he's labelled a "catastrophic failure" and an "environmental disaster".
"This is a sewage plant processing the sewage for a big city, and it has completely failed, it just completely stopped," he said.
"Plants like this should not suffer the kind of catastrophic failure that we've seen."
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