Raw sewage has washed onto Wellington’s south coast again, this time after a power cut knocked out the pumps that carry the city’s wastewater to the troubled Moa Point treatment plant.
The city’s water provider, Tiaki Wai, confirmed untreated sewage spilled into Tarakena Bay for a short period last week before the flow was stopped. Warning signs were put up along the shoreline and people were told to stay out of the water.
According to RNZ, a Tiaki Wai spokesperson said “a temporary power cut at Wellington City Council’s sludge minimisation facility affected the pumps lifting wastewater up the hill to the Moa Point plant”. With the pumps down, the wastewater had nowhere to go but out through an emergency outfall and into the sea.
The health advice was the same as it has been through a long and difficult year for the capital’s coastline. People were asked to avoid swimming, surfing or kayaking anywhere between Owhiro Bay and Breaker Bay for 72 hours after the discharge stopped. That stretch takes in some of Wellington’s most popular walking and swimming spots, and the repeated warnings have become a familiar sight for residents who use the south coast.
The latest spill is small compared with the disaster that started it all. The Moa Point plant flooded and failed in February after heavy rain overwhelmed the site, and the damage has never been fully repaired. At the peak of that February failure, RNZ reported that about 3300 litres of untreated wastewater was pouring into the sea every second, with roughly three million litres going out over a single 24 hour period. Up to 70 million litres of untreated wastewater was discharged along the south coast in the days that followed.
Since then the plant has been running on a patched together basis, and every heavy downpour or equipment hiccup risks sending more untreated waste onto the beaches. Only days before the power cut, on 8 July, heavy rain forced another discharge into Tarakena Bay when the short outfall could not cope. The pattern has left swimmers, surfers, divers and dog walkers checking for warning signs before they go anywhere near the water.
The waste that reaches the sea is untreated and, during the worst events, unscreened, which means it carries everything that would normally be filtered and cleaned before release. Beyond the obvious health risk to people, there are concerns about what the repeated spills are doing to the marine life and shellfish beds that live along the rocky south coast. The area is home to paua, crayfish and reef fish, and locals have long gathered kaimoana there.
The organisation now carrying the problem is itself brand new. On 1 July, Wellington Water was folded into Tiaki Wai, a new entity that took over drinking water, wastewater and stormwater services across the metropolitan Wellington region. The change was part of the government’s water reforms, and it means the body that inherited Moa Point has been in existence for less than a fortnight while dealing with one of the country’s worst wastewater failures.
Repairs are under way but they are slow and expensive. Tiaki Wai says secondary treatment, the stage that actually cleans the wastewater, is on track to come back online in November once new blowers arrive and are installed. Concrete is being poured for modifications to the first ultraviolet treatment channel, described as the final piece of structural work before the UV lamps and other equipment can go back in. Even once the major work is finished, the provider has warned that some smaller repairs could take a few more months on top of that.
The people in charge have been careful not to promise too much. Speaking earlier this year as the new water entity was being set up, Tiaki Wai board chair Will Peet told RNZ that he could not guarantee a quick fix. “I wouldn’t be making commitments that all things will be in and done in 90 days, not at all,” he said. He added that “I don’t think anybody in my position should give you something that says absolute confidence”, and would not promise the south coast beaches would be safe to swim at by the following summer.
That caution matters because the plant sits alongside a much larger and more expensive project. Moa Point is next to a new sludge minimisation facility that has cost around half a billion dollars, and getting the treatment plant working properly again is tied up with bringing that wider site fully online. The February flood exposed how vulnerable the whole operation was to a single failure, and the power cut last week showed the same weakness has not gone away.
For now, the message to Wellingtonians is unchanged. Watch for the signs, stay out of the water when a spill has happened, and wait the 72 hours before heading back in. The city is being asked to live with an unreliable plant through the winter, in the hope that the promised November repairs finally bring the discharges to an end.
Have you been affected by the south coast spills, or do you swim and gather kaimoana in the area? Share your experience in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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