Up to 13 million litres of sewage overflowing into harbour after sinkhole, bypass work begins
One conservative estimate would see 12.9 million litres entering Auckland's harbour each day – the equivalent of nearly six Olympic-sized swimming pools. The collapse of a Central Auckland sewer line has resulted in a massive sewage overflow pouring into Waitemata Habour, creating a large sinkhole and the closure of some Auckland beaches. Up to 13 million litres of sewage is still overflowing into Auckland’s waterways after part of the sewer line collapsed. Work for a temporary fix began on Tuesday, with samples taken from multiple sites and depths to be tested for a range of things. According to Watercare, their plans for an overland bypass are still on track for October 17.
发表 : 2年前 经过 Ryan Anderson 在 Environment
The collapse of a Central Auckland sewer line has resulted in a massive sewage overflow pouring into Waitemata Habour, created a large sinkhole, and seen the closure of some Auckland beaches.
Up to 13 million litres of sewage is still overflowing into Auckland’s waterways after part of the sewer line collapsed, creating a sinkhole.
A company undertaking work at a property on St Georges Bay Rd, above the Orakei Main Sewer, alerted Watercare to a hole in the ground in late September.
Part of the Central Auckland sewer line, the 2.1 metre-diametre brick sewer is approximately 13 metres underground and serves large parts of central and west Auckland. The top of the wastewater pipe has collapsed.
Weeks on, several hundred litres per second is still overflowing into the harbour, according to Watercare, with work for a temporary fix beginning on Tuesday.
While Watercare said it doesn’t have flow meters at the overflow location, a conservative estimate of 150 litres per second would mean 12,960,000 litres would be entering the harbour per day – the equivalent of nearly six Olympic-sized swimming pools.
“It’s a high-volume overflow and we’re doing everything we possibly can to put an end to it as soon as possible.”
The catchments that feed into the Ōrākei main sewer are combined stormwater and wastewater, they said, so the volume would increase or decrease depending on the weather.
Watercare environmental care manager Nathaniel Wilson said they had been working with marine environmental experts, Ngāti Whātua Ōrākei and other mana whenua to figure out a monitoring programme to assess the impact on the Waitematā Harbour.
Further to the sampling that was undertaken in the first week, a daily regime began recently, where samples are taken from multiple sites and depths to be tested for a range of things, he said.
Bags of oysters have been placed at locations around Westhaven and Okahu Bay, which will be left in place for the duration of the sampling programme, Wilson said.
“Samples from these bags will be tested every fortnight for bacteria and heavy metals.”
Routine inspections of debris in the harbour has not seen any more than normal, he said.
According to Watercare, their plans for an overland bypass were still on track for October 17.
Watercare chief operations officer Mark Bourne previously said that there is no quick fix for the blockage in the Orakei main sewer and the repair is likely to be the largest wastewater bypass solution that’s ever been put in place in New Zealand.
“Unfortunately, these overland solutions can cause smells.”
According to SafeSwim, as of Monday evening, all 22 of their monitored sites around the Waitematā harbour were under a ‘do not swim alert’.
The locations had been labelled ‘very high risk’ due to the waterwater overflow.
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