Auckland’s water authority has completed work to bypass sewage around a collapsed and blocked sewer main but says 'there will still be overflows' into the harbour when it rains. Video / NZ Herald
Auckland’s water authority has completed work to bypass sewage around a collapsed and blocked sewer main in Parnell but says “there will still be overflows” into the harbour when it rains.
While the city hit a 23C high today, a least 22 beaches remain closed in the Waitematā Habour due to contamination from sewage pouring in from the blocked sewer.
Deputy Mayor Desley Simpson described the sinkhole as “the size of a tennis court”, saying the damage was the result of severe weather and lots of rain.
Watercare started work on a bypass solution, which would pump sewage around the blockage between different manholes, on Thursday, September 28.
Watercare chief operations officer Mark Bourne (left) and Deputy Mayor Desley Simpson. Photo / Watercare
Watercare’s chief operations officer Mark Bourne said there had been “a monumental effort from our staff, contractors and suppliers to get the bypass planned, the pipes laid, the pump station excavated and concreted, and have six large temporary pumps installed and tested”.
Bourne said a project of this scale would “normally take several months” to complete.
“So I’m incredibly proud of the whole team involved for their hard work and dedication to this critical project,” he said.
The temporary pump station installed to divert wastewater can handle 600-litres-a-second flows, which should be “sufficient to handle normal flows during dry weather”, Bourne said.
The temporary pump station installed to divert wastewater can handle 600-litres-a-second flows, which should be "sufficient to handle normal flows during dry weather", Watercare chief operations officer Mark Bourne said. Photo / Watercare
“But these temporary pumps are more susceptible to blockages than our standard network pumps, so it will be more important than ever for people to only flush the 3Ps - pee, poo and toilet paper. Please don’t flush wet wipes or any other rubbish.
“Just as there was prior to the sinkhole developing, in wet weather, there will still be overflows into the Waitematā Harbour.”
There were higher flows during rain because some of the water catchments feeding into the sewer were historical combined stormwater and wastewater catchments, he said.
Local iwi Ngāti Whātua Ōrākei’s rāhui over the harbour would remain in place and Watercare encouraged people to check Safeswim for updates on water quality at the city’s beaches.
Watercare started work on a bypass solution, which would pump sewage around the blockage between different manholes, on Thursday, September 28. Photo / Watercare
Beaches west of Ōkahu Bay and south of Torpedo Bay are closed. Swimming is not advised at Mission Bay, Kohimarama and St Heliers.
Watercare has begun a “targeted daily harbour sampling regime” after advice from marine environmental experts and mana whenua.
“We are also placing bags of oysters at locations from Westhaven to Ōkahu Bay. Samples from these bags will be tested every fortnight for bacteria and heavy metals. This information will supplement our data from the water sampling programme,” Bourne said.
“We’ve engaged the Sea Cleaners Trust to carry out routine inspections of the harbour and report back to us. So far, they haven’t seen any more debris in the harbour than they normally would.”
