Construction began today on Watercare’s critical bypass project that will transfer wastewater from the manholes on either side of the Ōrākei main sewer sinkhole and pipe blockage site.

The bypass is an essential component of the work to end or significantly reduce wastewater overflows into the Waitematā Harbour as soon as possible.

Watercare chief operations officer Mark Bourne says the design and route was confirmed today and work began immediately.

“Today we’ve started the site preparation and traffic management so tomorrow we can get to work laying the first sections of pipe.

“With the design confirmed and work underway, we now have a better idea on when we’re likely to complete the bypass.

“Due to the complexity and scale of the job, we don’t expect this to be completed for another two weeks.

“The position of the existing underground services is a complicating factor, and we’ll need to move an underground gas line as part of the project.

“The large pumps need to be buried underground, and we now understand it will take at least 10 days to excavate the chamber and install them. Once they’re installed, the commissioning process is another two days.

“The team at Watercare, like everyone in Auckland, wants to see these overflows end as soon as possible. Our role in the wastewater side of the business is about protecting the environment, and it’s a role we’re all passionate about. We are continuing to push ahead with work to clear the blockage in the pipe as soon as possible.

“When the bypass is operational, we expect it will significantly reduce the overflows. As some of the catchments that feed into the Ōrākei main sewer are historic combined wastewater and stormwater networks, the flow in the sewer increases in wet weather and decreases in dry weather.

“It is likely that in wet weather, there will be some overflows even after the bypass is in place – but the volume of these would be much smaller than we’re seeing now.”

Auckland Council’s Safe Networks and Safeswim teams have been conducting sampling at Auckland beaches since the overflows began on Wednesday last week, after the sinkhole above the Ōrākei main sewer widened and sent ground material tumbling into the pipe, blocking it.

When the wastewater overflows end, sampling will be undertaken to confirm water quality at Waitematā beaches has returned to normal.

Consistent with NZ Guidelines for recreational water, this will require multiple samples over a number of days that signal the water is safe for swimming before water quality alerts can be removed.

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