Water treatment plant back in service for Muriwai

Muriwai Water Treatment Plant
Today marks a milestone in Auckland’s post-cyclone recovery with the Muriwai Water Treatment Plant returning to service.

The Muriwai Water Treatment Plant was taken out of service after Cyclone Gabrielle, when a slip caused by the February 14 weather event buried and damaged part of the plant and reservoir.

To ensure Muriwai residents had access to safe drinking water immediately after the cyclone, we stationed a tanker in front of the Sand Dunz Cafe.

Head of production Peter Rogers says within 11 days of the cyclone, our team had put in place a temporary solution on Motutara Road opposite the fire station to restore water to customers.

“The temporary solution was a fixed water tanker serving as a reservoir and a mobile pumping station that distributed drinking water back into the network.

“We kept the temporary reservoir topped up with tanker deliveries throughout the day, usually running from 6am to 11pm to keep up with water demand.

“We know our customers really appreciated this service but tankering in water obviously isn’t ideal, so I think everyone will be really happy to have the water treatment plant back up and running again.”

Inside the Muriwai Water Treatment Plant
Taking a look around the plant

Upgrades and renewals general manager Suzanne Lucas says work to reinstate the water treatment plant has been underway since April.

“Our teams secured the site by clearing slip material and debris and stabilising the exposed slip face on site.

“We relocated cables and pipework to better-protected positions, replaced the damaged plastic raw water storage tank with a partially-buried concrete tank and improved tanker access to the treatment plant.”

While these actions have significantly increased the plant's resilience in the event of future landslips, the plant won’t be able to treat as much water as it previously could because access to one of the springs located on Motutara Road has been blocked, says Lucas.

“This spring couldn’t be reinstated due to safety concerns around stabilising the slip face and potential further slips, so the water treatment plant can now draw from only two springs.

“Our access to the treatment plant site is also restricted during and after wet weather due to ongoing geotechnical risks related to the landslide.

“There is a chance we may need to bring back the temporary water supply solution – if for some reason we are unable to draw water from one of the springs or top up supply at the water treatment site.

“We’ll also be encouraging our Muriwai customers to continue to use water wisely, particularly over the summer months when water usage traditionally goes up.”

Lucas says some Muriwai customers may experience discoloured water temporarily when the treatment plant goes into service.

“Because the direction of the water flow will change when we switch over, it may stir up some sedimentation in the pipes that could cause discoloured water for a short period.

“To help mitigate the chance of discoloured water in the network, our team are out in the community actively flushing the network, testing the water, and addressing the issues if they should occur.

“If customers experience discoloured water, we recommend running their outside tap for up to 5 minutes to clear their private pipes. If the problem continues, we ask them to call us on 09 442 2222 or log a fault on our website so we can investigate.”

Exterior of the Muriwai Water Treatment Plant
A bird's-eye view of the plant

Auckland Deputy Mayor Desley Simpson thanks the community for their patience and understanding, and our team for getting the Muriwai Water Treatment Plant back into service.

“It’s great to share some good news with Muriwai residents, who have shown tremendous resilience over the past few months.

“While there is still work to do for many, this is a sign of things finally turning a corner and returning to normal with the permanent water source back in action.”