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We're working to reinstate flood-damaged Pukekohe Water Treatment Plant  cover

We're working to reinstate flood-damaged Pukekohe Water Treatment Plant

18 September 2024

Work is underway to bring the Pukekohe Water Treatment Plant back into service, after it suffered significant damage during last year’s Auckland Anniversary floods.

The flood destroyed most of the plant’s critical infrastructure, from the chemical dosing systems and drives for the pumps to the electrical equipment in the control room.

Since then, most of Pukekohe’s water supply has come from the Waikato River, having been treated at the Waikato Water Treatment Plant and then distributed to the Pukekohe community.

Head of water Sharon Danks says, the team is working at pace with construction partner Cassidy Construction to have the plant operational by the end of February.

“Having the plant operational by early next year is a priority as it will enable us to increase water production by six million litres a day at a time when water demand is at its peak.

“Pukekohe is part of our interconnected metropolitan water network, so an extra six million litres here is a boost for the whole of Auckland.”

Capital delivery general manager Suzanne Lucas says, instead of rebuilding the treatment plant as a mirror image of its former self, we are spending about $4 million to reconfigure and upgrade the plant to reduce flood risk.

“One way we’re doing this is by relocating the critical components from the control room – which was severely flooded – to higher locations within the treatment plant site to make it more resilient to another flood.

“The original control room will be rehabilitated and retained for non-operational purposes.”

Lucas says to further increase the resilience of the plant new ducts will be installed underground using a thrusting technique to better protect major electricity cables from flooding.

“Using this technique, we’ll be able to feed and install the cabling into the ground without causing too much soil disturbance and enable us to get the work done faster.”

Lucas says the rehabilitation is an opportunity to upgrade a chemical dosing system to use self-generated chemicals rather than chemicals delivered in liquid form.

“Using the generation system, we can produce fresher chemicals as required, ensuring the water produced has minimal residual chlorates.

“It also allows for precise control of the concentration and dosage of hypochlorite, resulting in more efficient and effective treatment.”

Lucas says no traffic disruptions are expected to be caused by the rehabilitation works as they will take place inside the water treatment plant and within the reserve.

“There will be no disruption to traffic, but there will be some small exclusion zones established within the reserve.

“The work may generate some noise and vibration; however, we aim to keep this to a minimum and within Auckland Council consent conditions.”