Auckland's water drought gets a small boost from Pukekohe water bores

Auckland's record-breaking drought got a small boost yesterday when two bores in Pukekohe were brought back into service.

After being out of action since 2013, Watercare started drawing up to 5 million litres a day from the Hickeys water treatment plant in the South Auckland town.

It comes in the midst of a year-long drought crisis in Auckland, water use set to climb through summer and the possibility of more severe water restrictions.

The city's dams were 67.5 per cent full yesterday, compared to the normal figure of 91.5 per cent full for this time of the year.

The city is currently using about 400 million litres of water a day - less than the 415MLD target for October.

Earlier this month, water restrictions were eased for businesses, but councillors rejected a proposal by the board of Watercare to lift restrictions by residents on outdoor water use to avoid the risk of severe water restrictions later in summer.

Watercare acting chief executive Marlon Bridge said the return to service of the Pukekohe bores is part of a $224 million response to the drought.

"Our Hūnua dams in particular are still recovering from this year's drought, so we have been minimising the abstraction from these dams to allow them to replenish.

"Being able to treat and deliver up to 5 million litres a day from an underground aquifer means we can continue to ease the pressure on these dams over summer," Bridge said.

Watercare head of operations excellence Priyan Perera said the $11.5 million modular treatment plant at Pukekohe is simple in design but uses sophisticated technology to produce the highest-quality water.

"We pump the water from an underground aquifer with two bores about 270m deep. We then dose it with chlorine and use ultra-filtration membrane filters to remove iron and manganese.

"While chlorine disinfects the water, we also use ultra-violet light dosing units to provide additional disinfection. This multi-barrier treatment process means we will be producing crystal-clear water of the highest quality," Perera said.

The bores and old treatment plant, which Watercare inherited when the Super City was formed in 2010, had been out of service since 2013. The old plant, built in the 1970s lacked processes to remove iron and manganese and was not up to standard.

By Christmas, Watercare plans to have an extra 40MLD through expansion of existing treatment plants and new ones.

This includes bringing the mothballed Hays Creek dam in Papakura back into service at a cost of $57m to provide 6MLD and expanding the Onehunga treatment plant by 4MLD.

In August, the Waikato treatment plant was expanded by 25MLD, bringing the daily allowable limit to 175MLD.

Bridge said the extra 40MLD is the equivalent of two Waitākere dams, or enough water for 130,000 people.

"This extra water, combined with continued savings from our water-conscious customers, is why we are confident we will get through summer without the need for more severe restrictions."