Auckland's water supply in doubt following dispute over Waikato River water usage

The long-term future of Auckland's water supply is in doubt as the city's drought escalates a bitter dispute over the Waikato River. 

Auckland Council's Watercare is planning to use the river to meet the next thirty years of Auckland's population growth, but local iwi and the Waikato Regional Council don't want that to happen.

It means Auckland may have to look elsewhere for its water supply, and that could be costly.

The once-in-a-generation drought has unveiled some interesting things - like old railway tunnels - and some concerning things - like the tense disagreement over whether Auckland can continue taking water from the Waikato River to supply its growing population.

Chairperson of Waikato-Tainui - the tangata whenua of Waikato - Rukumoana Schaafhausen says new solutions need to be created.

"We cannot keep applying the same band-aid solutions to our water shortage problems - this isn't new for Auckland," she says.

Waikato Regional Council chairperson Russ Rimmington says the Waikato River is their asset.

"It's our taonga, and we're not going to satisfy their demands just because of their [Watercare's] incompetence," he says.

Watercare takes more than 160 million litres a day from the Waikato River, and its plan to meet population growth is to just take more - almost 200 million litres more every day by 2050.

If that happened, water supply would be the biggest drain on the Waikato River. It's currently a close second, at 34 percent, to agriculture, which uses 39 percent of the river's supply.

"The river is under stress and it cannot continue to be this way. So we have to do our role as the kaitiaki and advocate for the awa to ensure its protection," Schaafhausen says.

Auckland may also be forced to look elsewhere because of climate change, and because, according to focus groups, residents hate water restrictions.

Watercare CEO Raveen Jaduram says there may be disparities between what residents want and what it believes are the best options for water supply.

"The sentiment is, it seems, please run a water system where we don't have to have restrictions, and what I am saying is that is possible, but that is not the system we have," he says.

A completely drought-proof system would require diversified sources, including dams, rivers and recycled wastewater at a cost of hundreds of millions, if not billions, of dollars.

Jaduram says no one in the world does that due to the costs.

"[It's] because of money. And also, most of the time that infrastructure, that investment, would be sitting idle."

One option that could provide much of Auckland's future water needs is desalination - taking the salt out of seawater.

Two sites have been identified - Long Bay on north Auckland's east coast, and Muriwai on the west.

But desalination would cost about twice as much as taking water from the Waikato River and use about 10-times more energy than Auckland's entire water supply system uses currently.

Jaduram says he'd prefer recycled wastewater.

"From an environmental point of view, it's a closed-loop. Desalination is very expensive, from all points of view, not just money, environment and everything else."

Boiled down, that's what the cost of water is all about - it's both environmental and monetary.

Watercare says the drought is illustrating it's time for Aucklanders to decide what they want to pay per thousand litres of water.

"If people are willing to pay $1.50 today for water, and they had to pay $2 or $2.25 for a higher resilience, they might say yes, and I think that's the conversation we need to have with them," Jaduram says.

All to ensure water keeps flowing out of Auckland's taps without increasingly relying on the Waikato River.