Temporary water treatment units and a desalination project for seawater are possible as Watercare prepares to spend up to counter Auckland’s historic drought.

Auckland’s water supplier could need to spend up to $180m urgently to find alternative sources of water if insufficient rains fall through winter, worsening the city’s drought.

The spending is signalled in Auckland Council’s emergency Covid-19 recovery budget and would pay to extend treatment for Waikato River water, for ‘modular’ treatment plants at Pukekohe and near an unused source at Papakura plus possible new measures such as desalination of seawater.

Watercare, the council company that runs the water and wastewater systems, has already committed to about $70m of the spending to try to get ahead of a potentially severe drought through next summer. The $180m total is the top end of its contingency in case rains don’t start to re-fill storage lakes in the Hunua and Waitakere ranges.

The storage lakes were on Friday 45 percent full, compared with 43 percent one week earlier, and likely about 41 percent had there been no rain in that period. The early June average is around 75 percent.

Water restrictions and public appeals have seen consumption fall below a Watercare target of 410,000 m3 a day, but to avoid tougher measures next summer the city needs above average rainfall between now and November. The Niwa and Metservice forecasts are for below average rainfall in that time.

Watercare’s chief executive Raveen Jaduram told Newsroom the company had to plan ahead in case the rain stayed away. It had not been able to cut its planned capital spending for the July 1, 2020 – June 30, 2021 financial year as other council agencies had done through the emergency budget.

It had already spent money increasing the treatment capability of the Waikato River source from 150 to 165 megalitres a day and by August, into the next financial year, that would rise to 175 megalitres. On top of that, Watercare was planning modular units at Pukekohe to treat a groundwater source “as quickly as possible” which could initially give 2.5 megalitres, rising to 5 mega litres, into the system.

The Papakura project was to use modular units to treat water in the Hays Creek dam and that would deliver 18 megalitres a day. (Watercare helped build 26 modular units for Christchurch after the 2011 earthquakes). “We have got staff and contractors pretty good at doing this.”

However, none of them can make it rain.

Auckland’s Upper Nihotupu dam, autumn 2020.  Photo: Supplied

“Our problem is only solved by lots of rain. What we’ve allowed for in our budget is us heading towards November. 

“If we feel whatever we have got is not enough then we will bring on additional sources. We don’t know where. We are looking at lots of other things we can do right now,” Jaduram said.

“This whole exercise is finding the raw material. We can build the factories, we just need to find where the raw material is and we need the raw material close to our transportation system [pipes].”

If there continues to be too little rain in the coming weeks, he expected a “drop dead date” when we have to press the button if it [components] is coming from overseas.

One option being considered was seawater desalination. “As a temporary solution, we could bring units here that will desalinate the seawater. The challenge there is desalination needs a lot of energy. Where will the energy come from? Is there an electricity supply available close by to wherever it might be. Where will it be located and how will the desalinated water get to our system?”

Jaduram said the process of desalination did not treat water. “So we still have to treat it.”

But, “it’s on the table. It is a raw water source which is the seawater. We would have to get through all the processes, the permits and consultations.”

A bill introducing emergency changes fast-tracking the Resource Management Act’s consenting processes is expected to be enacted this month. “Anything that comes through that is beneficial to us, we will gratefully receive,” he said.

The extra Watercare spending is likely to impact the council’s overall debt level and thus its capacity to seek money for other commitments.  As well, the company will see its income reduce by $50m next year because of a drop-off in water use during the Covid-19 lockdown and reduced demand caused by the drought. It has shaved its proposed increase in wastewater charges on July 1 from 3.5 percent to 2.5 percent, cutting revenue by just under $3 million.

And Watercare estimates it will lose a further $20m in revenue from an expected slowdown in the completion of new dwellings over the next year, representing about 20 percent of what it receives under Infrastructure Growth Charges.

Tim Murphy is co-editor of Newsroom. He writes about politics, Auckland, and media. Twitter: @tmurphynz

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