The thirst for growth: Can Hawke's Bay confront the limits of its water use?

Former Hawke's Bay regional councillor Paul Bailey thinks water storage measures such as dams only delay an inevitable water use cap to the region's growth. Photo / Warren Buckland

One New Zealand region is starting to confront the idea that there won't be enough water to go around in future. Can Hawke's Bay continue to grow in spite of it? James Pocock reports.

The absolute limit of Hawke's Bay's water supply is speculative, and wrapped in a heavy cloak of politics.

But population growth is real, and so, too, is climate change, and now the struggle to meet even existing demand for water has been recognised by Hawke's Bay Regional Council.

The council's draft Regional Water Assessment has predicted an annual 32 million cubic metre shortage of water in the region by 2040.

While little context has been provided yet about how that figure was decided, 32 million cubic metres is the equivalent of all water used by municipal supplies in Hawke's Bay annually at present.

The council says even water efficiencies and conservation will not prevent a shortfall of some sort. It's proposing a small-scale dam on a Ngāruroro River tributary, while further south in Central Hawke's Bay, a group of farmers wants larger-scale water storage.

But former regional councillor Paul Bailey says he's concerned that water storage measures only kick the can down the road for future generations to address.

"At the end of the day, building storage dams, you can only do that for so long and then you have got to ask the question 'so what are we going to do next?'"

Ongaonga Stream dried up in the summer of 2020. Climate change means maintaining present levels of water use won't be enough to avert a region-wide shortfall. / NZME

Private company Water Holdings Hawke's Bay purchased the consents for the Ruataniwha dam from the regional council after the project was quashed by the Supreme Court in 2017, and is advocating for the Makaroro Storage Scheme in the same location, which they say could store about 100 million cu m of water.

The regional council's dam investigations could lead to 20 million cu m of storage near the mid-reaches of the Ngaruroro River.

But Bailey says it's time to have the conversation about just how much more we can develop Hawke's Bay, not just agriculturally, but also residentially and commercially.

"We are limited by resource and at the moment we are coming up against a limit around water," Bailey says.

"We've got to be cognisant of the water we have and we have got to be using it more efficiently."

Tom Skerman, Regional Water Security Programme director, said the regional council has been working with local councils, horticulture, agriculture and industry on reducing water demand for decades.

"No one is proposing unlimited growth. The Regional Water Security Programme (RWSP) exists because we are facing constraint. This programme is about building resilience for our environment and our communities," Skerman said.

Tom Skerman, Regional Water Security Programme director, said even with water efficiencies and conservation, the region may struggle to meet existing demand. Photo / Warren Buckland

"The RWSP examines how we manage freshwater quantity in a fully allocated system, which continues to face pressure on demand.

"All in the face of the uncertain impacts of climate change.

"Significant pieces of work developed with our communities, including the Tukituki Plan Change and the more recent Tank Plan Change, provide mechanisms to reduce demand, including reductions in allocations and new water efficiency and conservation standards to be applied to water permit renewals."

He emphasised the Regional Water Security Project is also looking at options the region might have to increase supply, particularly to improve environmental flows during dry conditions.

"Our work shows that even with water efficiencies and conservation, we may even struggle to meet existing demand," he said.

"To ensure water security for our whole community, we need to ensure we are working on both mitigation, such as reduced demand, allocation frameworks, and adaptations, such as slowing the water down through above or below ground water storage and improving farm practices."

Brydon Nisbet, Hawke's Bay Fruitgrowers president, said he thought the physical water take cap could limit potential future growth for growers, although it was still speculative.

"You've got to have water at the key times and if you knew you couldn't, that would definitely hinder potential growth."

He said growers in his association always tried to follow best practice with their water use.

"We get audited with our Good Agricultural Practices audit, a big part of that is our water usage.

"We're pretty conscious of not wasting our water and our growers are really good in that space."

Duncan Abernethy, of I & P Farming based in Hawke's Bay, said there will be a growth limit coming for Hawke's Bay with the finite amount of water in circulation, but when that will be wasn't clear yet.

"When we reach that point, how far away and what that looks like is still debated but in theory, you will reach an ultimate cap even if we use water as efficiently as we can."

"I think where we end up is people taking far more of an intensive look at how they are using that water," Abernethy said.

He said modern water takes by agriculture in the region are not simply about taking the water, but looking at mitigation to impacts on the environment alongside maximising productive output through methods such as river flow augmentation.

"In terms of water use, how we are using it and the environmental effects are absolutely front and centre."