Hawke’s Bay Regional Council seeks approval for groundwater storage trial

The future of Hawke’s Bay’s water storage problems may lie beneath our feet.

With the region in drought for two consecutive summers and any future large-scale water storage options still years away, Hawke’s Bay Regional
The Council requested consents for a new testing option – groundwater storage.

The council proposes to take three million cubic meters from the Waipawa River to filter through an artificial wetland in a shallow aquifer to be pumped into a lower level aquifer in a process called Managed Aquifer Recharge (MAR).

Water storage struggles have continued in recent years after a proposal to build the controversial $ 330 million Ruataniwha Dam above ground in central Hawke’s Bay was blocked by the Supreme Court in 2018, despite nearly $ 20 million in Hawke’s Bay Regional Council spending on approvals and planning.

The council is now seeking permission to advance a three-year trial for MAR, which is part of the Regional Water Security Program (RWSP).

When water levels are high in winter, the water would be piped from the gravel below the river and gravity-fed through two farms to a third farm, where the water would be filtered through an artificial wetland.

Regional water security program director Tom Skerman said he would then pass through a series of “leaky pools” in the shallow aquifer – essentially mimicking how aquifers are naturally recharged.

“What we would expect to see is that the water table rises and remains high enough to protect the ecosystems of downstream rivers, even during dry summers or droughts.”

Traditionally, the deepest aquifer is where most of the water in Central Hawke’s Bay comes from.

Skerman said a second part of the trial would be to test pumping naturally filtered water into the deeper aquifer during the winter months when river levels are high.

“In the summer we will try to recover some of this stored water.”

In partnership with local farmers, the recovered water will be used for a sustainable land use trial to demonstrate new practices in water conservation, cultivation and land use.

It was an important part of building water security in the region, he said.

Skerman said the Tukituki River, which is part of the Tukituki watershed that includes the Waipawa River as a sub-watershed, has been identified as one of New Zealand’s most vulnerable to the impacts of climate change.

It was an example of the global conflict between shrinking freshwater supplies and increasing pressure on the water supply.

“Although water permits for Hawke’s Bay rivers and aquifers have been capped, we still need to build our resilience to climate change by working hard to supplement supply and reduce demand.

“MAR has the potential to make a significant contribution to increasing water security in this area and alleviating pressure on the major aquifers and waterways in Central Hawke’s Bay. If the trial is successful, a network of MAR sites could be strategically located to replenish groundwater. “

The Council has engaged with mana whenua on the MAR trial since the end of last year to ensure that any cultural impact is identified.

The Hui will be held later this month, with marae located near the site to discuss a cultural impact assessment and the potential for a cultural monitoring program.

Federated Farmers Hawke’s Bay President Jim Galloway said it was an important decision and a long delay given the delays since the Ruataniwha Dam was proposed for the first time.

“It’s used a bit in Canterbury and it’s successful there, so it’s not totally new technology. Definitely worth going.”

Without some form of reliable water storage, Central Hawke’s Bay is becoming a “dust bowl,” he said, but with it apples, carrots and other crops would be much easier. to cultivate.

“Anything that can help with the storage and safety of water is great news. The most important thing will be to make sure that we do not contaminate the aquifer.”

Tukituki Water Security Project Chairman Mike Petersen said the proposal was part of a solution to address water security concerns.

“The safety concerns are making sure there is enough water to keep our rivers and people healthy.”

He said MAR would be a welcome addition and understood it to be a try but he was very keen on the outcome.

The Tukituki water security project focused on the needs of the Tukituki watershed, he said.

“It should be finished in the next few weeks.”