Local Focus: Big tractor saves little birds

It's one of the biggest tractors in the region and it ploughs year-round, but nothing ever gets planted.

That's because the eight-wheeled John Deere behemoth is part of Hawke's Bay Regional Council's flood control system.

It is used to rake and plough gravel in the region's riverbeds so the gravel can be freed up to easily wash downstream once water levels rise, preventing buildup of the riverbed so floods are less likely.

Hawke's Bay Regional Council river schemes team leader Antony Rewcastle said the ploughing helped maintained a flood channel for our rivers along with stop banks and tree plantings.

'Where it builds up and there's a hard armouring layer, we get the tractor to go through and rip it - soften it," he said.

"The idea is that the floods come through and move that gravel as part of the natural process."

The big tractor is also good for native-bird nesting sites, including the black-billed gull - tarāpuka - which is the world's most endangered gull.

It nests inland on braided riverbeds where the ploughing provides a habitat free of introduced weeds, which can offer cover to predators.

"We've actually had some really good reports back from ecologists recently looking at the benefits to the nesting birds they see," Rewcastle said.

"That's their native habitat and they've adapted to those open conditions.

"And now we're getting a lot of exotic waves coming in.

"It's affecting them and closing up that area. So that seems to be compatible for a number of reasons."

Loosening up the gravel to wash downstream helps another important part of the Hawke's Bay Regional Council's flood-control schemes - feeding gravel extraction sites.

When there's too much gravel the riverbed rises, making flooding more likely.

River gravel is a valuable resource for construction projects, so the regional council's gravel-management programme is a win-win for both industry and the environment.

But in Central Hawke's Bay gravel supply far exceeds industry demand, so when central government said it was looking for ways to help the construction industry post-Covid, Hawke's Bay Regional Council presented an $8 million business case to remove gravel for industry.

A job that's a lot easier once the council's big tractor has ploughed through.