In with the bulldozers, out with the gravel - flood-hit farmers want change in river management

Flood-hit South Wairarapa farmer Rod Sutherland wants out.

The fifth-generation farmer has been running the Pirinoa land for more than 20 years, but told RNZ the past one had been particularly challenging, with back-to-back storms causing widespread flooding.

He is among locals nearing their wits' end after rivers once again burst their banks in the region, submerging farmland and destroying roads at the weekend.

More than 450 homes south of the Tūranganui Bridge - isolated since a washout on Saturday morning - were reconnected on Tuesday afternoon.

Residents say a lack of river management is to blame and they are pointing the finger at the Greater Wellington Regional Council [GWRC].

The regional council said a thorough review of its more than 50-year-old flood management scheme - the Lower Wairarapa Valley Development Scheme - was underway and that it was working with the South Wairarapa District Council on solutions for river gravel extraction.

'I want to sell'

It is the third time this year that the Tauanui River bordering Sutherland's farm has burst its banks.

"I'm glad my father's not around to see where it's gone. Maybe he could see something back in the day, he told me to sell up and move away from here, 'That river will break your heart,' those were his exact words.

"I didn't think it would get to the point where they would just stop managing the river."

The farmer said nothing would have stop the flooding from the huge amount of rainfall in February, but he believed the damage and stress caused by the past two storms could have been avoided had gravel been more regularly pulled from the river.

Sutherland - who recently stepped down from the advisory committee to the lower Wairarapa Valley scheme - said a bulldozer shifted gravel in his section of the river for the first time in 17 years last week.

"Just because it's got that bad, the metal is now at the height of the bank and the land is 3m below. I can stand in the middle of the riverbed and look 3m down onto my land now. So I've got no protection at all."

Sutherland said the work was not enough to stop the weekend's floodwaters, which have swept across half his land - the risk of which had forced him to convert lower stock-run paddocks to arable crops in recent years.

"I have about four or five different weather apps on my phone that I monitor all the time. I'm just waiting for a southerly system to come in now and I just can't leave the property. I've got to be around, I run out of room to put animals," he said.

"I'm at the point now where I want to sell. This farm's become a bit of a burden to me and a bit of a trap."

Sutherland said balance was lacking between environmental protection and flood mitigation, and he felt the regional council had to change its approach.

"You need to have the environmental side of it, but you need to be able to protect the person paying the [rates] bill at the same time."

He said more gravel extraction was needed immediately across the region's waterways and proposed a long-term solution that saw Greater Wellington buy-up land bordering the river for the sole purpose of flood spillover.

A perceived lack of river management in the Tūranganui River has also been blamed for raging floodwaters that knocked out Tūranganui Bridge for the second time in four months.

Farmer Ken Aburn said although the rainfall was not as intense as what landed in February, he was not surprised to see the bridge go.

"We got a lot more localised rain. The main problem is there's too much gravel in the river, so the water's got nowhere to go."

Lake Ferry resident and farmer Nicola Warren said the gravel build-up was demoralising.

"It's destroying the rivers, it's destroying the farms, and it's destroying people's hearts."

Sharon Durrant - a Lake Ferry local who was also part of the community's emergency response - said she could see the river management argument from both sides.

She said the bridge's vulnerability meant she encouraged residents to stock-up on supplies ahead of forecast downpours and any repairs were just a "band-aid".

Ultimately, a new bridge was needed, she said.

"At the end of the day, it's nature's way. Water's going to go where it's going to go. I think we need to accommodate the amount of rain or the amount of water that's flowing through there. That bridge is old."

Mayor calls for help

South Wairarapa mayor Dame Fran Wilde told RNZ's Rural News that she met with Greater Wellington about managing rivers on Monday and would also be talking to farmers.

She said the region was sparsely populated and called on central government to help build new bridges and manage floods.

"We're not big, we're not a big city like Auckland ... but we are doing important work for the whole country. It's important that the rest of the country actually listens.

"It's all very well sitting in front of the television watching 'Country Calendar' once a week, but actually, out there things are happening that are not good for our primary sector and we need to fix it."

GWRC catchment manager for Ruamāhanga Pete Huggins said a new approach was needed for flood protection in South Wairarapa and the council had initiated a thorough review the current scheme.

He said the work would involve sharing flood hazard modelling with the wider community and discussing the current levels of service, noting that the scheme - a system of floodways, barrage gates, river management, and drainage - was more than 50 years old.

"Longer-term there may be changes in how flood hazards are managed."

Huggins said about 3000 cubic metres of gravel was pulled upstream of the Tūranganui River Bridge annually, and some landowners had licences to extract "very low" volumes.

He said commercial extraction was not economic and any increase in extraction would need to be funded by ratepayers.

While gravel build-up could exacerbate flooding, he said the amount of rain in 72 hours was likely too much for any flood protection scheme and said the design of the washed-out bridge was a factor in its failure.

"A small low bridge will act as a dam and constrain flow even if the channel is maintained. 400mm is a lot of rain over... such a short period."

But he agreed that work was needed to maintain the life-line bridge for the communities south of it, which could include changes to the river channel.

"A new approach is needed for flood protection in South Wairarapa and Greater Wellington will be working with mana whenua, farmers who rely on the current scheme, and the wider community to co-design a sustainable catchment strategy here.

"We were already working on solutions for gravel extraction and stockpiling in conjunction with South Wairarapa District Council, and are keen to work with South Wairarapa District Council on options for managing extreme rainfall flooding events at the Tūranganui bridge."