The Waiho River is now severely threatening the viability of the largest Waiho Flat farm in South Westland and others downstream, farmer Neil Frendrup says.
As a result of more than 1400mm of rain during a storm last week, Frendrup says the river has moved again, eating more of his 600ha Franz Dairies property.
A stopbank was extended after the river destroyed the Franz Josef airstrip and much of the farming district in 2019.
Frendrup said the river was now running deep and swift through a significant portion of his most productive land "at a great rate".
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"We've got the river coming around the end of the stopbank and it's going down through 14 of our paddocks."
The affected paddocks were close to the milking shed, with the new channel running "swift" rather than simply being an overflow trickle.
"I shudder at the thought of what's happening to the farmland downstream from us as well," Frendrup said. "There's not really much we can do ... there's such a big quantity of water."
The affected paddocks were the "most productive part of the farm".
Frendrup said the worst might have been avoided if the whole $24 million flood protection scheme, with a further 200-metre extension of the Milton stopbank, had been given the green light. Instead, the Government has put a hold on any works on the south bank of the Waiho.
"The bank extensions would prevent the damage being done."
Having spent thousands of dollars himself on river management, he said there was nothing he could do this time.
Waiho Dairies is one of the largest single suppliers to Westland Milk Products in Hokitika and a significant contributor to the Franz Josef economy.
Peter Dennehy, who has land immediately below Franz Dairies, said he had already spent a lot trying to stop the river erosion.
"Nothing was getting done, and I'm paying my rates as well ... What the hell do you do when you've got no support? It's all very well council coming down and watching the river? We can all do that."
Dennehy said Waiho Flat residents were in limbo over what the Government might decide also needed "an exit strategy too", repeating the words of the regional council's chief executive and her signalled intention to leave.
It cost him $30,000 to $40,000 to get a big bulldozer in every time the river cut in, "and there goes your profit for a year".
Literally throwing money into the river was something a conventional business would never do but the Waiho Flat farmers had no choice.
The rating district had meantime been left to wither.
Dennehy said the regional council could have helped manage the situation meantime through some river training over about a kilometre stretch below the Milton stopbank.
"They don't seem to have the appetite to do it, and it doesn't take much to do ... there's none of this stitch-in-time stuff going on.
"It's a ridiculous way of running it. You can't run a farm or any successful business like that."
Longtime Waiho Flat farmer and member of the rating district Richard Molloy said the promised 200m extension to the existing stopbank would have saved the damage last week.
He noted good work by the regional council to rebuild and raise the stopbank following the 2019 flooding had been money well spent as otherwise, the river would have gone straight back through the Franz Josef airstrip last week, as it did in 2019.
However, the council was still falling "way short of prudent maintenance" of the existing protection.
Last week, council chief executive Heather Mabin acknowledged Waiho Flat landowners needed certainty, after outlining regular attempts to get clarity from officials on the release of the Government money for the original $24m scheme.
"There's some very, understandably, upset Waiho River residents if they do not get stage two," Mabin said.
