He said the farm was still a “bit of a mess” after the Motueka River it bordered ran through the property, bringing silt, debris and rocks in its trail of destruction.
“We’ve got about 50 hectares that have been completely flattened by the floods, not a fence left,” he said.
“20-odd hectares covered in river rocks, gravel, debris and silt.
“Yeah, it looks more like a riverbed than a farm at the moment.”
McGaveston said a defect was discovered at the stopbank between the farm and the river a couple of years ago, and he had been working with the Tasman District Council to address it.
“[2023] I think it was when we went first went to council and said it needed to be repaired because it was going to come through there, like it has,” he said.
“It was just like an open gate for the whole flood to go straight through there.”
McGaveston said he believed a plan developed with the council was going to progress after their emergency response work, which he supported.
“Actually, they started dropping a bit of rock there the day before the flood, but that was meant to happen a bit earlier in the year, and it didn’t.
“And then the rest of the job was meant to start in July.”
He said he believed the damage on his farm would not have been as bad if the stopbank had held.
“[We’ve] got all the stuff, gravel ... all over our paddocks that needs to come off as well.
“So the job is 10 times worse.”
The Tasman District Council faced the task of maintaining 285km of major rivers.
Efforts to improve flood resilience garnered funding from the Government last year.
Last August, the Government announced $16.5 million in co-funding grants for flood resilience in Nelson and Tasman. That included $6.6m for refurbishing the Lower Motueka River stopbank and $900,000 towards the Peach Island stopbank repair.
David Arseneau, the district council’s team leader for rivers and coastal structures, said it was working collaboratively with McGaveston and neighbour Hinetai Hops on the issue.
Arseneau said several rain events in the past 12-18 months had led to the failure of a “legacy, unconsented private stopbank” that was keeping the river contained.
“It is hard to overstate just how severe this flood event has been for the district, approximately a 100-year flow event, and the scale of this flood needs to be put into perspective with the work that will be done at Dion’s farm,” he said.
“The project will involve establishing a new riverbank line with new willow plantings, anchored trees reclaimed from the current riverbank, and grading to provide more room and capacity for the river to flow through this area.”
Arseanau said that about 5ha of McGaveston’s farm, which was tipped to become a man-made river corridor, were occupied by the river in this flood event.
He said the planned work to plant willow trees to capture flood debris, when mature, will resume as planned, though work was disrupted by the floods.
Massive floods will always affect low-lying floodplains where many in the district farmed, he said.
However, he hoped to reduce the intensity of the damage by “making sure the river has enough room” and by establishing riverside riparian buffers.
“[But] the river channel will only ever be able to contain limited flows before spilling into its floodplain, perhaps a mean annual or two-year flow level, and council does not provide any flood protection service (i.e. through stopbanks) in this area of the Motueka River to contain more significant flows than that.”
McGaveston said he lost no stock, and they were able to find grazing land, but the challenge for feed would come later in winter.
– RNZ