Farmers say they are losing land to erosion because of river mismanagement by the Tasman District Council.

In response, iwi and stakeholders will be invited on to a council working group to address river management.

However, it will be too little, too late for farmer Kay Baker of Woodstock, who estimates the Motueka River has carved away about 5 per cent of her land over the past decade.

In the latest flood almost two weeks ago, another three metres or so of her riverside paddocks dropped into the river. She attributes the erosion to the river's course being diverted by the council, allowing a gravel bank to build up on a bend opposite her land.

The erosion left riverside fences dangling in midair and other fences on her riverside block laden with debris, cutting electricity to them, so she could not graze her cattle.

She said that no matter what the council proposed, she would have to fund at least half of the estimated $300,000 to $500,000 to stabilise her property.

"It's so bloody disheartening, because I don't have the money to do anything. I'm supposed to watch my land being washed down the river."

She wants the council to restore the river's path by removing the gravel bank or opening the channel behind it, where the river once flowed, but said she had got nowhere in a decade's worth of appeals and submissions to the council.

She doubted that the working group would solve the situation. Meanwhile, "the gravel bank has grown fifty-fold and my erosion is proceeding faster".

Landowners Robbie Reynolds, David McGaveston and Bruce Taylor, who also live near the Motueka River, told the council's engineering services committee last week that some of the river's growing gravel beaches should be removed.

"This would allow the water to go somewhere when we get extra volumes," said Mr Taylor.

He said it was frustrating that the council had been talking about gravel management in its rivers since 2001, with little action.

Mr Reynolds said he lost land in a recent storm, the first damage he had experienced for 20 years.

The "experiment" the council was running in not removing gravel was failing to protect landowners, and the river was now starting to "zig-zag" from bank to bank, he said.

Mr McGaveston said landowners paid huge river rates to have rivers managed and their land protected. "The way rivers are being managed is totally unacceptable."

However, Mapua landowner Devin Gallagher spoke in favour of the current consents system. He said the council had to make sure it was not shooting itself in the foot before altering the consents system.

In his report to the committee, transportation manager Gary Clark acknowledged that the council had been under pressure to remove gravel and had been accused of not protecting land.

But managing a whole river system did not simply mean removing gravel, he said. Gravel removal affected water quality, erosion and flood control, and while some reaches showed a surplus of gravel, those beaches were mobile.

The amount of gravel taken from the Waimea, Motueka and Takaka rivers over 40 years exceeded the amount entering the system, he said.

For example, members of the public had said the gravel beaches on the river's edge near the Motueka River Bridge had never been higher, but a cross-section under the bridge showed the riverbed had degraded and there was 300 square metres more water space there now than in the 1950s. The buildup on the river's edge was mainly silt.

Deputy Mayor Tim King said the current system was "long-winded, somewhat complicated and comes up with outcomes that are difficult for people to understand and hard to implement".

He said council regulations around river gravel had failed to change with the rivers and were due for an update.

- © Fairfax NZ News