Carterton residents are questioning a new floodplain management plan which they say will protect Greytown from flooding while increasing the effects of flooding on their side of the Waiohine.

At a community consultation meeting with the regional council last Thursday, Carterton property owners affected by the proposed Waiohine Floodplain Management Plan raised concerns about the plan, saying there was no great benefit to Carterton.

The proposed plan, including the construction of a new stopbank on the Greytown side of the Waiohine River, will prevent the river from flooding in Greytown up to a one in 100-year flood.

However, this will increase the effects of flooding to some areas of Carterton in such a flood, with the worst affected area around Matarawa and Gallon Rds.


Speaking after the meeting, Carterton councillor Mike Ashby said a "major issue" with the plan was regional council seemed to expect Carterton ratepayers to pay for installing new stopbanks on their side of the Waiohine River, at a cost of $1.5 to $2 million.

"Not only are we receiving the water, the expectation expressed by the regional council was that the Carterton ratepayers would pay for improving the stopbanks on the Carterton side."

More clarity was also needed on how the plan would affect Greytown ratepayers, Mr Ashby said.

"That causes a bit of anxiety because once you've agreed on these things, it's out of your hands and I can imagine ratepayers later on getting a bit of a fright when the full costs come through."

Mr Ashby said he was frustrated with the consultation process, and although it had improved, GWRC could have "listened to our needs a bit more".

The project is expected to cost around $9 million, and under current policy 50 per cent of the cost will be met by the Wellington region, with the rest to be paid for by locals.

The regional council's general principle for funding the local share is those who benefit, in this case Greytown people, should pay.

Based on current costings for the scheme, this means an increase of $36 per $100,000 rateable value for each urban Greytown ratepayer.

With the current rating split, people owning a $500,000 home in Greytown could face a maximum rates increase of $180 a year.

Speaking after the meeting one resident, who has told been told that the plan means floodwaters could reach as high as 0.7m above his floorboards in the event of a one in 100-year flood, said he was not happy with the proposal.

"There's no benefit to the Carterton side."

"The proposed plan sends the flood water our way while protecting the other side."

His family had spent considerable time and money doing the property up and believed raising the house or putting in a bund, options suggested by the regional council, would significantly decrease its value.

Carterton Councillor Jill Greathead said affected residents felt they had not been "spoken to in the right way".

"They feel like they have been ripped off - they feel as if they haven't been properly consulted with."

There were also "big questions" about how the affected homeowners would be compensated, Mrs Greathead said.

However, GWRC Flood Protection Senior Engineer James Flanagan said a decision on who was paying for what had yet to be made, but Carterton residents might pay an equal share of the local portion of costs associated with the regular river works.

Seven houses would receive additional flood water in the event of a large flood, with most expected to receive a few hundred millimetres of extra water.

It was unfortunate that in protecting Greytown from flooding there would be more water on the Carterton side of the river, Mr Flanagan said.

"Flood water can be moved around the floodplain but it must go somewhere.

"The stopbanking proposed for Greytown includes compromises to minimise the amount of water that is pushed onto the Carterton side of the river."

Public consultation on the plan closes on July 15.