New seal could ease cost of gravel roads

South Wairarapa District Council spends over a million dollars a year maintaining its sealed road network.

A cheaper alternative for sealing dusty gravel roads could soften the blow to South Wairarapa ratepayers' wallets.

The Otta sealing technique, which originated from Otta, Norway, could be the most cost-effective way for South Wairarapa District Council to seal roads in the future.

At a council meeting on Wednesday, chief executive Paul Crimp said they were taking a serious look at using it.

"NZTA have done some research on this and it may be a solution for parts of our roading network, it's significantly cheaper than a full seal."

The council spends over a million dollars a year maintaining its sealed road network and it can cost over $100,000 per kilometre to seal a 4.5-metre-wide unsealed road.

In broad terms, for every kilometre of road sealed outside of its budget, rates increase 1 per cent per year.

Despite Prime Minister John Key recently announcing a $212 million roading upgrade package, funded by the sale of state-owned assets, none of it will go towards Wairarapa roads.

It also wouldn't change the NZTA's high threshold for road sealing subsidies.

Mr Crimp said the Otta seal was much like regular seal except it was cheaper.

The benefits were dust suppression and it was waterproof, he said.

"The key benefit is really dust suppression, our main problem."

Dust from gravel roads can affect crops and animal production, and many South Wairarapa wineries and lifestyle block residents have made complaints to the council.

"I'm hoping that we can use it, especially on the urban fringes, the lifestyle type areas," said Mr Crimp.

He said it was not effective on inclines so it would suit South Wairarapa's flat roads.

The council could use a combination of regular and Otta seal, he said. Otta seal has a life cycle of 10 to 12 years, slightly less than regular seal at 15 to 17 years. But it required less maintenance, according to research.