Millions for Westport airport seawall that will 'inevitably fail'

Friday, 14 June 2019

Westport airport and Carters Beach has lost about 60m of land to the sea in the past 10 years.

A $2 million Government funded seawall to protect Westport Airport will 'inevitably fail'.

The Government announced on Thursday it would invest $2.074m to repair the West Coast airport's seawall after it was damaged by ex-Cyclone Fehi in 2018.

Carters Beach Domain, near Westport, inundated with floodwater in February 2018.

About 300 metres of the 700m seawall collapsed, leaving only 58m of clearway on one side of the runway. The Carters Beach area has lost about 60m of land to the sea in the last 10 years.

Climate Sigma managing director Belinda Storey, who is doing a PhD at Victoria on insurance, property and infrastructure under climate change, said the airport would need to be moved inland eventually.

Erosion at Carters Beach, near Westport Airport.

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Seawalls did not provide permanent protection against the sea, she said.

'Any decision like that needs a business case that assesses how long that investment will provide a level of defence for. It should include ongoing maintenance costs.

'Any sea wall will come under increasing pressure because of increasing sea levels and increasing storm intensity.

'Whatever height they build that sea wall, in time it will inevitably fail,' she said.

Buller mayor Garry Howard said the council acknowledged the seawall had a limited life expectancy.

'It may hold for 10 years. Eventually we have to have a plan not just for the airport but for other coastal residential areas in the Buller district. This money is intended to buy us some time to look at longer-term solutions,' he said.

He estimated moving the airport would cost 'many millions'.

Carters Beach resident Lockey Mundy, a former pilot, said he welcomed the Government funding.

The existing rockwall had provided excellent protection for the airport until the 'freakish once-in-a-lifetime storm surge' created by ex-Cyclone Fehi.

He had lost about 50m of land in front of his Carters Beach house since moving there 10 years ago.

The West Coast Regional Council recently surveyed Carters Beach residents about paying for sea protection measures that would run alongside the airport rockwall.

Mundy said he was in favour of the council's proposal to build a $144,000 gravel bund. An estimated $2m for a rock wall was rejected by the residents, but many wanted to build a cheaper sand bund themselves.

The council's annual plan, which has been out for public consultation, proposed a new special rating district for Carters Beach to pay for the 'sacrificial bunds'. It would cost each ratepayer more than $130 per $100,000 capital value per year for the next five years.

Council chairman Andrew Robb said seawalls and bunds were only short-term solutions.

'We are careful with community expectations. We tell them you can spend all this money and it may not have a very long lifespan and you will have to look at other options. Many communities around New Zealand will have to face up to it that as sea levels rise they are going to have to move,' he said.

The Minister for Regional Economic Development has been approached for comment.