Save Ocean Beach

A public hearing next month will help decide what to do about erosion problems threatening Dunedin's Middle Beach.

The Dunedin City Council has been investigating the problems, and what to do about them, since severe storms in 2007 first highlighted the threat of erosion to Kettle Park and other facilities in the area.

That resulted in a draft Ocean Beach management plan prepared by consultant Tonkin and Taylor last year, covering a 4km area stretching from St Clair to Lawyers Head.

The draft plan recommended continuing the council's holding pattern of monitoring and sand-replenishment work - put in place after the 2007 storms - in the meantime.

However, the report also canvassed 13 longer-term options and recommended a managed retreat from Middle Beach and Kettle Park, or construction of an inland buried backstop wall to protect the area over the next 10 to 50 years, at an initial estimated cost of between $8 million and $19 million.

Yesterday, council community and recreation services manager Mick Reece said public consultation on the draft plan had prompted 17 submissions, including input from the Department of Conservation and individuals.

About half supported the draft plan's recommendations, while the rest had mixed views, he said.

A public hearing, set down for February 21 to 23, would be held to help determine a way forward, Mr Reece said.

chris.morris@odt.co.nz

Dunedin City Council staff yesterday confirmed a clay cap stretching about 150m along the top of dunes at Middle Beach had been removed by contractors, amid fears it was being undermined by waves.

Parts of the cap had already fallen away, leaving plant roots exposed and the remaining cap at risk of collapsing on to the beach below, council parks manager Lisa Wheeler said.

Instead, the cap - up to 1m deep in places - and vegetation in the area was removed by council contractors last month, leaving a flat shelf, she said.

The clay was then replaced with about 7000cu m of sand dredged from Otago Harbour, to restore some of the top of the dunes, Mrs Wheeler said.

"When we took the clay capping off, it was just a flat shelf. We've actually brought the sand back on to try and build the dune back up again.

"It was quite significant [work]," she said.

Otago Regional Council consents required the city council to collect any clay falling on to beach, to prevent it being washed into the marine environment, she said.

The work was undertaken as a "precautionary" measure to avoid that, at a cost of $70,000, but also to ensure public safety for beach-goers, she said.

Public access to the dunes was already restricted, with the area above fenced off since it was discovered the dunes were contaminated by material from a historic landfill located under nearby Kettle Park.

However, plants left leaning over after parts of the cap collapsed were adding to the pressure on the shelf, Mrs Wheeler said.

"Some of it had [collapsed], and there were big cracks where even the pressure of just someone standing on it was moving some other areas of it.

"You just need another little bit of imbalance and it all would have just gone."

Council community and recreation services manager Mick Reece said the clay had been placed on top of the dunes "years ago" - although the exact date was not known - to help promote plant growth.

Adding the clay was "not a good move, as we now know", and would have had to be removed regardless of what decisions were made about the long-term future of Middle Beach.

"As the face of the dune was tested in any way by the weather, you have this great big pie crust on the top that if it was undercut at all, the whole thing collapsed, like slabs of clay down on to the beach.

"Whatever happens in the future ... that clay had to go anyway."

chris.morris@odt.co.nz