Hanging tough to secure Shore cliff

The cliffs are affected by tidal erosion, wind and rain. Photo / Brett Phibbs

Abseilers work to protect exclusive seaside property, which lies above coastal walkway, from erosion

Elaborate anti-erosion work is being done on an exclusive North Shore beach cliff-face, involving weeks of work by specialist abseilers.

The cliff beneath Steve Barrett's house at 84a Vauxhall Rd above Cheltenham Beach is being stabilised, but he said that was not because of any collapses or rock falls.

"We cleaned up all the old rock and loose rock off the cliff," he said of the work which has left two pohutukawa perched on the edge, 12m above the sea at the northern end of the beach.

Mr Barrett said he bought the seaside property a few months ago. "I bought the land and didn't want to lose any of it."

His 1935 weatherboard house will be re-piled, said Mr Barrett, a director of specialist builder Urban House.

Chris Darby, a new North Shore city councillor, said that end of the beach was part of the Te Araroa trail's low-tide walkway and coastal erosion was a concern.

In the 17 years he had lived at Stanley Bay, parts of the coastal cliffs had collapsed periodically.

Simon Sheehan of specialist repairer CLL (formerly Contract Landscapes) which is working at 84a Vauxhall Rd, said the cliffs were affected by tidal erosion, wind and rain.

A truckload of big rocks had been removed, and the area had been fenced off.

Four specialist abseilers were working daily off long ropes, hanging above the water to repair the vertical face of Waitemata sandstone and Parnell grits.

Now, 36 horizontal 6m deep soil anchor rods had been driven into the face and nine rods had been inserted from above, Mr Sheehan said.

A specialist light-weight drilling rig, powered from a digger on the property above, was used and the drill can be handled by the abseilers, Mr Sheehan said.

"We started three weeks ago and we've just about finished all the drilling," Mr Sheehan said.

A cover, which resembles extremely strong chicken mesh, with fibreglass matting, will soon be applied to the cliff face, stretched over stainless steel wires.

Then, planting of native flora would begin.

Vetiver, a tough natural non-invasive plant with a deep penetrating fibrous root structure, was particularly suitable on such jobs as seven-eighths grew underground, Mr Sheehan said.

Mr Darby said storm water discharge and pohutukawa pruning could endanger cliff edges and called for more information for land owners about anti-erosion measures. He cited the death of a woman in 2011 after a fatal rockfall at Rothesay Bay, although storm water drain runoff was not blamed for that death.

Mr Darby predicted further Auckland cliff collapses.

"All the indications are that we are going to be subject to more severe weather events, particularly north-easterlies.

"The council needs to educate people on how they can take care of their land if they're coastal owners."