Save Ocean Beach

It says preliminary tests indicate there is no immediate concern about the safety of the rest of the sea wall.

At least one business owner in the area yesterday expressed concern about a lack of information being provided by the council on the status of the wall.

Starfish Cafe co-owner Cushla Dodds said because the holes appeared to be growing and the council had told her nothing, she had checked her insurance policy, just in case. She said she knew other businesses had too.

Business was being affected because people thought they could no longer walk around the Esplanade or bring their dogs there, she said.

People also wanted to know the long-term plans for the seafront. She had not contacted the council, but felt she should not have to.

Next door, florist Carley Jones told Radio New Zealand that each day the drama went on, the more scary it became.

Council roading network engineer Peter Standring said the situation yesterday was that the council expected sinkholes in front of the South Coast Board Riders' Association at the north end of the sea wall would continue to grow in a northerly direction over the next week, as contractors worked in two-hour bursts around tides, to plug gaps underneath the sea wall at that end.

The amount of walkway fill being sucked out through those gaps had already been reduced by remedial action taken since the first hole appeared on Sunday, but material could still disappear until sheet piling along the base of the northern end of the wall was completed, he said.

The sheet piles were being sunk 3m deeper than the foot of the sea wall along the 50m section of wall.

The work was being done in sections and had started around the St Clair Surf Life Saving Club's ramp, where the biggest gaps were. It was expected to take at least another week, because access was limited by the tides.

He said it was anticipated the pits in the walkway would eventually extend along more or less that whole section of the walkway, to the northern end.

However, engineers had indicated the damage would be contained to that area.

A preliminary check by engineers and a ground-penetrating radar had not revealed any voids under the remainder of the wall or walkway along to the salt water pool.

Mr Standring said the priority was to plug the gaps where the beach level had gone below the bottom of the wall.

A more extensive assessment of the rest of the wall would then be made and a long-term response considered once that work was completed.

A portion of the Esplanade walkway along its length and about 3m back from the wall would remain cordoned off until at least then. The cordon still allowed room for foot traffic.

Council operations manager Tony Avery said the council had not approached businesses or residents in the area because there was no concern about the remainder of the wall, although it certainly would if there were any concerns.

He said anyone wanting information could contact the council on 477-4000.

debbie.porteous@odt.co.nz

Advice will also be taken on providing a long-term solution to problems such as the one which caused a section of the Esplanade to be undermined.

While the integrity of the wall was believed to be still intact, the Dunedin City Council would have the entire seawall assessed as a precautionary measure, council roading maintenance engineer Peter Standring said yesterday.

The assessment would be carried out by contract engineers.

The first of several large holes appeared on Sunday behind the seawall in front of the St Clair Surf Life Saving Club and the South Coast Boardriders' Association, after heavy seas and high tides depleted the beach of sand, exposing the toe of the wall.

That allowed waves to flush behind the wall, washing out the backfill, causing the paving above to collapse.

The area from Forbury Rd to the north end of the wall is cordoned off and most access from the Esplanade to St Clair Beach is closed until further notice.

Tracked excavators have been on site since Monday, shifting rocks to protect the bottom of the seawall.

Vertical sheet steel piling is being installed in front of the seawall, on either side of the lifesaving club's ramp, along with cross-bracing under the ramp itself.

Mr Standring said contractors would backfill the area between the seawall piles and the sheet piles with concrete today and tomorrow.

He said much of the beach was at the lowest level staff had seen.

Because tides were so high, the waves had been hitting the sea wall without breaking, putting significant pressure on it. The situation was expected to improve after Tuesday's king tide.

However, it had highlighted the need for a long-term solution which worked with the natural environment, he said.

''This is a natural occurrence and we will be getting expert advice on how to best deal with these challenges in the future.''

He said some St Clair businesses and residents had reported heightened building vibrations this week.

That was ''more than likely'' happening because of the lack of backfill behind the wall at the northern end, which would normally dampen pounding waves.

He emphasised it was important for people to avoid the cordoned-off area while work continued.

There was public access to St Clair Beach via Middle Beach.

Updates on the project are available on the council's website.

-debbie.porteous@odt.co.nz

A further hole has opened up in the Esplanade at St Clair and two holes which appeared yesterday have merged into one larger opening.

The holes in the paved area in front of St Clair Lifesaving Club first appeared yesterday as big swells pounded the coast.

The new hole is on the Lawyers Head side of the surf-lifesaving ramp.

Dunedin city council staff are assessing the situation amid a steady stream of onlookers. 

About 2.30pm yesterday, police and contractors began to cordon off the seaward side of the Esplanade, from the St Clair Lifesaving Club to the car park, as a precaution.

The Esplanade was full of people watching the waves crashing against the sea wall.

One of the holes in the paved area in front of the life-saving club grew from about 1m long to about 4m long and others had also grown in size after the high tide at 4.30pm.

Swells of 2.3m are predicted and tides of similar heights are forecast for next few days.

Life-saving club president Antony Mason said he called the Dunedin City Council and Fire Service after finding the tiled area to be a ''bit spongy underfoot''.

''It got bad real quick. Within an hour there were two holes.''

The news grew worse when he realised the club's ramp to the beach had moved about 20mm and water was going under the ramp's tunnel, he said.

''We've got no access to the beach and the polar plunge is in three weeks.''

He had seen bigger seas and the beach in worse conditions than yesterday.

Dunedin City Council roading engineer Peter Standring inspected the site yesterday afternoon and found a significant ''drop out'' below the tiles.

''If you looked back underneath, the tiles were suspended.''

It was for that reason the Esplanade was cordoned off, he said. While the tiles looked fine on the surface along the rest of the Esplanade, there could be a void opening up underneath.

He believed yesterday's high tides and swells shook the tiles loose but the undermining of the ground had probably occurred over time, as the sea sucked material out from behind the sea wall.

''It's been an ongoing process. It highlights the need to look at everything.''

From his assessment of the site, he did not believe the integrity of the sea wall had been compromised.

Engineers would visit the site today to get a better idea of what was happening, he said.

The holes are the latest problem to beset the Esplanade.

The stairs and ramps to the beach have failed several times, due to what the council believed was a combination of construction and design faults. The high tides also brought surface flooding to Portobello Rd and the streets off Portsmouth Dr late yesterday afternoon.

-rebecca.fox@odt.co.nz