Slips can’t be fixed forever
The viability of continuing to remediate coastal erosion-prone sites is being investigated by Auckland Council, as it begins $30 million of work to fix some storm damage.
The council is dealing with 139 sites in need of repair on Community Facilities land across the region, and there were many more slips on top of this, geotechnical and geological practice lead Ross Roberts told Hibiscus and Bays Local Board members in an update on work being carried out in the board’s area.
Most slips occurred in March last year, and recent bad weather caused further coastal damage, Roberts said.
Sites had been prioritised by classifying risks to the council and members of the public, he said.
Ranked at the top were Te Araroa Trail segments Lotus Walk in Browns Bay and Crows Nest Walk in Murrays Bay.
At Lotus Walk, the cliff face had fallen away undermining the cliff top-to-bottom path and, at Crows Nest Path, a section of weathered soil three metres deep was sliding off the top of the cliff.
As part of remedial work designs, long-term viability needed to be seriously considered, Roberts said.
Sites like Crows Nest, where there was evidence of a previous walk five metres out on now nonexistent cliff top, flagged issues of actively retreating cliffs and coastline, Roberts said.
‘‘These paths are going to continue to get damaged, and over time we will get to a point where there is no pubic land left and we are into private land ... and then the options become very limited.’’
Coastal and geotechnical services team manager Paul Klinac said the same thinking on cost and viability was being applied to coastal structures like seawalls and beach access ways.
‘‘We haven’t completed all of that thinking yet. It has been very much, with the most recent storms, get on and fix it and reopen these access ways.’’
But council officers were trying to embed long-term strategies within remedial framework, Klinac said. ‘‘It will get worse over time in many areas, so now is the time to start to prepare.’’
Another high priority slip to be rectified was in the car park at St Anne’s Hall in Browns Bay, where a retaining wall had been undermined, Roberts said.
The slip on Lotus Walk in Browns Bay is one of the trickiest to rectify with heavy civil works and abseiling contractors required.