Island Bay seawall

Between 18 November 2015 and July 2016, we repaired, upgraded and strengthened the seawall along the Island Bay foreshore.

Island Bay seawall content

Upgraded seawall

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The huge swells generated by a severe southerly storm that lashed Wellington in June 2013 caused widespread damage along the south coast. This included the collapse of large section of the 340-metre Island Bay seawall opposite Shorland Park. The wall, which was built about 1930, was further damaged by sea surges in 2015.

We have repaired and strengthened the whole wall, not just the storm-damaged parts.

The work was done in sections to minimise the impact on the beach and beach goers. Most of the beach remained accessible as only a small section needed to be cordoned off at a time.

What's been done

The work, which was carried out by Fulton Hogan Ltd, involved:

  • removing the large rocks that were put in place as a temporary measure - these will be used elsewhere on the south coast where erosion is occurring
  • repairing and reusing original sections of wall that had been stored at Shorland Park to help retain the wall’s heritage character
  • realigning the parts of the wall that were on a lean
  • digging out the footpath next to the wall and pouring a new concrete support beam below ground level to make the wall stronger and safer
  • drilling holes and inserting vertical rods to secure the upper part of the wall to the lower part
  • repairs to the sets of stairs that go down to the beach
  • work on the concrete piers next to the stairs
  • recontouring the sand adjacent to the wall and replanting the area beside the Marine Education Centre.

Strengthening work

We drilled 290 holes down into the wall from the top and reinforced the holes with steel bars and concrete. These have securely anchored the top section of the wall – the part you can see – to the lower part of the wall.

We also put in a concrete support beam below ground level on the footpath side (along most of the wall) to provide more support. These measures will help ensure the wall remains upright and is more resilient to high seas and storm surges.

Engineering plans

The following plans show the site layout and how the wall is secured and supported.

Plan of site layout.
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1. Site layout

Plan details: sample wall.
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2. Sample wall detail 1

Plan details: sample wall.

3. Sample wall detail 2

Engineering Plans (828KB PDF)

Timeframe

Work started on Wednesday 18 November 2015 and was completed on schedule in early July 2016. 

Photo gallery

Check out the photos of the storm damage and the history of Island Bay waterfront.

 

More information

Faiz Tawfeek
Team Leader, Structures

Phone (04) 499 4444
Email faiz.tawfeek@wcc.govt.nz