Council commissioned a report from Jacobs New Zealand Ltd to understand the asset condition of the rock sea wall from Cave Rock to Scarborough.
This review was undertaken as part of our normal operational asset assessment and repairs process.
The report tasks included:
The report found that no urgent or immediate works are required on the sea wall in its current condition, it continues to do the job of protecting the esplanade from erosion and inundation.
We know that, in large storms, seawater can overtop the revetment. However, the water is then contained by the setback wall which separates the promenade from the esplanade. The whole structure (revetment and set-back wall) provides two lines of defence which effectively manage existing sea-level conditions.
The report did find that the wall is below the optimal design for people to walk along the promenade safely in a 1 in 100-year storm. However, upgrading it would be a major project requiring significant investment to maintain access when an alternative walking route (the esplanade) is available during extreme weather. We can manage the risk to pedestrians during extreme storm events by restricting access – as we do with other Council assets in extreme weather (for example, the New Brighton Pier).
To assist Council with its maintenance priorities, the report identifies 19 sites along the wall where repairs are required to increase the durability of the existing structure:
As there are no urgent or immediate works required, and we don’t currently have any funding allocated to this project, we’ll be using the findings of this report to help prepare a multi-year repairs strategy and work programme.