An 80-metre concrete wall is being built on Princess Bay to save the road above.
Wellington City Council plans to start the $650,000 project next month, meaning access to the South Coast, Wellington beach will be restricted, while the coastal drive above will be reduced to a single lane at times during the six-month build.
Machinery will work on the beach, meaning some of the sand dunes and vegetation on the beach will be excavated.
Princess Bay lies between Lyall and Houghton bays.
Catching the last of the day's sun, it is a popular spot for beach goers, especially in summer.
''While we would prefer to retain as much of the vegetation and sand dune as we can, this is not possible if we are to secure the footpath and road above the beach and retain usable beach space,'' council city networks manager Stavros Michael said.
''We will endeavour to replant and landscape the beach along the bottom edge of the wall, where the concrete wall meets the rock support.''
The work was needed because of damage done in storms last year combined with future sea-level rises and more damaging storms expected with climate change.
One section of the footpath beside the road above the beach collapsed in February last year and more of the pathway was damaged in the severe southerly that hit Wellington last June.
All up, 80m off footpath had been affected.
This is where the new wall, built to stop further erosion that would eventually destroy the road, would be built.
''We've looked at various options and our preferred solution is to construct a concrete retaining wall with a smaller rock revetment to support the wall at its base.
"This design will encroach only one or two metres on the beach. It will also be strong enough to add a widened suspended path for pedestrians and cyclists in the future."
The council expected most of the $650,000 cost would be recouped through NZTA subsidies and from the council's self insurance fund.
Work is expected to be finished in mid-October.
- The Dominion Post
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