Alden Williams/Stuff
An offshore structure remains a possibility to help protect against erosion and the impact of climate change at Dunedin’s St Clair beach.
Dunedin’s coastline could be protected from erosion in the future by new sand dunes, removing contaminated material and even building an offshore structure to protect it from waves.
The ideas were revealed in a new plan to make the region’s shoreline resilient to erosion while lessening the impact of climate change.
The draft St Clair–St Kilda Coastal Plan was released by the Dunedin City Council for public feedback on Monday.
It follows two years of community engagement regarding potential options for St Clair, Middle, and St Kilda beaches, particularly on making the areas resilient to the effects of coastal hazards and climate change.
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The report noted that in the past the approach to managing the Dunedin coast was reactive, with little done to mitigate erosion and sea level rise.
That reactive planning has led to the gradual exposure of hazardous materials along the coast from the dunes at Middle Beach.
The report noted that if nothing was done it would lead to a more eroded beach, which would mean poor access to the beach and a more degraded natural environment.
STUFF
New Zealand beach houses are highly exposed to rising sea levels, but the problem is ignored by many Kiwis. (First published July 2020).
The area’s dunes also form a key coastal defence for the larger area, which includes 10,000 residents.
South Dunedin, the report noted, was built on land reclaimed from a coastal wetland and sits just above sea level – with most of it within 1.5 metres of high tide.
The area’s high groundwater and the predicted effects of climate change, especially sea level rise, coupled with increased rainfall and storm intensity could combine to increase the risk of severe flooding and drainage problems.
Potential remedies for St Clair include the removal of redundant infrastructure from the sea wall, which includes old stairways and piles, and new dune fencing and planting.
ALDEN WILLIAMS/STUFF/Stuff
St Kilda, in Dunedin, is a low-lying coastal suburb.
In the longer term, an offshore structure remains a possibility, and while that would provide a more sheltered wave climate while reducing sand loss, it would affect the popular surfing spot, the report said.
Short-term plans for Middle Beach include stockpiling sand for dune remediation, as well as removing contaminated material from dunes.
St Kilda Beach did not require substantial management action in the coming years, the report noted, but dune resilience through planting and the control of public access would help.
Dunedin Mayor Aaron Hawkins said: “How the coast is managed in the future ideally needs to align as closely as possible with how people value the space and want to use it.”
Dunedin City Council coastal specialist Tom Simons-Smith said long-term management decisions for the coast would either “hold the line” or accommodate coastal processes and rising seas.
“We will be continuing work to help inform these big decisions but, for now, Middle Beach and management of the historic landfill underneath Kettle Park is a real area of focus as we seek to better understand the risk there and provide clarity on the possible future of the site.”
Feedback on the draft is open until Friday.
