Cr Jules Radich has put up a notice of motion for Thursday’s council meeting, arguing a repaired wooden groyne would ‘‘bring back the beach’’ and the cost would be relatively low.
His campaign has historically struggled to find favour at the council and previous advocacy for a trial was defeated.
However, businesses on the Esplanade at St Clair have been united in endorsing the cause and a petition has attracted more than 4600 signatures.
The estimated cost for constructing a timber groyne was $150,000 and consenting costs were expected to be greater than $15,000, Cr Radich said.
Annual maintenance could be $30,000 to $60,000 and monitoring costs about $7500 a year.
Using Aurora Energy hardwood power poles could reduce the cost, he said.
Cr Radich is standing for the Dunedin mayoralty this year and is leading a campaign ticket called Team Dunedin.
The beach has again been battered this winter and just one of the poles that formed part of the loose-planked groyne remains standing.
In material accompanying his notice, Cr Radich argued community voices were calling strongly for groyne reinstatement.
Barriers against reinstatement were primarily political, rather than a matter of practicality, and previous installations had achieved great success, he said.
The Dunedin City Council adopted a broad plan in February for how the coast from St Clair to St Kilda should be managed.
It focused on philosophical approaches after extensive engagement with the community, rather than pinning down specific techniques.
Cr Radich said at the time he could see how a groyne at St Clair might fit in with the council’s plan.
He argued in material submitted for Thursday’s council meeting that groynes were included in the coastal plan and they would make the coast more resilient.
They would work at St Clair because sand tended to move along the shore in both directions, he said.
Reactive management approaches, such as using geobags, achieved little in the face of erosion and sea-level rise, he said.
‘‘It is time to move from this reactive approach and undertake the easiest, least expensive and only proven St Clair sand-retention mechanism included in the coastal plan.’’
Cr Radich said the petition was by far the greatest community response about anything in the coastal plan engagement.
Sand eroded at St Clair in winter storms and accumulated in summer, he said.
‘‘Groynes simply trap more of the summer sand so that the beach builds up higher than it would without groynes.’’
Some of his arguments, such as that experts agree groynes work well at St Clair, are likely to be challenged at the meeting.
ECoast oceanographer Ed Atkin has said erosion there was largely because of sand moving directly offshore during storms and it was not sustainable to consider a groyne as a long-term solution for episodic erosion.
