Details of a comprehensive strategy have yet to be nailed down, but work is under way already to explore how it might be implemented.
Options over the next century may include managing retreat from some areas, creating wetlands to facilitate urban regeneration and deploying engineering solutions, such as water pumps.
The South Dunedin Future programme aims to set up the area to adapt to climate change and an update is to be discussed by committees of the Otago Regional Council today and the Dunedin City Council next week.
The report disclosed work had started "in parallel" to the South Dunedin Future strategy work, to enable immediate implementation from 2026.
Report author Jonathan Rowe suggested the reach of change over the next century might need to be substantial.
If all 6500 properties in the area needed to change their land use, this would have to happen at a rate of 65 properties a year, he said.
"Such a rate of change is yet to be confirmed, so is indicative at this stage; though possible, given anticipated changes in sea-level rise, groundwater levels and rainfall."
It was important to start thinking about "how various adaptation options could be implemented, and to commence preparations", particularly if long lead-in times were involved.
It was obvious land use change in some form would be needed over the next century, "be that through hard infrastructure protections like pumps, pipes and sea walls, accommodation of hazards through nature-based solutions like open water courses, parks and wetlands or through retreating or relocating to move people and property out of harm’s way", he said.
A contract for South Dunedin Future consultancy work in the next three years by WSP, Beca and Tonkin + Taylor is worth more than $1.9 million and is funded by the two councils and central government grants.
Among the challenges for South Dunedin are its lack of a natural water course and the extent to which it is covered in asphalt and buildings, providing little opportunity for water to seep into the ground and making the area more vulnerable to storms caused by climate change.
"The objective of the programme is essentially to find a balance between people, water and space, making South Dunedin a safer and better place to live, work and play, while maintaining and creating more space for water," Mr Rowe said in his report.
In communications material for the programme, it says "water coming in has nowhere to go, and South Dunedin’s infrastructure struggles to cope with it".
"We need to work out how to adapt and allow for water, yet still have space for people and the things that matter."
The report refers to reframing issues to support "the shift away from a deficit-focused, binary approach where South Dunedin must be protected from climate change at all costs until everyone has to leave".
The shift in emphasis is towards "an opportunity-focused, dynamic approach where South Dunedin’s climate change-related challenges are logically assessed, quantified and adaptation options developed that not only manage risks and make South Dunedin safer, but also support activities ... that make South Dunedin a better place to live".
It is expected technical work will lead to a selection of adaptation options for the councils and community to consider, and there will then be more technical work before a preferred set of options is settled on.
