However, at least one councillor is sceptical about the value of a programme of work aimed at producing a comprehensive climate change adaptation plan.
The South Dunedin Future programme run by the Dunedin City Council and Otago Regional Council released reports yesterday assessing risk for South Dunedin from natural hazards and unveiling seven options about what might be done in the next 75 years to adapt.
One option was a status-quo approach and Sophie Barker was one Dunedin city councillor who discounted this as unrealistic.
"It’s imperative that we take action on South Dunedin," Cr Barker said.
"No-one wants flooding crises ... the costs are too huge for people, property and the city.
"We have to take all the risks and options into account and come up with the best and most cost-effective solutions we can."
Consultants estimated a status-quo approach could cost about $2 billion over 75 years, but benefits could be worth just $200 million and residual risk was classed as extreme.
Other options contained various mixes of emphasising upgrading pipes and pumps, coastal protection, creation of water courses or storage and retreat from higher-risk areas.
Their benefits were estimated to range between $2.3b and $4.5b.
City councillor Steve Walker said the status quo was not an option.
High-quality research and work had been done to position the city to stay ahead of the climate-change curve, he said.
"The last thing you want to be doing is scrambling with your pants down when the climate crisis in your city goes pear-shaped," Cr Walker said.
The community needed to be brought on a journey with the councils if one of the other six options was to succeed, he said.
However, Otago regional councillor Gary Kelliher wondered if "this massive exercise in uncertainty" provided something of an out for the city council, "rather than just maintaining and upgrading their drainage system".
"All the options seem to be in the billions and all based on climate modelling that is not definite," he said.
The people of South Dunedin would lose out most while the councils "fluff around with big-ticket options and airy-fairy statements like creeks and streams and wetlands".
A 75-year planning window needed concise milestones "or it will just rapidly make the South Dunedin properties near worthless at a time in the near future".
Other regional councillors were much more supportive.
Cr Elliot Weir said the seven options "outline the fork in the road we face as councils and communities".
"The next steps ahead for the South Dunedin Future programme present not just an opportunity to plan for the natural hazards ahead, but also an opportunity to organise our communities for the better of everyone."
Cr Alan Somerville said long-term thinking was essential.
"We want to plan for healthy and safe housing for the people of South Dunedin before an emergency limits all the options — and we don't want anyone making investments that will prove to be wasted in the face of known threats."
Cr Tim Mepham said the seven options spanned possibilities ranging from the status quo to large-scale managed retreat and he felt a decision should land somewhere in the middle.
"A combination of managing water through natural wetlands, canals, engineering solutions and some retreat will make South Dunedin a sought-after urban area, enhancing property values and creating confidence in the future."
City councillor Andrew Whiley said it was accepted change was required.
Property owners and buyers needed to be aware of challenges, he said.
"But at the same time, we also have to play a part and ensure that we minimise flooding events in South Dunedin."
The two councils are due to discuss the contents of the South Dunedin Future reports next week. — Additional reporting Hamish MacLean
