Although South Dunedin and coastal communities need to be made aware of the risks of sea level rise, tsunami and groundwater inundation - the ball was now in their city and district councils' hands.
Otago regional councillors this week considered two reports - groundwater modelling into the effect of sea level fluctuations in South Dunedin and community vulnerability to elevated sea levels and tsunami.
Councillors and staff were quick to point out the information in the reports about the risks faced by living in those areas was nothing new to residents.
Cr Louise Croot said the scenarios in the reports regarding South Dunedin showed a "very long-term" approach.
"It needs to be kept in perspective. It won't have an immediate impact - it's a gradual process."
The regional council was being responsible by monitoring the situation in South Dunedin but it had implications for Dunedin City Council and its plans to refurbish its infrastructure.
The city council's sewer network sat on top of the aquifer and cracks and permeable joints in the sewer pipes allowed the entry of groundwater, and as a result the sewers had become a de facto drainage system, a report to the natural resources committee said.
A resulting concern was the impact making these pipes watertight might have on the groundwater level.
Cr Trevor Kempton said what the region did not have on its hands was a "disaster". It was a manageable situation over a 50 to 100-year period.
Chairman Stephen Woodhead said it was a long-term planning issue that was "very difficult to face up to", especially surrounding the question of community sustainability.
The community vulnerability report for coastal areas, based on 2008 data, had already been discussed with the city council and Clutha and Waitaki District Councils.
Mr Woodhead said tsunami and storm surges were in the top three risks Otago's civil defence organisation planned for but like the South Dunedin situation, it raised issues for land use planning.
"In low-lying areas, if you haven't the time to get out, should you be there?"
Building houses on poles was "ridiculous" and set up communities in areas which were not safe, he said.
The regional council needed to keep reminding residents of the dangers and there needed to be some long-term planning around appropriate land to build on, which could mean "drawing a line around some areas" indicating they were not for human habitation, he said.
Cr Duncan Butcher said the regional council's responsibility was to make sure those communities considered the information and put in their council's plans.
Chief executive Graeme Martin said the regional council had responsibilities for civil defence management and the Resource Management Act and would work together with other councils on the issues.
