The myth of South Dunedin going underwater in the next 100 years is just that, a myth. One that a scientist, community leaders and councils have tried to bust with limited success. So why are people still convinced? Sinead Gill reports.
The news article is available HERE.
When it rains in South Dunedin, it’s not just flooding people are concerned about, but what the flooding represents.
Much of the community, made up of multiple suburbs, was built on swampy terrain, now called “the Flat”. It is infamous for having the most homes 50cm or less above sea level in the whole country – more than Auckland, Wellington and Christchurch combined, according to a 2015 report.
Website Seawise tracks sea level rises and vertical land movements in New Zealand. Dr Simon Cox, a principal scientist at GNS Science, based in Dunedin, said if levels continued to rise at the current rate, parts of South Dunedin would be at or below sea level by 2050. Some 2700 homes would be at or below by 2100.
That speed could change depending on carbon dioxide levels, but he said the forecast “ranges from slightly bad to really bad”.
Yet, being at or below sea level didn’t mean homes were uninhabitable or inevitably going to be underwater. Some Dunedin homes were already below sea level, but protected by dunes.
It was homes on the flat, surrounded by the hilly suburbs of Musselburgh Rise and St Clair, which bore the brunt of the $28 million worth of damage suffered in the significant 2015 floods. Some locals reported that their insurance premiums rose afterwards, and a local real estate agent said the South Dunedin market slowed significantly.
At the time, the Dunedin City Council claimed the infrastructure in the area had been well maintained, and raised concern that South Dunedin was an increasingly risky place to live.
Later, failings by council contractors to maintain infrastructure drains was uncovered, and their role in the flooding deemed significant. But the damage to South Dunedin’s reputation had been done.
In the years following, Cox would begin working with the Otago Regional and city councils to figure out just how dire things could get.
The more is understood about the area, the less dire South Dunedin’s future appears, but the pessimism is persistent.
Cox described researching South Dunedin as like “a sword fight with an enemy in a dark room, without knowing what the enemy looks like”.
Groundwater monitoring had only begun in 2010, at just a couple of sites. In 2019, 20 more monitoring sites were introduced.
Cox, who had a background working on land in post-quake Christchurch, said while the number of unknowns had fostered fear, the more testing they did, the clearer the picture became and the less threatening it all looked.
The myths began to be busted. Was there any basis to anecdotes that backyards turned into shallow pools? Cox said only a few patches got more than 2cm of water during heavy rainfalls.
The closer to sea level your home was, were you more likely to get wet feet? Cox said existing man-made preventative measures, like dunes, were already proven to be effective.
Could South Dunedin sink into the old marsh if there was an earthquake? Cox said if there was a substantial amount of sand present it would have been a concern – the community is flanked by beaches and the harbour – but in reality it was just built on a lot of mud.
“Generally speaking… mud gets stiff when it shakes. It would take a very strong shake [to liquify].”
But despite what the scientists were finding, there wasn’t a lot of co-ordination with other groups. Cox said the regional council had been “brilliant”, but public and private works, community groups and business owners were all working on the South Dunedin question separately. It made it harder to plan for the future.
“It never ceases to amaze me how complicated it is to have people talking together,” Cox said.
Eleanor Doig thought the same thing. In 2016, she saw the council had organised a community meeting, so she turned up.
“The room was full of people who provide services to South Dunedin, talking about things they were doing. I was thinking, ‘I didn’t know that.’
“There was a need for some sort of connecting device.”
In 2019, the South Dunedin Community Network became official, with Doig as the chairperson, and council funding for a staff member.
Doig said while locals loved the community and were increasingly understanding that not all hope was lost, it was an uphill battle trying to spread that optimism elsewhere.
“Part of what happened in 2015 was the mayor at the time [Dave Cull] made a comment under great pressure. He talked about managed retreat … People immediately interpreted that as everyone is going to have to leave, [South Dunedin] is just going to be sea.”
But she was sure that image was changing, in large thanks to Cox and the South Dunedin Future team – a group of people from the ORC and DCC – who presented an extensive proposal to each council in July, suggesting ways in which groups could work together and some climate change adaptations South Dunedin could explore.
“Change is inevitable … The community is vulnerable to socio-economic problems, but it’s a feisty community and I have faith [the change] will be socially just,” Doig said.
Doig said the council’s willingness to talk to community groups directly, rather than wait for groups to approach the council, ensured everyone could be heard.
“It’s not just a traditional consultation method. Because of that, the community is beginning to trust them,” she said.
She was determined that any future plan would include sustainable housing, especially so that if tenants have to leave their seaside homes there is somewhere for them to go.
Doig said people who lived in South Dunedin loved living there, but it was difficult getting outsiders to understand how much opportunity there was, and that it was somewhere worth investing in.
“People may fear the worst … they’re afraid of flooding. Thinking of the worst-case scenario is basic human instinct.”
But change was not just on the horizon, but on their doorstep. The Hillside rail workshop – which in its heyday hired over 1000 people, but closed in 2012 – got an $85m investment in 2021 for a wagon assembly facility.
More than 100 people were expected to be working there next year.
Also in 2021, the community network joined a five-year programme with the Department of Internal Affairs, where they could pitch community-led projects and tap into a $4 million fund.
“It’s a fabulous thing that a catastrophe like the flood is the thing that empowers change, but that’s how life happened. We went from being ignored… now there is all this opportunity.”
While no project had been pitched yet – volunteers were still assembling an in-depth report of what South Dunedin looked like and who lived there – the community would be asked later this year what they wanted to see.
At a council level, there was a South Dunedin Future work programme, created jointly by ORC and DCC staff and approved in July by both councils.
The programme was a plan to make a plan, not committing to any particular solution, but putting in writing what individual groups have been saying for years – they need to work together.
No solution was off the table, but some discussed by council in meetings and in the programme proposal included increasing water infrastructure capacity, creating wetlands, and possibly some managed retreat.
Cox said while there was a risk that water could spill out from the harbour or beach, countries like the Netherlands proved rising sea levels could be managed.
“Two thirds of [the Netherlands] is below sea level. The logical assumption is that the country shouldn’t exist, but they do because of the dyke system… we’re not actually all that different. The main difference is we [South Dunedin] have a relatively small rating base.
“By the time sea levels rise [to levels of concern], there will be pressure on big cities all around the globe. South Dunedin would look like an attractive piece of land in comparison.”
Cox stressed the importance of local knowledge in coming up with solutions, because locals best knew the land and where water pooling was an issue. He said the ORC had done a “brilliant” job in supporting research and local solutions.
He was concerned that if a solution was left up to central government, it would base solutions on things like elevation levels, which was oversimplifying the matter.
“The message that Dunedin is doomed comes from that national model,” he said.
One option referenced in the South Dunedin Future programme is to create blue parks – clearing land for the purpose of capturing rain water running down from the hills, giving it a place to go that isn’t residents’ backyards, such as a wetland.
Cox said for it to work, they’d need a large surface area, and space for infrastructure to drain it. Ideally it would be created on land which is already being used as green space, such as Tonga and Bathgate parks, so that new land didn’t need to be cleared.
The former Forbury Park race track, near St Clair, could also be bought and used for this purpose, though developers were also keen to turn it into housing. Liz Bishop, general manager for Harness Racing NZ, which owns Forbury Park, said the site was still being valued and not yet on the market.
“It would take a lot of effort to not make it a swamp … careful engineering,” Cox said.
“But it could be superb.”
Doig thought as well as providing a practical solution, more natural spaces would enhance the beauty of South Dunedin, potentially offering more parks, picnic areas and walking tracks when dry.
“My 106-year-old aunt wants canals like in Venice,” she said.
