Fight or flight: An old suburb and the sea
South Dunedin is home to the country’s largest low-lying community, with 2700 homes less than 50cm above the high-tide line. As the sea level creeps up, its 13,500 residents are waiting to see whether they have a future, or whether the suburb will be reclaimed by the waves. The answer will reverberate through coastal communities around the country.
By George Driver
If you walk along Dunedin’s Esplanade at high tide during a brisk southerly (and there’s usually a brisk southerly), take heed of the waves below. Ignore them and you’ll probably get wet.
To be fair, it’s a coastline with much to distract the eye. From the Esplanade, there extends a three-kilometre sweep of golden sand that almost looks something like the Gold Coast if you squint, but instead of tower blocks the backdrop is rolling green hills and coastal cliffs.
When the southerly picks up, the sea seethes, a screaming white wall that crashes high up the basalt cliffs at Lawyers Head, and almost engulfs White Island, three kilometres out to sea. In any weather, it has the power to silence a busy mind.
Well, not quite. Behind the dunes lie the homes of more than 13,000 people whose minds are often preoccupied by this beautiful but temperamental neighbour. The stakes are existential. The houses of South Dunedin sit on what was once an estuarine wetland, but more than 150 years ago the outlet to the sea through the sand dunes was filled and the wetland drained and raised to create space in what was the country’s largest and fastest growing centre. (‘South Dunedin’ is commonly used – as it is here – to describe not just the suburb of that name at the base of Otago Harbour but all of the flat area between there and the ocean beaches.)
What remains of the dunes has mostly kept the waves at bay. But wherever you are in South Dunedin, the water is not far away. In most places it sits less than a metre below the streets and homes. When it rains hard, there’s little room left to soak it up so the groundwater level begins to rise. If it rains hard enough, water begins to pool on the surface. And as the sea level rises, that also lifts the groundwater level.
For the last decade, the city has been trying to understand what will happen as that waterline continues to creep up. Can the people of South Dunedin adapt and continue to live with this unruly neighbour, or will they eventually have to abandon this place where thousands of people have created more than a century’s worth of infrastructure, homes and connections? And if they have to leave, how long have they got? These are questions that coastal communities around the country are grappling with. The answers will reshape parts of the country forever.
How do you decide when it’s time to go?
When Eleanor Doig’s labradors dig holes in the backyard of her Musselburgh cottage, it’s not long before they hit water. Eight years ago, that backyard was entirely submerged.
On June 3, 2015, it started raining and didn’t stop for 24 hours. In total, 175mm of rain fell. The streets became streams. Water, mixed with sewage, intruded into around 1200 homes and businesses, causing an estimated $138 million in damage. Aerial photos show what looks like a brick-and-tile, working-class Venice.
Doig’s property forms the low point in her block, draining the sections surrounding it, but fortunately her century-old home was elevated enough to avoid being flooded. Her work premises, at Idea Services in Wesley St off Hillside Rd, was flooded up to the curtains, however. “It was terrifying for the people who lived on that street,” Doig says.
As the water began to drain away, the community was faced with a new, potentially more ominous threat. Just over a week after the flood, the then-mayor David Cull said it was time to start considering the “end game” for South Dunedin. In an article in the Otago Daily Times, Cull said houses might eventually have to be bought by the government and bulldozed to create room for better flood defences, or possibly for managed retreat, in which parts of South Dunedin would be left to their fate.
For those still clearing sodden possessions from their homes, the words ‘managed retreat’ sounded like ‘abandonment’, Doig says. The south has long had an uneasy relationship with the central city. “It has a history of deprivation and being ignored.”
The area, south of the railway tracks that cut through the city, has long been the working-class heartland of Dunedin. Heavy industries began establishing there as early as the 1880s. University of Otago associate professor John Stenhouse says it soon became “the most densely populated, heavily industrialised and working-class urban area in the entire country”. “Rope making, brick making, match making and other industries flourished in the flat area and they attracted labour,” Stenhouse says.
That labour needed somewhere to live and as room ran out, the swampy tidal flat to the south was drained, reclaimed, and replaced with tightly packed cottages fronting tightly packed streets. The back blocks of South Dunedin still have a Dickensian air. The buildings extend almost to the footpath with out-houses out back and just enough room for a clothesline to catch the prevailing southerly breeze.
As the Otago gold rush petered out, Dunedin, and the south of the city in particular, fell into decline. Many of the industries closed over the next century, culminating in 2012, when the suburb’s largest employer, the Hillside Engineering Workshops, announced it was shutting down after a lucrative government railway-wagon contract was won by a Chinese firm.
The following year, South Dunedin scored 10 on the government’s deprivation index, a measure of socioeconomic hardship, putting it in the bottom 10 per cent of the country.
Over time, a distrust in the city council was also seeded. Plans to build a library for the community were deferred for decades. More than one person I spoke to recited an anecdote that when the library was first mooted in the 1970s, one of the councillors remarked that it wouldn’t be worth the investment, because the residents probably couldn’t read.
South Dunedin’s existence depends on its infrastructure functioning. The surrounding hill suburbs drain into this flat basin. The shallow groundwater means it can quickly become saturated, and because there’s no longer a natural outlet for the water most of it has to be pumped out into Otago Harbour.
After the 2015 floods, an investigation found the pumps and drains had failed. Three-quarters of the mud tanks in the drains in South Dunedin weren’t properly maintained, curtailing the water’s flow, while the pump system was faulty. All up, this meant the flood levels were about 20cm higher than they would have otherwise been. Many in the community ultimately held the council responsible for what happened to their homes.
When the council then said the community might be “left to their fate”, Doig says the response was “rage”.
GNS principal scientist Simon Cox. Photo: Supplied.
“I don’t want to see my city ruined.” It’s more than eight years on from the 2015 floods when I visit South Dunedin for a community meeting, a kind of brainstorming session about how the suburb can respond to the rising seas. Ten minutes in, the yelling has begun.
Council consultation meetings are often tense. When the stakes are existential, they can boil over.
Compounding the challenge is the indeterminate nature of the threat. There are no precise answers when it comes to sea level rise, but a lot of questions: how much will the sea level rise, at what rate, and what will it do to the land, roads, pipes and homes of those who live in the way?
So far the changes have been imperceptible for most. Measurements off Dunedin’s coast show the sea has risen by about 18cm since 1901, an average rate of about 1.5mm a year. But the rate of rise has almost tripled over that time and is expected to accelerate more rapidly.
The speed and extent of sea-level rise depends on how much greenhouse gas humanity emits in the coming decades, and how the world’s glaciers and ice sheets respond to the changing climate – something that’s proved difficult to pin down. But the direction of travel is clear. Even the most conservative estimates project that we’ll experience the same level of sea level rise we’ve had over the past century within the next 30 years. The Ministry for the Environment’s latest projections set a range of sea-level rise of between 20cm and 32cm by 2050; 44cm to 109cm by 2100 and 68cm to 201cm by 2150, with the level of uncertainty increasing the further the projections extend. The latest Intergovernmental Panel on Climate Change (IPCC) report said sea level rise of 15 metres by 2300 cannot be ruled out if greenhouse emissions continue to climb.
New Zealand is particularly susceptible. It has the ninth-longest coastline in the world, and it’s been estimated that every 10 centimetres of sea level rise will put an additional 7000 buildings, 133 kilometres of roads and 10 kilometres of railway line at risk.
However, exactly how sea level will affect any one location depends on many other factors: whether the ground is rising or subsiding, how deep the groundwater is, whether the ground is predominantly sand, rock or soil, whether the beaches and dunes are eroding or accreting and whether the place takes the brunt of the ocean’s waves, or is in a calm harbour.
It’s these questions that GNS principal scientist Simon Cox has spent the last six years trying to answer in South Dunedin. He says when he started the project, it was like trying to understand a problem with the lights off. There were only four boreholes monitoring groundwater in South Dunedin, which were installed between 2009 and 2014. This was expanded to 27 in 2019 and to 36 in 2021. Each monitors the groundwater every 15 minutes, detailing exactly how it responds to rainfall, tides and storm surges.
Initially it was feared that the groundwater was strongly linked to sea level, rising and falling with the tides – two of the four original bores had been tidal. This would mean that storm surges would push the groundwater up, leading to water breaching the surface and exacerbating the effect of flooding.
Fortunately, the new wells have shown that most of South Dunedin’s groundwater isn’t tidal and is partly isolated from the sea. Rather than storm-surge peaks, the impact of sea level rise will be slow but pervasive.
It means there are more options to prevent flooding and other issues that arise, he says. “Because it’s less permeable, you can look at options to manage water, such as better drains and pumps. But if it was strongly linked to the ocean, then there’d be too much water flowing in from the sea to manage. You’d basically have to pump out the Pacific Ocean.”
Nonetheless, over time, the groundwater will rise. First will come the floods.
“What happens is that when the water gets closer to the surface, the ability for the ground to absorb any rain like a sponge gets less and less, to the point where it can’t absorb any more,” Cox explains. “So it suddenly changes from a sponge surface, to being impervious, which means everything has to go through the stormwater system immediately, as opposed to over a week or so.
“So if it rains hard, it’s going to flood. We’ve been really lucky since 2015 that most of the events haven’t caused damage, but it’s getting scarily close. It’s these massive peaks coming through all at once that the system can’t cope with, so you end up with these episodic events first of all, well before the groundwater comes to the surface.”
Rising groundwater will also have a pernicious effect on infrastructure, undermining the foundations of buildings and roads, possibly intruding into sewers and causing systems to fail. “It’s not just one thing, it contributes to all of these different fundamental things.”
These issues will become more prevalent once sea-level rise exceeds 30cm – a level expected by mid-century. When sea-level rise hits 40 to 50cm – a level expected in about 60 years – groundwater will start emerging as widespread springs
There’s some good news. The land isn’t sinking and South Dunedin is fortunate to be protected by sand dunes to the south – although they’re eroding and being monitored. It is more vulnerable to flooding via the harbour to the northeast – the waterfront on Portsmouth Drive was a tidal flat as recently as the late 1970s before being reclaimed. NIWA modelling shows that 60 to 70cm of sea-level rise would mean most of South Dunedin would be inundated via the harbour during a one-in-10-year storm surge, although the reclaimed land could be elevated further to prevent this. As sea levels rise, building more infrastructure to keep water out will likely become more and more costly and harder to justify.
“It seems to me that you could develop engineering solutions to reduce the issues with periodic flooding from sea-level rise, and we should to a certain extent, but then you’ve only got a certain amount of time before the next problem comes along with water coming out of the ground or causing damage to the roads. And in that window of time you’ve got to balance the city’s investment into the stormwater system with how long it’s going to function for. That’s where it gets tricky.”
The council has earmarked $37 million to reduce flood risk in South Dunedin over the next decade, with plans to improve the drainage system and install better pump stations to get water out. A report commissioned by the council 2014 estimated it would cost about $10.3 million to develop a pumped-drainage system that could alleviate flooding associated with 30cm of sea level rise, while it would cost $65.1 million to build seawalls and pumps to cope with 80cm of sea level rise. But the sea will likely keep rising, and so will the costs. At what point do the costs exceed the benefits?
…it’s been estimated that every 10 centimetres of sea level rise will put an additional 7000 buildings, 133 kilometres of roads and 10 kilometres of railway line at risk.
“It’s a really gnarly problem,” Jonathan Rowe says. Two years ago, Rowe got the job to manage the South Dunedin Future programme, a collaboration between Dunedin City Council and Otago Regional Council to plan what happens next.
Simon Cox’s work will soon be used to investigate potential engineering solutions to combat the rising seas. Ideas have included inverting the roads, so they basically become canals, draining water out of the suburb when it floods, rather than displacing water into people’s homes. In the meantime, Rowe is working with the community – and the councils – to understand what a future with more water might look like, and what people want to protect.
The first step has been to rebuild the relationship with the community. University of Otago research professor Janet Stephenson, whose work focuses on how communities can best respond to the challenges of climate change, was involved in the council’s efforts to re-engage the community in the wake of the flood.
Consulting on the topic of managed retreat is inherently fraught, she says. It’s a discussion which threatens people’s homes, livelihoods, and communities which have formed over generations. But she says what’s made these projects successful overseas is if they’re supported and developed by the community, not imposed by the council. “You need to approach the community from a position of humility, not saying we have all of the answers, but saying ‘we don’t know what to do yet, and we’d really like you to help us’.”
And that’s what the council did, Stephenson says, beginning with a series of public meetings in 2016. “That was the most extraordinary moment, to me, of a step change in that relationship.”
A group called the South Dunedin Community Network was later formed with the aim of bringing together all of the different groups and services in the area. Elanor Doig became its inaugural chair.
The council has since held hundreds of meetings with the community. At the public meeting I attended, however, the challenge of developing a community-led solution became clear. Some don’t believe that the seas will rise as scientists predict. One person at the meeting believed that storms were being engineered by global governance groups to control the world’s population.
Ray Macleod leads a group called the Greater South Dunedin Action Group, which was formed in the wake of the 2015 floods. He works as a project manager, with a background in civil engineering, and is sceptical about sea-level rise, and anthropogenic climate change in general.
Jonathan Rowe manages the South Dunedin Future programme. Photo: Supplied.
It’s clear not everyone will think the process is fair or necessary; not everyone will be able to stay.
“The flood wasn’t a climate-change event, it was a local-authority incompetence event,” he says. “If we put in good engineering systems, with better pipes, bigger pumps and better emergency procedures we could manage the immediate risk for the next 50 to 100 years while we figure out what will happen with climate change. We’ve got billions of dollars invested in existing infrastructure in South Dunedin. We can’t engage in managed retreat on the basis of the 2015 flood.”
But while the community meeting threatened to be derailed by a vocal minority, the rest of the attendees soon piped up and defended the process and the meeting continued – something Eleanor Doig says was a success in itself.
People were later encouraged to write down ideas on how the city could adapt on post-it notes and stick them to a map of South Dunedin. Among notes calling for more wetlands and “bigger pipes” was a note that said “climate change hoax”. Another said “I want to stay”.
Jonathan Rowe says that last note has been repeated at meetings time and time again. “Their biggest fear is being red-zoned or red-stickered. But, people also want to know what the plan is – what are the rules, how will it work, what’s the system. And thirdly, if they do have to move, whatever system we come up with needs to be fair.”
Not everyone will get what they want, however. It’s clear not everyone will think the process is fair or necessary; not everyone will be able to stay.
But Rowe sees opportunity in the coming disruption. The suburb is already characterised by a lot of old, run-down housing and ageing infrastructure. Perhaps, he says, adaptation could be a way to address these long-standing issues, while making more space for water.
“We’re saying that if things start to escalate the way they could in various climate scenarios, should we just continue to do what we’re doing and try to engineer our way out of this, or are there better ways of managing this? And could that not only make this place safer, but better? Could a future South Dunedin have more parks, more greenspace, more open watercourses, more wetlands? Could it have better high density housing around key transport routes? And can we turn climate change into a broader urban regeneration and development project? We’ve found asking these questions and flipping the framing around to show the opportunities, people really respond to that. It’s a way out of it, which I don’t think we’ve had before. Previously it’s just been that there’s problems, and the problems are going to get worse.”
It’s worth remembering that while groundwater will likely rise to the surface through significant parts of South Dunedin by the end of the century, much of the area was partially underwater just a little over a century ago. Rowe says it may be feasible to further raise selected parts for development over many decades – not fight or flight, but a bit of both.
“South D is a fabulous spot,” Rowe says. “It’s flat, it’s sunny and close to awesome amenities, services and infrastructure, and it’s great for accessibility, too. A lot of people have deep connections to the place for multiple generations, so you can’t just up and leave. I think that would be a failure. This is what the programme’s all about. How do you enable a change in a way that’s gradual, planned, reflects what people want and value most, and is calibrated in a way that stays ahead of this changing environment but doesn’t get ahead of people’s appetite for change. But if we do nothing, the water will change it for us.”
It’s hard to come up with a plan. It’s harder to put it into practice.
Multiple reports over more than a decade have found that councils are ill-equipped to fund and enforce managed retreat using existing laws and if a nationwide plan and funding scheme isn’t put in place soon, an ad hoc response will cost vastly more and bring worse outcomes.
There have been repeated calls for a nationwide funding scheme, like the Earthquake Commission (aka, Toka Tū Ake EQC), to compensate property owners and give councils and central government the power to acquire land when managed retreat is required. To date, none of this is in place.
There has been some progress, but it’s been slow. When the Resource Management Act was reviewed by an expert panel in 2020, it called for a new climate-change adaptation act to legislate for these types of powers and plans. The Labour government agreed and aimed to introduce this legislation by the end of this year, but when Parliament rose in August ahead of the election, a bill hadn’t even been drafted.
However, in the final months of the government, Climate Change Minister James Shaw directed the Environment Select Committee to begin an inquiry into climate adaptation in an attempt to develop legislation with cross-party support.
When the inquiry was launched in August, it coincided with the release of two reports detailing the options and challenges involved in developing a managed-retreat scheme. One, by the Ministry for the Environment, said waiting until after a disaster to relocate communities at risk of climate change would be “reactive and costly”.
“If we fail to adapt, we may find ourselves in a constant state of recovery, with increasing risk to lives and livelihoods, property and infrastructure, taonga, culture and heritage and health and wellbeing… If a community stays in place and a disaster occurs, all of Aotearoa may share in the cost of recovering from that disaster. This will become increasingly unaffordable as the number of extreme weather events – including flooding and slips – increases.”
It also found Maori land and communities would be disproportionately affected as they were more likely to live near the coast and faced higher levels of hardship.
The report said waiting to retreat from hazard zones until after a disaster could also create costly precedents and create a moral hazard, where homeowners ignore the risks associated with climate change because they believe they will be well-compensated if they have to move.
“Urgency increases the risk of investing in the wrong actions or places. First, money is primarily spent where disasters are most visible rather than on places that have the greatest overall need. Second, expectations as to the future funding approach are set through ad hoc investment, rather than an enduring approach.”
The MFE report stopped short of making recommendations. However, a report by an expert working group, released in tandem, was more forthcoming. It said any compensation scheme should aim to avoid hardship by providing adequate housing to those affected. But, controversially, it believed that preserving people’s wealth or protecting property owners from the inherent risks of ownership were not “legitimate objectives of the funding system”.
Instead, it proposed that homeowners would be paid either the rateable value of their house, or the cost per square metre of building a new home the same size, with payments capped under each scheme. Holiday-home owners, however, wouldn’t receive compensation at all, “but could receive assistance for removal, demolition and clean-up costs”.
Landlords would receive “less generous” compensation and would only get paid out if they bought a new long-term rental in another location. Compensation for businesses would be “based on hardship, which would be assessed by means testing”, but this could be as low as 50 per cent of the rateable value and contingent on the money being used to relocate to a new building.
Submissions to the committee closed on November 1, but its future is in limbo. It dissolved when parliament rose ahead of the election and it’s unclear whether the next government will continue with it, although, both National and Act have voiced support for the inquiry.
While this work plods on, It’s houses continue to be built in areas that will be at risk from sea-level rise.
Councils are meant to follow the New Zealand Coastal Policy Statement, from 2010, which requires them to “adopt a precautionary approach to use and management of coastal resources potentially vulnerable to effects from climate change”. It also requires councils to identify areas that are at risk from sea-level rise over the next century and to “avoid increasing the risk” in these areas.
However, in practice, development is still occurring in low-lying coastal areas and some councils have been hesitant to quantify the risks posed by sea-level rise. In a number of cases, councils have been taken to court – and lost – for restricting development on areas identified as at risk of inundation. One planner, speaking off the record, said some councils were avoiding commissioning reports on sea-level rise because the information would end up on Land Information Memorandum reports (LIM reports) and open the council to litigation.
Rob Bell, who has spent decades advising councils on climate-change risk while working for NIWA and through his own consultancy, helped write the Coastal Policy Statement. He says while some councils are restricting development on low-lying coastal land, progress has been slow due to the 10-year time frame of district plans. He says there needs to be more direction from central government to stop further developments. The Labour government was developing a national policy framework which would remove some of the “wriggle room” available to councils, but the change in government means the future of this work is also uncertain.
“It’s been a fraught area and a bit frustrating,” Bell says. “We had a head of steam up and I really think we need that national direction sorted out quickly if we can. Otherwise some of these developments are going to sneak through. So we need to really put the brakes on hard in the coastal environment.
“That doesn’t mean a complete freeze on doing anything. But every decision needs to consider whether we are locking ourselves into a future building and maintaining more and more seawalls that could potentially breach at any time.”
Victoria University of Wellington policy-studies professor Jonathan Boston, a member of the expert working group on managed retreat, says the existing regulations are inadequate and change has been sluggish.
“The existing regulatory framework is not deemed to be fit for purpose, particularly in a context of a dynamic and changing environment with growing risks and where there is such pressure from developers and infrastructure providers to press ahead,” Boston says. “And it’s an asymmetrical situation, with very powerful interests wanting development and much weaker interests seeking to prevent that development. So we need to have a stronger regulatory framework to prevent councils from making foolish decisions.”
In South Dunedin, you can still see builders busy at work, putting up new houses. Buildings have to have a minimum floor level – generally 40 to 50cm above ground level, depending on the site. On sites at risk of flooding they also have to be relocatable – although a Dunedin planner speaking off the record said this requirement was often loosely interpreted: “A dwelling on a concrete slab is technically relocatable so there is a pathway really for any building to not be constrained too greatly in the coastal or flood zones.”
One of the largest and lowest-lying greenfield sites in South Dunedin could also potentially become a new housing development. In 2021, it was announced that the 100-year-old Forbury Park race track was closing and part of the 12-hectare site was later sold to a housing developer. This sale was later challenged in court, after Harness Racing New Zealand opposed it. The block is now back on the market. The land sits just beyond the dunes at St Clair and was mostly underwater during the 2015 floods.
Jonathan Boston believes it may require more disastrous floods before robust rules are developed. “My only hope is that a learning culture will occur over decades and people will become accustomed to the fact that these risks are real, not imaginary, and people will witness situations where a community has refused to move and has then been inundated and suffered the consequences of that. People will then gradually come to a greater appreciation of the risk and a greater willingness to accept that they need to take precautionary measures.”
While the regulatory wrangling continues, Jonathan Rowe is trying to ensure that South Dunedin won’t be that disastrous example.
He’s helped develop a voluntary scheme where houses at risk of being flooded in South Dunedin could be bought by the council over a number of decades. The idea took root after it was discovered that about half of the houses in the suburb had sold within the last decade, meaning a voluntary buyout programme could acquire a significant number of properties within a relatively short period of time.
“It means there’s no red-stickering or red-zoning, but you could start to acquire land strategically in areas that we might later need to build new infrastructure, to intensify, to retreat from, and you could have this bubble away in the background. It avoids this big shock. It’s gradual, it gives people a plan, it gives them a sense of direction and it doesn’t force anyone to do anything.”
If the council had purchased every property that sold over the last decade, it could have bought roughly half of South Dunedin for $749 million – a little over double the cost of restoring Wellington Town Hall. Property prices have risen since then, but Rowe believes it could still be affordable.
“Realistically, we’re not going to buy every house that goes on the market and there could be potential negative impacts from an intervention in the market of that nature. But we’ve said, hypothetically, if you had to change South Dunedin’s land use over 100 years, that works out to be 65 properties a year at an average of $407,000, which is about $26 million a year. So we’ve worked out a budget of $132 million for a five year trial.”
The council has put together a business case and sent it to Treasury and the Finance Minister for feedback in July, but it is yet to hear back. Rowe is hoping the council can secure government funding for a trial.
“We think it’s a really good concept, but we need to test the detail. I think the key point is we don’t need to know what all of the solutions are before we start buying property… But gradually, over decades, it enables the reshaping of the urban form in South Dunedin, where we get more investment in areas that are lower risk, less investment in areas that are higher risk, and new infrastructure, more greenspace, more blue space – and in floods the water goes where we want it to: into parks, pipes and wetlands and not into peoples homes and businesses.”
Houses wouldn’t immediately be bulldozed, but could be owned and rented out by the council, potentially for decades, which could help to pay for the buyout programme.
Eleanor Doig has recently stepped down as chair of the South Dunedin Community Network, but she says there’s been a renewed sense of hope in South D. The Hillside workshops are reopening, following investment from the government. The council has decided to build a new $21.4 million library. Kmart is coming to town, relocating from George St. And soon, there might be a plan for the suburb’s future.
“It’s sad but true, that it takes a catastrophe to energise things,” Doig says. “Now the narrative is changing and there’s a sense of opportunity and possibility. There will be disruption, people will lose their houses. Our focus is that any change has to be as fair and just as possible. It will be decades in the making, but I don’t see this as the death of South Dunedin at all.”
George Driver is North & South’s South Island Correspondent, a role supported by NZ on Air’s Public Interest Journalism Fund.