A mayor’s decision whether to flood his own city

The storms hit Wellington this Monday morning. As Hutt City’s mayor came over the top of the Wainuiomata Hill Road at 7am on his way to work, he found traffic stopped by a car that had hit a slip and spun out. Roads were closed and homes lost power as about 50mm of rain pounded the region.
Campbell Barry looked out over the valley at the flooded Hutt River and Waiwhetu Stream. “And I thought to myself, is today going to be the day? We are the most densely populated floodplain in New Zealand. If the Hutt River was to break its banks, it would be billions of dollars damage to property and obviously put human life at risk.”
For Barry, there was a worrying question: If a cyclone approaching the magnitude of Gabrielle hit the region, he would have to make an unenviable decision. “We might have to do a controlled demolition of the stop-bank to flood part of the city, to avoid flooding the entire city.
(“And I thought to myself, how do I delegate that decision to the chief executive in the future!”)
It’s to avoid such grim impacts that Hutt City and Greater Wellington Regional Council have together embarked on a project that may sound counter-intuitive to some. They have bought up 125 properties along the side of Hutt River, so they can demolish them and “retreat” the stop-banks further from the river, and towards the central city.
Theirs are among voices pleading for the Government to urgently consult on a plan divvying up the cost of paying for communities’ strategic retreat from unsafe coastlines, vulnerable flood-plains and unstable hillsides.
Parliament’s finance and expenditure select committee is considering submissions in its inquiry into climate adaptation. In a submission published this week, the Climate Change Commission recommends new targeted funding and financing instruments, both public and private, to support adaptation.
The submission from chair Dr Rod Carr says an adaptation framework should set out how private investments can effectively account for risks arising from climate change while also supporting inclusive and equitable processes and outcomes.
The Government should prepare a strategy and plan to develop the climate adaptation workforce, the submission says, and make the direction, scale and pace of change required clear.
And Insurance Council chief executive Kris Faafoi says the industry wants to get assertively involved in decisions about building houses and subdivisions, before councils sign consents and developers break ground.
Existing regulation isn’t just unhelpful – it’s actually obstructing communities and businesses from any strategic managed retreat.
There’s agreement from many councils and from experts like consultants WSP: Local authorities conducting voluntary risk assessments produce critical data, but a systematic, national approach is needed to inform adaptation and managed retreat planning effectively.
Regional councils also face constraints related to maintaining existing flood protection measures,even when they may not be the most effective long-term solution. And councils can’t just withdraw services from areas designated for managed relocation if some residentscontinue to reside there.
There is perhaps a greater degree of political consensus around the need to adapt to climate change than there is to reduce our emissions in order to mitigate it. On reducing emissions, one National Cabinet minister distinguishes between the Greens who see climate change as “an existential threat to the planet” and National, which he believes has “a more balanced view of the world”.
But on adaptation, there’s no science or even complicated economics needed to understand the challenge. It’s basic arithmetic. We can pay a lot now to strategically move or protect home and infrastructure – or we can pay even more, later, in both financial and human cost.
Mākara Beach was hit by Cyclone Gita in 2018. Homes were flooded and property was destroyed. The following year, a plan was announced to raise the beach crest, constructing a sea wall, clearing gravel from the stream’s mouth, and reinforcing its bank.
But it’s quickly become apparent that won’t be enough.
Wellington’s (Green) mayor Tory Whanau says she’s met with people in the community of Mākara Beach to discuss options in the face of 50 years of rising sea levels and coastal erosion. The same discussions are needed in parts of Miramar.
Soaring insurance premiums mean Wellington City Council has made the difficult call to cancel its insurance on about $3 billion of assets, she says. Instead, it’s selling its share in Wellington International Airport to create what will be, quite literally, an extremely rainy day fund.
There are about “Trying to ask a community to move based on some unknown factors is really a big ask,” Whanau tells Newsroom. “It’s really, really hard, it’s really expensive, and we don’t have any answers yet.
“We’re not talking to insurers yet. We’re just talking directly to the community. There’s no real government support or investment in this programme yet, and it’s going to be really, really expensive.”
Mayors and councils around the country are grappling with similar challenges. And of course, central Government.
Climate Minister Simon Watts told the big Building Nations infrastructure conference this week of the need to start work quickly on long-lasting changes to how and where we live and work. “We all genuinely acknowledge that this does need to be enduring, because if climate change adaptation is a generational challenge, it’s going to outlast my role in political cycles.”
Back in the Hutt Valley, many still remember the big flood of 1976, in which homes slipped down hillsides, and a US Coastguard helicopter rescued workers from roofs. Climate scientists said that was a 1-in-100 year deluge, perhaps even 1-in-500 in some parts of the region.
The rainfall that day topped 150mm. The rainfall this week on Monday wasn’t so severe – but was still close to 50mm over six hours. These events are happening more and more often. Wellington’s rain gauges have more often topped 100mm in a day – among them the downpours of Feb 2009, May 2016, Nov 2016 and April 2017.
In the Hutt Valley, councils consulted with their communities about upgrading the existing flood protection scheme at the turn of the century. It took until last year for work to finally begin, and won’t be completed until 2030.
Meanwhile, floods will keep coming. Storms will keep coming. Heatwaves will keep hitting. Sea levels will keep rising. IAG corporate relations manager Bryce Davies has said coastal communities such as the Hutt Valley’s Petone won’t exist in 30 to 50 years. “Petone can’t be there. It won’t be there,” says. “We cannot protect that now. We cannot protect South Dunedin. There are parts of Napier that we cannot protect, no matter what we do.”
Professor Tim Naish, from Victoria University of Wellington, said last month: “That road to Eastbourne and the Petone foreshore will be experiencing the historic flood, the flood we get every hundred years, the big coastal flood – it will be an annual event. It will happen every year.”
Greater Wellington Regional Council’s has pointed to its Hutt Riverlink project as an example of a structural solution to flood resilience and climate adaptation, to improve the flood defences adjoining the Hutt city centre.
In its select committee submission, it says these solutions often need the purchase of properties to achieve adequate flood mitigation without creating future problems for ongoing flood risk and maintenance.
But for the Hutt Valley, at least, it’s also a chance to protect and enhance the natural environment affected by the infrastructure works, through the introduction of threatened forest types, which will ultimately leave natural environment better off.