Drone footage of flooding on Swamp Rd and surrounding area in Puketapu, Hawke’s Bay on the Tuesday morning following Cyclone Gabrielle. Video / Matt Wheatley
“It no longer makes sense to talk about events happening every 100 years,” Finance Minister Grant Robertson told the Auckland Chamber of Affairs last week. “We will deal with them on a regular basis.”
True that. One of the many brutal lessons from Cyclone Gabrielle and the Auckland anniversary weekend storm is that if extreme weather can happen this year, it can happen again next year.
Another lesson: If the storm was unprecedented this time, it can happen again.
Rainfall in Auckland between 27 and 28 January was 60% more than expected in a “1 in 100 year” storm. No one thought it could be that bad, yet it was. It was the same with the people of Hawkes Bay and Tairāwhiti. And we will definitely experience this terrible record again.
Some forecasters prefer the term “1 percent chance,” which means the same as “1 in 100,” but it carries the message that, however small, there is a real chance it could happen.
But that’s not enough, partly because it’s obviously outdated and partly because it still carries the message that we don’t need to worry too much.
The entire climate change debate has been undermined by numbers like this. We look ahead to what the world might be like in 2050 and if, or when, the temperature will warm up by 2 degrees compared to pre-industrial times, or 3 degrees or more.
The message is that a climate crisis awaits us in the future. That we have 30 years before having to change course.
Maybe we should forget about those numbers too. The climate crisis has engulfed us now.
Green co-leader and climate change minister James Shaw said last week: ‘I don’t think I’ve ever felt so sad or angry about the lost decades we spent arguing and debating whether or not climate change was real, whether it was caused by humans or not, whether it was bad or not, whether we should do something about it or not, because it’s clearly here now, and if we don’t act, it will get worse.
He’s right, but despite the newfound consensus that something needs to be done now, the ferocity of these storms has revealed that we don’t know enough about where and how we can live safely.
Sadly, misleading numbers aren’t the only shaky ideas standing in the way. Here are three more.
Flaky idea 1: “Don’t build on a floodplain!”
Wait. Almost all cities in the world are built on a river or a coast, or both, and therefore are located on or near floodplains. The history of cities is a history of how to manage the risks posed by water.
There are many ways to do this. In the Netherlands, most people live below sea level, protected by dikes. In many Asian cities there are houses on stilts above the water. In Auckland itself, the suburb of Sandringham was a swamp, what we now call a wetland, before it was drained and turned into a suburb.
Stormwater management in Auckland is the responsibility of Healthy Waters, a division of the council. Its boss Craig McIlroy told me yesterday the city has 100,000 homes “on a floodplain.” Most of them have been there for a long time and some of them get flooded quite frequently. But in more recent developments, the news tends to be much better.
At Mt Roskill, where Kainga Ora and others are building 10,000 new homes, drains have been improved and, more importantly, “overland runways” and watersheds have been established.
On the night of January 27-28, water rushed along the streets and the suburb’s Freeland Reserve flooded, and over the next three days, the water seeped into the ground. The houses remained dry. The same thing has happened with new developments at Drury, Northcote and elsewhere.
There are some flood-prone areas that we probably shouldn’t build on, and also some sections of coast that we should retreat from. But choosing the best solutions for each area is complex and, nowadays, we don’t always rely on expensive underground pipes.
In a new major rain breakdown, says Nicholas Vigar, head of planning at Healthy Waters, they plan for perhaps 40-50% of the water to end up in drains, while 50-60% will go down an overland stream. path. Down the street at the local park.
It’s cheaper to build, easier to maintain, and perhaps most valuable, it doesn’t have the same capacity constraint.
Wobbly Idea 2: “Density Means More Disasters!”
Filling suburbs with houses puts too much strain on all water infrastructure, it is said, so drains are overwhelmed more quickly. And it creates harder surfaces for water to run off, which also overwhelms drains.
Of course it’s true: if the density is done wrong, these things happen.
But there’s nothing about density that means it has to be done that way. New Lynn is a flood prone suburb and is fast becoming a much denser part of the city. It’s not immune to flooding, but bigger and better stormwater channels and pipes are being built, along with more flow paths, and there’s a lot more to come.
McIlroy says New Lynn’s new culverts did their job well over the anniversary weekend.
Not all news is so reassuring. New building regulations that will change the Auckland Unitary Plan could mean we don’t have enough green space in urban areas. And while the city has planted millions of new trees in recent years, it has also seen the widespread destruction of many mature trees, on public and private lands.
These things clearly need a rethink.
The reality is that for cities in a world of climate crisis, density and greenery need each other, and not just to mitigate flooding.
The simplest way to build flood resistance in Auckland would be to build many more apartment buildings, say 6-10 stories, especially in places that don’t flood easily. At the same time, we would keep our parks, and we would build others, and we would convert as much public land as possible to green: the trees, the lawns, the vegetable gardens and flowers, the playgrounds, the works.
With what public land could we do this? About half the area of all wide streets that were once tram routes.
The best place to create an example of all this is Great North Rd, from Ponsonby Rd to Pt Chevalier. Or Avondale. Or beyond.
Many suburban backroads are also wider than needed for driving and parking: they could triple their shoulders, and residents could be encouraged to plant them.
I know, it’s almost absurd. Especially since there is an added benefit: public transport, walking and cycling would become more attractive and driving everywhere would seem less.
In terms of climate action, this is called adaptation and mitigation: the city would become more resilient to flooding and we would reduce our emissions. And both would be achieved through the same development strategy.
What it requires is an understanding that we should stop treating housing and transportation as separate fields of planning. They are two parts of the same thing: land use.
Flaky Idea 3: “Forget Emissions”
Despite the value of integrated spatial planning, some say it is time to forget emissions and focus only on the adaptation side. This is the new take on climate denial, and we’ve heard about it from Christopher Luxon and Wayne Brown, among others.
We have to do both. New Zealand’s emissions, per capita, are among the highest in the world. We have no right to pretend that we are exempt from liability.
Furthermore, what if we let the cause of the crisis continue unchecked, consoling ourselves that we can “adjust” our way to safety? We would build levees and bubbles above cities, then sit and wait for our well-planned “flood paths” to turn into raging, uncontrollable rivers.