More trees, less pavement, and the surfacing of natural streams could help floodproof Auckland as extreme weather events are becoming more frequent.
Last Friday's 1-in-200-year floods have kicked off a debate about how the country's largest city can better prepare itself for a more volatile climate.
University of Auckland senior lecturer Timothy Welch told Breakfast that there was no shortage of options for making the isthmus city more flood resilient.
"Any city would struggle to cope with that much water in a single day, but our infrastructure is really old... we upgrade here and there, but the entire system really needs to be rethought to avoid this kind of thing in the future," he said.
The researcher said ideas included replacing impermeable asphalt with more porous materials and planting more trees and berms that can slow down and filter rainwater.
"If we look at the old historical maps of the city, we can see there are all sorts of streams that we've buried and put into pipes – one simple thing we could do is to start bringing some of those out of the pipes… and let them be natural reserves again.
"That's kind of just the beginning of the list. [There's] all sorts of different infrastructure that's attractive to people, but also mitigates a lot of that storm."
Welch pointed to existing examples in Auckland - like the relatively new Stonefields subdivision, which included a "floodable park" that could hold more water than traditional pipes could manage.
Meanwhile, he said there were also examples of cities overseas - like Singapore - that mitigated extreme rainfall with parks and other intentional green space.
"We could have a really attractive urban environment and try to push more density up - instead of sprawling out into our existing wetlands," he said.
Rākau to help tackle climate disasters - arborist
Speaking to Breakfast, arborist and tree protection activist Zane Wedding said there could be "significant improvements" in mitigating the disastrous impacts of climate change by having more trees.
"If you couple policies [to reduce emissions] along with the protection of our green spaces - our mature rākau, our awa (streams), then there are significant improvements we can have to kind of minimise what's happened across Tamaki Makaurau," he said.
"These mature rākau will hold up close to 400 litres of water before they release it into the ground. In fact, mature rākau pulls 16 tonnes of water out of the ground every year.
"Unless we're able to protect these trees, then they do not have that staggering effect holding this water up in the air and not just pushing it straight into our stormwater drains which we have seen," he said.
Wedding said the prevalence of impermeable surfaces created a "swimming pool" where rainwater wasn't able to keep away from homes and buildings.
"We have just sealed our city in concrete and tar seal. And we've created this complex concrete construct that just acts as a swimming pool."
He added that new homes in the city needed to be built with more green space, with trees to create a "sponging effect" when extreme volumes of rainwater hit.
Communities may have to move due to extreme weather
Yesterday, Emergency Management Minister Kieran McAnulty told 1News that some coastal communities around the country would need to begin a managed retreat.
Emergency Management Minister Kieran McAnulty visited what's left of State Highway 25A. (Source: 1News)
Due to climate change, extreme weather events will become more intense and more frequent – leaving critical infrastructure vulnerable.
"That's something the Government has signalled - getting our planning right so that we don't build in areas that we know are going to flood or become prone to erosion.
"But also looking at, is it justified to continue in an area when we know it's going to be prone to climate change?" he said.
Auckland has recorded eight-and-a-half times its normal January rainfall. (Source: 1News)
He said how quickly this managed retreat would happen was dependent on what individual communities wanted for themselves.
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