‘We haven’t learnt much’: Environmental advocate lays down challenge to councils over flood mitigation

10:19 am on 8 April 2023
These aerial shots taken before and after Cyclone Gabrielle show a section of Gisborne's Waipaoa River between Ormond and Te Karaka. The Waipaoa River burst its banks in several places, forcing people to evacuate and make for higher ground

These aerial shots taken before and after Cyclone Gabrielle show a section of Gisborne's Waipaoa River between Ormond and Te Karaka. The Waipaoa River burst its banks in several places, forcing people to evacuate and make for higher ground Photo: LINZ

Nature-based solutions - the words flash up in bold on a Gisborne District Council screen.

It is late March, and Forest & Bird freshwater advocate Tom Kay is presenting to 13 councillors, the mayor, a selection of council managers, and a handful of onlookers about the importance of rethinking natural disaster mitigation.

Kay wasted no time, and pulled no punches.

The message was sobering - more frequent and intense rainfall should be expected across the country due to climate change, more communities will be caught in harm's way and more lives will be lost.

Then he delivered the knockout blow.

"It's not just climate change that is causing this problem. We have engineered or contributed to these disasters.

"We have taken the wetlands, or sponges, out of our landscape."

Over the course of his 10 minute slot, Kay listed a series of devastating floods Aotearoa has experienced in the past five years - the sort that people refer to as once-in-a-generation events.

Edgecumbe in 2017 was followed by Canterbury which was followed by the West Coast which was followed by Nelson which was followed by Auckland, and on it goes.

Kay's message was timely - it had been just under 50 days since Cyclone Gabrielle made landfall, wreaking havoc on the East Coast, and beyond.

The impact of this cyclone (the fifth in just two years), has drawn endless comparisons with 1988's Bola, which was widely regarded as the worst in New Zealand's recorded history.

While rainfall levels did not reach that of Bola's 900 millimetres in 72 hours, this time around there was another factor at play - forestry slash.

Debris and whole logs from the East Coast's burgeoning industry filled waterways, taking on the role of bulldozers in the roaring waters of local rivers.

Kay's presentation rolled on, and a paper that just celebrated its 35th birthday flashes up on the screen: Inquiry Into Flood Mitigation Measures Following Cyclone Bola, dated December 1988.

The report portended danger, speaking of how the draining of wetlands - which act as buffer zones, or sponges - intensified flooding in that historic storm.

"A possible effect of climate change is that cyclones of some form could pass close to New Zealand with increasing frequency. It may be that in retrospect, the Bola storm will not be regarded as such an extreme event."

Forest & Bird freshwater advocate Tom Kay presented to Gisborne District Council last week on nature-based solutions to extreme weather events. He is calling on all councils to rethink how they approach the natural environment.

Forest & Bird freshwater advocate Tom Kay presented to Gisborne District Council last week on nature-based solutions to extreme weather events. He is calling on all councils to rethink how they approach the natural environment. Photo: Supplied

Were those concerns, penned in 1988, paid heed?

"We haven't learnt much," Kay told Local Democracy Reporting.

"We might have learnt one thing, which is to plant trees, but we planted pines which wasn't a good idea in retrospect."

Kay has a way of making the seemingly mundane come to life as he described the important role wetlands played in maintaining a healthy and balanced ecosystem.

Home to many of New Zealand's endangered species, he said the wetlands were the fabric that bound much of New Zealand's natural environment together.

They were like vital organs that filter water, he said.

Meanwhile, the country's preoccupation with draining them has likely played a significant factor in the ongoing struggle against flood mitigation.

About 90 percent of the country's wetlands have been drained - often for development - and the results have been devastating, he said.

This peat wetland on the Kāpiti Coast has been restored from pasture to its former state. Around 90 percent of New Zealand’s wetlands have been drained.

This peat wetland on the Kāpiti Coast has been restored from pasture to its former state. Around 90 percent of New Zealand’s wetlands have been drained. Photo: Russell Bell/Supplied

"Wetlands are like sponges in the landscape. They basically absorb water when we have heavy rain and then they slowly let that water out when we have drought conditions.

"We've tended to drain them in the past because we have this colonial perspective that wetlands are wastelands. We treat them as swamps."

Kay said that when Pākehā came to the country, many of them turned wetlands into pasture for livestock farming.

It was not until 2020 that the government tightened up those rules, but even now, protection was not guaranteed, he said.

"It's like the Cyclone Bola report says, we've taken away our wetlands, and we've therefore taken away the buffer zones for extreme weather events.

"You've got these huge natural water storage systems that we should be restoring, that we have naturally in the landscape … but instead we think 'we need to build a dam in this valley (for drinking water)'."

With so much of the country's wetlands now converted into farmland and urban areas, Kay said Aotearoa has lost its intergenerational knowledge of places that "used to flood a lot".

Whole suburbs have been built on reclaimed land, so flooding issues tend to go a lot deeper than the usual explanations of councils failing to clear drains, he said.

No management system was safe when Kay was in the vicinity - he now took aim at the historical approach of flood management in New Zealand, which was to straighten rivers and line them with stopbanks.

That technique, which aimed at trying to get water out to the coast as fast as possible, has proven disastrous for wildlife and humans alike.

Swimming holes and pools, which act as natural habitats for many fish species, have been destroyed.

Meanwhile, stopbanks - which aim to direct the flow and protect communities - ultimately elevate water levels above the floodplain.

When those stopbanks ultimately fail, the water is released with such a massive energy that the mitigation efforts often prove to be more of a risk than a safety net.

"We tend to think of those stopbanks as protecting everyone, but they have exceedance thresholds, and floods that are bigger than those stopbanks will over-top them.

"They have the potential to blow out because the loading behind the stopbanks is enormous.

"We've tried to manage what is essentially unmanageable," he said.

All of this, coupled with deforestation causing more water to flow off hillsides, has created the perfect storm.

Rivers needed more space than what people were often willing to give them, Kay said, and the results have been disastrous for communities built too close to them.

Gisborne's Waimatā River ballooned in size during Cyclone Gabrielle, putting homes and businesses on the line. Forest & Bird are challenging some of the typical practices used by councils to mitigate flood risk.

Gisborne's Waimatā River ballooned in size during Cyclone Gabrielle, putting homes and businesses on the line. Forest & Bird are challenging some of the typical practices used by councils to mitigate flood risk. Photo: Ben Cowper/Gisborne Herald

When it comes to finding solutions, he has a hard word for councils: stop treating the environment as a "nice-to-have".

While infrastructure, roading and communications are important, those projects could not come at the expense of looking after the natural world, something which we all rely on.

Stronger rules protecting wetlands needed to not only be introduced, but also enforced, and restoration remained critical.

Kay also believed councils needed to have more honest conversations with their communities about flood levels, and not shy away from explaining the risks of living in certain areas.

"The environment is critical, and we need to put that first, otherwise we've got nothing."

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