Cyclone Gabrielle: How the rest of the world handles managed retreat

Hamish Cardwell for RNZ

Overseas experts in managed retreat say the owners of the worst damaged properties in recent extreme storms in New Zealand must get a seat at the decision-making table about possible red zones.

The government, the Cyclone Taskforce, insurers and local council officials are hashing out whether communities need to abandon some places after the catastrophic cyclone and Auckland Anniversary flooding.

Land swaps must be on the table

In 2011, 14 people died in the Australian town of Grantham when an "inland tsunami" flooded the settlement during extreme rain.

About a year later the town was rebuilt on higher ground.

One of the relocation's masterminds, environmental engineer Jamie Simmonds, said the project succeeded because residents were given a way to keep their community together.

He said offering people money to abandon their homes is essentially cutting them a cheque to bugger off.

"If ... there are situations where the community can sit there and say: 'there is a piece of land right there that I would gladly march my house up to, and you didn't even talk about it?'.

"Mate, they're going to come at you with pitchforks."

Families should be assigned independent support

Grantham's local council provided new land for a land swap, and there were resources from state and federal governments as well as public donations.

People still had to suss the financing for their own builds, but Simmonds said each family had a case manager and a huge amount of support.

"Banking, finance, tax, insurance.

"And because we became their trusted confidants, we would sometimes help organise stuff for them - in line with ... other agencies."

Lawyer Barrett Ristroph worked with the indigenous people of the remote Alaskan community of Newtok.

They are in the process of relocating to safer ground on a nearby island as their tribal homeland is being inundated by the sea.

She agreed people needed independent help.

"I think it would be helpful to have an ombudsman to be there to be able to guide a community through the process and [come] to consensus on what they want to do."

Get organised, appoint good leadership

Ristroph said those who have been flooded out need to learn the lesson of Newtok: get organised, appoint leaders, and lobby hard.

"What Newtok had going for them was from the very beginning they were coordinated, they all agreed they wanted to move to the same place.

"They had a very compelling case, they were able to get the right people to be able to put in the word to Congress.

"They used all the resources they had."

Community and consensus crucial

The Dutch have a long history of using engineering to hold the sea at bay.

Sian John works for Netherlands engineering firm Royal HaskoningDHV, and has extensive experience working on shoreline management in Britain.

She said conversations about whether some coastal residents may have to relocate began there 30 years ago - with decisions tending to come down from on high rather than fully involving the community.

"There was mixed reaction from communities, court cases, a lot of resistance.

"There's been a lot of dissatisfaction."

In recent years she has worked extensively with Thames-Coromandel District Council on its shoreline management plan, where more than 150 public consultations and meetings were held.

Meanwhile, one of her colleagues has been contracted by Hawke's Bay business owners to come to the region and give advice about flood protections, and what to do next.

Cristina De La Vega-Leinart from the the University of Greifswald in Germany said you have to gather as much data as you can about the risks, and then have proper consultation with locals.

"The best approach is of course when you find a way to engage with everybody, and find a way to build consensus about what has to be done.

"And consensus might mean that you have to give up certain areas to protect others."

The New Zealand government said it should have details on which weather-hit areas were high risk within three weeks, with Cabinet decisions about rebuilding to come after that.

A full nationwide draft plan for how to do managed retreat is expected to be released for public input before this year's election.