Guidelines approved for Christchurch's move to adapt to sea level rise

Thursday, 7 April 2022

Christchurch City Council will start climate change planning in Whakaraupō Lyttelton Harbour in spring.

Whakaraupō Lyttelton Harbour will be the first area in Christchurch to go through climate change planning as the city council works to tackle the effects of rising sea levels.

Christchurch City Council on Thursday approved guidelines for adapting existing areas following extensive consultation carried out late last year.

It will consider five options when adapting areas to cope with the effects of climate change, including retreating from coastal areas and trying to keep the water at bay by building seawalls or stopbanks.

Continuing to live in areas is another option, as is living with the hazard while adapting buildings and infrastructure to cope. Not moving into the way of the hazard in the first place is another option, but that is too late for some areas.

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Southshore residents support new plans for dealing with the risk of flooding or erosion due to predicted sea level rise. (First published October 21)

Scientists predict New Zealand will experience about 30 centimetres of sea level rise by 2050, 50cm by 2075 and 1 metre by 2115.

A coastal hazards assessment conducted for the council by Tonkin and Taylor indicated a 1.5 metre sea level rise would result in about 26,500 properties across the city and Banks Peninsula experiencing coastal flooding, erosion and rising groundwater.

Instead of tackling issues city-wide at the same time, the council decided in 2020 to separate the city into seven groupings covering 23 communities.

Christchurch is a low-lying city, vulnerable to the impacts of sudden storms and gradual changes to the shoreline and tides.

It will start with the Whakaraupō Lyttelton Harbour area, which includes Charteris Bay, Tedding, Allandale, and Governors Bay.

The council on Thursday also appointed a coastal panel, which would be made up of community and rūnanga representatives, to work with the council throughout the process.

Council head of planning and consents John Higgins said the process would begin in spring.

An earlier start was anticipated, but the high rates of Covid-19 created challenges for a process that involved important face-to-face meetings with rūnanga, the coastal panel and the wider community, he said.

The process was expected to take about 18 months.

No decisions have been made yet on the next area to go through the process.

The last time the council tried to tackle the impact of sea level rise, in 2015, it triggered widespread outrage. The issue was thrust upon communities as part of a fast-tracked district plan review forced on the council by the Government.

Following the public outcry, the Government allowed the council to deal with the impact of climate change through its normal processes.

This time the council is taking time to consult widely before developing any proposed changes.

Cr Celeste Donovan said coastal communities were still recovering from the earthquakes, and they wanted to see the completion of earthquake repairs before adapting to climate change.

She said it was important the council learned a lesson from previous approaches, and it needed to make sure it was working alongside communities this time.

Cr Mike Davidson said a top-down approach did not work, nor did a bottom-up approach. It was only by working together that you get the best outcome, he said.