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Good practice Imported

Ōtākaro Avon River Corridor — Post-Earthquake Managed Retreat into a Floodplain Green Spine

New Zealand · Christchurch · See the New Zealand profile · See the Christchurch profile

Evidence: Observational / pre–post Top 40% 47/100 · Ask Evidence Copilot about this practice

After the 2010–11 Canterbury earthquakes, the Crown bought out roughly 8,000 liquefaction-hit properties along the Ōtākaro/Avon River and is converting the 600-hectare red zone into an 11 km green corridor with new wetlands treating stormwater from ~25,000 properties.

8,000+ properties
Properties bought out (city-wide red zone)
~600 hectares
Corridor area
11 km
Corridor length
80 hectares (31 ha + 49 ha)
Constructed wetland area treating stormwater
~25,000 properties
Properties served by constructed wetlands
~600 NZD million
Initial estimated buyout cost

Details

Maturity
Scaling
Promoter
Christchurch City Council, with Regenerate Christchurch and Toitū Te Whenua (Land Information New Zealand)
Period
2011–2023 land acquisition and governance transfer; regeneration ongoing
Keywords
disaster recovery, floodplain management, urban planning, ecological restoration

Context

The 2010 and 2011 Canterbury earthquakes caused severe, repeated liquefaction along the Ōtākaro/Avon River in eastern Christchurch, where more than 5,000 households once lived; the land was voluntarily bought out by the Crown as part of a wider city-wide red-zone buyout of over 8,000 properties.

Activities

Governance passed through CERA (2011), then Toitū Te Whenua/LINZ, then Christchurch City Council (completing June 2023). The adopted Regeneration Plan reimagines the corridor as an 11 km 'green spine' up to 150m wide, including an engineered 31-hectare wetland plus a further 49 hectares elsewhere, together treating stormwater runoff from roughly 25,000 properties.

Results

The plan followed public consultation gathering over 5,000 community ideas, in which a Nielsen survey found 83% of respondents prioritised groundwater quality and 72% prioritised river/stream/lake/wetland water quality; volunteer replanting events continue the corridor's build-out.

Conclusions

This is a large, still-unfolding programme: no independent figures for total carbon sequestered, species recovered, or final project cost were found, and full ecological build-out will take years beyond the 2023 governance handover.

Implementation
Indicative cost
Very high (> €5M)
Time to results
Long (> 3 years)
Staffing & skills
Christchurch City Council, Regenerate Christchurch, Toitū Te Whenua (Land Information New Zealand)

Conditions for success

  • Documented 12-year, multi-agency governance sequence with a clean ownership handover
  • Public consultation gathering 5,000+ community ideas shaping the plan

Common failure modes

  • No independent figures yet for total carbon sequestered, species recovered, or final project cost
  • Full ecological build-out will take years beyond the 2023 governance handover

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Data sources

Where this practice's information was retrieved from, and when.

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