The river corridor is probably the largest area of managed retreat in an urban centre worldwide. How can our experience inform processes of managed retreat elsewhere? The question is central to this project, which has developed a model of ‘retreat’, ‘relocation’ and ‘re-imagining’. Re-imagining asks how can the land be re-used for projects that further lower environmental and social risks.
Historical Data
This information is drawn from work assembled by Chrissie Williams (see interview in Oral Histories) for a report by Regenerate Christchurch (2017).
The first map shows post-earthquake ground surface elevations in and around the river corridor, derived from 2015 LiDAR data, indicating the likely extent – growing over time - of tidal inundation and flooding (see also). This reality will affect the historical pattern of pre-urban vegetation, as summarised in work undertaken by Lucas Associates in the 1990s (ref).
Map 1: Post-earthquake ground surface elevations in and around the river corridor (Orchard 2017).
Map 2: Ecosystems of the lower Avon-Ōtākaro catchment based on "Black Maps" and the Ecosystems Map of Lucas Associates (Lucas Associates 2025).
Taking these two maps together, the third map represents a biodiversity classification of ecotopes in the river corridor based on a hydrosystems approach (Orchard 2017). The Regenerate report (page 11) mentions some flagship species that could be the basis of restoration efforts in these ecotopes: kūaka/godwit in the estuarine; kereru/wood pigeon in the terrestrial; īnanga/whitebait in the aquatic.
Map 3: Biodiversity classification of ecotopes in the river corridor based on a hydrosystems approach (Orchard 2017).
References:
Lucas Associates (2025) Christchurch ecosystem map. Available at: https://www.lucas-associates.co.nz/christchurch-banks-peninsula/ecosystem-map/
Orchard, S. (2017) Integrated Assessment Frameworks for Evaluating Large Scale River Restoration. Report prepared for the Avon Otakaro Network, Christchurch, NZ. ISBN 978-0-473-39796-8 http://bit.ly/Integrated-assessment-frameworks
Regenerate Christchurch (2017): Ōtākaro Avon River Corridor Ecological Restoration Indicative Business Case.