Why are we measuring this?
Our braided rivers are vital ecological corridors that connect the mountains to the sea (ki uta ki tai), providing essential habitats for indigenous biodiversity.
Globally, braided rivers are rare. You would need to travel to Alaska, Canada or the Himalayas to find similar examples of what we have right here on our doorstep. Two thirds of Aotearoa New Zealand’s braided rivers are in Waitaha Canterbury- a key feature of our region's natural character.
There are seven alpine braided rivers that contribute about 88 per cent of the freshwater flows within our region. These are:
- Waiau Toa/Clarence
- Waiau Uwha
- Hurunui
- Waimakariri
- Rakaia
- Rangitata/Rakitata and;
- Waitaki.
There are three main hill-fed braided rivers: Rakahuri/Ashley River, Waikirikiri/Selwyn and the Hakatere/Ashburton River, with other smaller rivers that are also braided or are fed by braided river networks.
An important biodiversity function of braided rivers is the provision of nesting and feeding areas for birds. Braided river birds, many of which are endangered, rely on the gravel islands formed by the mobile river braids to lay eggs and rear chicks safely from introduced predators and disturbance. Many different birds also use river braids for feeding. The structure and arrangement of gravels and vegetation covering braided riverbeds impact the availability and suitability of nesting and feeding river braid habitats.
The intactness and health of the biodiversity associated with braided rivers plays a vital role in determining their naturalness. Equally important is their ability to maintain their natural processes and patterns. Examples of this include a braided river's ability to move across its braidplain and the need for flushing flows to occur in rivers. These natural processes and patterns, along with essential habitats for native biodiversity, have deteriorated over time due to invasive weeds and pest animals, water abstraction, land development, river control works and encroachment, climate change, and damage from recreational use.
How do we measure the result?
For braided river bird habitat, ~59 braided riverbed and margins across Waitaha Canterbury are classified according to the presence or absence of water, gravels and vegetation ground covers. This includes classifying the depth, type, and density of each of these ground covers respectively. We use automated remote sensing techniques to assign computer-generated ground cover classes to the areas of braided riverbed and margins and then calculate the area of ground cover for each class.
We repeat our remote sensing analysis every 10-12 years because braided riverbed ground cover classes, and useable braided river bird habitat areas in Waitaha Canterbury, change over time depending on gravel management activities and flood and erosion processes. The total area of useable habitat (hectares) overall is calculated and reported for the ground cover classes that make up feeding and nesting areas for braided river birds. The totals for different ground covers for each river are in the report Monitoring the extent of braided river cover classes in Canterbury – a 2012 and 2024 comparison (PDF. 11.7MB). High and dense vegetation classed areas are not suitable braided river bird habitat. Regular bird surveys taken across many of our braided rivers complement this work, helping us understand bird presence in relation to available habitat.
For natural character values, our braided river monitoring programme applies in-field and remote sensing methods to monitor vegetation and habitat diversity for 25 rivers across the region – two rivers are monitored each year over 10-year cycles, starting from 2024. After 10 years we repeat the first two rivers and begin to assess change and report on natural character values. Results for the first two rivers, the Waimakariri River and Poulter River, are reported in the Braided river monitoring report – 2024/25 Environment Canterbury Science Summary (PDF, 13.6MB). Results for the second two rivers, the Rakaia River and Wilberforce River, are reported in Ecological Monitoring on the Rakaia River Braidplain, Canterbury. 2026. Data for surveyed rivers is also available on the National Vegetation Survey (NVS) Databank managed by Bioeconomy Sciences Institute New Zealand.
What work have we undertaken to contribute to this outcome?
Regional councils are directed by law to set policies and rules in their resource management plans for preserving the natural character in their region. This includes a range of roles and responsibilities when it comes to managing braided rivers:
- regulation
- land management
- biodiversity and natural character
- biosecurity
- flood protection, and;
- state of the environment monitoring.
The Canterbury Land and Water Regional Plan and a number of river regional plans provide protections for ecosystems and habitats in the seven major braided rivers. We have also implemented a comprehensive state of the environment monitoring programme for Canterbury’s braided rivers.
We support a range of braided river projects including:
- weed control in the upper Waimakariri catchment
- education and community engagement around the Hakatere/Ashburton River
- the Hurunui and Waiau Braided River Birds Programme to enhance islands, trap predators, monitor birds and improve breeding success
- the Braided River Revival initiative, restoring river health through vegetation resilience projects.
We also support and work closely with the community via Braided River Aid (BRaid), an umbrella group that aims to protect, enhance and restore braided river ecosystems through co-operation and partnerships with iwi, individuals, schools, community groups, commercial and recreational stakeholders, and government departments responsible for river management.
The Canterbury Braided River Flagship Programme provided substantial funding to enhance the health of the braided river ecosystems in upper catchments of the Rakaia and Rangitata/ Rakitata Rivers.
Our aim is that the mauri (life force) of braided rivers is revived ki uta ki tai, with collective action aligned at a landscape scale to achieve this.
Who else plays a role?
There are numerous Trusts, community organisations and volunteer groups who play a significant role in braided river management.
Project River Recovery is a restoration programme led by the Department of Conservation/Te Papa Atawhai making contributions to braided river ecosystem protection in the Upper Waitaki Basin. Projects underway include landscape-scale weed and predator control, research into new predator control methods, invertebrate fauna surveys, long-term bird population monitoring and education programmes.
BRaid’s list of river care groups shows others who play a role across Waitaha Canterbury.
How does this link to our Climate Action Plan?
This measure is directly linked to Action B in our Climate Action Plan Te Mahere Huringa Āhuarangi: Continue to maintain and improve established flood and river resilience measures. This action reiterates Canterbury Regional Council’s commitment to reduce the risks of flooding to communities through continued maintenance and improvement of flood and river resilience measures, including forestry, as set out in the 2024 30-Year Infrastructure Strategy.
Managing flood risk and managing braided river ecosystems are closely connected - the gravel management and flood and erosion processes that shape useable bird habitat are the same processes Action B works to manage, including through nature-based approaches to flood and erosion mitigation and continued support for Braided River Revival strategies. As climate change increases the frequency and severity of heavy rainfall, flood and river resilience work that integrates ecological outcomes becomes increasingly important for sustaining braided river habitat alongside community protection. F1 helps show the difference Action B is making over time.
Find out more about our Climate Action Plan.
Where can I find more information?
Learn about our work to protect our braided rivers.
Read about the landscape values of Waitaha Canterbury.
The Braided River Bird Survey Tool on Canterbury Maps.
Download the 2024/25 results for F1: Extent of habitats* (and natural character) of braided rivers is increasing (PDF file, 444KB)
