Canterbury’s Waimakariri River is an unpredictable, braided river that has the potential to rise to extreme levels.
The Waimakariri Flood Protection Project is a massive undertaking that began more than 13 years ago when the plans were first mapped out in 2006.
The project will protect part of Canterbury from flooding, which has the potential to cause more than $8 billion worth of damage, through the improvements to the primary stopbanks, and the development of a comprehensive secondary stopbanking system, giving Cantabrians peace of mind.
Major flood events have struck Canterbury multiple times during the past 150 years.
High river levels breached the Waimakariri River stopbanks and submerged various parts of the region. The most recent major flood was in 1957 at Coutts Island, near Belfast.
The rock armour protection work along the banks of the Waimakariri River required more than 260,000 tonnes of rock.
The stopbank work was meticulously planned to take place in stages during the project.
The project has seen the upgrade of 35km of primary stopbank, and the construction of a 25 km secondary stopbank.
Native vegetation protection and enhancement - McLeans Island & Halkett
Rare native herbs, mosses, shrubs, and trees such as Kōwhai were identified and mapped, and stopbank alignments and construction access routes were chosen to avoid these areas. Stock exclusion fencing was built, and additional native plants were planted to further protect and enhance these areas.
McLeans Island and Crossbank carpark and cycleway development
Native grasses, scrubs, and trees were planted around the newly developed carpark, cycleway entrance, and stopbank access ramp.
Sanctuary Wetland and Engelbrechts Rock Groynes
The 45-hectare sanctuary is an established wetland area at Coutts Island, located between the riverbank and primary stopbank. The wetland has substantial native plant and fishery values and has an ongoing programme of weed and animal pest control, native planting, and improvement of public access by cycleway/walkway development. The Waimakariri Flood Protection Project assisted this with rock riverbank erosion protection, water level control, and riparian native planting.
Smiths Creek - Kaiapoi Island
This 1km spring-fed creek is located between the stopbank and riverbank and has high native and sports fish values. The Waimakariri Flood Protection Project enhanced the creek with rock erosion protection and removal of weed willows, which enabled follow-up native riparian planting. The project also constructed a nearby carpark to improve and manage recreational access for the local area.