Our story.
Switching irrigation water sources to provide a more environmentally sustainable solution for Canterbury’s agriculture.
Over the past century, the Canterbury region has developed as one of New Zealand’s most important agriculture, cropping, and seed production regions, proudly underpinning Canterbury’s identity and the nation’s economy.
Our world-leading food and fibre products are internationally sought after and with New Zealand’s population predicted to grow to just under six million by 2030, this demand will only increase. To meet that demand, farmers and growers need access to irrigation to enable the production of food and fibre our population will require. Without this, as demand increases prices will also increase, resulting in more imports to fill the food gaps. Water is the limiting factor.
Even the best farming systems are limited by soil moisture and the reliability of seasonal rain does not suffice in scaling up food production. Our rural areas that sit at the foot of the Southern Alps are likely to become some of the country’s drought hotspots, having already experienced two seasons of droughts in 1988/1989 and 1997/1999.
The Central Plains Water (CPWL) story began in 1883 with talk of establishing an irrigation scheme to service farms on the Canterbury Plains, with the first approach to central Government made by the then Malvern County Council. However, it wasn’t until 51 years later that the idea gained significant momentum.
Rakaia River Intake Stage 1.
Located within the Selwyn District Council boundary, between the Southern Alps, the Waimakariri and Rakaia Rivers, the first stage of the scheme the Rakaia River Intake was the largest irrigation project ever undertaken in the South Island. Opening in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents the project saw 13 bridges, 12 pump stations, and 130 kilometers of underground pipeline constructed. Successfully delivering a 50-70% reduction in the abstraction of groundwater from shareholders switching from bores to alpine river water to replenish the aquifers and lowland streams.
In early 2014, the first stage of construction, the Rakaia River Intake saw irrigation delivered to 23,000 hectares of productive farmland in an area bordered by the Hororata and Rakaia rivers, introducing 300 million cubic metres of low-nutrient alpine water into the catchment to replace groundwater abstraction.
- The Rakaia River intake is located approximately 8 kilometres downstream of the Rakaia Gorge Bridge.
- Before entering the main headrace, the intake water is conveyed into flow control structures and sediment retention ponds and passes through a fish screen.
- A 17-kilometre-long canal delivers water from the Rakaia River into a piped distribution network.
- The terrace headrace was constructed with an engineered fill embankment ‘bench’ rising to around 15 metres before water enters a bench cutting into the terrace race for the remainder of its length.
- The headrace travels north for approximately 10 kilometres through to Leaches Road, following the most practical route through farmland.
- A piped reticulation system, controlled by a central computerised control system, providing water to the farm gate at a pressure equivalent to a head of 40 metres.
- Since the completion of this stage on 1 September 2015, the scheme has delivered water 24 hours a day, seven days a week during peak irrigation season.
The Rakaia River Intake stage of the scheme opened in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents.
The Rakaia River Intake stage of the scheme opened in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents.
The Rakaia River Intake stage of the scheme opened in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents.
The Rakaia River Intake stage of the scheme opened in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents.
The Rakaia River Intake stage of the scheme opened in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents.
The Rakaia River Intake stage of the scheme opened in 2015 with an investment of $157 million in construction and $30 million for the design and resource consents.
Rakaia River Intake Stage 2.
Located between the Selwyn and Waimakariri Rivers, with a total construction cost of $182 million stage 2 was the largest dryland conversion in the scheme, significantly helping to alleviate pressure on the aquifers critical to Canterbury. Stage 2 saw the installation of 12 pump stations, 3 pressure-reducing stations and a 23 kilometre long, subterranean large-diameter (2.5m) Glass Reinforced Plastic (GRP) pipeline.
- With an area approximately twice the size of stage 1, stage 2 provides the infrastructure for shareholders to switch from groundwater to low-nutrient alpine-sourced water to replenish flow in the lowland streams.
- Supported by consented and stored water from Lake Coleridge, stage 2 is entirely an underground gravity-fed pipeline distribution network utilising run-of-river water from the Rakaia River, supplying pressurised water to the farm gates – no on-farm water pumping.
- Since the completion of stage 2 in 2018, an additional 20,000 hectares of irrigated land has been achieved between the Selwyn and Waimakariri Rivers.
The largest dryland conversion in the scheme the second stage takes water from the end of the existing stage 1 canal. Fully underground servicing 20,000ha of farmland.
The largest dryland conversion in the scheme the second stage takes water from the end of the existing stage 1 canal. Fully underground servicing 20,000ha of farmland.
The largest dryland conversion in the scheme the second stage takes water from the end of the existing stage 1 canal. Fully underground servicing 20,000ha of farmland.
The largest dryland conversion in the scheme the second stage takes water from the end of the existing stage 1 canal. Fully underground servicing 20,000ha of farmland.
The largest dryland conversion in the scheme the second stage takes water from the end of the existing stage 1 canal. Fully underground servicing 20,000ha of farmland.
Waimakariri River Intake, Sheffield.
Physically separate from the first two stages of the irrigation scheme, covering an approximate area of 4,600 hectares the Waimakariri River Intake, Sheffield commenced operations in November 2017. Supplying consented irrigation water from the the Waimakariri and Kowai Rivers (which are subject to similar low flow restrictions to those applying on the Rakaia River) the smallest of the three stages had a construction cost of 42 million dollars. Construction included a 2.5MW pump station, 37 kilometres of pipeline, and a 2 million cubic metre storage pond helping to provide resilience during periods when run-of-river abstraction is restricted.
- The river intake is located on the Waimakariri River opposite the Kowai River.
- Water from the Waimakariri River enters the intake channel where it passes through a rockfish screen and onto the sediment retention pond.
- The pump station transfers up to 2 cubic metres per second of water 80m vertically into an open channel supply race, through three concrete drop structures to slow velocity before it enters the 1.6m inlet pipe for the last kilometer to the storage pond.
- The Sheffield storage pond is approximately 100 acres in size and holds 2.15 million m3 of water. The pond is lined with 300,000m2 of high-density polyethene to stop any losses through the mainly gravel pond floor.
The 2 million cubic metre reservoir is a lynchpin of the Sheffield stage, which introduced surface water irrigation to farmers in the area for the first time.
The 2 million cubic metre reservoir is a lynchpin of the Sheffield stage, which introduced surface water irrigation to farmers in the area for the first time.
The 2 million cubic metre reservoir is a lynchpin of the Sheffield stage, which introduced surface water irrigation to farmers in the area for the first time.
The 2 million cubic metre reservoir is a lynchpin of the Sheffield stage, which introduced surface water irrigation to farmers in the area for the first time.
The largest dryland conversion in the scheme the second stage takes water from the end of the existing stage 1 canal. Fully underground servicing 20,000ha of farmland.
The road to climate resilience.
135 years after Malvern Country Council made the first approach to central Government, CPWL has realised its vision. We’re now bringing irrigation to the Central Plains of Canterbury, delivering environmental, economic and social benefits to the wider community by increasing Canterbury food and fibre production for local and world markets.
