In the early 1980s, the government built what is now known as the Kerikeri Irrigation Scheme to support the Northland town’s growing horticulture industry. The 340-Member co-operative offers both commercial and non-commercial water supply sourced from the Manuwai and Waingaro reservoirs.
Horticulture has been a feature of Kerikeri’s economy and environment since the 1920s when the first citrus orchards were established, explains Manager Tony Corcoran.
“The moisture-holding capacity of the volcanic soils in the district is low and the summer droughts can be long so that even with an annual rainfall 1,800mm, supplementary irrigation is necessary for the consistently high quality fruits,” he said.
The infrastructure was built by the Ministry of Works and started delivering water in the early 1980s.
“In 1990, local horticulturists and farmers formed our co-operative, Kerikeri Irrigation Co Ltd, and acquired the assets from the government.
“Today, we have 340 shareholders, plus nearly 1100 non-commercial connections, who are supplied with water from two storage reservoirs.”
The scheme supports:
- Horticultural land (2,300 hectares)
- Agricultural land (350 hectares)
- Lifestyle blocks
- Commercial Users
Raw bulk water for town supply
Irrigation is now the foundation of the horticultural sector, the town and the region.
Tony Corcoran points to the 2016 KICL Economic, Social and Environmental Impact Report shows KICL contributes more than $100 million per annum to the region’s GDP and employs more than 1,300 FTEs.
“The report also looked at KICL’s environmental impact and found that the scheme had improved total flows and drought flows in a majority of the catchment’s streams and rivers.
“Irrigation isn’t a contentious issue here because its value is recognized and understood. Communities need diversity and KICL has delivered it. The whole value of the community has been lifted on the back of horticulture and irrigation.”
The irrigation scheme is large. The combined scheme storage is 12 million m³, compared to Whangarei City’s Whau Valley dam, which stores 1.9 million m³. Kerikeri, the largest urban centre in the Far North District (FNDC) is a customer of the scheme.
Tony says the main reservoirs are sited high in the catchments to minimise diversion and spillway costs, to enable a largely gravity-fed irrigation supply and to lessen the impact on the local environment.
“One of the scheme’s major advantages is the way it harvests the water in the high rainfall times and stores this in its reservoirs for distribution during drier periods. This has reduced the pressure on the local rivers and streams for the taking of water for irrigation purposes and helping to protect their natural flows.”
Tonkin & Taylor, the scheme’s original engineers from the 1970s, were engaged to review the Kerikeri irrigation scheme assets and provide feedback.
“Their report contained suggestions for developing an asset management plan to future proof the scheme’s infrastructure for the next 35 years,” said Tony.
“There is no doubt that the Kerikeri Irrigation scheme remains a significant regional asset with a long history of very efficient and frugal operation. The scheme faces a range of risks that will increase with time but these can be reduced by improving existing asset management practices.
“The report identified a prioritised list of action items that are required to manage, maintain and enhance the scheme well into the future.”