The second stage of a major South Canterbury irrigation scheme, Central Plains Water, will be finished by September 2018 after unanimous support from shareholders.

The first stage of the project began last August and, when completed, the scheme will irrigate 50,000 hectares of dairy, horticulture and stock land between the Rakaia and Waimakariri Rivers. However, a third stage has effectively been covered off in the second stage, with plans also to extract water from the Waimakariri River shelved and underground pipes favoured over the extension of the scheme's canal system.

CPW shareholders buy rights to the amount of water they want from the project, and at a special meeting for Central Plains Water (CPW), the second stage, which will cover development of 20,000 hectares, got the unanimous support of over 200 shareholders, CPW said in a statement.

The total project is estimated to cost $400 million, with $250m to be spent on the second stage. CPW shareholders have contributed $90m, while government-funded Crown Irrigation Investments has committed "significant support" from its revolving fund to kick-start irrigation schemes, for this stage of the project.


The Ministry for Primary Industries' Irrigation Acceleration Fund has also contributed, and Selwyn District Council provided a short-term loan, with more lending from ANZ Bank and Westpac.

The government invested $11.8m in the first stage of the project through Crown Irrigation Investments and the Irrigation Acceleration Fund, and $3.5m for the early investigation phase of stage 2. In May, Primary Industries Minister Nathan Guy announced $6.6m in further funding to help develop the second stage of the project.

CPW chief executive Derek Crombie said Waimakariri River water was no longer needed as it could be sourced from Lake Coleridge. The project will use a buried pipeline and will lay 21 kilometres of main pipe, linking to 184km of pipes to take water to the farm gate, while 14 pump stations will be built.

"Very little extra capacity has been built into each pipeline, so it is imperative that those wanting to purchase further shares do so now, otherwise it could be too late. We cannot retrofit extra capacity," Crombie said. "Across all the three stages, mixed farming systems (dairy, sheep and beef, arable including some dairy support), will be the predominant land use."

Crombie said the scheme would provide significant environmental benefits by replacing current groundwater abstraction with river water. The first stage replaced 75 per cent of the groundwater abstraction in that area, with bore levels remaining steady even during a drought period, and the same is expected in the next stages, he said.

CPW says the full scheme is expected to create over 1,000 new jobs and add more than $1 billion annually to the economy.