Irrigation plan for Hurunui

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Irrigation plan for Hurunui
05 April 2006
By ROBYN BRISTOW

A multimillion-dollar irrigation scheme, based on Lake Sumner and the damming of the south branch of the Hurunui River, has been mooted in the Hurunui District.

The scheme could provide irrigation for 39,000ha of farmland in the Hurunui and Upper Waipara catchments, with the possibility of expanding to 62,000ha.

Hurunui Community Water Development working group project manager David Viles said yesterday if the project got the backing of the farming community and negotiated its way through planning processes it could give the biggest stimulus to the Hurunui and North Canterbury economy for a "long, long time".

While MainPower, North Canterbury's power company, was a member of the working group, the focus of the scheme was on irrigation and not hydro-power generation, he said.

MainPower's interest was based on the economic development of North Canterbury and if there was any hydro power potential it would be "minor and indeed an insignificant part of the scheme", said Viles.

The project was still in its infancy and at least five to six years away from becoming a reality "with a following wind", he said.

It aimed to manage water levels in Lake Sumner and harvest excess water from the Hurunui River system, storing some and using some for irrigation. The stored water would be spilled back into the river system to boost the flow when water levels dropped and so irrigation water could be drawn off.

Viles said Lake Sumner fluctuated by several metres owing to a natural restriction where water left the lake.
"We plan to control it better and operate within the tidal range of the lake," he said.
Research indicated that 30 per cent of the time storage was needed to meet the demands of irrigated land in the district.

"A water-storage scheme would give existing farmers more certainty about irrigating and would enable new ventures to start up on the back of access to water," he said.

The unveiling of the scheme follows a three-year search for water in the district by the working group, including the Hurunui Irrigation and Power Trust, Enterprise North Canterbury, the economic development arm of the Hurunui and Waimakariri district councils, MainPower, Ngai Tahu Properties and Eskhead Station where both sites under investigation are sited.

Viles said the desk-top pre-feasibility study by consultants Tonkin and Taylor that had identified the south branch of the Hurunui and Lake Sumner as two sites for further investigation, was funded through a $225,000 grant from the Ministry of Agriculture's Sustainable Farming Fund, matched dollar for dollar by working group members.

Viles said no engineering or technical studies had been done, but depending on the storage option and the river-flow regime chosen, the likely cost for those wanting to get water to the farm gate would be $2500 to $4500 a hectare.

Hurunui Mayor Garry Jackson yesterday welcomed the proposal. He said it was an important project for growing the primary-production sector and the economic well-being of the district.

The council would be taking a much greater interest in the progress of the working party which had worked well as a unit.

North Canterbury Fish and Game environmental officer Jason Holland said his organisation would be concerned about any development on the nationally significant river, which was an important brown trout and salmon fishery.