A Mangakino dairy farm has been granted a 10 year resource consent by Environment Waikato to take water from two streams in the area for pasture irrigation.

Eastnor Farms Ltd currently owns a dairy farm on Sandel Road in Mangakino with a consent to take 1,440 cubic metres per day of water from the Otamatahae Stream since 1999. It now wants to irrigate the entire farm (200 hectares) using water abstracted from two large streams on the north and west of the property.
Two submissions were lodged with Environment Waikato from Fish and Game New Zealand, Eastern Region and Mighty River Power.

The applicant said movable sprinklers designed to irrigate 25 hectares of land per day would be used and an existing intake structure in the bed of the Otamatahae Stream would be relocated downstream, with a new intake structure added.

The applicant said that as a result of consultation the intake structure in the Otamatahae Stream could be relocated downstream and abstraction could stop before the trout spawning season through to October, when migration for trout was over. Abstraction could be reduced to 12 hours a day when flows in the Otamatahae Stream or the unnamed tributary downstream of the intake structures fell. Abstraction would stop entirely when flows fell to lower levels.

He said the cost of permanent measurement structures and their maintenance was too high and there were difficulties in installing permanent flow recording instrumentation in the streams.

Mighty River Power was concerned about the effect an exceedance of 10 percent of the one in five year low flow (Q5) had on its risk management, the loss of renewable energy, insufficient consideration of efficient use of water and contribution of the proposed abstraction to the growth of blue-green algae.

Fish and Game New Zealand, Eastern Region was concerned about effects of water abstraction on trout spawning habitat, juvenile trout rearing habitat and adult trout, increased nutrient runoff, precedent setting and cumulative adverse effects.

Granting the consent, the Committee added the request that water would not be abstracted for more than 12 hours a day during critical periods. The Committee decided that it was appropriate that a habitat protection level of 85 percent be applied and an in-stream minimum flow was required.

Flows in the Otamatahae Stream needed to be accurately recorded and flows be measured at the existing take. Abstraction should cease when flows reach the levels specified, it said. It was important that the ‘cut-off’ conditions remained to ensure that the instream minimum flow requirements were maintained at all times.

More nutrients could potentially be leached to groundwater as a result of the irrigation because of either increased stocking rates or increased nutrient outputs from the existing stock numbers. The applicant would be strongly encouraged to adopt a formal nutrient budget approach, it said.

The Committee found adverse effects of the proposed activities on the environment and other users of the water bodies would be minor, the activities were discretionary and were generally consistent with Environment Waikato Plans and the Resource Management Act.

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