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Published: 2001-05-16 00:00:00

Environment Waikato is to review consents allowing Wallace Corporation to irrigate wastewater after an increase in nitrate was detected in monitoring bores under the irrigation farms.

The company had applied to increase the discharge when they purchased the Glenburn Farm property, and were given permission in February last year. Monitoring bores were installed and the predicted environmental effect was considered minor at the time, Resource Officer Barry Campbell told the Committee.

However subsequent monitoring of the five shallow groundwater bores had shown the average groundwater nitrate had increased greatly, far in excess of the predictions. The company had complied with neither the former nor the changed load limit.

The company has advised Environment Waikato that it was applying about 360 kg per hectare when the limit was 300 kg, however the Council considers that the excessive loads would not explain the significant increase in nitrate levels.

A review of consents was also sought for discharges onto the Park/Auchaenhaen farms. The Committee heard there had been persistent non-compliance with some consent conditions, particularly hydraulic application rates and nitrogen application rates. Some rates were almost double the consented amount and were alarming to Council staff.

Action was underway by staff to ensure compliance with conditions, but there was reasonable doubt that nitrate levels in the groundwater would reduce to more acceptable levels with the present conditions.

The original consent contained some conditions which were not appropriate now, and staff wanted to change conditions to make them consistent with present New Zealand irrigation guidelines. Mr Campbell said the two consents needed to be reviewed as quickly as possible.

The company opposed the recommendation for a review, saying no-one was likely to be adversely affected as the average nitrate level was well within stock drinking water standards and all water for human consumption was treated to reduce nitrate levels. It offered to treat any neighbour’s drinking water found to exceed human drinking water standards as a result of their irrigation activities.

The company said that The problems were not the conditions but management of them. Restrictions on the application would be unwarranted and increase the cost of irrigation considerably. A professionally prepared irrigation plan was underway and should be ready for the next irrigation season, so the company proposed deferring the review until October.