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Published: 2001-07-16 00:00:00

Many Waikato farmers are achieving better environmental performance with their farm dairy effluent treatment systems as more move to land based disposal.

That’s the finding of Environment Waikato’s monitoring of farm effluent systems over the past season. Programme manager Mark Davenport told last week’s Regulatory Committee meeting that systems have been inspected annually since 1993 by contractors.

In the last season 5094 systems were surveyed – 230 fewer than the previous year and 328 fewer than the year before. The reduction in numbers was due to the trend to larger and amalgamated farms as well as the growth of dairying in the South Island where a large number of herds had moved.

More farms were now using land disposal as farmers realised the value of effluent as fertiliser and the incentive of having land disposal as a permitted activity without the controls needed for water systems. The number of farms moving to land irrigation was likely to fall off as it was not practical on some farms because of land contour or soil type.

Some systems would continue to discharge to water, with a close watch on developments in this area, he said. These included full scale trials of advanced pond treatment systems at Kiwitahi and Hautapu and a study of on-farm wetland nutrient removal, both undertaken by NIWA.

Systems were graded as good, satisfactory and unsatisfactory with a fourth marginal grade removed as standards of systems and management improved. The past season showed about 75 percent of systems now rated good with only 25 percent unsatisfactory. The previous year about 35 percent rated unsatisfactory.

Mr Davenport said the result was pleasing as operating land irrigation systems was more management and equipment intensive than pond discharge systems.

Six systems were seriously non-compliant, with one being served an infringement notice and several other enforcement actions taken through following up complaints.

Opportunities existed to better align inspections with increasingly industry and farmer-driven environmental management, and these would be followed up this year, he said.