Ministry opposes farm plan
A primary school surrounded by dairy farms risks having its drinking water contaminated if a bid to increase cow numbers goes ahead, the Ministry for Education says.
The agency has opposed a resource consent application to expand a farm near Winton because of what it said was a potential health risk to staff and students at a nearby school.
It is rare for the ministry to oppose such an application on health grounds.
The applicant, Woldwide One, wants to add around 260 cows to one of its five farms. The farm in question is about 2km upstream of Heddon Bush’s school, a small, rural primary school with about 60 students. The school’s drinking water comes from a 15m deep bore.
Ministry officials met with the farm’s manager, Abe de Wolde, last week.
The primary concern is nitrate levels, which have been steadily rising in some rural areas as a consequence of dairy farming expansion.
Testing shows bores around Heddon Bush School already have high nitrate levels, which in some cases breach the maximum allowed under national rules for protecting human health.
In its submission opposing the application, the ministry provided a memo from two hydrogeologists, which argued the school’s water could deteriorate if more cows were added to the farm.
‘‘Cumulative effects from intensification of farming in the area is likely to impact on groundwater quality,’’ it said.
‘‘Of specific concern to the ministry is the potential effect of nitrates entering the drinking water supply and potential impact on human health.’’
It also referred to the ‘‘lag effect’’ – it can take many years for nitrogen to filter into groundwater, meaning current water quality may not reflect current land use.
It also raised the threat of other contaminants, such as E coli, entering the water supply. E coli poses a more direct risk and can lead to diseases such as campylobacter and cryptosporidiosis.
The area’s surface water quality is highly degraded, and among the worst in the country.
Poor water quality has been blamed for the collapse of a nearby trout fishery, and nearby streams rate poorly for various water quality measures.
Woldwide One argued the nitrogen load from the farm would decrease, not increase, based on modelling from Overseer, the widely used farm management software program.
Abe de Wolde said the farm had been operating for more than two decades, and its environmental performance had only improved over time.
‘‘We have modelled the nitrogen loss for that farm, and it has come back at 16kg nitrogen per hectare, which is lower than what it had been before,’’ he said in an interview.
‘‘It is similar to sheep farms in the area, and the farm has been there since 1992.
‘‘During that time it has had a higher loss per hectare than it has now, because mitigation measures lower it from 17kg to 16kg.’’
He said his discussions with officials had been positive, and he did not believe there was a reason for the school to be concerned.
‘‘The water quality at the school ... as far as we know there have been no issues, and there is water purification at the school as well.’’
The de Woldes have won awards for their environmental practices.
The school’s principal, Esther Hamilton, declined to comment.
Public health officials have also raised concerns about the health impact of dairy farming in the area.
In its submission on the consent application, Public Health South – part of the Southern District Health Board – highlighted several health risks that would need to be addressed should the consent be approved.