Facts needed in Havelock North response

A focus on science and proven solutions is needed in the response to the Havelock North water crisis, says IrrigationNZ.

“IrrigationNZ is very concerned, as is everyone else, about the situation in Havelock North. However, we are surprised by some of the accusations now being made around intensive livestock and irrigation, particularly as the area surrounding the water supply well is dominated by orchards, cropping and low intensity livestock.”

“Before jumping to conclusions we first must understand the facts. A thorough inquiry will establish how groundwater in the area has become contaminated but this will take time. In the short term we should be moving towards best practice when it comes to protecting public water supplies from contamination,” says Andrew Curtis, IrrigationNZ CEO.

Fact 1;

Pathogen contamination almost always results from a point source or a preferential flow scenario.

“The issue will likely be either a preferential flow scenario down the side of an old well case (particularly around older bore casings), a poorly constructed or sealed well head or backflow (contamination making its way directly into bores). Another scenario could be point source from the stock piling of manure. During periods of heavy downpour, contaminants can move through the soil and then there is a risk,” says Mr Curtis.

Fact 2;

Grazing livestock or irrigation are unlikely to be the cause.

“The Havelock North end of the Heretaunga plains is an area of low intensity livestock. Dominated by orchards and seasonal cropping, with sheep grazing in winter there is no dairy or intensive livestock,” says Andrew Curtis.

Livestock grazing is extremely unlikely to have caused this issue – the pathogens don’t make it through the soil, the soil acts as a filter – research work undertaken by ESR has previously shown this to be true.”

Solutions to prevent contamination of groundwater?

Proven solutions include good management practice at both the supply point and any nearby wells.

“Well head protection is essential for all bores and this needs to be better enforced for older bores. Additionally, we need to be looking at requiring back flow protection where applicable. IrrigationNZ has produced guidelines for backflow prevention that are based on international best practice for agriculture. On top of this, the council needs to be managing nearby point sources where, if heavy rain occurs, leaching could result. Basically all wells near public water supplies should be properly protected.”

“A best practice approach to managing the threats to public water supplies needs to be implemented across New Zealand. There will always be risks from avian, ruminant and human sources so we need to be identifying all the contamination pathways. We need to let the experts get on with their jobs and not take cheap shots with un-informed accusations,” says Mr Curtis.

ENDS

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