Don’t let the wreckers damn our dam

As the rally gets underway in Waipukurau….

Don’t let the wreckers damn our dam

An opinion by Federated Farmers Hawke’s Bay provincial president, Will Foley

Last month, Massey’s Dr Mike Joy told a Canterbury audience, “The nitrate toxicity in some waterways is 10 times the safe level already. We have gone from safe levels of 1.9 millilitres a litre, to 3.8ml/l in Canterbury."

With the Tukituki Board of Inquiry proposing a limit of 0.8 milligrams per litre for dissolved inorganic nitrogen, it would seem contradictory, but its draft decision is about a very different limit - what it believes is good for ecosystem health. And on the nitrate toxicity score, the draft National Objectives Framework has set 6.9ml/l as the bottomline and the Tukituki is not even remotely close.

So let’s park Dr Joy and focus on what we all want to achieve for the Tukituki.

That means remembering why we started out in the first place. It was to tackle an algae that’s been with us forever called Periphyton. Everyone agrees it’s a problem so what’s the solution?

We get Periphyton because the Tukituki is a rocky river running warm during summer low flows. Its growth is exacerbated by nitrogen and phosphorus so Hawke’s Bay Regional Council came up with a three-pronged approach hitting phosphorus, managing nitrogen and increasing water flows.

In all the debate since, this environmental solution with strong economic benefits has been parked out of sight.

You can only increase water flow during summer by storing rainwater and that’s where Ruataniwha comes in. This extra water helps to cool the Tukituki during summer while flushing it of Periphyton. That’s been the experience of South Canterbury’s Opuha scheme on a similar river. Another experience is the economic boon Opuha has been to South Canterbury.

Yet during the Board of Inquiry, Dr Joy’s colleague Dr Death, helped to shift the focus off Periphyton and towards the stream life of rivers using a model developed for the Manawatu; a very different river to our Tukituki. Arguably, that’s how a limit of 0.8mg/l entered the minds of the Board of Inquiry, but how many invertebrates found in water doesn’t correlate to any one nutrient.

Ironically, it was Fish and Game’s Corina Jordan who confirmed that while nitrogen and clearly phosphorus have impacts, so does river flow, sediment, light intensity and temperature. The upshot being that there is no straight line relationship between a limit of 0.8mg/l and invertebrate health.

Farmers like me are not in denial because Federated Farmers is okay with having a number, but that number must be an indicator and not chiselled into granite. Especially since that number was derived from a model not validated for the Tukituki River and especially since Dr Death’s use of the Macroinvertebrate Community Index happens to be an indicator itself.

The Hawke’s Bay community needs a solution but the proposed limit of 0.8mg/l is so blunt, it makes Ruataniwha untenable.

The Port of Napier is right to call Ruataniwha a game changer for the entire Hawke’s Bay region. Before Ruataniwha’s viability was compromised we were talking about a quarter of a billion dollar boost each and every year. If 0.8 remains as a hard limit, it not only kills the dam but means the region going forward will become $50 million poorer each year.

Unless 0.8 becomes an indicator it will seriously compromise all the farming we currently have. We’re not just talking sheep and beef but the guys who grow crops, the guys who run orchards, those who milk and even the guys who grow the grapes our region is famous for.

A hard limit of 0.8 means no Ruataniwha leaving us with Periphyton, a worsening economy and increasingly, rivers suffering from ever lower and warmer flows due to drought. If farms convert to forestry we can possibly add sediment to that list. Can anyone tell me what the environmental or community upside is?

Dr Doug Edmeades wrote recently, “the best pieces of advice I was given as a young scientist: ‘Edmeades, I do not give a damn for your opinion what are the facts.” Opinion seems the basis for 0.8mg/l but it is fact that it’s 14 times more stringent than the international standard for drinking water. Don’t damn our dam.

ENDS

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