Te Waikoropupu Springs' water conservation order hearing wraps up

Thursday, 28 June 2018

Te Waikoropupu Springs, near Takaka, have some of the clearest waters in the world.

The future protection of one of the world's clearest springs is as murky as ever.

The Water Conservation Order hearing for Te Waikoropupū Springs in Golden Bay has been running in Takaka since April and its public phase finally concluded on Thursday.

It was adjourned so legal counsel could answer questions from the special tribunal.

This week wrapped up a long process in which the co-applicants for the order, iwi Ngāti Tama ki Te Waipounamu Trust and Andrew Yuill, and dozens of submitters were heard.

On Wednesday the tribunal heard evidence from Dr John Gamlen, a retired mathematician based in Golden Bay.

*** Te Waikoropupū Springs hearing adjourned over challenge to evidence

Retired Golden Bay mathematician Dr John Gamlen.

* Te Waikoropupū Springs Water Conservation order begins in Takaka**

In May, a last-minute submission was tabled on behalf of Gamlen, criticising the expert evidence of Tasman District Council (TDC) scientist Andrew Fenemor.

The surprising new evidence threw a spanner in the works, forcing the tribunal to adjourn until this week.

Fenemor had earlier presented evidence on how nitrate levels would affect the Springs if further irrigation was allowed, using the nutrient-budgetting modelling software Overseer for his predictions. He concluded it would not harm the Springs if irrigation was doubled in the catchment.

But Gamlen said there wasn't sufficient data available to make accurate predictions that might be useful in determining nutrient limits at the Springs.

Tasman District Council expert witness Andrew Fenemor.

Gamlen was concerned the inaccuracy of Fenemor's predictions may be much greater than 30 per cent, rendering the predictions meaningless.

'It doesn't matter how much modelling you do, the fact is, garbage in, garbage out, so to speak. If modelling uses inaccurate input data, then the outputs are likely to be inaccurate.'

Gamlen said Fenemor's modelling assumptions 'didn't fit properties of the Arthur Marble Aquifer (AMA).

No mathematicians, he said, had ever had the chance to find out how Overseer worked, therefore couldn't peer review it.

'The scientific community only accepts science which is completely transparent, so that any scientist could repeat calculations. Peer review only by friends an associates on is not sufficient.'

In his rebuttal, Fenemor said Overseer was an 'empirically tested model' based on and validated with measured data.

He said he had not previously heard that senior mathematicians and modellers do not accept the scientific validity of the model and found it 'odd' that Gamlen would nevertheless consider it useful for farmers.

Fenemor called the Overseer modelling 'better than guesswork'.

'The nitrate modelling is fit for the purpose for which it has been used, i.e. to examine the sensitivity of Te Waikoropupū nitrate outputs to changes in land use in the recharge area.'

The modelled projections were only one tool to inform limits and the management of water quality within limits.

Fenemor said he acknowledged the difficulties of even attempting to model the flow and nitrogen fluxes in the Springs' system. However, the modelling he had reported had been carried out with the input of an interdisciplinary group with geology, hydrology, geochemistry and mathematical modelling expertise.

'I consider the results are conservative, and can be relied upon for the purposes and subject to the assumptions and uncertainties that I have described in my primary and supplementary evidence.'

On Thursday, the tribunal heard closing statements both from the co-applicants and TDC's legal counsel.

TDC lawyer Chris Thompson said it supported the granting of the order, but it should not include the Arthur Marble Aquifer because it was 'not outstanding in its own right.'

Thompson said the aquifer should instead be treated as a 'contributor' to the outstanding characteristics at the Springs.

The order needed to be 'workable for council' as the consent authority for administering it.

Legal counsel for the applicants, Rosie Hill, said the tribunal had heard significant and uncontested evidence as to the natural state of Te Waikoropupū and the aquifer, the outstanding values of those waters, and the value of contributing waters.

The restrictions, prohibitions, and limitations in the order were evidence-based, rather than purely precautionary, she said.

'I reiterate that this order is not intended to, nor can it legally, affect existing resource users. Those operations are protected.'

'I emphasise again the pride shared among the community, including primary and secondary industry, as to the current outstanding water quality and associated values. These are what the order will seek to protect for future generations. '

She said there was no compelling case for additional abstraction, or to increase water quality limits beyond those offered in the order.

'The primacy of preservation afforded by the legislature to the uncontested and outstanding values of Te Waikoropupū and the aquifer cannot be defeated simply by striving to achieve a balance of other users, with undefined aspirations.'