The Conservation Department is to appeal against water consents granted to 17 avocado growers north of Kaitaia.

Photo: RNZ/Carol Stiles

Independent commissioners acting for the Northland Regional Council gave the growers consent this month to draw more than 2,000,000 cubic metres a year, from the Aupouri aquifer.

DOC objected strongly at the time, saying the council did not have sufficient hydrological research on the aquifer and its relation to nationally significant wetlands to support the decision.

Statutory manager Hamish Eglinton said that was the basis of the appeal to the Environment Court.

Mr Eglinton said the effect of the massive groundwater on the Kaimaumau wetland, which is of national importance, was uncertain.

"We just don't know enough about potential effects. There doesn't seem to be a lot of scientific advice, or background data on what effects this will have," Mr Eglinton said.

The avocado growers, some of them big investors, were expecting DOC to appeal.

Many local residents were less certain, but some who had been worried the avocados would suck up all the water and leave nothing for them were pleased to hear the matter would go to court.

Deer farmer George Stanisich was not overly hopeful of DOC's chances, but said there was a lot at stake for all residents of the Aupouri peninsula who relied on bore water.

"No-one knows how much [water] is under there to start off with," he said.

"They're only guessing. And what happens then ... they take the fresh water out, the salt water comes in, and bang, you're buggered: the whole aquifer underneath is contaminated with salt water."

The council believes it can avoid that disaster by monitoring the bores and adjusting the take as it goes.

In its appeal application, DOC said the council had failed to have proper regard for the cumulative effects on the aquifer.

Meanwhile, Forest and Bird is challenging another proposed development in the Kaimaumau wetland.

In April, the regional council gave Auckland company Resin and Wax consent to mine peat on Ngai Takoto land, and extract valuable industrial compounds from the soil.

Forest and Bird's in-house lawyer Sally Gepp said she had been instructed to file for a judicial review of that consent, pending some last-minute talks with the developers.

"They have asked for a bit more time to go away and look at that. It basically relates to which parts of the site are particularly important and we'll consider that," she said.

Forest and Bird did not launch into legal proceedings lightly and would make a final decision next week on taking the council to judicial review.

The society appreciated Ngai Takoto's wish to develop land it bought back with its Treaty settlement, Ms Gepp said.

But peat-mining could damage the ecology of the Kaimaumau wetland and it was important that Northland develop in a sustainable way, she said.

"That includes iwi being able to use land. But in this case the land that has been bought is ... the second-most important wetland in the region, and our concern is the way the Northland Regional Council has dealt with this," Ms Gepp said.

A council spokesperson said it had been dealing with numerous OIA requests from Forest and Bird and DOC about the peat-mining consent.

DOC said it was still considering whether it too should challenge the consent in the High Court.