Tunnel 'too damaging' for Waitaki ecosystem

Diverting water for Meridian Energy's $900 million North Bank Tunnel hydro scheme risks environmental damage and its consents should be quashed, opponents say.

Meridian wants to build a 34 kilometre-long tunnel from the Waitaki Dam to the lower Waitaki River.

The state-owned power company was granted consents by independent commissioners last December, but the decision was appealed to the Environment Court.

Five appeals were lodged, but four have been withdrawn.

At a hearing in Christchurch yesterday, Lower Waitaki River Management Society lawyer Camilla Owen told Judge Jon Jackson and three commissioners that the effects of the scheme were too significant and would not be sufficiently mitigated.

Likely effects included reduced water quality, reduced flows, a less braided river pattern, loss of wetlands and more didymo, she said.

"The society is saying that for the Waitaki, enough is enough, and although there may be a hydro-electric development on the lower Waitaki that might be acceptable ... the North Bank Tunnel concept is not it," Owen said.

Meridian said that although the tunnel would reduce the effectiveness of the Waitaki power station, enough extra power 1400 gigawatt hours a year would be generated to power the homes in a city the size of Christchurch.

The Waitaki is already New Zealand's hydro powerhouse, accounting for about 60 per cent of New Zealand's hydro storage.

Meridian lawyer Jo Appleyard has told the court that a managed variable flow regime would bring environmental benefits.

"New Zealand needs more electricity generation, and for the sake of the country and the planet, that generation needs to be from renewable sources."

While some of the negative effects of didymo may be "a little worse", flushing flows and channel maintenance could improve the situation, she said.

The society, which has fewer than 50 members, including some irrigating farmers, said the scheme was not in the national interest or economically efficient.

Owen said the society wanted a community-based management plan for the lower Waitaki.

Yesterday was the tenth day of the appeal, with most evidence to date heard in Oamaru.

The hearing is expected to end tomorrow, with a site visit by the judge and commissioners later in the week.

Meridian applied to Environment Canterbury in 2006 for consents to take water for the scheme, attracting 438 submissions, with more than 400 in opposition. Consents were granted by independent commissioners last December.

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