Wetlands alongside the Waitaki River have an uncertain future if Meridian Energy builds a new power scheme there, Dunedin ecologist Stephen Rate told the Environment Court yesterday.
Meridian has acknowledged taking water out of the river for its north bank tunnel concept power scheme between the Waitaki dam and Stonewall would reduce the area of wetlands, and proposes an adaptive plan to manage that.
The plan, in draft form, would be finalised after monitoring before the scheme was commissioned and provides for measures that could be changed if effects emerged after the scheme started generating.
Dr Rate said this adaptive management-plan approach had been used because there was a lack of information on wetlands and uncertainty about the effects and mitigation.
He was not impressed with the mitigation. He said the significance of wetlands had been underestimated and there was "a high degree of uncertainty" regarding potential effects and the practicality of mitigation options.
Dr Rate said the wetlands that could be affected were of considerable ecological importance.
Meridian had insufficient detailed information to adequately assess potential effects on birds, fish, invertebrates, wetland vegetation and threatened plants.
However, Meridian's witnesses, who have already presented evidence to the court, did not agree, and rejected some of Dr Rate's assertions.
Cross-examined by Meridian counsel Jo Appleyard, Dr Rate said he had spent a day looking at wetlands at the Waitaki River, some close-up and others from a distance.
He said he had not talked with Meridian's wetland specialist, Diana Robertson, to discuss the issues he had. That was not part of his brief, he said.
Ms Robertson had said the adaptive management-plan approach was used because it was the best way to manage complex and interconnected ecological effects of a large project.
There was sufficient information to assess effects and appropriate mitigation. If the scheme was built, further monitoring would ensure the best decisions were made, she said.
