Unity may be a bridge too far

Fish & Game accepts that there may be room to move in designing a hydroelectric scheme for the Wairau River which would satisfy concerns about effects on fish, game birds and angling.

The difficulty would be identifying flows which would sustain habitats in and below the affected reach, Fish & Game Nelson Marlborough manager Neil Deans yesterday told an Environment Court hearing in Blenheim considering whether TrustPower should be granted resource consent for the scheme. Fish & Game has appealed a Marlborough District Council-appointed panel's earlier decision to grant the consent.

Evidence to the court was not sufficiently credible to provide confidence in recommended flow regimes, said Mr Deans.

Ideally, all parties with an interest in the application would work towards agreeing on potential adverse effects and threshold trigger levels, said Mr Deans. However, he was unsure whether the parties could reach consensus and of the time this would take.

Reducing the distance between TrustPower and Fish & Game would be difficult when there were so many uncertainties about the biological consequence of altered flows, he said. Other contested issues included impacts on water temperature and clarity.

There was also disagreement on objectives, said Mr Deans. For example, TrustPower expert witness Greg Ryder argued that habitat loss of 30 per cent as a result of a changed flow regime would be acceptable. Studies on other catchments had suggested about 10 per cent would be more appropriate.

The aquatic management plan prepared by TrustPower did not contain the detail needed for intentions to drop out in conditions, he said. For example, a single bullet point flagging potential effects on fish communities was inadequate. Anglers' interests should be looked after by specifically protecting the productivity of salmon fisheries.

Another difficulty Mr Deans had with the management plan was: "What happens if things in it aren't adhered to? Does that mean the consent holder is in breach? My understanding is that they would not be."

It had already proved impossible for the Marlborough District Council to operate two flow regimes on the Wairau River, said Mr Deans. During the 2005-06 summer, on at least 16 occasions the flow at Tuamarina dropped below an eight cumec trigger level, reaching close to six cumecs at times. This should have required all class B irrigation takes upstream to be immediately stopped.

"But council didn't give effect to plan requirements because low flows were redefined on a daily average rather than instantaneous basis."

Mr Deans was critical of the "adaptive management" regime proposed by TrustPower. The concept might work for a marine farm which could start with 10 hectares then expand in increments if there were no adverse effects, he said. But the effects of the TrustPower scheme would not be reversible.

"Considerable debate about environmental effects versus economic viability" was likely, said Mr Deans. While TrustPower argued that it would carry the risk of being required to alter flows if there were environmental repercussions, the river's natural values were also at risk.

Proving that any changes in the river's biology were caused by the scheme's operation would be difficult with so many natural variables, such as climate playing a part, he said.

"The extraordinary thing about the Wairau is that it is a long river but it has high angling pressure," said Mr Deans. "The chances are that you will find a reasonable stretch of water no-one else is on and get not only a fish, but a potentially large fish."

National water conservation orders had been applied to the Mohaka, Buller and Rangitikei rivers due to outstanding trout fishery values.

Mr Deans' credibility as an expert witness was attacked by TrustPower lawyer Christian Whata, who suggested that as an advocate for Fish & Game he lacked the independence required.

Mr Deans acknowledged the potential conflict of interest in his role as an expert witness to the hearing and a Fish & Game manager. However, as his expert views and those of the Fish & Game council were aligned this was not the case, he said.

- The Marlborough Express

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