The ecology in the area where the proposed Mahinerangi wind farm will be built is not unique, and will suffer little damage during construction of the $400 million project.
Ecologists gave evidence on behalf of applicant TrustPower yesterday, as the company continues to outline its proposal.
Freshwater ecologist, Ian Boothroyd, said as a result of trying to avoid environmental effects the envelope for the development had shrunk.
It covered 1723ha, down from more than 5000ha when the project was first considered.
Areas which have been avoided because of environmental concerns included Black Rock scientific reserve, Deep Stream catchment, major rocky tors and Te Papanui conservation reserve.
Further studies had led to the exclusion of moderate and high quality water gullies, streams and waterways and large rock slabs.
Vegetation in the area was mirrored in many other areas in Otago.
Streams within the envelope had no unique communities with only two fish rated as nationally threatened: Eldon’s galaxiid and longfin eel.
Movements of fish would not be affected, as culvert design and maintenance can avoid any impacts on fish passage.
Up to 1.18m cu m of surplus fill would be generated by earth works during construction. Much of that would be dumped in the headwaters of lowvalue gullies.
Highvalue and moderatevalue gullies, which make up more than 92% of the gullies in the develop ment envelope, would be protected.
All lowquality gullies would be surveyed before fill, and if some significant vegetation was found, no fill would be placed in the gully.
Botanist Ruth Bartlett said by down scaling the project to a 1723ha envelope, a large area of highquality snow tussock grass land would be excluded.
Out of a proposed 100 turbines 83 would be on exotic grassland Construction of tracks would dis turb 96.6ha.
Only three gullies would be crossed by access tracks.
The area is suitable for four species of common gecko although only one, the Otago large gecko, is considered a threatened species.
TrustPower aimed to avoid geckos by having a 50m buffer zone around rocky habitat where the creatures lived. Predator con trol would also be introduced.
Geckos and skinks would be searched for immediately before construction started.
An area of snow tussock grass land of 68ha would be retired from grazing and placed under covenant for protection. Dr Bart lett said this was a significant positive mitigation gesture.
University of Auckland environ mental management professor John Craig, said bird death as a result of collision with towers or rotor blades varied greatly around the world.
Bird strike was considered unlikely at the Mahinerangi site he said.
As towers were not in a row, and large numbers of birds did not roam the area, and turbines were spread out, bird strike would be rare, he said.
TrustPower would introduce a pest control programme immediately prior to the bird breeding season.
By Steve Hepburn
Otago Daily Times
15 May 2007
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