The company has plans for a small hydro scheme on the river and while it has not yet applied for resource consent, it wants to keep that possibility alive.
The Environment Court is sitting in Queenstown to consider whether a water conservation order should be amended to prohibit any damming or diversion of the river. The case has spanned six days so far and the final evidence will be heard today.
It was being heard at the same time as an appeal against plan change 5 in the Central Otago district plan, which related to the landscape values of the Nevis valley. Some of the valley was classified as an outstanding natural landscape under the plan changes and the rest was deemed to be of less value and listed as a "significant amenity landscape".
The New Zealand Historic Places Trust and Otago Fish and Game councils objected to the two different classifications and said the entire valley should be listed as an outstanding landscape. On Monday, the court was told the parties involved in that appeal, including the Central Otago District Council and Pioneer, had reached an agreement the whole valley should be an outstanding natural landscape (ONL).
Lawyer for the district council, Jayne Macdonald, said a memorandum would be drawn up and signed by all parties. Judge Jon Jackson said once that was done, the appeal would be allowed by consent.
Pioneer asset manager Peter Mulvihill issued a statement yesterday saying the classification did not prevent a "carefully designed hydro development".
"There are many examples in Central [Otago] of ONLs with dams and reservoirs, such as the Upper Manorburn, Lake Onslow and Butchers Dam, which are a significant feature and an important part of the landscape. We even have mining currently occurring on the existing ONL in the Nevis Valley," he said.
Pioneer was "comfortable" with the change to the boundary of the outstanding natural landscape classification in the Nevis Valley.
The company had already said in any future resource consent application it would limit the extent of any proposed dam so impounded water did not go beyond the Nevis Crossing bridge. Any lake would be about 14ha.
Pioneer owns the leasehold of two farm properties on the banks of the Nevis River - Ben Nevis and Craig Roy Stations. Both stations are Crown leases and are going through the tenure review process.
Mr Mulvihill said the memorandum was consistent with the tenure review covenants and Pioneer's commitment not to go above the Nevis Crossing with any dam reservoir.
A fortnight ago, during earlier evidence in the hearing, Mr Mulvihill said he was confident the dam was a viable prospect.
Asked if Pioneer was working with another generator on the project, he said it was not.