A High Court decision may determine whether Waitaki hydro-electric power stations can be guaranteed water after 2025.
Genesis Energy and Meridian Energy both want to ensure the resource consents they hold for the eight power stations they own will be renewed when the consents expire in 2025.
A panel of three commissioners, appointed by Environment Canterbury (ECan) and chaired by Environment Court retired Judge Gordon Whiting, is considering making changes to a 2006 Waitaki water plan which will ensure that happens.
Under the Waitaki catchment water allocation regional plan, the resource consents are a discretionary activity, which means they could be declined in 2025.
In changes being considered by the panel, the two companies want that status changed to a controlled activity, which meant they could not be declined although conditions could be applied.
However, the issue has been raised if that is legal under the Resource Management Act.
To complicate that, the High Court is hearing an appeal against ECan's Land and Water Regional Plan on that very issue.
That plan allowed for controlled activity status for infrastructure of regional significance but, again, the legality of that was questioned.
Because the High Court decision could directly effect the panel's decision on the power stations' Waitaki resource consents, Judge Whiting has now decided any decision would wait for the ruling.
''The decision of the High Court regarding the availability of controlled activity status will be binding on us, and we should not predetermine that outcome,'' he said in a minute issued this week.
During the panel's hearings in Oamaru last month, it became apparent the court's decision could relate to the merit of which status should be applied to the hydro resource consents in the Waitaki plan.
''We accordingly propose to wait until the decision of the High Court is available before determining the matter,'' Judge Whiting said.
After the decision was delivered, the panel would then decide how the status of the consents would be addressed, including whether further submissions were needed for those who had made submissions on changes to the Waitaki plan.
In the meantime, it would still consider other changes to the plan, including the minimum flows in the lower Waitaki River and allocating more water for irrigation between the Waitaki dam and Black Point.
That included recommencing the hearing in Oamaru on August 10 for ECan's right of reply.
In evidence presented to the panel by Genesis and Meridian last month, they acknowledged the chance of new consents not being issued for hydro generation was very slim, but said the possibility existed.
If new consents were not granted, generation would have to stop, reducing New Zealand's electricity supply by 19%.
