The council is proposing Plan Change 6 be based on a "single nutrient management approach" where water quality limits and targets are based on measuring phosphorus levels.
Opponents of the scheme, including the Fish and Game and the Environmental Defence Society, have argued the regional council needs to take a "dual nutrient" approach, controlling levels of nitrogen in the water as well as phosphorus. The board asked planners to flesh out areas of difference under both approaches.
A 118-page document filed with the board on Friday reveals that after two days of meetings between planners last week, fundamental disagreements between the parties still remain as to the best approach for Plan Change 6, although agreement has been reached on some elements of the plan.
Other changes have been made to the plan during the course of the hearings, as a result of earlier discussions between the council and submitters.
HBRIC plans to invest up to $80 million in the Ruataniwha water storage scheme if the business plan for the project is approved by the regional council once the board of inquiry delivers its decision on consenting issues.
The board has so far heard five weeks of evidence and has split its sitting time between Hastings and Waipawa. When the hearing resumes on Wednesday it will sit for two days at Matahiwi Marae, near Clive, where Ngati Kahungunu Iwi Incorporated will present its case against the project.
The inquiry will then return to Waipawa for the final few days of hearings and it is expected to conclude next week.
The board is due to release a draft decision, outlining conditions under which the scheme could proceed, next month or in March.
The draft decision would be open to submissions, with a final determination on the scheme required by April.
