The battle lines have been draw at the first meeting of the Hawke's Bay Regional Council, with Ruataniwha dam advocate Fenton Wilson being elected as chair over critic Rick Barker.
About 150 people showed up for the packed meeting, with many from Central Hawke's Bay arriving in a show of support for the $600 million Ruataniwha water storage project.
With four advocates for the dam on the council and four critics, the king-maker was new councillor Dave Pipe, who provided the fifth crucial vote to get Mr Wilson over the line ahead of Mr Barker.
Mr Barker is part of a bloc of four councillors who have criticised the lack of information on the dam. He urged the new council not to make the mistakes of the Clyde Dam project and let emotion rule the decision making.
Mr Barker said none of the newly-elected councillors oppose the dam, but the debate must be based on logic and reason and for it to go ahead it must be financially and environmentally viable.
"As far as I'm concerned this is about logic, about reason and about judgement. And there's two main criteria for me: it's got to stack up financially and it's got to stack up environmentally and the cases on both sides have to be compelling."
Councillor Rex Graham, who is part of a bloc of councillors who have criticised the lack of information on the dam, was mocked by the crowd when he pointed out his group had not said they oppose the project.
The council will decide next year whether the controversial project will go ahead.