"Any dam will be designed to store irrigation water and it is in summer that water will be drawn from it.
"So instead of being a nice, full lake for sports it will be a muddy banked, half-full pond which in the case of the Mangatarere would be lined with dead trees," Mr Woodcock said.
He said the society was especially outraged at comments made by Masterton District Council chief executive Pim Borren in a Times-Age column, that fuelled the "fallacy" of a sporting lake.
Mr Borren was simply a "council employee" who should remember he was responsible to the mayor and committee chairmen and should not be usurping their authority speaking out publicly on issues like the dam, he said.
"In any case he is hopelessly ill-informed," Mr Woodcock said.
The society had been trying to flush out dam promoters for a public debate but had been turned down.
"It seems most stakeholders have been told to keep quiet and only a handful of project organisers will say anything at all."
Farmers, he said, had to be aware of the cost to them of buying water.
"That's what the debate should be about, not building a place for rowing or fishing."
As far as water costs were concerned Mr Woodcock said it was suspected the cost would exceed 25 cents a cubic metre, in which case it would be uneconomic.
"At that price it would actually be cheaper for farmers to scrap the water project and buy in more supplementary feed."
Schemes elsewhere, including Ruataniwha and Waimea, were troubled and the price issue was the crux of any plan to proceed here, he said.
"If buying the water is not economic for dairying then they will not achieve the land use changes they are relying on.
"At present Wairarapa is 20 per cent dairy and they see it as rising to 45 per cent, at the expense of sheep and beef.
"For that to happen it would have to be economically viable, so they have to come out and tell farmers the true facts, instead of creating the myth of a boating and fishing utopia." Mr Woodcock said.
He said that between $2 million and $4 million had already been spent "mainly on consultants" and there had been a lot of talk about climate change and droughts meaning water will "become the new gold".
"What that appears to completely overlook is that it has got to rain first."
Mr Woodcock said Wairarapa Water Use Project has signalled it will be settling on one or two dam locations within the next three months, but farmers still had no idea what was involved even in matters like how the water would be reticulated.
"Will it be piped underground, travel through huge pipes overland or be sent to farmers in open channels, we just don't know.
"It's time to debate the facts, give us the facts not just try to get a rosy headline in the paper."