The mayor of Tasman District says the defeated Waimea Dam could go to another vote.
The council this week narrowly agreed to quit the $100 million project, out of concern over ballooning costs.
New figures announced recently revealed it was likely to cost $26 million more than estimated in 2015, which put it at $102 million dollars.
Funding was to have been split between ratepayers and irrigators, helped by a loan from Crown Irrigation.
An opponent said it failed in part because of flawed risk management of the funding model
Golden Bay based businessman Roland Toder, said while he trusted the intentions among parties to pay back the loan, the risk to ratepayers was too great, especially in light of the regular cost increases.
"The risk is lopsided because the loan from Crown Irrigation had to be underwritten by the TDC (council) - that means the ratepayers were liable for that loan."
Dr Toder said council staff were confident it could be done, based on their data, which he questioned at the end of last year.
"There are a range of studies on large dams around the world, which concluded they weren't economic because of cost over runs of about 96 per cent."
Mayor Richard Kempthorne said the Waimea Dam was classified as a small to mid-size dam and the risk had been well scrutinised.
He said as it stood right now the project was dead, but a proposal may yet come forward that got the dam back for another vote.
"It may and I would certainly be willing to explore that.
"There's now a huge amount of work to do, and just some of the discussions yesterday within council is that the ramifications of it (the decision) are very significant, and it affects a lot of the workstreams of council."
Mr Kempthorne said the council was working under urgency on a way forward, that included how best to address increasing water shortages for urban users.
He said figures showed alternatives for the urban supply were likely to be more expensive than the dam, which has been a key project for the council for more than 15 years, triggered by a severe drought in the summer of 2000-2001 when the Waimea River ran dry.
Julian Raine, who grows apples, kiwifruit and boysenberries on the plains and was also president of Horticulture New Zealand, told Nine to Noon today that there was a broad agreement among multiple parties in the early years
But it came unstuck on the funding model.
Mr Raine believed Tuesday's vote by the council was swayed by a "noisy and vocal minority", and remained by far the best option from a cost perspective.
He said there was an equal need among rural and urban users, and the best way to make it happen was to combine resources.
Dr Toder believed alternatives lay in the possibility of amalgamation with Nelson City, which would mean Tasman might draw on Nelson's secure water supply.
Tasman District Council acting chief executive Richard Kirby told the meeting this week that the supply in Nelson was limited to only a small area of Tasman, and that water restrictions were imposed on Nelson city last summer.
Former Nelson Mayor Aldo Miccio led an attempt in 2012 to amalgamate the two councils. It was supported by Nelson voters, but Tasman voted against the idea, and it was lost.