Mr Pearce said the alternative proposal would see council contract to take 4 million cubic metres.
"It would include 30 million cubic metres of water provided free for the first six years," he said.
Mr Pearce said this proposal would provide council with at least as much environmental benefit as the original 2014 plan, with increased economic benefit through its return from its investment in the dam.
Central Hawke's Bay farmer Fiona Hartly, whose family has farmed Pourerere Station for two generations, disagreed with Mr Pearce, voicing her support for Option C.
She said on-farm water storage, with farmers taking both investment responsibility and risk, was the norm "out at the coast" and that council did not have a mandate to transfer this risk over to ratepayers for the benefit of 150 farmers.
"The proposed $80 million would be better spent subsidising on-farm water storage for farmers in need throughout Hawke's Bay."
Environmentalist Dan Elderkamp also chose Option C, saying the regional council has not presented any scientific details, facts or proof that additional water for the environmental flows is needed, should the dam be built.
"The amount of $36.9 million could be far better allocated to environmental projects across the whole region, not just the Tukituki catchment, considering that all the region's ratepayers would be contributing to this proposal," he said.
Fellow environmentalist John Cheyne took the opposing view, saying that if the council were to purchase an extra 4 million cubic metres per year for environmental flows, a number of environmental projects could benefit from this additional water.
In response to the submissions, council officers noted a number of submitters questioned the impact of the purchase of environmental flows on ratepayers, stating: "Environmental flows should not be paid for by the ratepayers, especially considering that this option would not be required if there were no dam in the first place!"
The officers said it was important to realise that the proposal to purchase environmental flows would not be funded from rates.
"But will be funded from [council's] regional income budget which receives dividends from both Napier Port and the [dam] should it proceed, these funds are applied to, amongst other things, environmental projects," the report reads.
Council's chief executive, Liz Lambert, said she does not know if council would be purchasing the additional water or not, as they will be deliberating this tomorrow.
"Any amendment to the Long Term Plan, once decided by council, will be finally considered and is expected to be adopted at council's meeting on June 29," she said.
Councillor Peter Beaven said the submissions are strongly against the council not having to buy its own water.
"You can't ignore such overwhelming views, it is a brave council that would do so," he said.
"I think if we want to go ahead and take water - we have to find a way with HBRIC to factor it into the cost of the dam somehow or the returns that the council gets."
