The Hawke's Bay Regional Council's investment company says it will know by the end of the year whether construction of the Ruataniwha Dam will go ahead.
No appeals have been lodged with the High Court on the Tukituki Catchment Proposal Board of Inquiry's decision to grant consents for the water storage scheme, which include strict conditions on nitrogen leaching from farms.
Hawke's Bay Regional Investment Company chair Andy Pearce said construction of the dam now depends on farmers agreeing to buy 45 million cubic metres of water each year.
"Currently, we have about 20 million cubic metres that are completely contracted, so signed by both parties. We have another 15 million cubic metres in round numbers that are well progressed. A sizeable fraction of those are only awaiting counter-signatures, so that's 35 million. We have at least another 20 million working their way towards conclusion."
Dr Pearce said talks with one investor were well progressed and two more were now likely to commit.
"Those other two were waiting to be in a position where the consents were no longer challengeable. Now that we're clear with the consents, we'll be looking to see whether there are additional parties who may now be investing," he said.
"We're confident we're in good shape on the investment front."
When asked how long the company was giving itself to secure the remaining investors and water sales it needs to commence construction, Dr Pearce indicated the deadline would be the end of 2015.
"We've said fairly consistently for a while now - a period of four months from having the consents no longer subject to challenge. That would put us somewhere near the end of this year, the end of November or early December," he said.
"I'm not saying it's going to be easy. There's a lot of work to be done over the next four months, but there's no reason to believe we won't get there."
Dr Pearce said the scheme had the potential to irrigate 30,000 hectares of farm land.
'More certainty' around dam environment rules
Federated Farmers Hawke's Bay president Will Foley said farmers had a lot more certainty now around the environment rules to investigate whether it would be worth signing up.
"One road-block to farmers signing up to the dam was they never quite knew what they had to contend with until this decision was finalised."
Mr Foley said it was pleasantly surprising there were no appeals to the environmental consents, given how controversial the project has been.
Meanwhile, South Canterbury's Opuha Dam water level remains below average for this time of year, despite recent rainfall and snow.
Farmers who irrigate from the dam spent a majority of the past summer on restrictions because of rapidly decreasing water levels, and in February, the dam's taps were turned off for the first time in its 17 years of operation.
Opuha Dam chief executive Tony McCormick said, while the water level wasn't where it should be yet, he's confident it will be full by the end of spring.
"Despite a slow start from our very empty position in March, where we were completely empty ... we've had a couple of good weather systems that have pushed us on now and we've just gone over 55 percent.
"We're still below average for this year, but looking very close to getting back into a position that would give us a reasonable amount of confidence that we should see a full lake by the end of spring."