The dam projects have split opinion within communities and politics alike.

Although many irrigators argue the dams are necessary to improve water security in dry times, an Upper House inquiry found the cost-effectiveness or benefits of some of the projects were yet to the proven. Much of the cost-benefit analysis will be part of the business cases, due at the end of 2021.

However, when The Land questioned the Department of Planning, Industry and Environment on whether the business cases would be made public a spokesperson stated it was "not standard government practice to release business cases for complex infrastructure projects publicly".

The reason given was that they contain detailed market and Cabinet-sensitive information that is subject to strict confidentiality requirements. The spokesperson said where relevant, some aspects of a business case could and would be included in the Environmental Impact Statement (EIS), which will be placed on public exhibition for at least 28 days as required by the DPIE.

"The Environmental Impact Statements contain detailed information about the benefits and impacts of proposed projects," the spokesperson said.

Lachlan Valley Water chairman Tom Green, Forbes, supports the raising of the Wyangala Dam wall, but said their expectation was that the business case would be made public.

"We'd like to see it released to know what potential costs there would be, part of which could be borne by water users," Mr Green said.

"We would also like to see the benefits of both flood management and water security and what they would look like.

"There's always some sensitivities and I can understand why there could be parts redacted but I would still expect the relevant information to be available."

Mole River Protection Alliance member Kate Boyd has concerns about the proposed building of Mole River Dam and said the community had been frustrated by limited answers to their questions on the project.

"Many of the answers have been 'we're working that out in the final business case', but we haven't even heard what water management options or alternatives are being worked through or costed," Ms Boyd said.

Ms Boyd noted summaries of business cases had been released for other infrastructure projects, after the decision had been made to proceed, but they didn't explain the details or all the assumptions involved.

"If $24 million of public funds are being spent preparing the Mole River Dam business case, we ought to see a great deal more than a 4000 word summary costing $6000 per word.

"Governments can make better decisions about public funding and resources if the community can provide well informed input during the development of a project."

But, not everyone agrees. Peel Valley irrigator Ian Coxhead said he would not like to see the business case for rebuilding Dungowan Dam made public in its entirety.

"It's like putting all your cards on the table at once," Mr Coxhead said.

"I think there's a lot of anti-dam people, with no skin in the game, who might misconstrue the business case, while having very limited knowledge of the benefits a new Dungowan dam would deliver."