Dozens of stakeholders have shared their perspectives over the two-day Listening to the Lachlan conference, organised out of concerns about the project's environmental impacts.

They have now issued calls to communities and governments to fully examine the cost-benefit analyses of raising the wall, to examine alternatives that might increase water security, and to invest in the protection of the Lachlan River system.

It's now approaching three years since NSW and Australian governments made the joint announcement that the wall would be raised 10m - from 85 to 95m - giving the catchment an additional 650 gigalitres of capacity. At the time the region was in the third year of drought.

By the end of 2021, the call to "raise the wall" was a call to increase the Lachlan valley's flood mitigation capacity.

In between, the potential costs of the project have made headlines, and Infrastructure NSW has highlighted the challenges of delivering such large-scale projects in the current conditions.

Listening to the Lachlan heard from some 18 speakers about the impacts - from personal to big picture - the project could have - and highlighted how much remains unknown.

Kerri Webster will lose part of her family property to compulsory acquisition, Louise Crawford will lose land and access.

In their words, raising the wall is "robbing Peter to pay Paul".

"How can you put a price on what we and other farmers will lose possibly for the gain of other communities?" Kerri said.

She also shared experiences of previous flooding and said a 2010-type flood event on top of the development would be "terrifying".

Gordon Turner and Hugh McLean from the other end of the Lachlan spoke of the value of the water that makes it to the end of the system, both in economic terms to agriculture and environmental terms.

Mr Turner is the last irrigator on the river, and spoke about the complexity of the wetlands, including the Great Cumbung Swamp.

"We're using taxpayer funding to remove an asset from one section of the community - without compensation - (and give it) to another," he said.

Based in Forbes in the mid-Lachlan, Lachlan Valley Water's Mary Ewing highlighted the variability of inflows into Wyangala, the past six years proving how quickly the region can go from flood to drought and back to flood.

While acknowledging the need for further analysis of the impacts of raising the wall - and for that analysis to be shared with stakeholders - she highlighted that the Lachlan River system is a regulated river system.

It's now more than 50 years since the current Wyangala dam was expanded, but the region has continued to grow in population and industry.

Lachlan Valley Water has been one of the local voices calling for work towards the raising of the wall to go ahead.

They were just a few of the voices of river communities, academics and those invested in water management also addressed the conference.

Professor Richard Kingsford from the University of NSW was one of the organising committee, along with Cowra's Pennie Scott.

"Everybody (at the conference) learned a lot and has a better appreciation of the current information base, concern about the lack of transparency in the decision making and the need to really measure the costs of building a bigger dam," Richard said.

"The resolutions are focussing on what we know - using as much information, being as transparent and rigorous in the cost-benefit analyses, that showed quite clearly what the costs are going to be.

"And they're not just costs of where the dam is, they're the downstream costs too, the floodplain graziers, the First Nations people and the environment."

There was a lot of discussion, he added, on the alternatives to raising the wall.

The resolutions in full are a call to governments and communities to:

Cowra's Pennie Scott said it was satisfying and fulfilling to have finally sat down in one room with so many people who have an interest in the Wyangala wall raising, two years on from starting to try to organise the conference.