Murray-Darling Basin Plan poised to fall short by 2024 deadline

The Murray-Darling Basin Authority assessed the progress of the state governments' water saving developments - known as SDLAM projects - and found they would only deliver between between 290 and 415 of the 605GL required by mid-2024, chief executive Andrew McConville revealed.

"Put another way, we expect a shortfall of between 190 and 315 gigalitres," Mr McConville said in an address to the National Rural Press Club.

"This means the Authority will have no choice but to recommend to the Federal Water Minister amended sustainable diversion limits in southern basin catchments."

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The shortfall could be much higher, as the estimation does not include the 450GL of environmental water, of which only 4GL has been recovered. To put the figure in perspective, Sydney Harbour is roughly 500GL.

The MDBA is so certain the water recovery targets will not be met in time, it will start working on options to make up the shortfall for the government to consider in December 2023, six months before the water recovery deadline.

"Of course, the actual steps to bridge any expanded water recovery gap will be a decision for Basin governments," Mr McConville said.

"The decision in terms of whether an adjustment will be made and to water extent does rest with the [federal Water] Minister."

By law, the federal government is obligated to recover any remaining water, which would most likely involve voluntary water licence buybacks.

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It's understood the federal and state governments will consider whether extending the 2024 deadline is a viable option in February.

However, it may no longer be a solution, as the report found several projects would need "another five to 10 years beyond 2024 to be finished", while Menindee Lakes project will deliver significantly less water than anticipated after being reduced in size by the NSW government.

"These SDLAM projects are like a credit to water users... the 605 Gigalitres credit has been banked and payment in the form of operational SDLAM projects must be delivered by 30 June 2024," Mr McConville said.

The federal government recently revealed it was investigating 46GL-worth of "strategic buybacks" with the state governments.