The Murray-Darling Basin Plan will be hundreds of gigalitres short of its water recovery target when the nation hits a crunch-time deadline in 12 months and it will be farmers who bear the consequences of years of government inaction.
The southern basin state governments will be forced to reduce water allocations, possibly as soon as mid-2024, to compensate for the shortfall, which is expected to range from 190GL to 315GL.
The specifics will depend on what happens during the next 12 months, but the MDBP legislation gives a general outline of the dire course of events set to unfold.
Taking a step back in time, in 2017 the basin governments agreed to 37 water saving measures - either infrastructure or rule changes - that would allow an additional 605GL to stay in the consumptive pool.
The state governments had seven years to complete the projects and lock in the increased amount of commercial water and avoid the upcoming consequences.
However, the plan is drastically off course with only nine projects operational. The Murray-Darling Basin Authority has already ruled a further six projects won't be completed by the mid-2024 deadline.
More than a dozen could be completed in time if all the planets aligned, but according to a recent report the "delivery timeframe is challenging" for several projects.
The MDBA has conceded in the best case scenario, the states will recover 415GL and in the worst case just 290GL, leaving the plan between 190GL and 315GL short of the promised 605GL target.
Currently, state governments have until the end of the year to put forward any changes to their water saving projects. Then, from the start of 2024, the MDBA will begin calculating the final shortfall over the next six months.
The authority is expected to provide the Water Minister the final shortfall before June 30, along with recommendations about how to adjust each water region - or Sustainable Diversion Limit (SDL) - to compensate for the gap.
There is no requirement for the Commonwealth to make up for the shortfall, but it is expected to adjust the plan accordingly. If the Commonwealth accepts the MDBA recommendations, it will move legislation to alter the plan.
If the motion successfully moves through parliament, then the southern state governments would have less water to grant and be forced to reduce allocation to comply with the new SDLs.
None of this applies to the 450GL of environmental water, which the Albanese government has promised to deliver in full. There is no deadline, nor legislative consequence, attached to the 450GL recovery.
There is a limit to how much water the government can purchase in pursuit of the goal, with 225GL remaining under the cap.
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