By the second week of December 2022, the gauges along the River Murray in South Australia were telling Riverland fruit growers and State Emergency Service (SES) crews something the state had not seen in more than sixty years. Three consecutive La Niña years had drenched the river's headwater catchments in New South Wales and Victoria, and the resulting flood pulse was now working its way, slow and enormous, down more than 2,500 kilometres of river toward the sea. In mid-December 2022 (approx.) the South Australian Government declared a State of Emergency covering the River Murray corridor, from the Riverland towns of Renmark, Berri and Loxton, through Waikerie and Morgan, to Mannum and Murray Bridge closer to Adelaide. Flows at the Victorian border peaked at somewhere around 190,000 megalitres a day (approx.) — the largest flood the river had carried since 1956 — and did not fully recede for weeks. Thousands of properties were assessed as at risk (approx.), levees were built and rebuilt overnight, and low-lying river towns were evacuated as the peak moved downstream into the new year. For a river system that had been declared close to dying during the Millennium Drought less than fifteen years earlier — when Lakes Alexandrina and Albert at its mouth came within reach of turning to acid sulfate soil — the 2022–23 flood was a genuine relief and a reminder of how little control the state at the bottom of the system has over the water arriving at its door. South Australia did not create the rain that fell in Queensland's and New South Wales's catchments, and it cannot make more of it fall before the next drought; all it can do is manage what reaches it, and fight for its share of what does not.
What the government did
The Malinauskas Government, elected in March 2022, inherited both ends of this story: a river system still governed by the Murray-Darling Basin Plan — the Commonwealth law, made in 2012, that set a legislated Sustainable Diversion Limit cutting basin-wide water extraction by 2,750 gigalitres a year on average, with a further 450 gigalitres of "up-water" targeted through infrastructure efficiency measures under a 2018 bipartisan amendment (Murray-Darling Basin Authority, Basin Plan 2012) — and a flood emergency that arrived nine months into its first term. In office, the flood response ran through the SES, the Country Fire Service and local councils, backed by a joint state-Commonwealth River Murray Flood Recovery package of grants for flood-affected primary producers, small businesses and community infrastructure, worth several hundred million dollars combined across state and federal contributions (approx.; SA Budget Papers, 2022–23 and 2023–24). Much of that money went toward rebuilding the levees, irrigation pumps and river infrastructure the flood had damaged, and toward re-establishing Riverland horticultural plantings lost when floodwater sat on root systems for weeks.
On the Basin Plan itself, the government's posture has been consistent advocacy rather than new legislation — South Australia does not control the taps in New South Wales or Victoria, and its main lever is persuasion inside the intergovernmental Basin Officials Committee and the Murray-Darling Basin Ministerial Council. Premier Malinauskas and Deputy Premier Susan Close, who holds the climate, environment and water portfolio, have repeatedly and publicly pushed for the Commonwealth and the other basin states to deliver the full 450 gigalitre "up-water" target rather than wind it back, while ultimately backing the Commonwealth's Water Amendment (Restoring Our Rivers) Act 2023, which extended the Basin Plan's original delivery deadline to December 2027 (approx.) and reopened voluntary water buybacks after several years in which a legislated cap had effectively frozen them. Alongside that advocacy, the Department for Environment and Water (DEW) has continued funding environmental watering for the Coorong, Lower Lakes and Murray Mouth (CLLMM) icon site, and SA Water has kept the Adelaide Desalination Plant — built after the Millennium Drought as insurance against exactly this kind of upstream dependency — in a state of operational readiness rather than mothballing it once the flood eased the immediate pressure.
The strongest case
A shared river with five governments was never going to be fixed by one of them alone
The government's defence of its own record rests on a genuine structural fact: South Australia consumes a small share of the Murray-Darling system's water — its licensed entitlements are dwarfed by the irrigation industries of the NSW and Victorian Riverina and the northern basin's cotton and grain valleys — yet it carries a disproportionate share of the consequences when the system is over-allocated, because it is the last state the river reaches before the sea. Fixing that imbalance requires four other governments, three of them representing electorates with real farming livelihoods attached to every gigalitre recovered, to agree to reduce their own water use, on a timetable none of them fully controls either, given rainfall variability across a basin roughly the size of France and Germany combined. Given that reality, South Australia's choice to back a negotiated three-year extension rather than insist on an unmet 2024 deadline was arguably the more effective form of advocacy: a collapsed negotiation would likely have delivered less water, more slowly, than a Commonwealth-brokered deal that reopened buybacks and kept the 450 gigalitre target legally alive. And unlike much of its Basin Plan advocacy, the state's insurance policy is entirely within its own control — SA Water's desalination capacity and the CLLMM environmental watering program do not depend on any other government agreeing to anything, and both continued through a government that inherited them rather than built them from nothing.
The evidence
Adelaide's dependence on the river is the plainest number in this topic, and SA Water has published it for years without much political comfort attached: in a dry year, up to around 90 per cent of metropolitan Adelaide's drinking water can come from the River Murray, falling to roughly 40 per cent in a wet year when reservoirs fill from local rainfall instead (both approx.; SA Water, water security reporting). That range is the entire argument for the desalination plant in one statistic — a state capital of more than 1.3 million people (approx.) whose primary water source can, in a bad year, be almost entirely a river whose headwaters it does not control.
The 450 gigalitre efficiency measures target is the harder number, because it measures a promise rather than a river. Basin-wide, the Murray-Darling Basin Authority's own progress reporting put total water recovered toward the Basin Plan's 2,750 gigalitre core target at roughly 2,100 gigalitres by the mid-2020s (approx.; MDBA, Basin Plan progress reporting) — behind schedule, but visibly moving. The supplementary 450 gigalitres, the "up-water" specifically promised to South Australia and the environment as the price of the 2018 amendment that eased pressure on upstream irrigators, has fared far worse: MDBA reporting through the mid-2020s shows well under 50 gigalitres actually delivered (approx.), against a target originally due in 2024 and now pushed to December 2027. The SA Royal Commission into the Murray-Darling Basin, chaired by Bret Walker SC and reporting on 31 January 2019, had already found — years before that shortfall became undeniable — that the Basin Authority's method for setting the original Sustainable Diversion Limits gave weight to political and economic considerations that were never disclosed as clearly as the underlying science, and that climate change had not been adequately built into the modelling behind the numbers South Australia has spent a decade defending.
The critique
None of the interstate cooperation problem is South Australia's to solve unilaterally, but the gap between the government's rhetoric of "full delivery" and the 450 gigalitre reality is where the critique has to sit. A target that was already a compromise in 2018 — smaller, the Royal Commission found, than what the Basin Authority's own science suggested a genuinely healthy river system needed — has now been extended once, from 2024 to December 2027, and the volume actually delivered under it, in the tens of gigalitres against a 450 gigalitre promise, would need to accelerate dramatically inside roughly three years to meet even the diluted new deadline. The government's own public language of full delivery and no further watering down has not yet been matched by a published, credible schedule showing how the remaining several hundred gigalitres arrives on time; neither the Malinauskas Government nor the Commonwealth has released one.
South Australia's other structural problem is leverage. It is the smallest basin state by population and by irrigated water use, sitting at the end of a system where the states that would have to give up the most water also hold the most seats in a federation built on population-weighted politics. Every time a basin state government facing an irrigator backlash — and both New South Wales and Victoria have seen organised "no more buybacks" campaigns from irrigation communities in recent years — pushes for a slower or smaller recovery, South Australia's only real counter is public advocacy, not a vote it can win on its own. That asymmetry was visible in the 2023 extension negotiations themselves: the outcome removed the legislated cap on buybacks South Australia had wanted gone, but it also gave every upstream government three more years before its own recovery task has to be finished, and there is no enforceable penalty written into the legislation if December 2027 arrives with the 450 gigalitres still undelivered.
South Australia can build a desalination plant on its own authority. It cannot build the other four governments' water recovery on its own authority — it can only keep asking.
The state's exposure is not only about the headline gigalitre count. Upstream compliance failures — the 2017 revelations of unmetered floodplain harvesting and alleged water theft in the northern basin, and the metering and licensing reforms in New South Wales that followed — mean that even a fully delivered 450 gigalitres on paper would not guarantee that volume of extra water reliably reaches the South Australian border in a dry year, because the entitlements upstream of it were, for years, measured far less tightly than the target implied. Nor did the 2022–23 flood repair the underlying ecological stress: DEW's own monitoring of the Coorong — the Ramsar-listed wetland at the river's mouth — has continued to record signs of ecological stress in its southern lagoon even after the flood's flushing benefit, evidence that a single wet year, however large, is not a substitute for the sustained environmental flows the Basin Plan was designed to guarantee.
The risk to the future
The risk to the future
A state with no vote on the water it depends on most
The 2022–23 flood bought South Australia time, not security. Reservoirs are full, the Lower Lakes are fresh, and the Coorong has had its best flush in years — but the underlying arithmetic has not changed: a river system shared by five governments, a downstream state that consumes a small share of it but depends on it for up to 90 per cent of a capital city's drinking water in a dry year, and a 450 gigalitre environmental promise running at a small fraction of its target with roughly three years left on its once-extended deadline. If December 2027 arrives the way the original 2024 deadline did — with the gigalitres still mostly unrecovered and no legislated consequence for missing them — South Australia enters its next serious drought with less environmental buffer in the river than the Basin Plan promised, and with the same limited leverage it has always had over the four governments upstream. The Adelaide Desalination Plant is genuine insurance, but it is expensive insurance that covers drinking water, not the Coorong, the Lower Lakes, or the irrigators and river towns along the length of the Murray who have no desalination plant of their own. Every year the 450 gigalitres stays undelivered is a year South Australia's water security rests less on its own government's competence than on the willingness of governments it did not elect to keep a promise they are already years behind on.