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It might be the biggest whodunnit — or what-dunnit — in Australia.
More
than 2 trillion litres of water — enough to fill Sydney Harbour four
and a half times — has gone missing from our largest and most precious
river system — the Murray-Darling Basin.
And it’s happened in what was already
one of the driest periods the basin has seen.
According to an investigation by some of Australia’s top water scientists,
shared exclusively with the ABC, 20 per cent of the water expected to
flow down the rivers from 2012-2019 was simply not there. That’s despite
almost $7 billion being spent to protect the health of the system’s
rivers and ecosystems that rely on them.
Was it stolen? Was it lost? Has climate change made it go up in steam? Or was it simply never there in the first place?
There
are clues scattered up and down the rivers but one simple message is
clear in the scientists’ findings. For the first time, they provide
evidence that the Murray-Darling Basin Plan — the most expensive
environmental program in Australia’s history — is delivering much less
water than was expected.
And the implications could be huge.
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The Murray-Darling Basin covers a seventh of the continent, is home to nearly 10 per cent of Australia's people, and produces a third of our food.
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The Murray-Darling Basin is enormous network of rivers, creeks, wetlands and valleys.
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“It’s a huge discrepancy to be missing a fifth of the water that’s
meant to be in the rivers,” said Jamie Pittock from the ANU. He’s an
expert in water management and a co-author of the Wentworth Group’s
report.
“It means that there are all sorts of things that
Australians value that won’t be sustained … like more water for towns …
the floodplains, growing grass for sheep and cattle, in terms of
biodiversity being conserved, waterbirds, red gum forests and conserving
our fish.”
Rob Vertessy is a hydrologist and chair of the
Murray-Darling Basin Authority’s (MDBA) Advisory Committee on Social
Economic and Environmental Sciences.
He said the report was an important contribution to the body of scientific knowledge on the system.
“It
is pointing to a problem, which I guess people have had a sense of, but
which hasn’t been properly dimensioned until now,” Professor Vertessy
said.
“The levels of flow in the river are lower than everyone would have hoped.”
The
MDBA itself worked with the Wentworth Group to help with the analysis
over the past several months, and is completing its own similar analysis
set to be released later this year.
The MDBA’s head of basin
strategy, Vicki Woodburn, said the shortfall was not a failure of the
basin plan itself, since it was still being implemented.
The missing water is a mystery — nobody knows exactly why it’s not being seen in the rivers.
But
here’s the thing: there are clues. Lots of them. We’ve seen water go
missing up and down the river with clear explanations before. And
looking closely at the new report, many of those explanations are
consistent with the new data.
Clue one: tampered meters and criminal prosecutions
One possible explanation for the shortfall is that some of the missing water has been stolen.
An investigation by Four Corners in 2017 put water theft in the spotlight — much of it around the Barwon-Darling catchment in the Northern Basin.
Irrigators there,
according to official figures, use 3 per cent of all the water taken from the entire Murray-Darling Basin.
But
on top of those official figures, there has been significantly more
water taken in that area. The Murray-Darling Basin Authority
itself estimated that in the Northern Basin, as little as 25 per cent of surface water take has been metered.
Some of the water that went unmetered was stolen.
Peter Harris, who was named in the 2017 Four Corners,
was this year found guilty of water theft just upstream from those gauges at Brewarrina.
Anthony Barlow, another person named in the program,
was found guilty and fined $190,000, for water theft just upstream again.
Since
the Natural Resources Access Regulator (NRAR) was formed in NSW in
2018, 15 additional charges have been laid in these locations across the
state for water theft and related actions, according to an NRAR
spokeswoman.
Emma
Carmody, a lawyer at the Environmental Defenders’ Office, said the
criminal prosecutions do not represent how widespread water theft has
been.
“I’d actually go so far as to say that this situation
pre-2018 was catastrophically bad in those northern catchments in
relation to compliance and enforcement,” Dr Carmody said.
Irrigators deny water theft is a significant issue in the missing water mystery.
“I
think if people are saying, ‘oh, well, this is about water theft’, then
what they’re doing is really just trying to find someone to blame
rather than trying to find solutions,” said Steve Whan, the CEO of the
National Irrigators’ Council.
It’s probably impossible now to
calculate the true scale of water theft over the seven years analysed by
the Wentworth Group, but it’s unlikely to explain much of the
shortfall. And whatever role it played, there are other key suspects in
the case of the missing water.
Clue two: shadow take
Travel further upstream along the Macquarie River towards Dubbo, and you land in the internationally protected wetlands of the Macquarie Marshes.
It’s
one of the largest remaining inland, semi-permanent wetlands in the
Murray-Darling Basin and supports more than half a million birds in a
large flood.
In the vast flat landscape, decent rains cause water
to spill over the banks of the Macquarie and its tributaries and spread
as far as the eye can see.
In
a landscape so flat, structures like roads, engineered channels and
small levee banks can divert staggering volumes of floodwater —
potentially shepherding it across a farmer’s fields where it is left to
soak into the ground, or even pumped into dams.
This water taken by irrigators and graziers from the floodplains — rather than from the rivers — has hardly ever been measured.
Using satellite imagery, flood paths appear guided by seemingly innocuous structures, or completely cut off by others.
Richard
Kingsford is a river ecologist at the University of New South Wales who
has studied the Macquarie Marshes and the impacts of floodplain
harvesting.
He says water that spills over floodplains often
drains back into rivers, and interrupting its flow can have big impacts,
including contributing to the missing flows.
“There are very few
places where we have an accurate estimate of how much water is being
taken from the floodplain. And to me, this has been a yawning gap in the
policy,” he said.
This floodplain harvesting was not always
illegal — so long as the earthworks were approved and the total amounts
taken were within certain limits. But without proper measurement, nobody
can be sure, and the volumes taken were unknown.
The idea that
floodplain harvesting could explain some of the missing water fits with
the data in the Wentworth Group’s report. In late 2016, there was a
flood in some parts of the basin and despite there being much more water
in that period, the shortfall remained high.
“During
the wet sequences, which haven’t been frequent … I think it’s a matter
of legitimate disquiet that many have about the failure to really bring
those floodplain harvesting schemes into the calculations,” says
Professor Vertessy.
“It’s well past the time that we should have a full fix on that,” he said.
In NSW, where the potential for floodplain harvesting is the biggest, rules are now being implemented to measure it.
Steve Whan from the National Irrigators’ Council said the new rules would help reduce shortfalls in future analyses.
“We’re
seeing extensive work done to improve measurement, including bringing
floodplain harvesting into a volumetric system … And all those things
are really important steps. Many of them are still only partway
through,” Mr Whan said.
Clue Three: The cash splash
If we head all the way to southern NSW, we see a completely different clue.
Billions have been spent subsidising “efficiency measures” to help farmers save water there.
That
can be done by upgrading old irrigation systems to deliver water
directly to roots, or lining water channels, for example. Then about
half of the water saved by the farmers gets handed to the government for
the environment.
But according to some experts, the
“inefficiencies” prior to the upgrades just meant some of the water used
by irrigators flowed back into the rivers. The upgrades mean that
“return flow” stops happening.
“So when you say ‘I’ve saved all
this water’, the question is what was it doing before it was saved?”
said John Williams, another co-author of the Wentworth Group report and
former head of the CSIRO’s Division of Land and Water.
In
a report published in 2019, Professor Williams estimated that at least
280 billion litres of water per year might have been lost from the rivers — and are unaccounted for — due to this problem.
“That must be a major reason that we’re not getting the flow regimes that we need,” Professor Williams said.
The MDBA commissioned its own analysis of the issue and
concluded the loss of return flows was reducing water in the rivers by 121 billion litres a year.
They
say that review shows the reduction in return flows is not a
significant factor and does not impact the outcomes of the basin plan.
“The most comprehensive analysis suggests it is an issue, but not a huge one,” said Professor Vertessy.
Clue Four: Climate change
There is one issue, however, that most experts do agree is a major reason for the missing water in the basin.
“The MDBA considers a changing climate to be the primary contributory factor,” said the MDBA’s Vicki Woodburn.
Since
the basin plan was introduced, heat records across the area have been
broken in four of the eight years. The last three years have been the
hottest ever recorded in the basin.
According
to the South Australian royal commission into the Murray-Darling basin
plan, the MDBA “completely ignored climate change” when determining how
much water needed to be saved.
If true, that means the overall
target may have been set too low — that more water needs to be recovered
from irrigation to save the river system.
But the same models
used to set those targets have also been used to manage the rivers, and
now to calculate how much water should be in the rivers. And by
inadequately accounting for climate change, those models are likely
over-predicting how much water is being recovered.
Climate change
means more water is likely being lost between gauges, as it flows along —
lost into the dry river beds and the hot air.
“The river models
that project where the water will be in the rivers haven’t accounted for
things like greater evaporation of water,” said Professor Pittock.
Professor Vertessy said most people were surprised by the magnitude and speed of the changes seen across the basin.
“I
think a very important thing to appreciate is that we’re in a very
different hydro-climatic sequence than we ever would have envisaged at
the time of the architecting of the basin plan,” he said.
Clue five: The water was never there
In a twist worthy of any whodunnit, could it be that some of the missing water was simply never there in the first place?
According
to the Wentworth Group, the government modelling used to predict how
much water we should see in the river has some fundamental flaws which
likely exaggerate the volumes.
For example, in 2018,
the Murray-Darling Basin Authority found its modelling “has trouble predicting low flows”.
That
meant that when water stopped flowing in the river, the model would
still show water flowing — something that could have been particularly
problematic over the past seven years when low flows were very common.
If true, it likely means much more water needs to be recovered to save the system to get the same outcomes.
The
Wentworth Group scientists say they are confident they applied the
modelling as best as was possible, and Rob Vertessy, who advises the
MDBA on science, agrees.
“Given their intent, which is to make a
comparison of expected flows and those which were realised, then, yes, I
think it’s as solid as any approach you could adopt,” he said.
But
the MDBA has some reservations. “While the Wentworth Group has
partially accounted for the climate and as-yet-unfinished basin plan
implementation, both effects are still present in the analysis and
inflate the outcome,” said Vicki Woodburn.
Everyone seems to be on the same page about how much better the modelling needs to be.
“The
MDBA is working to achieve this improved modelling, however it requires
further investment and would be done in collaboration with all basin
governments,” said Ms Woodburn.
“This type of analysis should be a
fairly routine thing, but in effect, it’s a significant research
project,” said Professor Vertessy.
But Wentworth Group scientists are scathing of the lack of adequate modelling and monitoring of flows.
“You
can’t manage properly what you’re not measuring. And it’s concerning
that the governments haven’t been measuring the … real water in the
rivers against their flow targets,” said Professor Pittock.
What it all means
If there’s less water in the rivers than we ever planned for, what’s to be done about it?
Irrigators say the response should not be to buy more water from farmers, as that would cost too many jobs.
“If
we think about changes to [sustainable diversion limits], then we also
have to then think about what impact it has on those things as well,”
said Steve Whan from the National Irrigators’ Council.
Mr Whan
wants environmental targets to focus more on “complementary measures” —
measures of environmental health, rather than volumes of water.
The
MDBA itself says we need to wait until more of the basin plan is
enacted before we think about changing the recovery targets, or
“sustainable diversion limits” (SDLs) — which are set for review in
2026.
“The basin plan is still not fully implemented so it is too early to suggest the SDLs need to change,” says Vicki Woodburn.
But
Professor Vertessy, who advises the MDBA, thinks this sort of shortfall
could contribute to a rethink of the long-term water recovery targets.
“We
may have to — I think everyone would accept that these sustainable
diversion limits aren’t quantities which you ossify for posterity,” he
says.
“They’ve got to be adjusted to fit in with the new climate realities and the social preferences of the day.”
And the scientists say whatever the response to the findings, something has to give.
“The current basin plan tries to pretend that we can do everything with a smaller and smaller cake,” says Professor Pittock.
“What
this really means is that society is going to have to make some hard
choices. How much irrigated agriculture do we want as a society versus
how much do we want to retain by way of wetlands and ecosystems [or] of
sites of cultural value to Indigenous people?”
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