Four years ago, Broken Hill was in the grip of a water shortage.

A ban was placed on pumping from the Barwon River in order to secure drinking water for communities in the far west of New South Wales.

In the midst of that ban, irrigator Anthony Barlow instructed his operations manager to switch on the pumps at Burren Downs, a property near Mungindi on the NSW border with Queensland.

Barlow has pleaded guilty to three offences — one count of pumping during an embargo and two counts of pumping without a properly operating meter.

He is facing close to $750,000 in fines if he gets the maximum sentence.

But in his sentencing submission — arguing for the lower end of the scale for penalties — Barlow told the NSW Land and Environment Court he was given the green light to pump almost 153 Olympic swimming pools of water during the dry spell by the then state Nationals water minister Kevin Humphries.

Barlow argued the minister, who is invested with the power to determine when pumping can occur, told him in person the ban had been lifted.

It is a claim Mr Humphries previously strongly denied.

Barlow pumped for two days before being alerted to ban

In the autumn of 2015, Broken Hill was suffering.

The Sydney Morning Herald reported the nearby Menindee Lakes resembled "big sandpits".

As part of efforts to protect the water supply further down, a domino effect snaked back up the river system in the form of a temporary ban on pumping water for irrigation.

That ban — officially known as an embargo — included the Barwon-Darling River and the property Burren Downs, outside Mungindi.

According to court documents, Barlow, who was the general manager of Burren Downs, was planning a summer cotton crop over two fields.

He had what's called a "turkey nest" dam, where the walls rise up from ground level. At the time it was about half full.

An aerial shot of the Burren Downs dam. ( Four Corners )

On May 16, while the ban on pumping was in place, Barlow instructed a member of staff to switch on the pumps that took water from the Barwon River and delivered it to the dam.

The two pumps whirred continuously for two days, until Barlow got a phone call.

It was the Senior Water Regulation Officer from river operator WaterNSW, Richard Wheatley, alerting Barlow that there was a ban in place.

Within an hour the pumps were powered down. It's estimated Barlow had taken about 381.62 megalitres of water. To put that amount in context, a megalitre is 1 million litres of water.

Barlow had moved the equivalent of — at an estimate — almost 153 Olympic swimming pools of water from the river into his private storage.

The pumps on Burren Downs were connected to a meter, which had been installed to record the water take.

The meter was supposed to show how much of the water licence had been used up — including for billing purposes — but it was not working properly.

Later that same month on May 29, the ban on pumping was lifted.

That evening Barlow organised the pumps to be switched back on at Burren Downs.

This time they operated for four days.

It's estimated the take was about 512.52 megalitres.

While pumping was allowed in this instance, the take in both cases can only be an estimate.

That is because the water meter, connected to the pumps, did not record a positive reading in either case.

Barlow was planning a summer cotton crop, according to court documents. ( Four Corners )

Questions about Burren Downs were first publicly raised by the Four Corners program Pumped in 2017, which focused on water compliance in the Murray-Darling Basin.

Last year under the New South Wales Water Management Act 2000, Barlow was charged with a series of criminal offences.

He pumped during a ban. And he pumped without a properly working meter, twice.

These are "tier two" offences, according to the act. The punishment is a financial penalty.

The more serious "tier one" offences under the act can carry a prison term.

Originally Barlow's parents — the licence-holders Frederick and Margaret Barlow — were also charged.

But at the end of last year Barlow pleaded guilty to all three offences and the cases against his parents were dropped.

He faces a maximum fine close to $750,000, but it could end up being more if the judge accepts that the penalty applies each day that the pumping occurred and makes a cumulative total.

Barlow told the court that if he knew the embargo was in place he would not have pumped.

But he said the water minister at the time, Mr Humphries, had told a meeting of water users that the ban had been lifted.

Court hears former minister said 'pump unless told otherwise'

Along the Murray-Darling river system water users hold meetings about the state of the waterways and the conditions for irrigators to access water for their land.

Barlow was part of a water users group that stretched from Mungindi down to Menindee, south of Broken Hill.

The Annual General Meeting for the group was held in Bourke, in western New South Wales on March 25, 2015.

Mr Humphries had been charged with the water portfolio for just shy of a year and was present at the water users meeting.

Barlow's affidavit to the court records his version of events at that meeting, using the phrase "words to the effect" for the quoted paragraphs.

"There is currently no embargo in the Barwon-Darling," the then-minister is quoted in Barlow's affidavit as telling the group.

Barlow recalled someone asking why the group was only hearing about that fact now.

He further recalled Mr Humphries responding: "It is on a flow-by-flow basis and if there is a requirement downstream for water, if a flow is deemed to be beneficial, it will be embargoed. But if it isn't, it won't be embargoed".

"In a regulated system you can't pump supplementary water unless you are told you can pump. In an unregulated system assume you can pump unless told otherwise."

This was an important distinction.

The water was split into different areas. The regulated system referred to the part of the river where dams and weirs were able to be manipulated for the flow of water.

But Burren Downs was in the unregulated system.

Barwon MP Kevin Humphries was the water minister at the time. ( ABC News: Gavin Coote )

Mr Humphries, according to Barlow's statement to the court, had just told water users "you can pump unless told otherwise".

Barlow's statement recalls three separate occasions during the meeting where Mr Humphries asserted this.

"I remember watching him lightly hit the table with his hand to make the point as he said it," Barlow stated in his affidavit.

According to the defence submission, notes of the meeting were taken by Andrew Scott who worked for the Office of Water.

The submission said that Mr Scott recorded Mr Humphries' statement, that there was no embargo, and on further questioning the minister is quoted as saying: "You're not listening … there's no embargo".

The defence put the view that no representative from the Office of Water or WaterNSW sought to correct that statement, and Barlow believed the minister and thought the ban had been lifted.

Those prosecuting Barlow pointed out that in the period following the meeting, and before the pumps were switched on, he received two emails stating the ban remained in place.

Barlow told the court he did not remember reading the emails, and emphatically repeated that if he had known he could not pump, he would not have done so.

In his defence he said he was managing a number of properties simultaneously at the time, and relied on the advice from the minister.

But he was also the vice-chairman of his water users group, and prosecutor Sarah Pritchard SC told the court she disagreed with the notion that he was not aware he was doing something illegal.

"I suggest to you, that this is implausible evidence."

Prosecutor Sarah Pritchard SC with colleagues outside the sentencing hearing. ( ABC News: Anna Henderson )

Barlow rejected that assertion but he acknowledged he should have made further checks about whether it was legal for him to pump.

"I still have a conscience about people further down," he told the court.

Barlow further said in his written statement to the court that he knew the Government was required to keep "a certain amount of water available in Menindee Lakes for Broken Hill's water supply and they could do this by imposing pumping restrictions on irrigators upstream".

Three days after the water users meeting, the NSW state election was held.

Mike Baird's Liberal-National government was returned.

In a post-election reshuffle, Mr Humphries was dumped from Cabinet.

He did not provide a witness statement or affidavit to the court proceedings.

But following the Four Corners broadcast in 2017, Mr Humphries denied that he had told irrigators they could access water during a water embargo.

"At no stage did I articulate such a claim, as anyone who attended will confirm," he said.

He also provided a statement to a NSW investigation into water compliance in the aftermath of the Four Corners report.

"I have never said that to anyone either publicly or privately," he was quoted as saying.

When contacted again by the ABC about the evidence in the Barlow sentencing hearing last week, Mr Humphries said he did not comment on court proceedings and hung up the phone.

A map showing Burren Downs and the Barwon River. ( ABC News )

Meter shows zero water was pumped

As mentioned, there was a measure in place on Burren Downs to work out how much water was being taken from the river.

It was a meter.

In this case it was the AgriFlo Series 3 meter.

It uses sensors to pick up the velocity through ultrasonic waves that measure the particles that flow through the water.

An example of the AgriFlow Series 3 water meter. ( Envco )

It calculates how many megalitres of water are being drawn and is used to ensure a water licence holder is not going over the amount they are legally allowed to take.

It is also used to calculate how much the water user owes.

But in both instances in May 2015, when the Burren Downs pumps were operating, the meter was not accurately measuring the amount of water being pumped.

The meter recorded either zero or a negative number, according to the court documents.

According to the agreed facts, at the end of May 2015, after both pumping events, WaterNSW investigators went to the farm to inspect the meter which was not working.

Barlow suggested the sensor leads for the meter (which led to each of the two pumps) might be around the wrong way.

He then removed and switched the plugs over, at which point the meter started recording.

The investigators asked whether he had previously swapped the leads around.

"No I didn't," Barlow replied.

"I don't touch the meter."

In his defence submission on sentencing, Barlow's lawyers stated that one of his employees had unplugged the cables and that worker "cannot recall if he checked that he inserted the sensor plugs back into their correct plugs or not".

There were two offences under the Act for taking water while metering equipment was not operating properly.

The maximum penalty for the dual breach is close to half a million dollars.

A map of the broader Mungindi locality. ( ABC News )

Barlow 'prepared to pay' for water not purchased

The prosecution argued the criminal penalties in the Water Management Act were put in place for a serious reason.

The sentencing submission from WaterNSW includes an excerpt from a speech to the NSW parliament by the former Labor water minister Phillip Costa outlining the reason for the law, from back in 2008.

"With New South Wales suffering from the worst drought on record, it is critical that water is used by those lawfully entitled, and extracted according to licence conditions," it read.

"Water theft directly reduces the water available to users and the environment.

"To put it simply, water theft is not a victimless crime."

The speech further makes a comparison between different categories of rural crime.

"Stock theft has traditionally been regarded in the bush as a low act, and these new penalties send the message that taking water illegally should be regarded the same way."

But Barlow's lawyers argued the court was not presented with "any evidence of environmental harm".

And the sentencing submissions from his legal team further took issue with the characterisation of the crime as "theft" or stealing, because those words do not appear in the actual Water Management Act.

Anthony Barlow in June 2014. ( Cotton Australia )

Barlow told the court he did not think he had profited from pumping the water, and from water statements it appeared the unmetered take had been deducted from his account.

But he also offered a further step, if the court found the water was not purchased.

"I'm absolutely prepared to pay for it," he told the court.

"If I knew there was an embargo in place I would never have pumped."

"I absolutely stand here today and accept responsibility for knowing about the embargo."

On the state of his meter, Barlow said: "I should have had it checked, yes".

Prosecutor Sarah Pritchard noted that water is a "high-value, tradeable asset for individuals, farmers and industry".

"Water offences of this kind are difficult to detect, investigate and prosecute successfully," she said in the prosecution's sentencing submission.

While acknowledging the offending was not in the worst category, the prosecution argued it should be treated as "serious".

Barlow's Senior Counsel David Buchanan maintains his client made an "honest mistake".

"The manner in which that mistake arose is a highly relevant factor to the level of punishment required in this case," his submission on sentencing reads.

The Chief Justice of the Land and Environment Court, Brian Preston, now has a three-month window to decide on an appropriate sentence.