Increasing uptake of irrigation telemetry masks accuracy concerns

The Inspector-General of Water Compliance found in 2021-22, 61 per cent of all Victorian non-urban meters employed telemetry, up by 16pc on the previous financial year. That accounted for 70pc of the total water take.

Telemetry automatically collects, transmits and measures data from remote sources, using sensors and other devices to collect and transmit it back to a central location.

Central Goulburn Water Services committee chair Peter Hacon said he was more interested in knowing how accurate the metering system was, rather than the uptake of telemetry.

"We can put on telemetry, or approved meters, but how accurate are they?" Mr Hacon said.

"Are we just grandstanding in saying we have all this telemetry, or are we metering to Australian standards?"

He said G-MW was supposed to do 10 tests a year, but he'd never seen any results.

"Let's see the test results," he said.

"Telemetry is a great political flag to wave, but is it doing any good?"

He said he found it very hard to believe IGWC figures that 98 per cent of take in the Victorian part of the Murray-Darling Basin was metered.

Mr Hacon also questioned the figure that 90 per cent of the total take was through meters compliant with the AS4747 national standard and contemporary (grandfathered) meters, which were accurate to +/-5 per cent.

And Loddon Valley WSC deputy chair Laurie Maxted, Boort, said he also had concerns about the accuracy of meter readings.

"There is a big percentage of meters that aren't even being used - they have gone through modernisation and there are parts of the system that aren't being used," Mr Maxted said.

"I've always been worried about the recording and accuracy of meters - the accuracy of the meters has never been right."

He said prior to modernisation, water authorities had claimed all meters were losing a megalitre a year, through seepage.

'That's absolutely ludicrous - we had 16 or 18 meters and you could not tell there was any seepage out of any of them, and yet that got recorded as water wastage in getting the upgrades done."

Meters could be affected by things like a build-up of rubbish in the outlet, he said.

Mr Maxted claimed initial tests to calibrate the accuracy of the meters were done in perfect conditions in a factory.

"There were no ripples, there was no wind, it was a perfect situation," he said.

GMW Strategy Services Planning general manager Steven Abbott said water was a valuable and tradeable asset for customers.

Everyone needed to ensure it was measured accurately so its real value could be maintained, he said.

"Over the past year, GMW inspected approximately 4500 meters across its water delivery network," he said.

"We also have a capital meter replacement program that is worth $1.6 million annually.

"This helps ensure our meter fleet is performing smoothly and capturing the data we need."

There were still 1458 Dethridge wheels in the GMW's water delivery network.

Of those, 573 were used during the 2022/23 irrigation season.

Other WSC chairs welcomed the telemetry roll out.

Rochester-Campaspe WSC chair Richard Anderson said telemetry allowed remote reading, but the technology was not warranted in all cases.

"That's more to do with cost - if a meter is only used once a year for 10 megalitres of water, the cost wouldn't stack up," he said.

He said the telemetry take up percentage was "pretty good - but I would be more interested in the outlets that aren't metered, not whether they have telemetry or not.

"We have done pretty well in Victoria, there are some states that don't have meters at all."

Torrumbarry WSC chair Andrew Leahy said telemetry was an improvement on manual reading.

He said it allowed him to know, over the phone, what water flows his dairy business was getting on its paddocks.

"It gives you real-time information," he said.

Goulburn-Broken WSC chair Craig Madden said metering had always had its challenges when it came to compliance policy, as well as the cost of meeting compliance and negotiating costs versus benefit.

"Telemetry monitoring, I believe is showing promise, but once again the landscape in the diversions side of G-MW is a challenge," he said.

"There are other nuances to this issue such as cost impediments to customers as to what level do you go to measure every litre of water?

"Are there other options like 'deeming' (determining) usage by pipe diameter, auditing and compliance and the benefits you get by having GMW staff on the ground talking to licence holders?" he said.

"This is ongoing but the principles driving us are for realistic benefits versus cost, practicality, and quality monitoring in a climate change future where water demand will increase while the resource decreases."