SUSTAINING THE BASIN | METERING
Meters, telemetry and accuracy
December 2015
Southern Valleys Metering Project
Telemetry
The Southern Valleys Metering Project involves
installing 700 new regulated, unregulated and
groundwater meters across the Murrumbidgee,
Murray and Lower-Darling valleys.
Meter readings are recorded every 15 minutes and
the telemetry will transmit meter data to databases
hourly, daily or weekly, allowing meter readings to
be accessed remotely.
The new meters will be fitted with telemetry to
provide water usage data.
WaterNSW is currently consulting with our
Customer Service Committees, looking at improved
ways of assisting customers to leverage the use of
this technology with their farm irrigation systems.
Accurate metering is crucial to good water
management and important for fairness and equity
amongst our customers. For landholders and
irrigators this will mean improved water security and
delivery, with opportunities for better service.
Electromagnetic flow meters
Electromagnetic flow meters (also known as
magflow meters) have been selected on pipe or
closed conduit systems for their accuracy and their
comparatively low maintenance. This type of meter
does not have any moving parts that can cause flow
restrictions in the pipe.
Electromagnetic meters are generally less
susceptible to sand and vegetation contamination
than mechanical meters which have been the
predominant meter type in use along the Murray
system. In some situations meters of a nonelectromagnetic type may be used where site
conditions dictate this requirement or it is more cost
efficient to do so.
The on-site meter display will show customers their
extraction (or pump) rate and the total water volume
extracted.
Accuracy
New meters are factory tested and to ensure they
conform to national and NSW standards prior to
installation. Each meter is issued with a certificate of
calibration.
The National Metering Standards have strict
accuracy requirements of ± 2.5% under laboratory
test conditions and ± 5% under field conditions.
Typically compliant meters far exceed these
accuracies.
During the initial ‘pilot’ to the state wide metering
project 120 of the 500 new meters were installed in
series with existing mechanical meters.
The results of this study were independently
analysed. While the bias of old meters averaged at
around 3% under registration, the main finding was
the scatter of accuracy. There is presently
significant inequity where some customers are
receiving up to 70% more water than they are
entitled, while others are receiving 70% less.
In a separate study, Thiess Hydrographic Services
were engaged to do independent in field testing of
eight Magflow meters that customers claimed were
“reading more than my old meter”. The Thiess test
rig demonstrated that the eight new meters all
exceed national metering accuracy standards
of ± 2.5%.
Please see overleaf for accuracy testing results
graph and images
Meters, telemetry and accuracy
Figure 1: Distribution of meter error for dual metering sites
Important findings
•
Only 20% of the existing meters were recording within the ± 5% accuracy limits
•
10% of existing meters were recording at least 15% under the actual use
•
10% of existing meters were recording at least 10% over the actual use
Please see the Review of Meter Accuracy information sheet for further information
Figure 2: Thiess Hydrographic Services Testing
The Southern Valleys Metering Project is funded under the
Australian Government’s Sustainable Rural Water Use and
Infrastructure Program as part of the implementation of the
Murray Darling Basin Plan in NSW.
© State of New South Wales through the Department of Industry, Skills and Regional Development, 2015. You may copy, distribute and otherwise freely
deal with this publication for any purpose, provided that you attribute the NSW Department of Primary Industries as the owner.
Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (December 2015). However,
because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency
of the information with the appropriate officer of the Department of Primary Industries or the user’s independent adviser.
Published by the Department of Primary Industries. JTN 13769_5
2
NSW Department of Primary Industries, December 2015