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Evaluation of Low-cost Ultrasonic Flow Meters

Project ID: 6578
Principal Investigator: Bryan Heiner
Research Topic: Agriculture Water Supplies
Priority Area Assignments: 2012 (Climate Adaptation), 2013 (Climate Adaptation)
Funded Fiscal Years: 2011 and 2012
Keywords: None

Research Question

Are relatively low-cost Doppler flowmeters a reliable and cost-effective means to accurately measure flow in open-channel and closed-conduit irrigation water delivery systems?

Need and Benefit

Irrigation project managers are constantly seeking low-cost methods for accurately measuring irrigation deliveries. Acoustic Doppler flowmeters are often an attractive option because they cause no head loss, are easily installed, provide supervisory control and data acquisition (SCADA)-compatible outputs, and can be applied to a wide variety of flow situations. Acoustic Doppler flowmeters are available for prices ranging from about $2,000 to $18,000, depending on the degree of sophistication. One of the relatively new meters in the U.S. market is the low-cost MACE AgriFlo, first developed in Australia. This meter is in the $2,000 price range and is being marketed to U.S. irrigators for measurement of flows at small open-channel turnouts. The meter also has potential uses in larger canals and pipe-flow situations. A similar meter is manufactured by Grayline. Other manufacturers are quickly adding similar products to their lines as the low-cost Doppler meter market rapidly expands.

The Bureau of Reclamation's (Reclamation) hydraulics laboratory in Denver has fielded numerous questions in the last few years from area office personnel and irrigation districts regarding the accuracy and suitability of these meters. Anecdotal evidence from Australian applications suggests that devices such as the AgriFlo meter could fill an important niche in the U.S., but its relatively simple technological approach to flow measurement may also create limitations. This project would undertake a series of controlled laboratory tests and field demonstrations in which several low-cost Doppler meters would be evaluated against other accepted flow measurement methods to determine accuracy, establish limitations on application, and develop firsthand experience with the meters. This study would be a followup to a study performed several years ago in which we evaluated a similar unit, the Unidata Starflow meter.

By conducting a nonbiased evaluation of several low cost meters, Reclamation engineers can help irrigation districts and area office personnel best identify low-cost ultrasonic meters that can be used with confidence. Some may argue that these meters are commercially available and, thus, require no evaluations to determine their accuracies. Unfortunately, this theory is flawed because many manufacturers market their products to sell and not necessarily to provide accurate and reliable results. A nonbiased comparison would remove any sale-increasing slants that may be added to product descriptions. In addition, many manufacturers don't follow their products after installations are complete. This study would allow the meter use to be documented over time to see how accurate meters are in field and laboratory situations.

Contributing Partners

None

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Laboratory Evaluation of Open Channel Area-Velocity Flow Meters (final, PDF, 522KB)
By Mr. Bryan J Heiner and Tracy B Vermeyen
Report completed on July 23, 2012

This paper discusses the results from a series of controlled laboratory tests in which nine area-velocity flow meters were evaluated against a known discharge to determine accuracy and to document ease of use for the hardware and software. Each of the nine meters was individually tested in three open channels including; a 1.5-ft-wide trapezoidal, a 4-ft-wide rectangular and an 18-in-diameter circular channel.
Keywords: flow meter, ultrasonic, area-velocity, doppler

This information was last updated on October 1, 2014
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