Historically, the measurement of flow in open channels has been undertaken using civil structures such as flumes and weirs. Whilst these structures do provide a reasonably accurate measure of the stream flow, in practice, flumes and weirs often suffer from neglect over time and provide less than favourable conditions for flow measurement with stage measurements and rating tables. This may be particularly the case for structures that are several years (if not decades) old, and were designed for measuring different flow rates than may exist today.
The use of "area-velocity" methods, such as that provided by the Doppler ultrasonic MACE AgriFlo to measure flow in open channels, not only negates the need for costly civil structures, but also increases the overall accuracy of the measurement. Furthermore, with a MACE AgriFlo, it is possible to measure flow in open channels of an irregular shape, such as earthen channels or those cast in situ.
Where sites exist that have less than favourable hydraulics for accurate flow measurement, the MACE AgriFlo can be calibrated with FloCom+ software for even greater accuracy.