Reply To: ADCP measurements in regulated flow conditions

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Hi. I am not familiar with the expression “regulated flow conditions”. Does it mean that discharge is changing rapidly due to opening/closing of upstream hatches/locks/turbines in an upstream dam? If so, I really don’t know. Perhaps, if you have 4-6 (or more) transects and you see a linear trend, you could calculate Deviation from trendline (and not from mean) and use the MPRR condition on that deviation?

For a steady flow NVE (Norway) have 3 conditions

– Even number of transects

– 12 minutes at least of total time (this comes from USGS + Qrev/QrevInt)

– No “red transects” in WinRiver, that is, no transect more different from the mean than the MPRR condition in WinRiver (

The last condition is encouraged also when using RSL (with Sontek ADCPs), even if the operator need to bring a table to check MPRR versus number of transects. For a very bad site, we may allow “red transects” after collecting 8-12 transects, if it seems obvious that we will not manage to avoid the “red transects” within a sensible amount of time.

In addition, if we QrevInt to process data on site, and we use the Oursin uncertainty model in QrevInt. If we see that COV (covariation, difference between transects) is not the biggest source of unsertainty, then we know that we have enough transects, and that to reduce uncertainty we need to improve somtehing else.

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