Reply To: Difference in Meas Q between calculations of flow WinRiverI ? vs WinRiverII/Qrev

Untitled Forums International Hydrometry Network Flow Measurements ADCP Difference in Meas Q between calculations of flow WinRiverI ? vs WinRiverII/Qrev Reply To: Difference in Meas Q between calculations of flow WinRiverI ? vs WinRiverII/Qrev

#345
AvatarJeffDH
Participant

    Hi Asa.  You have an advantage on me as I have never used WinRiver I!!!  But yes, WinRiver I used a less conservative sidelobe cutoff calculation based (I think) on the average depth rather than the individual beam depths,   The results are often acceptable but you can never tell when there might be bottom-return base bias in the velocity data, nor how much it might impact the discharge calculations.

    The current version of WinRiver II allows you to select the WinRiver 1 style sidelobe cutoff calculations – be warned, this is a program level setting that will impact all measurements, not one that can be changed for a single measurement.  To select this setting, go to File, Properties, General Configuration, and select the checkbox for ‘WinRiver I Sidelobe Calculations’.  When I do this for the Molholm000r measurement, I get an average measured Q of 61.732, precisely matching the value in your spreadsheet.  If you do this, don’t forget to change that checkbox back when finished….

    The impact of this change, and the areas near the bottom where sidelobe contamination is likely present, can be visualized by viewing the ‘Intensity by beam’ contour plot.   I’ve attached a comparison graphic showing them side by side, with the areas of probable sidelobe contamination circled in red for the WinRiver I version.

    Hope this helps.  Jeff

    WR1 vs 2