SonTek, a Xylem brand
RiverSurveyor S5/M9 System Manual (February 2013)
145
Mueller and Wagner. SonTek/YSI recommends that this step-by-step procedure is reviewed
prior to attempting a Loop Method measurement using the
RiverSurveyor Live
software.
The Loop Method can be performed using either the PC or mobile
Riversurveyor Live
software.
The procedure is essentially identical. The only difference is the graphical screens available in
the PC software. In addition, following the completion of the loop measurement results will only
be available using the PC software.
Although moving-bed results are available prior to the discharge measurements to be per-
formed, the actual “Loop Correction” will only be applied to discharge measurements in post-
processing (if required). In addition, if the moving bed is determined to be insignificant it will not
be possible to apply the correction to the processed data – this is in accordance to USGS pro-
cedures.
Step-by-step procedure:
1. Start the
RiverSurveyor Live
PC or mobile software and connect to the M9/S5.
2. In the start menu, input all necessary parameters as usual to measure discharge.
3. Calibrate the compass (Utilities menu). A proper compass calibration is required to produce
reliable results when using the Loop Method correction as the compass is used to determine
the tagline azimuth.
4. Establish a starting point in the river. It will be helpful to select this location such that the
boat can easily be controlled when starting and ending a measurement. Keep in mind that
you will need to return to this same location in order to compute properly the moving-bed
speed—the greater the difference between the start and end locations, the greater the un-
certainty in the Loop Method’s results. Also, the point does not need to be located as near
to the bank as a regular discharge measurement.
5. Click on
Loop Method
located in the Utilities Menu of the PC software as shown in Figure
128. It is in the Main Menu when using the mobile software. The instrument will begin pro-
filing.