SonTek, a Xylem brand
RiverSurveyor S5/M9 System Manual (February 2013)
143
•
Velocity
o
In the
Statistical
calculation, this term includes both uncertainty in the velocity
measurement and the effect of changes in velocity between stations.
o
In the
ISO
calculation, this term includes only the uncertainty in velocity meas-
urements.
•
Width: estimated uncertainty in width measurements.
•
Method: estimated uncertainty from not measuring velocity throughout the entire water col-
umn (velocity near the surface and bottom must be estimated).
o
Used for the ISO calculation only.
•
Number of stations: estimated uncertainty from measuring velocity and depth at a limited
number of locations across the river.
o
Used for the ISO calculation only.
The Discharge Measurement Report shows both uncertainty calculations and the contribution of
each parameter to the overall uncertainty.
