Xylem SonTek FlowTracker2, User Manual

Page: 139 / 308

SonTek – a Xylem brand
FlowTracker2 User’s Manual (January 2019)
138
Station Parameters 8.3.4.1
The Station Parameters that need to be determined before a decision is made on what
velocity method will be used are the station location with respect to the starting point on
the tag line or measuring tape and the total water depth.
Figure 8:28 - Station Parameters
L
4
, is the distance from
the start location on the
tag line or measuring
tape.
D
4
, is the water depth
measured from the water
surface to the channel
bed.
The value of the start location on the tagline or measuring tape is not required to be
zero (0.000m). The station location can also be entered in negative direction, with the
start location at a larger value (e.g. 7.956m) and the end location at a smaller value
(e.g. 0.532m). This feature assist when a measurement is performed from the left bank
to the right bank and then back using the same tag line setup.
Start location of measurement at 0.532m
0.532 1.23 2.23 3.23 3.23 4.23 5.23 6.23 7.23 7.956
Start location of measurement at 7.956m
Point Velocity Measurement 8.3.4.2
The Velocity Method (see Determining Mean Station Velocity ) selected for a station is
based on the water depth, hydraulic conditions and the flow distribution within the
measurement section.
•
The number of point velocity measurements required within a vertical is
dependent on the type of velocity method selected.
•
The point velocity measurements are performed at a defined fractional depth
based on the velocity method selected.
L
4
D
4