q = flow at vertical
The Mid-section method also divides the cross-section into individual flow segments. With the Mid-
section method, the segments are not between verticals but are defined by half of the distance to
neighbor verticals in each case. For this reason, the first and last verticals should be as near to the
edges as possible (i.e., left edge of water (LEW) and right edge of water (REW)). Boundary
conditions dictate the proximity of the first and last vertical to the edge of water.
Experience shows that the Mid-section method gives more exact results compared to the Mean-
section method so it is the default setting. Figure 16 shows the definitions and equation for the Mid-
section method.
Figure 16 Mid-section method
Where:
m = station number
n = total number of stations
V = velocity at vertical
b = distance to vertical from bank
h = depth at vertical
q = flow at vertical
Profiles and measurements
Profiles can be set up for streams or conduits. Figure 17 shows an example of a typical profile shape
in a conduit. In a typical profile, velocity is less near a wall or edge than at the center and decreases
near the surface. Multiple velocity measurements in the profile are averaged to calculate the total
flow. Measurements for conduit profiles are made from the bottom up. Measurements for stream
profiles are made from the top down or bottom up.
In the Main Menu, select Profiler. The meter prompts for the operator name, the type of profile
(stream or conduit) and the profile name. Do the instructions for the selected profile type.
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