Hach 911 User Manual page 80

Working with Primary Devices
Preferred Head Measurement Point
Upstream Depth
78
Submerged Probe
(Preferred Head Measurement Point)
Upper Transition
Water Surface
"D"
Conduit Diameter
2
Figure 42 Palmer-Bowlus Flume (with Integral Approach)
FLOW
Top View
Throat
Small jump should occur here.
FLOW
Elevation View
Lower
Transition
Downstream Depth