A 2.5-foot fiberglass H Flume with a integral approach section.  Approach sections are rectangular channels having the same cross-sectional shape as the H Flume to which they are part of / attached to.  Approach sections are typically 3 to 5 times the maximum anticipated head (usually assumed to be the flume's length), although longer and shorter approach sections are possible.

Approach sections help to condition the flow prior to it entering the flume. They also serve as a convenient spot in which to mount parameter probes or into which flow conditioing devices (tranquilizer racks, perforated plates, or energy absorbers) can be mounted.