Which flow measurement device is commonly described as the most common type for flow measurement?

• A. Knife-edge flume
• B. Palmer flume
• C. Flume
• D. Parshall flume

Answer: (D)

Parshall flume is the most common flow measurement device because its standardized shape and broad measurement range give reliable, accurate readings in open-channel and buried sewer flows. The flow is determined by the head upstream of the throat, which is read with a staff gauge or level measurement and converted to discharge using a widely published rating curve. The geometry is fixed and well-documented, so installation is straightforward and results are repeatable across many sites.

This design handles a wide range of flows without moving parts, and it performs well in typical wastewater settings where debris can be present—if installed with proper upstream straight requirements and a downstream stilling section. That combination of reliability, ease of use, and standardized calibration is why the Parshall flume is favored over other flumes, which may require cleaner conditions, longer straight runs, or have narrower useful flow ranges.