Which type of flume is most common for measuring flow?

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

Answer: (D)

Open-channel flow is measured with devices that tie water level to discharge. The Parshall flume is the most common because its geometry creates a predictable relationship between the upstream head (water level) and the flow over a wide range, while staying relatively free of debris and needing little maintenance. Its converging section speeds up the flow and its throat provides a stable, repeatable flow condition, which makes calibration straightforward. Installation is versatile—it works in buried conduits or open channels—and you measure the head with a stilling well to convert height to flow using standard charts or equations. Other flumes exist, but they’re more specialized or less practical for routine wastewater use, whereas the Parshall flume combines reliability, simplicity, and a well-established measurement relationship that’s widely adopted.