Parshall Flume Flow Rate Calculator

In this tutorial, we will discuss the Parshall Flume and how to calculate its flow rate using the parameters of throat section width and upstream depth. A Parshall Flume is a type of flow measurement structure that is used to measure the flow of fluid in open channels. This concept is particularly relevant to the fields of civil engineering and physics, especially in relation to water resource management and hydrology.

Parshall Flume Flow Rate Calculator
Parshall Flume Flow Rate Calculator Results
Flow Rate = ft3/s

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Example Formula

Parshall provided a set of empirical equations to estimate flow rates based on the upstream depth (Ha) and the throat section width (W). Here is one such equation for a 1-foot Parshall flume:

Q = 0.992 Ha1.547


  1. Q: The flow rate through the flume
  2. Ha: The depth of the water at the upstream (approach) section of the flume

Who wrote/refined the formula

The Parshall flume and the associated empirical equations for flow rate estimation were developed by Ralph L. Parshall, a hydraulic engineer at the U.S. Department of Agriculture, during the 1920s and 1930s.

Real Life Application

Parshall flumes are extensively used in irrigation channels, wastewater treatment plants, and industrial discharge sites to measure the rate of fluid flow. These measurements are critical for proper management and control of water resources.

Key individuals in the discipline

Without a doubt, Ralph L. Parshalls contributions to the field of fluid dynamics and hydrology were significant. His invention of the Parshall flume has facilitated accurate and reliable measurement of fluid flow in numerous applications, greatly aiding in the management of water resources.

Interesting Facts

  1. The design of the Parshall flume takes advantage of the principles of fluid dynamics to create a maintenance-free flow measurement device that doesnt require any external power.
  2. The use of the Parshall flume has revolutionized the measurement of fluid flow in open channels, helping humanity better manage and conserve water resources.
  3. Despite being developed nearly a century ago, the Parshall flume remains one of the most widely used devices for measuring flow in open channels.


Understanding the Parshall Flume Flow Rate and how to calculate it is crucial in fields such as civil engineering and physics, particularly for water resource management. Despite being nearly a century old, the Parshall flume remains a key tool in these fields, demonstrating the lasting impact of effective scientific and engineering solutions.

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