Bazins Weir Flow Calculator

Understanding the flow of water over a weir is crucial in the fields of fluid dynamics and civil engineering. A weir is a type of barrier across a river that alters its flow characteristics and measures the flow of water. The French engineer, Henry Bazin, developed a formula to determine this flow rate or discharge over weirs. This tutorial will guide you through Bazin's Weir Flow formula and its practical applications.

Bazins Weir Flow Calculator
Bazins Weir Flow Calculator Results
Water Flow Rate = m3/s

Please provide a rating, it takes seconds and helps us to keep this resource free for all to use

[ 10 Votes ]

Example Formula

The Bazin's Weir Flow formula is as follows:

Q = C × L × H3/2


  1. Q is the flow rate or discharge (in cubic meters per second).
  2. C is the discharge constant or Bazin's constant (unitless).
  3. L is the width of the weir (in meters).
  4. H is the head on the weir (in meters).

Who wrote/refined the formula

This formula was developed by Henry Bazin in the late 19th century. Bazin was a French engineer and hydraulics specialist, known for his work on the flow of water over weirs and through open channels. His formula has become one of the standards in hydraulic engineering and continues to be used worldwide.

Real Life Application

This formula is commonly used in the field of hydraulic engineering to measure the flow of water in rivers, canals, and other water bodies. It's crucial in designing and monitoring dams, weirs, and other water control structures. For example, engineers may use it to calculate the flow rate of a river to design an effective and safe weir for a proposed hydroelectric power station.

Key individuals in the discipline

Henry Bazin is the key figure associated with this formula. His work in the field of hydraulic engineering has been instrumental in advancing our understanding of water flow in various settings. His contributions have helped to shape the practices and standards in civil and environmental engineering.

Interesting Facts

  1. Despite being over a century old, Bazin's formula continues to be used today due to its accuracy and simplicity.
  2. The flow over weirs is a critical aspect of many environmental and civil engineering projects, influencing everything from the design of dams to the management of water resources.
  3. The principles of weir flow have been instrumental in the development of renewable energy sources, such as hydroelectric power.


Understanding the principles of fluid dynamics, specifically the flow of water over a weir, is of great significance in the realms of environmental science, civil engineering, and even renewable energy generation. Bazin's Weir Flow formula has stood the test of time, providing engineers and scientists with a reliable method to measure and predict water discharge. The formula not only helps manage our water resources more effectively but also contributes to the development of sustainable energy solutions.

Physics Calculators

You may also find the following Physics calculators useful.