Weir Flow Calculator
Calculate flow rate over weirs using standard weir equations
About this calculator
The Weir Flow Calculator determines the flow rate of water over various types of weirs using established hydraulic engineering equations. This tool is essential for water management professionals, civil engineers, and hydrologists who need to measure discharge rates in open channels, irrigation systems, and water treatment facilities. By inputting weir dimensions and water head measurements, users can accurately calculate volumetric flow rates for design validation, flow monitoring, and regulatory compliance in water infrastructure projects.
How to use
Enter the weir type (rectangular, triangular, or trapezoidal), input the weir dimensions including width and height, then specify the head of water above the weir crest. The calculator will automatically apply the appropriate weir equation and discharge coefficient to compute the flow rate in your preferred units.
Frequently asked questions
What types of weirs can this calculator handle?
The calculator supports rectangular, triangular (V-notch), and trapezoidal weirs, which are the most common types used in hydraulic measurements and water flow control applications.
How accurate are the calculated flow rates?
Results are highly accurate when proper measurements are taken, typically within 2-5% of actual flow rates, assuming standard weir design conditions and calibrated coefficients are used.
What measurements do I need to use this calculator?
You need the weir crest width, weir height, head of water above the crest, and weir type. Some configurations may require additional parameters like side slopes.