Broad Crested Weir Calculator
Calculate the discharge over the weir using our broad crested weir calculator.
What Broad Crested Weir Calculator does
A broad crested weir calculator determines the discharge, or volumetric flow rate, of water passing over a hydraulic barrier. Users input the weir crest width, the upstream water depth, and the height difference between upstream and downstream levels to obtain the flow rate in cubic meters or feet per second. The output provides the discharge coefficient and the resulting flow, allowing practitioners to size weirs for irrigation channels, spillways, or laboratory experiments without manual integration of the standard hydraulic formula. Omni Calculator presents the result alongside the governing equation and a diagram of the weir geometry, making the physics transparent at a glance. Compared with other online weir tools, this version requires only three primary inputs—width, upstream depth, and head height—while offering instant unit toggles and a concise explanation of the discharge coefficient, which many competing calculators hide behind additional parameters or require manual lookup. The interface remains minimal, displaying one equation at a time rather than overwhelming the user with multiple flow regimes or weir types simultaneously.
How to use the Omni Calculator Broad Crested Weir Calculator
- 1
Enter the width of the weir crest in meters or feet
- 2
Input the upstream water depth relative to the crest in the same units
- 3
Specify the height difference between the upstream and downstream water levels
- 4
View the calculated discharge rate and the applied discharge coefficient instantly
Best for
Engineering students and field technicians who need a quick, accurate flow estimate for a broad crested weir without manually solving the hydraulic equation or switching between unit systems.
Limitations
- Assumes horizontal weir crest and steady, subcritical flow conditions
- Discharge coefficient is approximated and may vary with approach velocity or sediment load
- Results are estimates; field verification is recommended for design-critical applications
Broad Crested Weir Calculator FAQ
- Can this calculator handle partially submerged weirs?
- The tool is designed for free-flow conditions; submerged downstream levels require a different formula or additional submergence correction factors not included here.
- What units should I use for the weir width and water depth?
- You may enter width and depth in meters or feet; the calculator converts internally and displays the discharge in the corresponding volumetric units.
- How accurate is the discharge coefficient value shown?
- The coefficient displayed is a standard approximation for broad crested weirs; real-world values can differ based on crest shape, approach flow turbulence, and channel geometry.
- Is the result suitable for regulatory or design submissions?
- The output is a useful estimate for planning and educational purposes, but official engineering submissions should use validated software or consult a licensed professional.
Similar tools
Based on shared tags