Weir Flow Calculator
Calculate flow rate over weirs including rectangular, triangular, and trapezoidal weir configurations
About this calculator
The Weir Flow Calculator determines water flow rates over different weir configurations including rectangular, triangular, and trapezoidal designs. This tool is essential for hydraulic engineers, water management professionals, and environmental scientists who need accurate flow measurements for irrigation systems, flood control, water treatment facilities, and stream monitoring. By inputting weir dimensions and water height, users can quickly calculate discharge rates without complex manual calculations, ensuring proper water resource management and system design.
How to use
Select your weir type (rectangular, triangular, or trapezoidal) from the dropdown menu. Enter the required dimensions such as weir width, height, and water head above the weir crest. Click calculate to instantly obtain the flow rate in your preferred units (cubic feet per second, liters per second, etc.).
Frequently asked questions
What is the difference between weir types?
Rectangular weirs measure flow over straight edges, triangular weirs are ideal for low flows, and trapezoidal weirs combine benefits of both designs for varying flow conditions.
How accurate are weir flow calculations?
Weir calculations are highly accurate (±2-5%) when properly calibrated and installed, making them reliable for flow measurement in open channels and water control structures.
What measurements do I need for calculations?
You need the weir width/dimensions, head height (water depth above weir crest), and weir material properties. Some calculations may require approach velocity or channel geometry.