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Discharge Tables

Below are the general discharge tables, equations, and minimum / maximum heads for weir plates commonly used in Openchannelflow weir boxes - they are not specific to the various standard weir box / plate combinations offered.  

To determine the actual flow capacity of a standard weir box, verify the maximum head for the box and then use that in conjunction with the tables below.  

For additional weir discharge tables visit the Weir Plate Discharge Tables section.

22 1/2º V-Notch Weir
Minimum Head (ft) 0.20 Minimum Head (m) 0.0610
Miniumum Flow Rate (cfs) 0.0089 Minimum Flow Rate (l/s) 0.2518
Maximum Head (ft) 2.00 Maximum Head (m) 0.6096
Maximum Flow Rate (cfs) 2.811 Maximum Flow Rate (l/s) 76.62
Equation=cfs, ft 0.4970*H2.5
Equation=l/s, m 274.4*H2.5
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30º V-Notch Weir
Minimum Head (ft) 0.20 Minimum Head (m) 0.0610
Miniumum Flow Rate (cfs) 0.0121 Minimum Flow Rate (l/s) 0.3425
Maximum Head (ft) 2.00 Maximum Head (m) 0.6096
Maximum Flow Rate (cfs) 3.824 Maximum Flow Rate (l/s) 108.3
Equation=cfs, ft 0.6760*H2.5
Equation=l/s, m 373.2*H2.5
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45º V-Notch Weir
Minimum Head (ft) 0.20 Minimum Head (m) 0.0610
Miniumum Flow Rate (cfs) 0.0185 Minimum Flow Rate (l/s) 0.5243
Maximum Head (ft) 2.00 Maximum Head (m) 0.6096
Maximum Flow Rate (cfs) 5.855 Maximum Flow Rate (l/s) 165.8
Equation=cfs, ft 1.035*H2.5
Equation=l/s, m 571.4*H2.5
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60º V-Notch
Minimum Head (ft) 0.20 Minimum Head (m) 0.0610
Miniumum Flow Rate (cfs) 0.0258 Minimum Flow Rate (l/s) 0.7310
Maximum Head (ft) 2.00 Maximum Head (m) 0.6096
Maximum Flow Rate (cfs) 8.163 Maximum Flow Rate (l/s) 231.2
Equation=cfs, ft 1.443*H2.5
Equation=l/s, m 798.7*H2.5
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90º V-Notch Weir
Minimum Head (ft) 0.20 Minimum Head (m) 0.0610
Miniumum Flow Rate (cfs) 0.0447 Minimum Flow Rate (l/s) 1.267
Maximum Head (ft) 2.00 Maximum Head (m) 0.6096
Maximum Flow Rate (cfs) 14.14 Maximum Flow Rate (l/s) 400.5
Equation=cfs, ft 2.500*H2.5
Equation=l/s, m 1,380*H2.5
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