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 | ||
| Download The Full Table | Verify weir depth |
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 | ||
| Download The Full Table | Verify weir depth |
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 | ||
| Download The Full Table | Verify weir depth |
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 | ||
| Download The Full Table | Verify weir depth |
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 | ||
| Download The Full Table | Verify weir depth |
