Isco FlowCalc

The open channel flow rate calculator for flumes, weirs, area-velocity & Manning

This app calculates flow rates in open, non-full channels and pipes. Use this app to spot-check the performance of installed flow monitoring systems, or verify that newly installed flow meters are configured correctly. This app includes level-to-flow rate calculations for primary devices and area-velocity flow rate calculations for a variety of conduit shapes.

You can display flow rate units as cubic feet per second (cfs), gallons per minute (gpm), or million gallons per days (mgd). By changing the app settings to SI units, you can display flow rates as liters per second (lps) or cubic meters per hour (m3h). Units for input are inches, feet, millimeters, and meters.

Level-to-Flow Rate Calculations for Primary Devices

Enter the head height to calculate flow rates in the following primary devices:

• Parshall flumes from 1 inch to 12 feet (0.0254 to 3.66 m)

• Palmer-Bowlus flumes from 4 to 30 inches (0.102 to 0.762 m)

• Leopold-Lagco flumes from 4 to 30 inches (0.102 to 0.762 m)

• V-notch weirs: 22.5, 30, 45, 60, 90, 120 degrees

• Rectangular weirs with end contractions from 1 to 10 feet (0.3 to 3.0 m)

• Rectangular weirs without end contractions from 1 to 10 feet (0.3 to 3.0 m)

• Cipolletti weirs from 1 to 10 feet (0.3 to 3.0 m)

Area-velocity Flow Rate Calculations

Enter the head height, velocity, and dimensions to calculate flow rates in these channel shapes:

• Round pipes to 30 feet (10 m) in diameter

• U-shaped channels to 30 feet (10 m) wide

• Rectangular channels to 30 feet (10 m) wide

• Trapezoidal channels to 30 feet (10 m) wide

• Elliptical pipes to 30 feet (10 m) wide

Manning Formula Flow Rate Calculations

Enter the head height, roughness, slope, and dimensions to calculate flow rates in these channel shapes:

• Round pipes to 30 feet (10 m) in diameter

• U-shaped channels to 30 feet (10 m) wide

• Rectangular channels to 30 feet (10 m) wide

• Trapezoidal channels to 30 feet (10 m) wide

Save your frequently-used calculations as Favorites. This handy feature lets you quickly access calculations by site name and map your location when GPS data is available.

All flow rate calculations are based on equations published in the Isco Open Channel Flow Measurement Handbook, Sixth Edition. This definitive reference book, published by Teledyne Isco, is widely used by water and wastewater monitoring professionals. To read the free online handbook, visit flowhandbook.teledyneisco.com.

Disclaimer: The equations used in this calculator were obtained from sources deemed to be reliable. Neither Teledyne Isco nor anyone acting on its behalf makes any warranty with respect to the accuracy, completeness, or usefulness of the app features. Teledyne Isco shall not be held liable for any damages that arise from the use of this app.