Manning Open Channel Design Spreadsheet

The spreadsheet includes US unit versions as well as standard metric versions. Click here for US or Australian versions.

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Manning Open Channel Design Spreadsheet 1

The Manning Formula is used to determine the flow in open channels. The Manning formula is given below;

Manning Formula for Open Channels or Pipes

V = Average Water Velocity (m/s)

Q = Flow (m³/s)

n = Manning's Roughness Coefficient

A = Cross Sectional Area of Pipe (m²)

P = Wetted Perimeter of Pipe (m)

S = Hydraulic Gradient (m/m)

Spreadsheet

This spreadsheet uses the Manning formula to calculate the flow conditions in an open channel acting under gravity only. It includes the following functions;

Calculates the maximum flow of a liquid through an open channel under gravity
Users can specify a trapezoidal, triangular, parabolic or rectangular channel shape and dimensions of any size
User can alter all parameters including;
- Hydraulic Gradient
- Channel Roughness Coefficient
Output
- Gives maximum flow of channel in l/s and m³/s
- Flow of pipe running full is plotted on a chart alongside other hydraulic gradients allowing the designer to quickly see how the gradient affects the flow
- Gives average flow velocity of the water in m/s