Manning Open Channel Design Spreadsheet

Manning Open Channel Design Spreadsheet

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

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)



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;
  • 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

Download Free Trial Version

To try out a fully functional free trail version of this software, please Click Here or enter your email address below to sign up to our newsletter.

    Get the full license version now for only £10.

    All purchases are covered by our full money back guarantee.

    License Type