The Manning equation is a widely used empirical equation for uniform open channel flow of water. It provides a relationship among several open channel flow parameters of interest: flow rate or average velocity, bottom slope of the channel, cross-sectional area of flow, wetted perimeter, and Manning roughness coefficient for the channel. Open channel flow takes place in natural channels, such as rivers and streams, as well as in manmade channels.

Upon completion of this course, the learner will:

• Know the differences between laminar & turbulent, steady state & unsteady state, and uniform & non-uniform open channel flow.
• Be able to calculate the hydraulic radius for flow of a specified depth in an open channel with specified cross-sectional shape and size.
• Be able to calculate the Reynolds Number for a specified open channel flow and determine whether the flow will be laminar or turbulent flow.
• Be able to use tables such as the examples given in this course to determine a value for Manning roughness coefficient for flow in a manmade or natural open channel.
• Be able to use the Manning Equation to calculate volumetric flow rate, average velocity, Manning roughness coefficient, or bottom slope, if given adequate information about a reach of open channel flow.
• Be able to use the Manning Equation, with an iterative procedure, to calculate normal depth for specified volumetric flow rate, channel bottom slope, channel shape & size, and Manning roughness coefficient for a reach of open channel.
• Be able to make Manning Equation calculations in either U.S. units or S.I. units.
• Be able to calculate the Manning roughness coefficient for a natural channel based on descriptive information about the channel.
• Be able to carry out a variety of calculations for full or partially full flow under gravity in a circular pipe.