The Manning Equation for Open Channel Flow Calculations (English Edition)

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: i) flow rate and/or average velocity, ii) bottom slope of the channel, iii) cross-sectional area of flow, iv) wetted perimeter, v) and Manning roughness coefficient for the channel surface. The term "open channel flow" is used to refer to flow with a free liquid surface at atmospheric pressure, in which the driving force for flow is gravity. Pipe flow, on the other hand, is used to refer to fluid flow in a closed conduit uner pressure, in which the primary driving force for flow is typically pressure. Open channel flow occurs in natural channels, such as rivers and streams, and in manmade channels, such as those used for storm water, waste water and irrigation water flow. This book is about open channel flow, and in particular, about uniform open channel flow, in which the channel slope, water velocity, and water depth remain constant. There is emphasis on calculations with the Manning equation and the use of Excel spreadsheets for those calculations. There is also coverage of several different ways in which open channel flow is classified, including clarification of the difference between uniform and non-uniform open channel flow.