## Equations

**Manning**: Manning's equation has been applied to open channel flow computations with success in a wide range of conditions. The coefficient n is intended to represent the effects of boundary roughness only. The exponents on other variables were verified with 160 sets of data from experimental and natural channels that were observed by Bazin, Kutter, and others. Mississippi River data observed by Humphreys and Abbot were not used. In practical applications the energy slope is most appropriate for this equation, but water surface slope can be used if the flow is uniform.

**Reference**:

Dooge, J.C.I., 1991, The Manning formula in context; in

__Channel Flow:Centennial of Manning's Formula__ (

*B.C. Yen, editor*), Water ResourcesPublications, Littleton, CO., p. 136-185.

Yen, B.C., 1991, Hydraulic resistance in open channels; in __Channel Flow:Centennial of Manning's Formula__ (*B.C. Yen, editor*), Water ResourcesPublications, Littleton, CO., p. 1-135.