Description

Computations involving flow in open channels commonly require an evaluation of the roughness characteristics of the channel. The Manning equation has been used extensively as an indirect method for computing discharge or depths of flow in natural channels. The U.S. Geological Survey engages in a continuing effort to improve the understanding of flow resistance, usually in terms of Manning's roughness coefficient, n, in channels in the United States. Procedures for computing values of Manning's roughness coefficient from known discharge, water-surface profiles, and channel cross-sectional properties are presented and have been programmed for automatic computation. General theory, procedures for onsite investigations and surveys, a description of the use of the computer program, an example problem, and additional channel-roughness- verification research needs are provided (Jarrett and Petsch, 1985).

URL

https://water.usgs.gov/cgi-bin/man_wrdapp?ncalc

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Last modified: July 13, 2020, 3:19 p.m.