Data Series 668
Manning’s roughness coefficients for 43 natural and constructed streams in Illinois are reported and displayed on a U.S. Geological Survey Web site. At a majority of the sites, discharge and stage were measured, and corresponding Manning’s coefficients—the n-values—were determined at more than one river discharge. The n-values discussed in this report are computed from data representing the stream reach studied and, therefore, are reachwise values. Presentation of the resulting n-values takes a visual-comparison approach similar to the previously published Barnes report (1967), in which photographs of channel conditions, description of the site, and the resulting n-values are organized for each site. The Web site where the data can be accessed and are displayed is at URL http://il.water.usgs.gov/proj/nvalues/.
First posted April 27, 2012
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Soong, David T., Prater, Crystal D., Halfar, Teresa M., and Wobig, Loren A., 2012, Manning’s roughness coefficient for Illinois streams: U.S. Geological Survey Data Series 668, 14 p.
Field Data Collection
Presentation of n-values on the Web Site
Summary and Conclusion