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Data Series 668

In Cooperation with the Illinois Department of Natural Resources—Office of Water Resources

Manning's Roughness Coefficients for Illinois Streams

By David T. Soong, Crystal D. Prater, and Teresa M. Halfar, and Loren A. Wobig

Thumbnail of and link to report PDF (1.34 MB)Abstract

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

First posted April 27, 2012

For additional information contact:
Director, Illinois Water Science Center
U.S. Geological Survey
1201 W. University Avenue, Suite 100
Urbana, Illinois 61801

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

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


References Cited

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