Manning's roughness coefficients (n-values) have been computed from hydraulic and geometric data that were collected from selected streams in Illinois. In order to provide information for estimating n-values at other hydraulic and/or geometric conditions, the site- and event-specific data are organized into data pages using a format similar to the Barnes report (1967), which is known as the visual approach for estimating n-values. Stream reaches that are selected characterize those representing natural or man-made cross sections, natural or artificial surface roughness, and in rural or urban settings. Efforts are made to include a range of n-values computed from hydraulic data collected at different stages or discharges at a site. Attempts also are made to enhance the presentation of the topographic features of a study reach; and to describe the geometric and hydraulic factors pertaining to the computed n-values in the site descriptions.
The USGS Illinois Water Science Center (USGS – IWSC) and the Illinois Department of Natural Resources - Office of Water Resources (IDNR-OWR) conducted this study. Using links provided at the left-hand-side of the Web, readers can view or download these site data pages. Readers can also link to reports of similar studies conducted at other Water Science Centers of the U.S. Geological Survey (USGS) or other agencies, to compute n-values using various methods that can be found in literatures, and to search for sites that have the range of n-values specified by the readers. Other search or computational functions will be provided when feasible. To view the study report, use the links provided at the end of this page.
The Web page being continuously revised so it can provide information to users in the most clear and useful form. Please forward any comments to David T. Soong or Teresa M. Halfar (USGS), or Loren Wobig (IDNR-OWR).
USGS:
David T. Soong: dsoong@usgs.gov, phone: 217 344 0037 ext. 3055, fax: 217 344 0082
Teresa M. Halfar: thalfar@usgs.gov, phone: 217 344 0037 ext. 3036, fax: 217 344 0082
Megan A. Jupin: mjupin@usgs.gov, phone: 217 344 0037 ext. 3035, fax: 217 344 0082
IDNR - OWR
Loren A. Wobig: lwobig@dnrmail.state.il.us, phone: 217 782 9130, fax: 217 785 5014
This web page is still under construction. Many web functions will be developed in the future. Provisional data are for review/comment only. Your comments and suggestions are invaluable to us for serving the information/results better.
Disclaimer
USGS data on this page have not
received Director's approval and as such are provisional and subject to revision. The data are released
on the condition that neither the USGS nor the United States Government may be held liable for any damages
resulting from their use.
Data from other agencies are displayed for informational purposes only. The USGS is not involved with
the collection, checking, and analysis of other agency data. Questions and/or comments concerning other
agency data should be directed to the respective agency.
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://il.water.usgs.gov/proj/nvalues/index.shtml
Page Contact Information: David Soong
Page Last Modified: Tuesday, 12-Feb-2008 14:54:07 CST
