Estimating Roughness Coefficients

:: Use of this Search Engine :: Computational Tools ::


:: Presentation and Comparison of Selected Streams :: Entering the range of n-values :: Addition of data to the database ::

This website essentially has two functions: (1) it allows the user to compare data from a searchable database, and (2) it allows the user to interactively enter variables into a variety of hydraulic equations that solve for the unknown variable in the equation.

Presentation and Comparison of Selected Streams:

The database can be accessed via the web pages in several different ways. The user can query the database by entering a range of n-values, or by selecting specific site characteristics. The results of the query can then be presented and compared to a stream for which the user is attempting to determine the roughness coefficient.

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Entering a range of n-values:

The user can specify a range of n-values of interest. A list of the available data matching the range, or in the case that no available data are available in the specified range, the data closest to the entered range, will be listed in order of the best match.

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Addition of data to the database:

This website will be maintained by the USGS, Illinois District. A download button is also available on the website for users who wish to burn their own CD-ROM for use in the field. The user can download updated versions as they deem necessary. If you or your organization have additional data which could be added to the data base, or if errors are found in the data, please contact David Soong, Crystal Prater, or Teresa Halfar at the USGS.

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:: Calculations using hydraulic and/or geometric data ::

These web pages also have an interactive utility that allows the user to enter variables into a variety of hydraulic equations. Most of these equations were developed for specific stream characteristics, so a more in-depth knowledge of the references that each of the equations comes from could be helpful to the user.

Calculations using hydraulic and/or geometric data:

For any of the variety of equations listed, the user can enter known hydraulic and geometric data in the appropriate fields and click the "Calculate" button to determine the unknown value. Then, if the user wishes to compare the calculated value to sites with the same or similar values, they can click on the "Similar n-values" button. This action will automatically insert the calculated n-value into both the maximum and minimum fields for the range of n. Clicking on the "Next" button will take the user to the database.

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Page Contact Information: David Soong
Page Last Modified: December 19, 2012