The following is one of over 75 programs & documentation included with Hydro-CD by Dodson

Manning "n" Values (description & expamples)

1. Hands-On HEC-2 by Dodson (1998) - Chapter 2. Stream Hydraulics (2-5 to 2-8)

2. Roughness Characteristics of Natural Channels, by HARRY H. Barnes,JR., Geological Survey Water-Supply Paper 1849, U.S.G.S., Washington, 1967.

The Manning "n" value is an experimentally derived constant which represents the effect of channel roughness in the Manning equation. Considerable care must be given to the selection of an appropriate "n' value for a given channel due to its significant effect on the results of the Manning equation. Tables 2.1 through 2.5 provide a listing of "n" values for various channel conditions. Color photographs of natural channels exhibiting various values of n may be seen in [BARNES, 1967]. These photographs were made after a large flow and the n-values calculated based on the large flow.


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