TxDOT Research Library - Publication Details

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Title:

Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Flood Plains

Authors:

by G. J. Arcement Jr. and V. R. Schneider

Published:

1984

[Washington, D.C.]

United States. Federal Highway Administration

Type:

Hard copy + Online document

1 volume (vi, 62 pages)

Online Access:

https://www.fhwa.dot.gov/bridge/wsp2339.pdf

Access Note:

10.6 MB

Summary

Although much research has been done on Manning's roughness coefficients for stream channels, very little has been done on the selection of roughness values for densely vegetated flood plains. A procedure for the determination of Manning's roughness coefficient (n) for channels and flood plains analyzes the different roughness factors that affect the roughness coefficients for channels and flood plains. By determining the value of each factor and combining those values, the n value can be determined. Another procedure deals with densely vegetated flood plains where the major roughness is caused by trees, vines, and brush. The n value for this type of flood plain can be determined by measuring the "vegetation density" of the flood plain. Photographs of flood plain segments where n values have been verified are presented as a comparison standard to aid in assigning n values to similar flood plains.

Publ. Place

[Washington, D.C.]

Contents

Introduction --
Approach --
Method for Assigning N Values for Channels --
Methods for Assigning n Values for Flood Plains --
Photographs of Flood Plains --
Procedures for Assigning n Values --
Summary --
Selected References

Notes

"April 1984"