Manning's "n", developed overbank

[Ted in NJ]

Does anyone have a good source for recommended n-values for developed overbanks? The tables in the reference manual cover pavements and vegetated surfaces, but has anyone developed similar tables for residential neighborhoods, urban areas, etc.?

Ted

[ntrommler]

good point

I only know the Mannings n online reference provided by the USGS which is included in the Hec-Ras help menu.

sorry

[ntrommler]

there is a

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

provided by the United States Geological Survey

pfd download: http://www.humboldt.edu/~geology/for...39_netvers.pdf

hope that helps, at least a little

[Chris Maeder]

I've assembled and collected 3 different documents on selecting Manning's n roughness coefficients, with color and black-white photographs, from various government resources. You can download them as PDF files from here:
http://www.bossintl.com/products/dow...iverCAD.html#9