Difference between revisions of "Manning's n"

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|Where the average depth of flow is at ≥ 2 times the height of the vegetation
 
|Where the average depth of flow is at ≥ 2 times the height of the vegetation
 
|Supple tree seedlings such as willow or cottonwood growing where the average depth of flow is at ≥ 3 times the height of the vegetation
 
|Supple tree seedlings such as willow or cottonwood growing where the average depth of flow is at ≥ 3 times the height of the vegetation
|!0.010 - 0.025  
+
|-
 +
!0.010 - 0.025  
 
|Where the average depth of flow is between 1 - 2 times the height of the vegetation
 
|Where the average depth of flow is between 1 - 2 times the height of the vegetation
 
|Moderately dense weeds, or tree seedlings growing where the average depth of flow is from 2 -3 times the height of the vegetation  
 
|Moderately dense weeds, or tree seedlings growing where the average depth of flow is from 2 -3 times the height of the vegetation  
 +
|-
 
!0.025 - 0.050
 
!0.025 - 0.050
 
|Where the average depth of flow is about equal to the height of the vegetation
 
|Where the average depth of flow is about equal to the height of the vegetation
 
|8- to 10-year-old willow or cottonwood trees inter-grown with some weeds and brush (none of the vegetation in foliage)
 
|8- to 10-year-old willow or cottonwood trees inter-grown with some weeds and brush (none of the vegetation in foliage)
 +
|-
 
!0.050 - 0.100
 
!0.050 - 0.100
 
|Where the average depth of flow is < 0.5 times height of the vegetation
 
|Where the average depth of flow is < 0.5 times height of the vegetation
 
|bushy willow trees about 1 year old inter-grown with weeds along side slopes (all vegetation in full foliage)
 
|bushy willow trees about 1 year old inter-grown with weeds along side slopes (all vegetation in full foliage)
 
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|}

Revision as of 17:48, 19 December 2017

Manning's 'n' of vegetated surfaces [1]
Value range Good condition turf grass Other
0.002 - 0.010 Where the average depth of flow is at ≥ 2 times the height of the vegetation Supple tree seedlings such as willow or cottonwood growing where the average depth of flow is at ≥ 3 times the height of the vegetation
0.010 - 0.025 Where the average depth of flow is between 1 - 2 times the height of the vegetation Moderately dense weeds, or tree seedlings growing where the average depth of flow is from 2 -3 times the height of the vegetation
0.025 - 0.050 Where the average depth of flow is about equal to the height of the vegetation 8- to 10-year-old willow or cottonwood trees inter-grown with some weeds and brush (none of the vegetation in foliage)
0.050 - 0.100 Where the average depth of flow is < 0.5 times height of the vegetation bushy willow trees about 1 year old inter-grown with weeds along side slopes (all vegetation in full foliage)
  1. Arcement, G.J., Schneider, R. Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Flood Plains U.S.G.S. WATER-SUPPLY PAPER 2339, 1989 http://eh.sdsu.edu/usgs_report_2339.pdf Accessed Dec 19 2017